特高压输电线路的过电压研究与仿真

【作者】 张友华；

【导师】 周杰娜； 刘晓波；

【作者基本信息】 贵州大学 ， 电力系统及其自动化， 2008， 硕士

【摘要】 随着我国电力工业的发展,发展特高压输电已经势在必行。我国已经确定了未来以特高压作为骨干输电网架,其安全可靠性对于全系统的安全可靠性起着决定性的作用,故对其继电保护、自动控制和可靠性等性能要求极高。特高压设备所能承受的过电压裕度比超高压要小,从而发生过电压造成设备损失非常巨大,特高压输电线路过电压的大小及其限制措施成为发展特高压输电技术所必须研究的课题。为此,本文详细的研究分析了特高压输电线路的过电压产生规律及其影响因素,研究了不同的限制措施对过电压大小的影响。6本文首先理论分析了工频过电压和操作过电压的产生机理;然后根据特高压输电实例应用电磁暂态分析软件包PSCAD/EMTDC进行了一系列仿真研究。对于工频过电压,着重研究了单端电源与长线相连、双端电源与长线相连、接地故障等情形下,不同的并联电抗器运行方式对工频电压升高的抑制作用;然后研究了SVC对特高压输电系统的影响,论证了SVC改善电压质量的能力。对于操作过电压,仿真研究了各种情况下的跳闸过电压和合闸(重合闸)过电压的大小和规律,详细仿真分析了带并联电阻的断路器和金属氧化物避雷器对操作过电压的限制作用。本文通过理论与仿真研究,得出了特高压输电线路过电压现象的一般规律,提出了限制过电压的有效措施和保护控制策略,得出了一些相关结论。更多还原

【Abstract】 Along with the development of electric power industry, it is necessary to develop the UHV transmission system in our country. At present, the UHV transmission has been the future backbone of electric power grid in China, and its security and reliability play a critical role in the whole power system. Therefore, the relay protection, automatic control system should have excellent performance and high reliability. The over-voltage margin borne by UHV equipment is smaller than the EHV, and the loss caused by over-voltage faults on UHV equipment is greater than the EHV’s, too. The over-voltage of UHV transmission lines and its restrictions have been the critical technology for the development of UHV transmission. In this paper, the over-voltage factor is researched and simulated for UHV transmission lines as well as the different restrictions to limit the over-voltage. Moreover, the impact of various methods of the over-voltage restrictions is researched, too.At first, a theoretical analysis for the mechanism of power frequency over-voltage and switching over-voltage is presented in this paper. A series of simulation and research for a UHV transmission in practice is conducted with the electromagnetic transient analysis software package PSCAD/EMTDC. As the power frequency over-voltage, the distributing voltage along the line with different mode of shunt reactor connection has been analyzed under different operation modes, including the conditions single or double sources connected with long line and fault to ground. The influence on the UHV transmission system with SVC is demonstrated as well as its ability to improve the voltage quality. On the other hand, simulation of the opening or closure processes which caused the switching over-voltage is also studied in this paper, and some exact data and operation rules for such over-voltage are obtained. The characteristic of breakers with a parallel resistor is simulated as well as the restrictions role to the switching over-voltage of MOA.After the theory and simulation research, the common rules of over-voltage at UHV transmission line is obtained, the methods of restrictions on the over-voltage is proposed as well as the protection measures, the effective control strategy is designed, and some relevant conclusions is given in the end of the paper.更多还原