Protection System Of Resonant Cells In CSNS/RCS Magnet Excitation Power Supply

The accelerator of CSNS is a rapid cycling synchrotron(RCS),in which the magnet excitation power supply system adopts the structure of a resonant network.In the RCS of CSNS the resonant network consists of the switching power supply,magnets,the resonant reactors,and the resonant capacitors.The rated current of excitation network element is mainly reactive power and with little active power.If the capacitor or reactor fails,a large induced voltage will be generated,which will cause damage to the equipment.In order to monitor the working of the resonant network element,a protection system is designed to keep a watch on each part of the cells and realize fault diagnosis and troubleshooting.This paper presents the research of the protection method of the resonance network and the realization of the protection device.Analog signals are converted to digital signals for processing with FPGA.If any parameter does not meet the rated value,this device sends a protection signal to stop the power supply.Through FFT analysis and calculation,the effective value and the loss angle of capacitance are obtained and displayed on the touch screen.The ADC processing and protection function based on FPGA are the most important part of the device.The hardware of the device also includes relay input/output function as a PLC,in order to build a complete protection system.A results show that this device has passed the performance test and achieved the expectation.