特高压直流滤波器滤波标准初步研究

在总结归纳直流谐波源特点、分析以往工程直流滤波器设计判据的基础上,应用对比计算的方法指出±800 kV特高压直流线路上的等效干扰电流Ieq与±500 kV直流的不同特点。计算示例说明直流线路Ieq只是评价直流线路对周围通信干扰的中间指标,实际工程中可以通过增大直流线路与通信线路的间距、减少平行长度、减少导线耦合程度等方法来减少通信干扰。提出±800 kV特高压直流工程直流滤波器滤波标准的确定,应以不影响周围通信线路的通信质量(杂音电动势在规定范围内)为前提,现阶段特高压直流工程仍可按Ieq作为直流滤波的判断依据。

Discussion on DC Filter Performance Criteria for UHVDC Project

Research and determine the DC Filter Performance Criteria for UHVDC Project shall be benefit to the DC Filter or Smoothing Reactor design.The Characteristics of Equivalent Disturbing Current of 800kV UHVDC project have such differentia with that of 500kV project.As a matter of fact,the equivalent disturbing current in the DC circuit is only an indirect index.The effect of the DC transmission lines on the telecommunication lines in the vicinity has relationship with many factors,e.g.the unbalance between the DC transmission lines and the telecommunication lines,the coupling degree between lines,and the conductivity to ground.Enlarge the spacing between the DC line and the telecommunication line or reduce the parallel distance can decrease the interference, rather than reduce the equivalent disturbing current I_(eq) purely.Based on the research,it is point out that the final performance criterion of the DC filters shall be determined on the premise that the flow of harmonic currents do not cause interference with the communication quality of telecommunication lines in the vicinity,i.e.the voice frequency noise induced in the communication circuit by the harmonic current flowing in the HVDC line shall to be kept within such allowable limit.Therefore,it is appropriate to use the equivalent disturbing current I_(eq) =2200mA as the criterion in the preliminary plan of DC filters for UHVDC projects.And the further optimization shall be made at the detail design stage when more information is available,such as ground conductivity,DC lines& telecommunication lines distribution scheme,cost,etc.