Dual-power Mutual Support System For Large-scale Industry Sensitive Load

With the development of power systems, power grids become more complex, andthere are more and more types of power sources and more kinds of loads. Powerquality issues have become increasingly prominent, and people will pay more attention topower quality problems. As the development of high-tech industry and large industrialenterprises, especially large industrial and mining enterprises, like iron and steel enterprises,voltage interruptions and voltage sags will lead to pool quality products or lead to theproduction line paralysis in severe cases. These accidents will lead to a lot of loss toenterprise and society. Power grid in enterprise always contains more than one generator.So it is necessary to study how to transfer loads from one source to another source rapidlyand seamlessly. Transfer switch is a effective way to solve this problem, and improve thepower quality and reliability for large-scale industries.Firstly, this paper presents what is the power quality, and what cause to these powerquality problems, and how to solve these problems currently. Then, this paper focuses onimproving power quality and reliability, and studies on transfer switch. This paper proposesa novel multi-power supporting method witch transfer switches, and make a compare to thetraditional topology. This paper introduces a variety of detection methodsAC powervariables, and proposes a quick and reliable voltage detection algorithm for transfer switch.This paper summarizes the operation principles of transfer switch, and proposes fourtransfer strategies for hybrid transfer switch. This paper also realized overlapped transfer ofneutral line. This article designed and developed a400V/1000kVAindustrial prototype ofhybrid automatic transfer switch, and verified reliability and rapidity of the proposedvoltage detecting algorithm with the prototype. In the paper, a lot of experiments have beendone to prove the operation principles and the four transfer strategies, also all kinds of shortcircuit tests and high current test have been implemented. Experiment results demonstratethe prototype has perfect functions and run reliable. It is worth mentioning that theprototype can distinguish the fault point on which side of the equipment, which makes thisequipment has a strong usefulness.