Composite high voltage source for instrument voltage transformer frequency response evaluation up to 10 kHz

The measurement of high voltage, high frequency, harmonic distortion has gained the attention of numerous researchers recently. The increases in the number of harmonic emission sources due to the extensive use of power electronic devices has resulted in increased levels of harmonic voltages and currents in the power system. While measurement of harmonic voltages in LV networks is well established, MV distribution and HV transmission networks often require dedicated instrument voltage transformers (IVTs) in the measurement chain. The calibration and verification of the measurement accuracy of IVTs is generally performed under non-distorted sinusoidal input voltage conditions. The frequency dependent behaviour of IVTs is often unknown or not been properly verified. Hence, a HV calibration system, which allows calibration under distorted sinusoidal waveform conditions that represent actual power system voltage characteristics, is required. This paper presents the details of a composite voltage source that can generate a practical waveform with a HV fundamental component and superimposed voltage harmonics up to 10 kHz.