Multifunction hybrid solid-state switchgear

A hybrid solid-state switchgear for accommodating power transmission or distribution, circuit breaking or fault current limiting in a power transmission or distribution system, and for carrying an electric current through the switchgear, wherein the power transmission or distribution system is electrically connected to a source bus, the source bus being connected to a power source through the hybrid solid-state switchgear comprising:

• a mechanical switch and a solid-state switch adapted to be connected to a voltage source, wherein the solid-state switch is connected in parallel with the mechanical switch;
• a means for receiving information for monitoring for a fault current condition across the mechanical switch and the solid-state switch;
• wherein the solid-state switch includes a diode bridge having a bidirectional switch disposed therein;
• wherein the bidirectional switch is capable of protecting against the fault current condition;
• and,
• wherein when the switchgear is operating during a fault current condition, fault current magnitude is controlled by pulse width modulation switching, the switchgear further comprising a snubber circuit to regulate the fault current magnitude, a transient-voltage suppressor to allow a gate triggered over-voltage condition, and a varistor to absorb transient over-voltage.

A hybrid solid-state switchgear for accommodating power transmission or distribution, circuit breaking or fault current limiting in a power transmission or distribution system, and for carrying an electric current through the switchgear, wherein the power transmission or distribution system is electrically connected to a source bus, the source bus being connected to a power source through the hybrid solid-state switchgear comprising:

• a mechanical switch and a solid-state switch adapted to be connected to a voltage source, wherein the solid-state switch is connected in parallel with the mechanical switch;
• a means for receiving information for monitoring for a fault current condition across the mechanical switch and the solid-state switch;
• wherein the solid-state switch includes a diode bridge having a bidirectional switch disposed therein;
• wherein the bidirectional switch is capable of protecting against the fault current condition;
• and,
• wherein when a fault condition is detected, the mechanical switch can stop operation and the solid-state switch can begin operation, and wherein the means for receiving monitoring information comprises a current sensor for monitoring a fault current condition being coupled with a pulse width modulator control;
• further comprising:
• a first voltage sensor coupled with the pulse width modulator control for maintaining a constant voltage level;
• a second voltage sensor for monitoring the voltage across a gate of a gate-turn-off thyristor;
• a temperature sensor coupled with the solid-state switch for monitoring operating temperatures of the solid-state switch;
• the pulse width modulator controlling the gate-turn-off thyristor, the pulse width modulator controlled gate-turn-off thyristor being connected to the first voltage sensor, the second voltage sensor, the current sensor and the temperature sensor;
• and,
• a varistor connected in parallel with the gate-turn-off thyristor capable of absorbing transient over-voltage,
• wherein the gate-turn-off thyristor is adapted to reduce gate drive voltage across the solid-state switch, inducing the hybrid solid-state switchgear into high impedance mode.