公开(公告)号：US11336084B1

公开(公告)日：2022-05-17

申请号：US17105945

申请日：2020-11-27

申请人： General Electric Company

发明人： Hessamoddin Jouybari Moghaddam ,  Ilia Voloh

IPC分类号： H02H7/16 ,  H02H3/40 ,  G01R31/40 ,  G01R31/64

摘要： A protection and monitoring system, device, and method for an electric power system, including a capacitor bank having multiple strings in each phase, voltage and current measuring devices, and relays to protect this capacitor bank. Each string can have multiple capacitor units and each unit can consist of multiple capacitor elements. The method may include: determining steady state operating condition using the obtained current and voltages, calculating and storing present time impedance value of each string into memory, calculating the string per unit impedance incremental quantity, detecting capacitor element failure based at least in part on this incremental quantity and calculating number of failed capacitor elements for each event, accumulating the number of failed capacitor elements, and performing a protection action when healthy capacitor elements are subject to an overvoltage limit. The method may be inherently immune or otherwise insensitive to capacitor variations due to aging, temperature change, instrument transformers errors, inaccuracy in data acquisition, and inherent manufacturing unbalance.