Hydro Generator Damper Bar Current Measurement at Wanapum Dam

This paper details the rotor pole damper bar current measurement conducted on a 109-MVA hydro generator at Wanapum Dam on the Columbia River (USA). The measurements were done using custom sensors and instrumentation in order to study the rotor pole face phenomena. We recorded the five damper bar current waveforms of one pole in the hydro generator in steady state and during severe transient conditions including three- and two-phase sudden short circuit. We also installed search coils on the pole face and temperature sensors on the damper bars. The current waveforms are presented for many steady-state and transient phenomena. The steady-state results are compared with the theoric space and time harmonics order and simulation results. The damper bar current sensor was capable of measuring up to 12.5 kA, which proved useful for the sudden short-circuit tests as shown in this paper.

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