Capacitor switching transient analysis on a transmission grid substation

Abstract

The quality of electric power system has a great concern and also it has been a constant topic of study. A transient originated from capacitor bank switching are main reason which affects the power quality. The analysis, simulation and optimal use of capacitor banks under harmonic conditions are required in a power network to optimally locate and sizing of a capacitor bank. The breaker switched capacitor (BSC) banks are commonly used for power factor correction, reactive power requirement and voltage support by many utilities in the world. Ceylon electricity board (CEB) has also installed total of 370 Mvar capacitor banks island-wide in transmission grid substations (GSS) in 33 kV level. The motivation for the study is the switched off capacitor banks at Thulhiriya GSS due to the failure of 100 Mvar BSC banks installed at the Pannipitiya GSS. Thulhiriya GSS was modelled as the case study to analyze the switching transients of the 33 kV BSC banks to the system. Data for the selected substation were recorded and analyzed and the selected substation was modelled using PSCAD simulation program to analyze the transients and harmonics. The results obtained for the Thulhiriya GSS are extrapolated to a general concept to suit any substation in the CEB network.