We measured transient recovery voltage (TRV) in a 1500 MVA-525 kV/276 kV/63 kV transformer of the three-phase-in-one-tank type. We proved that TRV can be measured by interrupting the current generated by discharging a capacitor of low voltage through the transformer. The current was interrupted at its zero point by a diode at a low voltage. To calculate TRV via a computation, we developed a transformer equivalent model composed of a L-C multi-mesh circuit. The TRV waveform computed using the transformer equivalent model we developed agreed well with the measured TRV waveform.