Dynamics performance of automatic mechanically switched capacitors on transmission systems near voltage collapse

Many transmission systems today are heavily loaded making them more vulnerable to voltage collapse. Substantial amounts of capacitive compensation can be required to maintain acceptable voltage levels following critical circuit trips. Because System conditions vary compensation cannot be permanently connected but controlled accordingly. Static var compensators (SVQ or mechanically switched capacitors (MSC) can be used to support system voltages, the latter which are less expensive but whose automatic control may pose difficulties. Long term dynamic studies have identified that hunting can occur between MSC and on load tap-changers under criticai conditions.