The Research On The Simulation Of Four-Phase Power Transmission System

High-phase order power transmission is an important method to increase the power density because it can obviously decrease the surface potential gradient of the transmission conductor. The research and field experiment operation have been carried out for more than twenty years in the USA and other countries, and a lot of notable results have been obtained. In the past, the research for multi-phase transmission system is confined to the multi-time phases of 3, that are 6, 12 phases, and so on. However it is difficult to suspend the multi-phase conductors, furthermore the pole structure is complex, and the cost of transmission lines is high and the types of fault for multi-phase transmission increase rapidly. All of these defeats constrain application of the six-phase and over six-phase transmission systems. Four-phase transmission system has the least possible even phases. It has the advantages and overcomes the disadvantages of multi-phase power system. Although the four-phase power transmission method is new, the technologies are roughly similar to those of the exiting three-phase transmission system and technically there are no difficulties to apply it, and therefore the four-phase power system can be developed and applied by seizing the opportunity of the fast booming power industry in the 21 century.The key equipment of four-phase power transmission systems is a three-phase to four-phase transformer and the inverse transformer. Principally, when the winding-connection scheme is adopted to add a set of auxiliary windings on the two-phase side of a balance transformer, we can get a three-phase to four-phase transformer. But in fact, there are many windings on each leg of a balance transformer, and the winding impedance relationships that the balance condition requires are strict, so it is difficult to design and make such transformers. If adopting the connection scheme of dual windings, the windings on single leg will increase almost doubly. It is more difficult to satisfy the balance condition and probably it will confront conflict when arranging these windings, so parameters of various phases can not be balanced. The three-phase to four-phase transformer with a four-phase four-leg structure solves the problem. The windings on each leg of this transformer are not more than three. It is the simplest form among transformers in this kind. For evaluating the relationship between the error of winding impedance and the performance of the three-phase to four-phase power transformer, this paper uses"Matlab"as a digital simulation platform to exam the mathematic model and analyze the balance condition as well as...