Coherent Demodulation of the Output Signal of Optical Voltage Transformer

This work addresses a technique of coherent demodulation based on the synchronous detection of peak and valley values of the photocurrent produced by a photodiode connected through an optical fiber to the output of a recover interferometer, which is part of an Optical Voltage Transformer (OVT). The adopted OVT topology allows the recover interferometer output signal to hold the relevant information about the ac high-voltage applied to a sensor interferometer. A series of tests was conducted to estimate the OVT performance, in a laboratory environment, measuring ac high-voltages up to 20kV. The good results obtained are very promising, and encourages to pursue this research aiming to develop an OVT prototype suitable for application in electrical distribution and transmission substations.