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Online detection and locating of faulty nodes using


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High frequncy signal injection based faulty node locating in smart gris

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Online detection and locating of faulty nodes using

  2. 2. OVERVIEW  Introduction.  Demerits of Conventional methods of fault detection.  Fault detection using High Frequency signal injection .  Basic principle  Flowchart  Conclusion  References 2
  3. 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. 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 4
  5. 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 . 5
  6. 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. 6
  7. 7. BASIC STRUCTURE 12N Smart meter- N Smart meter- 2 Smart meter- 1 Central Unit MVLV 7
  8. 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 8
  9. 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. 9
  10. 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. 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. 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. 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. 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. 14
  15. 15. BASIC PRINCIPLE(Contd….) 𝑌𝑖𝑖 = 𝑘=0 2𝑛+1 𝑌𝑖𝑘 where i≠k Ii=0 for Ii ≠1 for HF domain 𝑌𝑖𝑘=𝑌𝑘𝑖 15
  16. 16.  From calculated impedance matrix central unit calculate voltage at individual nodes (Vbus) using load flow analysis. 16 BASIC PRINCIPLE(Contd….) = Vbus  Periodically measured node voltage due to HF signal using smart meter is stored in central unit as Vmeas matrix.
  17. 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 17
  18. 18. FAULT DETECTION AND LOCALIZING (Contd…) 18 Graph showing fault near to node 34
  19. 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 19