Brief description of the differential protection of an electrical connection of great length with capacitive current high in a network medium, high or very high voltage.

摘要

The method involves measuring capacitive current (I-capa) of an electrical link (10) during powering of the electrical link. Amplitude and phase of the measured capacitive current is stored in a memory when time is equal to 500 ms after starting the measurement. The measured capacitive current is subtracted from differential current to obtain corrected differential current. Phase of the measured capacitive current is controlled such the corrected differential current is adjusted close to zero. A differential protection relay is triggered during the event of defect on the electric link.