Abstract: A protective control apparatus and method is disclosed for protecting the operation of a power device upon detection of an internal fault condition. The power device has a circuit breaker for connecting the power device to a power supply. The protective control apparatus comprises a current measuring unit operatively connected to the power device for measuring currents within the power device and a protective relay processing unit connected to the current measuring unit for receiving the measured currents and connected to the circuit breaker for providing a control signal thereto. The protective relay processing unit performs a multi-resolution analysis of the measured currents preferably using Wavelet Packet Transform decomposition, to detect the internal fault condition, and upon detection of the internal fault condition, provides a control signal to disable the circuit breaker.