Location Method of External Single-Phase Grounding Fault of Thermal Power Generating Unit

Abstract

The external transmission line of large thermal power unit has complex structure, many overhead lines and branch lines, and the load distribution along the line is uneven. When a single-phase grounding short circuit occurs, it is impossible to accurately locate and troubleshoot the fault in a short time. To solve this problem, this paper applies the line impedance fault location method to the single-phase grounding fault condition of the external transmission line of 220kV large thermal power unit, and uses the easily collected grounding current, grounding voltage and relevant line parameters to determine the fault location. In view of the fact that the actual measured data is easily affected by the transition resistance, the conjugate calculation method is used to eliminate the phase of the transition resistance, so as to make the fault location more accurate; Finally, the effectiveness and practicability of the proposed method are verified by Matlab / Simulink simulation.