The solid state fault interruption device (SSFID) is used for the purpose of quickly isolating sections of power networks under permanent faults. The SSFID is tested for performance by simulation in a simulated medium voltage system. A comparison with the conventional breaker is presented in response to system faults in the presence of wind power plants and other distributed energy resources. The SSFID appears to be a superior alternative to the contemporary mechanical circuit breaker in isolating faulted sections. However, some high transients may appear on the network because of the operation of the device.