SVG three-phase imbalance treatment device

Abstract

The invention discloses an SVG three-phase imbalance treatment device, which relates to the field of power control and comprises a power distribution assembly, an integrated controller, a monitoring assembly, an unbalanced load and SVG equipment. The power distribution assembly is electrically connected with one end of the integrated controller, the SVG equipment is electrically connected between the power distribution assembly and the integrated controller through a line, and the SVG equipment is used for automatically compensating unbalanced current and reactive power; the other end of the centralized controller is electrically connected with one end of the monitoring assembly, the other end of the monitoring assembly is electrically connected with the unbalanced load, and the monitoring assembly is used for detecting the system current of the unbalanced load; the centralized controller is used for collecting and integrating data of the power distribution assembly and the monitoring assembly so as to control and adjust the SVG equipment; by using the method, unbalanced state information of the three-phase current can be analyzed, and redistribution is carried out on the three-phase current through SVG equipment, so that the relatively balanced three-phase current and load state can be obtained.

Description

Technical Field

[0001] The invention relates to the field of power control, in particular to an SVG three-phase unbalance control device. Background Art

[0002] Power quality is a key indicator that reflects the level of power grid construction and production operation. The distribution network operation guidelines stipulate that the unbalance of distribution transformers should not be greater than 15%, the allowable deviation of 10kV and below three-phase power supply voltage is ±10% of the nominal system voltage, the allowable deviation of 220V single-phase power supply voltage is +7% to -10% of the nominal system voltage, and the neutral line current should not exceed 25% of the rated current.

[0003] At present, the State Grid has serious problems with seasonal loads in its distribution network. The air-conditioning load is heavy in summer and the electric heating load is heavy in winter. Due to the uncertainty of the load, the three-phase imbalance problem is serious.

[0004] In view of the above problems, the present invention provides an SVG three-phase unbalance control device to solve the above problems. Summary of the invention

[0005] To achieve the above object, the present invention provides the following technical solutions: an SVG three-phase unbalance management device, comprising: a power distribution component, a centralized controller, a monitoring component, an unbalanced load, and an SVG device;

[0006] The power distribution component is electrically connected to one end of the centralized controller, and the SVG device is electrically connected to the line between the power distribution component and the centralized controller, and the SVG device is used to automatically compensate for unbalanced current and reactive power;

[0007] The other end of the centralized control is electrically connected to one end of the monitoring component, and the other end of the monitoring component is electrically connected to the unbalanced load. The monitoring component is used to detect the system current of the unbalanced load; the centralized controller is used to collect and integrate the data of the power distribution component and the monitoring component to control and adjust the SVG device.

[0008] Further, preferably, the state grid transformer wiring, the first voltmeter, the second voltmeter, the third voltmeter, the first ammeter, the second ammeter, the third ammeter;

[0009] The state grid transformer wiring extends a three-wire four-phase circuit, wherein the three-wire four-phase circuit is a live wire A1, a live wire B1, a live wire C1 and a neutral wire N1;

[0010] The live wire A1 is electrically connected in parallel with the first voltmeter and in series with the first ammeter; an output end of the first ammeter is electrically connected to the centralized controller;

[0011] The live wire B1 is electrically connected in parallel with the second voltmeter and in series with the second ammeter; the output end of the second ammeter is electrically connected to the centralized controller;

[0012] The live wire C1 is electrically connected in parallel with the third voltmeter and in series with the third ammeter; the output end of the third ammeter is electrically connected to the centralized controller;

[0013] The neutral line N1 is connected to the centralized controller.

[0014] Further, preferably, the monitoring component comprises: a first current transformer, a second current transformer, and a third current transformer;

[0015] The first current transformer is connected to the live wire A end of the centralized controller and the unbalanced load; the second current transformer is connected to the live wire B end of the centralized controller and the unbalanced load; the third current transformer is connected in series to the live wire C end of the centralized controller and the unbalanced load; and

[0016] The neutral line terminal of the centralized controller is connected to the neutral line terminal of the unbalanced load.

[0017] Further, preferably, the first current transformer, the second current transformer, and the third current transformer are respectively used to detect the system current at the live wire A end, the live wire B end, and the live wire C end of the unbalanced load system, and transmit the system current to the centralized controller.

[0018] Further, preferably, the SVG device extends a three-wire four-phase circuit, which are: a live wire A2, a live wire B2, a live wire C2 and a neutral wire N2;

[0019] The live wire A1 is connected to the live wire A2; the live wire B1 is connected to the live wire B2; the live wire C1 is connected to the live wire C2; ​​and the neutral wire N1 is connected to the neutral wire N2.

[0020] Further, preferably, line switches are respectively provided between the live wire A1 and the live wire A2, between the live wire B1 and the live wire B2, between the live wire C1 and the live wire C2, and between the neutral wire N1 and the neutral wire N2.

[0021] Further, preferably, the SVG device comprises: a second voltage transformer, a first voltage transformer, a first power regulating component, a second power regulating component, and a third power regulating component;

[0022] The second voltage transformer is electrically connected to the first voltage transformer on a first circuit; the first power regulating component, the second power regulating component and the third power regulating component are connected in parallel via the first circuit;

[0023] A second line is extended between the second voltage transformer and the first voltage transformer, and the second line is connected to the neutral line N2; the first power regulating component is connected to the live wire A2; the second power regulating component is connected to the live wire B2; and the third power regulating component is connected to the live wire C2.

[0024] Further, preferably, mutual inductance coils are arranged in series between the live wire A2, the live wire B2, and the live wire C2.

[0025] Further, preferably, the first power regulating component, the second power regulating component and the third power regulating component each include two IGBT power converters, and the two IGBT power converters are connected in series.

[0026] Compared with the prior art, the present invention provides a SVG three-phase unbalance control device having the following features:

[0027] Beneficial effects:

[0028] External current transformers are connected to the live wire A end, live wire B end and live wire C end of the unbalanced load. The current is detected by the current transformer and the information is sent to the centralized controller. The centralized controller obtains the zero-sequence and negative-sequence components by analyzing the unbalanced state information of the three-phase current, and uses the IGBT power converter to redistribute the active load of the three-phase circuit to obtain a relatively balanced three-phase current and load state. At the same time, there is an overload protection function inside the equipment. When the system compensation amount is greater than the device capacity, the device can automatically limit the output to the rated capacity and no overload will occur. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a circuit diagram of an SVG three-phase unbalance management device;

[0030] Figure 2 This is an SVG three-phase unbalance treatment device SVG equipment power diagram.

[0031] In the figure: 1. State Grid transformer wiring; 2. First voltmeter; 3. Second voltmeter; 4. Third voltmeter; 5. First ammeter; 6. Second ammeter; 7. Third ammeter; 8. First current transformer; 9. Second current transformer; 10. Third current transformer; 11. Unbalanced load; 12. Second voltage transformer; 13. First voltage transformer; 14. First power regulating component; 15. Second power regulating component; 16. Third power regulating component; 17. Centralized controller; 18. Line switch; 19. Mutual inductance coil. DETAILED DESCRIPTION

[0032] Reference Figures 1-2 , the present invention provides a technical solution: a SVG three-phase unbalanced treatment device, comprising: a power distribution component, a centralized controller 17, a monitoring component, an unbalanced load 11, and an SVG device;

[0033] The power distribution component is electrically connected to one end of the centralized controller, and the SVG device is electrically connected to the line between the power distribution component and the centralized controller, and the SVG device is used to automatically compensate for unbalanced current and reactive power;

[0034] The other end of the centralized control is electrically connected to one end of the monitoring component, and the other end of the monitoring component is electrically connected to the unbalanced load 11. The monitoring component is used to detect the system current of the unbalanced load 11; the centralized controller 17 is used to collect and integrate the data of the power distribution component and the monitoring component to control and adjust the SVG device.

[0035] It should be noted that the SVG device can be equivalent to an AC voltage source with controllable amplitude and phase and the same frequency as the power grid, and is connected to the power distribution component through an AC reactor.

[0036] For an ideal SVG device (without power loss), the reactive exchange with the unbalanced load 11 system can be adjusted by simply changing the amplitude of its output voltage; when the output voltage is less than the unbalanced load 11 system voltage, the SVG device operates in the "inductive" region (equivalent to a reactor); when the output voltage is greater than the unbalanced load 11 system voltage, the SVG device operates in the "capacitive" region (equivalent to a capacitor).

[0037] As a preferred embodiment, the power distribution assembly includes: a state grid transformer wiring 1, a first voltmeter 2, a second voltmeter 3, a third voltmeter 4, a first ammeter 5, a second ammeter 6, and a third ammeter 7;

[0038] The state grid transformer wiring extends a three-wire four-phase circuit, wherein the three-wire four-phase circuit is a live wire A1, a live wire B1, a live wire C1 and a neutral wire N1;

[0039] The live wire A1 is electrically connected in parallel with the first voltmeter 2 and in series with the first ammeter 5; the output end of the first ammeter 5 is electrically connected to the centralized controller 17;

[0040] The live wire B1 is electrically connected in parallel with the second voltmeter 3 and in series with the second ammeter 6; the output end of the second ammeter 6 is electrically connected to the centralized controller 17;

[0041] The live wire C1 is electrically connected in parallel with the third voltmeter 4 and in series with the third ammeter 7; the output end of the third ammeter 7 is connected to the centralized controller 17;

[0042] The neutral line N1 is connected to the centralized controller 17 .

[0043] As a preferred embodiment, the monitoring component includes: a first current transformer 8, a second current transformer 9, and a third current transformer 10;

[0044] The first current transformer 8 is connected between the centralized controller 17 and the live wire A end of the unbalanced load 11; the second current transformer 9 is connected between the centralized controller 17 and the live wire B end of the unbalanced load 11; the third current transformer 10 is connected in series between the centralized controller 17 and the live wire C end of the unbalanced load 11; and

[0045] The neutral line terminal of the centralized controller 17 is connected to the neutral line terminal of the unbalanced load 11 .

[0046] As a preferred embodiment, the first current transformer 8, the second current transformer 9, and the third current transformer 10 are respectively used to detect the system current of the live wire A end, the live wire B end, and the live wire C end of the unbalanced load 11 system, and transmit the system current to the centralized controller 17.

[0047] It should be explained that after the SVG device is turned on, the external first current transformer 8, the second current transformer 9, and the third current transformer 10 are used to perform real-time detection of the system current at the live wire A end, the live wire B end, and the live wire C end of the unbalanced load 11. After the system current detection is completed, the system current information is transmitted to the centralized controller 17. The centralized controller 17 compares the current data measured by the first ammeter 5, the second ammeter 6, and the third ammeter 7 on the live wire A1, the live wire B1, and the live wire C1, and analyzes the three-phase current unbalanced state information to obtain the zero-sequence and negative-sequence components. Finally, the active load of the three-phase circuit is redistributed through the SVG device to obtain a relatively balanced three-phase current and load state.

[0048] The compensation current changes accurately according to the unbalanced state of the unbalanced load 11 system current to ensure that over-compensation will not occur. In addition, the SVG device has an overload protection function inside. When the compensation amount of the system current is greater than the unbalanced load capacity, the SVG device can automatically limit the output to the rated capacity without overload.

[0049] As a preferred embodiment, the SVG device extends a three-wire four-phase circuit, which are: live wire A2, live wire B2, live wire C2 and neutral wire N2;

[0050] The live wire A1 is connected to the live wire A2; the live wire B1 is connected to the live wire B2; the live wire C1 is connected to the live wire C2; ​​and the neutral wire N1 is connected to the neutral wire N2.

[0051] As a preferred embodiment, line switches 18 are respectively provided between the live wire A1 and the live wire A2, between the live wire B1 and the live wire B2, between the live wire C1 and the live wire C2, and between the neutral wire N1 and the neutral wire N2.

[0052] As a preferred embodiment, the SVG device includes: a second voltage transformer 12, a first voltage transformer 13, a first power regulating component 14, a second power regulating component 15, and a third power regulating component 16;

[0053] The second voltage transformer 12 and the first voltage transformer 13 are electrically connected to a first circuit; the first power regulating component 14, the second power regulating component 15, and the third power regulating component 16 are connected in parallel via the first circuit;

[0054] A second line is extended between the second voltage transformer 12 and the first voltage transformer 13, and the second line is connected to the neutral line N2; the first power regulating component 14 is connected to the live wire A2; the second power regulating component 15 is connected to the live wire B2; and the third power regulating component 16 is connected to the live wire C2.

[0055] As a preferred embodiment, mutual inductance coils are serially arranged between the live wire A2, the live wire B2, and the live wire C2.

[0056] As a preferred embodiment, the first power regulating component 14, the second power regulating component 15, and the third power regulating component 16 each include two IGBT power converters, and the two IGBT power converters are connected in series.

[0057] Embodiment 1

[0058] Compensation process of dynamic reactive power compensation function:

[0059] The first current transformer 8, the second current transformer 9, and the third current transformer 10 perform real-time detection on the system current at the live wire A end, the live wire B end, and the live wire C end of the unbalanced load 11, and after completing the system current detection, transmit the system current information to the centralized controller 17. At the same time, the system current value is compared with the current values ​​on the live wires A1, B2, and C2, so as to analyze and obtain the reactive power of the system.

[0060] After the reactive power of the system is obtained, a capacitive or inductive fundamental current is generated through the IGBT power converter, and finally the dynamic tracking compensation of the reactive power of the load is realized. When the voltage measured by the first voltmeter 2, the second voltmeter 3, and the third voltmeter 4 on the live wire A1, the live wire B1, and the live wire C1 exceeds the upper limit (Umax) of the allowable voltage, the IGBT power converter generates an inductive current, and the inductive current is offset by the live wire A1, the live wire B1, and the live wire C1 through the live wire A2, the live wire B2, and the live wire C2, so as to achieve the purpose of reducing the voltage; on the contrary, when the voltage measured by the first voltmeter 2, the second voltmeter 3, and the third voltmeter 4 on the live wire A1, the live wire B1, and the live wire C1 is lower than the lower limit (Umin) of the allowable voltage, the IGBT power converter generates a capacitive current, and the capacitive current is compatible with the live wire A1, the live wire B1, and the live wire C1 through the live wire A2, the live wire B2, and the live wire C2, so as to achieve the purpose of raising the voltage. Thus, the flow of reactive power is suppressed at the source, achieving overall energy saving in the distribution network.

[0061] During use, the target value of reactive power compensation can be set through the operation panel of the SVG device to achieve smooth compensation without inrush current impact on the load and the power grid.

[0062] Embodiment 2

[0063] Compensation process of active filtering function:

[0064] The first current transformer 8, the second current transformer 9, and the third current transformer 10 detect the system current of the live wire A end, the live wire B end, and the live wire C end of the unbalanced load 11 in real time, and transmit the system current information to the centralized controller 17 after completing the system current detection. The centralized controller 17 calculates the harmonic content in the loop, and after completing the harmonic content calculation, generates a compensation current that is equal to the harmonic content current in magnitude and opposite in direction through the IGBT power converter. The compensation current is connected to the live wire A1, the live wire B1, and the live wire C1 through the live wire A2, the live wire B2, and the live wire C2, thereby suppressing harmonics and realizing the filtering function.

[0065] What is described above is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. An SVG three-phase unbalance control device, characterized by: include: Power distribution components, centralized controller (17), monitoring components, unbalanced load (11), SVG equipment; The power distribution component is electrically connected to one end of the centralized controller, and the SVG device is electrically connected to the line between the power distribution component and the centralized controller, and the SVG device is used to automatically compensate for unbalanced current and reactive power; The other end of the centralized control is electrically connected to one end of the monitoring component, and the other end of the monitoring component is electrically connected to the unbalanced load (11). The monitoring component is used to detect the system current of the unbalanced load (11); the centralized controller (17) is used to collect and integrate the data of the power distribution component and the monitoring component to control and adjust the SVG device.

2. The SVG three-phase unbalance treatment device according to claim 1 is characterized in that: The power distribution assembly comprises: a state grid transformer wiring (1), a first voltmeter (2), a second voltmeter (3), a third voltmeter (4), a first ammeter (5), a second ammeter (6), and a third ammeter (7); The state grid transformer wiring extends a three-wire four-phase circuit, wherein the three-wire four-phase circuit is a live wire A1, a live wire B1, a live wire C1 and a neutral wire N1; The live wire A1 is electrically connected in parallel with the first voltmeter (2) and in series with the first ammeter (5); the output end of the first ammeter (5) is electrically connected to the centralized controller (17); The live wire B1 is electrically connected in parallel with the second voltmeter (3) and electrically connected in series with the second ammeter (6); the output end of the second ammeter (6) is electrically connected to the centralized controller (17); The live wire C1 is electrically connected in parallel with the third voltmeter (4) and in series with the third ammeter (7); the output end of the third ammeter (7) is electrically connected to the centralized controller (17); The neutral line N1 is connected to the centralized controller (17).

3. The SVG three-phase unbalance treatment device according to claim 2 is characterized in that: The monitoring component comprises: a first current transformer (8), a second current transformer (9), and a third current transformer (10); The first current transformer (8) is connected between the centralized controller (17) and the live wire A end of the unbalanced load (11); the second current transformer (9) is connected between the centralized controller (17) and the live wire B end of the unbalanced load (11); the third current transformer (10) is connected in series between the centralized controller (17) and the live wire C end of the unbalanced load (11); and The neutral line terminal of the centralized controller (17) is connected to the neutral line terminal of the unbalanced load (11).

4. The SVG three-phase unbalance treatment device according to claim 3 is characterized in that: The first current transformer (8), the second current transformer (9), and the third current transformer (10) are respectively used to detect the system current of the live wire A end, the live wire B end, and the live wire C end of the unbalanced load (11) system, and transmit the system current to the centralized controller (17).

5. The SVG three-phase unbalance treatment device according to claim 4 is characterized in that: The SVG device extends a three-wire four-phase circuit, which are: live wire A2, live wire B2, live wire C2 and neutral wire N2; The live wire A1 is connected to the live wire A2; the live wire B1 is connected to the live wire B2; the live wire C1 is connected to the live wire C2; ​​and the neutral wire N1 is connected to the neutral wire N2.

6. The SVG three-phase unbalance treatment device according to claim 5, characterized in that: Line switches (18) are respectively provided between the live wire A1 and the live wire A2, the live wire B1 and the live wire B2, the live wire C1 and the live wire C2, and the neutral wire N1 and the neutral wire N2.

7. The SVG three-phase unbalance treatment device according to claim 6 is characterized in that: The SVG device comprises: a second voltage transformer (12), a first voltage transformer (13), a first power regulating component (14), a second power regulating component (15), and a third power regulating component (16); The second voltage transformer (12) and the first voltage transformer (13) are electrically connected to a first circuit; the first power regulating component (14), the second power regulating component (15), and the third power regulating component (16) are connected in parallel via the first circuit; A second line is extended between the second voltage transformer (12) and the first voltage transformer (13), and the second line is connected to the neutral line N2; the first power regulating component (14) is connected to the live line A2; the second power regulating component (15) is connected to the live line B2; and the third power regulating component (16) is connected to the live line C2.

8. The SVG three-phase unbalance treatment device according to claim 7, characterized in that: Mutual inductance coils are connected in series between the live wire A2, the live wire B2, and the live wire C2.

9. The SVG three-phase unbalance treatment device according to claim 7, characterized in that: The first power regulating component (14), the second power regulating component (15), and the third power regulating component (16) each include two IGBT power converters, and the two IGBT power converters are connected in series.

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