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How to cite this thesis
Surname, Initial(s). (2012) Title of the thesis or dissertation. PhD. (Chemistry)/ M.Sc. (Physics)/ M.A. (Philosophy)/M.Com. (Finance) etc. [Unpublished]: University of Johannesburg. Retrieved from: https://ujdigispace.uj.ac.za (Accessed: Date).
Gf-t it-
LIFE CYCLE MANAGEMENT FOR POWER
TRANSFORMERS USED INTHE ESKOM DISTRIBUTION
NETWORK-CASE STUDY.
By
SARAH REFILWE MPHO CHILWANE
920202933
A DISSERTATION SUBMITTED IN PARTIAL
FULFILMENT OF THE REQUIREMENTS FOR THE
DEGREE
MAGISTER INGENERIAE
IN
ENGINEERING MANAGEMENT
IN THE
FACULTY OF ENGINEERING
AT THE
UNIVERSITY OF JOHANNESBURG
February 2011
SUPERVISOR: PROF.JHC PRETORIUS
CO SUPERVISOR: DR OJ KRUGER
Page i
ABSTRACT
Title:
Author:
Supervisor:
Co-Supervisor:
Degree:
Keywords:
Life cycle management for power transformers used in the
Eskom Distributionnetwork - casestudy.
Sarah Refilwe Mpho Chilwane
Prof. JHC Pretorius
Dr. DJ Kruger
Master in Engineering Management
life cycle, asset, risk, transformer, reliability, condition
monitoring.
Electricity is a crucial key component in every day life influencing the economy,
safety; health, productivity and comfort just to name a few. The benefits and
importance of electricity can be easily taken for granted by the consumer.
Towards the end of 2007, South Africa suffered numerous power outages and that
lead to the implementation of load shedding byEskom, the electricity utility in South
Africa, in order to manage the shortage ofelectricity [1].
Electricity utilities constantly make decisions that affect the cost, reliability and
quality of their services. Therefore engineering designs and maintenance strategies
should be updated frequently. The benefits ofthese updates to the system would have
a significant performance improvement inregards to reliability and the quality of the
electricity. The outline of asset management is therefore to focus on the business
assets so thatthe organisation could serve the customers effectively.
As a result, the focus for the research is to develop a life cycle management plan for
one of the main assets utilised in the distribution networknamely power transformers.
The researchwould include a study of power transformers and customs that could be
used to improve the reliability, logistics, safety and the capital investments of the
network.
Page ii
Power transformers are static equipment, and failure rate is very low compared to
other assets found in substations. As a result of their sizes, transformers requires
more time and special arrangements should a failure occur. A risk and condition
analysis was conducted on transformers and the results and conclusions were
discussed.
Page iii
ACKNOWLEDGEMENT
There are many people who have supported and encouraged me during this project
investigation. This meant a lot to me and I am very grateful. I would like to take this
opportunity to acknowledge the following peoples for their various contributions to this
thesis.
First I would like to thank my study leaderProf. Jan-Harm C Pretorius and my mentor
James Motladile for their patience and the time spent in assisting me with this project.
My parents have supported me from pre-school till today andhave inspired me in my
studies; I thank you very much for everything. To my sisters Paballo and Pontsho,
thank you for your support, and the cups of coffee you havemade mewhilst I was busy
with the document and the dance lesson when I was taking a break.
I would like to give a special thanks to my friends.
Finally, I am grateful to my husband Mzwandile Buthelezi, who in many ways has
contributed to myproject, discussing research with me, and taking care of me when the
project demanded all my time.
Pageiv
DECLARATION
It SARAH CHILWANE hereby declare that all work presented within this report is
solely my work and that any research as well as information obtained from outside
sources have been referenced to the best ofmy abilities.
Sarah Chilwane
October 2010
Page v
TABLE OFCONTENTS
ABSTRACT 11
ACKNOWLEDGEMENT IV
DECLARATION V
NOMENCLATURE X
CHAPTER 1- RESEARCH BACKGROUND AND PROPOSAL•• 1
1.1 PROJECT BACKGROUND 1
1.2 AIM 1
1.3 OBJECTIVES 2
1.4 RESEARCH METHODOLOGy 2
1.5 OVERVIEW OF DISSERTATION 2
1.6 CONCLUSION 3
CHAPTER 2-INTRODUCTION 4
2.1 INTRODUCTION 4
2.2 DIVISIONS INTHE UTILITY 4
2.3 LIFE CYCLE MANAGEMENT PLAN 10
2.4 ASSETS MANAGEMENT 12
2.5 LITERATURE SURVEy 13
2.6 SCOPE OF WORK 15
2.7 CONCLUSION 15
CHAPTER 3- CONCEPTUAL PHASE 163.1 INTRODUCTION..................... 16
3.2 DISTRIBUTION ENGINEERING 16
3.3 THE ELECTRICITY UTILITY'S APPROACH ON LIFE CYCLE
MANAGEMENT 23
3.4 LIFECYCLE MANAGEMENT PLAN (LeMP) STANDARDS 25
3.5 THE ASSET MANAGEMENTSYSTEM 27
3.6 ASSET MANAGEMENT PROGRAMME 28
Page vi
3.7 CONCLUSION 30
CHAPTER4- CASE STUDY - POWER TRANSFORMERS 31
4.1 INTRODUCTION 31
4.2 THE RECOMMENDED LIFE CYCLE MANAGEMENT OF POWER
TRANSFORMERS 31
4.3 ASSET RISK METHODOLOGy 39
4.4 CONCLUSION 43
CHAPTER5- CONCLUSION 44
5.1 INTRODUCTION 44
5.2 GENERAL CONCLUSION 44
5.3 PROPOSED FURTHER WORK 45
APPENDIX A: CENTRAL REGION MAP 47
APPENDIX B: POWER TRANSFORMER FMEA 48
REFERENCES 68
Page vii
TABLE OF FIGURES
Figure 1:Thedistribution process of electricity [6] 5
Figure 2: Evolution ofSouth Africa's energy supply from 1971 to 2007 [9] 6
Figure 3: Eskom Transmission station 7
Figure 4: Servitude required for transmission lines [11 ] 8
Figure 5: Pole mounted distribution transformer 9
Figure 6: Lifecycle phases of process asset system [16] 10
Figure 7: Loop diagram showing the relationship between elements of a
system [17] 11
Figure 8: Ideal power quality at 1.0 p.u and 50 Hz sinusoidal voltage [33] 17
Figure 9: Real power quality, the distorted voltage waveform [33] 17
Figure 10: Value chains utilised in Eskom Distribution [5] 19
Figure 11: Current distribution initiatives that relate to asset management [4].
.......................................................................................................................22
Figure 12: Integration of project, asset and product life cycles [43] 23
Figure 13: Life cycle management of electricity in Eskom [44] 24
Figure 14: Contribution of functions in an organisation [29] 25
Figure 15: Levels of assetsand theirmanagement [32] 27
Figure 16: Asset lifecycle framework [47] 28
Figure 17: The decision support mechanism of life cycle engineering [51] 32
Figure 18: Active part of a transformer 33
Figure 19: The Bathtub Curve [56] 36
Figure 20: Asset risk management model [4] [57] 39
Figure 21: Model used to calculate asset risk [4] .40
Page viii
LIST OF TABLES
Table 1: Eskom Distribution asset management programme [2] [49] 30
Table 2: Transformer risk analysis 34
Table 3: Failure Mode effect and analysis for powertransformers 35
Table 4: Preventive maintenance plan for transformers 37
Table 5: Assessing the risks associated with operation and maintenance of an
asset [4) [59) 41
Table 6: Operational and Maintenance Risk Contribution [4] [55] 42
Table 7: Environmental factors included in the Risk Model [4) [55] [59] 42
Page ix
NOMENCLATURE
AC
BSI
CAPEX
FMEA
HV
Hz
IBR
IEEE
ISO
IP
IT
Ian
KPI
LCA
LCI
LCIA
LCMP
LCM
LPU
LV
MN
MADS
MRC
MV
MW
NAC
NERSA
NDP
OPEX
PAS
alternating current
British Standards Institution
capital expenditure
failure mode effect andanalysis
high voltage
hertz
incentive-based regulation
Institute of Electrical and Electronics Engineers
International Organisation for Standardisation
intellectual property
information technology
kilometre
Key Performance Index
life cycle assessment
life cycle inventory
lifecycle impact analysis
life cycle management plan
life cycle management
large power users
low voltage
maintain network
manage availability of supply
manage revenue cycle
medium voltage
megawatt
network asset creation
National Energy Regulator of South Africa.
network development plan
operational expenditure
Publicly Available Specification
Page x
PHI
pu
SPU
SAlOl
SAIFI
SMS
USPTO
WIPO
ZAR
Ac
ARV
AR
P
Afr
OMfr
Enfr
plant health index
perunit
small power users
system average interruption duration index
system average interruption frequency index
short message sending
United States Patent and Trademark Office
World Intellectual Property Organisation
South African Rand
Asset criticality
Asset replacement value
Asset risk
Probability of asset failure
Asset failure rate
Operation and maintenance failure rate
Environmental factors failure rate
Page xi
Chapter J: Research background and proposal
CHAPTER 1- RESEARCH BACKGROUND AND PROPOSAL
1.1 PROJECT BACKGROUND
Eskom is oneofthe ten largest electricity providers in the world [I]. The major objectives of
the utility are to generate, transmit and distribute electricityto consumers in South Africa and
certain neighbouring countries [2].
The utility has three major divisions namely Generation, Transmission and Distribution.
These divisions consist of entities such as power generating substations, power lines,
substations, mini-substations and other equipments used during the generation of power [3].
The equipment and the different divisions involved at the electricity utility makes it an asset
centric organisation. If a transformer or any other equipment in the electricity delivery
network fails then the customers supplied from that equipment will be affected by that
failure. As a result, assets used in the business ofelectricitysupply, should be maintained and
monitored consistently.
Electricity distribution networks have primary and secondary substations. Primary
substations deliver energy to secondary substation and the secondary substations have the
responsibility of delivering that energy in a safe, measurable and sustainable manner.
Through thisprocess the end-userwill receive operable energy.
1.2 AIM
This dissertation aims toconduct research on power transformers within Eskom Distribution
inthe central region (see Appendix A for region map). The desired outcomes are to develop
a structured plan for the region and introduce a life cycle management plan for power
transformers. As well as to develop a procedure that could improve the reliability,
performance andmaintenance of power transformers used in Eskom's distribution networks.
Page I
Chapter 1: Research background and proposal
1.3 OBJECTIVES
• To provide a process by which the applicable transformer's life cycle plans wouldbe
compiled, reviewed and managed.
• To determine a detailed and measurable level of performance or condition required of
the transformers.
• To analyse risk methodologies that can be applied to transformers in the process of
developing their asset management plans.
1.4 RESEARCH METHODOLOGY
In this section a list of procedures used in the research are presented. These procedures are
important in determining thesuccess of thestudy:
a) A generalised study was developed to highlight the value chains used in the
organisation.
b) A detailed risk assessment for power transformers was developed. The results
thereof give a guideline of the management for power transformers [4].
c) The information acquired from the value chains provide an understanding on
how the different departments relate to each other. It also highlights how the
organisation incorporates life cycle management [5].
d) A case study on one of the power transformers used In the utility was
performed. This case study illustrates the practical application of the risk
assessment methodology.
1.5 OVERVIEW OF DISSERTAnON
Chapter 1 is an introduction to the information contained in this document and an overview
on the importance of life cycle management and asset management. It contains a brief
description of the departments found in theelectricity utility. The objective and goals of the
dissertation are also discussed.
Page 2
Chapter J: Research background and proposal
Chapter 2 forms the conceptual phase of this dissertation. It provides a description of
Eskom's distribution departments and the value chains involved in the management of the
network. It provides an overview of the importance of life cycle management and asset
management in Eskom Distribution.
Chapter 3 is the implementation phase if the research. It provides a thorough investigation
and plan for asset management of power transformers used in Eskom Distribution. It outlines
the different stages involved in asset management and the asset management strategies
namely maintenance, refurbishment and network strengthening.
Chapter 4 provides a discussion and final conclusion to this dissertation. Within this chapter
the objectives of this dissertation as well as the shortcomings will be discussed. Before final
conclusion recommendations for further work required willbe discussed.
1.6 CONCLUSION
This chapter forms part of the research proposal for this study. A work plan on how the
research will be conducted is developed and tabulated. Chapter I provides the project
background and research objectives of thisstudy. During the execution of the work plan the
research methodology will be implemented.
As part of the research proposal, the issues tobe addressed arealso listed. Chapter I provides
information thatjustifies the requirement toconduct this study. Assumptions have to be made
and contingency have to be in place in the event that the research does not follow what is
specified in thework plan. The following chapter is the introduction ofthis dissertation.
Page3
Chapter2: Introduction
CHAPTER 2 - INTRODUCTION
2.1 INTRODUCTION
Eskom was established on 151 of March 1923. The South African public and industry
consumes 95% of the electricity that is generated by Eskom. Theutility is the largest
producer of electricity in Africa and is the eleventh largest in the world in terms of
generation capacity [3].
The client in this case is Eskom Distribution, which has a distribution network of
320,035 kilometres of line and 3.6 million customers, including major wholesale
customers in municipalities, aluminium smelters and railways.
The three main divisions in utility (Generation, Transmission and Distribution) are
responsible for electricity delivery to the end user would be discussed briefly in the
following section.
2.2 DIVISIONS IN THE UTILITY
There are many different ways to generate electricity using natural resources such as
coal, oil, gas, hydroelectric, nuclear, geothermal, solar, andwind. The delivery of this
electricity to the consumer is one of the key components in the business that is
complicated and sensitive.
Page 4
generated at it is
relevant customers,
p!pf'tl"1i{'ih, is supelted to consumer 1S illustrated
RIltICUIlitlon LVLk1IlII(3l1tl~2211V)
L
DISTRIBUTION(132-33 kV)
lklr-.Comwlltion
1:The distribution process [6],
A brief explanation of key
in I will beexplained
2.2.1. GENERATIONSrsTEM
in the electricitydelivery system that
the following sections.
electrical generation £1""811011 is one of
In total
"""rtf"::""t""", to
stations throughout the {'""nt'Mt' are
an
installed C~lpaCJlty that exceeds Electricity is generated
use nt' ...."l",,,, .. technolcgv
s
illustrates South can see a Ilfowirlll
I I till
South Africa's historical energy supply
400
200
200
1973 1975 1977 1979 1981 1983 1985 1987 1989 1991 1993 1995 1997 1999 2001 2003 2005 2007
Veal1l• Cl>lll • Oil IIIGl!ll\l l:l ttu:hIat I tl{dro III CorriH_ &w IlIlte • Geoll1!!rmllllllotllrlwlnd
Figure 2: Evolution of South Africa's energysupplyfrom 1971 to2007 [9].
In South the utility produces over 000 MW of electricity to meet the
current demand andthis growing annually [7]. Therefore, for that reason, the
utility uses over 1000 tonnes of low quality coal in the production some of the
lowest-costindustrial in theworld [2].
generated electricity will transported for long distances
from the generation substation. The complex transmission system
IS explained inthe fi)ll.nwinc7 section.
at stations to
voltaze reduced to at 11 means
6
400
[10]
are
is
at
over a
3 illustrates a transrnission stations. A transmtssion
andmaintenance.
covers
Figure 3: Eskom Transmission station,
<:lpl"lIitncip<:l rlPlruu'fm,pnf within are responsible
coverage areasome
next. 2
to
up toa maximum
one station to
7
Chapter 2: Introduction
The transmission lines in the ce ntral region transport approximately 22 percent of the
total electricity supply in outh Africa (7]. Figure 4 illustrate servitude needed for
transmission lines.
Figure 4 : Servitude required for tran smi ssion lines [ I I].
Servitude is a registered right that a person has over the immovable property of
another [12]. This means that Eskom has the right to install structures or equ ipment
within its registered servitude.
2.2.3. D ISTRlIW TlON SYSTEM
Eskorn Distribution division w ithin Eskorn 's business has the re ponsibilit y to deliver
electricity erv ices, maintaini ng the distribution network and ensuring e ll toni er
satisfaction. Thc distribution sys tem cons ists of a distribution substation, distribution
lines. reticulation lines and crv icc connection as illustrated in Figure I
Page 8
on to an overhead
5: Pole mounted distribution transformer.
are different
distribution svsrern is
It incorporates equipment to nrevent or to
9
Aceordinz to
IS "mltel111ed to nr(\111111f' an ettective tons-term
to
an
are a
conception to retirement or disposat [14]. Itaddresses
maintenance (nreventative or corrective) replacement, or redesign a
nrovtdes an orgamsanon a concept
or irnnroved sustainability adopting this concept an organisation can improve on
,"","nt'p< OI [13] [15],
asset [16], It an assets
to retirement or
AC1QUlisition phase Uliliisalion phase
Chapter 2: Introduction
2.3.1. LIFE CYCLE COST
A part of life cycle management is based on the cost associated with asset life cycle.
G.1. Thuesen, W.J. Fabrycky, defines life cycle cost as "all costs, both nonrecurring
and recurring, that occur over the life cycle" [16].
Life cycle cost should be analysed early in the planning, design and development of
an assets. This will ensure that the lifecycle cost in the operational phase is low. The
network condition will degrade over time; this will affect the network performance
which leads to the investments of the organisations. These investments can either be
capital expenditure (CAPEX) or operational expenditure(OPEX). Figure 7 illustrates
the relationship between elements of a network system [17].
(P.~~~Network
/': Condition"'" Internal( , Performance
Ageing CAPEX ~Target
Factoll 1Time
Investment
Re~.ources~) ~R1 Revenue ............. /'I ~ / v > customers
OPEX~ Demand
Customers
Distribution network operatorNotationB=Balancing FeedbackR=Reinforcing Feedback
Figure 7: Loop diagramshowing the relationship between elements ofasystem [17].
The contributing factors that determine the condition of a network are CAPEX for
acquiring power transformers, resources required for maintenance and in-service
operation of transformers. OPEX is used for reinforcing the network and to maintain
the condition ofpower transformers,
Page 11
Chapter2: Introduction
2.3.2. IMPORTANCE OF A LIFE CYCLE MANAGEMENT PLAN
Electricity utilities, like Eskom, utilise lifecycle management to integrate operations,
maintenance, engineering, regulatory, environmental and economic planning
activities. This is done in a manner that manages aging, obsolescence and
preventative maintenance of the system.
Life cycle management planning provides an effective long-term planning tool. This
can be used to minimise unplanned capability loss, optimises operating life, and
maximises the returnof investment while maintaining network safety[18].
2.4 ASSETS MANAGEMENT
The formal definition of asset management from Publicity Available Specification
(PAS) 55 is: "Systematic and coordinated activities and practices through which an
organisation optimally manages its assets, and their associated performance, risk and
expenditures over their lifecycle for the purpose of achieving its organisational
strategic plan" [19] [32]. PAS 55 will be explained in detail in the following chapter.
An asset management plan (AMP) is a tactical plan that is used in an organisation to
manage its infrastructure and assets. AMP is put in place to ensure that services
rendered are at an acceptable quality and regulating standards. This plan is most
effective where a number of assets are co-dependant and must work together to
deliver a service[15].
Page 12
Chapter 2: Introduction
2.4.1 IMPORTANCE OFAN ASSETMANAGEMENT PLAN
It is important to note that an asset centric organisation should understand and
implement the asset management principles. By implementing these principles the
organisation will receive long term benefits. In Eskom Distribution an asset
management plan will provide measures to sustain the supply of electricity. To
further understand the topic of asset management, the following definitions will be
stated:
Asset: Physical, immovable substation equipment or infrastructure that forms part of
an electricity utility. Allocation of high voltage (HV), medium voltage (MV) and low
voltage (LV) networks, and that has a direct impact on the life cycle of the power
network [20].
An asset management plan is a tool that will provide the utility with information
regarding stock that they posses [21]. In the event of long-lead material failure, the
utility will have information about the time schedule and the location of replacement
equipment. With an asset management plan in place, the duration of outages will be
minimised.
2.5 LITERATURE SURVEY
World wide there have been efforts made by utilities to manage assets that are an
important component in the electricity delivery system [22]. In this section of this
dissertation aninvestigation is conducted to determine existing lifecycle management
of power transformers.
In utilities the reliability and functionality of power transformers under load has great
importance, therefore the asset management of power transformers is crucial [22]
[23]. The life cyclemanagement of utilitytransformer asset is nota new concept and
has been previously done by other utilitiessuch as in the United States.
Page 13
Chapter 2: Introduction
An intellectual property (IP) search for power transformer management was
conducted using the United States Patent and Trademark Office (www.USPTo.gov)
World Intellectual Property Organisation (www. W/po.int) and free patents online
(wwH'.{i-eepofen,wn!il/e.('om), Prior art was found relating to power transformers,
design specifications, transformer ratings and power transformer management. With
regards to life cycle management of a utility's power transformers, no art was found.
A search was conducted on the following peer reviewed electronic-resources for "life
cycle management of power transformers" for any publications, journals, magazines
and standards:
• IEEE (Institute of Electrical and Electronics Engineers) Xplore Digital
Library[22] [24] [25] [26],
• ScienceDirect search engine [27],
• Googlescholar [19] [28].
"Power transformer critical diagnostics for reliability and life extension" was one
result that was found from the search conducted. The other result found from the
search was "Power transformer condition monitoring and life-cycle management"
which provides earlydetection measures to manage the risk of developing failure for
power transformers.
The same search was conducted on Eskom's intranet database for "life cycle
management of power transformers" within Eskom Holdings Ltd Pty. It was found
that there was previously an intension to research into the implementation of an asset
management plan for transformers but this did not materialise. The performance and
reliability of power transformers can be increased by establishing management
strategies [23].
The introduction of a life cycle management plan in Eskom for power transformers
will reduce unplanned outages as well as catastrophic transformer failures. This asset
management plan will be uniquely for the South Africa market due to electricity
supply shortages andthe high amount of illegal connections [29].
Page 14
Chapter2: Introduction
2.6 SCOPE OFWORK
This dissertation will only focus on the management of power transformers used in
distribution substations for central region. It will analyse the value chains used in the
engineering section of the utility and study the life cycle management approach that
electricity utilitiesmayfollow.
The asset management plan for power transformers will include a riskassessment and
a failure mode analysis of the transformers. Once the reliability studies are
conducted, a transformer maintenance planwill be developed.
2.7 CONCLUSION
In this chapter an overview of Eskom Holdings Ltd. was provided. The background
into the different departments found in Eskom Holding and their functions were
discussed. The importance of life cycle management plan and the definition of asset
management werediscussed briefly.
In the following chapter the conceptual phase of this study will be conducted.
Chapter 2 will investigate how the value chains in the electricity utility relate and
illustrate how life cycle management plan increases the reliability, availability,
quality, and safety the network.
Page 15
Chapter3: Conceptual Phase
CHAPTER 3- CONCEPTUAL PHASE
3.1 INTRODUCTION
In the previous chapter, explanations of thedepartments found in the electricity utility
as well as their impacts on the organisation were explained. The importance of life
cycle management for power transformers and the value chains used in the
organisation will be discussed in this chapter.
3.2 DISTRIBUTION ENGINEERING
The final step of the electricity utility is the distribution of electricity to the end-user.
This part of the network consists of power lines, substations,
mini-substations, andtransformers, Equipment failure withinthe distribution network
will result in poweroutages thereby negatively impacting the customers and affecting
the quality of supply.
The capability of a network to deliver the prescribed quality of uninterrupted power to
its customers is known as power system reliability. The standardelectricity reliability
indices that are used in a distribution network for maintenance and reliability of
equipments are [30] [31] [32]:
a) SAIDI (system average interruption duration index) whichis used to indicate
the duration over which the incidents or fault lasted in a particular feeder.
b) SAIFI (system average intenuption frequency index)which is used to indicate
how many time the system experienced faults.
These indices can have a negative impact in the management of the organisation's
asset if it is not regularly monitored. The frequency of asset failure implies that assets
are not maintained as required.
Page 16
Chapter3: Conceptual Phase
Quality of supply is the level to which electrical supply to a customer's facility
conforms to the requirements of the service [33]. Poor quality includes factors such
as voltage drops, power surges and deviations from ideal sinusoidal waveform.
Figure 8 illustrates the ideal power quality that an electricity utility aims to achieve.
Figure 8: Ideal power quality at 1.0 p.u and 50 Hz sinusoidal voltage [33].
Figure 9 represents the real power quality waveform; real power quality waveform
represents the actual reading on the power instrument. It includes distortion, noise
which is due to the influences that are experienced.
Figure 9: Real power quality, the distortedvoltage waveform [33].
The frequency is another factor that is affecting the quality of supply. The frequency
of Eskom's generators are synchronised to the national grid at a frequency of 50Hz.
Since electricity is generated and transmitted as AC (alternating current), monitoring
of the frequency provides information with regards the electricity demand from the
network. If the electricity demand decreases the frequency will increase and when the
demand increases the frequency will decrease.
Page 17
Chapted: Conceptua IPhase
Technical parameters of power quality are as follows:
a) Voltage regulation,
b) Voltage unbalance,
c) Voltage dips,
d) Voltage harmonics,
e) Voltage flicker,
f) System disturbances.
In a deregulated environment, electrical utilities are underconstant pressure to reduce
operating costs, improve on equipment availability, improve on electricity quality
received by customers and reduce carbon dioxide emissions [34]. The following is a
discussion on specific standards that regulate utilities on the quality of its supply.
Minimum standards
Certain aspects of power quality, such as voltage waveform quality, are managed
from a regulatory point of view by minimum standards, for example, low voltage
magnitude must bebetween90% and 110% of nominal voltage [35].
Minimum standards are appropriate in regulating these aspects as customerappliances
are designed to work within these limits, and there is little or no benefit in meeting
stricter standards. Yet minimum standards are not appropriate in regulating continuity
of supply performance as there is no incentive for a utility to improve performance in
networks where minimum standards arealready being met[35].
Incentive-Based Regulation (IBR)
Under IBR (incentive-based regulation) schemes utilities are financially rewarded or
penalised based on a change in performance level [35]. Improved performance
(typically based on the average total outage time experienced by customers) can, for
example, be rewarded by an allowed increase in tariff [36]. Reduced performance
would result in anassociated reduction in tariff, in otherwords, less revenue [35].
Page 18
Chapter3: Conceptual Phase
The first IBR scheme in South Africa was initiated by the National Energy Regulator
of South Africa (NERSA) for a 3 year(2006 -2009) multi year price determination for
Eskom Distribution [35]. This incentive scheme is focused on short term
improvements in reliability via OPEX (operational expenditure) activities such as live
line, maintenance and vegetation management [35] [37].
The performance of a network is mainly determined via the design characteristics of
the network like lengths of feeders, number of customers supplied per feeder, inter
connectivity between feeders and redundancy of equipment. These structural issues
are influenced by CAPEX (capital expenditure) investment decisions. A well
maintained and operated network canonly perform as well as is dictated by its design
characteristics [35].
Currently
3.2.1. VALUE CHAINS IN A DISTRIBUTION NETWORK
Eskom Distribution has strategies in place to achieve its primary objectives. These
strategies include organisational structures of the business. These structures are in the
form of value chains [38]. Figure 10 illustrates the value chains that apply in the life
cycle of the distribution network and its assets that are presently implemented in
Eskom Distribution.
!,IAN)
Optimiseh
custrmer }- Manage hInteranm Revenue }I Cycle
(OCI)
I I (MIlC)
I IJ II Manage Direct opnmree h
f1'l ) ____ -.J ustomer prqjeet Customer }:.......... -( leetrlncatlon Inn Interaction
(OCI)
~~C) (IUOS)
Figure 10: Value chainsutilised in Eskom Distribution (5).
Page 19
Chapter3: Conceptual Phase
3.2.1.1. Developand marketproductservices
Understanding the South African market is the initial partof this value chain. This
market involves internal, external, stakeholders, customers and the macro
environment. Once the investigation and forecasting into the market has been
completed; a marketing strategy can be developed to achieve ongoing business
sustainability, growth and profitability.
3.2.1.2. Manage availability ofsupply
This value chain focuses on the network management; it ensures the real time
management and control of the supply and demand for electricity is performed. The
processes involved innetwork management include [39]:
a) Managing network performance,
b) Managing planned and unplanned work,
c) Escalation ofabnormal situations
3.2.1.3. Manage revenue cycle
The management of revenue cycle covers the life cycle ofconvectional and prepaid
meters, from the time the meter is received from the supplier to the time it is
discarded. This includes quantifying the electricity usage and identifying customers
which are large power users (LPU) or small power users (SPU) then the billing
process can be conducted [40].
3.2.1.4. Network asset creation
The network asset creating is the planning process withinthe network distribution. A
network development plan (NDP) is generated by the network planning department.
It provides a guideline for defining the study area and theobjectives of the planning
study. The following take place in theengineering domain oftheutility [41]:
a) Network asset creation
b) Maintain network
c) Manage availability of supply
Page 20
Chapters: Conceptual Phase
The other departments that also participate in this process by providing valuable
inputs relating to their scope of work are as follows [41]:
a) Substation department focusing onthe primarysubstation refurbishment and
performance of the network.
b) Land and development department deals with all the environmental and
servitude acquisitions.
c) Electricity delivery departmentfocuses on the operational issues and control
substation refurbishment.
d) Finance department provides an understanding of the various economic
structures, financial data andindicators.
e) Project engineering department designs the proposed plans issued by the
planning department.
"Asset risk management should be incorporated and integrated into the value chains
and business processes so that it can inform asset replacement, refurbishment and
maintenance decision making" [4]. Figure lIon the following page, shows a high
level summary of Eskom Distribution current initiatives related to Asset
Management [4].
Page 21
THE
opPclrtunJlty to lderatlty
to
it requires product understlmdmg,
It
management is quahtative,
is
operational processes are consistent
resources, information
a
12: Illlegrallioll ofrsroiect.
replacernent or recessgn
13 represents
Figure 13: Life management ofelectricity inEskom
natural raw
as
are burnt raw materials
raw m:lt~riz:ll"
is tollow'ed
to a;erlera:te, transmu
or recoverv
in
become a
all QI\IISIOlllS in an organtaation is
different departments contribute to
.'fgure 14: Contributionoffunetions in an orgimis811ion
3.4 LIFECYCLE M)~NALGEME1ST PLAN (LCMP) STANDARDS
silIndartis set
ensures
standards accustom to,
are
Chapters: ConceptuaIPhase
a) ISO 14040 - Life cycle assessment; Principles and framework (2006),
ISO 14040:2006 describes the principles and framework for life cycle
assessment (LCA) including: definition of the goal and scope of the LCA,
the life cycle inventory analysis (LCI) phase, the life cycle impact
assessment (LCIA) phase, the life cycle interpretation phase, reporting and
critical review of the LCA, limitations of the LCA, the relationship between
the LCA phases, and conditions for use of value choices and optional
elements.
ISO 14040:2006 covers life cycle assessment (LCA) studies and life cycle
inventory (LCI) studies. It doesnot describe the LCA technique in detail, nor
does it specify methodologies for the individual phases of the LCA.
The intended application of LCA or LCI results is considered during
definition of the goal and scope, but the application itself is outside the scope
ofthis International Standard.
b) ISO 14044 - Life cycle assessment; Requirements and guidelines (2006),
ISO 14044:2006 specifies requirements and provides guidelines for life
cycle assessment (LeA) including: definition of the goal and scope of the
LCA, the life cycle inventory analysis (LCI) phase, the life cycle impact
assessment (LCIA) phase, the life cycle interpretation phase, reporting and
critical review of the LCA, limitations of the LCA, relationship between the
LeA phases, and conditions foruse of value choices and optional elements.
ISO 14044:2006 covers life cycle assessment (LCA) studies and life cycle
inventory (LCI) studies.
Page26
THE
integrated asset management is imnortant
are different
asset
in
orgamsanons in
assets can
15 can
from or strategic, nhvsieal
asset managementassets.
an organisational strategic
is designed to support
and in tum aiming to meet a
in
is prmnanly assessled is
3.6 MA,NAGEME:NT PROGRAMME
managemen; is an nnnortant
readiness asset slablllly, therefore reducing
management IS considered as
a can
are mamteaance, rc:tllIbtsllme~111
Chapter3:Conceptual Phase
Maintenance is the basis for monitoring and realising the assets useful life. It
involves the re-installation of substation equipment to its intended condition and
performance through corrective or preventative actions [24] [48].
Refurbishment refers to the replacement of equipment in compliance with current
technical practices and desired operating performance. In substations for instance, it
will either be realised or extended in order to enhance the supply and the quality
thereof [24].
Strengthening is also known as re-engineering. It refers to the expansion or
upgrading of the substation and network to improve the capacity and the quality of
supply to the existing customer [24].
The utility classifies it assets as either primary or secondarynetwork assets. Network
reliability can be guaranteed when both the assets (primary and secondary) are
functional.
Primary substation assets comprises of overhead lines, power or instrumental
transformers, high or low voltage switchgear and cables. Most of the primary
substation assets are outdoor equipments and therefore needto operate under extreme
weather conditions and operate effectivelyand efficiently. Theseassets are the direct
energy delivery equipment and their failure will often lead to a disruption of the
network.
Secondary substation assets include the telecommunication, powersystems protection
relays, metering and control infrastructure. These are mainly indoor equipment and
are responsible for functionalities such as retrieving data from the network for billing
purposes.
Page 29
Chapterl : Conceptual Phase
The utility's existing structure does not support asset management and has a poor
integration between its plann ing and refurbishment sectors. There is a requirement for
a formal risk management struc ture and specialised skills and resources. It can be
concluded that asset management is a systematic process to effectively manage cost,
opera tions, maintenance of assets.
Ta ble 1 illustrates the phases involved in asse t management programme and the
implementation of asset management in Eskom Distribution. It assists in identifying
the gaps between PAS 55 and what is done at Eskom. PAS 55 is the Pub licly
Available Specification publ ished by the Briti sh Standards Institution for asset
management [32].
Table t: Eskom Distribut ion asset management programme (2) (49].
Asses ment DeslltD Pilot Implementation PhasePhase I Phase (( Phase III IVAssessment of Eskom Ox
Recommendation Solutions Pilot Implementatlen Full Rolloutvs,
for Ide ntified gaps of Asset Managem~ntImpl ementa tion of Alld
PAS 55 Manal!ementGaps identified: • Refocus Dx 10 be an asse t • Pilot improved • Roll out improved
• No AM Policy andStrategy, centric organisation, processes in 3 Eskom processes across Eskom
• Competency, Staff Retention • Establish an AM Framework Distribution Regions. Distribution
and Training is lacking, - prlKCSSCS andprocedures.
• Risk Management is not • Integrate AM Risk with
integrated intothebusiness Eskom process,
· Substation Maintenance
• Planning,
· Project engineering
• Project management
3.7 CO NCLUSION
Chapter two was the co nceptual phase of the research. This chapter inc luded the
literature study required for the research. The life cycle management plan was
discussed and then finally the life cycle management plan used in the utility was
co nsidered, The fo llowing chapter is the implementation stage of the research. It will
cove r the study of power transformers in terms of life cyclemanagement.
Page30
Chapter4: Case study-power transformers
CHAPTER 4 - CASE STUDY - POWER TRANSFORMERS
4.1 INTRODUCTION
Transformers are the most important yet expensive piece of equipment found in a
substation. Due to this, transformers require specialised skills and knowledge to
monitor and maintain. Power transformer's life cycle plan must be developed since it
is in the utilities best interest to make efficient use of transformers without creating
operational and maintenance problems.
4.2 THE RECOMMENDED LIFE CYCLE MANAGEMENT OF POWER
TRANSFORMERS
Power transformers are static equipment, their failure rate is very low compared to
other assets found in substations but because they are bulky, they require more time
and special arrangements should there be a failure [24]. The utility must have
measures inplace to reduce the lead-time inprocuring and replacing transformers that
could fail.
A life cycle management plan for power transformers should be inplace to ensure that
power is supplied to customers and risk to the network is minimised. Risk analysis
and condition assessment of power transformers will be discussed as well as life cycle
decisions [22] [24] [50].
Page 31
Chapters: Casestudy-power transf o rm ers
Life cycle management for power transformers or any other assets in the e lectricity
uti lity can be described by Figure 17. It exemplifies the relationship between the
technical, economical and environmental aspects to consider when making lifecycle
decisions forpowertransfonncrs or anyother asse ts.
Decision1--...
support
Figure 17:The decisi on support mechanism oflife cycleengineering [5 1].
4.2.1. W ilY TRANSFORMERS FA IL
"Basic power transformer failure models focus on the paper insulation failures and
where the withstand strength of the paper will decrease due to heat, moisture and
oxidation" [50].
Therefore in a nutshell, transformers fai l due to the following two reasons:
• Neglect over long period of time,
• Eventscausing distres s to transformers components.
Page 32
Chapters : Casestudy-power transformers
Cellulose insulation is a major component in a transformer. Cellulose has several
hundreds times the affinity for moisture that oil [31]. Therefore, once moisture is in
the transformer, most of it ends lip in the cellulose insulation. Figure 18 was taken to
illustrate the ac tivepart of a transformer which contains windings that are covered in
ce llulose.
Figure 18: Active part of a transformer,
Page 33
Chapter4: Case study-power transformers
4.2.2. RISK ANALYSIS OF POWER TRANSFORMERS
Asset risk management is a vital part of life cycle management for utilities that are
asset centric. It involves identifying your risk exposure and being able to manage it.
We define risk as the sum of likelihood of a failure occurring multiplied by the
consequence thereof [47].
Risk assessment for a particular asset isthe process used to analyse the probability as
well as the potential impact of an identified risk. This will enable the determination
ofthe size ofthe risk and the mitigation options thereof.
Table 2 provides the risk analysis for transformers conducted during the research for
this dissertation. This information was composed at Rotek Engineering Company.
The risks associated with transformers can be addressed byscheduling maintenance,
analysing the failure mode or consequences of risk and contingency plan and
mitigation option to limit any outage caused by the failure.
Table 2: Transformer risk analysis.
Transformer Risk Analysis
Key risk from Consequence of risk Mldgatlon optionfailure
a) Exposures at failure to workers - flying a) Know condition! risk of explosivedebris.hot oil. fire. flash burning. failure.
1. Safety b) Exposure due to poor practises - falling b) Staff training perform a riskfromtank/bushings,confined spaceentry. assessment for all tasks
c) Fire resistance fluids in some casesa) Majoroil loss on burst tank a) Inspection and rectificationb) Generaloil leaks b) Granules or synthetic mats
2. Environmentalc) Fire!burning oiVPCB c) Bund wall or oil separatorsd) In-service noise d) Firprotection system
e) Firtraining staff0 Noise enclosure
a) Loss of supply - impact on the Risk management to get endorsementperformancemeasures ofa utility andcorrective action.
b) It is a legal requirement for utilities to have3. Strategic a risk management plan - Regulators will
penalise.c) Poor press - on share price if poor
performance.a) Induced outages -loss ofavailability a) Understand failures caused andb) Losof un-depreciated capital value probabilities.c) Need for unplanned capital spend for b) Asset health reviews - to identify
4. Financial replacement likelihoodd) Possible loss of earnings on contracted c) Effective failurerecovery policy.
supply
Page 34
Chapter4: Casestudy-power transformers
Failure mode describes the manner in which something fails. The effects analysis
refers to study of the consequences of those failures. The purpose of the
FMEA (failure mode effect and analysis) is to take actions to eliminate or reduce
failures, starting with the highest-priority ones. The analysis can be done either in a
qualitatively orquantitatively way [25] [52] [53] [54].
A failure mode effect analysis for transformers was conducted atRotek Engineering
Company. The results are illustrated in Table 3. A detailed FMEA can be found in
Appendix B. Performing the failure mode and effect analysis can assistwith ensuring
that theoperational reliability of thetransformers is always up todate.
Table 3: Failure Mode effect and analysis forpower transformers.
ID Main Function Failure Mode Failure FailureEquipment of Fundlon Event Cause
1 Core Wears Loss of Mechanical failure DCMagnetisationMagnetic field efficiency
Construction fault,
Mechanical over voltage,
2 Windings ConductingShort Circuit damage, fault in movement of
current transformer, hot spots,insulation material. and generation ofcoppersulphide.
Enclose oil, Mechanical damage,3 Tank protect active Leakage Tankdamage materialmethod.part.
Mechanical Movement of
4Solid Isolation Insulation of Cannot supply damage, fault in
transformer, short(cellulose) the windings insulation circuit, hot spots,insulation material. ageingcellulose,
Particles in oil, water
Isolate, cool Short circuit in Conducting in oil, too hot5 Oil active part
transformer, particles inoil, oil air/water, oiloverheated is notcooled. circulation out of
function.
Isolate Fault isolation Dirt, water penetration,6 Bushing between tank Short Circuit material, damage carelesshandling.and windings on bushing
Regulate the Cannot changeMechanical
7 TapSelector the voltage Wearvoltage level level damage,
Maintain a8 Diverter switch coherent Short circuit Contact failure Contamination ofoil
current
Page 35
Chapter4:Case study-power transformers
Operational reliability is concerned with the following [54] [55]:
a) Theidentification and classification of actual failures with a view to establish
theexistence of any particular failure patternsor trends,
b) What can bedone about any failure patterns thatmay emerge, and finally.
A model that can be used to do this is called the "bathtub curve". The bathtub in
Figure 19 describes the relative failure rate of an assetover time. This curve models
the cradle to grave instantaneous failure rates versus time [54] [55].
End ofUfeWear·OutIncreasing Failure Rate
Normal Life (UsefulUfe)Low 'Constant" Failure Rate
The Bathtub CurveHypothetical Failure Rate versus Time
Infant MortalityDecreasing Failure Rate
Time ~
Figure 19:The Bathtub Curve [56].
The first period of the curve is the section where we see a decreasing failure rate.
This occurs during the early life of a transformer. Theflat section is called the lowor
constantfailure rate, failures occur more ina random sequence during this time.
The last section is the point the curve starts to slope and it is the increasing failure
rate. Thishappens when transformers become old and begin to fail at an increasing
rate.
Page 36
Chapter4: Case study-power transformers
4.2.3. CONDITION ASSESSMENT OFPOWER TRANSFORMERS
The failure mode and effect analysis ofpower transformers was described above, but
it does not identify the actual condition of the transformer. The second step in the
process it to perform an inspection and testing of the asset. In some instances the
residual life of the asset can be extended and the maximum return on the investment
can be achieved.
Condition assessment conducted in order to investigate asset health and to determine
maintenance timing as part of a condition based maintenance strategy. A well
planned maintenance strategy can therefore maximise a transformer's availability,
resultingincapital investment minimisation [34].
Table 4 provides the preventive maintenance plan for transformers. This table is part
of the study conducted at Rotek Engineering. Maintenance philosophies for
transformers are vital since it ensures that the equipment will remain reliable and run
for the required time of life.
Table 4: Preventivemaintenance plan for transformers.
Title 3 Months 6 Months 12 Months Scheduled Outaee
Oil Sampling X
Gasandoiloperated relay tests X
Tapchanger surge relay tests X
Axial flow fanchecks X
General fabrication maintenance X X
Valve operating checks X X
Dehydrating breather check X
Tapchanger maintenance X
Marshalling kiosk checks X
Page 37
Chapter4: Casestudy-power transformers
For transformers, very little is seen of the internals even when the tank has been
removed. Due to that, there has to be more reliance on effective diagnostics. The
diagnosis will notbe effective if the test instruments are not as accurate as they need
to be. This will require an organisation to invest in proper test instruments for their
condition assessment plans.
4.2.4. LIFE CYCLE DECISIONS
After the risk analysis is completed and the condition assessment is finished, the next
phase is the life cycle decision phase. A transformer is expensive equipment with a
low failure rate. When dealing with transformers, the following criteria have to be
evaluated [31] [53]:
a) Whether torepair, refurbish or replace aged transformers,
b) Value of redundant and sparetransformer units,
c) Overloading versus replacement,
d) Postpone maintenance or repair by installing on-line monitoring devise.
The strategies used to make decisions can suggest that all transformers be left to
service until they fail, but the cost of unexpected failure can approximately ten times
the cost of the original transformer installation. To add on to that, the time required
for rewinding or rebuilding a power transformer can take approximately six to twelve
months [57].
With that said, the following maintenance strategies can assist in preventing
transformer failure [50]:
• Time based on line tap changer overhaul,
• Time based transformer inspection,
• Time based transformer sampling,
• Condition monitoring gas-analyses.
Page 38
4.3 RIsKMETHODOLOGY
to asset
assets
assessmetnodctegy is
It involves asset cnticaltty,
asset systems rlit't",r"nn importance to
[54]
assembled in a consistent manner
assets as transformers wilt
illustrates the asset
criticality should
a
wherenv the followina equation
replacement value,
a spectnc timetrame
cost of replacmgto
are expected topopulation of
the asset same
It is
to asset
Risk (ZAR,
x
Figure 21: Model used tocalculateassetrisk [4].
This model the factors that havean impact on asset The
predictable factors that are inthe model are:
a) The current rate
b) The way in which assets are operated and maintained,
c) in the environment to which the assets are exposed,
current asset rate can modified by
as environmental factors,
inclusion
will imnrove
asset
tollowing equation [16]
p (1 (I )
p
rate.
Chapter4: Case study-power transformers
Taking into consideration how an asset is operated and maintained will improve the
methodology of determining the probability of asset failure. The following are
aspects that an asset could endure in its operation and maintenance during its life
cycle [55] [57]:
a) Incorrect operation/maintenance due to inadequately trained staff.
b) Intentional operation above the design criteria for short periods of time due
toemergency conditions.
c) Unintentional operation above the asset's design criteria due to lack of
information.
Table 5 provides a method of assessing the risks associated with operation and
maintenance of anasset. From the assessment question in this table a score between
one andthree can be obtained.
Table 5: Assessing the risks associated with operation and maintenance ofan asset [4] [59].
Operation and Maintenance Risk Contributors ScorlOI!Catezorv No. Assessment ouestlon All Some None
1Are the relevant employees suitably qualified to
1 2 3perform the required operationsI maintenance?
2Have the relevant employees been adequately trained to
1 2 3Operational I operate the assets?maintenance stalT
3 Do the relevant employees have the necessaryt 2 3experienceandtraining experience to correctly operate I maintain the assets?
Do the employees have access to and arethey familiar4 with the relevant supporting documentation (e.g. t 2 3
operational guidelines, maintenanceprocedures etc.)
5Does the Control Centre have a record of the design t 2 3parameters of the asset?
6 Do the relevant operational I maintenance employees t 2 3Operation within
know what thedesign parametersof the asset are?
designed parametera Do all employees concerned have a common7 understanding of how operation outside the design t 2 3
parameters alTect theasset's health andasset life?
8Are records being kept of when and howlong theasset
t 2 3is operated outside itsdesigned parameters?
Table 5 contains eight questions that assist in assessing the risk contributors in the
operation and maintenance of assets. These assessmentquestions are categorised into
two groups; OpcrationallMaintenance staff experience and training as well as
operation within designed parameters.
Page 41
Chapters: Case study-power transformers
The response to the assessment questions in Table 5 will yield a numerical score that
will be used to determine the risk contribution. The minimum attainable score is 8
and the maximum score is 24. Table 6 provides an analysis of the risk contribution
from thescoring results obtained inTable 5.
Table 6: Operational and MaintenanceRisk Contribution [4][55].
Scoring O&M% Contribution to Current Asset Failure RateResult Rating
8-12 1 Negligible 0%
13-16 2 Low 5%
17-20 3 Average 10%
21-24 4 High 20%
4.3.1. ENVIRONMENTAL FACTORS
The environment in which an asset is operated and maintained must be taken into
consideration. The impact from external factors within the operating environment
plays a role in determining the probability of asset failure. These extemalfactors
within an operating environment can be natural events, theft or vandalism. Table 7
provides a list of environmental factors that considered being significant contributors
to asset failure.
Table 7: Environmental factors included in the Risk Model [4] [55] [59].
OperatingNo Environment Assessment criteria
Factor
1 Lightning Probability that lightning will cause failure, based onthe asset type and thelizhtninz densitv for the immediate lleOllfaDhical area.
2 Wind Probability thatwind will cause failure, based ontheasset type, and maximumwind speed.
3 Snow and hail Probability that snow and hail will cause failure, based on the asset type andfreauencv of snow and hail storms.
4 Flooding ProbabiIi ty that flooding will cause failure, based on the asset type andfrequency of flooding occurrence.Probability that pollution (inclusive of corrosive pollution and other polluting
5 Pollution deposits causing flash-over and other events) will cause failure, based on theasset tvne and R!ude ofDollution in theimmediate vicinity.
6 Vandalism I theft Likelihood of vandalism I theft causing failure, based on the asset type, andfrequency of vandalism I theftoccurrins in the vicinity ofthe asset.
Page 42
Chapter4: Case study-power transformers
4.4 CONCLUSION
This chapter was the theoretical implementation phase of the research. It focused on
the life cycle management for power transformers. The different stages of the
transformer life cycle were analysed and discussed.
The next chapter is the conclusion of this dissertation. This chapter will provide the
shortcomings of this dissertation, recommendations and proposed further work to be
conducted.
Page 43
Chapters: Conclusion
CHAPTER 5 - CONCLUSION
5.1 INTRODUCTION
The fifth and final chapter of this dissertation will provide asummary and conclusion.
From the study and case study of this dissertation recommendations will be made and
a discussion ofshortcomings is provided.
5.2 GENERAL CONCLUSION
A life cycle approach enables product designers, service providers, government agents
and individuals to make choices for the longer term and with consideration of all
environmental media. Life cycle approaches avoid shifting problems from one life
cycle stage to another. It is therefore an ideal way ofmanaging an electric utility such
as Eskom.
The study was a success and can be investigated in depth with a more detailed
assessment on the technical side. There was however no success with the
development of a complete asset management plan which complies with PAS 55
(Publicly Available Specification) published by the British Standards Institution for
asset management.
This was partly due to the electricity utility's need to be audited and accredited with
PAS 55 which is in progress. There iscurrently a two year pilot project at Eskom to
incorporated asset management in their business. This project will assist in
completing this study.
Page 44
Chapter5: Conclusion
5.3 PROPOSED FURTHER WORK
The aim of this dissertation was to investigate methods that electricity utilities use in
order to implement asset life cycle management. There are a number of shortcomings
that were identified in this dissertation. Some of the areas proposed for further work
includethefollowing:
a. Investigating the impact of the human factor in asset management.
The human factor was not discussed inthis research but should be part of any further
work. People have an impact on themaintenance systems and the management of any
organisational strategies.
b. Investigate how life cycle costing affects asset management from the
acquisition phase to the utilisation phase.
Improving reliability of equipment is a topic that was discussed but not in detail.
There are several tools used by utilities to assist with life cycle costing. The
investigation into the methods and procedures used in a project, product and system
life cycle can be included in further work.
c. Investigating and improving the maintenance loop.
The utility's current structure does not support asset management since there is no
formal risk management structure, poor integration between planning and
refurbishment. There are limited specialists and resources as well as poor
maintenance skills withinthe utility.
It is recommended that the utility must manage its risk across the asset life cycle
stages. This should be conducted in compliance with PAS 55 in order for the utility
to be fully asset centric. This includes the establishment of a department within the
utility thatmanages assets in the business.
Page 45
Chapter5: Conclusion
This department should be made upof the following sections:
• Life cycle cost management of the assetsused,
• Risk management for assets and the network,
• Training and development,
• Project planning and management
• Maintenance management, and
• Communication.
Typically found inother life cycle managements plans, is that the end user does not
correctlyutilise the strategic measures and standards in place. It is recommended that
training, awareness and the importance of systematicalIy executing the plan will
ensure thatthe life cyclemanagementplans will be effective.
In the conclusion of the dissertation: It is recommended that Eskom Distribution
considers the implementation of recommendations mentioned in this dissertation.
This will result inamajor cost saving for the organisation.
Page 46
111111
ApPENDICES
APPENDIX B: POWER TRANSFORMER FMEA
Power Transformer FMEA 1311 ISO) (54) ISS)
1. COMPONENT DESCRIPTION: CORE
Function of Component Functional Failure Failure Mode Failure Effect Root Cause Monitoring
A. Fail to efficientlyI.Efficient Magnetic link I.Vibration monilOring,2.FRA
magnetically link the 1.Core Bracing failure I.Delamination Poor workmanshipbetween the Windings
windings(future Technology)
2.Clamping arrangementShort Circuit
loose
3.Clamping over stressed Design failure
4.Broken Welding
5.Transfonner Noise Ditto
1.lnsu1ation failure
between the core
2.Core down to earth 1.Ditto clamp. bolts and I.DGA
p1ates(Chemical and
dielectric)
2.LocaIised heating
3.Gassing
Excessive eddy
3.Lamination Insulation failure 1.Ditto current resulting in 1.DGA
overheating
2.Localised heating
3.Gassing
4.Corrosion I.Dilto oil sample
2.LocaIised heating
Page48
ApPENDICES
2. COMPONENT DESCRIPTION: WINDING
Function of Component Functional Failure Failure Mode Failure Effect Root Cause Monitoring
I.Efficiently Transfonn A. Fail to transform voltage!I.Collapsed windings I. Short circui L I.Extema1 short circuit DGA
voltage! conduct current conduct current
2.Bracing Failure
3. Intertum fault
2.GassingI.Manufacturer or design
or repair defect (dry-out)
2.1ntertum winding faultI. TOY (no Arresters or
All oil testsI.Short circuitincorrect placement).
2. Insulation failure due to
moisture
3. Insulation failure due to
short circuit
4. Insulation failure due to
quality ofoil
2. Deformation of winding. I.Ditto
3.Winding harness I.Short circuit I.Loose connections Impulse test
2.Clearances (leads and
Tank/Core frame)
3.Clearances (leads
between themselves)
4.Clearances(Leads
among phases)
Page49
ApPENDICES
l.POOR
2.Open circuitlbreak in continuity CONNEcrIONS(CRIMP DGA
lNG/SOLDERING
4. Paper degradation I.Mechanical I.Short circuit FuranicIDPIDGA
2.Heat
2.Chemical I.Moisture Oil Tests
2.Acidity
3.0xygen
3. COMPONENT DESCRImON: MAIN TANK(lndudes Gaskets Rings, valves, FlasbSbields)
Function of Component Functional Failure Fallure Mode Failure Effect Root Cause Monitoring
l.Protect inside contentsA. Moisture in oil I.Leaks I.Environmental l.Skill
against Undesirable elements
2.Workmanship
3.Non-standard parts
2.Corrosion
3.MechanicalI.Manhandle,transportatio
impact recorders, job observationsn.rigging skill
4.Gasket failure I.SkillNew units must be re-torqued again
after 3 months
2.Workmanship
3.Non-standard parts
2.Structura1ly SUpport Inside A. Failure to structurally Impact recorders, Monitoring,I.Mechanical (bolts breaking) I.Location boltsIBrackets broken I.Manhandling(rigging)
parts support inside parts inspection
2.Earth tremors
Page 50
ApPENDICES
3.Short circuits
3.Structurally support A. Failure to stJUeturally I.WateraceumulationI.Corrosion l.Brackets/bolts Visual inspections
Outside pans support outside pans through poor design
2.Sub-standard corrosion
protection
2.Pipework l.Poor clamping
2.Mechanical I.Location bolts/Brackets broken 1.M.anhandling(rigging)
2.Eanh tremors
3.SbOrt circuits
2.Lifting lugs/jacking points 1.Manhandling(rigging)
A. Fail 10 confine Oil inside4.Confme oil inside the tank l.Oil leak I.Massive Tank Rupture 1.Pressure PRV
the Tank
2.Slowleak I.Conosion Visual inspection
2.Gaskets failure Visual inspection
3.Weld crack Visual inspection
Page 51
ApPENDICES
4. COMPONENT DESCRIPTION: OIL(UQUID INSULATION)
Function of Component Functional Failure Failure Mode Failure Effect Root Cause Monitoring
1.1 Ingress ofA. Fail to insulate (Dielectric l.Water contamination - Internal flash-
I.lnsulation I.lntemal fault(Flash over) water/moisture(No Oil sampling!Failure) over(PPM)
effective sealing)
2.Free particles l.Intemal fault(Flash over) Workmanship Oil sampling!
2. Provide Effective Cooling A. Fail to provide effectiveI.Sludge I.Poor circulation Blocking ofoil ducts Oil analysislVisuall
to the Transformer Cooling
3.Protc:c:t insulation material A. Fail to protect I.insulation breakdown I.Deterioration ofoil quality Dielectric strength oil samples
DP test, funaric test
50COMPONENT DESCRIPTION: PAPER(SOUD INSULATION)
Function of Component Functional Failure Failure Mode Failure Effect Root Cause Monitoring
I.Degradation due tol.Insulation material A. Fail to insulate I.Chemical I.Flashover Oil tests, Tan Delta tests
moisture, heat, oxygen
2.Electrical I.Flashover I.TOV's Surge arrestors
3.Mc:c:hanical I.Flashover I.Short circuit FRA
2.Distortion I.Manhandling Impact recorders.
6. COMPONENT DESCRIPTION: CONSEVATOR TANK(iDc:lude piping)
Function of Component Functional Failure Failure Mode(Why) Failure Effect(What) Root Cause Monitoring
A. Fail to act as an OilWorkmanship(rags,closed
l. Oil Reservoir l.Blockage in the pipe l.Oil flow restriction valve,Seal paper left on inspectionsreservoir
silica gel cartridge,)
Moisture.Corrosion2.Corrosion 1.00lieak visual inspections
protection
Broken oil level indicator visual inspections
Page52
ApPENDICES
2.Transport Oil(pipe) A. Fail to transport Oil l.Welding cracks l.Oilleak. Manhandling visual inspections
Moisture, Corrosion2.Corrosion l.Oilleak visual inspections
protection
3.Breathing(pipe) A. Fail to breath l.Welding cracks l.Oilleak Manhandling visual inspections
Moisture, Corrosion2.Corrosion I.Oilleak visual inspections
protection
Moisture, Corrosion4.Support buchboltz(pipe) A. Fail to support buchholz I.Corrosion l.Oilleak. visual inspections
protection
Page 53
ApPENDICES
7. COMPONENT DESCRIPTION: RADIATOR
Function of Component Functional Failure Failure Mode Failure Effect Root Cause Monitoring
I. Provide Effective CoolingA. Restricted oil flow l.Blocked radiators l.Heating
to the Transfonner(oil flow)Sludge oil samples
butterfly valve closed Visual inspection, Infrared scanning
Damaged fins Visual inspection,
2. Provide Effective CoolingA. Restricted air flow I.External blockage I.Heating
Foreign(nests,vegetation,eVisual inspection,
to the Transformer(air flow) te) blockage
3. Provide Effective Cooling
to the A. Reduced emissivity( I.Cover with low emissivity coating l.Heating Pollution Visual inspection,
Transformer(Emission)
8. COMPONENT DESCRIPTION: BUSWNGS Oncludes conductor Connections)
Function of Component Functional Failure Failure Mode Failure Effect Root Cause Monitoring
l.Provide path from externalLightning,(to be moved to
conductor to internal A. Fail to insulate 1. External flash-over
conductor (insulate)windings)
Pollution Visual inspection
ForeignVisual inspection
objects(birds,monkeys)
2. Capacitance insulation fail - causing I.Explosion of bushing + oil spillMoisture, partial discharge Tan delta test
electrical fault (possilble fire)
Test-pin connectionllead
damagedTan delta test(capacitance value low)
3.Moisture ingress I.Explosion of bushing + oil spill Seal tap insulation test
Page 54
ApPENDICES
(possilble fire)
Sub-standard material Quality checks on Manufacturers
Poor workmanship Quality checks on Suppliers
4. Porcelain damage-Explosion of bushing + oil spill
VandalismlFlash over Visual inpection(possilble fire)
Damage by adjacentVisual inspection
equipment failure
Flash-over Vandalism Visual inspection
Damage by adjacentVisual inspection
equipment failure
2.Provide path from external Poor
conductor to internal A. Fail to conduct I. Loose connection- hot connection worlonanship(Crimp.Swea Infra red
conductor (conduct) t.Bolt)
Visual inspection
A. Fail to contain oil (fallI. Grouting degradation-crack Oil spill evident Poor material Quality checks on suppliers3.Contain Oil
under FCI)
Canti lever loading Visual
2. O-ring I gasket/Grommet failure Oil spill evident Poor material
Canti lever loading
3. Gauge glass leak. Oil spill evident Poor workmanship Observations
4.Porcelain crack Oil spill evident Poor worlananship Observations
Poor design(Conductors5.Cantilever loading Oil leak Quality checks on design
supported by bushings)
Vandalism Visual
Canti lever loading Visual
9. COMPONENT DESCRIPTION: BUCHHOLTZ
Page 55
ApPENDICES
Function of Component Functional Failure Failure Mode Failure Effect Root Cause Monitoring
I.vibration 2.materiaIl.Provide Alann pulse A. Fail to provide alann 1. Switch fail (Mercury or Reed) I.No immediate noticeable effect visual inspection during maintenance
fatigue
2. failure of internal mechanism or LNo immediate noticeable effect Lvibration 2.materiaI
float 2.sustained alarm fatiguevisual inspection during maintenance
pet cock assembly/pipe3.fail to contain gas gases escaping
leakingvisual inspection during maintenance
1.vibration 2.material2.Provide Trip pulse A. Fail to provide trip I. Switch fail (Mercury or Reed) l.No immediate noticeable effect visual inspection during maintenance
fatigue
2. failure of internal mechanism or I.No immediate noticeable effect 1.vibration 2.material
float 2.sustained trip or no tripping fatiguevisual inspection during maintenance
manhandling(installation)
2.material3.Contain Oil A. Fail to contain oil L Inspection glass/plastic crack 2. LOil spill visible 10 operator visual inspection during maintenance
incompatibility(perspex
used )
Manhandling (installation)
2.gasket damage/perished I.Oil spill visible to operator 2.age 3. Material visual inspection during maintenance
incompatibility
3.Leak at sampling valve I test valve I.Oil spill visible to operatorManhandling (installation)
visual inspection during maintenance2.age (o-ringlseal) 3.
Page 56
APPENDICES
10. COMPONENT DESCRIPTION: COOUNG SYSTEMS (FANS)
Function of Component Functional Failure Failure Mode Failure Effect Root Cause Monitoring
A. Fail to cool the l.transfonner temperature mechanical/electricalI.Cool the Transformer I.motor not working visual inspections
transformer increasing(otilwti) (many)
I.transfonner temperature2.broken fan blades mechanical (many) visual inspections
increasing(otilvni)
l.transformer temperature3.fan assembly broken/detached mechanicaVeovironmental visual inspections
increasing(oti/wti)
11. COMPONENT DESCRlmON: UREATHING MECHANISM
Function of Component Functional Failure Failure Mode Failure Effect Root Cause Monitoring
LOry the breathing aiI{silica l.Discolouration, noticeable toA. Fail to dry breathing air 1. Silica gel spent (no longer active) service intervals Visual inspections
gel) operator
incorrectly sized
breather(to small)Visual inspections
gaskets/sealing washers
damagedVisual inspections
container damaged Visual inspections
flanged/threaded
attachment damaged Visual inspections
/leaking
breather pipe rusted Visual inspections
conservatorl.Brown discolouration, noticeable
2. Silica gel contaminated with oil overflow(caused by trf Visual inspectionsto theoperator
internal fault/overfilling)
Visual inspections
Page 57
ApPENDICES
Visual inspections
3.Threaded/flanged arrangement fail to dry air/discoloration from theincorrect installation Visual inspections
damaged top
2. Assist with breathing A. no breathing I.silica gel pennanendy blue fail to breath silica gel car1ridgesealed Visual inspections
flanged gasket with noVisual inspections
hole
2. Breather (container) not sealing at I.Discolouration from top of
the top flange because gasket failed containermanhandling Visual inspections
materialIdesignVisual inspections
substandard
flanged/threaded
attachment Visual inspections
damagcdlleaking
breather pipe rusted Visual inspections
3. Remove particles fromA. Fail 10remove particles
l.No / low oil level, visible tooil bowl cracked/broken
air(oil bath)I. Bottom oil bath empty
operator/oil leakVisual inspections
trf surge(clear the bowl ofVisual inspections
oil)
poor workmanship Visual inspections
incorrect
installation/vertical
12. COMPONENT DESCRlmON: TAP CHANGER
Fuacdoa ofCompoacat Fuacdoaal Failure Failure Mode Failure Effect Root Call5e Moaitoriag
l.Profdes gearing (gearingA. fail to provide gearing Visual Inspection (Done ofT
ratios between motor and I.Geneva sheared pin In-correct/no selection Mechanical fatigueand selection loadyrests
tap change
Page 58
ApPENDICES
(Selcetor!Di\'Crter) s",itehcs
(Tap change mechanism)
Visual lnspcction (Done ofT2.Sheared shaft In-correct/no selection Mechanical fatigue
load)ffests
Visual Inspection (Done ofT3.Damaged gears In-correct/no selection Mechanical fatigue
loadyreslS
2.Selccts appropriateA. Fail to select appropriate
tJp
position off·load during tJptap position off·load during I.Uncotrolled tap positioning(Oul of
In-com:ctloo selection Tap ",inding damage Tap changer test (Speed lest!UV leSt)
changing(SelcctOl' switch)tap cbanging(Selcctor alignment)
S""ilch)
3.Divuts c:urn:Dt on load
during lap changing(Di\-ater A.. Fail to divert I.Tap change failure Burning of Resistor
switch)
2.Sequence 001 of line
l..mechanical failure
during sdCClOr/divcner
".Limit" the flow_ilching(l.e.slow
aun:nIl.winding damage 2.cxcessivc switehing.brok.en
during tramitioo(TransitiOll A.. fail to limit I.resistor damagc(pan1y shorted out) Conditioo monitoringcontact wear pins/geneva wheels/fly
resistor)",mel and spring andIOI'
charging assembly broken
)
1.mccbanica1 failurel.winding damage 2.excessi\"c
2.resislOr open circuit(more common) during sdcetor/divcner Conditioo monitoringcontact wear
swilching(Le. slow
Page59
ApPENDICES
switching, broken
pins/geneva wheels/fly
wheel and spring and/or
charging assembly broken
)
5.Detect any over pressure ( A. Fail to detect overCable gland seal not
Tap change pressure pressure in the diverter I.Diaphragm damage No trip/in correct tripproper/Cover seal
relay(Component» compartment
Cable gland seal not2.Spring damaged No trip/in correct trip
proper/Cover seal
Cable gland seal not3.Corrosion No trip/in correct trip Visual inspection/Calibration Test
proper/Cover seal
6.Deteet any surge ( TapA. Fail to detect surges in the Cable gland seal not
change surge I.Corrosion No trip/in correct trip Visual inspection/Calibration Test
relay(Component»diverter compartment proper/Cover seal
2.In correct calibration No trip/in correct trip In correct Installation Calibration
7.Conduct current( Moving excessive mechanical and/or1. Misalignment 2.contact
Condition monitoringlVisualloiIA. fail to conduct l.no contact! insufficient contact assembly damaged
contacts) electrical wear sampling3.substandard materials. 4.
excessive mechanical and/or2.Material fatigue
electrical wear
1. Misalignment 2.contact
Arcing assembly damaged
3.substandard materials. 4.
heat /current flow due to3.Coking ofcontact carbonising ofcontact Visual
lack of tap movement
Page 60
ApPENDICES
8.Conduet current( Fixed excessive mechanical and/orI. Misalignment 2.contact
Condition monitoringlVisua1loilA. fail to conduct I.no contact! insufficient contact assembly damaged
contacts) electrical wear sampling3.substandard materials. 4.
excessive mec:hanic:al and/or2.Material fatigue
electrical wear
I. Misalignment 2.contact
Arcing assembly damaged
3.substandard materials. 4.
heat fcurrent flow due to3.Coking ofcontact carbonising ofcontact Visual
lackoftap movement
9.Keep tap changer oilA. Fail to keep oil separate I.mechanical fatigue,
separate from main tank l.craking leaking oil samplebetween electrical failure.3.sealing
oil(Barrier board)
1.overtension,2.Substanda2.bobbin failure leaking visuals, training
rd material
13. COMPONENT DESCRIPTION: l\Iecbanleal boxIMotor drive
Function orComponcnt Functional Failure Failure Mode FaUure Effect RootCausc Monitoring
I.Stores energy A. Fail to store energy Broken Springs I.No charging of flywheel
2.Bumt motor, Broken fan belt
3.lnterlock switch for manualLack ofskiU visual
o~tingnotwor1<ing
2.Wipe contact A. Wiping contact failure corroded wiping contacts I.Heater not working
2.Wiping not done after transformervisual,condition monitoring
is stationery for a long period
3.Heater A. Fail to keepmoisture out I.Not connected Corrosion frust visualinspection
2.Nopower
3.Broken wires
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ApPENDICES
4.Seals A. Fail to keepmoisture out l.Rust No inspection done Neglect visual inspection
2.Moisture
S.Limit switches(wipingA. Fail to keepwithin limits Fail to store energy Cause manual reset Condition monitoring
contacts)
6.Linkage betweenA. Fail to link Mechanical
Mechanical box and Selector 1. Broken Shaft No tap changing visual inspectionBox and Selector
(MRBox)
2.No settings done when changingTraining of Staff visual inspection
Mechanical boxes
14. COMPONENT DESCRIPTION: PRVIEXPLOSION VENT(BELCH PIPE)
Function of Component Functional Failure Failure Mode Failure Effect Root Cause Monitoring
I Act as a pressure relief for incorrect installationA. fail to relieve oil pressure I.incorrectly sized prv damage to transformer Visual
the main tank lmaintenance
2.incorrectly sized/type diaphragm in incorrect installationdamage to transformer Visual
explosion vent lmaintenance
2.Pressure release at A. pressure released too incorrect installationt.spring not applying correct pressure oil leak Visual
appropriate time quickly lmaintenance
incorrect installation2.sealing arrangement damaged oil leak Visual
lmaintenance
A. internal faults/external
3.incorrectly sized prv oil leak faults, oil head, incorrect Visual
installation lmaintenance
A. internal faults/external4.incorrectiy sized/type diaphragm in
oil leak faults, oil head, incorrect Visualexplosion vent
installation lmaintenance
S.incorrect filling ofoil oil leak poor work practice Visual
6.incorrect transportation oil leak poor work practice Visual
Page 62
ApPENDICES
I I I I I15. COMPONENT DESCRIPTION: TEMPERATURE GAUGES(OIL AND WINDING)
Function ofComponent Functional Failure Failure Mode Failure Effect Root Cause Monitoring
1.wor1<manship(Training),
Fail I. No/lncorrect readings2.Corrosion (Gauge seal,
to measure temp.Measure temperature(Oil) I.BrokenlMissing capillary tube Cable Visual, Testing/Calibration
laccurate temp. 2.Nuissance alannsltrippingglancing),3.Capil1aIy tube
sealing)
l.workmanship(Training),
2.Capillary pockets full of 1. NolIncorrect readings2.Corrosion (Gauge seal,
Cable Visual, Testing/Calibrationwater/solvent 2.Nuissance alannsltripping
glancing),3.Capil1aIy tube
sealing)
I.workmanship{Training),
1. NolIncorrect readings2.Corrosion (Gauge seal,
3.Capillary pocket Empty ofoil Cable Visual, Testing/Calibration2.Nuissance alannsltripping
glancing),3.Capil1aIy tube
sealing)
I.workmanship(Training),
4.Instrumentlmechanism I. NoIIncorrect readings2.Corrosion (Gauge seal,
Cable Visual, Testing/Calibrationdamaged/corroded 2.Nuissance alannsltripping
glancing),3.Capil1aIy tube
sealing)
l.workmanship(Training),
Measure Fail to measure temp. 1. NoIIncorrect readings 2.Corrosion (Gauge seal,
tcmperature(Winding) /accurate temp.I.BrokenlMissing capillary tube
2.Nuissance alannsItripping CableVisual, Testing/Calibration
glancing),3.Capil1aIy tube
Page 63
ApPENDICES
sealing)
2.Capillary pockets full of I. NoIIncorrect readingsditto Visual. Testing/Calibration
water/solvent 2.Nuissance alarmsItripping
I. NoIIncorrect readings3.Capil\ary pocket Empty ofoil ditto Visual. Testing/Calibration
2.Nuissance alarmsItripping
4.lnstturnenl/mechanism I. NoIIncorrect readingsdiuo Visual, Testing/Calibration
damaged/corroded 2.Nuissance alarms/tripping
I S.CT/resistor damageI. No/lncorrect readings 2.No or
CorrossioaResistor), Testing.incorrect alarms/tripping
16. COMPONENT DESCRIPTION: SURGE ARRESTORS
FallCdoa 01 COlllpOllftil F..cdo.... Fallarc Failure Mode Fallarc Erred a-Caase MoaitoriD&
I.incorrect applieatiool.Protectioo of main I.equipment failure(noticeable) and totaL'partial destruction, no
A. Fail to protect 2.TOV \isua1, Testing(SpecW equipment)equipment (TrmsfonDCf) unnoticeable noticeable effect
3.Pollution.4.Vanda1ism
S.DOa applkatioa or
GradiD& riDe ..-baa
rrqllired
17. CU\IPONENT DESCRlmOl'lf: OILLEVEL INDICATOR
Faactioa or COlllpOllC1l1 FuctioaaJ Fallan Failun Mode Fallun Effed RoolCatie MoalloriD&
Page 64
ApPENDICES
Polluted gauge, workman
ship, sub standardI.Measure oil level A. fail to measure I.broken gauge,(Linear type) Trftrip on low oil visual
material. contaminants in
oil(linear oil gauge)
Wrong indication
Broken gauge glass can cause oil
leak
2.broken gauge,(dial type) Trf trip on low oilCracking/filling
visualuplbreaking of float
Broken gauge glass can cause oilBending of floatarm visual
leak
Wrong indicationfloat gearing mechanism
visualbroken
Dial indicator glassvisual
broken
Corrosion(Gauge covervisual
seal)
oil leak due to shaft seal visual
Page65
ApPENDICES
18. COMPONENT DESCRIPTION: EARTIUNG
FUDetioDof COmpoDCDt FUDctiooaJ Failure Failure Modc Failure Effcct Reet Caase MOnitOriDg
I.Provide effective step and touch potential will beA. fail to provide Loose connection workman ship Visual! Test (earth cont.)
eanhling(Protection) affected
No continuity to earth mat
Theftstep and touch potential will be
theft Visualffest (earth cont.)affected
No continuity to earth mat
Non standard earthing used bum offduring fault currents workmanship Visual
Copper and galvanized steel(1int
marts)
19.COMPONENT DESCRlmON: OIL PUMPS
FUDctioDor COmpoDtDt FunctioDai Failure Failure Modt Failure Efftct RootCaase Monitoring
faulty pump,2.faulty
I.circulate oil A.fail to circulate oildifference in oil temperature within a
over heat leading to tripwindingfoil temp.
tank gauge.3.No supply to oilVisual, Electrical test
pwnp.4.Pump motor fault
10. COMPONENT DESCRIPTION: MIB's(SpUt betweeD F'S and EDF'S)
Fuactioa or Compoacut FaoctioDal Failure Failure Mode Failure Effect RootCaase Monitoring
Page 66
ApPENDICES
l.Contain
proccc:tioG'mctcring ICT A.fail to contain I.Loose cable glands open circuit OIl ITs Wor\:manship Visual
cable COIlIlCCtions
2.Conncctioas nol tighlc:Dcd Rain waler ingress into boxesNo effective sealing at
doors
3.COITOSion Ingress of insects(Dirt)
unnecessary Trips due to4.Moistures,
water(Rain)
5.Blockcd air vents,
6.Thcft
Page 67
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