Design And Research On Control System Of Three-phase Synthetic Test

The synthetic test method is an important means to check whether the high-voltage circuit breaker has reliable breaking capacity.In order to ensure its equivalence with the direct test,it is necessary to accurately put the voltage circuit and the extended arc circuit into operation at a certain set time before the current zero crossing point,and generate the arc burning time in the circuit breaker that meets the test requirements,which puts forward higher requirements for the control method of the synthetic test.In addition,with the development of three-phase common box circuit breaker,its breaking performance needs to be tested in the three-phase circuit,which makes its control more complex and more difficult,and it is very necessary to study the control system of three-phase synthesis test.Therefore,a three-phase synthesis test control system is designed based on the basic principle of synthesis test.In this paper,the working process and circuit structure of the synthesis test are introduced in detail,and the control tasks of the three-phase synthesis test are defined by analyzing the control requirements of the voltage circuit,the arc extension circuit and the arcing time of the three-phase synthesis test,and the corresponding control strategies are analyzed and studied by establishing the model and simulating.According to the nature of the synthetic test control signal,the three-phase synthetic test control system is divided into three parts,including the upper computer,timing control unit and synchronous control unit.To realize the overall control of the three-phase synthesis test,the upper computer operation software of the synthesis test is designed by LabVIEW.The operator can set the test parameters on the software page and control the operation of the three-phase synthesis test.According to the requirements of multi-channel timing control,the timing control unit with FPGA as the core is designed.Through the communication with the upper computer,the corresponding timing control signal can be generated according to the test parameters set by the user.In order to verify the correctness of the design,the simulation and analysis is carried out.And the simulation results show that the timing control unit can generate multi-channel timing control pulses and has high control accuracy.According to the control requirements of voltage loop and arc extension loop,a synchronous control unit based on DSP is designed.The recursive least square algorithm is used to predict the current zero point,and the corresponding improvement is made according to the control accuracy requirements of the synthesis test.Finally,the synchronous control unit is verified by experiments,and the results show that the synchronous control unit based on DSP can accurately predict the zero crossing time of the short-circuit current,and accurately generate the trigger pulse at the set time before the zero point,which meets the control requirements of the synthesis test.