A new optical voltage sensor for linear measurement

An OVT based on Mach-Zehnder interferometer is proposed in this paper, which helps to convert the electro-optic phase delay into the displacement of the interference fringe. And then, the voltage applied to the electro-optic crystal is obtained by positioning the displacement of the fringe, and the effectiveness of this method is verified by experiments. The new OVT meets the requirements of 0.5% accuracy class. And it has advantages of direct linear measurement, independent of light intensity and no limit by half wave voltage of crystal in measurement range. Moreover the new OVT is simple and easy to be built up.

I. Introduction

Traditional electromagnetic voltage sensors have many disadvantages, such as poor security, poor ability to resist electromagnetic interference, large size, high cost and so on, making it difficult to meet the requirements of the modern power grid [1]–[4]. Optical voltage transducers(OVT) on the other hand have many advantages, for example no electromagnetic interference, low cost, small size, light weight, wide frequency band and so on. And they have technical and principle advantages compared with traditional electromagnetic voltage transformers [5]–[9].