基于耐热量降低原理的配电系统微机反时限过流保护

 提出航空及民用配电系统耐热量降低原理，对国际电工委员会(IEC)标准规定的反时限特性曲线，研究用电设备过流保护跳闸条件、过流损坏的相对临界耐热量和电流热功率，设计一种快速高精度的反时限过流保护方法，并仿真分析其实现过程。统一定义10倍过流延时时间为时间整定值，使反时限函数具有统一明确的量化参数，并推导出相应的反时限特性方程，使参数更容易整定。该方法克服了传统反时限过流保护不能准确反映电流快速变化时真实故障状态的缺点。根据耐热量降低原理推导一种简单实用的反时限动态特性测试方法,静态和动态实验结果表明该方法快速性好和准确性高，为航空供电系统机载用电设备及民用设备反时限保护提供了实现方案。

Inverse-time Overcurrent Protection Based on the Theory of Decreasing Value of Thermal Resistance in Electric Power Distribution System

The theory of decreasing value of thermal resistance is proposed for the aircraft and civil electrical power distribution systems protections. Trip conditions are studied based on the International Electrotechnical Commission (IEC) inverse-time standard characteristic curve. The thermal resistance and thermal power are calculated. A precise inverse-time protection is designed, and its process of implementation is analyzed with simulation. This paper defines the time delay under 10 times over-current as the time dial and therefore gets the other three inverse-time functions which have uniform and unambiguous quantified parameters, so the parameters dial is set easily. This method overcomes the obstacle that the traditional inverse-time over-current protection can’t reflect the real fault state under fast changing fault current .An easy and practical inverse-time characteristic test method is developed, and both static and dynamic characteristic experimental results are presented in the end. Testing results indicate that this method has fast characteristic and high precision for aircraft and civil electrical equipment protection.