State Parameter Monitoring Method Of Vacuum Circuit Breaker

Vacuum circuit breaker is important switching equipment in the power system, the safetyand stable operation of the power system is decided by it. Therefore, strengthening the testing onthe status parameters of vacuum circuit breaker is very important. The key of state parametersfactors on the influence of the circuit breaker is analyzed and then the average speed of dynamiccontact when it is switching for the state parameter is selected. Modern sensor technology andsignal acquisition technology is used in the research of the circuit breaker operatingcharacteristic as the state parameter detection method.First of all, the vacuum circuit breaker state parameter is introduced, it is concluded that theinfluence on the normal operation of circuit breaker of the mechanical characteristic parametersand the electrical parameter. Circuit breaker failure is mostly caused by the mechanical failure.The dynamic contact points switching average speed can be a very good characterization ofoperating mechanism failure, so choose the average speed of dynamic contact in the process ofvacuum circuit breaker when it is switching as the measuring signal of state parameter detection.Secondly, in view of the deficiency of several speed sensors, the process of the circuitbreaker points switching and the principle of changing machinery to electric, the measurement ofcircuit breaker speed is changed to the voltage parameter measurement. The method is realizedby fixing permanent magnet on the insulation rod mounted contacted with the circuit breakerdynamic contact, much coil is tied around it. When the permanent magnet moved, according tothe electromagnetic induction principle, the coil voltage is induced. Circuit breaker dynamiccontact movement speed can be calculated through the sensor induced voltage measurement.This part mainly completed the sensor model establishment and ANSOFT transient simulationcalculation of the magnetic field. After completing the model, the permanent magnet material ischosen and the detailed dimension about coil structure is design while winding width calculation,etc. In ANSOFT3D DESIGN,3D model of the sensor was set up. Giving different speed to thepermanent magnet in the model, coil internal induction voltage waveform under different speed was get respectively. Gathering much sets of data, the relationship between the induction voltageand the average velocity of permanent magnet movement is calculated, this provided theoreticalbasis for the real testing on the speed of circuit breaker.Finally, the signal data acquisition is completed. DSP F2812is choose as the processing chipof the signal data acquisition, then it is combined with the A/D conversion chip in it and thedesign of DSP minimum system as data acquisition unit is completed. The softwareprogramming included the DSP main program design, A/D interrupt subroutine design and CANcommunication subroutine design, etc. The data collection and calculation process of the vacuumcircuit breaker dynamic contact points closing speed signal is realized by the design of softwareand hardware.