Ground fault current measuring device and ground fault current measuring method

摘要

PROBLEM TO BE SOLVED: To accurately measure ground fault current flowing through a three-phase AC main circuit.SOLUTION: A ground fault current measuring device 1 comprises an addition unit 13. Ground fault current flowing through each of a secondary and tertiary of a current transformer with a tertiary winding connected with a main circuit is measured by an ampere meter 6, received via a communication unit 11 of the ground fault current measuring device 1 and stored in a database 14 every sampling time. The addition unit 13 refers to the database 14, adds current values at the secondary and tertiary of the current transformer with a tertiary winding for each phase, and stores the added current value for each phase in the database 14. Thus, the ground fault current in the main circuit is calculated.SELECTED DRAWING: Figure 2