输电线路中频融冰频率与热功率均匀度分析

输电线路的覆冰会引发线路过负载、绝缘性能降低、杆塔倒塌、导线舞动等事故,而主流的短路融冰方法都存在着不可克服的缺陷;为此在高频激励新型输电线路融冰方法基础上,针对其在冰层介质损耗角正切值较小时电源频率过高的问题,提出了以牺牲一定融冰热功率均匀度为代价的中频融冰方法。首先基于均匀传输线理论,以长为100 km、电压等级为220 kV输电线路为例,搭建覆冰线路均匀传输线等效电路模型;继而分析沿线电压、电流和功率因数分布规律以及融冰频率与热功率均匀度的相互影响;最后提出输电线路中频融冰最佳电源频率的确定方法。仿真结果验证了所提方法的有效性与实用性。

Analysis of Medium-frequency De-icing Frequency and Thermal Power Uniformity for Transmission Lines

Icing of the transmission lines may cause accidents such as overload,decrease of insulation performance,tower collapse,conductor galloping,and so on.And there are unconquerable defects in some mainstream short-circuit de-icing methods,thus,on the basis of the high-frequency excitation de-icing method and aiming at a problem of overhigh power source frequency as the tangent value of dielectric loss angle of the icing layer is smaller,this paper proposes a kind of medium-frequency de-icing method which is at the expense of sacrificing de-icing thermal power.Based on the uniform transmission line theory,the paper takes one 100 km long 220 kV transmission line as an example and builds an equivalent circuit model of the uniform transmission line for the icing line.Afterwards,it analyzes distribution laws of voltage,current and power factors along the line and the interaction effect between de-icing frequency and thermal power uniformity.Finally it proposes a method for determining the optimal power source frequency for medium-frequency de-icing.The simulation result verifies effectiveness and practicability of the proposed method.