Reliability Risk Assessment of Differential Protection of Converter Transformer Under Influence of Fault-induced Inrush Current

被引：0
|
作者：
Zheng T. [1 ]
He R. [1 ]
Yang X. [1 ]
Guo X. [1 ]
Luo M. [2 ]
机构：
[1] State Key Laboratory for Alternate Electrical Power System With Renewable Energy Sources (North China Electric Power University), Changping District, Beijing
[2] State Grid Ningxia Electric Power Limited Company, Yinchuan
来源：
Dianwang Jishu/Power System Technology | 2021年 / 45卷 / 11期
关键词：
Converter transformer; Differential protection; Fault-induced inrush current; Risk assessment;
D O I：
10.13335/j.1000-3673.pst.2020.2103
中图分类号：
学科分类号：
摘要：
The mixing AC-DC power grid makes the fault characteristics of the power grid extremely complicated. When a single-phase-to-ground fault occurs on the converter valve side, the fault current is biased to the time axis due to the single guiding characteristic of the converter valve, and the DC component will cause the biased flux of the converter core, leading to the saturation area of the flux of core and fault-induced inrush current (FIIC). In this paper, a risk assessment model of the converter transformer differential protection under the influence of FIIC is established based on the risk assessment theory of the power system. The comprehensive risk index is defined as the product of the probability of FIIC and the severity of the risk caused by the FIIC to the differential protection. The probabilities of the FIIC under different fault conditions are obtained by analyzing the mechanism of the FIIC, and the proportion of the time that the second harmonic content exceeds or falls below the threshold value is used as the index to evaluate the severity of the risk of rejection or misoperation caused by the FIIC to the differential protection. The risk grades are classified according to the comprehensive risk index values. Finally, a risk assessment model of the reliability of differential protection is verified by PSCAD/EMTDC simulation. © 2021, Power System Technology Press. All right reserved.
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页码：4490 / 4497
页数：7
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