全功率型逆变电源侧工频变化量距离保护性能下降机理分析  

Performance degradation mechanism analysis of power frequency variation distance protection on full power inverter power supply side

作　　者：高靖怡 翁汉琍[1] 林湘宁[2] 吴宇奇 康涛 GAO Jingyi;WENG Hanli;LIN Xiangning;WU Yuqi;KANG Tao(Hubei Provincial Collaborative Innovation Center for New Energy Microgrid,Three Gorges University,Yichang 443002,China;State Key Laboratory of Strong Electromagnetic Engineering and New Technology,Huazhong University of Science and Technology,Wuhan 430074,China)

机构地区：[1]三峡大学新能源微电网湖北省协同创新中心,湖北宜昌443002 [2]华中科技大学强电磁工程与新技术国家重点实验室,湖北武汉430074

出　　处：《电力自动化设备》2024年第10期157-164,共8页Electric Power Automation Equipment

基　　金：国家自然科学基金资助项目(52077120)。

摘　　要：受逆变型分布式电源(IIDG)系统内阻抗不稳定的影响,工频变化量距离保护在全功率型逆变电源侧存在拒动风险,但现有理论未能从机理方面明确指出造成内阻抗不稳定的具体因素,难以提出针对性的保护改进方案。为了深入探究IIDG侧工频变化量距离保护性能急剧下降的机理,基于阻抗平面法分析指出,在全功率型逆变电源控制策略的作用下,IIDG侧正序电流增量表现为相位、幅值受控的独立变量,其与过渡电阻共同构成的附加阻抗大小随故障工况变化且矢量方向发生不确定性偏转,导致保护正确动作可行域不明晰,在传统阻抗继电器整定判据下保护可靠性严重劣化。在此基础上,进一步研究了主流的PQ控制及低电压穿越控制策略对该保护动作安全性和耐受过渡电阻能力的影响。基于PSCAD/EMTDC的仿真结果验证了理论分析的正确性,为工频变化量距离保护在IIDG并网工况下故障响应能力的恢复提供了有益的理论参考。Due to the instability of internal impedance in the inverter interface distributed generation(IIDG)system,there is a risk of rejection of power frequency variation distance protection on the full power inverter power supply side.However,the existing theories have failed to state the specific factors that cause inter⁃nal impedance instability from a mechanistic perspective,making it difficult to propose targeted protection improvement schemes.In order to deeply explore the mechanism of the sharp performance degradation of power frequency variation distance protection on IIDG side,based on impedance plane method analysis,it is pointed out that under the control strategy of the full power inverter power supply,the positive-sequence current increment on the IIDG side is an independent variable with controlled phase and amplitude,and the additional impedance formed by it and the transition resistance changes with the fault condition and the vector direction undergoes uncertain deflection,which leads to unclear feasible range for correct opera⁃tion of the protection,and serious degradation of protection reliability under traditional impedance relay set⁃ting criteria.On this basis,further research is conducted on the impact of mainstream PQ control and low voltage ride through control strategies on the safety of the protection action and the ability to withstand transition resistance.The simulative results based on PSCAD/EMTDC verify the correctness of the theore-tical analysis,providing a useful theoretical reference for the recovery of fault response ability of power fre⁃quency variation distance protection under IIDG grid connection conditions.

关 键 词：工频变化量距离保护 继电保护 逆变型分布式电源 阻抗平面法 过渡电阻 

分 类 号：TM77[电气工程—电力系统及自动化]