MODULAR THYRISTOR CONTROLLED SERIES CAPACITOR CONTROL SYSTEM

摘要

A modular thyristor controlled series capacitor (TCSC) system (202), including a method and apparatus, uses phase controlled firing based on monitored capacitor voltage Vc and line current I1. For vernier operation, the TCSC system predicts an upcoming firing angle for switching a thyristor (35) controlled commutating circuit to bypass line current around a series capacitor C. Each bypass current pulse changes the capacitor voltage Vc proportionally to the integrated value of the current command from a higher-level controller (86) to control bypass thyristor duty to minimize thyristor damage, and to prevent capacitor voltage drift during line current disturbances. In a multi-module TCSC system, the higher level controller accommodates competing objectives of various system demands, including minimizing losses in scheduling control (230), stabilizing transients (236), damping subsynchronous resonance (SSR) oscillations (234), damping direct current (DC) offset, and damping power-swings (232).