Harmonic and Transient Overvoltage Analysis Concerning Capacitor Banks Switching in Yen Son Distribution Grid by using EMTP ☆

This paper presents the simulation results by using EMTP (Electromagnetic Transient Program) to estimate the effect of harmonic resonance and transient overvoltage due to capacitors switching in the 374E1.14 feeder, Yen Son distribution network, Tuyen Quang province. The simulation results showed that harmonic resonance occured at the capacitor banks location at Tan Binh substation since 11th harmonic current presented in this feeder and the capacitor size was 150kVAr. The harmonic voltage distortion factor THD obtained by the simulation was 6.48%. The capacitor sizes, in which harmonic resonance occurs, were then determined to avoid. Transient analysis showed that maximum overvoltage level due to capacitor banks switching achived 1.94pu. Simulation using 1Ω pre-insertion resistors proved that the reduction of the magnitudes of the transients in the voltage and current waveforms is possible.