Abstract: This paper introduces the application of domestic high-voltage frequency converter in Quzhou Juhua Sulfuric Acid Plant in Zhejiang Province. The operating data after the frequency conversion of the cooling water circulating pump shows that the reform is successful and the energy-saving effect is obvious. Key words: high-pressure frequency converter, circulating pump for cooling water 1. Introduction: Zhejiang Quzhou Juhua Sulfuric Acid Factory is one of the first batch of key sulfuric acid manufacturers in China that designs, manufactures and installs itself and is the largest sulfuric acid production plant in Zhejiang Province. In sulfuric acid production process, the need for water-cooled plate cooling, cooling water circulation pump is an important production process of sulfuric acid equipment, cooling water circulation pump in the past are not speed, the use of outlet valve to control the water flow and pipe network pressure, due to equipment Selection is based on the maximum load conditions to type in the actual operation of the equipment left a larger margin, the cooling water flow and pressure through the cooling water pump out, the inlet pipe on the regulating valve to adjust, causing the motor Operating efficiency is low, resulting in power waste, in order to reduce production costs, after demonstration, the decision to use landscape brand JD-BP37-type high-voltage inverter cooling water circulating pump frequency conversion energy-saving transformation to solve the energy waste problem. 2, the user cooling water circulating pump and supporting motor related parameters: Pump Model: 500S-35 single-stage double suction centrifugal pump; Flow: 561L / S Speed: 970r / min Head: 35m Motor Power: 280KW Voltage: 6000V Current: 35.2A Speed: 985r / min 3, the new scenery JD-BP37-type high-voltage inverter 3.1JD-BP37-type high-voltage inverter Introduction JD-BP37-type high-voltage inverter using the latest IGBT-based devices, all digital, Color LCD touch screen control, with high reliability, easy operation, high-performance design for the goal of high-frequency converter. After years of research and development, the products have been widely used in metallurgy, petroleum, chemical, power, cement, water supply and drainage, pharmaceutical, papermaking, sewage treatment and other industries. Become a boutique, by no means accidental. Scenery high-voltage inverter, using a number of low-voltage inverter power unit in series to achieve direct high-voltage output, the use of 6kv high-voltage inverter, transformers have 18 groups to pay edge winding, divided into 6 power units / phase, a total of 18 A unit, using 36 pulse rectifier, the input harmonic components meet the national standard, high-voltage inverter system structure, the main circuit of the unit circuit, the bypass branch using SCR module. 3.2JD-BP37-type high-voltage inverter main technical performance 3.2.1 High-voltage source converter, direct 6KV input, direct 6KV output, without any output transformers or filters, suitable for ordinary high-voltage motors, the right Motor, cable insulation without damage. 3.2.2 high input power factor, current harmonic small, no power factor compensation, harmonic suppression device. 3.2.3 modular design of the unit circuit, easy maintenance, good interchangeability. 3.2.4 High-voltage main loop and the controller for the optical fiber connection, strong and weak electrical isolation, safe and reliable. 3.2.5 perfect fault detection, accurate fault protection and accurate positioning display and alarm. 3.2.6 Built-in PLC, to adapt to the changing needs of the scene. 3.2.7 The control power and high voltage are independent of each other, no high voltage can detect the inverter output, easy to debug on site and train operators, easy to maintain. 3.2.8 power unit after 24 hours of high temperature aging, 150% load test, high reliability. 3.2.9 Chinese Windows interface, color LCD touch screen operation. 3.2.10 can receive and output multiple industrial standard signal. 3.2.11 can print out the operation report. 4, the control principle and electrical equipment circuit diagram inverter drive control 3 # circulating pump, 2 #, 1 # circulating pump open one prepared. Now the cooling jellyfish tube pressure for a given amount, according to the process of the mother tube pressure adjustment circulating pump speed, pressure signal taken from the main network, the target pressure value is set at 0.24Mpa. 5, High-voltage inverter energy saving introduction Equipment renovation project was completed in January 2005, a high-voltage inverter test run successfully, the normal operation, the frequency of 40Hz operation to ensure the normal temperature of circulating water. The energy-saving related data: ⒌ ⒈ power frequency operating data: May 27 14:30 Operating frequency 50Hz Input current 23.8A Input voltage 6KV May 27 21:35 Operating frequency 50Hz Input current 26.4A Input voltage 6KV May 28th 08:00 Operating frequency 50Hz Input current 25.2A Input voltage 6KV May 28 21:00 Operating frequency 50Hz Input current 24.8A Input voltage 6KV May 29 06:25 Operating frequency 50Hz Input current 24.1A Input voltage 6KV Frequency average operating current 24.86A Power factor COSΦ1 = 0.85 ⒌ ⒉ inverter operating data May 27 11:00 Operating frequency 41: 55Hz Input current 13.0A Input voltage 6KV May 27 12:00 Operating frequency 41: 55Hz Input current 13.1A Input voltage 6KV May 27 13:00 Operating frequency 41: 55Hz Input current 13.0A Input voltage 6KV May 27 14:00 Operating frequency 41: 55Hz Input current 13.2A Input voltage 6KV The average operating current of inverter is 13.07A, power The factor is COSΦ2 = 0.98 Annual electricity consumption: (I × COSΦ1-I × COSΦ2) × Ua × 1.732 × 24 hours × 350 days = 718,000 kWh Annual electricity cost savings: annual saving of electricity × 0.5 yuan / kWh = 35.9 Million yuan frequency operation rate of saving 40%. Equipment operating frequency of 35Hz, you can reach the process of the water pressure, spring, winter and autumn three seasons equipment can be run at 35Hz, saving rate of 50% or so, according to the current 41Hz operation, the annual saving of 710,000 Degree, save electricity 359,000 yuan, the cost recovery period of 1.8 years. 6. Conclusion Scenery brand high-voltage inverter In Juhua AG sulfuric acid plant cooling water circulation pump application, you can make the cooling water circulation pump with the load changes in the cooling water flow to achieve the purpose of energy conservation, while the circulating pump soft-start , The protection of pumps, motors, reduce pump and motor maintenance costs, improve the cooling water circulation pump operating conditions, reducing the cost of production. In the high voltage inverter technology more mature today, I believe that domestic high voltage inverter, in various industries will have a better performance.