Application of Frequency Conversion Technology in Coal Mine Air Compressor
Coal technology 6 arc-extinguishing device working principle arc-suppression coil structure principle 1. The arc suppression coil has five iron core columns, and the middle three iron core columns are wound with high and low voltage coils, and there is no coil on the side column. The high-voltage winding end is directly connected to the grid, 3,0, the other end is connected to the ground, the low-voltage winding is connected to the open angle, and the small reactor is connected through the thyristor. 12. When the grid is working normally, the phase voltage Symmetry, that is, private +77, + weight =, therefore, must have, +, + = 4 =, that is, the neutral point of the arc suppression coil has no current into the ground. When a single-phase earth fault occurs in the power grid, the voltage applied to the phase-column arc suppression coil can be decomposed into a positive sequence component and a zero-sequence component, and the grid has a zero-sequence voltage. The current generated by the positive sequence component voltage flows through the phase high voltage winding. Because of the equal size, the phase difference 120 vector and zero will not flow into the earth, and the generated positive sequence magnetic flux is also equal in magnitude and phase difference is 12, so The sequence magnetic flux circulates between the three columns in the middle, and is a channel to each other without passing through the side column. Since there are no air gaps in the middle three columns, the magnetic resistance is small, the positive sequence impedance is large, and the positive sequence current is small, and its value is equivalent to the no-load current of the transformer. The zero-sequence current flows into the phase-voltage winding. Due to the equal size and direction, the zero-sequence flux generated is also equal in magnitude and in the same direction. The air gap and the two side columns form a channel. Since the zero-sequence magnetic circuit has an air gap and a large magnetic resistance, the zero-sequence current is large. The zero sequence inductance value can be changed by adjusting the size of the magnetic circuit air gap, thereby changing the zero sequence inductance current of the arc suppression coil. The low-voltage winding is connected into an open-angle shape, and the secondary zero-sequence voltage is taken out, and the small-sized reactor 012 is turned on by the thyristor to adjust the conduction angle of the thyristor, thereby adjusting the magnitude of the secondary side inductor current, thereby changing the zero of the primary side. The sequence inductor current is used to realize the automatic tracking compensation of the arc-suppression coil inductor current to the grid-to-ground capacitor current. The secondary coil also passes through the contact of the AC contactor, and the resistor is turned on to increase the damping rate of the power grid and limit the resonant overvoltage. 7 arc suppression coil installation technical scheme and use 1 substation 61 to install the arc suppression coil in sections with two sections of busbar power supply line, and set up 2 sets of automatic tracking compensation arc suppression coil complete sets. The substation has a total of two busbars, which are arranged in parallel and run side-by-side devices, each connected to two busbars. The arc suppression coil has a compensation capacity of 50 and an adjustable range of 45 people. That is to meet the needs of the current compensation capacity, but also reserved sufficient development space for the expansion of the power grid in the future. The arc-extinguishing coil adopts a phase-column structure, and the existing switchgear cabinet of the substation is installed in the high-voltage room of the substation 61, and the single controller is installed locally, and the 485 interface can be connected to the integrated automation system of the substation. It can realize the functions of blocking various protection trip remote control, etc. Each section uses one original high voltage switch cabinet as the arc suppression coil switching cabinet. Practice has proved that the set, 661050 automatic tracking compensation arc suppression coil device is put into operation, the operation is reliable, the indicators are well controlled, and it has significant economic and social benefits in the design and technical transformation of the mine high voltage power supply conventional system. Received date: 20080307; revised date 2008 frequency conversion technology in coal mine air compressor application will win, Liu Haidong Heilongjiang Long Coal Industry Group, Harbin 150090 and social benefits. There are 12 sets of 428 air compressors in Jixihua Coal Mine of Jixi Mining Group, of which 10 are used underground and 2 are used on the ground. Due to the speciality of coal mine conditions, the heading face is in actual production, it is impossible to achieve the same working face. The time uses the pneumatic tools, and the air consumption also changes frequently. Therefore, the working time of each air compressor is very long, and the working time of each air compressor is 7 per day. 1. The power consumption and equipment wear. Therefore, energy-saving renovation of coal mine air compressors will generate great economic benefits. 1 The status quo before the air compressor transformation 1.1 Starting method The underground air compressor adopts 660 voltage, squirrel-cage motor, and starts in the direct-start mode. 1.2 The pressure air system uses an open-loop pressure system to control the load and unloading of the air compressor through a pressure regulator. When the wind pack pressure exceeds the set upper limit value, the pressure regulator controls the air compressor unloading. When the wind pack pressure is lower than the set lower limit value, the pressure regulator controls the air compressor load, the air compressor and The motor is running at full load. 13 Disadvantages of this mode of operation The air pressure system adopts an open-loop control mode, and the supply air pressure fluctuates between the upper and lower limits, and the constant pressure air supply cannot be guaranteed. When the pressure reaches the set high limit, the unloading valve is closed, the air compressor and the motor are running empty. When the pressure reaches the set low limit, the unloading valve is opened, and the air compressor and the motor are running at full load. This operation mode is too Frequent starting of equipment and electric motors, causing direct motor starting of large air compressors or starting of motor rotor string resistance for power grids and mechanical equipment. The current is large at start-up, which causes great impact on the power grid and mechanical equipment and shortens the life of mechanical equipment. . When the air compressor is running in an empty state, its drag motor still keeps running, and the electric energy consumed is about 30 of its rated value, which seriously wastes electric energy. When the air compressor and its drag motor run at full speed for a long time, the life of the motor and air compressor transmission components is reduced, the lubricating oil consumption is also large, and the cost is increased. In addition, the temperature of the air compressor rises rapidly after the running time. Need to switch air compressors frequently. Technical data of air compressors and motors 2. Name parameter exhaust volume 3 rated pressure MJPa shaft power said rated speed name ground motor parameters downhole motor parameters rated power said rated voltage v rated motor rotor rated voltage rotor rated current A star 2 transformation program 21 selection inverter starter selection 88 company Production of people 08800 series inverter, the core technology of this inverter is direct transfer system, 1. Its performance is loose. The product has high brightness and meets the requirements. It has the following advantages and has a fast calculation speed. The main control board of the 03800 inverter adopts dual processor and dual memory, which has large capacity and fast calculation speed. Fast signal transmission. The motor driven by the human 800 can obtain the rated speed of the motor at zero speed, and does not require the reversed motor power of the optical encoder or the tachometer motor to continue to operate, as long as the motor rotates and generates electric energy, starting torque. Can achieve a motor rated torque of 200. Automatic start. Can start quickly within 0.488 under any conditions. Precise speed control. The dynamic speed error of the human 800 is open-loop application, which is 0.4. 19 4 7 298 air compressor is a piston air compressor, which is a constant torque load. The control inverter with 22 inverters is equipped with two types of control: pressure closed loop control and open loop control manual adjustment. There is a selector switch. Make a selection. In normal operation, the pressure closed-loop control method is adopted, and the actual air supply pressure of the air compressor is detected by using a pressure transmitter, and compared with the set value of the supply air pressure, the å·® of the differential air compressor obtained by comparison is kept empty. Pan's supply air pressure is constant at the set value. The potentiometer and digital display for the wind pressure setting are arranged on the cabinet door of the inverter control cabinet, and the operation driver can conveniently set the supply air pressure. In order to make the pressure transmitter malfunction, the frequency conversion system can also work in an emergency. The frequency converter can also manually adjust the motor speed by using a potentiometer, and adjust the air supply pressure of the air compressor within a certain range. The cabinet door on the inverter control cabinet is provided with a frequency conversion fault reset button. When the inverter is faulty, the operator can conveniently reset the fault. The contact point of the original monitoring device of the air compressor is introduced into the inverter control circuit for interlocking. When the pressure and other parameters of the air compressor exceed the high limit value or a water cut signal occurs, the frequency conversion operation is automatically stopped. In addition, a cooling fan is arranged at the bottom of the 2 motor drag motor, and the motor is cooled when the motor runs at a low speed, which has a good effect. Benefit Analysis The air compressor is powered by the inverter to achieve soft start of the motor without any impact on the power grid and equipment. The equipment generates low heat, does not need to switch equipment frequently, and the equipment maintenance is greatly reduced. The machine is repaired twice a month and the chassis is replenished, which greatly reduces material costs and accessories costs. I passed the test of one 428 machine and made one set. 1 1 Calculated by 0.5 yuan, each equipment can save 100,000 yuan per year. The maintenance cost and material cost saved are still around 30,000 yuan per year. If two air compressors use one inverter, the input can be reduced and the number of air compressor switching can be reduced. The conversion of frequency conversion speed regulation needs to invest 250,000 yuan. There are 12 sets of 8 air compressors in Jixihua Coal Mine of Jixi Mining Group. If they need to be transformed, 7 inverters should be used, with a total investment of 1.75 million yuan. The annual savings can be 1.56 million yuan and 12 units of 130,000 yuan. The annual economic benefits are very impressive. The air compressor uses the inverter drive to achieve soft start constant pressure air supply, which improves the efficiency of the equipment and prolongs the life of the air compressor. It is of great significance to reduce maintenance costs and save electricity. Gantry Robot,Gantry Robot Arm,Truss Manipulator,Gantry System Cartesian Robot Qingdao Jiujin Machinery Co., Ltd , https://www.jiuinmachinery.com