基于过流延时整定表的微机反时限算法研究

Microprocessor-based inverse time algorithm study based on overcurrent delay setting table

为了将过流保护用的过流延时整定表变换为微机反时限算法,用国际通用过流反时限特性方程对过流延时整定表进行MATLAB最小二乘拟合,发现对应过流延时整定表的一组反时限特性方程在整定参数上存在近似一致性,从而提出积分限比率的概念,构造出一种微机反时限新的实现方法。该算法可以把有级延时整定方式转变为无级延时整定方式,实现简单,占用内存小。MATLAB仿真表明,延时控制精度对于非常反时限整定表不低于3%,对于一般反时限不低于6%,适用于微机保护装置的各种反时限过流保护。矿用隔爆型高压配电装置过流实验表明,这种微机反时限新实现方法达到工程应用要求。

In order to convert the overcurrent delay setting tables of overcurrent protection to microprocessor-based inverse time algorithm, the overcurrent delay setting tables are fitted using MATLAB least square with international common type overcurrent inverse time characteristic equations. It is found that a group of inverse time characteristic equations corresponding the overcurrent delay setting tables has approximate consistency in the setting parameters. Therefore a concept of integral limit rate is proposed and a new microprocessor-based inverse time algorithm is developed. This algorithm can transform graded delay setting into no-graded delay setting, which is simple to implement and occupies less memory. MATLAB emulations show that delay control precision is less than 3% for the special inverse time setting table and less than 6% for the normal inverse time setting table. The algorithm is suitable for all kinds of inverse time overcurrent protection in microprocessor protection mechanism. The overcurrent test for mine flame-proof high voltage vacuum switch cabinets proves that this algorithm meets engineering application standards.