On-Line Monitoring of Shunt Capacitor Bank Based on Relay Protection Device

Abstract

In modern power systems, the installation of a shunt capacitor bank is one of the cheapest and most widely used methods for improving the voltage profile. One shunt capacitor bank is composed of mass capacitor units and have ground, ungrounded, delta, wye connections that make configuration of capacitor banks is various. In the case of long-term operation, the failure of a single capacitor unit of a capacitor bank is likely to cause uneven voltage, which will lead to the breakdown and burning of the whole group, resulting in huge losses. The relay protection device can detect the simultaneous voltage and current of the capacitor. By utilizing these data from the relay, the abnormal state of the shunt capacitor banks at the initial stage of the fault can be found through monitoring the slight change in capacitance. Timely and early maintenance and repair would avoid capacitor bank faults and potentially greater economic losses. Capacitor banks have different connection modes. For ungrounded wye-connected capacitor banks with an unknown neutral point voltage, the capacitance parameters of each branch cannot be calculated. A parameter symmetry based on the calculation method for capacitor parameters is proposed. For long-term monitoring and observation of the capacitor capacitance value, the fault state and abnormal state of the capacitor are identified based on statistical methods. The simulation established by PSCAD verified that a relay protection device can realized an effective monitoring of the early abnormal state of the capacitor bank.

Application of Artificial Intelligence in Power System Monitoring and Fault Diagnosis

“…This section provides a summary of this Special Issue of Energies, covering published articles [1][2][3][4][5][6][7][8][9][10] which address several topics related to AI technologies in power system performance monitoring.…”

“…In [2], Lin et al proposed a new method for shunt capacitor monitoring. The method monitors the shunt capacitor bank via the synchronous voltage and branch current of the shunt capacitor bank, calculates the capacitance parameters of the ungrounded starconnected capacitor bank using the parameter symmetry of the capacitor parameter calculation method, and identifies the abnormal state of the capacitor according to the statistical method.…”