Harmonic filter design for electrified railways

Transcription

1 filter design for electrified railways DIgSILENT USER GROUP Sydney 5 September 2013 M Jansen, S Hagaman, T George

2 Railway electrification project Adds significant unbalanced non-linear load to the grid PowerFactory used for emission/compliance /rating EMT review Protection design

3 Feeder station topology TNSP Network (AB) (BC) 132 kv T1 T2 50 kv RL1 RL2 RL3 HF1 RL4 RL5 RL6 HF2 Note: (AB)/(BC) phasing is typical Requires single phase compensation Limited output power

4 Emission limits Emission limit (% of V1) THD order

5 Range of network conditions Network impedance (Ω) Frequency ( 50 Hz)

6 Current spectra Current emission (% of V1) Measured Expanded Used THD order

7 Voltage distortion without filters PoC voltage distortion (% of V1) THD order

8 Filter configuration From 50 kv switchroom Phase A Shunt Third Fifth Ninth Phase B

9 Voltage distortion with filters PoC voltage distortion (% of V1) THD order

10 Filter parameters Rating C L R p Tuned to Branch Type (Mvar) (µf) (mh) (Ω) (Hz) Shunt Third Single tuned Fifth Damped Ninth Damped

11 Component ratings Capacitor V N Reactor I RMS Resistor P R (kv) (A) (kw) Third Fifth Ninth

12 Electromagnetic study Design for electromagnetic transient (EMT) phenomena Peak voltage across capacitor banks Peak currents Protection setting stability Studies for switching transients and lightning surges Specification of mitigation measures

13 Model augmentation for TNSP Network T1 132 kv T2 50 kv RL1 RL3 HF1 RL4 RL5 HF2 Stray capacitance Surge arrester RL2 RL6

14 PowerFactory simulation Operational scenarios to define different switching arrangements 1 or 2 transformers online 1 or 2 filters online Several different track feeder arrangements Lightning strike points Study cases for each switching/lightning case Analysis of different point on wave switching DPL scripts to automate study cases, print plots and analyse waveforms

15 Switching study Capacitor voltage (kv) V C3 V C5 V C Time (s) Branch current (ka) I 3 I 5 I Time (s)

16 Mitigation measures Switching transient Surge arresters specified across the 3 rd tuned branch capacitor bank (approaching IEC peak limit) Overcurrent protection graded to avoid spurious trips on filter energisation Lightning surge Surge arresters specified for the filter busbars

17 Capacitor bank voltages with surge arresters kv VC3 (kv) IEC voltage withstand limit kv Time (s)

18 Surge arrester current PoW switching IMOV (ka) PoW time 6 ms, I peak = -380 A Time (s)

19 Surge arrester current Lightning Current (ka) Time (ms) Energy (kj) Time (ms)

20 Thank you for your time Questions?