Study And Applications On Maintenance Automation Of Hydro Power Stations

Condition Based Maintenance (CBM) becomes the focus area after controlautomation and office automation in hydro power plants.Remarkable progress has beenachieved in condition monitoring.However,CBM is only one of the advancedmaintenance strategies.In order to clarify the goal of research and accelerate the modernization inmaintenance domain,maintenance automation is proposed.Maintenance automation is firstly defined as that maintenance system is developed toautomatically carry out maintenance activities for human being.These activities includeautomatic condition monitoring,automatic maintenance decisions and automaticmaintenance actions.A system operation model is given.It clearly illustrates the relationships betweensystem operating states and facility health conditions.The goal of maintenance automationis to automatically maintain facilities in good conditions as well as that of controlautomation is to automatically regulate system states to fellow the expected orbit and tocomplete the appointed tasks.The integration of maintenance system with control systemand management system is described.A condition monitoring secheme is proposed on base of the diagram of systemconstitution and its behavior descriptions:-Operating states measurement and analysis.The operating states are integratedlymeasured.They are compared with their limits.An abnormal event is recorded when thestate(s) exceed the limits.-Performance evaluation.The operation space of a turbine-generator set is dividedto operating sections such as stand-still,start-up,generation with steady load,etc.Theturbine generator set and its equipments accomplish specific task(s) in each operatingsection.The operating section is automatically identified.The performances of tasksaccomplishment are evaluated at the end of each operating section.The performanceindices are compared with the specifications in standards to detect unacceptable event(s).The variation trend of each performance index under similar operating section is made assoon as a new index is figured out or periodicly to detect performance degradationevent(s). -Fault tree analysis.All the possible causes of any abnormal event are searchedand listed on base of fault tree.-Fault or degradation diagnosis.The model based fault detection and signatureanalysis approaches are employed to analyse the suspicious equipments in order to locatethe fault or degradation.Although the maintenance has to be carried out by human being at this moment,theplan and the technics of maintenance can be concepted and optimized on the virtualmachine realized by use of 3D simulation techniques.The conception results can bedemonstrated on the virtual machine to direct the maintenance actions.Furthermore,China Yantze Power Cooperation Limited (CYPC) has started the research on the robotsfor turbine repair.So the conception results will be directly output to robots andaccomplished by robots in the future to realize complete maintenance automation.A joint study on optimal maintenance information system has been started betweenCYPC and Huazhong University of Science and Technology since 2001.The on-linecondition monitoring systems of 10 turbine generator sets and 4 transformers,the remotemonitoring and diagnosis system,and a digital emulator of turbine generator sets havebeen in service in Gezhouba Hydro Power Plant.These systems play more and moreimportant role in the analysis,diagnosis and maintenance in Gezhouba.Their successfulapplication makes significant contributions to maintenance automation。...