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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