电力系统自动化
電力繫統自動化
전력계통자동화
AUTOMATION OF ELECTRIC POWER SYSTEMS
2011年
23期
52-58,98
,共8页
贺家李%贺继红%王小玲%徐陆宇%薛士敏
賀傢李%賀繼紅%王小玲%徐陸宇%薛士敏
하가리%하계홍%왕소령%서륙우%설사민
特高压输电%过电压%自励磁
特高壓輸電%過電壓%自勵磁
특고압수전%과전압%자려자
ultra-high voltage transmission%overvoltage%self-excitation
发电机带长线路运行时,由于线路分布电容电流的助磁作用,常引起发电机的自励磁。特高压输电线分布电容大,引起自励磁的可能性更大。对发电机自励磁的研究,一般从参数谐振和参数周期性变化的角度进行分析,未涉及自励磁产生的根源。文中认为发电机自励磁的根源是电容性电流的助磁作用产生的正反馈使系统发生自激振荡。对励磁回路断开且xd=xq的理想隐机发电机,在无参数的周期性变化且只考虑相同的直轴和交轴阻尼绕组的情况下,用劳斯稳定判据证明了线路电容达到一定值时产生自激振荡自励磁的必然性,并用实例仿真进行了证明。文中对发电机—特高压输电线系统末端甩负荷引起的自励磁过电压进行了研究,并研究了在甩负荷瞬间投入金属氧化物避雷器(MOA)以抑制过电压的可行性。
髮電機帶長線路運行時,由于線路分佈電容電流的助磁作用,常引起髮電機的自勵磁。特高壓輸電線分佈電容大,引起自勵磁的可能性更大。對髮電機自勵磁的研究,一般從參數諧振和參數週期性變化的角度進行分析,未涉及自勵磁產生的根源。文中認為髮電機自勵磁的根源是電容性電流的助磁作用產生的正反饋使繫統髮生自激振盪。對勵磁迴路斷開且xd=xq的理想隱機髮電機,在無參數的週期性變化且隻攷慮相同的直軸和交軸阻尼繞組的情況下,用勞斯穩定判據證明瞭線路電容達到一定值時產生自激振盪自勵磁的必然性,併用實例倣真進行瞭證明。文中對髮電機—特高壓輸電線繫統末耑甩負荷引起的自勵磁過電壓進行瞭研究,併研究瞭在甩負荷瞬間投入金屬氧化物避雷器(MOA)以抑製過電壓的可行性。
발전궤대장선로운행시,유우선로분포전용전류적조자작용,상인기발전궤적자려자。특고압수전선분포전용대,인기자려자적가능성경대。대발전궤자려자적연구,일반종삼수해진화삼수주기성변화적각도진행분석,미섭급자려자산생적근원。문중인위발전궤자려자적근원시전용성전류적조자작용산생적정반궤사계통발생자격진탕。대려자회로단개차xd=xq적이상은궤발전궤,재무삼수적주기성변화차지고필상동적직축화교축조니요조적정황하,용로사은정판거증명료선로전용체도일정치시산생자격진탕자려자적필연성,병용실례방진진행료증명。문중대발전궤—특고압수전선계통말단솔부하인기적자려자과전압진행료연구,병연구료재솔부하순간투입금속양화물피뢰기(MOA)이억제과전압적가행성。
Self-excitation of generators may occur due to the large capacitive currents of the long distance ultra-high voltage(UHV) transmission lines connected to a generator.It may cause severe overvoltage and consequently damage electric power equipments and insulators of the transmission lines.As such,its original cause,mechanism of development and methods of suppression must be carefully studied.In literature,generator self-excitation is generally considered as parametric resonance due to the cyclical variations of the parameters of the generator.This paper denotes that the original cause of the generator self-excitation is the positive feedback action due to the additive magnetizing effect of the capacitive current on the dynamic system consisting of generators,transformers and transmission lines.This standpoint is proved by using Routh stability criterion and digital simulation of an ideal non-salient pole generator,whose xd=xq,with excitation circuit opened and the same damper windings on the direct and quadrature axis.The self-excitation also occurs in such conditions although there are no cyclical variations of the parameters of the generator.Besides,the theoretical study and digital simulation of self-excitation overvoltage due to load rejection at the end of the actual generator-UHV transmission-line system are also given.The feasibility of overvoltage suppression by inserting metal oxide arrester(MOA) at the moment of load rejection is proven as well.