Current transformer protection device
AssigneeHydro-Quebec
InventorJulien Simard
Life of this patent
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Abstract
A protection system for protecting the secondary windings of current transformers against overvoltages. The protection system consists of a device shunting the secondary winding and having a triggering device operative when the winding is subjected to a voltage higher than the voltage appearing across the terminals of the secondary winding, under normal operating conditions and during a fault on the HV power network. The shunting device comprises a latching relay incorporating a coil which is energized by the triggering device to short-circuit the current secondary transformer through the relay contact, and, also, a voltage regulator connected in parallel with the relay coil. This protection system is simple, compact, lightweight and consumes no energy when the current transformer operates under normal conditions.
Claims5
A system for protecting the secondary winding of an HV current transformer of a power network against overvoltages caused by an open secondary circuit, said system comprising a shunting device of the mechanical latching type for short-circuiting said secondary winding, a triggering device acting as a crowbar and operative when subjected to a voltage higher than the voltage appearing across the terminals of said secondary winding in normal operating conditions and during a fault on the HV power network, said triggering device being connected in series with a voltage regulator acting as a clamp, and said shunting device being connected in parallel with said voltage regulator whereby said regulator will energize said shunting device to short-circuit said secondary winding of the current transformer.
Dependencies are inferred from the claim text.