Junqiang Liu、Rong Dai、Yunxu Li
                                                                    （ Shenzhen Cumark New Technology Co.,Ltd  Guangdong Shenzhen 518108；）

Abstract: At the end of 2014, Shenzhen Kumak New Technology Co., Ltd. produced ES9000 series high-voltage inverters with the same disturbance-free switching function, and successfully realized the same period of non-disturbing switching control on 1400KW/10KV high-voltage asynchronous motor of Xinjiang Yihe Biological Co., Ltd. The function greatly reduces the investment of the owner unit and obtains good economic and social benefits. This article describes the project in combination with the characteristics of equipment operation. Key words: synchronous uninterrupted switching; high-voltage motor variable frequency soft start; ES9000 high-voltage inverter; 1 Introduction Xinjiang Yihe Biological Co., Ltd. (hereinafter referred to as “Biology Factory”) is a company engaged in deep processing of corn. It was incorporated in April 2011 and is located in the 66th Regiment Department of Huocheng County, Yili Prefecture, 20 kilometers away from Yining City. The land is about 230 mu and the registered capital is 78 million yuan. The company produces corn starch, L-phenylalanine and other aromatic amino acids, and continues to extend the industrial chain in the field of bio-fermentation, and develops in the direction of deep processing, high technology and high added value. The company's L-phenylalanine project has a total fixed assets investment of 350 million yuan. The first phase of the project has a fixed asset investment of 160 million yuan. It was completed and put into operation in October 2012. It can produce 90,000 tons of dry starch and 30,000 tons of glucose syrup per year. The fixed assets investment of the second phase project was 190 million yuan and it has been completed and put into production. After the project is put into production, the estimated output value will reach 500 million yuan. The biological plant has self-generating capacity, generator rated voltage KV 10 , capacity MW 6.

Due to the limited power generation capacity of the diesel power generation system, large equipment driving and parking have an impact on the grid capacity, which affects the stability of the power grid. After careful investigation and calculation, Shenzhen Kumak New Technology Co., Ltd. and the technicians of the biological plant decided to adopt Shenzhen Kumak New Technology Co., Ltd. through repeated investigation, calculation and testing according to the requirements of the biological plant process requirements and equipment operation requirements. The ES9000 high-voltage inverter with synchronous switching function is used to reduce the capacity of diesel generators and reduce the investment quota. At the same time, the motor bearings, fan bearings and blades are protected by the soft start of the inverter to reduce the power frequency to the motor and load.

2 system principle 1. Reasons for on-site renovation The biological plant has 2 centrifugal air compressors and is equipped with asynchronous motors. The rated power is KW 1400 and the rated voltage is KV 10 . When the air compressor is working normally, it is in the power frequency operation mode, and there is no speed regulation requirement. Motor starts directly When the motor starting current stI is 4 to 7 times the rated current NI (372.8A to 652.4A), and the starting torque stT is 0.9 to 1.3 times the rated torque NT, the starting current is large but the starting torque is not large.