filter design for electrified railways DIgSILENT USER GROUP Sydney 5 September 2013 M Jansen, S Hagaman, T George
Railway electrification project Adds significant unbalanced non-linear load to the grid PowerFactory used for emission/compliance /rating EMT review Protection design
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
Emission limits Emission limit (% of V1) 1.5 1.0 0.5 0 THD 7 13 19 25 31 37 43 49 order
Range of network conditions Network impedance (Ω) 1000 100 10 0 5 10 15 20 25 30 35 40 45 50 Frequency ( 50 Hz)
Current spectra Current emission (% of V1) 10 1 0.1 0.01 Measured Expanded Used 0.001 THD 7 13 19 25 31 37 43 49 order
Voltage distortion without filters PoC voltage distortion (% of V1) 10 1 0.1 0.01 0.001 THD 7 13 19 25 31 37 43 49 order
Filter configuration From 50 kv switchroom Phase A Shunt Third Fifth Ninth Phase B
Voltage distortion with filters PoC voltage distortion (% of V1) 1 0.1 0.01 0.001 THD 7 13 19 25 31 37 43 49 order
Filter parameters Rating C L R p Tuned to Branch Type (Mvar) (µf) (mh) (Ω) (Hz) Shunt 20 398 Third Single tuned 7 7.92 142 150 Fifth Damped 5 6.11 66.3 800 250 Ninth Damped 18 22.6 5.53 50 450
Component ratings Capacitor V N Reactor I RMS Resistor P R (kv) (A) (kw) Third 78.2 178.78 Fifth 64.8 117.21 16 Ninth 61.0 414.45 80
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
Model augmentation for TNSP Network T1 132 kv T2 50 kv RL1 RL3 HF1 RL4 RL5 HF2 Stray capacitance Surge arrester RL2 RL6
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
Switching study Capacitor voltage (kv) 200 0 V C3 V C5 V C9 0.02 0.04 0.06 0.08 0.10 Time (s) Branch current (ka) 1 0 1 I 3 I 5 I 9 0.02 0.04 0.06 0.08 0.10 Time (s)
Mitigation measures Switching transient Surge arresters specified across the 3 rd tuned branch capacitor bank (approaching IEC 60871-1 peak limit) Overcurrent protection graded to avoid spurious trips on filter energisation Lightning surge Surge arresters specified for the filter busbars
Capacitor bank voltages with surge arresters 200 175.4 kv VC3 (kv) 0 200 IEC 60871 voltage withstand limit -205.9 kv 0.005 0.010 0.015 0.020 Time (s)
Surge arrester current PoW switching IMOV (ka) 0 0.2 0.4 PoW time 6 ms, I peak = -380 A 0.005 0.010 0.015 0.020 0.025 0.030 Time (s)
Surge arrester current Lightning Current (ka) 10 0 0.1 0 0.1 0.2 Time (ms) Energy (kj) 20 0 0.1 0 0.1 0.2 Time (ms)
Thank you for your time Questions?