| The coal-fired power is the main form of power generation in our country andtakes up above70%of the total installed capacity for a long time. With thedevelopment toward large capacity units and large power plants in electric powerindustry of our country, security of thermal power units is becoming more and moreimportant. Auxiliary power system is an important system in thermal power plant,and damages to such auxiliary equipment as the three main engines and the fiveauxiliary engines of auxiliary power system will cause huge losses to powercompanies. In case of accident, the root cause for damages of three main enginesand large auxiliary engines is that low voltage auxiliary power system of thermalpower plant can’t supply power continuously and reliably. Especially for thethermal power plants whose automation and protection interlock logic design isunreasonable, when the station blackout happens, if the manual start-up is notoperated timely, the accident will be further expanded and the loss will be moreserious.In order to solve the main problems faced by LV auxiliary power system of thecurrent thermal power plant in case of station blackout, This paper puts forward thedesign of LV auxiliary power auto-restart system by combining with the advancedtechnologies at home and abroad. We have carried on the optimization andupgrading of LV auxiliary power system in a certain thermal power plant anddeveloped a high-automation LV auxiliary power auto-restart system. This systemcan automatically distinguish station blackout accident and then automatically startequipment to ensure safe shutdown of the auxiliary system. Moreover, the auxiliarypower auto-restart system is completely automatically operated without humanintervention, so as to avoid human negligence and misoperation worsening theaccident. Reform has gone through several stages: calculating the capacity ofthermal power plant LV auxiliary power auto-restart system, optimizating dieselgenerator, setting the function and logic of the ASCO switch, designing the functionof low voltage motor, testing before operation, and so on. The upgraded system canguarantee safe and effective shutdown of thermal power units, reduce the operationfrequency of thermal power plant operators, win precious time for turbine and boiler equipment shutdown operation, improve the security of the thermal power unit,reduce the loss caused by false operation and improve the automation level．Thesuccess of the system upgrade shows the feasibility of application of LV auxiliarypower auto-restart system and its practical value to study．The successful design and development of the LV auxiliary power auto-restartsystem is in line with our country’s current security situation. At the same time, theapplication of this system is particularly important in increasing the automationlevel of power plant electrical equipment, liberating labor force, improvingproductivity, reducing the secondary accidents caused by wrong operation,narrowing the gap between our country and developed countries in the field ofautomation, and so on. |
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