高压故障限流器系统应用研究及研制

Research and Development on Application of High Voltage Fault Current Limiter

随着中国电网容量不断提升,短路电流超标问题日益严重。文中以西北某变电站为例,首先分析了220 kV母线三相短路故障下各支路的短路电流分布情况,据此提出了3种不同的短路电流限制方案,并对方案的优缺点进行了比对分析。然后搭建了变电站周边电网的电磁暂态仿真模型,分析了短路电流抑制效果,提出了FCL故障动作及重合的控制策略原则,并定量校核了系统暂稳态性能、继电保护动作行为的影响。最后根据系统仿真得出来的短路电流、暂态过电压等结果,进行了FCL快速开关、限流电抗器及控制装置设计。研究结果表明,FCL能够有效将220 kV母线三相短路电流限制到51.27 kA,限流幅度达18.6%;加装FCL后不会影响系统稳态潮流分布和暂态系统稳定;FCL动作对继电保护影响整体可控。通过RTDS动模试验验证了定量分析的正确性;FCL快速开关采用2个72.5 kV断口串联冗余设计,提高了设备可靠性;限流电抗器按照短时耐受电流设计,可大幅降低成本和占地;控制装置故障检测判断时间小于3 ms,保证了限流保护动作的准确性与及时性。现场人工接地短路试验表明,所设计的FCL整体起效时间9.2 ms,电流限制效果显著,且未对系统稳定性、继电保护等产生不利影响。

With the continuous increase of power grid capacity in China,the problem of short circuit current exceeding standard is becoming more and more serious. In this paper,a substation in Northwest of China is taken as an example,the short-circuit current distribution of each branch under three-phase short-circuit fault of 220 kV bus is analyzed firstly. On this basis,three different kinds of short circuit current limitation schemes are proposed and the advantage and dis-advantages of the schemes are compared and analyzed. Then,the electromagnetic transient simulation model of the power grid around the substation is set up. The suppression effect of short-circuit current is analyzed. The control strategy principle of FCL fault action and re-closing is proposed,and the influence of system transient and steady performance as well as relay protection action behavior is quantitatively validated. Finally,the FCL fast switch,current limiting reactor and control device are designed in accordance with the results of short-circuit current and transient over-voltage which are obtained from the simulation system. The research results show that the FCL can effectively limit the three-phase short-circuit current of 220 kV bus to 51.27 kA,with the current limiting amplitude up to 18.6%. The steady power flow distribution and transient system stability will not be affected after installation of FCL. The influence of FCL action on relay protection can be well handled. The correctness of quantitative analysis is verified by a real time digital simulation(RTDS)test. The FCL fast switch adopts redundancy design with two 72.5 kV break in a series connection,which improves reliability of the equipment. The current limiting reactor is designed in accordance with the short-time withstand current,which can greatly reduce the cost and foot print.The fault detection and judgement time of the control device is less than 3 ms,which guarantees the accuracy and timeliness of the current limiting protection. The artificial grounding short circuit test at site shows that the overall effective time of the designed FCL is 9.2 ms,with remarkable current limitation effect and without adversely influence on the system stability and replaying protection etc.