Basic Study Of Leading Phase Operation For Powerformer

Powerformer, which is a new kind of power equipment and can be connected to power network directly, is introduced in this paper. One century old conventions was broken in the way that conventional generator, the generator surge arresters, the medium-voltage generator breaker and bus-bars, and the step-up transformer are all replaced by one single generating unit. Advantages of low cost, high efficiency and low maintenance also make Powerformer a promising prospect.With the increasing emergence of ultra-high voltage grid, power cable as well as the bigger and bigger gap between power consumption peak and valley in the power network, the problem of reactive power excess in power system is becoming more and more serious, and the condition of voltage exceeding upper limit turns up more often, which seriously influences power quantity and equipment safety. The simple, effective and economical solution to this problem, however, is to make some generators work in advanced phase condition while light-load or faults occur to the system. In this case leading reactive power generated will offset the unnecessary lagging reactive power and stabilize system voltage. Due to the Powerformer is a new kind of high voltage generator, the leading phase operation study of which is very significant.In this paper the design principle, feature and prospective development of Powerformer were introduced firstly. Then the necessity of generator working in advanced phase condition, its general requirement and stipulation were presented. At the same time, the factors and corresponding technological measures are put forward when generators are working in advanced phase condition.A precise method, Newton analytical method, is employed to determine static stability boundary condition. With this method, Powerformer and a traditional generator of same volume and capacity are analyzed. And the operating capacity diagrams for these two generators are drawn.Then, simulation models and system models of all components in infinite system were established by Simulink. Two conditions of different active power and external system impedance are simulated when Powerformer is switching from lagging phase operation to leading phase operation. According to the derived simulation data, the relationship of the depth of generator leading operation,external system impedance and output active power is analyzed. This is valued to the actual leading phase operation of Powerformer.Finally, the structure and operation characteristics of Powerformer are combined; magnetic field distribution of Powerformer in different working conditions is calculated; and the variation rule is obtained finally.