Reactive Compensation Research Of Arc Furance Load Based On The STATCOM

With the increase of nonlinear loads in the electric network, the power qualitycaused by these loads. such as harmonic, reactive power, three phases asymmetrical andvoltage flicker aroused more and more attention, Arc furnace, as the main equipment inthe steel-making industry, it has been paid more and more attention. At the same time,as a representation of the impact loads, its harm to the power grid is self-evident; thegovernance of electric arc furnace has become a research hotspot.At first, this paper summarizes the existed electric arc furnace load models, thenexpounds the process of deducing the of the electric arc furnace.Because this model canreflect the arc furnace harmonic characteristic only, it cannot reflect phase differencebetween voltage and current, so in this paper, it puts forward time-varying impedancemodel called comprehensive load of electric arc furnace which based on the nonlineartime-varying resistance model to join the reactance. The model not only can reflect thearc furnace harmonic problem, but also can reflect its reactive power problem.The paper analyses the actual voltage current curve achieved from the arc furnaceload, then uses particle swarm optimization (pso) algorithm to identify the parameters ofthe time-varying impedance model which is proposed. The simulation waveform andthe actual current waveform are consistent, it shows that the improved model reflectsthe arc furnace load harmonic and reactive power characteristics in some degree.Traditional current detection methods and the current detection method withoutphase-locked loop are introduced in this paper, it also analyses the disadvantages of thetraditional current detection methods. And the detection method without phase-lockedloop can ensure the current detection accuracy, at the same time,it can simplify thecircuit, and reduce the cost. The paper uses the traditional current detection method andimproved current detection method to detect the actual electric arc furnace harmonicand reactive current, from the result,we can see that the method without phase-lockedloop in the actual detection of arc furnace load current harmonic and reactivecomponent is feasible.Finally, the nonlinear time-varying impedance model is used to make simulationresearch on the governance of electric arc furnace using STATCOM.We can see that thenonlinear time-varying impedance model reflects the actual voltage and currentcharacteristics of electric arc furnace. According to the actual current, we can obtain afitting curve which can be used for electric arc furnace control simulation system. Thecurrent harmonic content of the system side is greatly reduced after inputtingcompensators, and because of the compensation system, the current and voltage keepthe same phase, it is very useful to reduce the reactive power pressure on the systemside. It can be concluded that the improved current detection without phase-locked loop can be used for the actual governance of electric arc furnace load.