Design Of Relay Protection System For Medium Voltage Intelligent On Line Monitoring Cabinet

With the country’s demand for new energy sources,and the introduction of a variety of distributed generation incentive policy makes the new energy power generation industry by leaps and bounds.In the development at the same time,the stability and reliability of the power generation system can not be ignored.Switch cabinet and protection device as the core protection components in the power system plays an important role in the whole system,real-time monitoring of the running state of the line,when the fault occurs in a timely manner to protect the action.This paper expounds in detail the integrated protection device in switch cabinet in order to reduce the cost and volume of the purpose,selected the commonly used frequency protection and voltage protection device body two protection content protection target,design a protection device integrated in the switch cabinet,the voltage and frequency of the fixed value setting and real-time monitoring of the switch cabinet state of voltage and frequency field voltage and frequency of abnormal protection,low voltage protection device can,on line protection,overvoltage protection,low frequency protection.The hardware design using DSP as the processor architecture,using Blackfin series BF533 processor of ADI company as the control core,designed the main CPU board,switch signal board,AC sampling board and bus board,each function card inserted in the bus card,exchanging data through the data bus on the bus board.Some are equipped with switch input and output coupler isolation measures,improve system reliability.In the software design,the standard C language is used to develop.The protective function of the software algorithm uses the algorithm library and component instantiation algorithm written in a way,protection logic will have common classified operations,according to the generation of protection logic element specific configuration parameters,for sequentially scanning each protection element in the protection task,so as to realize the protection of all the functional requirements within the device.And to produce the prototype of integrated flow testing,calibration of the acquisition function using standard AC source,combined with PC debugging software shows the amount of data exchange information collected by the current device,the protection function of event information,the current input data and a data state.And through the PC debugging software to achieve the remote control of the device and set the value of the protection settings and changes.At the end of this device debugging function of protection system,the protection device to test device for protecting logic function action value and time value to verify the data transmission device is stable,reliable action,position change information can be recorded and uploaded.The integration of the device into the switch cabinet has a good effect on the intelligent switch cabinet,and it also has important social significance to reduce the construction cost of the substation.