High-voltage motor winding automatic heating insulation recovery device and operation method

Abstract

The invention discloses an automatic heating insulation recovery device for a high-voltage motor winding and an operation method, and belongs to the technical field of automatic control of electrical equipment. The high-voltage motor winding automatic heating insulation recovery device comprises an insulation recovery system and an installation cabinet body used for containing the insulation recovery system, and the insulation recovery system comprises a detection sensor, a man-machine interaction device, a PLC logic operation controller and a power supply mechanism. The problems that in the prior art, only a motor stator is powered on and heated, the heating efficiency is low, and the functions of real-time monitoring and automatic power-on and power-off of a heating loop are lacked are solved. A motor locked-rotor effect and a current heat effect are utilized, current is introduced into the motor stator winding to heat the motor stator winding, the rotor is locked, and locked-rotor current is generated after rotor winding locked-rotor to heat the rotor, so that the heating efficiency is higher, the insulation recovery speed is higher, the motor is put into operation as early as possible, and the influence on production is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of automatic control of electrical equipment, and in particular to a high-voltage motor winding automatic heating insulation recovery device and an operating method. Background Art

[0002] The insulation requirements for high-voltage motors are higher than those for low-voltage motors. At the same time, the assembly process of high-voltage motors is complex, and the installation steps in coordination with mechanical equipment on site are cumbersome and require high precision. When the insulation of the high-voltage motor at the operation site decreases due to factors such as harsh working environment and long-term shutdown, we need to treat the insulation of the motor. There are two methods currently used. One is to set up a drying lamp for baking, and the other is to disassemble the motor and send it to a repair shop for baking in a large drying room. Both methods require a lot of time and labor costs, and are very wasteful in terms of energy consumption, which is not economical or environmentally friendly.

[0003] A Chinese patent with announcement number 202222115055.X discloses a device for quickly restoring insulation of a large motor, including a rectifier, which includes three groups of thyristor rectifier bridges, each group of thyristor rectifier bridges including a coil and 4 thyristors, the anode of the first thyristor is connected to the cathode of the second thyristor, the anode of the third thyristor is connected to the cathode of the fourth thyristor, the cathode of the first thyristor is connected to the cathode of the third thyristor, the anode of the second thyristor is connected to the anode of the fourth thyristor, one end of the coil is connected to the anode of the first thyristor, and the other end is connected to the anode of the third thyristor; the anode of the second thyristor of the first group of thyristor rectifier bridges is connected to the cathode of the first thyristor of the second group of thyristor rectifier bridges, and the anode of the second thyristor of the second group of thyristor rectifier bridges is connected to the cathode of the first thyristor of the third group of thyristor rectifier bridges. The utility model adopts the technical method of directly passing low voltage and high current through the stator coil, so that the stator coil is directly heated and the insulation resistance is quickly restored from the inside out.

[0004] The device only energizes the motor stator to generate heat, has low heating efficiency, and lacks the functions of real-time monitoring of the heating circuit and automatic power on and off, which poses certain risks in practical applications. Summary of the invention

[0005] The purpose of the present invention is to provide a high-voltage motor winding automatic heating insulation recovery device and an operating method, through which the current passed into the motor winding is automatically controlled, and the stall effect of the motor and the thermal effect of the current are utilized, and detection sensors are set to monitor the key parameters of the motor winding in real time, and the heating circuit is automatically controlled by a PLC logic operation controller, so as to quickly, efficiently, environmentally friendly and safely improve the winding insulation of the high-voltage motor, thereby solving the problems raised in the above-mentioned background technology.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] A high-voltage motor winding automatic heating insulation recovery device comprises an insulation recovery system and an installation cabinet for accommodating the insulation recovery system, wherein the insulation recovery system comprises: a detection sensor for real-time monitoring of various key parameters of the motor winding during heating, and sending the collected monitoring signals to a PLC logic operation controller; a human-machine interaction device for an operator to set various parameters required for heating the motor winding, and to display in real time the operating information of the detection sensor and the PLC logic operation controller and the heating information of the motor winding; the PLC logic operation controller for calculating and analyzing the received monitoring signals, and outputting control signals to an actuator; an actuator for controlling the opening and closing of a main heating circuit of the motor winding; and a power supply mechanism for providing power to the operation detection sensor, the human-machine interaction device, the PLC logic operation controller, the actuator and the heating motor winding.

[0008] Preferably, the detection sensor includes a current transformer, a current transmitter, a temperature sensor and an A / D conversion module, the current transformer is used to monitor the current changes in the heating circuit, the current transmitter is used to convert the measured current into a standard signal output, the temperature sensor is used to monitor the temperature of the heating motor winding, and the A / D conversion module is used to convert analog signals such as current, voltage and temperature into digital signals that can be recognized by the PLC logic operation controller.

[0009] Preferably, the actuator includes an automatic air switch and an intermediate relay, the intermediate relay is used to control the opening and closing of the automatic air switch, the automatic air switch is used to control the closing and opening of the heating main circuit, and the intermediate relay is electrically connected to the PLC logic operation controller.

[0010] Preferably, the power supply mechanism includes a 380V three-phase AC power supply, a 380V / 220V transformer and an AC220V / DC24V DC power supply. The 380V three-phase AC power supply is used to provide a power source for the heating main circuit, the 380V / 220V transformer is used to convert the voltage of the 380V three-phase AC power supply into a 220V control power supply, and the AC220V / DC24V DC power supply is used to power current transmitters, temperature sensors, A / D conversion modules, human-computer interaction equipment, PLC logic operation controllers and intermediate relays.

[0011] An operating method of a high-voltage motor winding automatic heating insulation recovery device is implemented based on a high-voltage motor winding automatic heating insulation recovery device, comprising the following steps:

[0012] Step 1: Choose a suitable location and place the cabinet stably;

[0013] Step 2: Remove the motor air cooler, remove the windshields on both sides of the motor, and remove the heater covers on both sides;

[0014] Step 3: Equip two 50 square millimeter three-core copper cables, a 2500V megohmmeter, a clamp ammeter, and an infrared thermometer. Before supplying power, confirm that the power cable is in good condition and the terminal connection is tight, and confirm that the motor insulation is not less than 0.5M;

[0015] Step 4: Set up the temperature sensor, align the temperature sensing probe with the upper part of the motor stator winding, set the current, temperature and other operating parameters on the human-machine interaction device, confirm that all parameter settings are completed, and start the insulation recovery system through the human-machine interaction device after checking that they are correct;

[0016] Step 5: Within half an hour after power is supplied, someone must be assigned to monitor the operation of the equipment to confirm whether the displayed current and temperature values ​​are consistent with the results measured by the clamp ammeter and the temperature gun;

[0017] Step 6: Turn off the power 4 hours after powering on to check the insulation status, then turn on the power again for 4 hours. After the insulation is qualified, disconnect the heating circuit.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] 1. The present invention utilizes the motor stall effect and the current thermal effect, passes current through the motor stator winding to make it heat up, and stalls the rotor. After the rotor winding is stalled, a stall current is generated to make the rotor heat up, so that the heating efficiency is higher, the drying speed and the insulation recovery speed are faster, the motor can be put into operation as soon as possible to reduce the impact on production, and the labor cost of the motor insulation treatment work and the cost of sending the motor for maintenance are reduced.

[0020] 2. The present invention uses a PLC logic operation controller + touch screen control method to enable the entire device to automatically operate according to the set parameters, which saves human resources and facilitates the setting and monitoring of operating parameters.

[0021] 3. The present invention sets independent automatic control logic and manual control logic in the PLC logic operation controller. When one of the control logics fails, the other can continue to implement the control function, ensuring the reliability of the overall system control. A protection program is written. When the current or temperature value exceeds the set limit, the protection program is directly triggered to drive the intermediate relay to trip the automatic air switch. An emergency stop button is provided on the installation cabinet. In an emergency, pressing the emergency stop button can quickly cut off the power supply to ensure safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is the automatic heating control logic diagram of the present invention;

[0023] Figure 2It is the motor temperature rise monitoring diagram (℃ / t) of the present invention;

[0024] Figure 3 The motor insulation resistance measurement diagram (MΩ / t) of the present invention;

[0025] Figure 4 It is the motor main circuit current measurement diagram (A / t) of the present invention;

[0026] Figure 5 It is the wiring diagram of the primary equipment of the present invention;

[0027] Figure 6 A secondary circuit diagram of a current transformer for the stator current of a motor of the present invention;

[0028] Figure 7 A wiring diagram for connecting power supplies to various devices in the device of the present invention;

[0029] Figure 8 It is the wiring diagram of the PLC logic operation controller of the present invention;

[0030] Fig. 9 The electrical control principle diagram of the automatic air switch of the present invention;

[0031] Fig.10 A contact closure diagram of the transfer switch of the present invention;

[0032] Fig.11 A diagram of all signals received by the PLC logic operation controller of the present invention. DETAILED DESCRIPTION

[0033] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0034] In order to solve the problem that in the prior art, only the motor stator is powered on for heating, the heating efficiency is low, and there is a lack of real-time monitoring of the heating circuit and the function of automatic power on and off, this embodiment provides the following technical solutions:

[0035] See also Figure 1, a high-voltage motor winding automatic heating insulation recovery device, including an insulation recovery system and an installation cabinet for accommodating the insulation recovery system, the insulation recovery system including: a detection sensor, used to monitor various key parameters of the motor winding during heating in real time, and send the collected monitoring signals to a PLC logic operation controller; a human-machine interaction device, using a touch screen as a human-machine interaction device, the touch screen is arranged on the cabinet door of the installation cabinet, and is used by an operator to set various parameters required for heating the motor winding, and to display in real time the operation information of the detection sensor and the PLC logic operation controller and the heating information of the motor winding, such as the position of the automatic air switch, the working current, the motor temperature and the alarm information; the PLC logic operation controller is used to calculate and analyze the received monitoring signal, and output a control signal to the actuator; the actuator is used to control the opening and closing of the motor winding heating main circuit; the power supply mechanism is used to provide power for the operation detection sensor, the human-machine interaction device, the PLC logic operation controller, the actuator and the heating motor winding.

[0036] The PLC logic operation controller is equipped with automatic control logic and manual control logic. The two control modes are independent of each other. Therefore, when one of the control logics fails, the other can continue to realize the control function to ensure the reliability of the overall system control. In addition to the overcurrent release protection of the automatic air switch itself, a protection program is written in the PLC logic operation controller. When the current or temperature value exceeds the set limit, the protection program is directly triggered to operate, and a 24V control signal is output to drive the intermediate relay to trip the automatic air switch. In addition, an emergency stop button is also installed on the installation cabinet. In an emergency, whether the device is in automatic control mode or manual control mode, pressing the emergency stop button can quickly cut off the power supply to ensure safety.

[0037] The detection sensors include current transformers, current transmitters, temperature sensors and A / D conversion modules. The current transformers are used to monitor current changes in the heating circuit. The current transmitters are used to convert the measured current into standard signal outputs. The temperature sensors are used to monitor the temperature of the heating motor windings. The A / D conversion modules are used to convert analog signals such as current, voltage and temperature into digital signals that can be recognized by the PLC logic operation controller.

[0038] The actuator includes an automatic air switch and an intermediate relay. The intermediate relay is used to control the opening and closing of the automatic air switch. The automatic air switch is used to control the closing and opening of the heating main circuit. The intermediate relay is electrically connected to the PLC logic operation controller. The PLC logic operation controller can output a DC 24V control signal to control the intermediate relay to trip the automatic air switch.

[0039] The power supply mechanism includes a 380V three-phase AC power supply, a 380V / 220V transformer and an AC220V / DC24V DC power supply. Taking into account that there are multiple components of different voltage levels in this device, in order to facilitate external wiring, simplify the wiring and increase the on-site adaptability of the device, a large-capacity 380V three-phase AC power supply is directly introduced to provide the power source for the heating main circuit. The 380V / 220V transformer is used to convert the voltage of the 380V three-phase AC power supply into a 220V control power supply. The AC220V / DC24V DC power supply is used to power the current transmitter, temperature sensor, A / D conversion module, human-computer interaction equipment, PLC logic operation controller and intermediate relay.

[0040] An operating method of a high-voltage motor winding automatic heating insulation recovery device is implemented based on a high-voltage motor winding automatic heating insulation recovery device, comprising the following steps:

[0041] Step 1: Choose a suitable location and place the cabinet stably;

[0042] Step 2: Remove the motor air cooler, remove the windshields on both sides of the motor, and remove the heater covers on both sides;

[0043] Step 3: Equip two 50 square millimeter three-core copper cables, a 2500V megohmmeter, a clamp ammeter, and an infrared thermometer. Before supplying power, confirm that the power cable is in good condition and the terminal connection is tight, and confirm that the motor insulation is not less than 0.5M;

[0044] Step 4: Set up the temperature sensor, align the temperature sensing probe with the upper part of the motor stator winding, set the current, temperature and other operating parameters on the human-machine interaction device, confirm that all parameter settings are completed, and start the insulation recovery system through the human-machine interaction device after checking that they are correct;

[0045] Step 5: Within half an hour after power is supplied, someone must be assigned to monitor the operation of the equipment to confirm whether the displayed current and temperature values ​​are consistent with the results measured by the clamp ammeter and the temperature gun;

[0046] Step 6: Turn off the power 4 hours after powering on to check the insulation status, then turn on the power again for 4 hours. After the insulation is qualified, disconnect the heating circuit.

[0047] See also Figure 2-4 The implementation is further described in detail by describing a specific example:

[0048] The insulation level of the No. 5 pump motor has decreased, resulting in the motor insulation level failing to meet the equipment operation requirements, making the pump system unable to operate stably and reliably. Therefore, this insulation restoration system is used to restore its insulation. The steps are as follows:

[0049] 1. After the feed pump stops operating, enter the maintenance site, disconnect the feed pump from the motor, remove the primary incoming cable of the motor, and ensure that the system is isolated during maintenance to ensure safety.

[0050] 2. The insulation value of the motor winding measured by a 2500V megger is 1.9MΩ>0.5MΩ, which meets the safe use conditions of the insulation recovery device.

[0051] 3. Remove the air cooler of the motor, remove the windshields on both sides of the motor, and remove the heater covers on both sides to facilitate heat dissipation during the subsequent motor insulation recovery process and remove moisture and humidity attached to the inside of the motor.

[0052] 4. Choose a flat and suitable location to place the installation cabinet stably. The placement should be convenient for wiring and test personnel to operate.

[0053] 5. According to the stall principle and the parameters on the motor nameplate, it is roughly calculated that the main circuit working current of the device is about 100 amperes when it is working. Taking into account the 1.5 times safety margin, a maintenance power supply rated at 150A is selected on site as the power supply line of the device.

[0054] 6. According to the calculated working current of the device, select two 50 square millimeter three-core copper power cables to tightly connect the maintenance power supply to the device and the device to the motor winding to prevent heat generation due to loose connection and cause danger.

[0055] 7. Set up the temperature sensor for collecting the temperature of the motor winding and align it with the upper part of the motor stator winding so as to accurately collect the maximum temperature of the motor winding.

[0056] 8. Confirm that all wiring has been completed, the wiring connections are tight and in good contact; after confirming that the status of each component inside the device is correct, supply power to the entire device.

[0057] 9. After power-on, set the current and temperature control parameters on the touch screen. Because the No. 5 pump motor is Class B insulation, the performance reference temperature is 100°C, combined with the previously calculated working current of 100A, set the temperature upper limit to 90°C and the current upper limit to 110A.

[0058] 10. After all parameters are set, check all wiring conditions and device status again. After confirming that everything is normal, press the start button on the touch screen. At this time, the intermediate relay drives the automatic air switch to close, the heating main circuit is connected, and the motor insulation restoration operation begins.

[0059] 11. After the main circuit is connected, use a clamp ammeter and a temperature gun to review the sampling values ​​of the detection element. The values ​​of the two should be approximately equal to ensure the correctness of the sampling values ​​and avoid equipment failure and damage due to measurement errors.

[0060] 12. Manually stop and measure the insulation resistance of the motor every 30 minutes, and record the temperature and current sampling values ​​at the same time, so as to draw charts to analyze the operating status of the device and the recovery of the motor insulation.

[0061] 13. Wait until the motor insulation value returns to a stable state and no longer increases and lasts for 1 hour, then stop the device and cut off the power.

[0062] 14. Reinstall the motor after insulation restoration and restore it to the state before the No. 5 pump was shut down. The motor insulation restoration work is completed.

[0063] 15. Draw the following chart based on the collected data.

[0064] After analysis, it was found that in the initial stage, the moisture inside the insulating material formed moisture when heated and diffused outward, filling the motor chamber. When it adhered to the surface of the insulating material, the insulation resistance decreased. After that, the moisture in the insulating material and the chamber was gradually expelled, and the insulation resistance value rebounded until it stabilized, achieving the expected effect. At the same time, the current and temperature values ​​were always within a reasonable range, verifying the safety and reliability of the automatic device.

[0065] See also Figure 5 , the primary equipment wiring adopts 380V AC as the total input power;

[0066] L1, L2, L3, represents the A, B, C phase sequence of the three alternating currents;

[0067] QL is the code name of the automatic air switch, which is the main automatic actuator of this device. It automatically connects and disconnects the connection between the 380V power supply and the motor by receiving the voltage signal generated by the closing of the output node of the PLC.

[0068] M3~ indicates a three-phase AC motor, UVW is the terminal code of the motor;

[0069] PE is the grounding wire of the motor casing;

[0070] TA is a small through-type current transformer used to collect the current in the motor stator when the device is running;

[0071] AX is the terminal number of the high-voltage side of the control transformer, and ax is the terminal number of the low-voltage side of the control transformer;

[0072] QF1 and QF2 are small air switches. QF1 is responsible for connecting and disconnecting L1, L2 is connected to the AX terminal on the high-voltage side of the control transformer, and QF2 is responsible for connecting and disconnecting the connection between the ax terminal on the low-voltage side of the transformer and the control circuit.

[0073] L, N represent the phase and neutral lines of single-phase 220V AC.

[0074] Note: The purpose of using a control transformer here is to conveniently convert 380V AC power into 220V AC power to supply the control circuit of this device. Because the on-site conditions of some equipment are complicated and it is sometimes difficult to directly obtain 220V AC power, installing a control transformer can conveniently solve this problem, and at the same time simplify the external wiring and improve efficiency.

[0075] See also Figure 6 , the secondary circuit of the current transformer for measuring the stator current of the motor: 1TA is the code for the current transformer; V411 and N411 are the codes for the secondary terminals of the current transformer; AF is the current transmitter, 6 and 8 are its input terminal numbers, and its function is to convert the large current collected by the current transformer into a small current signal of 4 to 20ma for reading by the analog module of the PLC.

[0076] See also Figure 7 , the power connection wiring of each device in the device: AF represents the current transmitter, 1 and 2 are its external 220V power supply terminals.

[0077] U stands for switching power supply, which is a device that converts 220V AC into 24V DC. L and N are the letter symbols of the 220V input phase line and neutral line respectively, and V+ and V- are the 24V output terminal labels of the switching power supply.

[0078] The input 220V voltage of the current transmitter AF and the switching power supply U both come from the output end of the control transformer of the device.

[0079] HMI is the representative letter of the touch screen, + and - represent its power input terminals;

[0080] PLC is the English abbreviation of programmable logic controller, L+, M is its power input terminal;

[0081] BT is the representative letter of the temperature sensor, and red and black are the colors of its power connection wires;

[0082] The power supply of HMI, PLC and BT is taken from the 24V output terminal of the switching power supply U.

[0083] See also Figure 8 , Wiring between PLC logic operation controller and associated equipment:

[0084] S7200CPU226DC / DC / DC is a PLC model. Its function is to read the input signal, and then select the output after the logic operation through the internal user-defined program.

[0085] EM235 is the model of PLC analog module. Its function is to convert the 4-20MA analog current signal output by the current transmitter and temperature sensor into a digital signal recognizable by PLC, and transmit it to the PLC for logic operation.

[0086] KA1 and KA2 are coils of intermediate relays, KA1 represents the closing intermediate relay coil, and KA2 represents the opening intermediate relay coil. Their driving voltage is 24V DC, which matches the output terminal voltage of the PLC and can be directly connected in series in the output circuit of the PLC. At the same time, since the coil of the intermediate relay is an inductive load, in order to prevent the reverse overvoltage generated by the ordinary on-off inductive load from damaging the output terminal of the PLC, a freewheeling diode is specially connected in reverse parallel to each coil to eliminate the reverse overvoltage hazard of the coil.

[0087] DC24V means that this model PLC adopts DC 24V power supply, V+, V-, A01, A02, B01, B02 are terminal numbers;

[0088] KA3 is the normally open auxiliary contact of the fault auxiliary intermediate relay of the automatic air switch. Its function is that when a fault occurs inside the automatic air switch QL, the QL auxiliary contact connected in series with the KA3 relay coil is closed, the KA3 coil is energized and attracted, and the KA3 auxiliary normally open contact will also be closed. At this time, the input end of the PLC will receive a valid high-level signal, thereby judging that the automatic air switch QL has a fault. Then, after the PLC program calculation, the output end of the closing coil KA2 will be locked in the internal logic of the PLC. At this time, the automatic air switch QL will not be able to close, thereby realizing the function of preventing continued closing when QL fails, causing the fault to expand and damage the equipment.

[0089] SV is the abbreviation of transfer switch. Figure 4 The middle refers to one pair of normally open auxiliary contacts of the transfer switch. Here, it plays the role of switching the operation mode. When the handle of the SV is turned to the automatic position, the SV auxiliary normally open contact in the figure will be closed, and the whole device will enter the automatic operation state;

[0090] QL is the abbreviation of automatic air switch. Figure 4 The middle refers to its pair of normally open contacts and a pair of normally closed contacts. Their function is that when QL is in the closed state, the normally open auxiliary contacts of QL are closed, and the PLC can receive the closed signal of QL. Conversely, when QL is in the open state, the normally closed auxiliary contacts of QL are closed, and the PLC can receive the open signal of QL. Thus, the PLC can judge the current open and closed state of the automatic switch QL;

[0091] The current 4~20MA signal reflects the real-time current in the motor stator coil when the device is running. When this current is greater than the allowable value set in the PLC program, the PLC will issue a trip command to close the trip relay KA2, thereby connecting the QL trip circuit, causing it to trip and cut off the connection between the main power supply and the motor stator coil to ensure safety.

[0092] The temperature 4~20MA signal feedback is the real-time maximum temperature of the motor stator winding when the automatic device is running, which is collected by the infrared temperature sensor installed on the upper part of the motor stator winding. After the PLC collects this temperature, it compares it with the temperature value set in our program. When it is lower than the limit, it issues a closing command to make the KA1 coil energized and attracted, thereby connecting the closing circuit of QL.

[0093] When the temperature value is higher than the limit, a trip command is issued to energize the KA2 coil, thereby connecting the QL trip circuit. In this way, the entire device can be automatically operated.

[0094] See also Fig. 9 , the electrical control principle of automatic air switch QL is as follows:

[0095] QF2 (small air switch); SV (conversion switch); SB (emergency stop button); KA1 (normally open auxiliary contact of automatic closing relay); KA2 (normally open auxiliary contact of automatic opening relay); QL (automatic air switch); A1 (common end of QL closing and opening control coil); A2 (input end of QL closing control coil); A4 (input end of QL opening control coil) B2, B4, 81, 82, 84 (QL multifunctional auxiliary contacts, of which 81 and 84 are a pair of normally open auxiliary contacts that will only close when QL fails)

[0096] KA3 (fault auxiliary intermediate relay) When QL itself has a fault, the KA3 coil is energized and the normally open auxiliary contact of KA3 is closed.

[0097] When the small air switch QF2 is closed, the QL control circuit is connected to the power supply. Line #1 is energized, and line #2 is energized. There are two control modes to choose from:

[0098] 1. Automatic control: Turn the switch SV to automatic, then the 5 and 6 terminals of SV are connected, the #4 line is energized, and then press the start button on the HMI (touch screen), the PLC will enter the automatic operation mode, when the temperature 4~20MA signal collected by the PLC is lower than the minimum value set by the program, it will output a valid high level to make Figure 4 KA1 (closing relay coil) is energized and closes. Figure 5The auxiliary normally open contact of KA1 will also close. Then A2 (QL closing control coil input terminal) is energized, and the QL closing circuit is fully connected. Then the QL closing coil operates to close QL and connect the main power supply and the motor. The stator winding of the motor is energized, and the thermal effect of the current and the principle of motor stalling are used to directly heat the winding to achieve the purpose of improving the insulation of the motor stator winding. As the heating continues, the temperature will get higher and higher. The infrared temperature sensor installed on the upper part of the stator winding will collect the temperature value in real time and upload it to the PLC for logical operation. When the collected temperature value exceeds the maximum allowable temperature set by the program (excessive temperature will cause serious damage to the stator winding of the motor), the PLC will output a valid high level to make Figure 4 KA2 (opening relay coil) is energized and closes. Figure 5 The auxiliary normally open contact of KA2 will also close. Then A4 (QL opening control coil input terminal) is energized, and the QL opening circuit is fully connected. Then the QL opening coil operates to open QL, disconnecting the main power supply and the motor. The thermal effect of the motor stator coil de-energized current and the principle of stalling stop the motor stator coil temperature to stop rising immediately, and its temperature will begin to drop over time. When its temperature drops below the minimum limit, the PLC continues to connect the QL closing circuit... Repeatedly, the automatic control function of this device is realized.

[0099] 2. Manual control:

[0100] Manual closing: Turn the transfer switch SV to the manual closing position. At this time, the 1 and 2 terminals of SV are connected, A2 (QL closing control coil input terminal) is directly energized without PLC control, the QL closing circuit is fully connected, and then the QL closing coil operates to close QL, connecting the main power supply and the motor. The manual closing function of this device is realized.

[0101] Manual opening: Turn the transfer switch SV to the manual opening position. At this time, the 11 and 12 terminals of SV are connected, A4 (QL opening control coil input terminal) is directly energized without PLC control, the QL opening circuit is fully connected, and then the QL opening coil operates to open QL, disconnecting the main power supply and the motor. The manual opening function of this device is realized.

[0102] 3. Emergency stop:

[0103] For safety reasons, in addition to designing two control systems, an emergency stop button (SB3) is also installed separately. When an emergency occurs, just press the red emergency stop button (SB3) set on the control box door to directly energize A4 (QL trip control coil input terminal) without PLC control, and the QL trip circuit is fully connected. Then the QL trip coil is activated to trip QL and disconnect the main power supply and the motor.

[0104] See also Fig.10 , contact closure table of SV (transfer switch), LW12-46D049.4040.4 is its model.

[0105] When it is turned to the hand-on position, the 1 and 2 contacts of SV are connected;

[0106] When it is turned to the hand jump position, the SV's 11 and 12 contacts are connected;

[0107] When rotated to the PLC position, contacts 5, 6 and 7, 8 of SV are connected.

[0108] See also Fig.11 It is all the signals transmitted from the electrical equipment in the whole device to the PLC logic operation controller, which are concentrated on one diagram for easy viewing and wiring.

[0109] A01, A02, B01, B02, D01, D02, D03, D04, D05 are all terminal numbers. The corresponding relationships in different diagrams are convenient for understanding and wiring.

[0110] AF 4, 5 indicates the No. 4 and No. 5 terminals of the current transmitter.

[0111] BT blue, orange indicates the blue and orange insulated secondary 4-20MA output wires of the infrared temperature sensor.

[0112] SV7, 8 means that contacts 7 and 8 of SV are connected when the whole device is under PLC automatic control.

[0113] QL closed position, when QL is in the closed state, the normally open contact is connected; QL open position, when QL is in the open state, the normally open contact is connected. Their function is to provide the PLC with the closed and open position signals of QL, so that it can be conveniently and intuitively displayed on the HMI (touch screen) for operators to view.

[0114] KA3 is the normally open auxiliary contact of the fault auxiliary intermediate relay. When QL itself fails, it is connected and transmits the QL fault information to the PLC to facilitate the PLC to make logical judgments and thus lock the automatic closing function to prevent the fault from expanding.

[0115] Working principle: This device uses the motor's locked-rotor principle and the thermal effect of current. Under the control of the PLC logic operation controller, low-voltage current is passed through the motor's stator winding, and the motor's rotor is locked to generate a locked-rotor current, which converts the electrical energy in the stator and rotor into thermal energy. The temperature generated by the motor itself is used to dry the motor, thereby restoring the motor's insulation to normal.

[0116] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0117] While the embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that many changes, modifications, substitutions and variations can be made to the embodiments without departing from the principles and spirit of the invention.

Claims

1. A high-voltage motor winding automatic heating insulation recovery device, comprising an insulation recovery system and an installation cabinet for accommodating the insulation recovery system, characterized in that: The insulation restoration system comprises: Detection sensor, used to monitor various key parameters of the motor winding during heating in real time, and send the collected monitoring signals to the PLC logic operation controller; Human-machine interaction equipment, used by operators to set various parameters required for heating the motor windings, and to display the operation information of the detection sensor, PLC logic operation controller and the heating information of the motor windings in real time; PLC logic operation controller, used to calculate and analyze the received monitoring signals and output control signals to the actuators; Actuator, used to control the opening and closing of the main circuit for heating the motor winding; The power supply mechanism is used to provide power to the operation detection sensor, human-machine interaction equipment, PLC logic operation controller, actuator and heating motor winding.

2. The high-voltage motor winding automatic heating insulation recovery device according to claim 1 is characterized in that: The detection sensor includes a current transformer, a current transmitter, a temperature sensor and an A / D conversion module. The current transformer is used to monitor the current changes in the heating circuit, the current transmitter is used to convert the measured current into a standard signal output, the temperature sensor is used to monitor the temperature of the heating motor winding, and the A / D conversion module is used to convert analog signals such as current, voltage and temperature into digital signals that can be recognized by the PLC logic operation controller.

3. The high-voltage motor winding automatic heating insulation recovery device according to claim 1 is characterized in that: The actuator includes an automatic air switch and an intermediate relay. The intermediate relay is used to control the opening and closing of the automatic air switch. The automatic air switch is used to control the closing and opening of the heating main circuit. The intermediate relay is electrically connected to the PLC logic operation controller.

4. The high-voltage motor winding automatic heating insulation recovery device according to claim 1 is characterized in that: The power supply mechanism includes a 380V three-phase AC power supply, a 380V / 220V transformer and an AC220V / DC24V DC power supply. The 380V three-phase AC power supply is used to provide a power source for the heating main circuit. The 380V / 220V transformer is used to convert the voltage of the 380V three-phase AC power supply into a 220V control power supply. The AC220V / DC24V DC power supply is used to power current transmitters, temperature sensors, A / D conversion modules, human-computer interaction equipment, PLC logic operation controllers and intermediate relays.

5. An operating method of a high-voltage motor winding automatic heating insulation recovery device, based on a high-voltage motor winding automatic heating insulation recovery device according to any one of claims 1 to 4, characterized in that: The following steps are involved: Step 1: Choose a suitable location and place the cabinet stably; Step 2: Remove the motor air cooler, remove the windshields on both sides of the motor, and remove the heater covers on both sides; Step 3: Equip two 50 square millimeter three-core copper cables, a 2500V megohmmeter, a clamp ammeter, and an infrared thermometer. Before powering on, confirm that the power cable is in good condition and the terminal connection is tight, and confirm that the motor insulation is not less than 0.5M; Step 4: Set up the temperature sensor, align the temperature sensing probe with the upper part of the motor stator winding, set the current, temperature and other operating parameters on the human-machine interaction device, confirm that all parameter settings are completed, and start the insulation recovery system through the human-machine interaction device after checking that they are correct; Step 5: Send someone to monitor the operation of the equipment within half an hour after power is supplied to confirm whether the displayed current and temperature values ​​are consistent with the results measured by the clamp ammeter and the temperature gun; Step 6: Turn off the power 4 hours after powering on to check the insulation status, then turn on the power again for 4 hours. After the insulation is qualified, disconnect the heating circuit.

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