Research On The Short Circuit Analysis Of 500kV Shengle Substation And The Installation Of Small Reactor At Neutral Point Of The Main Transformer

In the past 15 years,Inner Mongolia power grid of China develops rapidly and the 500 kV extra-high voltage(EHV)power grid is under construction.The capacity of the EHV power grid which is managed by Inner Mongolia EHV power supply bureau increases quickly.The power delivered by Inner Mongolia EHV power supply bureau is mainly used to meet the power demand of Beijing.With the increase of the capacity and the strong power grid,the fault current would be higher when there is a single-phase grounding fault in the network.The characteristics of Inner Mongolia power grid is introduced firstly in this paper.Several measures adopted to limit the short circuit current of the substation are analyzed.Then the most economical and optimized method,installing small reactor at neutral point of the main transformer is chosen.The short circuit current is calculated respectively under a three-phase short circuit fault and a single-phase grounding fault.The value of the reactance is designed and the relevant equipment type adopting this technology as well as a series technical parameter are specified.Through calculation,the main transformers #2 and #4 are arranged to install small reactance with the value of 15 ?.The fault current is calculated in this paper.The type of the reactor and a series parameter are specified and the related problems are studied deeply.The technical parameters of the reactor are designed,including the power frequency voltage and current,switching high voltage and transient current,insulation level check,thermal stability and dynamic stability,and design for the rated current and capacity.The type and related construction scheme of the earthing switch are specified.The change of the protection equipment data caused by the installation of the small reactor is analyzed.The wiring mode,whole layout,operation and maintenance are designed.The neutral point small reactor is installed in the substation put into operation recently according to the study,which is a demonstration for the small reactors installation in all substations and provides more experience for design,construction and maintenance.The study is of big significance for the development of west Inner Mongolia EHV grid and provides reference to other substations put into operation.