Protection circuit for electrical power distribution system components

A transformer protection circuit electrically connected between a neutral connection of a power grid transformer and a ground, the transformer protection circuit comprising:

• a switch assembly electrically connected between the neutral connection of the power grid transformer and the ground, the switch assembly movable between an open position and a closed position, the switch assembly being configured to break alternating current (AC) and direct current (DC) from passing therethrough between the neutral connection and the ground;
• a direct current blocking component electrically connected in parallel with the switch assembly between the neutral connection and the ground;
• an overvoltage protection device electrically connected in parallel with the switch assembly and the direct current blocking component;
• and
• a direct current sensor device positioned to detect direct current across the overvoltage protection device.

A method of operating a transformer protection circuit comprising:

• detecting existence of an electrical event at a transformer neutral of a power grid transformer capable of causing damage to the power grid transformer;
• in response to detecting the existence of the electrical event, sending an electrical signal to actuate a switch assembly from a closed position to an open position, the switch assembly being electrically connected between the transformer neutral and a ground, thereby electrically disconnecting a conductive path between the transformer neutral and the ground;
• while the switch assembly is open, detecting a current indicating an overvoltage event causing electrical discharge across an overvoltage protection device that is electrically connected in parallel with the switch assembly;
• and
• in response to detecting the overvoltage event, actuating the switch assembly from the open position to the closed position and back to the open position.