The simulation of the controllable reactor and it´s application in Ultra High Voltage Transmission Lines

I Fixed shunt reactors are usually used in Ultra High Voltage Transmission network, which are not adjustable, but the parameters of Ultra High Voltage Transmission Lines are changing in different working condition and operating mode. Because shunt reactors are not adjustable, the power loss of transmission lines cannot be reduced. in view of this situation this article put forward a plan which uses the controllable reactor instead of the fixed reactor in Ultra High Voltage Transmission Lines. With the continuous and smooth regulation scheme of the controllable reactor the power loss of Ultra High Voltage Transmission Lines is reduced greatly and effectively. This article makes use of the software of PSCAD/EMTDC to build up the model of the magnetic controllable reactor and introduces the theory of building up the model and the theory what makes use of the magnetic saturation to change the pereability. In the simulation case, magnetic saturation can be controlled by changing current of control side. The article greatly researches and simulates the application of controllable reactor in Ultra High Voltage Transmission Lines, and separately simulates the power frequency over-voltages, switching over-voltages. The power frequency over-voltages include three phase load rejection, power frequency over-voltage and single grounding load rejection power frequency over-voltage. The switching over-voltages include the closing no-load long lines power frequency over-voltage and single-phase reclosure switching over-voltage. The article briefly explain the principle of the phenomenon that is mentioned above which usually happen in the Ultra High Voltage Transmission Lines so as to prove the result of simulation. Further, we discovered the good effect when adding neutral point small reactor to the controllable shunt reactor, which is greatly beneficial to achieve single phase reclosure. Finally in response to the phenomenon that magnetic controllable shunt adding to Ultra High V- ltage Transmission Lines will lead to resonance over voltage. The article simulates and researches the phenomenon, analyzing the reason that lead to resonance over-voltage and put forward the method what can avoid generating resonance over voltage, so that we can avoid generating resonance over-voltage in the application of controllable reactor for Ultra High Voltage Transmission Lines.