Design Of Emergency Power Supply System For Important Power Users

According to the notice of national energy administration on printing and distributing the notification of configuration of power supply and self provided emergency power supply for important power users(GNS[2014]No.304):more than 50%of the power supply configuration for important users does not meet the requirements of about plus,and more than 50%of the important users are not equipped with self provided emergency power supply.It can be seen that for the important power users who are forced by the state,the configuration rate of the self-contained emergency power supply is not up to the requirements,and the civil ordinary power users are not able to meet the requirements of the configuration rate.But with the rapid development of social economy and industry,people rely more andmore on electricity.Zero blackout is the requirement of people to the power industry,and it is also the goal of the power industry itself.For the urban area distribution network,there are unreasonable wiring,users are affected by maintenance and power failure,how to carry out low-cost and simple transformation from the user end,design a self-contained emergency power system that meets the specification requirements,has high cost performance,easy operation and easy maintenance is particularly necessary.In this paper,based on the project example,in order to meet the needs of different users for power quality,a scheme of uninterruptible power supply combining diesel generator and power ups AC/DC power supply system is proposed.The load is calculated by the method of demand coefficient and power area.The capacity of diesel generator,transformer and frame circuit breaker are determined by the calculation results.According to the design requirements and capacity,the equipment selection is carried out,and the protection setting value of the incoming circuit breaker is determined based on the equipment selection results and the calculated load size.In this paper,the three bus sectionalized power supply mode with two incoming lines and one diesel generator as standby and the three-stage power distribution mode with three stages are designed.In order to achieve the purpose of automatic input of diesel generator,the automatic input device selects PLC to automatically switch between two incoming lines and one standby power supply system,so as to meet the requirement that the operation mode can automatically switch to the standby power supply when either or both incoming lines of the two incoming lines are cut off,ensuring the power supply stability of the system.The control system has the functions of live display,operation,alarm,reset,locking indication and overload load reduction.The design of the distribution system of the self-contained emergency power supply is standardized,the control device is easy to operate,suitable for maintenance and high reliability,which provides a design idea for the transformation project of the distribution system of small and medium-sized power users without the self-contained emergency power supply.