Fault direction determination

Abstract

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 (phiPF) of this voltage (VPF) before a fault is stored, the phase (phiF) of this voltage (VF) at the end of a time interval (TI) following directly after a detected fault is determined, a phase offset (phiO) is determined as the difference between the phase (phiPF) of the measured voltage (VPF) before the fault and the phase (phiF) of the measured voltage (VF) at the end of the time interval (TI) and the phase (phiF) of the measured voltage (VF) after the detection of the fault is adjusted with the phase offset (phiO).Thereafter the adjusted measured voltage is used in determining the direction of fault in relation to the measurement node.

Description

Determining the direction of failure technical field The invention relates to the field of power systems. More particularly, the present invention relates to a method and computer program product for determining the direction of a fault in an electrical power system and a fault handling device providing such fault direction determination. Background technique In the field of power systems, it is important to detect and locate faults safely to be able to carry out necessary measures, such as disconnecting parts of the system, similar to disconnecting power lines. Fault handling devices used for this purpose are often called protective relays. Such devices are usually connected to a measurement node of the power system, which may be provided in the power line. When a fault is detected, it is then necessary to determine the direction of the fault with respect to the node. Traditionally, voltages have been measured and stored prior to failure. Then, when a fault is detect...

AI Technical Summary

Problems solved by technology

A problem with this approach is that the reference voltage is unreliable if for example the power system is set in motion that starts to oscillate or changes frequency

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