Research On Fault Detecting And Diagnosis Techniques Of Excitation Power Circuit

Generator excitation system is the important part of synchronous generator and it plays an important role for the generator and the whole power system’s performance-security,stability and reliability.Besides,the excitation power rectifier cabinet is an integral part of the generator excitation system.Thus,it is necessary to make a research for monitoring and diagnosising the excitation power ark’ malfunction.What’s more it is beneficial to discovery and handle the problem as soon as the trouble happens.As a result the downtime or maintenance time will be shorten and the losses of the equipments’ sudden breakdown or stop running will be reduced,the coefficient of safe operation and the reliability will be improved,thus making good economic benefits.On the basis of kinds of home and abroad exciting power cabinet fault monitoring and diagnosis system, a solution that can monitor and diagnosis the falut of the system was proposed and a new type of excitation power cabinet which can monitor and diagnosis the system was produced.First of all,the paper is based on Multisim simulation software to build the modle of excitation power unit which can simulation the normal and kinds of fault states.The FFT analysis method will be used to make a research of voltage waveform data for the states which have presented above.Thus making full use of the analysised data to calculate the corresponding fault monitoring and diagnosis criterion. ST’s STM32F407 series 32-bit microcontroller was selected as the main control and diagnosis unit. The main controller module circuit,clocking circuit and reset circuit,interface debugging circuit,data acquisition circuit,fault data storage circuit and the communication circuit formed the hardware circuit.Among them,the data acquisition circuit includes sampling circuit and three-phase alternating current excitation voltage circuit and others;the communication interface circuit includes a RS485 and two CAN communication interface circuits and so on.Secondly,about the software design, on the basis of the hardware circuit and to meet the system’s function, a programming idea was proposed which is modular,structured to accomplish software programming.It includes the data acquisition program,fault monitoring and diagnosis, the system and PC communication program and the PC man-machine interactive interface which is based on LabVIEW program, etc.Finally,in view of the excitation power ark’s fault monitoring and diagnosis system’s software and hardware,then make a integrated debug and test. In the experiment, making the excitation power unit run in normal and various kinds of fault conditions was needed and the results show that the system can judge the fault types effectively and fault unit has met fault monitoring and diagnosis and the system operation stability which has reached our expected purpose.