Several ground faulted line detection methods based on zero-sequence current of fundamental wave were synthetically adopted to conquer the limitation of single method application.And all these methods were achieved with the same hardware structure.Amplitude and phase comparative methods of zero-sequence currents

zero-sequence current active components method and zero-sequence current increment method were analyzed.Then the hardware and software designs of the device were given.The experimental results and the field operating results show that the device operates steadily and detects faulted line accurately.