摘要
发现三相重合闸投入时序对750kV输电线路的合闸过电压有较大影响。为此,分别基于无补偿和两端经并补补偿的750kV输电线路分布参数模型,对三相重合于三相、单相故障时的过电压水平进行了详细解析,藉此从抑制合闸过电压的角度提出了重合闸时序的整定策略。1)合于三相瞬时故障时,合闸顺序与计划性合闸一致。①无补偿线路应由大电源侧先重合;②而两端经并补补偿线路,补偿度小于文中给出的临界补偿度时,由大电源侧首先重合可降低合闸过电压。2)而合于单相故障时,情况较为复杂。①对于无补偿线路,分闸顺序由故障点与系统和线路电抗的关系决定,由小电源、远故障点侧首先分闸,可降低线路重合前残压;大电源、近故障点侧首先重合,可减小重合闸过电压;②对于经补偿线路,线路两端电源容量、故障点位置和补偿度均会影响三相重合闸过电压峰值,补偿度小于临界补偿度时,应由大电源、近故障点侧首先重合,反之,应由小电源、远故障点侧先重合;近故障点与大电源未在同侧时,合闸顺序由实际工频电压升高系数与单相接地引起的电压升高系数2者乘积的大小决定。大量PSCAD仿真表明重合时序整定策略正确、有效。
The sequence of three-phase re-closure greatly influences the closing voltage of 750 kV transmission line. Therefore, on the basis of distributed-parameter models of 750 kV transmission line with and without shunt reactors respectively, we analyzed voltage levels of three-phase reclosing on a three-phase fault in a single-phase fault, and set a strategy for reclosing sequence in the prospective of constraining reclosure over-voltage. The results reveal that, for reclosing to three-phase transient fault, the reclosing sequence is consistent with planned closing： a） for a transmission line in the absence of shunt reactor, large sources should reclose first; b） for a transmission line in the presence of shunt reactor, closing on the large source side when the compensation degree is less than the given critical value can suppress closing voltage. The results also reveal that, it is more complex for reclosing at single- phase fault： a） for a transmission line in the absence of shunt reactor, the closing sequence should be determined according to the conditions of fault point and the line impedance, i.e. tripping at small source side as well as far- from fault side firstly can decrease the residual voltage of sound-phase, while tripping large source side and close-to- fault side firstly decreases the closing voltage; b） for a transmission line in the presence of shunt reactor, peak value of three-phase reclosing over-voltage is affected by capacity of system, fault point and compensation degree; specifically, when compensation degree is less than its critical value, large source and close-to-fault side should reclose first, otherwise the small source and far-from-fault side should reclose at first; c） if the large source side is not the same as close-to-fault side, the reclose sequence depends on the product of the coefficient of increment of power-frequency voltage and the coefficient of increment of voltage induced by single-phase fault. The proposed setting strategy of reclosing sequence is verified by multiple simulations in PSACD.
出处
《高电压技术》
EI
CAS
CSCD
北大核心
2013年第12期3059-3068,共10页
High Voltage Engineering
基金
国家自然科学基金(51367009
50977039
50847043
90610024
51007035)
云南省自然科学基金(2005F0005Z
2009ZC016M)
云南省教育厅基金重点项目(2010Z105)
昆明理工大学人才培养基金(2010-03
KKSY201204058)~~
关键词
三相重合闸
重合时序
750
KV
合闸过电压
并联补偿
故障距离
电源容量
three-phase reclosure
reclosure sequence
750 kV
closing over-voltage
shunt compensation
fault distance
power capacity
