Selective Isolation Continuous Monitoring System in the Networks of 6, 10kV

The need for the isolation selective monitoring for networks with the isolated neutral of 6, 10 kV is shown. The lack of monitoring systems possessing selectivity of action is presently noted. A possibility of isolation selective control on the basis of regime parameters measurement in networks of 6, 10 kV, such as voltage and currents at the beginning and the end of the line, and also angles between them is proved. According to the regime parameters measurement for the most difficult case, the line with tap, the analytical dependences for determination of isolation conductivity concerning the earth is given. Errors of the network conductivity determination concerning the earth in case of lines with tap in it are analyzed. It is shown that at isolation conductivity determination of a network concerning the earth by the formulas offered the error won’t exceed 10%. The increase of measurement accuracy can be provided with measurement of regime parameters at the beginning of the tap line.