Satety And Stability Analysis And Control In Weak Connection Self-Provided Power Gird

This paper describes the status of power grid safety and stability control,summarizes its application.Under this background,taking a large electrolytic aluminum enterprise as an example,according to the general structure of this power gird,analyzes the characteristics and the special needs,in order to ensure the safe and stable of self-provided power gird and improve the reliability,reduce losses,put forward the security stability analysis and control project in this power gird.This paper established a self-provided power grid model,analysis self-provided power grid with weak connection architecture and load characteristics,propose isolated power grid and wesk connection mode,the net line,unit,load and external contact line fault under the conditions of the possible components of overload,frequency and voltage stability,the contact line of thermal stability and the flow limit problem.In order to improve the ability of power grid to resist the disturbance,the generator and load model which is built on the engineering practice is established,using FASTEST calculation and dynamic simulation,analysis safety and stability characteristics in N-1 fault,N-2 fault and serious faults,to make quantitative analysis on the safety and stability problems,research control strategy,plan emergency control?corrective control measures and verify.According to the characteristics,based on the control strategy after checking,the combination of grid and load characteristic,establish reasonable off-line stability control system.The control system according to the large grid safety and stability control system configuration logic,set the master station,sub station,trip generator station and load shedding station with hierarchical concept.In the realization of functions,all stations monitoring the operation state of power grid elements,judge its into or out of operation,abnormal and faults,through the channel,summary in master station in order to ensure coordination and control the timing of policy enforcement,to prevent new problems caused the control,Unified decision-making by the master station,according to the analysis of the stability of decision control strategy,get the conclusion which need to take tripping generator and load shedding,The command is sent to the other station by optical fiber channel to execute the measures,and the whole control process is completed.At the same time,the control system integrates the third line of defense,if there is a serious fault in the power grid,or the actual operating conditions is difference,resulting in second lines of defense can not match the implementation of the strategy,the third line of defense,relying on some measures to keep system stability,avoid the enterprise caused great economic losses.At the end,the security and stability control system of the power grid is summarized,and the reference value of the similar network is proposed,and the future research content is prospected.