高压直流线路短路故障行波保护动作概率计算与分析方法

Action probability calculation and analysis method for travelling-wave protection caused by short-circuit faults on HVDC transmission lines

行波保护是高压直流线路的主保护,直流线路发生短路故障时保护的正确动作对保证系统安全有重要作用。然而由于该保护利用故障初期暂态电气量构成保护判据,实际的行波保护方案对区内短路故障的判别具有很强的不确定性,或概率性。为定量描述这种概率性,提出了一种高压直流线路短路故障行波保护动作概率计算与分析方法。即在充分考虑实际行波保护动作逻辑及系统运行方式的基础上,综合计及故障类型、故障位置、过渡电阻、故障时刻等不确定因素的影响,基于Latin超立方抽样技术对现有行波保护方案的动作概率进行计算。算例以云广±800 kV特高压直流输电实际工程中的行波保护方案为研究对象,探明了故障条件中各因素对行波保护动作概率的影响程度,分析了运行方式变化带来的不利影响。

Travelling-wave Protection（TWP） is the main protection of HVDC transmission lines, and it is important to act correctly for TWP to ensure the system safety when a DC-line-short-circuit fault occurs. However, since TWP uses the transient electrical quantities in the initial fault stage to construct its action criteria, the results of internal-fault discriminant from a practical TWP scheme are highly uncertain, or probabilistic. To quantitatively describe this probability, this paper proposes an action probability calculation and analysis method for TWP against DC-lineshort-circuit faults. Based on the actual TWP operation logic and different system operation modes, this method considers four uncertain fault condition factors, including fault type, fault point, fault resistance and fault time, and adopts Latin hypercube sampling technique to calculate related probability indexes. In the numerical examples, the actual TWP scheme in Yun Guang ±800 kV UHVDC system is taken as the study object, and the influences of different fault condition factors and the changed operation modes to TWP are analyzed.