The use of phase voltage modules to select the damaged phase in case of single-phase earth faults

Abstract

In case of short circuits, the selection of damaged phases always precedes the determination of the damage location. To select the damaged phase, filter selector of the damaged phase are widely used, using symmetrical components of phase currents. In networks with an isolated neutral, the phase currents during a ground fault are determined mainly by load currents and in most cases the phase current of the damaged phase differs little from the currents in the undamaged phases. Therefore, phase currents and their symmetrical components are not used to select the damaged phase in single-phase short circuits. To select the damaged phase in networks with an isolated neutral, the properties of the phase voltage modules and the neutral offset voltage are used. Single-phase earth faults occur, as a rule, through fault resistances, the values of which can reach several thousand ohms. Therefore, the study of devices for selecting the damaged phase using voltage modules with single-phase earth faults through significant fault resistances is an urgent task. The purpose of the article is to investigate the properties and consider the directions of improvement of damaged phase sensors using phase voltage modules, to determine the areas of their selective action depending on the magnitude of the fault resistance at the point of damage. Describe algorithms in which the voter will act selectively both with metal damages and with damages through fault resistance.

Keywords

• single-phase earth faults
• device for selecting the damaged phase
• fault resistance