110kV负荷线路单相断线故障特性分析及调度策略

Analysis of Single-phase Disconnection Fault Characteristics of 110kV Load Line and Dispatching Strategy

为了及时消除110 kV负荷线路单相断线故障对用户的影响,提出了基于正序、负序、零序分量的复合序网分析方法以及相应的调度策略。首先以A相断线为例进行基础理论推导分析,然后分别对110 kV负荷线路单相断线处的不同情况进行分析。最后根据分析结果并结合现场的调度规程提出相应的调度策略。研究分析结果表明断线相的电压与断口两侧是否接地有关;当负荷侧不接地系统发生单相断线且断口处两侧不接地时,断线相的相电压为正常电压的一半,若采用合母联的方式,会产生零序电流且其大小与负荷电流成正比,因此可能造成电源侧双回线零序保护动作,跳开双回线路。当发生单相断线时,值班调度员应根据电压、电流的情况正确选择采取合环倒路、停电倒路、拉停自投等方式减少故障影响。

To timely eliminate the bad impact on users by Single-phase break of the 110 kV load line,Complex sequence networks analysis method based on positive sequence,negative sequence and zero sequence and the corresponding scheduling strategy is proposed in this paper.Firstly,take A phase break line as an example to carry on the basic theory derivation analysis,and then respectively for 110 kV load line single-phase disconnection in different conditions are analyzed.Finally,the corresponding scheduling strategy is proposed according to the analysis results and the field scheduling rules.The analysis results show that the phase voltage of the broken line is related to whether the two sides of the fracture are grounded or not;When the load side ungrounded system occurs single-phase break and the two sides of the break are ungrounded,the phase voltage of the break phase is half of the normal voltage.If combined bus is used,zero sequence current will be generated and its magnitude is proportional to the load current.Therefore,it may cause the zerosequence protection action of the double circuit on the power side,and skip the double circuit.When single-phase line break occurs,the dispatcher on duty should choose the right way to reduce the influence of the fault according to the voltage and current.