Method and arrangement for direct current circuit interruption

Abstract

In the direct current circuit interruption arrangements disclosed in the specification, a solid state circuit interrupter interrupts the connection in a circuit path between a power source and a load. The stored energy in the circuit is dissipated in a resistive commutation circuit by using controllable power semiconductors such as Insulated Gate Bipolar Transistors to increase resistance between the terminals of the circuit interruption arrangement. An in-line power semiconductor switch acts as the circuit disconnecting device and is shunted by a resistive commutation circuit consisting of a plurality of solid state commutation switches and resistors in various configurations which act to dissipate the energy. In one embodiment the solid state switches in the commutation circuit are connected to a common circuit interrupter terminal and to a resistor through a series of taps on the resistor and the resistor is connected to the other circuit interrupter terminal. In another embodiment, the commutation circuit consists of parallel branches each having a solid state switch in series with a resistor and each branch is shunted across the circuit interrupter. In a further embodiment, the circuit path between the power source and the load consists of a plurality of parallel cables and each cable has an in-line solid state switch with a shunted resistive commutation circuit. In each of the embodiments the in-line solid state switches are opened and the solid state commutation switches are closed simultaneously, introducing resistance into the circuit path. The commutation switches are then sequentially opened to further increase the circuit resistance and complete the circuit interruption without causing electric potentials to exceed the device ratings for the circuit interrupter.