Disclosure of Invention
The present invention is directed to a low-frequency heating power supply system for a three-phase integrated power transformer and an operating method thereof, which are used to solve one or more of the above technical problems. The invention can greatly reduce the electric quantity consumed by the heating capacity of the power supply and can improve the heat dissipation efficiency; the damage of the core components of the power supply system caused by the electric spark generated in the power supply system can be prevented.
In order to achieve the purpose, the invention adopts the following technical scheme:
the invention discloses a low-frequency heating power supply system of a three-phase integrated power transformer, which comprises:
the incoming line breaker is used for realizing the input and cut-off operation of an input power supply;
the incoming line contactor and the outgoing line contactor are used for realizing the remote on-off operation of the power supply of the whole machine;
the phase-shifting transformer is used for realizing the boosting of the input power supply and the formation of the multi-pulse rectification input power supply;
the low-frequency inverter comprises a plurality of groups of power units and is used for realizing three-phase low-frequency output;
the automatic power-off system is used for realizing automatic power-off when the temperature is too high or a circuit connecting line has a fault, and protecting the whole low-frequency heating power supply system;
and the control system is used for realizing the control of the on-off of the incoming line breaker, the incoming line contactor, the outgoing line contactor, the phase-shifting transformer and the low-frequency inverter.
A further improvement of the invention is that the automatic power-off system comprises: a chassis;
an upper cover is fixedly arranged at the upper end of the case;
a perspective window is fixedly arranged on the side wall of the case;
the two opposite ends of the case are respectively provided with a vent and an air outlet;
the inner cavity of the case is divided into a plurality of mounting areas by a first partition plate and a second partition plate; the first partition plate is provided with a ventilation groove and a ventilation hole, and the second partition plate is provided with a ventilation groove and a ventilation hole; the inner wall of the through-line groove is fixedly connected with a partition panel, the partition panel is provided with a movable groove, the partition panel is fixedly connected with a U-shaped column, two ends of the U-shaped column are fixedly connected with connecting lines, one end of the U-shaped column is arranged in the movable groove, the inner wall of the movable groove is provided with a sliding groove, the inner wall of the lower end of the movable groove is fixedly connected with a thermal expansion pipe, the upper end of the thermal expansion pipe is movably connected with a connecting sheet, and two ends of the connecting sheet are arranged in the sliding groove;
one end of the case close to the shielding plate is fixedly connected with a rotating shaft, and the outer wall of the rotating shaft is movably connected with a rotating drum for winding the connecting wire;
the upper ends of the first partition plate and the second partition plate are provided with baffle plates for sealing other installation areas except the installation area where the rotary drum is located.
The invention has the further improvement that the inner wall of one end of the ventilation opening, which is far away from the case, is fixedly connected with a screen and absorbent cotton; one end of the ventilation opening close to the case is fixedly connected with a fan; wherein the absorbent cotton is arranged between the screen and the fan;
the air outlet is provided with a shielding plate and an isolation net, the shielding plate is used for preventing rainwater from entering the case, and the isolation net is used for preventing external suspended particles or impurities from entering the case from the air outlet.
The invention is further improved in that one end of the rotary drum close to the shielding plate is fixedly connected with an arc-shaped block for rotating the rotary drum to shrink the connecting line.
The invention has the further improvement that the side walls of the first clapboard and the second clapboard are fixedly connected with mounting blocks; the mounting block is provided with a fixing hole.
A further development of the invention is that the control system comprises: the card inserting machine comprises a card inserting machine box, a patch panel, a sampling panel, a relay panel, a fan control panel and a touch screen;
the card insertion chassis includes: the digital board, the analog board, the optical fiber board, the power supply board and the motherboard;
the adapter plate is used for the adapter of the card-inserting case and other electrical elements; all switch signals are transmitted to the digital board through the cable after being connected to the adapter board, and all analog input signals are transmitted to the analog board through the cable after being connected to the adapter board;
the sampling plate is used for monitoring the voltage of the incoming line breaker;
the relay board is used for controlling coil voltages of a pre-charging contactor, a closing contactor and an output contactor in the power supply cabinet, controlling the on-off of contacts of the pre-charging contactor, the closing contactor and the output contactor, and controlling an audible and visual alarm;
the fan control board is used for controlling a three-phase alternating current fan used in the power supply cabinet;
the touch screen is used for displaying a control interface and realizing manual control.
A further improvement of the invention is that the digital board comprises: a switch input interface and a switch output interface; the two interfaces are respectively connected with the adapter plate through cables and are used for controlling the on-off of the incoming line breaker and collecting feedback signals of the contacts of the acquisition plate.
The invention has the further improvement that the analog board adopts a high-speed DSP chip and is used for processing big data in real time and calculating voltage, current, power, resistance and frequency parameters;
the input interface of the analog board is connected with the adapter board through a cable and is used for transmitting analog signals collected by the voltage and current sensors from the sampling board;
the simulation board exchanges data with the touch screen through an RS232 communication interface, is used for displaying state parameters of the power supply and receiving parameter setting of the touch screen;
the simulation board exchanges data with the upper computer through the RS485 communication interface, is used for providing state parameters of a power supply and receiving parameter setting of the upper computer.
The invention has the further improvement that the optical fiber plate carries out data transmission with the power unit through optical fibers, and is used for periodically sending pulse width modulation signals to the power unit and receiving information collected by the power unit; the method is used for receiving a blocking signal sent by a power unit when the power unit fails;
the power panel is used for providing direct current power for each circuit board in the card insertion case;
the mother board is connected with other boards through the card inserting case and used for realizing electrical connection of the boards.
The invention discloses an operation method of a low-frequency heating power supply system of a three-phase integrated power transformer, which comprises the following steps of:
the input and cut-off operation of an input power supply is realized through an incoming line breaker;
the remote on-off operation of the power supply of the whole machine is realized through the incoming line contactor and the outgoing line contactor;
the boosting of an input power supply and the formation of a multi-pulse rectification input power supply are realized through a phase-shifting transformer;
three-phase low-frequency output is realized through a low-frequency inverter; the sign page comprises a plurality of groups of power units;
the automatic power-off system is used for realizing automatic power-off when the temperature is too high or a circuit connecting line fails, so that the whole low-frequency heating power supply system is protected;
the control system realizes the control of the on-off of an incoming line breaker, the on-off of an incoming line contactor, the on-off of an outgoing line contactor, the on-off of a phase-shifting transformer and the on-off of a low-frequency inverter; and calculating to obtain the voltage, current, power, resistance and frequency parameters of each element.
Compared with the prior art, the invention has the following beneficial effects:
the system can greatly reduce the electric quantity consumed by the heating capacity of the power supply; the installation and maintenance are convenient; the damage of connecting wires in the power supply system or the influence on core components of the power supply system when electric sparks are generated can be prevented. The invention is provided with a low-frequency inverter, which can pressurize through terminals 1 and 2 of a primary winding of the transformer, short-circuit through terminals 3 and 4 of the secondary winding, realize the heating of the transformer by utilizing the heating of resistors R1 and R2 of the primary winding and the secondary winding, and simultaneously, the ratio of the resistors R1 and R2 of the transformer winding to the total impedance is 0.5 to 1.5 percent; z12 is mainly composed of inductive components, when the power frequency is reduced to 1% of the rated frequency, Z12 is reduced to about 1%, the applied voltage is greatly reduced under the same heating current, the output capacity of the heating power supply is reduced to about 1% of the power frequency power supply, and the electric quantity consumed by the heating capacity of the power supply can be greatly reduced; the installation and maintenance are convenient; the damage of connecting wires in the power supply system or the influence on core components of the power supply system when electric sparks are generated can be prevented.
In the invention, if the connecting wire in the power supply system is aged or generates electric spark after being used for a long time, the thermal expansion pipe expands at a higher temperature, so that the connecting sheet rises to break the connecting wire connected with the U-shaped column, thereby avoiding the damage of a mother board, a switching board, a sampling board and the like in the power supply system.
In the invention, if the connecting wire in the power supply system is aged or generates electric spark after long-time use, the high temperature expands the thermal expansion pipe, so that the connecting sheet is raised, the connecting wire connected with the U-shaped column is broken, and the damage of the power supply system is avoided.
According to the invention, the mounting areas are locally sealed through the baffle plates, so that air entering the ventilation openings passes through the ventilation grooves and the ventilation holes to enter each mounting area, and the heat dissipation efficiency can be improved.
According to the invention, the side walls of the first partition plate and the second partition plate are fixedly connected with the mounting blocks, and the mounting blocks are provided with fixing holes, so that a template, a transfer plate, a simulation plate and the like in a power supply system can be conveniently and fixedly mounted.
According to the invention, the control system comprises a card plug-in case, a switching board, a sampling board, a relay board, a fan control board and a touch screen, wherein the card plug-in case comprises a digital board, an analog board, an optical fiber board, a power board and a mother board, and is managed in a modularized manner, so that later maintenance is facilitated.
In the invention, the digital board comprises a switch input interface and a switch output interface, is connected with the adapter board through a cable and is used for controlling the on-off of the alternating current contactor and collecting a contact feedback signal of the alternating current contactor, an emergency stop switch and a switch signal of each button, thereby being convenient for mastering the information of a power supply system.
Detailed Description
The technical solution in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention; it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments, and all other embodiments obtained by those skilled in the art without any inventive work are within the scope of the present invention.
In the description of the present invention, it should be noted that the terms "upper", "lower", "inner", "outer", "top/bottom", and the like indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience of description and simplification of description, but do not indicate or imply that the referred device or element must have a specific orientation, be constructed in a specific orientation, and be operated, and thus should not be construed as limiting the present invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.
In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "disposed," "sleeved/connected," "connected," and the like are to be construed broadly, e.g., "connected," which may be fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.
Referring to fig. 1 to 10, a low-frequency heating power supply system of a three-phase integrated power transformer according to an embodiment of the invention includes: the system comprises an incoming line breaker, an incoming line contactor, an outgoing line contactor, a phase-shifting transformer, a low-frequency inverter, a control system and an automatic power-off system.
The incoming line breaker is used for input power supply switching-in and switching-off operation and short circuit protection in the case of load abnormal state.
The incoming line contactor and the outgoing line contactor are used for realizing remote on-off operation of the power supply of the whole machine.
The phase-shifting transformer is used for completing input power boosting and multi-pulse rectification input power formation.
The automatic power-off system is used for automatically powering off when the temperature is too high or a circuit connecting line fails, and protecting the whole low-frequency heating power supply system.
The low-frequency inverter part consists of a plurality of groups of power units and is used for finishing three-phase low-frequency output; the power unit is a general component, and is convenient for users to use and maintain.
Referring to fig. 1 to 4, an automatic power-off system according to an embodiment of the present invention includes: the device comprises a case 1, a first clapboard 8 and a second clapboard 9; the upper end of the case 1 is fixedly connected with an upper cover 2; the side wall of the case 1 is fixedly connected with a perspective window 3, one end of the case 1 is fixedly connected with a vent 4, the inner wall of one end, far away from the case 1, of the vent 4 is fixedly connected with a screen 5 and absorbent cotton 6, and one end, close to the case 1, of the vent 4 is fixedly connected with a fan 7; the water absorption cotton 6 is arranged between the screen 5 and the fan 7 and is used for preventing impurities from entering the power supply system and eliminating water entering the power supply system; the end of the case 1 far away from the vent 4 is fixedly connected with a shielding plate 21, the end of the case 1 near the shielding plate 21 is provided with an air outlet, and the air outlet is provided with an isolation net, so that the air entering from the vent 4 can be conveniently dispersed.
In the embodiment of the invention, the inner cavity of the case 1 is divided into seven installation areas by four first partition plates 8 and two second partition plates 9, the side walls of the first partition plates 8 and the second partition plates 9 are fixedly connected with installation blocks, and the installation blocks are provided with fixing holes, so that templates, adapter plates, simulation plates and the like in a fixed power supply system can be conveniently installed; the first partition plate 8 is provided with a ventilation groove 10 and a plurality of ventilation holes 18, and the second partition plate 9 is provided with a ventilation groove 11 and a ventilation hole 18; inner wall fixedly connected with partition panel 12 of through-wire groove 11, movable groove 14 has been seted up to partition panel 12, partition panel 12 fixedly connected with U type post 13, the both ends fixed connection connecting wire of U type post 13, and the one end of U type post 13 sets up in movable groove 14, spout 15 has been seted up to movable groove 14's inner wall, movable groove 14's lower extreme inner wall fixedly connected with thermal expansion pipe 16, thermal expansion pipe 16's material sets up to the fire-retardant rubber of thermal expansion, and thermal expansion pipe 16 packs has mercury, jack-up connection piece 17 when thermal expansion pipe 16 is heated, cut off the connecting wire of connecting on U type post 13, thermal expansion pipe 16's upper end swing joint has connection piece 17, the both ends of connection piece 17 set up in spout 15.
In the embodiment of the invention, one end of a case 1 close to a shielding plate 21 is fixedly connected with a rotating shaft 19, the outer wall of the rotating shaft 19 is movably connected with a rotating drum 20, one end of the rotating drum 20 close to the shielding plate 21 is fixedly connected with an arc-shaped block, so that the rotating drum 20 can be conveniently rotated to shrink a connecting line, the upper ends of a first partition plate 8 and a second partition plate 9 are provided with baffle plates 22, the length of the baffle plates 22 is equal to 4/5 of the length of the case 1, other installation areas except the installation area where the rotating drum 20 is arranged are partially sealed, and air entering from a ventilation opening passes through a ventilation groove and the ventilation opening to enter each installation area, so that the heat dissipation efficiency is improved.
In the embodiment of the invention, when the automatic power-off system is used, if a connecting line in a power supply system is aged or generates electric spark after being used for a long time, the thermal expansion pipe 16 expands at a higher temperature, so that the connecting sheet 17 rises to break the connecting line connected with the U-shaped column 13, and the damage to a motherboard, an adapter plate, a sampling plate and the like in the power supply system is avoided.
The power supply system of the embodiment of the invention has the following main technical indexes:
1. inputting the number of phases: triphase/50 Hz;
2. input voltage: AC 380V +/-10%;
3. output capacity: 870 kVA;
4. output phase number: three phases;
5. output voltage: 0-1 kV, and the zero start is continuously adjustable;
6. rated output current: 500A;
7. output frequency: the frequency of the signal is continuously adjustable from 0.01Hz to 1 Hz;
8. rated operating system: full load continuous operation;
9. temperature rise of the unit: tau max is less than or equal to 55K;
10. a cooling mode: forced air cooling;
11. working noise: less than or equal to 75dB (1 meter away from the body);
12. the control mode is as follows: the machine is provided with a machine body;
13. the communication mode is as follows: RS 485;
14. the installation mode is as follows: a container;
15. length width height: less than or equal to 6m by 2.4m by 2.6 m;
16. the working mode is as follows: constant current or constant voltage and constant temperature control;
17. protection design: wind prevention, dust prevention and sand flying prevention;
18. ambient temperature: -25 ℃ to +40 ℃;
19. altitude: less than or equal to 2000 m;
20. relative humidity: less than 95 percent and no condensation.
Referring to fig. 8 to 10, the control system according to the embodiment of the present invention includes: the card inserting machine comprises a card inserting machine box, a patch panel, a sampling panel, a relay panel, a fan control panel and a touch screen; the card insertion case includes: digital board, analog board, optic fibre board, power strip and mother board, the modularization management is convenient for later stage maintenance.
The digital board includes: the switch input interface and the switch output interface are connected with the adapter plate through cables and are used for controlling the on-off of the alternating current contactor, collecting contact feedback signals of the alternating current contactor, emergency stop switches and switch signals of all buttons, and information of a power supply system can be conveniently mastered.
The simulation board adopts a high-speed DSP chip and is used for processing a large amount of data in real time and calculating parameters such as voltage, current, power, resistance and frequency, wherein the simulation input interface is connected with the adapter board through a cable and is used for transmitting the voltage from the sampling board and analog signals collected by the current sensor, the simulation board performs data exchange with the touch screen through an RS232 communication interface, state parameters of a power supply are provided and are subjected to parameter setting of the touch screen, the simulation board performs data exchange with an upper computer through an RS485 communication interface, the state parameters of the power supply are provided and are subjected to parameter setting of the upper computer.
The optical fiber plate transmits data with the power unit through the optical fiber, periodically Sends Pulse Width Modulation (SPWM) signals to the power unit, receives information collected by the power unit, and sends blocking signals to the optical fiber plate when the power unit breaks down.
The power supply board is arranged to provide +3.3V, +5V, +12V, -12V direct current power for each circuit board in the card-inserting case.
The motherboard is connected to each of the other boards through the card-insertion chassis for each board to have a corresponding electrical connection.
The adapter plate is used for the switching of the card-inserting case and other electrical elements, the adapter plate does not have any control function, all switch signals are sent to the digital board through one cable after being connected to the adapter plate, and all analog input signals are sent to the analog board through the other cable after being connected to the adapter plate.
The relay board is used for controlling coil voltages of a pre-charging contactor, a closing contactor and an output contactor in the power cabinet, so that the on-off of contacts of the relay board is controlled, and the audible and visual alarm is controlled.
The fan control panel is used for the inside three-phase alternating current fan that uses of power cabinet.
The technical scheme of the embodiment of the invention greatly reduces the electric quantity consumed by the heating capacity of the power supply, is convenient to install and maintain, and prevents the damage of a connecting wire in the power supply system or the influence on the core component of the power supply system when electric spark occurs. The length of baffle equals 4/5 of quick-witted case length, carries out local seal to the installation region, makes the wind that the vent got into pass ventilation groove and ventilation hole and gets into each installation region, improves radiating efficiency. The equal fixedly connected with installation piece of lateral wall of first baffle and second baffle, the fixed orifices has been seted up to the installation piece, is convenient for install template, keysets and simulation board etc. among the fixed electrical power generating system. The control system comprises a card inserting case, a switching board, a sampling board, a relay board, a fan control board and a touch screen, wherein the card inserting case comprises a digital board, an analog board, an optical fiber board, a power board and a mother board, and is subjected to modular management and convenient later maintenance. The digital board comprises two interfaces of switch input and switch output, is connected with the adapter board through a cable and is used for controlling the on-off of the alternating current contactor, collecting contact feedback signals of the alternating current contactor, an emergency stop switch and switch signals of all buttons, and is convenient for mastering information of a power supply system.
Referring to fig. 5, the working principle of the low-frequency heating power supply is as follows: the power supply is switched by the incoming line breaker to complete overcurrent protection, then the power supply is sent to the incoming line contactor to complete remote power supply switching, after the power supply is boosted by the phase-shifting transformer, the low-frequency alternating current power supply is output by the inverter circuit, and the converted low-frequency power supply is used by the drying transformer.
Referring to fig. 6, when the transformer is heated, the terminals 1 and 2 of the primary winding of the transformer are pressurized, the terminals 3 and 4 of the secondary winding are shorted, and the heating of the primary and secondary winding resistors R1 and R2 is utilized to heat the transformer.
Because the voltage applied to the No. 1 and No. 2 terminals is very low when the No. 3 and No. 4 terminals of the transformer are in short circuit, the excitation branches Rm and Lm can be ignored.
In the embodiment of the invention, the terminals 1 and 2 of the primary winding of the transformer are pressurized, the terminals 3 and 4 of the secondary winding are short-circuited, the heating of the transformer is realized by utilizing the heating of the resistors R1 and R2 of the primary winding and the secondary winding, meanwhile, the ratio of the resistors R1 and R2 of the transformer winding to the total impedance is about 1 percent or even lower, Z12 mainly comprises inductive components, when the power frequency is reduced to 1 percent of the rated frequency, Z12 is also reduced to about 1 percent, the applied voltage is also greatly reduced under the same heating current, the output capacity of the heating power is also reduced to about 1 percent of the power frequency power, and the electric quantity consumed by the heating capacity of the power can be greatly reduced; the installation and maintenance are convenient; the damage of connecting wires in the power supply system or the influence on core components of the power supply system when electric sparks are generated can be prevented. In the invention, if the connecting wire in the power supply system is aged or generates electric spark after being used for a long time, the thermal expansion pipe expands at a higher temperature, so that the connecting sheet rises to break the connecting wire connected with the U-shaped column, thereby avoiding the damage of a mother board, a switching board, a sampling board and the like in the power supply system.
Referring to fig. 7, the input impedance of the primary side 1 and the primary side 2 terminals at this time is:
when the transformer is heated, the voltage required to be applied to the transformation primary winding is as follows:
U12=In*Z12。
the ratio of the winding resistances R1 and R2 of the large transformer to the total impedance is about 1 percent, even lower, in the above formula, Z12 is mainly composed of inductive components, when the power frequency is reduced to 1 percent of the rated frequency, Z12 is reduced (estimated) to about 1 percent, the applied voltage is greatly reduced under the same heating current, and the output capacity of the heating power supply is reduced to about 1 percent of the power frequency power supply. Therefore, the main advantage of using low frequency power supply for heating is that the same heating current can be achieved, the heating capacity of the required power supply can be greatly reduced, and the power supply is more convenient to implement and use no matter in a factory or in a transformer use site.
The HMI provides a friendly user operation interface for a user and is responsible for information processing and communication. As shown in fig. 10, the touch screen communicates with the card-insertion case through the RS232 communication port to monitor the system status of the power supply in real time. And by reading the state data, the operation parameters such as voltage, current, power, frequency and the like are displayed in real time so as to realize the control of the power supply and the alarm of overcurrent, overheating and the like of the load.
The power supply operation can select two modes of local and remote. In the "local" mode, manual boosting may be performed. If the mode is a remote mode (an optional function), all control right is handed to the upper computer, at this time, the power supply is equivalent to a slave computer, and an instruction sent by the upper computer is received, wherein the detailed information of the HMI interface is as follows:
"ac power supply indication": the lamp is on to indicate that the power supply cabinet has alternating current supply voltage input;
"control electrical start stop": the inside of the power cabinet controls the switch of the UPS;
"run": starting a power supply cabinet and closing a main loop;
"stop": the power supply cabinet stops, and the main loop is disconnected;
"emergency stop": an emergency stop button;
"local remote": selecting a control mode;
"voltage rise": a boost button;
"voltage reduction": a pressure reduction button;
"frequency increase": the frequency is increased;
"frequency reduction": the frequency is reduced.
In summary, the invention discloses a low-frequency heating power supply system of a three-phase integrated power transformer and an operation method thereof, belonging to the technical field of transformers; the invention discloses a three-phase integrated power transformer low-frequency heating power supply system which comprises an incoming line breaker, an incoming line contactor, an outgoing line contactor, a phase-shifting transformer, a low-frequency inverter, a control system and an automatic power-off system, wherein the incoming line breaker is used for input power supply input and cut-off operation, the phase-shifting transformer is used for input power supply boosting and multi-pulse rectification input power supply formation, the incoming line contactor and the outgoing line contactor are used for realizing remote on-off operation of a power supply of a whole machine, the low-frequency inverter part is composed of a plurality of groups of power units and used for three-phase low-frequency output, the power units are universal assemblies, electric quantity consumed by power supply heating capacity can be greatly reduced, meanwhile, the installation and maintenance are convenient, and the influence on core components of the power supply system when connecting lines in the power supply system are damaged or electric sparks are generated is prevented.
Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art can make modifications and equivalents to the embodiments of the present invention without departing from the spirit and scope of the present invention, which is set forth in the claims of the present application.