The Geomagnetically Induced Currents Prevention Technology Based On The Average Allocation Principle

Geomagnetic storms generate geomagnetic induced currents in the power grid,which are quasi DC.When they flow through the transformer,they will cause transformer half wave saturation,resulting in vibration,noise,temperature rise and loss of reactive power.Serious accidents will result in Transformer Damage and power system voltage drop.China's 1000kV UHV AC power grid started building in 2009,whose transmission lines use 500 mm2 eight split specifications.The DC resistance of the power lines is relatively small.The GICs of our future UHV grid will be large,and this paper studies GICs prevention and control technology.Using the GIC-benchmark standard which is put forward by American Electric Power Research Institute(EPRI)and other units,this paper calculate the GICs of 1000kV UHV power grid in the East China and 750kV and 330kV UHV power grid Gansu province at the power field in 1 V/km,analyzes the influence of the grid size of GIC,such as power grid structure,electric field.voltage,and the characteristics of high GICs node.On this basis,according to the average allocation principle,comparing capacitor.resistor and capacitor fixing method,adjustable resistance and capacitance method,this paper put forward a design scheme of grading resistor adjustment device.The research shows that when the direction of electric field is the same as the direction of power grid extension,the GICs of the power grid is larger,and the GICs of the terminal substation of the transmission line is larger.The grid with higher voltage level is much more affected by the power grid GICs.In the control measures.the combination of adjusted resistance and capacitive device can effectively reduce the number of installation and achieve economic and effective management.On the treatment device.the designed grading resistor device can more flexibly cope with the influence of magnetic bias current of different sizes.It is a reliable device to control GICs.In this paper.through the study of China's large-scale power grid GICs calculation,analyzes the distribution characteristics of large-scale power grid GICs.the existing GICs control scheme and control technology are analyzed and compared,and has proposed a classification regulation resistance device,has an important significance on the prevention of large-scale power grid GICs...