±800kV/±500kV同塔混压双回直流输电线路的导线选型

Conductor Selection of Double-circuit DC Transmission Lines with Mixed-voltage ±800 kV/±500 kV on the Same Tower

目前尚无关于±800 k V与±500 k V同塔混压双回直流输电线路导线选型的可参考研究成果。为此,从电磁环境要求出发,采用电力线法、国际无线电干扰特别委员会(CISPR)和美国邦维尔电力局(BPA)经验公式法等国际公认且广泛使用的计算方法,研究了4种导线布置方式下不同导线型号组合的电磁环境指标(包括导线表面电场强度、电晕损耗、地面合成电场强度和离子流密度分布、可听噪声和无线电干扰等)。研究结果表明可听噪声是不同海拔高度下导线选型的主要控制因素。经技术经济比较后选择±500 k V导线在下层的导线布置方式,基于该导线布置方式推荐海拔高度为0 m时±800 k V与±500 k V导线分别采用6×LGJ-630/45和4×LGJ-720/50型号,而海拔高度超过1 000 m时同极异侧布置方式下的±800 k V导线截面积需增大至6×720/50型号。

Presently there is no well-accepted reference for conductor selection of ±800 kV and ±500 kV mixed-voltage double-circuit DC transmission lines. Thus; to meet the requirements of electromagnetic environment, using the internationally accepted and widely used methods such as analytical method of power lines, empirical formula methods of CISPR and BPA, we researched indexes related to electromagnetic environment （including conductor surface field strength, corona losses, distribution of total electric field and ion flow density at ground level, radio interference, and audible noise） of different wiring combination schemes under four conductor arrangements. Results show audible noise is the decisive factor of choosing conductor types in different altitudes. To compromise technical and economical costs, the arrangement of ±500 kV lines located below is recommended. On this condition it is suggested that in 0 m altitude 6×LGJ-630/45 should be applied to ±800 kV lines and 4×LGJ-720/50 applied to ±500 kV, while above 1 000 m altitude the conductor cross-section of ±800 kV lines should be increased to 6×720/50 when the same pole is on different sides.