摘要
±800 kV乌东德特高压多端混合直流输电工程是重大电力行业科技示范项目。其中,送端昆北站汇集了龙开口、鲁地拉等水电站,电站与换流站之间输电线路长,换流站运行压力大,因而对其高压交流断流器的参数要求提出了挑战,依据工程具体实际来制定断路器的技术参数显得十分重要。以乌东德电站送电广东、广西(昆柳龙)直流输电工程为依托,对昆北站中使用的交流断路器工作条件进行了研究。以交流系统及换流站相关数据为依据,如交流系统短路电流,换流变参数,交流滤波器和并联电容器小组、大组参数等。首先给出了昆北换流站的交流换流器分布概况、数量与说明。然后提出了选相合闸的作用和配合逻辑。为了得到交流滤波器和并联电容器大组/小组断路器和换流变断路器的特殊要求数据,通过理论分析和计算得到了额定单个和背靠背电容器组开断电流的大小。实验仿真软件选取PSCAD/EMTDC,模型是由HVDC换流器、换流变、交流滤波器及并联电容器组、交流母线避雷器组成的三相系统,模拟单组断路器的开断、切小组断路器降低交流母线FFOV以及孤岛运行模式等情况下的最大TRV值。从而确定了昆北换流站高压交流断路器的选型要求:(1)交流滤波器小组断路器和换流变断路器应安装选相合闸装置,以减小断路器合闸涌流;(2)交流滤波器和并联电容器大组/小组断路器必须满足工程实际的特殊要求,电容器组涌流峰值/涌流频率计算值,考虑选相合闸装置1 ms误差,昆北站为4.9 kA/2401 Hz;(3)交流系统并联网运行时,交流滤波器大组和小组断路器的最大TRV计算结果为:昆北站交流滤波器小组断路器1319 kV,故障工况及策略为双极运行时,发生单相接地故障,接地故障后100 ms切除线路,1 s后重合闸失败,切除故障线路,同时闭锁双极,再延迟100 ms切除小组滤波器;(4)昆北站交流断路器型式:孤岛方式最苛刻工况下采用分时切小组交流滤波器策略,A、B及C型ACF小组断路器耐受TRV能力需分别满足1387 kV、1430 kV及1367 kV以上,大组ACF断路器耐受TRV能力需满足1230 kV及以上;当在各型滤波器主电容侧安装避雷器后,A、B及C型ACF小组断路器的TRV分别为1205 kV、1122 kV、1201 kV,大组、小组ACF断路器均选择双断口断路器,其TRV耐受能力为1470 kV及以上。本案例可为特高压多段混合直流输电的高压交流断路器的选型提供参考。
±800 kV Wudongde UHV multi-terminal hybrid DC transmission project is a major power industry demonstration project.Among them,the sending end of Kunbei Station brings together hydropower stations such as Longkaikou and Ludila.The transmission line between the station and the converter station is long,and the operation pressure of the converter station is large.Therefore,the parameter requirements of its high-voltage AC current breaker are challenged.It is very important to formulate the technical parameters of the circuit breaker ac-cording to the specific engineering practice.Based on the DC transmission project of Wudongde Hydropower Station to Guangdong Guangxi(Kunli-ulong),the working conditions of AC circuit breakers used in Kunbei Station are studied.The research work is based on the relevant data of AC system and converter station,such as short circuit current of AC system,con-verter transformer parameters,AC filter and shunt capacitor large/group parameters,etc.Firstly,the distribu-tion,quantity and description of AC converters in Kunbei converter station are given.Then the function and co-ordination logic of phase selection closing are proposed.In order to obtain the special requirement datas of AC filter and shunt capacitor large/group circuit breakers and converter circuit breakers,the breaking current of rated single and back-to-back capacitor banks is obtained by theoretical analysis and calculation.PSCAD/EMTDC is selected as the simulation software to simulate the three-phase system composed of HVDC converter,converter transformer,AC filter,shunt capacitor bank and AC bus arrester.The maximum TRV is simulated under the conditions of single group circuit breaker breaking,group circuit breaker cutting down AC bus FFOV and island operation mode.The selection requirements of high voltage AC circuit breaker in Kunbei converter station are summarized and determined:(1)AC filter circuit breaker and converter circuit breaker should be installed phase selection closing device to reduce circuit breaker closing inrush current.(2)AC filter and shunt capacitor large/group circuit breaker must meet the special requirements of engineering practice.The calculation value of peak/frequency of inrush current of capacitor bank is 4.9 kA/2401 Hz,considering the 1 ms error of phase selection closing device.(3)When the AC system is connected to the network,the maximum TRV calculation results of AC filter group and group circuit breakers are as follows:1319 kV AC filter group circuit breakers in Kunbei Station.When the fault condition and strategy are bipolar operation,single-phase grounding fault occurs,and the line is removed after 100 ms of grounding fault.After 1 s,the reclosing failure is failed,the fault line is removed,the bi-polar is locked,and the group filter is removed after 100 ms.(4)Types of AC circuit breakers in Kunbei Substation:the time-sharing cut-off group AC filter strategy is adopted under the most severe working condition of island mode.The TRV tolerance of A,B and C ACF group circuit breakers should meet 1387 kV,1430 kV and 1367 kV,respectively.The TRV tolerance of large group ACF circuit breakers should meet 1230 kV and above.When the arrester is installed on the main capacitor side of each type of filter,the TRV of A,B and C ACF group circuit breakers are 1205 kV,1122 kV and 1201 kV,respectively.The double fracture circuit breakers are selected for large group and group ACF circuit breakers,and the TRV tolerance is 1470 kV and above.This case can provide reference for the selection of high voltage AC circuit breakers for UHV multi-segment hybrid DC transmission.
作者
徐攀腾
尚茂林
朱博
宋述波
李倩
樊友平
XU Pan-teng;SHANG Mao-lin;ZHU Bo;SONG Shu-bo;LI Qian;FAN You-ping(China Southern Power Grid Co.,Ltd.,Guangzhou Bureau of UHV Transmission Company,Guangzhou 510700,China;School of Electrical and Automation,Wuhan University,Wuhan 430072,China)
出处
《电力学报》
2021年第3期191-199,227,共10页
Journal of Electric Power
基金
“南方电网乌东德电站送电广东、广西特高压多端柔性直流示范工程”项目研究成果
国家重点研发计划项目(2016YFB0900903)
