introduction
my country's coal mine is only 5086.81 × 10 △ t standard coal in 2005, 3.86% and 3.49% of total energy consumption and total power consumption in total. Therefore, the coal industry is both a large capacity, but also a large energy consumption, and it is also a major energy-saving potential. At present, there is an urgent need for energy-saving and energy saving and energy saving and energy saving and energy saving and power reduction in my country's coal mining industry, serious mechanical injury and low degree of automation. According to statistics, according to 30% of the power saving rate, the annual electricity potential of inverter speed regulation technology is at least 10 × 108 ~ 15 × 108 kW · h. Therefore, using frequency conversion technology to save energy-saving and transformation of existing motor equipment, it is to solve high consumption and low-efficiency measures in my country's coal industry.
Reconstruction of Hivert High Voltage Frequency on Coal Mines
1, mine hoist
As a working machine under the mine downhole and the ground, mine hoist is a large winch. Use a wire rope to drive the container (can cage or bucket) to raise down in the coal mine well, complete the task of transporting materials and personnel. The mine hoist is gradually evolved from the original water feed tool. The modern mine hoist has a large amount of increased speed, and has developed into an automatic heavy mine machinery for electronic computer control. As shown in Figure 1 is the structure of the mine hoist. Figure 2 is the principle of working after the transformation of mine hoist work.
Figure 1 Mine hoist structure diagram
Mine hoist working principle after the second transformation
Unrocated mine hoist has a low work reliability, high failure rate, poor stability, and extensive energy consumption. The working steps of the mine hoist after transformation of high voltage inverters are shown below.
Figure three modified mine hoist work steps
For the retrofitting hoist, regardless of the correction, it is the same as the working process, which has the same start, acceleration, high speed stable operation, deceleration, low speed crawling, brake parking and other six stages. Each time to complete a lifting action, it is related to the system's running speed, acceleration, and depth of the oblique well. The size of the acceleration of each segment is determined according to the process, and the operation time is determined by the operating worker according to the situation. The work of each stage in the figure is as follows:
1) The first stage T1: The string car is filled with coal in the well surface of the well, and a contact signal is sent to the wellhead hoist operator. The operator will reply to a signal to the bottom of the well and then boot. The heavy bus started from the bottom, and the air car started in the wellhead position. 2) Second stage T2: After the heavy car starts, accelerate the frequency of the frequency converter to run, the medium speed is short, just a transition section, the device is not problematic, and then accelerate to normal operation. speed. 3) The third stage T3: The heavy bus is stably operated with the maximum speed of the frequency converter frequency of F2. Generally, this process is up to 4) The fourth stage T4: The operator sees the heavy-drive quick speed to the wellhead, such as deceleration time When the setting is short, the inverter brake unit and brake resistance functions, and does not cause too fast trip. 5) The fifth stage T5: The heavy-cart deceleration to the low speed crawling at the low speed of the F1 speed, which is convenient for parking at a predetermined position. 6) The sixth stage T6: When the parking position is fast, the inverter immediately stops, the heavy car is slowed down to zero, and the operator sends a contact signal to the downhole, the entire lifting process ends.
The above is the manual operation program, or it can work according to the PLC automatic operation. The reliability of hoist work after using HIVERT high-pressure frequency conversion is improved. Since the inverter uses imported electronic devices, long life, and has a perfect protection function, it is used to improve winch control, and its reliability is high, and the failure rate is reduced. Usually, both the inverter uses magnetic flux vector control, so that the speed control accuracy of the AC motor is very high. Stable frequency conversion technology applications reduce the work strength of the maintenance personnel to the substantially no maintenance of the hoist. The use of vector control systems can make the speed range wide, which belongs to stepless speed, and the stability is good at low speed. After using the inverter to control the hoist, reduce the operating noise, heat generation, improve the site environment, and make energy consumption reduced. The energy saving effect is significant, and it can reach more than 30% of the measured measurement. The control system on-site change control is very simple, and the installation and commissioning is easy. High degree of automation, simple operation, reduce driver labor intensity and difficulty.
2, belt machine
The use of the hoist is basically reasonable, and the belt machine also transports coal from the downhole to the ground. The difference is that the power of the belt machine is greater, its start and operation mode is started after the rotor winding is started after booting the rotor winding, and the hydraulic coupler is switched to the belt machine. Figure 4 is the principle of coal seam work, Figure 5 is a schematic of the belt machine.
The working principle of the belt machine is that the belt machine is moved by a driving hub, and the belt is moved by a tension deformation and a frictional force to move the object on the support roller. The belt is an elastic energy storage material that stores a lot of potential energy during the stop and running of the belt, which determines the way the belt should be started when the belt is started. Most of the domestic coal mines use a liquid coupling to realize the soft start of the belt machine. Adjust the mechanical efficiency of the hydraulic coupler at startup to start the motor no-load. Although the rotor string resistance improves the starting torque and anti-depressive airborne start, the start current of the motor is still very large, not only causes the dramatic fluctuations of the grid voltage, but also cause mechanical impact and fever in the motor. At the same time, when a liquid coupler is soft, the loading capacity is highly caused by the short start time, and the belt is reduced, and the strength of the belt is required. In addition, the long-term operation of the liquid power coupler can cause the internal oil temperature rise, metal parts wear, leakage and efficiency fluctuations, not only increase maintenance difficulties and cost, pollute the environment, but also drive the same belt for multiple machines It is difficult to solve power average and synchronization problems.
After frequency conversion technology, the belt machine thoroughly realized the soft and soft stop operation of the belt conveyor, so that the belt machine was more performance stable in the work. The system's power factor is more than 0.9 throughout the process, which greatly saves reactive power. After the drive is driven, the total transfer efficiency of the system is 5% to 10% higher than the efficiency of the hydraulic coupling. After the retrofit system, the system can automatically adjust the output frequency and output moment according to the load change, and change the mode of the previous motor power frequency running, which extent saves power consumption. Moreover, the use of high voltage inverters in the four-year-limited implementation of the belt machine energy feedback function, further causes the energy consumption of the belt machine to reduce the maintenance and maintenance cost of the liquid coupling. More improved in energy conservation and environmental protection.
3, coal mine main wind turbine
Coal mine main ventilation is one of the four major equipment of the coal mine. The main sector fan has an important position in coal mine production. It is the main ventilation of the mine. It is constantly running 24h 24h, which is the "breathing" system of the entire mine. With the continuous extension of mining and excavation, the roadway is extended, although the air volume is basically unchanged, but the wind pressure required by the downhole is increasing, and the wind turbine needs to be increased. Mine generally selects fan models in the most difficult period in each stage of mining. When the mine selection is selected, the motor power is equipped according to the actual ventilation parameters, and the method is as follows:
N-desired motor power, the total power (kW) of the I, II-level motor; PST-mine is the most difficult period of time (PA); Q-mine is the most difficult period (m3 / s); ηST- Press PST, Q parameter checks the actual operating conditions efficiency of this sample; K-power storage coefficient, generally take K = 1.1 to 1.15.
Fig. 6 is a schematic diagram of the structure of the main ventilator of the coal mine, and Fig. 7 is the physical map of the coal mine main ventilator. Figure Six coal mine main ventilation structure diagram
Figure Qi coal mine main ventilator physical map
The conventional coal mine ventilator has a "electric tiger", leading to serious electricity waste. It is difficult to start, and the mechanical damage is serious. The main fan fan is launched, the starter is large, and the insulation of the motor has a large threat, and even when the motor is severe. The uniaxial torque caused by high voltage motor during startup causes a larger mechanical vibration stress in the fan, which seriously affects the life of the motor, fan and other machines. The degree of automation is low. The main fan fan relies on manual adjustment, and there is no automatic real-time adjustment function of the air volume, and the degree of automation is low. In the fault state, such as a short circuit will have a serious impact on the normal production of mines.
If the inverter has problems, it will affect the operation of the miner, and even affect the safety of life. Therefore, this aspect is very high for the quality requirements of high voltage inverters. The Hivert high-voltage drive has a high stability characteristic, which can continue to maintain the normal operation of the ventilator. After the mine ventilator is used inverter speed, electric energy is saved, and can be easily accelerated according to the air volume requirements of the roadway, avoiding waste, the application effect is very ideal. And inverter energy conservation, saving a large amount of energy. The fan is no longer in the full load state due to the variable frequency transformation.
Since the inverter retrofitting the fan can realize the inverter soft start, avoid the impact of the start current, not only no impact on the grid, but also start or stop at any time. After performing frequency conversion modification, most of the working hours of the fan run at a lower speed, which greatly reduces the mechanical strength and electrical impact of the fan operation, which will greatly extend the service life of the fan and reduce the maintenance strength.
It should be noted that the coal mine has a variable frequency speed of the cyclone, and in general, the operating frequency of the two motors is required to ensure that the motor speed is consistent. Avoid a high speed, low speed, forming a wind resistance, affecting the normal operation of the fan.
Conclude
my country is the world's production coal, and is also a country with high tons of coal power consumption. Due to technical, management, system, the labor efficiency of most coal mines is low, and the coal mine mining industry in my country should be fundamentally purposeful. Through many practical applications, high-voltage inverters can be used to achieve good operating results and economic benefits in coal mine system reform. Under the big situation of the national advocated construction, the high-voltage frequency conversion transformation of coal mines is becoming a sunny sun industry. Huitang Hivert high-voltage inverter is committed to strengthening cooperation with the coal mine industry with stable quality and good service to create a better future. Technology area
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