1.智能电网运行与控制湖南省重点实验室(长沙理工大学)，湖南省长沙市 410114;2.广东电网有限责任公司江门供电局，广东省江门市 529000
1.Hunan Province Key Laboratory of Smart Grids Operation and Control (Changsha University of Science and Technology), Changsha 410114, China;2.Jiangmen Power Supply Bureau of Guangdong Power Grid Co. Ltd., Jiangmen 529000, China.
This work is supported by National Natural Science Foundation of China (No. 51807012), Hunan Provincial Natural Science Foundation of China (No. 2019JJ50645) and Scientific Research Project of Hunan Province Education Department (No. 18K047).
In order to solve the measurement error problem of measuring insulation parameters to ground for resonance grounding distribution network caused by the leakage impedance of voltage transformer and damping resistance of branch for neutral point to ground, a novel dual-terminal resonance measurement method of insulation parameters to ground for resonance grounding distribution network is proposed. This method utilizes dual voltage transformer. A characteristic constant current signal with variable frequency is injected into distribution network through the internal voltage transformer of the arc-suppression coil or zero-sequence voltage transformer while the returned characteristic-frequency voltage signal is measured by another. After the equivalent transformation of zero-sequence resonant circuit with damping resistance, the system capacitance to ground and leakage conductance can be accurately calculated by correctly searching the resonant frequency of the system. Both the current injection and the voltage measuring unit of the proposed method directly act on the branch of insulation parameters to ground which eliminates the effect of the leakage impedance of voltage transformer and damping resistance and greatly improve the measurement accuracy of insulation parameters to ground. The proposed real-time measurement technology of insulation parameters to ground is simulated, analyzed and verified by field test in PSCAD/EMTDC simulation environment and 10 kV substation. The analysis results show that the proposed method has high measurement accuracy, whose parameters measuring process is safe, fast and easy to operate, and with no impact on the normal power supply of distribution network.
YU Kun,ZOU Hao,ZENG Xiangjun,et al.A Novel Double-terminal Resonance Measurement Method of Insulation Parameters to Ground for Resonance Grounding Distribution Network[J/OL].Automation of Electric Power Systems,http://doi.org/10.7500/AEPS20190523001.