有限长交流输电线路电晕的无线电干扰

Radio interference caused by corona on finite-length AC transmission line

电力系统运行过程中产生的无线电干扰会影响周边环境和设备运行,进而影响电力行业的进一步发展.因此有必要对线路无线电干扰水平进行计算研究.为此提出了一种以变电站出线端为代表的有限长交流输电线路电晕的无线电干扰计算方法.根据输电线路的空间排列、材料参数,采用激发函数法,得出当三相线路发生均匀电晕时产生的电晕电流.然后利用相模变换和行波在变电站入口处发生反射的原理,建立了体现电晕电流在有限长导线端部反射特性的传播模型,计算出电晕电流在空间任意点产生的电场强度,进而得到无线电干扰值.以变电站出线端的有限长输电线路模型为例,对单回和双回线路的无线电干扰进行了计算,并研究了不同空间位置无线电干扰值的规律.实地测量值验证了计算方法的准确性,对后续研究和工程实践提供了参考和指导.

Radio interference caused during the operation of the power system would affect the surrounding environment,which links closely with the health of living creatures including human beings. It also cause problems in equipment operation, which in turn affect the further development of the power industry. All these issues make it necessary to implement a deep research into the calculation of radio interference. A method to calculate the value of radio interference caused by finite-length AC transmission lines is pro- posed. Based on the excitation function, when corona occurs evenly in the three-phase lines, corona cur- rents are calculated according to the spatial arrangement and material parameters of the transmission lines. By considering phase-mode transformation and how corona currents transmit in the case of reflection and refraction,a transmission model which reflects the reflection characteristics of corona currents in finite- length transmission lines is established. And then the electric intensity caused by corona currents and the value of radio interference are obtained. Taking the model of finite-length AC transmission lines of the substation outlet side for example, the radio interferences caused by single-circuit transmission lines and double-circuit transmission lines are calculated. Besides, the relationship between radio interference and spatial location is also studied. By adopting rational material parameters and setting the structures and spatial arrangement legitimately, the radio interference can be limited into a reasonable range. Field measurements have proved the accuracy of the calculating method, which would provide useful references and guidance to further researches and engineering practices.