Development Of Protection System In High-voltage Switchgear For Mining Flameproof Mobile Substation

The content of this thesis plays an important role in the project “TheDevelopment of High-voltage and Low-voltage Feeding Switchgear for MiningFlameproof Mobile Substation”(No: JSYJ-JSKF-2014-0050), sponsored byShanxi Jincheng Anthracite Coal Mining Group Co. Ltd.. The work is proposedon the issue of mining high-voltage feeding switchgear such as low measuringaccuracy, antiquated sampling algorithm, poor anti-jamming performance,difficulty in setting of parameter, great frequent tripping faults and unitaryfunction. With the rapid development of coal industry in China, newrequirements for reliability, security and continuity of mine power supplysystem are proposed, in the meantime, high demands of protection system inhigh-voltage feeding switchgear of mining flameproof mobile substation whichensures safe operation of system are put forward. Therefore, it is significant forraising the reliability and safety of power supply system to develop a set ofintegrating multiple protection, communication, measurement and controlfunction protection system in high-voltage switchgear for mining flameproofmobile substation.After analysing failure cause, failure type and protection arithmetic,protection system was developed based on double CPU structure ofTMS320F28335and C8051F020in high-voltage switchgear for miningflameproof mobile substation. The protection system can not only realizereal-time measurement, analysis, judgment and processing of high voltagepower grid data, but also can communicate with many machine, realize theresource sharing, remote monitoring and other functions. And solid foundation is provided for digital safety production of coal mine. The main contents of thisthesis are as follows:After literature reviewing and site investigation, failure cause, failure typeof mining high-voltage electric network is analysed conscientiously. A newscheme for preventing override trip is proposed based on optical fiber lockingcontrol. Multi machine communication through optical fiber which is applied inquick break protection, can realize the selectivity of the short circuit protectionaction.Considering the environment and structure of power supply system andmaking sure of the safety of power supply system, the system is designed anddeveloped based on based on double CPU structure of DSP chipTMS320F28335and C8051F020microcontroller multi-source. The hardwarecircuits of system are designed and developed, including DSP minimum system,switch input/output circuit, communication circuit, power supply circuit andsignal adjust circuit. Simultaneously, methods of hardware anti-interference areput forward.According to the needs of protection system in underground high-voltageswitchgear, the software programs are designed and developed, which use thedesign approach of modularized structure, including the main program, faultjudgment and handling subroutine, communication subprogram, and liquidcrystal display subroutine, etc. Meanwhile, data acquisition methods and relatedalgorithms of protection system are analyzed, and methods of softwareanti-interference are proposed.Based on existing test conditions of laboratory and cooperative unit ShanxiJincheng anthracite mining group Co. Ltd., the protection system debugging ofhigh-voltage feeding switchgear for mining flameproof mobile substation hasbeen finished. The experiment results indicate that the performance of theprotection system can satisfy the expected requirements. Experimental resultsprove that the protection system features complete protection function, friendlyinterface, stable operation, high reliability and high sensitivity, the system canpick up the signals of mining high-voltage power grid accurately and quickly, can realize the selective short-circuit protection, overload protection,over-voltage protection function. The development of protection system inhigh-voltage switchgear for mining flameproof mobile substation is of importantsignificance to improve the reliability and safety of underground power supplysystem.