New Sensor for Medium- and High-Voltage Measurement

Andrzej Wetula,Mrunal Parekh,Andrzej Bień

doi:10.3390/en14154654

Andrzej Wetula, Mrunal Parekh + Show 1 more

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https://doi.org/10.3390/en14154654

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Abstract

Measurements of medium and high voltages in a power grid are normally performed with large and bulky voltage transformers or capacitive dividers. Besides installation problems, these devices operate in a relatively narrow frequency band, which limits their usability in modern systems that are saturated with power electronic devices. A sensor that can be installed directly on a wire and can operate without a galvanic connection to the ground may be used as an alternative voltage measurement device. This type of voltage sensor can complement current sensors installed on a wire, forming a complete power acquisition system. This paper presents such a sensor. Our sensor is built using two dielectric elements with different permeability coefficients. A finite element method simulation is used to estimate the parameters of a constructed sensor. Besides simulations, a laboratory model of a sensor was built and tested in a medium-voltage substation. Our results provide a proof of concept for the presented sensor. Some errors in voltage reconstruction have been traced to an oversimplified data acquisition and transmission system, which has to be improved during the further development of the sensor.

Highlights

Voltage measurements in medium- and high-voltage power grids require a device that lowers the voltage to a level acceptable for measurement systems and safe for their operators
The experiment consisted of recording both sensor input and output voltages for various values of input voltage
The proposed sensor consisted of two dielectric elements that were made from different materials, which were used to obtain different dielectric constants

Summary

Introduction

Voltage measurements in medium- and high-voltage power grids require a device that lowers the voltage to a level acceptable for measurement systems and safe for their operators This task is performed using either voltage transformers (VTs) or cascaded capacitive voltage dividers (CCVDs). These devices have some disadvantages, especially when used in a power quality (PQ) measurement scenarios or a smart grid operation. They are large and heavy, limiting the number of voltage measurement locations. Another disadvantage of VTs and CCVDs is their poor frequency response. This issue was observed as early as in the late 1970s [1], and the development of correction techniques followed [2]

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