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输电线路自适应重合闸研究与仿真
Research and Emulation of Adaptive Reclosure in Transmission Lines
【作者】 勤格勒图；
【导师】 刘文里；
【作者基本信息】 哈尔滨理工大学 ， 高电压与绝缘技术， 2009， 硕士
【摘要】 电力系统输电线路中的短路故障大多数是瞬时性故障,因此,自动重合闸技术已经广泛应用于电力系统中,大大提高了供电的可靠性。但传统的自动重合闸技术采用定时重合,不对故障进行判断,即不论瞬时性故障还是永久性故障,自动重合闸都会动作。因此,在故障尚存时可能重合,对系统造成二次冲击,不利于系统的稳定,而且可能会对电力系统和系统中的设备造成很大的危害。为了避免输电线路采用自动重合闸时,重合于永久性故障所造成系统稳定破坏等重大系统灾难,在微机保护的基础上,自适应重合闸的概念应运而生,但目前自适应重合闸尚处于理论探索阶段。本文提出了一种不同于现有故障类型判别的思路,通过考察线路单相接地故障的物理过程,分析故障电弧特性对故障相阻抗角的影响,利用MATLAB中PSB模块进行仿真。通过比较永久性故障和瞬时性故障,阻抗角的不同变化,提出了识别输电线路永久性故障和瞬时性故障的判据。所提判据在时间和准确性上要优于传统的基于故障后线路开关开断后故障线路残压幅值的判别法,并经动态仿真验证了其正确性。最后,论文分析了目前尚存在的不足和需要进一步完善所做的工作。
【Abstract】 The faults of transmission lines are most temporary ones in power system. So, the auto-reclosure technique has been widely applied in real power systems now. It is an effective method to improve the stability and synchronism of power systems. However, the present auto-reclosure technique normally employs a prescribed reclosure time, that is, the breaker is re-closed after a fixed period following a tripping operation without estimating fault nature. Main problem with the conventional reclosure scheme is a risk of a second shock to the system in the case of a permanent fault, when may lead to system oscillation.In order to avoid the power system disaster caused by reclosing on the permanent fault of transmission line , adaptive autoreclosure based on microproeessor-based protection arises at the historic moment,but is still in the stage of theory study.This paper has proposed one new way of thought of differentiating the fault type. After observing the physical course of the single-phase grounding of transmission line,analyzing the different characters of phases affected by the arc between the temporary faults from permanent ones during the fault period from the moment that single- phased grounding occurs to the moment that line breakers work , and emulating by PSB in MATLAB ,we can distinguish temporary fault from permanent one through the phase form. As far as time cost and accuracy are concerned,this criterion based on wave form discernment is superior to the traditional one based on the transmission 1ine voltage amplitude sampled after breakers work and has been verified its exactness by dynamic emulation.Finally, the disadvantages of existent schemes and proposals to improve the criteria are pointed out.