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柔性直流电网故障暂态电压和电流特征分析方法

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  • 国家科技期刊平台
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对柔性直流电网故障后的暂态电压和电流特征进行准确分析是设计新型故障保护方案的理论基础,现有利用首行波的故障特征分析方法未能有效反映故障点对故障行波多次折射和反射的影响,在近端故障时将产生较大的误差.利用建立的柔性直流电网故障后的等值电路图,求解得到不同位置故障点的初始故障电压、不同位置的折射和反射系数、以及故障点线模-地模耦合转化系数.提出了一种考虑行波多次折射和反射之后故障点等效故障电压的计算方法,并联合求解得到的系统中各位置故障电压和电流的传递函数,得到故障后暂态电压和电流的数值表达式.在PSCAD/EMTDC搭建环状四端柔性直流电网仿真模型模拟故障,通过仿真与理论计算的对比结果验证理论推导的正确性.
A Features Analysis Method of the Transient Fault Voltages and Currents for Flexible DC Grids After DC Line Faults
Accurate analysis of transient features of voltages and currents for fllexible DC grids after DC faults is the theoretical basis of fault protection scheme design.The existing fault characteristic analysis methods using the initial traveling wave fail to effectively reflect the influence of the fault point on multiple refractions and reflections of fault traveling waves,which will produce large errors in case of a close-in fault.Using the established fault equivalent circuit of the flexible DC grid,the initial fault voltage at the fault point,the refraction and reflection coefficients at different positions,and the line-mode and ground-mode coupling coefficient at the fault point are acquired.A calculation method of the equivalent fault voltage at the fault point is proposed considering multiple refractions and reflection of the traveling wave.The numerical expressions of the transient voltages and currents can be obtained with the transfer functions of the fault voltages and currents at different positions.To simulate the fault,a ring topology four-terminal flexible DC grid simulation model is built in PSCAD/EMTDC.The correctness of the theoretical derivation is verified by comparing the simulation value with the theoretical calculation value.

flexible DC gridsfault voltage and current traveling wavesnumerical expressionmultiple refractions and reflectionstransfer function

余修勇、顾菊平、张新松、茅靖峰、肖立业

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南通大学电气工程学院,江苏省 南通市 226019

中国科学院电工研究所,北京市海淀区 100190

柔性直流电网 故障电压和电流行波 数值表达式 多次折射和反射 传递函数

国家自然科学基金项目国家自然科学基金项目江苏省高校自然科学研究项目南通市基础科学研究项目

U20662035187711223KJB470034JC12022050

2024

10.13335/j.1000-3673.pst.2023.0816

电网技术
国家电网公司

电网技术

CSTPCD北大核心
影响因子：2.821
ISSN：1000-3673
年,卷(期)：2024.48(7)