Study On Application Of Magnetic Controllable Reactor In Power System

With the voltage class upgrading of the electric network,the allowable value of switching over-voltage of the transmission lines are more and more concerned,multiple of over-voltage have the direct relation with insulation level,the benefit of economy is very remarkable.So it is necessary to study the inner over-voltage and its limiting measures. Arrester and closing resistor,which are extensive used to limit switching over-voltage in EHV home and abroad,is not good enough for the UHV.Magnetic controllable reactor(MCR) is one important device in voltage controlling and reactive power compensation,it attracts more attention and applies in many fields.It can adjust the capability of itself automatically and smoothly along with the change of the transmission power.Moreover,when the line transmits large power,once the transient state process happens,it also can increase the capability rapidly and present deep strong compensation.That is to say,it has the function of reducing power frequency and operational over-voltage.At first,MCR is studied both in theory and simulation in the thesis.The review of MCR is introduced.Principle of MCR is analyzed.Mathematical model is set up.And on this basis conclude its simulation model and controlling characteristics.Subsequently,simplified the UHV transmission line model based on lumped parameter withâ…¡model.The approximate expression of the power frequency over-voltage is deducted under the condition of connection of MCR.The distributing voltage along the line with different locations of MCR has been analyzed at the meantime.The transient over-voltage such as closing over-voltage,tripping over-voltage,fault over-voltage have been studied.Furthermore,the first UHV demonstration project at home has been simulating calculated.Finally,after theoretical analysis and carrying on a great deal of ATP-EMTP simulations,Based on the results,the feasibility and practicability of over-voltage restraint using MCR has been testified.At last,basing on the principle of MCR,the paper realizes the suppressing of secondary arc current,puts forward a new controllable suppression-arc coil type and gives the control strategies.