基于故障后稳态电压安全约束的新能源并网系统电压支撑强度量化分析方法  

Quantitative Analysis Method for System Strength of Renewable Energy Generation Grid-connected System Based on Post-fault Steady-state Voltage Security Constraint

作　　者：孙华东 于琳 赵兵 SUN Huadong;YU Lin;ZHAO Bing(State Key Laboratory of Power Grid Safety and Energy Conservation(China Electric Power Research Institute),Haidian District,Beijing 100192,China)

机构地区：[1]电网安全与节能国家重点实验室(中国电力科学研究院有限公司),北京市海淀区100192

出　　处：《中国电机工程学报》2023年第9期3322-3331,共10页Proceedings of the CSEE

基　　金：国家重点研发计划项目(2021YFB2400800)。

摘　　要：新能源并网系统电压支撑强度低,故障清除后易发生稳态电压安全问题,新能源机组反复进入低电压穿越,严重时脱网,影响系统的安全运行。该文计及新能源并网系统各馈入支路之间存在的相互作用,采用短路比(short-circuit ratio,SCR)表征新能源并网系统电压支撑强度,建立故障后稳态电压安全约束下的电压支撑强度量化分析模型。首先,通过分析并网点电压与新能源规模、系统短路容量之间的关系,提出单馈入系统的故障后低电压数学分析模型,在此基础上计及各支路之间的相互影响,建立多馈入系统数学分析模型,提高了分析模型的实用性;然后,采用短路比表征电压支撑强度,量化分析新能源并网系统的电压支撑强度对故障后稳态电压安全问题的影响程度,系统短路容量越小,新能源规模越大,电压支撑强度越低,故障后稳态电压安全问题越严重;进一步,以0.9pu作为故障后稳态电压安全约束,提出满足该约束时系统最小短路容量以及新能源最大并网规模的计算方法;最后,通过算例对故障后稳态电压安全数学分析模型、系统最小短路容量,以及新能源最大并网规模量化方法的准确性进行验证,为提高新能源并网系统运行的安全性提供参考。The strength of the power system with renewable energy generation(REG)is weak and the post-fault steady-state voltage security problem is prone to occur.Considering the interaction among the multi-infeed branches,a quantitative analysis model based on the voltage security constraint is established by using the short-circuit ratio(SCR)as system strength index.First,a post-fault steady-state voltage analysis model of the single-infeed system is established.Furthermore,the analysis model of the multi-infeed system is established to improve the practicability considering the influence among the multi-infeed branches.Then,the correlation between the SCR and the post-fault steady-state voltage security problem is quantitatively analyzed.Furthermore,taking 0.9pu as the voltage security constraint,the calculation method of the minimum short-circuit capacity and the quantification method of the maximum REG scale are proposed.Finally,the accuracy of the post-fault steady-state voltage security analysis model,the minimum short-circuit capacity and the quantification method of the maximum REG scale are verified by simulations,which provides the reference for the safe and stable operation of the power system with REG.

关 键 词：故障后稳态电压安全 电压支撑强度 新能源并网规模 短路容量 

分 类 号：TM73[电气工程—电力系统及自动化]