Performance Analysis And Optimization Of Under-voltage Release

Low-voltage circuit breakers are widely used in power equipment,when the distribution system failure,the circuit breaker can quickly cut off the circuit.With the development of technology,low-voltage circuit breakers are moving toward the miniaturization,low power consumption,intelligent direction.Under-voltage release is a very important part of the circuit breaker,and only its reliable work can ensure that the circuit breaker breaks in the event of loss of under voltage,which can play a protective role.In this paper,the under-voltage release of QTW45-1600 model is taken as the research object.The under voltage release is mainly composed of circuit board and electromagnet mechanism.In this paper,the electromagnetic analysis,thermal analysis and optimization of the tripping device are carried out by experiment and finite element simulation.First,the working principle of the QTW45-1600 model is studied by experiments.The voltage and current waveforms of the under voltage release were tested by the regulator and the oscilloscope.The spring force was measured by spring tension and compression testing machine,and the stiffness coefficient of the spring was calculated.The electromagnetic suction of the trip unit was measured by suction test instrument.Secondly,the 3D model was established by ANSOFT.The static and dynamic processes of the electromagnet are simulated and analyzed,and the suction force of the moving core in the electromagnetic system was obtained by adding the constraint condition,the moving stroke,the excitation and the meshing grid.The relationship between the electromagnet suction,displacement and time and the magnetic induction intensity distribution was obtained.Then the simulation results were compared with the experimental results,and the feasibility of the simulation was verified.With the electromagnetic suction of the dynamic core in the retention phase as the goal,the influence of different parameters on the electromagnetic suction was studied,the optimal size was given,and the performance of the electromagnet was improved.According to the thermodynamics theory,Maxwell and ANSYS Workbench were used to simulate the transient electromagnetic thermal simulation of the under voltage release.Maxwell was used to calculate the loss value of the electromagnet during the retention phase.The loss value was introduced into the Workbench as a heat source.Byadding material properties,dividing the grid,setting up the simulation time,simulating the temperature field of the electromagnet,the temperature distribution of the under-voltage release was obtained.This study provides some reference for the optimization and improvement of under voltage release,which is of great significance to improve its performance.