动态过载长延时保护数学模型

摘要

Overload protection models suitable for different objects can ensure validity of overload protection. This paper presents an analysis of a mathematical model of overload protection with long time delay characteristics, which is commonly used in intelligent circuit-breaker. It establishes a dynamic overload protection model by taking temperature increase as a variable based on the heat balance differential equation, and gives a new protection criterion. The paper discusses the relation between errors in the overload long time delay measurements and errors in electrical current measurements. Compared with the common inverse time characteristics, this model better conforms to the load actual operating rule.%研究分别适用于不同对象的过载保护模型，可以提高过载保护的有效性。对目前智能断路器常用的过载长延时保护特性的数学模型进行了分析，以温升为变量，采用求解热平衡方程的方法，建立了动态过载保护数学模型，得出新的过载保护判据，并讨论了过载长延时测量相对误差与电流相对误差的关系。此保护模型与常用反时限保护特性相比较，更符合负载的实际运行规律。