同步发电机Td′和Td″近似算式分析

Analysis of the Approximate Calculation for Td′ and Td″ of Synchronous Generator

研究对比同步发电机直轴时间常数复杂近似算式和由其导出的简易近似算式的误差。分析简易近似算式误差小于复杂近似算式误差的条件,并以45台同步发电机实际数据对其进行验证,分析近似算式传统推演方法存在的问题,研究推演简易近似算式的合理前提和方法。认为简易近似算式误差小于复杂近似算式误差的条件为σ′d>0.5,绝大多数同步发电机满足这一条件。复杂近似算式推演采用的假设条件不符合同步发电机实际,建议废弃复杂近似算式,并给出了一种直接由直轴时间常数准确算式推演简易近似算式的简明方法。

In this paper, errors of the complicated approximate equations and their simplified equations for daxis transient and sub-transient time constant of synchronous generator are studied and contrasted. The condition that the simple ones＇ error is smaller than the complicated ones＇ is analyzed and validated by the factual data of 45 synchronous generators. As a result, most generators meet the condition. The problems of conventional deducing method of approximate equations are introduced, and then the reasonable precondition and method for deducing the simple equations are investigated. The complicated approximate equations are not suggested to use as its assumed condition doesn＇t coincide with the actual situation of generator. Finally, a method for directly deducing from the precise equations to simple approximate equations is presented.