A SURGE SUPPRESSION NETWORK RESPONSIVE TO THE RATE OF CHANGE OF POWER DISTURBANCES

摘要

A surge suppression network for single and multiphase ac systems has a voltage clamping device connected in series with a gated crowbar device across the supply voltage in parallel with the load to be protected. A trigger circuit gates the crowbar device on in response to a specified rate of change of the supply voltage indicative of a surge. For higher levels of surge current shunting, pluralities of clamping devices and crowbar devices can be connected in parallel with a single trigger circuit simultaneously tinning on all of the crowbar devices for each phase. For crowbar devices such as TRIACs with different response characteristics to positive and negative surges and for unipolar devices such as SCRs, positive and negative subnetworks are connected in anti-parallel across the load.