Voltage regulation device for long-distance power supply system, regulation and control method and intelligent regulation and control device

Abstract

The invention provides a voltage regulation device for a long-distance power supply system, a regulation and control method and an intelligent regulation and control device. The voltage regulating device comprises a step-down autotransformer, a compensation voltage regulator and a compensation transformer, wherein the step-down autotransformer comprises a single three-phase autotransformer with a fixed transformation ratio; the compensation voltage regulator comprises three single-phase self-coupling voltage regulators, the input ends of the three single-phase self-coupling voltage regulators are connected with the output end of the voltage reduction self-coupling transformer in a Y-shaped wiring mode, and the output end of each single-phase self-coupling voltage regulator is provided with a front movable electric brush and a rear movable electric brush; the compensation transformer comprises three single-phase isolation transformers with fixed transformation ratios, and the input end of each single-phase isolation transformer is electrically connected with the front movable electric brush and the rear movable electric brush of the corresponding single-phase self-coupling voltage regulator. According to the invention, the voltage regulating device is arranged in the shunt branch, and the structure of the autotransformer, the compensation voltage regulator and the compensation transformer is adopted to realize voltage compensation.

Description

Technical Field

[0001] The present invention relates to the technical field of electric power supply, and in particular to a voltage regulating device, a regulating method and an intelligent regulating device for a long-distance power supply system. Background Art

[0002] In industrial production, the distance between equipment and power supply system is increasing, and some power supply distances have reached 2,000 to 3,000 meters. As the power supply distance increases, the voltage loss on the cable line continues to increase, resulting in low terminal voltage on the end load side, affecting the normal operation of electrical equipment. According to the GB / T 12325-2008 "Power Quality Supply Voltage Deviation" standard, when the three-phase power supply voltage level is ≤10kV, the power supply voltage is allowed to deviate by ±7% of the rated voltage. In actual long-distance power supply, due to the influence of line impedance and load changes, the terminal voltage often exceeds this range, resulting in difficulty in starting the equipment or unstable operation.

[0003] The existing technology mainly uses transformer voltage regulation to adjust the voltage. Off-excitation voltage regulation requires the transformer to be shut down to switch the tap, which is not suitable for continuous power supply. Although on-load voltage regulation can switch taps under load, since the equipment directly bears the entire load current and voltage, the voltage and current carrying capacity of each turn of the winding are too large, posing a safety hazard. Mobile substations regulate voltage by increasing the voltage level of the secondary coil, but the voltage regulation fluctuates greatly and the entire set of equipment needs to be replaced, which is costly. These existing technical solutions are difficult to achieve stable control of the terminal voltage of long-distance power supply systems. Summary of the invention

[0004] The object of the present invention is to provide a voltage regulating device, a regulating method and an intelligent regulating control device for a long-distance power supply system, which are used to solve the technical problem that the terminal voltage of the long-distance power supply system is difficult to stabilize within the standard allowable range.

[0005] In order to achieve the above-mentioned object, a first aspect of the present invention provides a voltage regulating device for a long-distance power supply system, wherein the voltage regulating device is used to perform compensatory voltage regulation on a main power supply line through a shunt branch, wherein the voltage regulating device comprises a step-down autotransformer, a compensating voltage regulator and a compensating transformer, wherein: The step-down autotransformer comprises a single three-phase autotransformer with a fixed transformation ratio; The compensating voltage regulator comprises three single-phase auto-coupling voltage regulators, the input ends of the three single-phase auto-coupling voltage regulators are connected to the output end of the step-down auto-coupling transformer in a Y-type wiring manner, and the output end of each single-phase auto-coupling voltage regulator is respectively provided with a front movable brush and a rear movable brush; and The compensation transformer includes three single-phase isolation transformers with fixed transformation ratios. The input end of each single-phase isolation transformer is electrically connected to the front movable brush and the rear movable brush of the corresponding single-phase autovoltage regulator, and the output end of each single-phase isolation transformer is used to be connected in series with the main power supply line at the end of the shunt branch.

[0006] In the voltage regulating device as described above, optionally, the single-phase autotransformer voltage regulator includes a vertical iron core and a column winding wound on the vertical iron core, the front movable brush and the rear movable brush are located in the front and rear rows of the column winding, and the conversion between boost and buck is achieved by changing the cross-coordination of the positions of the two brushes.

[0007] In the voltage regulating device as described above, optionally, the compensating voltage regulator adopts a single-layer copper winding.

[0008] In order to achieve the aforementioned object, a second aspect of the present invention provides a voltage control method for a long-distance power supply system, wherein the power supply system comprises a main power supply line and a shunt branch connected in parallel with the main power supply line, wherein the shunt branch is provided with a voltage regulating device as described in any one of the aforementioned first aspects, wherein the voltage regulating device is connected in series with the main power supply line at the end of the shunt branch, and the voltage control method comprises the following steps: Collect the voltage, line current and power factor at the output end of the compensation transformer; Calculating the actual voltage at the end of the main power supply line based on the resistance and reactance parameters of the main power supply line; and When the actual voltage is less than the preset voltage lower limit, the front movable brush and the rear movable brush are controlled to move forward to adjust the voltage. When the actual voltage is greater than the preset voltage upper limit, the front movable brush and the rear movable brush are controlled to move reverse to adjust the voltage.

[0009] In the voltage control method as described above, optionally, the preset voltage lower limit is 93%~97% of the rated voltage, and the preset voltage upper limit is 103%~107% of the rated voltage.

[0010] In the voltage control method as described above, optionally, the voltage control method further includes fault diagnosis, and the fault diagnosis includes: Monitoring system operating parameters; When the system operating parameters are abnormal, alarm and protection are performed; and Record fault information.

[0011] In order to achieve the above-mentioned object, the third aspect of the present invention provides an intelligent control device for a long-distance power supply system, wherein the intelligent control device comprises: The voltage regulating device as described in any one of the first aspects above; A PLC control unit electrically connected to the voltage regulating device; A current transformer and a voltage transformer are arranged at the output end of the compensation transformer; A touch screen electrically connected to the PLC control unit, the touch screen being used to display and set voltage regulation parameters.

[0012] In the aforementioned intelligent control device, optionally, the touch screen includes a working mode switching module for realizing switching between automatic voltage regulation and manual voltage regulation.

[0013] In the intelligent control device as described above, optionally, the touch screen displays real-time line voltage and current parameters, power factor and parameter curves of the voltage regulation process.

[0014] In the intelligent control device as described above, optionally, the PLC control unit includes a fault diagnosis module, which includes a parameter monitoring unit, an alarm unit and a data recording unit connected in sequence, the parameter monitoring unit is electrically connected to the current transformer and the voltage transformer, the alarm unit is used to send an alarm signal when abnormal parameters are detected, and the data recording unit is used to record fault information.

[0015] By adopting the above technical solution, the present invention realizes voltage compensation by setting a voltage regulating device in the shunt branch and adopting the structure of "autotransformer + compensating voltage regulator + compensating transformer", in which the compensating voltage regulator only bears part of the load current, effectively reducing the voltage and current stress of the equipment. At the same time, through the cross-coordination of the front and rear active brushes, smooth step-up and step-down regulation is realized, ensuring the stability of the terminal voltage of the power supply system.

[0016] In a further optional technical solution, by adopting the Y-type connection method of three single-phase auto-voltage regulators, the compensating voltage regulator can evenly share the voltage and current. The front and rear movable brushes are respectively set at the output end of the single-phase auto-voltage regulator, and the voltage can be accurately adjusted by adjusting the relative position of the two brushes. The compensating transformer adopts a structure in which three single-phase isolation transformers are connected in series with the main power supply line, which not only realizes voltage compensation but also plays an electrical isolation role, further improving the safety and reliability of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 FIG. 1 is a schematic diagram of the structure of a voltage regulating device for a long-distance power supply system in an embodiment of the present invention. Figure 2 Schematic diagram of a Y-type connection mode of a compensating voltage regulator in an embodiment of the present invention, Figure 3 is a flow chart of a voltage control method for a long-distance power supply system in an embodiment of the present invention. Figure 4 is a schematic diagram of a human-machine interface of an intelligent control device in an embodiment of the present invention, Figure 5 Schematic diagram of a fault recording interface of an intelligent control device in one embodiment of the present invention. DETAILED DESCRIPTION

[0018] Before describing the specific implementation methods of the present invention in detail, it should be noted that for the sake of ease of description, specific terms may be used herein, but they do not limit the scope of protection of the present invention. "Long-distance power supply" refers to a power supply method with a long transmission line. In the present invention, long-distance power supply can be a power supply line of several hundred meters to several thousand meters, but is not limited to this range; "shunt branch" refers to a circuit branch connected in parallel with the main power supply line, which is used to share part of the current of the main line; "step-down autotransformer" refers to a transformer with a primary coil and a secondary coil in common, which is used to reduce the input voltage; "compensating voltage regulator" refers to a device that achieves voltage regulation by changing the winding turns ratio. In the present invention, a column voltage regulator structure is used; "front movable brush" and "Rear movable brushes" refer to movable conductive contacts arranged in the front and rear rows of the compensating voltage regulator column winding, which are used to draw power from different positions of the winding to achieve voltage regulation; "column winding" refers to the wire winding wound on the vertical iron core, which is used to achieve voltage conversion; "Y-type wiring" refers to a wiring method in a three-phase circuit, in which one end of the three-phase winding is connected to a common point (neutral point); "isolation transformer" refers to a transformer with completely insulated primary and secondary coils, which is used to achieve electrical isolation; "series compensation" refers to the method of superimposing the compensation voltage on the main power supply line. In the specific implementation methods below, the above terms will be used many times, but their meanings are not limited to the above explanations. Those skilled in the art can make appropriate understanding and expansion of these terms according to actual needs.

[0019] The embodiments of the present invention are described to help those skilled in the art better understand the present invention, but the protection scope of the present invention is not limited to the described embodiments. Those skilled in the art should understand that, without departing from the principle and essence of the present invention, various changes, modifications, substitutions and variations can be made to these embodiments, which should all be within the protection scope of the present invention.

[0020] Embodiment 1 The following is combined with Figure 1 and attached Figure 2 The long-distance power supply voltage regulating device of the present invention is described in detail.

[0021] like Figure 1As shown, the voltage regulating device for the long-distance power supply system includes a step-down autotransformer, a compensating voltage regulator and a compensating transformer connected in sequence. The step-down autotransformer adopts a single three-phase autotransformer with a fixed transformation ratio, which mainly plays a voltage conversion role, and reduces the pressure of the subsequent compensating voltage regulator by reducing the input voltage. The compensating voltage regulator includes three single-phase autotransformers, and the input ends of the three single-phase autotransformers are connected to the output end of the step-down autotransformer.

[0022] like Figure 1 and Figure 2 As shown, the compensating voltage regulator is the core of the entire voltage regulating device, and its high-voltage side input end is Y-connected, the low-voltage side output end is not connected to each other, and there is no common end on the high and low voltage sides. Among them, the front movable brush and the rear movable brush arranged at the output end of each single-phase autotransformer are respectively located in the front and rear rows of the column winding, and the voltage regulation function is realized by taking the voltage difference between the two brushes as the output voltage of the compensating voltage regulator. The three-stage voltage regulation structure of "step-down autotransformer + compensating voltage regulator + compensating transformer" mentioned above is adopted, so that the compensating voltage regulator only needs to work within the voltage range after step-down, and the voltage borne by the voltage regulator is reduced to about ±30% of the input voltage, which greatly improves the safety of the system. The compensating voltage regulator is arranged in the shunt branch and only bears part of the load current. Compared with the traditional voltage regulation method directly connected in series in the main power supply line, it effectively reduces the current carrying requirement of the voltage regulator and prolongs the service life of the equipment. The three single-phase autovoltage regulators use a Y-type wiring method, which provides good three-phase balance characteristics through a stable neutral point potential, overcoming the three-phase imbalance problem in long-distance power supply. At the same time, the voltage of each phase can be adjusted independently, which improves the stability and reliability of the power supply system and solves the voltage fluctuation problem in long-distance power supply.

[0023] Each of the single-phase auto-voltage regulators includes a vertical iron core and a columnar winding wound on the vertical iron core. The following factors need to be considered comprehensively when designing the number of winding turns: If the number of winding turns is insufficient, the voltage distributed on each coil turn will be too high. When the brush moves up and down on the winding, a short circuit will occur between two adjacent coil turns. Excessive voltage will cause excessive short-circuit current, which will lead to overheating of the winding, reduce insulation strength and life, and may even generate electric sparks; and excessively increasing the number of coil turns to reduce the short-circuit current between turns will cause the columnar core to be too high. Therefore, it is necessary to reasonably design the number of winding turns to balance the above problems.

[0024] The vertical core can be made of B20-B50 series silicon steel sheets, and the stacking thickness can range from tens to hundreds of millimeters. It has good magnetic permeability and small iron loss, and the working magnetic density can be controlled according to actual needs. The column winding adopts a single-layer copper winding, and the copper winding can choose enameled wires of different specifications, and is wound on the insulating cylinder in a single layer. The insulating cylinder can be made of epoxy resin or other insulating materials. The single-layer winding method is conducive to heat dissipation and improves the current carrying capacity of the winding. When designing the winding, it is necessary to pay attention to the selection of the number of turns. If the number of turns of the winding is insufficient, the voltage distributed on each turn of the coil will be too high. When the brush moves up and down on the winding, a short circuit will occur between the adjacent two turns of the coil. The excessive voltage will cause the short-circuit current to be too large, which will cause the winding to overheat, reduce the insulation strength and life, and may even generate electric sparks; and if the number of turns of the coil is increased in order to reduce the short-circuit current between turns, the height of the column core will be too high. Therefore, the enameled wire turns need to maintain an appropriate distance to ensure sufficient insulation and heat dissipation space. The outer diameter and total height of the column winding can be determined according to the capacity requirements, and the surface of the winding needs to be polished to ensure good contact of the brush. To solve the above problems, the present invention uses a ratio isolation transformer as a compensation transformer, which not only realizes voltage change and realizes voltage compensation by connecting the output coil in series to the main circuit, but also plays an isolation protection role, thereby improving the insulation and safety of the system.

[0025] In a specific embodiment, for a 10kV voltage level power supply system, the core lamination thickness can be designed to be 150mm, and B35 series silicon steel sheets can be selected; the column winding is wound with a single layer of 3mm² enameled wire, the outer diameter of the winding is selected to be 220mm, and the total height is 700mm. The above parameters are only preferred embodiments and can be adjusted according to actual application requirements.

[0026] A front movable brush and a rear movable brush are respectively arranged at the output end of each single-phase auto-coupling voltage regulator. The front movable brush and the rear movable brush can be made of a variety of conductive materials, such as metal-graphite composite materials, graphite alloy materials, metal copper-graphite materials, etc., all of which have good conductivity, wear resistance and self-lubrication. The front movable brush and the rear movable brush are located in the front and rear rows of the column winding, and the conversion between boost and buck can be achieved by changing the cross-matching of the positions of the two brushes. Specifically, when boosting is required, the front movable brush and the rear movable brush move toward each other along the column winding, that is, the two brushes gradually approach each other; when bucking is required, the front movable brush and the rear movable brush move in opposite directions along the column winding, that is, the two brushes gradually move away from each other; when the voltage is in a suitable range, the movable brush stops moving. In a specific embodiment, a copper-graphite composite material can be used for the brush material selection, wherein the graphite content can be 60-80%. This material has good electrical conductivity, and the self-lubricating property of graphite can reduce the wear of the brush and the winding surface. The movement of the front movable brush and the rear movable brush can be driven by a driving device such as a servo motor or a stepper motor, and can be precisely controlled in conjunction with a position sensor or an encoder.

[0027] The compensation transformer includes three single-phase isolation transformers. The input end of each single-phase isolation transformer is electrically connected to the front active brush and the rear active brush of the corresponding single-phase auto-voltage regulator. The single-phase isolation transformer can use different types of core structures, such as EI type, UI type or rolled core, etc. The core material can use different grades of silicon steel sheets or amorphous alloy materials to meet different magnetic flux density and loss requirements. The primary coil and the secondary coil of the single-phase isolation transformer can be wound in a variety of ways, such as layered winding, overlapping winding, etc., and an insulating shielding layer is set between the coils. The insulating material can be selected from insulating paper, insulating paint or epoxy resin, etc., to improve the insulation strength. In a specific embodiment, an EI type silicon steel sheet core structure can be used, the primary coil and the secondary coil are wound in layers, an insulating shielding layer is added in the middle, and epoxy resin is cast on the outside. This structure not only ensures a good voltage compensation effect, but also has a high insulation strength. The output end of each single-phase isolation transformer is used to be connected in series with the main power supply line, and the voltage after voltage regulation is superimposed on the main power supply line through the compensation transformer.

[0028] By adopting the above technical scheme, the present invention sets a three-stage voltage regulation structure of "step-down autotransformer + compensating voltage regulator + compensating transformer" in the shunt branch, so that the compensating voltage regulator only needs to work within the voltage range after stepping down and only bears part of the load current. Compared with the traditional voltage regulation method directly connected in series in the main power supply line, the voltage and current requirements of the voltage regulator are greatly reduced, and the system safety is improved; the compensating voltage regulator adopts a three-phase Y-type wiring method, and provides good three-phase balance characteristics through a stable neutral point potential. The voltage of each phase can be adjusted independently, overcoming the three-phase imbalance problem in long-distance power supply; the design of the front and rear movable brush structures realizes smooth voltage regulation by changing the brush position, avoiding voltage fluctuations when the traditional voltage regulator switches taps; the compensating transformer adopts an isolated structure, which provides electrical isolation protection while realizing voltage compensation.

[0029] Embodiment 2 The long-distance power supply system provided by the present invention includes a main power supply line and a shunt branch connected in parallel with the main power supply line. The main power supply line undertakes the main power supply task, and its characteristics are long power supply distance, large line impedance, and large voltage drop when large current passes through. In order to solve this problem, the present invention sets a shunt branch and sets a voltage regulating device in the shunt branch. The incoming line end of the shunt branch is connected in parallel with the main power supply line, and the shunt branch is provided with the voltage regulating device as described above, and the output end of the compensation transformer of the voltage regulating device is connected in series with the main power supply line at the end of the shunt branch. This shunt design has the following advantages: first, the shunt branch shares part of the load current, reduces the current burden of the main line, and thus reduces the voltage drop of the main line; second, since the voltage regulating device is arranged in the shunt branch, it will not affect the normal power supply of the main line, thereby improving the system reliability; third, the shunt branch can be flexibly arranged, which is convenient for the installation and maintenance of the voltage regulating device, and at the same time reserves space for system expansion.

[0030] The voltage regulation method of the power supply system adopting this shunt structure includes the following steps: Figure 3 As shown, first, the voltage, line current and power factor of the output end of the compensation transformer are collected. The voltage collection can be achieved by a voltage transformer, the line current collection can be achieved by a current transformer, and the power factor can be obtained by a dedicated measuring device. In a specific embodiment, taking a 10kV power supply system as an example, a voltage transformer with a voltage level of 10kV / 100V and a current transformer with a range of 0-800A can be selected.

[0031] The actual voltage at the end of the main power supply line is calculated according to the resistance and reactance parameters of the main power supply line. The resistance and reactance parameters can be theoretical values ​​calculated according to the model and length of the power supply cable, or they can be actual values ​​obtained through field measurements. In a specific embodiment, for the commonly used YJV22 model power cable, the resistance and reactance values ​​per kilometer can be found in the product manual, and then the total impedance parameters are calculated according to the actual power supply distance. In addition, MYJV22 mining power cable can also be selected, or cables of different models such as VV22, YJY, MHYV, etc. can be selected, and the impedance parameters per unit length of each model of cable can be calculated. The actual voltage can be calculated by a variety of methods. For example, it can be calculated based on the principle of equivalent circuits, considering the distributed parameters of the cable; it can also be calculated by using a simplified model, considering only the lumped parameters of the cable; it can also be calculated according to the actual operating conditions, and a mathematical model containing load characteristics can be established for calculation. The specific calculation method can be selected according to the actual application scenario and accuracy requirements.

[0032] When the actual voltage is less than the preset voltage lower limit, the front movable brush and the rear movable brush are controlled to adjust the voltage. The preset voltage range can be determined according to actual application requirements, and the preset voltage lower limit can be set to 93%~97% of the rated voltage, and the preset voltage upper limit can be set to 103%~107% of the rated voltage.

[0033] In a specific embodiment, taking the rated voltage Un of the power supply system as a reference value, when the actual voltage U2 at the end of the main power supply line is less than the preset voltage lower limit (0.95Un), the front movable brush and the rear movable brush are controlled to move toward each other along the column winding, that is, the two brushes gradually approach each other, and positive adjustment is performed; when the actual voltage U2 is greater than the preset voltage upper limit (1.05Un), the front movable brush and the rear movable brush are controlled to move in the opposite directions along the column winding, that is, the two brushes gradually move away from each other, and negative adjustment is performed; when the actual voltage U2 is within the preset range (0.95Un to 1.05Un), the front and rear movable brushes maintain their current positions.

[0034] In a preferred embodiment, the preset voltage lower limit can be set to 95% of the rated voltage, and the preset voltage upper limit can be set to 105% of the rated voltage. Taking a 10kV power supply system as an example, the voltage lower limit is 9.5kV and the voltage upper limit is 10.5kV. When the actual voltage is lower than 9.5kV, the front movable brush and the rear movable brush are controlled to move toward each other along the column winding to increase the voltage; when the actual voltage is higher than 10.5kV, the front movable brush and the rear movable brush are controlled to move in opposite directions along the column winding to reduce the voltage; when the actual voltage is within the range of 9.5kV to 10.5kV, the front and rear movable brushes maintain their current positions. By setting such a preset voltage range, the voltage stability at the end of the power supply system can be guaranteed, while avoiding frequent operation of the voltage regulating device.

[0035] The voltage regulation method of the present invention also includes a fault diagnosis function, which monitors the system operation parameters in real time and makes fault judgments. The system operation parameters may include multiple parameters such as voltage, current, temperature, etc., and the location of the monitoring point and the type of monitoring parameters may be selected according to actual needs. In a specific embodiment, a temperature sensor may be set at the column winding of the compensating voltage regulator to monitor the winding temperature, a pressure sensor may be set at the active brush to monitor the contact pressure, and voltage and current sampling points may be set at each connection terminal. In a specific embodiment, the following monitoring scheme may be set: a temperature warning is issued when the winding temperature exceeds 90°C, and over-temperature protection is performed when it exceeds 105°C; a warning message is issued when the brush pressure is lower than 80% of the set value; and an alarm is issued when the three-phase voltage imbalance exceeds 4%. When abnormal parameters are monitored, the system will issue an alarm signal and start the corresponding protection measures, and record and store the fault information, including the time of the fault, the type of fault, the values ​​of various parameters at the time of the fault, etc. This information can be saved in the system database for later analysis and maintenance. In addition, the system can also perform trend analysis based on historical data to warn of possible faults. The above monitoring schemes and parameters are only preferred embodiments and can be adjusted according to actual application requirements.

[0036] Embodiment 3 like Figure 4 and Figure 5 As shown, the present invention also provides an intelligent control device for a long-distance power supply system. The intelligent control device includes a voltage regulating device, a PLC control unit, a sensor unit and a touch screen. The voltage regulating device adopts the structure of the first embodiment; the PLC control unit is electrically connected to the voltage regulating device, and is used to receive sensor signals and control the action of the voltage regulating device; the sensor unit includes a current transformer and a voltage transformer arranged at the output end of the compensation transformer, and is used to collect voltage and current signals; the touch screen is electrically connected to the PLC control unit, and is used to display and set voltage regulation parameters.

[0037] The touch screen includes a working mode switching module for switching between automatic voltage regulation and manual voltage regulation. In the automatic voltage regulation mode, the system automatically controls the action of the voltage regulation device according to the detected voltage parameters; in the manual voltage regulation mode, the operator can manually adjust the voltage through the touch screen according to the on-site working conditions.

[0038] The touch screen also displays real-time line voltage and current parameters, power factor, and parameter curves of the voltage regulation process. Figure 4As shown, the parameter display interface includes: the real-time parameter area displays the current voltage, current and power factor values; the alarm information area displays system alarm and fault information; the historical data area can display the voltage regulation parameter curve within a period of time for viewing; the alarm information area displays system alarm and fault information. In a specific embodiment, the touch screen can adopt an industrial-grade touch screen of 10 inches or more, with a good protection level, suitable for use in an industrial environment.

[0039] The PLC control unit includes a fault diagnosis module, which includes a parameter monitoring unit, an alarm unit and a data recording unit. The parameter monitoring unit collects and analyzes system operating parameters in real time; the alarm unit sends an alarm signal when an abnormality is detected; and the data recording unit records system operating parameters and fault information. Figure 5 As shown, the system can display the time, name, parameters and other information of the fault record, which is convenient for operation and maintenance personnel to find and handle faults in time.

[0040] This embodiment realizes intelligent control and visual display of the voltage regulation process through the cooperation of the PLC control unit and the touch screen; the dual-mode switching function meets the voltage regulation requirements under different working conditions; and the complete fault diagnosis function improves the reliability and maintainability of the system.

[0041] Obviously, the above embodiments are merely examples for clearly explaining the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, within the spirit and principles of the present invention, many modifications can be made to these embodiments according to actual needs, and these modifications fall within the scope of protection of the claims of the present invention.

[0042] The long-distance power supply voltage regulating device and its control system provided by the present invention, firstly, by adopting a three-stage voltage regulating structure of "step-down autotransformer + compensating voltage regulator + compensating transformer", the compensating voltage regulator only works within the voltage range after stepping down, which greatly reduces the voltage bearing requirement of the equipment; at the same time, the voltage regulating device is arranged in the shunt branch, instead of being traditionally connected in series in the main power supply line, which significantly reduces the current carrying requirement of the voltage regulator and effectively prolongs the service life of the equipment.

[0043] In terms of electrical performance, the compensating voltage regulator adopts a Y-type wiring method, which provides good three-phase balance characteristics through a stable neutral point potential, and the voltage of each phase can be adjusted independently, overcoming the three-phase imbalance problem in long-distance power supply; the front and rear movable brush design realizes smooth voltage regulation and avoids voltage fluctuations during traditional tap switching; the isolated structure of the compensating transformer provides reliable electrical isolation protection, further improving system safety.

[0044] In terms of control system, the present invention realizes automatic / manual dual-mode voltage regulation control, which can flexibly meet the needs of different working conditions; it is equipped with complete fault diagnosis and data recording functions to improve system reliability; it realizes parameter visualization through touch screen to facilitate operation and maintenance; real-time monitoring and dynamic adjustment ensure the stability of the voltage at the end of the power supply. These intelligent control methods improve the operating efficiency and maintainability of the system.

[0045] In summary, the present invention effectively solves the voltage fluctuation problem in long-distance power supply through innovative structural design and intelligent control scheme, improves the stability and reliability of the power supply system, reduces equipment failure rate, prolongs service life, reduces maintenance costs, and improves economic benefits. These advantages make the present invention have practical value and promotion significance in the field of long-distance power supply.

[0046] Obviously, the above embodiments are merely examples for clearly explaining the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, within the spirit and principles of the present invention, many modifications can be made to these embodiments according to actual needs, and these modifications fall within the scope of protection of the claims of the present invention.

Claims

1. A voltage regulating device for a long-distance power supply system, the voltage regulating device is used to compensate and regulate the voltage of the main power supply line through a shunt branch, characterized in that: The voltage regulating device comprises a step-down autotransformer, a compensating voltage regulator and a compensating transformer, wherein: The step-down autotransformer comprises a single three-phase autotransformer with a fixed transformation ratio; The compensating voltage regulator comprises three single-phase auto-coupling voltage regulators, the input ends of the three single-phase auto-coupling voltage regulators are connected to the output end of the step-down auto-coupling transformer in a Y-type wiring manner, and the output end of each single-phase auto-coupling voltage regulator is respectively provided with a front movable brush and a rear movable brush; and The compensation transformer includes three single-phase isolation transformers with fixed transformation ratios. The input end of each single-phase isolation transformer is electrically connected to the front movable brush and the rear movable brush of the corresponding single-phase autovoltage regulator, and the output end of each single-phase isolation transformer is used to be connected in series with the main power supply line at the end of the shunt branch.

2. The voltage regulating device according to claim 1, characterized in that: Each of the single-phase auto-coupling voltage regulators includes a vertical iron core and a column winding wound on the vertical iron core. The front movable brush and the rear movable brush are located in the front and rear rows of the column winding. The conversion between boost and buck is achieved by changing the cross-coordination of the positions of the two brushes.

3. The voltage regulating device according to claim 1, characterized in that: The compensating voltage regulator adopts a single-layer copper winding.

4. A voltage control method for a long-distance power supply system, characterized in that: The power supply system comprises a main power supply line and a shunt branch connected in parallel with the main power supply line, the shunt branch is provided with a voltage regulating device according to any one of claims 1 to 3, the voltage regulating device is connected in series with the main power supply line at the end of the shunt branch, and the voltage regulation method comprises the following steps: Collect the voltage, line current and power factor at the output end of the compensation transformer; Calculating the actual voltage at the end of the main power supply line based on the resistance and reactance parameters of the main power supply line; and When the actual voltage is less than the preset voltage lower limit, the front movable brush and the rear movable brush are controlled to move forward to adjust the voltage. When the actual voltage is greater than the preset voltage upper limit, the front movable brush and the rear movable brush are controlled to move reverse to adjust the voltage.

5. The voltage control method according to claim 4, characterized in that: The preset voltage lower limit is 93% to 97% of the rated voltage, and the preset voltage upper limit is 103% to 107% of the rated voltage.

6. The voltage control method according to claim 4, characterized in that: The voltage control method further includes fault diagnosis, and the fault diagnosis includes: Monitoring system operating parameters; When the system operating parameters are abnormal, alarm and protection are performed; and Record fault information.

7. An intelligent control device for a long-distance power supply system, characterized in that: The intelligent control device comprises: The voltage regulating device according to any one of claims 1 to 3; A PLC control unit electrically connected to the voltage regulating device; A current transformer and a voltage transformer are arranged at the output end of the compensation transformer; A touch screen electrically connected to the PLC control unit, the touch screen being used to display and set voltage regulation parameters.

8. The intelligent control device according to claim 7, characterized in that: The touch screen includes a working mode switching module for realizing switching between automatic voltage regulation and manual voltage regulation.

9. The intelligent control device according to claim 7, characterized in that: The touch screen displays real-time line voltage and current parameters, power factor, and parameter curves of the voltage regulation process.

10. The intelligent control device according to claim 7, characterized in that: The PLC control unit includes a fault diagnosis module, which includes a parameter monitoring unit, an alarm unit and a data recording unit connected in sequence. The parameter monitoring unit is electrically connected to the current transformer and the voltage transformer. The alarm unit is used to send an alarm signal when an abnormal parameter is detected, and the data recording unit is used to record fault information.

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