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8/13/2019 Module III - Concepts and Principles of Distribution Loss
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DRUM TRAINING PROGRAMA U.S. Agency for International Development (USAID)
Funded Program
BEST PRACTICES INDISTRIBUTION LOSS REDUCTION
Program Presenter Program Presenter
National Power Training Institute CORE International, Inc.
January 27
February 1, 2005, Faridabad
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III. Concepts & Principlesof
Distribution Losses
2
M. V. S. Birinchi
CORE International, Inc.
BEST PRACTICES IN
DISTRIBUTION LOSS REDUCTION
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Losses
Technical losses
Commercial losses T & D losses
AT & C losses
Concepts & Principles of Distribution Losses
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Technical Losses Every element in a power system
a line a transformer etc
consume some energy whileperforming their expected duty.
Cumulative energy consumed byall these elements constitutes
technical losses
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Commercial Losses
Occur on account of
Non performing meters
Under performing meters Meters not read
Application of lower multiplication
factors
Defects in CT / PT circuitry
Pilferage by manipulation
Theft by Direct tapping etc.
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T & D & Revenue Loss
The total of Technical &
Commercial losses are called
T&D losses
In addition to the above,
revenue loss occurs on accountof non-realisation of billed
demand
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AT & C Losses
AT & C is abbreviation for
Aggregate Technical & Commercial
loss
Example:Units Input 100 MU
Units sold 70 MU
Losses 30 MU
T&D loss% 30%
If Revenuecollections are 90%
of demand
Out of 70 MU of
sales revenue isrealised for 63 MU
AT & C losses
are 37%
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Historical background for high losses
Developing Countries could not invest in
network expansion commensurate with
rapid load growth
Network expansion carried out onadhocism & haphazard basis
Diversity factor of 1.5 was adopted which
is now lost due to restricted supply
Usage of lower size conductor, lowvoltage pockets, absence of reactive
power control etc.
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Loss Scenario in India
Sl.
No.System Segment
Existing
Level
Target
Level
% diff
3 to 4
1 2 3 4 5
1. Trs. System 4.5 2.0 225%
2. Sub Trs. System 4.0 2.25 178%
3. Primary (HV) Distn. 7.0 3.00 233%
4. Secon (CV) Distn. 7.5 1.00 750%
5. Total 23% 8.25 279%
[Tolerable level can perhaps be 4 + 4.0 + 5 + 2 = 15%]
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Causes for Technical Losses
Lengthy Distribution (11 KV & LT) lines
11 KV & LT lines are extended for
unduly long distances in RuralAreas (low load density)
Inadequate Conductor sizes
Initially lower size conductors were
used and are not replaced whenload growth has taken place.
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Length of 11 KV line corresponding to different loads_______________________________________________________________________Size of KVA-KM for 8% Maximum of Load thatconductor voltage drop at length of can be(with 0.8 PF line connectedcode No.) (KM) (KW)
________________________________________________________________________50 MM2ACSR 10, 640 30 355
Rabbit
30 MM ACSR 7,200 20 360
Weasel
20 MM2ACSR 5,120 15 341
Squirrel
. The figures are for a conductor temperature of 60o C. For a conductor temperatureof 50oC, the above figures shall be about 3% higher and for a temperature of 70oC about 3%
lower.
Standards for 11 KV lines
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Standards for LT linesLength of 415 volts line corresponding to different loads________________________________________________________________________Size of KW-KM for 8% Maximum of Load thatconductor voltage drop at length of can be(with at 0.8 PF line connectedcode No.) (KM) (KW)________________________________________________________________________30 MM2ACSR 11.76 1.6 7.35Rabbit20 MM2ACSR 7.86 1.0 4.86Weasel13 MM2ACSR 5.58 1.0 5.58
30 MM2
AAC ANT 12.06 1.6 7.5416 MM2Gnat 6.96 1.0 6.96________________________________________________________________________The figures are for a conductor temperature of 60 C. For a conductor temperature of
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Causes for technical losses(Contd.)
Wrong location of DTRs
DTRs are not located centrally &
farthest consumers face low voltages
For every 10% voltage drop losses
increase by 21% and for every 20%
voltage drop losses increase by 44%
DTRs to be relocated at load centre to
minimise losses.
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Causes for technical losses(Contd.)
Over rated DTRs
Under loaded DTRs are a source forhigh avoidable iron losses
Taking village as a unit the loads can
be readjusted among all DTRs in the
village for optimal use of installed
capacity
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Causes for technical losses(Contd.)
Low Voltage Pockets
Where as the permissible voltage
variations are 6% the voltages atsome points go below 10% and in rare
cases even more.
Full load current drawn by motors go up
by 15% for every 10% drop in voltage On load tap changers are not made use
of due to certain inhibitions
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Causes for technical losses(Contd.)Low Power Factor
In majority of Distribution circuits the p. f
is between 0.65 & 0.75
Low p. f. contributes to high distributionlosses
When shunt capacitors of adequate rating
are fixed at load end, experiments showed
10% improvement in voltage20% reduction in current
6% overall reduction in energy.
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Causes for technical losses(Contd.)Bad workmanship
Bad joints are a source of power loss
Proper jointing techniques should beadopted for firm connection
Connections at line jumpers, Trs. bushing
rods, drop-out fuses, isolators, LT switch
etc shall be periodically inspected. Timely replacement of deteriorated
wires, worn out clamps etc
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I O S P(Integrated optimum System Planning)
An integrated approach towards optimum
system planning for prioritizing the works is as
follows
Reconfiguration Change of feed from onesource to another
Reconductoring Enhancing conductor size by
replacement or conversion to double circuit
Shunt / series capacitor (switched / unswitched) Auto Booster
Additional link lines
Combination of two or more of the above
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I O S P (Contd)
For each of the approach as above
LRVI (Loss Reduction & Voltage
Improvement) are determined
Cost benefit ratio is calculated and
least cost option for maximum LRVI is
selected.
IT IS IMPORTANT TO CONDUCTTHESE STUDIES FOR LOAD GROWTH
UPTO 5 YEAR HORIZON.
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Software packages available
Hardware Software packages available
Work Stations CADPAW, CAD PAD ABB, USA
Plotters DINIS ICL, UK
Digitisers PRAO EDF, France
Printers CYME CYME inc., CanadaScanners DPA SCOTT & SOOTT, USA
PSS Power Technologies
SINIX Siemens, Germany
DISBUT APSEB
CAPSI WIPRO
DISTPLAN CPRIPOWER NET GECE
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H. V. D. S.
High Voltage Distribution System
The HT to LT ratio is now skeweddue to very long LT network For 100 KVA load at 11 KV the
amperage is 5 Amps where as at LTit is 140 Amps.
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Conversion of existing LVDS to HVDS
Single phase HVDS and 3 phase
HVDS are both practised
As majority of existing Agl. pump sets
are with 3 phase motors, 3 phase
HVDS is more acceptable.
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Sample results of conversion toHVDS in APSPDCL
Location
Voltage Losses%
Before After Before AfterKottur 350 420 18.63 5.47
Patnam 340 420 16.82 5.30
Bangarupalem 320 430 16.30 3.77
Murakambattu 385 430 13.76 5.44
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Additional Benefits Motor Burn outs drastically gotreduced Fuse blow outs are practically NIL Reliability of supply has improvedconsiderably Consumer satisfaction has gone up.
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Steps taken to reduce commercial losses Accurate Metering Plan (appropriate range) Correct selection of C.T. ratios High and sustained accuracy meters for
high value services Intensive inspections by pooling up staff Reduce Meter exceptionals by changingdefective meters One time regularisation of unauthorisedservices
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Steps taken to improve MBC
Introduced spot billing through hand-held computers Networking of Electricity Revenueoffices cash collection centres Multiple payment options Web enabled services
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In this Training Course Exchange of experiences expertisetowards Reduction of Technical losses Reduction of commercial losses Efficiency improvement in MBC
Metering, Billing Collections. Thus reduce AT C losses.
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THANK YOU
FOR
YOUR ATTENTION
INTERACTION INVITED