沙尘粒径效应对分裂导线电晕特性的影响

Influence of Sand Particle Size Effect on Corona Discharge Characteristics of Bundle Conductors

我国西北750 k V输电线路经过地区沙尘天气频发,沙尘天气的存在可能会对输电线路导线电晕特性产生影响。为此针对沙尘的粒径对导线的电晕特性影响展开仿真计算和试验研究,采用偏心偶极子法结合模拟电荷法对存在沙尘颗粒时导线周围空间电场分布进行计算,并在人工模拟沙尘条件下展开了导线电晕放电强度和电晕损失测量试验。研究结果表明:沙尘颗粒会使导线周围电场产生严重畸变,和导线距离相同时,大颗粒的沙粒对导线周围的空间电场影响更大,在沙粒接近导线时,沙尘颗粒表面场强约增加为无沙尘条件下原场强的2倍,沙粒-导线之间的平均场强可较无沙尘条件下最大增加11.8%;沙尘条件下导线电晕放电强度较无风沙时明显增强,且沙尘粒径越大则对电晕放电强度和电晕损失的影响越大,在该试验条件下,LGJ400-50导线在设计场强范围内无沙尘条件下的电晕损失最大不超过2 W/m,而在沙尘条件下的电晕损失最大可达60.76 W/m。仿真结果和试验结果都说明沙尘条件会对导线电晕放电产生影响,且粒径大的沙尘对电晕放电的影响程度更大。

Sandy and dusty weather often occurs in Northwestem China where 750 kV power transmission line passes by, and the sand particles may affect the corona characteristics of power transmission line conductor. Consequently, we cal- culated and experimentally researched the influence of particle size on corona characteristics. The displaced dipole method and charge simulation method were used together to calculate the electric field strength of the conductor with the consideration of sand particles, and corona discharge characteristic test was done in simulated sandy condition. The re- search result shows that sand particles will distort the electric field near the conductor. When the distance is fixed, larger sand particles will have more serious effect on the electric field strength. When particle is in the vicinity of the conductor, the electric field strength on the surface of the particle is about 2 times that the original electric field strength in the ab- sence of particles. The average electric field strength between the conductor and the particle can increase by 11.8% at most compared with that in the absence of particles. Sandy condition apparently increases the corona discharge intensity and corona loss of the conductor, and with the increase of sand particle size, corona discharge becomes more serious and corona loss increases. Corona loss of LGJ400-50 will not exceed 2 W/m in the absence of sand, while corona loss will reach 60.76 W/m in the sandy condition. Both the test result and simulation result prove that sandy condition will influ- ence corona discharge of the conductor, and particles with larger sizes will have more serious influences.