Application of the hottest HIVERT high voltage fre

2022-08-05
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The application of HIVERT high-voltage inverter in the high-temperature fan at the kiln end

this paper mainly introduces the application of high-voltage inverter I. random switching of multiple languages of cardboard tensile testing machine: Simplified Chinese, traditional Chinese and English frequency converter in the speed regulation and energy-saving transformation of high-temperature fan at the kiln end. Huaibei Mining Group Cement Co., Ltd. has a new dry process production line with a daily output of 2500t clinker designed by Tianjin Cement Design Institute. The high-temperature fan adopts hydraulic coupling for speed regulation, and the motor is 6kv1400kw squirrel cage motor, which is directly started. In production, the motor is started directly, which has a great impact on the electricity, and there are many faults in the speed regulation of the hydraulic coupling, and the power consumption is large, resulting in high production costs. Therefore, our company decided to carry out frequency conversion transformation of high-voltage motor for the fan. Our company uses the HIVERT high-voltage frequency converter produced by Beijing Hekang Yisheng Frequency Conversion Technology Co., Ltd. in the kiln tail high-temperature fan. This paper analyzes the application of HIVERT high-voltage frequency converter in the main motor of our company's kiln tail high-temperature fan

transformation scheme

1. The original kiln tail high-temperature fan lost 40% of its pneumatic connection when turning

motor hydraulic coupling fan aims at the problems faced by the current new material industry, such as large but not strong. The air volume is regulated through the hydraulic coupling. The opening is 35% and the air valve opening is 100%, which can meet the production requirements. The motor is a 1400kW squirrel cage motor, which has a large starting current and cannot be soft started. It always runs at full speed, resulting in serious waste of electric energy

2. Technical parameters of high temperature fan and motor

fan model w × № 30.5

air volume 460000m/h

inlet air pressure -7500pa

speed 960rpm

motor model ykk

rated power 1400kw

rated voltage 6kv

rated current 160a

power factor 0.879

3. Connection mode of high temperature fan at kiln tail after transformation

electric machine - connecting shaft - fan. The air door opening is 100%, and the motor can start at low speed

transformation

1. Type selection and performance characteristics of frequency converter

according to the motor capacity, the model of high-voltage frequency converter is: hivert-y06/173 (the rated output current is 173a, reducing the viscosity of oil and adapting to 1400kW asynchronous motor). Input voltage 6kV, 5 units in series for each phase, overload capacity 120% for one minute, 150% for immediate protection

2. Primary circuit diagram (see Figure 1)

main configuration of bypass cabinet: three vacuum contactors (KM1, km2, KM3) and two knife switch disconnectors K1, K2. Km2 and KM3 are electrically interlocked. When KM1 and km2 are closed and KM3 is disconnected, the motor operates with variable frequency; When KM1 and km2 are disconnected and KM3 is closed, the motor operates at power frequency. In addition, when KM1 is closed, K1 operating handle is locked and cannot be operated; When km2 is closed, K2 operating handle is locked and cannot be operated

Figure 1 primary circuit diagram of high temperature fan

when the motor is operating at power frequency, if it is necessary to troubleshoot or maintain the frequency converter, remember to disconnect the disconnectors K1 and K2 under the opening state of KM1 and km2

closing locking: connect the "closing permission" signal of the frequency converter in series to the closing circuits of KM1 and km2. When the frequency converter fails or is not ready, the closing of vacuum contactors KM1 and km2 is not allowed; In the closing state of KM1 and km2, if the frequency converter fails, the "closing permission" will be disconnected, KM1 and km2 will trip, and the high-voltage input power supply of the frequency converter will be disconnected

bypass input: connect the "bypass input" signal of frequency converter to KM3 closing circuit in parallel. Under the variable frequency operation state, if the frequency converter fails and the automatic operation is allowed, or the motor needs to be operated from the variable frequency to the power frequency state (press the "power frequency switching" button), the system will first disconnect the high-voltage input and output switches KM1 and km2 of the frequency converter. After a certain time delay, the "bypass input" is closed, that is, the power frequency bypass switch KM3 is closed, and the motor is put into power frequency operation

protection: keep the original protection and setting value of the motor unchanged

Figure 2 control principle diagram of frequency converter system

3. Secondary circuit and control

controller is composed of optical fiber board, signal board, main control board, interface board and monitor. The connection between each part is shown in Figure 3

4. Control mode

hivert frequency converter has three control modes:

◆ local control: it controls the start and stop of the motor from the operation interface of the frequency converter, and can complete all control of the frequency converter

◆ remote control: receive on-site switching value control through the built-in interface board

◆ upper control: receive the control of upper DCS system through RS485 interface and Modbus communication protocol

there are two common setting methods:

◆ local setting: set the operation frequency through the operation screen

◆ analog setting: receive 0 ~ 10V or 4 ~ 20mA analog signals from DCS system to set the operation frequency or the set value of controlled quantity

energy saving analysis

1. Test data after transformation

motor current after transformation/a 120 95

power factor 0.86 0.95

motor power/kw 1072.5 937.8

motor speed/r min-1 933848

motor stator voltage/kv 6

▲ Table 1 test data after transformation

are shown in Table 1 (air door opening 100%, rotary kiln operation material 180t/h)

2. Benefit comparison

see Table 1 for the measured data of normal production after the high-temperature fan changes the frequency jump speed. It can be seen from table 1 that after the frequency conversion transformation, the input power of the fan is significantly reduced under the condition that the production is normal, and the power consumption in each hour is 134.7kwh

the operation rate of the kiln is 92%, and the annual electricity saving is 365d × 92% × twenty-four × 134.7=. 24 kwh, the comprehensive electricity price is 0.55 yuan/kwh, and the annual electricity cost is saved: twenty-four × 0.55=597000 yuan, reducing carbon dioxide emissions by about 1000t

3. Impact of high temperature fan on other equipment after changing frequency and speed regulation

◆ the motor is started at low speed soft start, which reduces the impact on the motor and electricity and extends the service life of the motor

◆ stepless speed regulation is realized, which avoids the problem of unstable speed regulation with hydraulic coupling and the frequent failure of coupling in summer due to high oil temperature

◆ the ability of automatic control is improved

◆ the rotation speed of the motor is low, and the temperature of the motor bearing bush is reduced, which solves the problem of high bearing bush temperature in summer

◆ variable frequency speed regulation is used to realize real-time constant operation and improve the safety and stability of the system

at present, HIVERT high-voltage inverter has been used in our company for more than 1 year, and no fault has occurred during operation. HIVERT high-voltage frequency converter not only has convenient operation and small maintenance, but also enhances the safety and reliability of operation, with remarkable energy-saving effect, which greatly improves the economic benefits of our company

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