Date post: | 06-May-2015 |
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Engineering |
Upload: | shanid-ahammed |
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ONLINE DETECTION AND LOCATING OF FAULTY NODES USING HF SIGNAL
INJECTION IN SMART GRIDS
Guided by,
Mr. Labeeb .M
Asst. Prof. EEE Dept.
MESCE
Submitted By,
Shanid. P
S8-EEE
10105053
MESCE
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OVERVIEW
Introduction.
Demerits of Conventional methods of fault detection.
Fault detection using High Frequency signal injection .
Basic principle
Flowchart
Conclusion
References
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INTRODUCTION
Fault in a power system is an un predictable situation that will lead to un balance in overall power system.
Common reason for establishing faulty nodes in power system network are SLG,LL,LLG faults and Electricity theft.
Detection and localization of faulty node in a power system has great importance in current scenario.
Impact on utility supply providers budget.
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INTRODUCTION (Cntd…)
Early locating of fault and restoration of supply ensure safety and reliability.
As far as quality of supply is considered detection and locating of faulty node has to be done without interrupting the supply.
HF signal injection method is most suitable for online fault detection
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DEMERITS OF CONVENTIONAL METHODES
Need high calibrated energy meters.
De- energization of Network is required.
Inability to apply on short range and multi layer networks .
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FAULT DETECTION THROUH HF SIGNAL INJECTION
An online method. Communicate between Consumer and central unit through
PLC/GSM/ZIGBEE. Use A-band signal (3-95KHz) injection.
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BASIC STRUCTURE
12N
Smart meter-
N
Smart meter-
2
Smart meter-
1
Central UnitMVLV
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SMART METER REQUIREMENTS
High bandwidth meter transducer .
Facility to ascertain basic quantities- Active power(P) Reactive power(Q) Apparent power(s) V,I and f
Communication module PLC/ ZIGBEE / GSM
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CENTRAL UNIT REQUIREMENTS
Predetermined information regarding
Number of nodes Impendence between nodes at HF
Communication module
PLC \ GSM \ ZIGBEE
High voltage coupler.
Current injection unit.
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CURRENT INJECTION UNIT
PROGRAMMABLE TEST SIGNAL GENERATOR
POWER AMP HV COUPLER
CENELEC standard EN50065-1 limits imposed voltages on nodes less than 1V
Injected current value is set based on estimated line impedance to meet the standard.
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BASIC PRINCIPLE
Load flow analysis at High frequency(HF) is done for detection an locating of faulty node
Test signal at high frequency is send to the network periodically
Load impendence are calculated at high frequency for load flow analysis Direct method Transformation method
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IMPEDENCE TRANSFORMATION
Load impedance at power frequency is converted to impdence at high frequency using load models.
ZLi Li+j 2LLLi
𝐴=𝜋 𝑟2
2irms
iLi
I
PR
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IMPEDENCE TRANSFORMATION (Contd..)
2
22
2
)(
irmsLl
iiLi
If
PSL
i=1,2,3…n𝑍 𝐿𝐻 ( 𝑓 )=𝐻 ( 𝑓 ) 𝑍𝐿
=Load impedance of node at power frequency
= Power frequency=Apparent power at node.
=Real power at node
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BASIC PRINCIPLE(Contd….)
Measured load impendence are send to central unit for load flow analysis.
Predetermined impedance between nodes are combined with load impedance at HF to form admittance matrix.
Central node develop new admittance matrix each time it get new HF load impedance from smart meter.
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BASIC PRINCIPLE(Contd….)
where i≠k
Ii=0 for Ii ≠1 for HF domain
=
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From calculated impedance matrix central unit calculate voltage at individual nodes (Vbus) using load flow analysis.
BASIC PRINCIPLE(Contd….)
= Vbus
Periodically measured node voltage due to HF signal using smart meter is stored in central unit as Vmeas matrix.
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FAULT DETECTION AND LOCALIZING
Predicted value for node voltage for test signal injection=Vbus
Node voltage measured using smart meter=Vmeas
Vdiff=Vmeas-Vbus
If there is no fault Vdiff=0
: if xVT
: if xi > xk k xi=FN
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FAULT DETECTION AND LOCALIZING (Contd…)
Graph showing fault near to node 34
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CONCLUSION
The high frequency test signal injection method can be used in live network without interfering the supply. This online fault detection and localizing method is based on the analysis of network characteristics using power flow analysis at high frequency