engleski

Numerical Calculations of Three-Phase Transformer's Transients

A three-phase, two-winding transformer&#8217 ; s model is presented in the paper. The triplex core configuration is assumed in the transformer&#8217 ; s model. Nonlinear magnetizing curves are piecewise linearized. Input winding capacitances can be lumped to the transformer&#8217 ; s terminals. A stiff differential system in state space, describing transformer&#8217 ; s transient behavior, is solved by the L-stable backward differentiation formulas numerical rule. BDF compared to trapezoidal rule shows better stability properties. A computer program is developed for generation of variable state waveforms. The developed program is suitable for simulations of low-frequency three-phase transformer transients such as inrush currents and ferroresonance. Results of the developed program are compared to MATLAB/Power System Blockset results.

Inrush currents; ferroresonance; modeling; state space methods; stiff differential equations; transformers; transient analysis

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