基于自定义模型的变压器纵差动保护PSCAD仿真

为了减少变压器的继电保护设计、整定计算存在的误差,提出一种根据内部漏抗参数等值计算与短路阻抗实际参数测定相结合的方法,利用曲线拟合技术,得出变压器在不同故障条件下的精确等值短路阻抗参数。在此基础上,采用FORTRAN语言接口技术,在PSCAD/EMTDC中,结合实际数字式变压器保护装置建立了主保护及后备保护的精确短路阻抗自定义模型,并利用等值系统模型对变压器线圈内部不同位置的对地短路、匝间短路、相间短路分别进行了仿真计算。结果表明,采用新型的拟合方法及自定义元件能准确地模拟并分析变压器内部故障及继电保护装置的动作行为,为继电保护的原理设计及实际应用提供科学依据。

PSCAD simulation of transformer longitudinal differential protection based on custom model

In order to reduce the error of the design of relay protection, setting calculation of transformer, a method is proposed based on the combination of internal leakage reactance parameters calculation and short-circuit impedance parameters determination. By using curve fitting technique, this method obtains the exact equivalent short circuit impedance parameters of the transformer in different fault conditions. On this basis, it establishes the custom model of the short-circuit impedance of primary protection and backup protection combining the real digital transformer protection device in the PSCAD/EMTDC by using FORTRAN language interface technology. Besides, using the equivalent system model, the short circuit to ground short circuit, inter-turn short circuit, phase to phase short circuit within the different positions of the transformer coil are simulated and calculated. The results show that, using the curve fitting method model and custom element can accurately simulate and analyze the internal fault of transformer and relay protection action, which provides a scientific basis for the design of relay protection principle and application.