This paper presents a new procedure to characterize an admittance matrix over a wide frequency band, for the purpose of black-box modeling of power transformers. Unlike previous approaches, our setup is based on a commercial sweep frequency response analysis (sFRA) measurement instrument which is light-weight and considerably less expensive than dedicated high precision laboratory equipment. The use of 50 Ω termination resistors allows measuring the terminal admittance matrix without a need for correcting for the measurement cables. The measured admittance matrix is next subjected to rational modeling using Vector Fitting and passivity enforcement. When applied to a 300 kVA distribution transformer, the resulting model accurately reproduces measured time domain waveforms.
- High frequency transformer models
- Vector Fitting
- EMT program
- Frequency domain measurements
- Time domain measurements
- Model creation and validation