System Design And Implementation Of Reactive Power Optimization In Long Line Light Load Power Grid

The construction and commissioning of Chaidamu-Lhasa high voltage direct current transmission project in Qinghai in 2011(referred to as Chaila direct current)and Changdu interconnected transmission and transformer project in Sichuan-Tibet in 2014(referred to as Chuan-Tibet interconnected network)greatly promoted the alleviation of various power demand problems in central and Eastern Tibet,and marked that the Tibet power network entered into Expansion period that the ultra-high voltage AC-DC hybrid system.With the development of Tibet power grid and power supply,photovoltaic grid-connected has brought obvious challenges to the voltage and reactive power operation of power grid.With the increase of demand for photovoltaic grid-connected,it is increasingly urgent to improve the level of voltage and reactive power operation control.The "long-line light-load" feature of Tibet power network is becoming more and more obvious,which results in low power transmission capacity,low voltage or over-voltage,and the resulting set disconnection,unit over-excitation,frequency and power angle instability.With the increase of line load power,the voltage through bus will fluctuate greatly when the range of transmission power values approaches the line stability limit;the voltage based on the grid-connected photovoltaic power station flows in uninterruptedly,which causes the voltage fluctuation problem.Due to the complexity of reactive power and voltage regulation environment in Tibet power grid,the existing system can not effectively solve the problem.This paper takes the Tibet power network as a pilot object,fully investigates the grid structure,DC installed capacity,capacitive reactance configuration and basic reactive power equipment of the power network,and summarizes and analyses these conditions,finds out the defects of the system and terminal,and conducts on-the-spot renovation.It studies the voltage safety and stability characteristics of the Tibet power network from both steady-state and dynamic levels,and puts forward the West Optimize the configuration of static and dynamic reactive power compensation devices in Tibetan power network to solve the problem of insufficient dynamic reactive power compensation in regional power network;study the voltage control strategies of photovoltaic power stations,coordinate optimization of reactive power control strategies such as inverters of photovoltaic power stations,SVC and SVG of photovoltaic power stations,and automatic voltage control of photovoltaic grid-connected points,to improve the photovoltaic absorptive capacity of power network;It is proposed that the existing power grid in Tibet should be planned and managed automatically and the AVC coordinated control should be realized automatically.The system uses C/S soft architecture planning,uses C# as programming language to develop,uses MSSQL Server to control system background data,The system automatically collects real-time data of equipment operation,adds system optimization algorithm,integrates photovoltaic power grid,and implements hierarchical reactive power control.Using this system in Tibet power grid,we can solve the problem of reactive power optimization,improve the transmission capacity of power transmission channels,increase the capacity of new energy to be connected to the grid,reduce the risk of power network operation,improve the work efficiency of dispatching operators.