Patent attributes
The invention concerns a method and computer program product for determining the direction of fault in an electrical power system as well as to a fault handling device. In the fault handling device the voltage at a measurement node of the power system is measured, the phase (φPF) of this voltage (VPF) before a fault is stored, the phase (φF) of this voltage (VF) at the end of a time interval (TI) following directly after a detected fault is determined, a phase offset (φO) is determined as the difference between the phase (φPF) of the measured voltage (VPF) before the fault and the phase (φF) of the measured voltage (VF) at the end of the time interval (TI) and the phase (φF) of the measured voltage (VF) after the detection of the fault is adjusted with the phase offset (φO). Thereafter the adjusted measured voltage is used in determining the direction of fault in relation to the measurement node.
