表面涂层在输电线路导线防晕处理中的应用

Application of Surface Coating in the Anti-corona Measure of the Power Transmission Line Conductor

超/特高压输电线路导线在运输、施工过程中可能会发生碰撞导致导线刮伤或者导线本身就存在缺陷如突出金属物等,形成局部电晕放电源。为此针对人工磨损导线采用喷涂涂层的方式展开电场仿真研究;基于小电晕笼对LGJ400-50导线电晕特性进行试验研究,采用人工划痕和涂污两种方式模拟导线可能存在的缺陷,应用紫外成像仪观察磨损导线喷涂涂料前后电晕放电过程的变化。绞线电场仿真结果表明:划痕和凸起两种典型的导线表面缺陷时会严重畸变导线周围电场,使表面最大场强分别达到原来的1.29和2.19倍,而采用喷涂涂层的方法可以有效的降低绞线表面最大电场强度达51%和62.4%。试验结果表明:涂覆RTV涂料后起晕电压升高约21.9%和39.2%,相同的电压下导线电晕放电强度明显减弱,涂层在导线防晕处理中起到了较好的效果。

During the transportation and installation of EHV/UHV power transmission line conductors, the impact induced stretches on the conductors＇ surfaces and the probable protrusions on the conductors may become corona discharge sources when the conductors are operating. Hence, we studied the effect of artificial coating on the flawed conductors through numerical simulation. We also tested the corona characteristics of coated LGJ400-50 conductors, which carried typical flaws simulated by artificial scratch and brushing dirt, using a small corona cage. In the tests, the corona discharges before and after spraying the coating on the conductor were recorded using a UV detector. The simulation indicates that stretch and protrusion will greatly distort the surface electric field, of which the maximum intensity is in- creased by up to 1.29 and 2.12 times of the original value, respectively. Yet the coating could reduce this increased maximum electric field intensity by 51% and 62.4%. The test results show that the corona onset voltage is reduced by 21.9% and 39.2% for conductors with scratch and protrusion, respectively, while the discharge intensity is also weakened under the same voltage, so the coating has good corona proof performances for conductors.