基于S函数的数字式变压器差动保护仿真

Digital transformer protection simulation based on S-function

利用Matlab中的Simulink及SPS(SimPowerSystem)工具箱建立变压器仿真模型,利用S函数(S-Function)进行差动保护算法编程,以实现差动保护功能,建立了双绕组变压器差动保护的仿真模型,其中包括了比率制动与二次谐波制动等模型。在仿真模型中,该差动保护功能可以反应变压器差动保护区内的不同类型的故障,并能正确动作于跳闸;当空载投入变压器时,该差动保护又能够根据励磁涌流可靠闭锁。仿真结果表明,S函数所编写的数字式差动保护的S函数仿真程序是正确的。还对部分S函数(S-Function)编写的差动保护算法语句进行了说明。

Using Simulink and SPS（ simpowersystem ） toolbox and S-Function in MATLAB software, this paper establishes a three-phase saturable transformer and its differential protection simulation model. Simulink and SPS（ simpowersystem ） provide a graphical user interface （GUI） for building a transformer models as block diagrams. The transformer differential protection model, which were created using S-Functions, contains a transformer ratio brake and twice harmonic brake differential function. This paper uses the M-file to program the differential protection S-function. The transformer and its differential protection simulation model can operate or brake correctly according to varietals internal faults or external faults such as single faults, two phase faults, three phase faults, two phase grounding faults etc. The differential protection model also can be barked through analyzing the twice harmonic in the inrush current during energization of a three-phase saturable transformer. The simulation results indicate that transformer digital protection S-Function programs are correct. This paper also shows some differential protection S-Function program and explanation.