1000kV紧凑型输电线路的电气参数及电磁暂态分析

Analysis on Electrical Parameters and Eletromagnetic Transient of 1000 kV Compact Transmission Line

分析1 000 kV紧凑型线路的电气参数、工频过电压、潜供电流、操作过电压等,并与常规型线路进行比较。结果表明,紧凑型线路的自然功率较大,其电气参数的平衡性较好;为满足限制工频过电压和潜供电流的要求,紧凑型线路需要较大的高抗容量,其中性点小电抗的阻值也较大。研究发现,紧凑型线路高抗中性点电压较高,在算例中超过了特高压示范工程中相应的耐压水平;为此,建议适当提高线路高抗中性点的绝缘水平。此外,鉴于紧凑型线路的相间距离明显小于常规型线路,还应注意校核相间绝缘水平。必要时,可以考虑采用四星接法MOA来限制紧凑型线路的相间操作过电压。

Electrical parameters, power frequency overvoltages, secondary-arc currents, switching surges and so on of inverse triangle arranged 1 000 kW compact transmission lines are analyzed and compared with those of conventional types of transmission lines. Comparison results show that the compact transmission lines possess higher natural power and their electrical parameters are balanced better. To meet the demand on restricting power frequency overvoltage and secondary-arc current, it is necessary for compact transmission line to possess higher capacity of high voltage shunt reactor and larger reactance value of grounding reactor connected to the neutral. It is found in the research that the neutral voltage of high voltage shunt reactor for 1 000 kV compact transmission lines is high, and in the calculation example of this paper it exceeds corresponding withstand voltage level in ultra high voltage （UHV） pilot project. For this reason, it is recommended to properly enhance the insulation level of the neutral of high voltage shunt reactor for 1 000 kV compact transmission lines. Besides, in view of that the phase spacings of compact transmission lines are obviously less than those of conventional transmission lines, so it is necessary to check the inter-phase insulation level. If necessary, the four-star connection of metal oxide arresters （MOA） could be adopted to restrict the inter-phase switching surge of compact transmission lines.