Research And Application Of Start-up Technology Of Standby Transformer In Power Plant

In the face of global energy security,deterioration of the ecological environment and tremendous pressure on the climate change,the energy conservation has been more emphasized heavily recently.In order to ensure the continuity and stability of the power supply,the power plant needs to be equipped with a reserve transformer so that the power supply can be supplied normally when the plant power is lost.In the past,in order to improve the reliability of station service,reserve transformers have taken hot reserve mode of operation,but this way will bring a lot of no-load loss.Aiming at reducing the no-load loss of the reserve transformer in the power plant,this paper examines the feasibility of standby transformer from a hot reserve mode to a cold reserve mode.Firstly,the use,classification and working principle of the transformer is introduced.Through the introduction of the plant power leading to the power plant standby transformer,this paper analyzes the abnormal working condition of the transformer and explains the transformer protection configuration.Then,the problem of inrush current caused by the cold reserve mode of the transformer is analyzed.The RTDS test using the parameters of Linhe power plant is adopted,and the optimal closing angle is determined by analyzing the magnitude of the inrush current at different closing angles,and the optimal closing sequence of high and low pressure side is determined by simulation of different closing sequence of high and low pressure side.Then,the cold reserve mode of the transformer and the voltage maintenance of the auxiliary power bus are concerned.The switching function of the fast cutting device is verified by simulation too.The feasibility of the cold reserve mode is verified by the influence of the inrush current on the differential protection and the bus voltage maintenance.The feasibility of adopting the cold reserve mode of the reserve transformer in Linhe Power Plant is verified by the RTDS model simulation of the actual data of Linhe Power Plant.Then on the basis of simulation verification,combined with the actual situation of Linhe power plant the transformation program is designed.In order to ensure the smooth operation of the transformation and the safe operation of the unit,the aided experimental is also designed.Finally,the economic benefits of the transformation are measured,according to Linhe power plant typical annual loss of spare transformer.After the transformation program,about 20 million electricity costs can be saved every-year,and the transformation costs can be recovered about a year and a half or so.In addition,the transformation can effectively increase the service life of transformer,reducing production costs indirectly.