Development Of Intelligent Synthetic Protection System For High-Voltage Flameproof Switchgear In Underground Mine

With the development of microprocessor relay protection, many new relay principles andschemes are got more and more attention, and they are also put into practice step by step.However, when the performance of relay protection devices are improved by these newmethods, the higher precision and speed in calculation and more addressing spaceare requiredto these relay protection devices, thus the better hardware of these devices are needed. Aimingat these problems, a new scheme of microprocessor relay protection is proposed in this paper,designs a microprocessor-based protection system, which using double CPUs on the base ofDSP and single chip microcomputer. As the main CPU, DSPcompletes such functions assampling data, processing data and protection. 8051,asthe secondlyCPU, takes responsibilityof conversational function between man andPC, such as dealing withkeyboard, LCD andcommunication. With the excellence of parallel working and cooperating bydividing work, thedual CPU system can realizehigh accuracy of real-time measuring, as well as it can ensure thefastrunningability,selectivity,sensitivityandreliabilityofrelayingprotect.According to the actual situations in underground HV distribution networks, thecharacteristics of the electrical faults occured in the system are theoretically analyzed, andrelevant protective principles and control strategies are proposed on the basis of nationalrelative standards. Especially according tothe present situation that neutral point groundedsystem through arc suppression coil are used in many supper big shaft, the selective leakageprotectivemethodbasedonharmonicdirectionofthezerosequencecurrent aswellasthevalueofzerosequencevoltageispresented.The stability and reliability of hardware is very important to the implementation ofprotection functions. The designed device based on dual CPU structure: DSPand MCS-51, is asynthetical line protection including measurement and control. DSP is used to accelerate dataprocessing, and dual CPU configuration can increase the reliability of the device. Moreover,relayprotection,measurement,control,data-communicationfunctionareinvolvedasawholeunit in this device for fulfilling the needs of the developing of power system and itsautomatization.