Modelling the system dynamics of islanding asynchronous generators / Telemark University
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The document discusses the modeling of system dynamics for islanding asynchronous generators at Telemark University College, detailing a specific event where an earth circuit fault caused a disconnection in the Lønnestad radial, leading to significant power imbalances and voltage issues. Simulation results show that asynchronous generators can operate independently when sufficient capacitance is available, resulting in rapid voltage buildup. The findings emphasize the importance of correct parameterization of protection relays to prevent adverse effects during such events.
Modelling the system dynamics of islanding asynchronous generators / Telemark University
- 1. Telemark University College Norway Modelling the system dynamics of islanding asynchronous generators 10th International Modelica Conference 2014 Håkon Molland Edvardsen Dietmar Winkler Telemark University College Norway 12th March 2014
- 2. I. Introduction What is it about? What is it about? Edvardsen & Winkler (TUC) Modelica’2014 12th March 2014 2 / 18
- 3. I. Introduction What is it about? What is it about? Figure : Broken surge arrester Edvardsen & Winkler (TUC) Modelica’2014 12th March 2014 2 / 18
- 4. I. Introduction What is it about? What is it about? Figure : Broken surge arrester Figure : End-termination of supply cable Edvardsen & Winkler (TUC) Modelica’2014 12th March 2014 2 / 18
- 5. II. Practical Background Location Location Where in Europe? Edvardsen & Winkler (TUC) Modelica’2014 12th March 2014 3 / 18
- 6. II. Practical Background Location Location Locally Edvardsen & Winkler (TUC) Modelica’2014 12th March 2014 4 / 18
- 7. II. Practical Background The power stations The power stations Grunnå and Sagbekken 1 and Sagbekken 2&3 Edvardsen & Winkler (TUC) Modelica’2014 12th March 2014 5 / 18
- 8. II. Practical Background The power stations The power stations Grunnå and Sagbekken 1 and Sagbekken 2&3 Figure : Grunnåi (Synch - 15MW) Edvardsen & Winkler (TUC) Modelica’2014 12th March 2014 5 / 18
- 9. II. Practical Background The power stations The power stations Grunnå and Sagbekken 1 and Sagbekken 2&3 Figure : Grunnåi (Synch - 15MW) Figure : Sagbekken 2&3 (Asynch 75+75 & 75+250 kW) Edvardsen & Winkler (TUC) Modelica’2014 12th March 2014 5 / 18
- 10. II. Practical Background The power stations The power stations Reinstul - 18kW (traditional Norwegian power station) Edvardsen & Winkler (TUC) Modelica’2014 12th March 2014 6 / 18
- 11. II. Practical Background The power stations The power stations Reinstul - 18kW (traditional Norwegian power station) Edvardsen & Winkler (TUC) Modelica’2014 12th March 2014 6 / 18
- 12. II. Practical Background The power stations The power stations Total capacity Grunnåi: 15MW - synchronous Sagbekken 1: 2x100kW & 200kW - asynchronous Sagbekken 2: 75kW & 250kW - asynchronous Sagbekken 3: 75kW & 75kW - asynchronous Total: 15.85MW Edvardsen & Winkler (TUC) Modelica’2014 12th March 2014 7 / 18
- 13. II. Practical Background What happend? What happend? Possible sequence Edvardsen & Winkler (TUC) Modelica’2014 12th March 2014 8 / 18
- 14. II. Practical Background Reconstruction of events Reconstruction of events Difficult... 1 Earth circuit fault in Grunnåi (Terminator) 2 The protection relay disconnected the Lønnestad radial 3 Result: heavy imbalance of active power and reactive power in the now islanded radial. 4 Rapid frequency increase since Grunnåi did not correct for the overproduction 5 The generator circuit breaker disconnected Grunnåi from the grid, due to triggering of the over-frequency relay (51Hz and 0.1 seconds). 6 Asynchronous generators in Sagbekken 1, 2 & 3 alone in the island. 7 Sufficient amount of reactive power in the grid to initiate self-excitation. 8 Successive voltage build-up, which resulted in significant over-voltages in the grid. 9 Surge arresters to breakdown. 10 Arcing ⇒ low impedance in the grid ⇒ stops self-excitation Edvardsen & Winkler (TUC) Modelica’2014 12th March 2014 9 / 18
- 15. II. Practical Background Reconstruction of events Reconstruction of events Difficult... 1 Earth circuit fault in Grunnåi (Terminator) 2 The protection relay disconnected the Lønnestad radial 3 Result: heavy imbalance of active power and reactive power in the now islanded radial. 4 Rapid frequency increase since Grunnåi did not correct for the overproduction 5 The generator circuit breaker disconnected Grunnåi from the grid, due to triggering of the over-frequency relay (51Hz and 0.1 seconds). 6 Asynchronous generators in Sagbekken 1, 2 & 3 alone in the island. 7 Sufficient amount of reactive power in the grid to initiate self-excitation. 8 Successive voltage build-up, which resulted in significant over-voltages in the grid. 9 Surge arresters to breakdown. 10 Arcing ⇒ low impedance in the grid ⇒ stops self-excitation Edvardsen & Winkler (TUC) Modelica’2014 12th March 2014 9 / 18
- 16. II. Practical Background Reconstruction of events Reconstruction of events Difficult... 1 Earth circuit fault in Grunnåi (Terminator) 2 The protection relay disconnected the Lønnestad radial 3 Result: heavy imbalance of active power and reactive power in the now islanded radial. 4 Rapid frequency increase since Grunnåi did not correct for the overproduction 5 The generator circuit breaker disconnected Grunnåi from the grid, due to triggering of the over-frequency relay (51Hz and 0.1 seconds). 6 Asynchronous generators in Sagbekken 1, 2 & 3 alone in the island. 7 Sufficient amount of reactive power in the grid to initiate self-excitation. 8 Successive voltage build-up, which resulted in significant over-voltages in the grid. 9 Surge arresters to breakdown. 10 Arcing ⇒ low impedance in the grid ⇒ stops self-excitation Edvardsen & Winkler (TUC) Modelica’2014 12th March 2014 9 / 18
- 17. II. Practical Background Reconstruction of events Reconstruction of events Difficult... 1 Earth circuit fault in Grunnåi (Terminator) 2 The protection relay disconnected the Lønnestad radial 3 Result: heavy imbalance of active power and reactive power in the now islanded radial. 4 Rapid frequency increase since Grunnåi did not correct for the overproduction 5 The generator circuit breaker disconnected Grunnåi from the grid, due to triggering of the over-frequency relay (51Hz and 0.1 seconds). 6 Asynchronous generators in Sagbekken 1, 2 & 3 alone in the island. 7 Sufficient amount of reactive power in the grid to initiate self-excitation. 8 Successive voltage build-up, which resulted in significant over-voltages in the grid. 9 Surge arresters to breakdown. 10 Arcing ⇒ low impedance in the grid ⇒ stops self-excitation Edvardsen & Winkler (TUC) Modelica’2014 12th March 2014 9 / 18
- 18. II. Practical Background Reconstruction of events Reconstruction of events Difficult... 1 Earth circuit fault in Grunnåi (Terminator) 2 The protection relay disconnected the Lønnestad radial 3 Result: heavy imbalance of active power and reactive power in the now islanded radial. 4 Rapid frequency increase since Grunnåi did not correct for the overproduction 5 The generator circuit breaker disconnected Grunnåi from the grid, due to triggering of the over-frequency relay (51Hz and 0.1 seconds). 6 Asynchronous generators in Sagbekken 1, 2 & 3 alone in the island. 7 Sufficient amount of reactive power in the grid to initiate self-excitation. 8 Successive voltage build-up, which resulted in significant over-voltages in the grid. 9 Surge arresters to breakdown. 10 Arcing ⇒ low impedance in the grid ⇒ stops self-excitation Edvardsen & Winkler (TUC) Modelica’2014 12th March 2014 9 / 18
- 19. II. Practical Background Reconstruction of events Reconstruction of events Difficult... 1 Earth circuit fault in Grunnåi (Terminator) 2 The protection relay disconnected the Lønnestad radial 3 Result: heavy imbalance of active power and reactive power in the now islanded radial. 4 Rapid frequency increase since Grunnåi did not correct for the overproduction 5 The generator circuit breaker disconnected Grunnåi from the grid, due to triggering of the over-frequency relay (51Hz and 0.1 seconds). 6 Asynchronous generators in Sagbekken 1, 2 & 3 alone in the island. 7 Sufficient amount of reactive power in the grid to initiate self-excitation. 8 Successive voltage build-up, which resulted in significant over-voltages in the grid. 9 Surge arresters to breakdown. 10 Arcing ⇒ low impedance in the grid ⇒ stops self-excitation Edvardsen & Winkler (TUC) Modelica’2014 12th March 2014 9 / 18
- 20. II. Practical Background Reconstruction of events Reconstruction of events Difficult... 1 Earth circuit fault in Grunnåi (Terminator) 2 The protection relay disconnected the Lønnestad radial 3 Result: heavy imbalance of active power and reactive power in the now islanded radial. 4 Rapid frequency increase since Grunnåi did not correct for the overproduction 5 The generator circuit breaker disconnected Grunnåi from the grid, due to triggering of the over-frequency relay (51Hz and 0.1 seconds). 6 Asynchronous generators in Sagbekken 1, 2 & 3 alone in the island. 7 Sufficient amount of reactive power in the grid to initiate self-excitation. 8 Successive voltage build-up, which resulted in significant over-voltages in the grid. 9 Surge arresters to breakdown. 10 Arcing ⇒ low impedance in the grid ⇒ stops self-excitation Edvardsen & Winkler (TUC) Modelica’2014 12th March 2014 9 / 18
- 21. II. Practical Background Reconstruction of events Reconstruction of events Difficult... 1 Earth circuit fault in Grunnåi (Terminator) 2 The protection relay disconnected the Lønnestad radial 3 Result: heavy imbalance of active power and reactive power in the now islanded radial. 4 Rapid frequency increase since Grunnåi did not correct for the overproduction 5 The generator circuit breaker disconnected Grunnåi from the grid, due to triggering of the over-frequency relay (51Hz and 0.1 seconds). 6 Asynchronous generators in Sagbekken 1, 2 & 3 alone in the island. 7 Sufficient amount of reactive power in the grid to initiate self-excitation. 8 Successive voltage build-up, which resulted in significant over-voltages in the grid. 9 Surge arresters to breakdown. 10 Arcing ⇒ low impedance in the grid ⇒ stops self-excitation Edvardsen & Winkler (TUC) Modelica’2014 12th March 2014 9 / 18
- 22. II. Practical Background Reconstruction of events Reconstruction of events Difficult... 1 Earth circuit fault in Grunnåi (Terminator) 2 The protection relay disconnected the Lønnestad radial 3 Result: heavy imbalance of active power and reactive power in the now islanded radial. 4 Rapid frequency increase since Grunnåi did not correct for the overproduction 5 The generator circuit breaker disconnected Grunnåi from the grid, due to triggering of the over-frequency relay (51Hz and 0.1 seconds). 6 Asynchronous generators in Sagbekken 1, 2 & 3 alone in the island. 7 Sufficient amount of reactive power in the grid to initiate self-excitation. 8 Successive voltage build-up, which resulted in significant over-voltages in the grid. 9 Surge arresters to breakdown. 10 Arcing ⇒ low impedance in the grid ⇒ stops self-excitation Edvardsen & Winkler (TUC) Modelica’2014 12th March 2014 9 / 18
- 23. II. Practical Background Reconstruction of events Reconstruction of events Difficult... 1 Earth circuit fault in Grunnåi (Terminator) 2 The protection relay disconnected the Lønnestad radial 3 Result: heavy imbalance of active power and reactive power in the now islanded radial. 4 Rapid frequency increase since Grunnåi did not correct for the overproduction 5 The generator circuit breaker disconnected Grunnåi from the grid, due to triggering of the over-frequency relay (51Hz and 0.1 seconds). 6 Asynchronous generators in Sagbekken 1, 2 & 3 alone in the island. 7 Sufficient amount of reactive power in the grid to initiate self-excitation. 8 Successive voltage build-up, which resulted in significant over-voltages in the grid. 9 Surge arresters to breakdown. 10 Arcing ⇒ low impedance in the grid ⇒ stops self-excitation Edvardsen & Winkler (TUC) Modelica’2014 12th March 2014 9 / 18
- 24. IV. Modelling The Lønnestad radial The Lønnestad radial Using Electric Power Library Edvardsen & Winkler (TUC) Modelica’2014 12th March 2014 10 / 18
- 25. IV. Modelling The self-excitation The self-excitation Model of one asynchronous generator Edvardsen & Winkler (TUC) Modelica’2014 12th March 2014 11 / 18
- 26. IV. Modelling The self-excitation The self-excitation Simulation results, no capacitance, disconnection at t = 1s Edvardsen & Winkler (TUC) Modelica’2014 12th March 2014 12 / 18
- 27. IV. Modelling The self-excitation The self-excitation Simulation results, influence of reactive and active load, disconnection at t = 1s Edvardsen & Winkler (TUC) Modelica’2014 12th March 2014 13 / 18
- 28. IV. Modelling The self-excitation The self-excitation Simulation results, influence of reactive and active load, disconnection at t = 1s Edvardsen & Winkler (TUC) Modelica’2014 12th March 2014 13 / 18
- 29. IV. Modelling Ground fault Ground fault Sub-model Sagbekken 1 Edvardsen & Winkler (TUC) Modelica’2014 12th March 2014 14 / 18
- 30. IV. Modelling Ground fault Ground fault Model of Lønnestad radial with phase to ground fault Edvardsen & Winkler (TUC) Modelica’2014 12th March 2014 15 / 18
- 31. IV. Modelling Ground fault Ground fault Simulation results Edvardsen & Winkler (TUC) Modelica’2014 12th March 2014 16 / 18
- 32. IV. Modelling Ground fault Ground fault Simulation results Took 1.5 seconds from ground fault until total disconnect Maximum voltage reached: 53.36kV Phase C over 30kV for 0.7 seconds Edvardsen & Winkler (TUC) Modelica’2014 12th March 2014 16 / 18
- 33. Conclusions Conclusions Asynchronous generators can operate stand-alone when enough capacitance available Edvardsen & Winkler (TUC) Modelica’2014 12th March 2014 17 / 18
- 34. Conclusions Conclusions Asynchronous generators can operate stand-alone when enough capacitance available Capacitance can come from long supply lines Edvardsen & Winkler (TUC) Modelica’2014 12th March 2014 17 / 18
- 35. Conclusions Conclusions Asynchronous generators can operate stand-alone when enough capacitance available Capacitance can come from long supply lines Self-excitation leads to fast voltage build-ups Edvardsen & Winkler (TUC) Modelica’2014 12th March 2014 17 / 18
- 36. Conclusions Conclusions Asynchronous generators can operate stand-alone when enough capacitance available Capacitance can come from long supply lines Self-excitation leads to fast voltage build-ups Simulations showed possible voltage build-up of 50kV within 0.4s! Edvardsen & Winkler (TUC) Modelica’2014 12th March 2014 17 / 18
- 37. Conclusions Conclusions Asynchronous generators can operate stand-alone when enough capacitance available Capacitance can come from long supply lines Self-excitation leads to fast voltage build-ups Simulations showed possible voltage build-up of 50kV within 0.4s! Correct parameterisation of protection relays crucial Edvardsen & Winkler (TUC) Modelica’2014 12th March 2014 17 / 18
- 38. Conclusions Conclusions Asynchronous generators can operate stand-alone when enough capacitance available Capacitance can come from long supply lines Self-excitation leads to fast voltage build-ups Simulations showed possible voltage build-up of 50kV within 0.4s! Correct parameterisation of protection relays crucial Need to take self-excitation effect into account Edvardsen & Winkler (TUC) Modelica’2014 12th March 2014 17 / 18
- 39. Telemark University College Norway Thank you for your attention! Questions? [email protected] Acknowlegdements: