CAJ | 학술논문

针对交直流混联系统中直流保护在交流系统故障时误动的问题，基于某特高压直流系统的数字实时仿真系统(RTDS)，研究交流故障下直流系统的暂态响应特征。从交流故障与直流故障的相似性、直流保护原理和整定方法的不完善性两方面揭示了直流保护对交流故障的响应机理。基于直流保护对交流故障的响应机理，全面梳理出在原理上能反映交流故障的直流保护类型。结合某特高压直流系统的RT DS实验数据，详细分析了两侧交流系统故障时的低电压特征以及电流失衡特征所引发的直流保护误动情况。深入分析了交流故障下直流低电压保护、阀组差动保护以及桥差保护的误动机理，并提出相应的改进建议，为直流工程的更合理运行提供指导。
침대교직류혼련계통중직류보호재교류계통고장시오동적문제，기우모특고압직류계통적수자실시방진계통(RTDS)，연구교류고장하직류계통적잠태향응특정。종교류고장여직류고장적상사성、직류보호원리화정정방법적불완선성량방면게시료직류보호대교류고장적향응궤리。기우직류보호대교류고장적향응궤리，전면소리출재원리상능반영교류고장적직류보호류형。결합모특고압직류계통적RT DS실험수거，상세분석료량측교류계통고장시적저전압특정이급전류실형특정소인발적직류보호오동정황。심입분석료교류고장하직류저전압보호、벌조차동보호이급교차보호적오동궤리，병제출상응적개진건의，위직류공정적경합리운행제공지도。
To solve the malfunction of protection of UHVDC transmission system in a UHV AC/DC hybrid system caused by the faults occurred in UHVAC system, the RTDS closed-loop test system of a certain UHVDC transmission project is utilized to research the transient response characteristic of DC protection under AC faults and the malfunction of DC protection caused by AC faults. The response mechanism of DC protection to AC faults is revealed by two aspects, namely the similarity between AC faults and DC faults as well as the imperfection of both protection principle and setting method of DC protection. Based on this response mechanism, the types of DC protections, which can reflect AC faults in principle, are summarized. Combining with RTDS experimental data of a certain UHVDC transmission system, the low-voltage characteristics of AC and DC system under faults occurred in AC systems at both sides of DC system and the malfunction of DC protection due to current unbalance characteristics are analyzed in detail. The malfunction mechanism of DC low-voltage protection, valve group differential protection and bridge differential protection under AC faults is analyzed in depth, and corresponding improvement suggestions are put forward.