Voltage Measurement Method For Transmission Line Based On Electric Field Integral Method

Voltage measurement plays an important role in power measurement,relay protection,overvoltage on-line monitoring,intelligent equipment control,power maintenance and so on.With the accelerated construction of smart grid and the degree of digital,intelligent and automation of power grid is constantly improving.Voltage sensors are required to be digitized,miniaturized and convenient,so it's a trend to research and develop voltage measurement sensors based on new principle.A lot of research has been carried out on non-contact methods of measurementDifficulty in solving voltage and low precision are two outstanding problems exist in the current research of D-dot electric field sensor.In order to solve the problems encountered in the calculation of line voltage,the method that integrate Gauss integral into the design of D-dot electric field sensor measuring system is proposed.Its effectiveness is verified in the experiment.The main work of this paper is as follows:(1)The simulation model of 220 kV high voltage transmission line under three arrangement modes is established in the electromagnetic finite element calculation software Ansoft Maxwell.The softeware is used to obtain the electric field distribution nephogram and the specific values of the electric field intensity at each position directly below the line.The electric field value of the same position under the transmission line is calculated before and after the D-dot field sensor is put into the measured electric field in the electromagnetic finite element calculation software Ansoft Maxwell.Process the two sets of data to obtain the influence of sensors on the measured electric field.(2)An integral operation is performed on the electric field below the transmission line to obtain its voltage.The Gauss and the Gauss Legendre integral algorithm are used respectively to integrate the electric field intensity between the transmission line and the ground.Compare the calculation precision of the two integral method.(3)Make a further improvement on Gauss-Legendre integral algorithm to achieve the precise measurement of line voltage under the condition of least integral node.This is also to obtain the best installation position of the sensor in actual measurement.(4)Build three-phase horizontal arrangement 10 kV test platform,based on the optimal integration method and the sensor placement scheme,carry out verification experiments under the test platform.The results show that the measurement system can achieve good measurement results and verify the algorithm is effective.