Experimental Research On Capacity Increasing And Transformation Of Generator Transformer Unit System In Tiaoshun Power Plant

With the further deepening of the power system reform,coal-fired power generation enterprises must maintain a leading position in the increasingly fierce competition in the power generation market.It is necessary to objectively and comprehensively analyze the system energy consumption sources of power plants and apply contemporary advanced technology to increase the capacity of major main and auxiliary engines.They must complete energy-saving and consumption-reducing transformation,digging the energy-saving and consumption-reducing potential of the unit.They should improve the output of the unit,and reduce the coal consumption level of the steam turbine generator set and production costs to improve economic benefits.Among them,the expansion of existing generator sets is one of the important means.In order to improve the efficiency of the unit and increase the competitiveness of the unit,Zhanjiang Tunshun Power Plant will increase the capacity of the2*600MW generator and transformer system,and increase the rated load of the turbo generator from 600 MW to 630 MW.At the same time,they will increase the main transformer from 720 MW to 760 MW.Correspondingly,the excitation system is expanded and the 19245 A rated current is increased to 20207 A.Firstly,by calculating the temperature rise of each component of the steam turbine generator,the status of stator insulation,end fixing,ventilation cooling,etc.are analyzed,and the feasibility of capacity expansion of turbine generator related auxiliary equipment is studied.Referring to the successful experience of domestic and foreign steam turbine generators for capacity expansion and transformation,the main technical measures and construction schemes for steam turbine generator capacity increasing and transformation are proposed,and the turbine generators are to be capacity-increased.The stator core loss and temperature rise and the stator are modified before and after the transformation.The natural frequency measurement and modal analysis of the winding end,and the cold water flow in the stator bar and the phase-in operation of the generator set are used to study the effect of steam turbine generator capacity increase.Secondly,the calculation method of temperature rise and cooling of transformer is briefly introduced.The temperature rise and the temperature rise of the transformer oil before and after the main transformer capacity increase transformation will be analyzed in detail.Through the calculation of the short-circuit current of the main transformer,the dynamic stability and thermal stability of the short-circuit after the transformer capacity`s increasing and transformation are verified.The feasibility of a solution to increase the cooling capacityof the cooling system to achieve transformer capacity expansion is demonstrated.Finally,according to the changing parameters of generator and main transformer capacity,the excitation system will be designed and calculated.The thyristor rectifier and the de-excitation switch as well as the upgraded excitation regulator and other equipment will be replaced,and the generator short-circuit test and generator will be no-load test,zero-boost test,and excitation regulator test are used to verify the reliability and stability of the excitation system.At present,the experience of capacity expansion and transformation of the 600 MW unit has less experience.The transformation of the generator group system of the #2 unit of the Tunshun Power Plant has been successfully completed and put into operation,and no faults and abnormal conditions have occurred,which proves that the transformation plan of this paper is feasible.It has certain guidance and reference for the capacity expansion of similar units.