Design And Implementation Of Provincial Synergy Automatic Voltage Control Technology For 500kV Substation

Voltage level is an important indicator of power grid operation.The voltage of each node varies with the load.When the voltage exceeds the specified value,it will affect the safe,economic and stable operation of power grid.The change of system reactive power will lead to the fluctuation of grid voltage level.In order to ensure that each node of the power grid has a qualified voltage and a certain power factor,it is necessary to take effective voltage regulation and reactive power compensation measures for the power grid.The reactive power compensation is usually realized by shunt capacitor,while the node voltage regulation is realized by on load tap changer.At the same time,reactive power compensation also affects the node voltage level,which needs to be considered in voltage control.The method of manually adjusting node voltage is complex and heavy workload.Automatic voltage control(AVC)technology can effectively improve the voltage operation level of power grid,which is the fundamental method of voltage and reactive power regulation in China.At present,voltage and reactive power regulation of 500 k V substation in Guangdong power grid is mainly manual regulation,and the further improvement of voltage quality of the whole network is limited.This paper discusses the AVC technology scheme of 500 k V substation for Guangdong power grid,in order to improve the voltage quality and economic operation level of Guangdong power grid.According to the difference between the measured value and the target value of the node voltage and power factor,AVC realizes the closed-loop control of the voltage and power factor by adjusting the tap of the onload tap changer and switching the capacitive reactance according to the designed control scheme,so as to keep the node voltage and power factor within the required range.Because reactive power control will affect the voltage level,it is necessary to take certain pre-judgment measures in the control scheme to test the impact of reactive power control scheme on the node voltage.The 500 k V substations in Guangdong Province are widely distributed,and the voltage and reactive power regulation in different regions are scattered,so it is impossible to realize the centralized management of reactive power optimization and voltage regulation in the whole network.In order to meet the demand of regional voltage regulation and the goal of reactive power distribution optimization of the whole network,this paper designs a hierarchical distributed AVC scheme,which is divided into three layers: provincial side,local side and 500 k V substation.The provincial side completes the global reactive power distribution optimization,and sends the voltage planning curve and reactive power control target value to the local side.The local side completes AVC strategy generation and remotecontrol command distribution of 500 k V substation.The 500 k V substation is executed according to the remotecontrol instruction.500 k V substation completes real-time voltage and power factor measurement and uploads them to the local side.The reactive power reserve capacity of the local side is calculated and uploaded to the provincial side.The instruction and data upload are completed through the special network of power grid.The paper also designs voltage and reactive power AVC control strategy,reactive power compensation equipment security strategy,provincial communication and other auxiliary functions of 500 k V substation.This paper completes the realization of AVC design scheme of 500 k V substation in Guangdong power grid.It includes application deployment,function localization,independent control of voltage and reactive power,provincial and local coordinated reactive power control,etc.The abnormal application and its maintenance and treatment methods are summarized,and the AVC operation management process of 500 k V substation is specified.The paper completed the AVC setting and AVC closed-loop test of 500 k V Zhenzhou station in Huizhou area.The equipment action is in line with the expected results.Compared with the previous500 k V substation regulation mode of reactive power and voltage,the AVC implementation scheme not only achieves the goal of power grid security,but also has the flexibility and convenience of reactive power and voltage regulation.It greatly reduces the dispatcher’s workload of voltage regulation and improves the voltage qualification of 500 k V substation,which makes Guangdong power grid has the ability of overall planning and decentralized regulation.It can be extended to AVC application of other provincial dispatching system.