Some Novel Techniques for Insulation Parameters Measurement and Petersen-Coil Control in Distribution Systems

The traditional resonance grounding method is hard to completely satisfy the requirement of suppressing normal neutral-to-ground voltage and self-extinguishing grounding fault arcs in asymmetry distribution systems. For improvement, a new grounding method of a Petersen-coil in parallel with a reactor is developed, and some novel techniques for insulation parameters measurement and Petersen-coil control are proposed in this paper. An interpolation algorithm is presented to calculate the distribution systems resonance frequency. The insulation parameters (including capacitance to earth, leakage conductance, damping coefficient, and dissipation factor) are measured by the injecting resonance signal. The measured insulation parameters are then applied in Petersen-coil tuning. The new grounding equipment and the device for insulation parameters measurement and Petersen-coil control are developed. The results of laboratory tests and distribution systems operation show that the novel Petersen-coil control techniques can satisfy the requirement of asymmetry distribution systems. The proposed measurement method of insulation parameters is simple, convenient, precise, and tested in real time without power supply interrupting.