论文和技术资料

Current transformers are used to measure currents in power grid systems. They are characterized by strong interactions between external electrical sources and loads respectively and the magnetic subsystem. Self-heating due to losses has to be considered because of the temperature-dependent material behaviour.

The paper presents a transient 3D FEA transformer model which includes a H(|B|) formulation of the ferromagnetic material behavior based on rational approximation functions, SPICE coupling at the primary and the secondary side, eddy currents computation using a global equation and distributed time-average computation of the losses. This model is bi-directionally coupled to a thermal model. Due to the different time scales of both models, the problem is solved by iteration of each stationary solution of both models.