Patent ID: 11959975
Assignee: BENDER GMBH & CO. KG
Field: Measurement (Instruments)
Classification: CPC G | IPC G

Claim 1:
2. A method for selectively determining a partial system leakage capacitance Cx of an outgoing line (4) in a branched ungrounded power supply system (2) which is monitored using an insulation monitoring device (10) which actively superposes a measuring alternating voltage Um on the ungrounded power supply system (2), the method comprising the following steps:
detecting a partial insulation resistance Rx of the outgoing line (4), calculating partial system leakage capacitance Cx according to Cx=ic(t)/(due(t)/dt),
with a leakage current ic(t) flowing via partial system leakage capacitance Cx and a temporal sequence of measured non-stationary conductor-to-ground voltage ue(t) which drops via the outgoing line (4) and whose temporal derivative is due(t)/dt, leakage current ic(t) being calculated from ic(t)=ix(t)−ue(t)/Rx with a temporal sequence of non-stationary partial current ix(t) measured in the outgoing line (4) and detected partial insulation resistance Rx, meaning partial system leakage capacitance Cx is calculated from Cx=(ix(t)−(ue(t)/Rx))/(due(t)/dt).