This document describes a method for online detection and localization of faulty nodes in smart grids using high frequency signal injection. It discusses how conventional fault detection methods require de-energization of the network or high calibrated energy meters. The proposed method injects a high frequency test signal into the network and analyzes the impedance measurements from smart meters using load flow analysis to determine the location of any faults, without disrupting the power supply. Key aspects include using smart meters to measure voltages and transmit impedance data, a central unit to calculate impedance matrices and identify faults based on voltage differences, and a current injection unit to introduce the high frequency test signal.

1. 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
1

2. OVERVIEW
 Introduction.
 Demerits of Conventional methods of fault detection.
 Fault detection using High Frequency signal injection .
 Basic principle
 Flowchart
 Conclusion
 References
2

3. 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.
3

4. 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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5. 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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6. 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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7. BASIC STRUCTURE
12N
Smart
meter-
N
Smart
meter-
2
Smart
meter-
1
Central Unit
MVLV
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8. 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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9. 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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10. 10
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.

11. 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
11

12. IMPEDENCE TRANSFORMATION
 Load impedance at power frequency is converted to impdence
at high frequency using load models.
ZLi = 𝑅Li+j 2𝜋𝑓LLLi
12
𝐴 = 𝜋𝑟2
2
irms
i
Li
I
P
R 

13. IMPEDENCE TRANSFORMATION (Contd..)
13
2
22
2
)(
irmsLl
ii
Li
If
PS
L


 i=1,2,3…n
𝑍 𝐿𝐻 𝑓 = 𝐻 𝑓 𝑍 𝐿
𝑍 𝐿𝑖=Load impedance of 𝑖 𝑡ℎ node at power frequency
𝑓𝐿= Power frequency
𝑆𝑖=Apparent power at 𝑖 𝑡ℎ
node.
𝑃𝑖=Real power at 𝑖 𝑡ℎ node

14. 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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15. BASIC PRINCIPLE(Contd….)
𝑌𝑖𝑖 = 𝑘=0
2𝑛+1
𝑌𝑖𝑘 where i≠k
Ii=0 for Ii ≠1 for HF domain
𝑌𝑖𝑘=𝑌𝑘𝑖
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16.  From calculated impedance matrix central unit calculate
voltage at individual nodes (Vbus) using load flow analysis.
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BASIC PRINCIPLE(Contd….)
= Vbus
 Periodically measured node voltage due to HF signal using
smart meter is stored in central unit as Vmeas matrix.

17. 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
∀ 𝑥 ∈ 𝑉𝑑𝑖𝑓𝑓 : if x ≥VT 𝑥 ∈ 𝐹𝑁𝐴
∀ 𝑥 ∈ 𝐹𝑁𝐴: if xi > xk k≠ 𝑖 xi=FN
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18. FAULT DETECTION AND LOCALIZING
(Contd…)
18
Graph showing fault near to node 34

19. 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
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