摘要
介绍了10 k V配电网中性点经小电阻接地方式,通过对线路单相接地时的电流流向和保护整定方式的分析,讨论了一起线路高阻接地时接地变总后备误动的案例,并对线路和接地变零序电流整定值的配合方式给出了建议。结果表明,中性点经小电阻接地系统中,若作为整个10 k V系统总后备的接地变高压零流整定值小于出线Ⅱ段零序整定值,可能会造成总后备误动作。
Introduction was made to the low-resistance neutral point grounding mode in 10 kV power distribution grid. Analysis was made to the current direction and protection setting mode when the line single phase grounding. This paper discussed a case of total reserve unwanted operation of grounding transformer when the line high-resistance grounding and suggested that the line should fit for the setting value of grounding transformer zero-sequence current. The result shows that in the low-resistance neutral point grounding system, if the setting value of grounding transformer zero-sequence current acting as the 10 kV system total reserve is less than that of the outgoing line secondary section, the total reserve will turn up unwanted operation.
出处
《电工电气》
2015年第5期37-40,共4页
Electrotechnics Electric
关键词
小电阻接地
单相接地
总后备
误动
low-resistance grounding
single phase grounding
total reserve
unwanted operation
