Research On Distributed Reactive Power Compensation To Improve The Residual Voltage Of Bus Bars In Factory

The upper end capacity of the small and medium capacity substation power grid is too small,and once the short circuit fault occurs during operation,the residual voltage of the grid bus will be greatly reduced,leading to substation trip and power outage,causing serious economic losses.In this paper,through the short-circuit calculation of the power system,the reactive power required to compensate the bus residual voltage of the system to the rated level is obtained.The original factory plans to use SVG centralized compensation to compensate,but this method plus equipment,cable,plant and other costs up to tens of millions.In this paper,the method of distributed reactive power compensation is proposed to increase the bus voltage,and the synchronous motor and inverter are used to increase the residual voltage of the busbar to normal working level.Only need to add additional distributed reactive power compensation controller equipment,plus the wiring to the system,the total cost is less than 300,000 yuan,which greatly saves the cost,and the response is fast,which has wide promotion value for small and medium capacity power systems.In this paper,the short-circuit calculation of short circuit,short circuit and transformer short circuit of a 110 kV substation is carried out,and the residual voltage of the short-circuit busbar is analyzed.At the same time,the method of distributed reactive power compensation is proposed.Distributed reactive power compensation consists of two parts:(1)forcibly exciting the synchronous motor for reactive power compensation;(2)using the inverter double-loop control system for reactive power compensation.This paper also analyzes the method of calculating the short-circuit current fast judgment,which can quickly judge whether the system has a short-circuit fault according to the rate of change of the current in the system,and analyze the harmonic sensitivity to improve the accuracy of the short-circuit fast determination.Finally,the control system of distributed reactive power compensation to improve the residual voltage of the busbar in the factory was designed and successfully applied to the 110 kV substation.Until now,there has been no trip or power outage in the substation.Therefore,the method of distributed reactive power regulation to improve the residual voltage of the factory busbar is feasible from theory to practice,and has wide promotion value for small and medium capacity power systems.