Additional Low Frequency Signal Measurement Method of Insulation Resistance about Mine Cable

Considering the existing measurement method in mine's power system can not accurately distinguish ground insulation resistance and earth capacity, a new measurement method based on additional low frequency signal is proposed. The insulation resistance and earth capacity can be calculated by the new method based on additional low frequency signal. By MATLAB simulation technology, analysis result and the method of measuring insulation parameters are simulated. Simulation experiment shows that theoretical analysis results are correct. The method of additional low frequency power measuring insulation parameters can exactly measure insulation resistance and earth capacity. The measuring accuracy is good, the value of distributed capacitor has effect on measuring precision and the selection of signal frequency has direct effect on measuring precision. For the neutral point ungrounded system, this method can be realized by using the microcomputer and the insulation resistance can be measured easily on the online insulation monitoring system.