Research On Non-contact Measurement Of Electric Field In Electrical Switchgear Busbar

During the process of operation and maintenance of the power system,more and more electrocution accidents occur in the electrical switchgear,which not only poses a serious threat to the life safety of the power workers,but also restricts the vigorous development of the power industry in China.Therefore,it is of great significance to study the non-contact electric field measurement of the three-phase busbars of the electrical switchgear.In this paper,the busbar electric field of the electrical switchgear is studied by means of modeling,simulation and experiment.The general law of the busbar electric field distribution is discussed,and the purpose of improving the personal safety of the operator during the repair of the electrical switchgear cabinet is realized.First,the deficiencies of existing measurement devices are discussed.It is determined that the potential and field strength are taken as the objects of measurement,and through the theory of electrostatic field,the finite element method is used as the analysis method to study the busbar potential and field intensity distribution of the electrical switchgear.Secondly,the model of KYN28-12 armor type switchgear busbar is established.The KYN28-12 armored switchgear and three-phase busbars were physically measured,and the three-phase busbar model of the 10 kV switchgear was modeled and conditions were assumed for the model.COMSOL Multiphysics software was used to model the high voltage switchgear and three-phase busbars to simulate the actual operation of the 10 kV switchgear,and the distribution of potentials and field strengths was obtained.Analyzing the change of potential and field strength of the three-phase busbar model of high-voltage switchgear under different initial conditions,and introducing the change of any change factor,it will only affect the potential and field around the busbar when the busbar structure and the cabinet are determined.Strong numerical values do not affect the conclusion of their nature.Thirdly,the non-contact measurement system of electrical switchgear is established.Based on the capacitive sensor,the measurement model of non-contact measurement system is established.The theoretical analysis of the capacitive sensor yields the relationship between the bus voltage and the measured potential and the field strength is concluded.At the same time,the signal processing circuit is completed and the STM32F103ZET6 is used as the main control chip of the design of hardware and software for non-contact measurement systems.Finally,the busbar electric field of the 380 V distribution cabinet is measured.Using the designed non-contact measurement system to measure the electric field around the busbar of the 380 V distribution cabinet,the finite element simulation of the busbars of the 380 V distribution cabinet is carried out according to the 10 kV switchgear busbar modeling method.The results show that the design of non-contact measurement system is similar to the simulation result,and it can realize whether the switchgear busbar is electrified and displays the alarm function,which verifies the practicality of the non-contact measurement system.