适用于不对称故障短路计算的新能源场站实用化建模方法

Practical Equivalence of New Energy Generator Field for the Asymmetrical Fault Short Circuit Calculation

继电保护整定计算是开展电力系统保护定值整定和校核的重要工具。故障时新能源出力的强受控性及控制策略的差异性使得传统整定计算结果的准确性下降。新能源接入比例逐渐升高,但目前依然缺乏面向保护整定计算的实用化新能源等值建模方法,尤其缺乏针对不对称故障时新能源不同控制策略下的通用建模手段。该文以新能源在不对称故障时采取的正负序分量控制策略为依据,将新能源的单机输出特性分为了3种主要等值方式,并分别提出了面向实际工程中差异化新能源控制策略的单机等值方法,等值效果得到了具备实际工程中光伏、风机输出特性的封装模型的佐证。在此基础上提出了新能源场站聚合等值建模方法,最终通过短路计算验证了该实用化等值建模方法的有效性和准确性。

Calculating the relay protection settings is an important tool to carry out protection setting and verification.During a fault state,the controlled outputs of new energy generators(NEGs)and the differences in their control strategies could make traditional setting calculations unreliable.As the proportion of NEG gradually increases in protection setting calculation,there is still a lack of its practical equivalent modeling method,especially a common modeling method for the unbalanced fault condition.This paper divides the stand-alone modeling of NEG into three main equivalence methods according to the NEG control strategies of positive and negative sequence components in asymmetric faults.Considering the control strategies in actual projects,the stand-alone equivalence methods for the three conditions are proposed,respectively,demonstrated by the PVs and wind turbines in actual systems.Based on stand-alone equivalence methods,the NEG field's aggregation equivalence modeling method is proposed.Finally,the accuracy of models is verified by short-circuit calculations.