【作者】 徐松晓；

【导师】 李永丽； 贺家李；

【作者基本信息】 天津大学 ， 电力系统及其自动化， 2007， 硕士

【摘要】 国家发展改革委员会和国家电网公司已决定建设我国第一条“晋东南-南阳-荆门”1000kV的特高压交流输电线路示范工程,并将于2008年投入运行。这对我国电力系统的发展起着重要作用,是我国电力工业发展新的里程碑。为了保证特高压电网运行的稳定性,要求研制新的性能优良工作可靠的继电保护装置。电流相位差动保护具有不受系统振荡影响、在非全相状态下能正常工作、结构简单、不用电压量等巨大优点,但无选相功能。受线路分布电容电流影响大,不能用于长距离特高压输电线路。本文提出了基于输电线贝瑞隆法的特高压长线路分相电流相位差动保护新原理。此原理完全消除了线路分布电容电流对分相电流差动保护的影响,保护灵敏度得以极大提高。贝瑞隆模型是一种比较精确的输电线路模型,它反映了输电线路内部无故障时两端电压电流之间的关系,而线路内部故障时,相当于在故障点增加了一个节点,这种关系被破坏。本文提出利用这一差别区分线路内部和外部故障,构成一种新的差动保护原理。这种新的保护原理自动地考虑了电容电流地影响,不再需要进行电容电流补偿。详细介绍了利用贝瑞隆模型计算输电线路故障的方法,推导了实现分相电流相位差动纵联保护的判据,综合分析了各种故障状态下保护的动作情况,解决了各种故障下的故障判别以及特高压线路上的大电容电流影响等问题。还提出了用于故障后1～2个周波的基于电流故障分量的分相电流相位差动保护新原理,大大提高了保护承受过渡电阻的能力和动作速度。用ATP和MATLAB仿真证明了该原理的正确性和用于特高压输电线的优越性。更多还原

【Abstract】 The National Development and Reform Commission (NDRC) and State GridCorporation of China (SGCC) had decided to construct the first UHV transmissionlineofAC 1000kVfrom Jin-southeast toNanyangandthentoJingmen,andit willgointoactionin2008. Itwillpromotethedevelopmentofpowersystemofthenation. Inorder to ensure the UHV transmission lines running stability, a new high-poweredrelayprotectiondevicewithhighreliabilitymustberesearchedanddeveloped.Current phasedifferential protectionwill not beaffectedbypowerswingandtwophase operation condition of transmission line. It is more simple in structure withoutneed of voltage information. But it will seriouslybe affected bydistributed capacitivecurrent of transmission line, and it does not possess Phase Selection function. So thatcurrent phase differential protection can not be used on long UHV transmission lines.SoanovelprincipleofphasesegregatedcurrentphasedifferentialprotectionforUHVtransmissionlinesbasedonBergeronmodelisproposedforthefirsttimeinthispaper.The proposed principle will not be affected by distributed capacitive current and ismore sensitive and reliable than traditional current phase differential protection.Bergeron model is an accurate transmission line model, it is a de-coupled method ofcomputing voltage and current of two points on transmission lines in their normaloperation condition including outside faults of the line. When there are some innerfaultsintherangeoftransmissionline,themodel willbenottrue.Thisdiscriminationcanbeusedtoidentifywhetherthereisfaultinthetransmissionlineornot.Thenovelprinciple has considered the influence of distributed capacitive current, so it does notneed capacitive current compensation. In this paper, method of fault analysis oftransmission lines based on Bergeron model and analysis of protection operation incase of various types of faults are introduced. The paper has also proposed anothernew principle of phase segregated current phase differential protection based on faultcomponent during 1~2 periods after fault inception to improve the ability of bearingtransition resistance. Simulation results by ATP and MATLAB proved that theprincipleiscorrectandhasbestperformanceswhenusedonUHVtransmissionlines.更多还原