Hybrid reactive power compensation device

Abstract

The utility model relates to a hybrid reactive power compensation device. The hybrid reactive power compensation device comprises a static var generator, a passive capacitor module and a controller, the static var generator and the passive capacitor module are electrically connected with a power grid; the static var generator comprises an electrolytic capacitor, an IGBT module, a filtering module and a controller. The electrolytic capacitor is electrically connected with the IGBT module, the IGBT module is electrically connected with a power grid through the filtering module, and a first control end of the controller is electrically connected with the IGBT module so as to control the static var generator to generate reactive current to the power grid; the second control end of the controller is electrically connected with the passive capacitor module so as to control the passive capacitor module to send reactive current to a power grid; the static var generator and the passive capacitor module are combined for compensation, the passive capacitor is used for compensating reactive power with relatively stable load, the static var generator is used for rapidly compensating reactive power with relatively rapid change, the advantages of the static var generator and the passive capacitor module are fully exerted, and the device has very high cost performance.

Description

Technical Field

[0001] This application relates to the technical field of distribution systems, and in particular, to a hybrid reactive power compensation device. Background Art

[0002] With the continuous progress of power technology and the continuous growth of the economy, the number of distribution systems has also increased rapidly. As an important part of the distribution system, the reactive power compensation device plays an important role in reducing the reactive power in power transmission and distribution and improving the power factor of the distribution network system. Traditional passive capacitor reactive power compensation devices are divided into discrete device reactive power compensation (contactor switching, thyristor switching, composite switch switching) and intelligent capacitor reactive power compensation. Although they are inexpensive, they have the defect of a small compensation range and are difficult to compensate for the rapidly changing and fluctuating reactive power on the power grid. Now, a hybrid reactive power compensation device that combines a static var generator and a passive capacitor is proposed to make up for the defect that a single passive capacitor reactive power compensation device is difficult to compensate for the rapidly changing and fluctuating reactive power on the power grid. Summary of the Invention

[0003] In view of this, this application proposes a hybrid reactive power compensation device.

[0004] According to one aspect of this application, a hybrid reactive power compensation device is provided, characterized in that it includes: a static var generator and a passive capacitor module;

[0005] Both the static var generator and the passive capacitor module are electrically connected to the power grid;

[0006] The static var generator includes: an electrolytic capacitor, an IGBT module, a filtering module, and a controller; the electrolytic capacitor is electrically connected to the IGBT module, the IGBT module is electrically connected to the power grid through the filtering module, the first control end of the controller is electrically connected to the IGBT module to control the static var generator to send reactive current to the power grid; the second control end of the controller is electrically connected to the passive capacitor module to control the passive capacitor module to send reactive current to the power grid;

[0007] The passive capacitor module includes: a shunt capacitor and a common capacitor; both the shunt capacitor and the common capacitor are electrically connected to the power grid and are suitable for realizing three-phase shunt compensation and three-phase common compensation respectively; the second control end of the controller is electrically connected to the switching switch of the shunt capacitor and the switching switch of the common capacitor.

[0008] In a possible implementation, the filtering module includes: a first inductor, a second inductor, and a filtering capacitor;

[0009] The first inductor and the second inductor are connected in series in the circuit between the IGBT module and the power grid; the filtering capacitor is electrically connected between the first inductor and the second inductor.

[0010] In a possible implementation, the first control terminal of the controller is electrically connected to the IGBT module through a PWM drive circuit.

[0011] In a possible implementation, the controller is electrically connected to the passive capacitor module through an RS485 communication interface.

[0012] In a possible implementation, the common compensation capacitor is composed of three capacitors connected in a triangle; the split compensation capacitor is composed of three capacitors connected in a star.

[0013] In a possible implementation, both the common compensation capacitor and the split compensation capacitor adopt intelligent capacitors.

[0014] Advantageous effects: This application combines the static var generator and the passive capacitor module compensation. The passive capacitor is used to compensate the relatively stable reactive power of the load, and the static var generator is used to quickly compensate the relatively fast-changing reactive power, giving full play to the advantages of both, making the device have a high cost performance. At the same time, there is no need to additionally add a controller for the passive capacitor module. The controller of the static var generator can control the operation of the static var generator and the switching of the passive capacitor module at the same time, realizing reactive power compensation with a large range, high precision and good real-time performance as a whole, and overcoming the deficiencies of a single compensation device such as a small compensation range, low compensation accuracy and poor real-time performance.

[0015] According to the following detailed description of the exemplary embodiments with reference to the accompanying drawings, other features and aspects of the present application will become clear. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The drawings included in the specification and constituting a part of the specification show the exemplary embodiments, features and aspects of the present application together with the specification, and are used to explain the principles of the present application.

[0017] Figure 1 The main structure diagram of the hybrid reactive power compensation device showing the first embodiment of the present application;

[0018] Figure 2 The main structure diagram of the hybrid reactive power compensation device showing the second embodiment of the present application;

[0019] Figure 3 The schematic diagram of the controller of the present application;

[0020] Figure 4 The connection circuit diagram of the controller and the passive capacitor module showing the second embodiment of the present application;

[0021] Figure 5 The circuit diagram of the PWM control circuit showing the present application;

[0022] Figure 6The structural schematic diagram of the drive module showing the first embodiment of the present application is presented. Detailed implementation manners

[0023] Various exemplary embodiments, features, and aspects of the present application will be described in detail below with reference to the accompanying drawings. Identical reference numerals in the drawings denote elements having the same or similar functions. Although various aspects of the embodiments are shown in the drawings, the drawings are not necessarily drawn to scale unless otherwise specified.

[0024] Among them, it should be understood that terms such as "center", "longitudinal", "transverse", "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. They are only for the convenience of describing the present utility model or simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus cannot be construed as a limitation on the present utility model.

[0025] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present utility model, "a plurality" means two or more unless otherwise specifically defined.

[0026] The special term "exemplary" here means "serving as an example, embodiment, or illustration". Any embodiment described as "exemplary" here does not have to be construed as superior to or better than other embodiments.

[0027] In addition, for a better illustration of the present application, numerous specific details are given in the following detailed implementation manners. Those skilled in the art should understand that the present application can also be implemented without some specific details. In some instances, methods, means, elements, and circuits well-known to those skilled in the art are not described in detail to highlight the gist of the present application.

[0028] Figure 1 The main body structure diagram of the hybrid reactive power compensation device showing the first embodiment of the present application is presented; Figure 2 The main body structure diagram of the hybrid reactive power compensation device showing the second embodiment of the present application is presented. As Figure 1As shown in the figure, a hybrid reactive power compensation device includes a static var generator 100 and a passive capacitor module 300. The static var generator 100 and the passive capacitor module 300 are both electrically connected to the power grid. The static var generator 100 includes an electrolytic capacitor C1, an electrolytic capacitor C2, an IGBT module 110, and a filtering module 200. The electrolytic capacitors are electrically connected to the IGBT module 110, and the IGBT module 110 is electrically connected to the power grid through the filtering module 200. The first control terminal of the controller 500 is electrically connected to the static var generator 100 to control the static var generator 100 to send inductive or capacitive reactive current to the power grid. The second control terminal of the controller 500 is electrically connected to the passive capacitor module 300 to control the passive capacitor module 300 to send reactive current to the power grid. The passive capacitor module 300 includes a shunt compensation capacitor 320 and a common compensation capacitor 310. The shunt compensation capacitor 320 and the common compensation capacitor 310 are both electrically connected to the power grid and are suitable for realizing three-phase shunt compensation and three-phase common compensation respectively. The second control terminal of the controller is electrically connected to the switching switch of the shunt compensation capacitor and the switching switch of the common compensation capacitor.

[0029] Here, it should be noted that all devices in the power grid system will generate reactive power more or less. Therefore, a reactive power compensation device is needed to improve the power factor and avoid fines. The static var generator 100 is a shunt-type reactive power compensation FACTS device that can generate or absorb reactive power and can achieve the purpose of quickly and smoothly absorbing inductive and capacitive reactive power. Therefore, the static var generator 100 can be used to compensate for quickly changing and fluctuating reactive power. The passive capacitor module 300 has a simple structure and low cost, can compensate for most of the stable reactive power, reduce the investment in equipment funds, and can also compensate for reactive power well, with high cost performance. In this application, the compensation of the static var generator 100 and the passive capacitor module 300 is combined, and the static var generator 100 and the passive capacitor module 300 are put into use at the same time. The passive capacitor is used to compensate for the relatively stable reactive power of the load, and the static var generator 100 is used to quickly compensate for the relatively fast-changing reactive power, giving full play to the advantages of both, making the device have high cost performance. At the same time, there is no need to additionally increase the controller 500 for the passive capacitor. The controller 500 of the static var generator 100 can control the operation of the static var generator 100 and the switching of the passive capacitor module 300 at the same time, realizing reactive power compensation with a large range, high precision, and good real-time performance, and overcoming the deficiencies of a single compensation device such as a small compensation range, low compensation accuracy, and poor real-time performance.

[0030] The static var generator 100 includes: electrolytic capacitors, an IGBT module 110, a filtering module 200, and a controller; there are two electrolytic capacitors, the electrolytic capacitor C1 is electrically connected to the IGBT module 110, and the electrolytic capacitor C2 is electrically connected to the IGBT module 110. Here, it should be noted that the IGBT module 110 (i.e., insulated gate bipolar transistor) is a switching device with low-voltage control and high-current capacity, having a low on-resistance and a high turn-on speed, capable of withstanding high currents and voltages. The controller 500 can control the operation of the static var generator 100 by controlling the on and off of the IGBT module 110. When the static var generator 100 is put into use, it will generate a current with an amplitude equal to but a phase opposite to that of the reactive component of the load, thereby canceling the reactive power of the load on the power grid, and then reducing the overall reactive power of the system, improving the power factor, and stabilizing the grid voltage.

[0031] Furthermore, the static var generator 100 adopts an I-type NPC three-level rectifier topology. The three-level rectifier topology is a self-commutated bridge circuit. The IGBT module 110 includes 3 groups of three-level half-bridges and forms a three-phase four-wire connection form.

[0032] In a possible implementation, the filtering module 200 includes: a first inductor L1, a second inductor L2, and a filtering capacitor C3; the first inductor L1 and the second inductor L2 are connected in series in the circuit between the IGBT module 110 and the power grid; the filtering capacitor C3 is electrically connected between the first inductor L1 and the second inductor L2. The first inductor L1, the second inductor L2, and the filtering capacitor C3 adopt an LCL connection form to form a second-order low-pass filter circuit, which can effectively filter out high-frequency current components and reduce the impact on the power grid. Furthermore, each of the three-phase lines connecting the IGBT module 110 to the power grid is provided with a filtering module 200 for high-frequency filtering.

[0033] In a possible implementation, the controller 500 adopts a dual-core DSP control chip. Further, the model of the DSP control chip is TMS320F28377D.

[0034] In a possible implementation, the first control end of the controller 500 is electrically connected to the IGBT module 110 through a PWM drive circuit. As Figure 5As shown, the PWM drive circuit is provided with an optocoupler U1_1; the second pin of the optocoupler U1_1 is electrically connected to the PWM control pin of the controller 500 through a resistor R3_1 and a diode VD1_1, the third pin of the optocoupler U1_1 is electrically connected to the PWM control pin of the controller 500 through a resistor R4_1 and a diode VD1_1, and the sixth and seventh pins of the optocoupler U1_1 are electrically connected to the drive gate of the IGBT module 110 through a series-connected triode Q1_1 and triode Q2_1. A parallel-connected resistor R1_1, resistor R2_1, and bidirectional diode D4_1 are also provided on the circuit where the optocoupler U1_1 is electrically connected to the drive gate of the IGBT module 110.

[0035] As Figure 3 shown, the first input end of the controller 500 is electrically connected to the power grid to collect the voltage at the power grid connection point; the second input end of the controller 500 is electrically connected to the load to collect the load current; the third input end of the controller 500 is electrically connected to the static var generator 100 to collect the device current; the fourth input end of the controller 500 is electrically connected to the electrolytic capacitors C1 and C2 to collect the DC voltage across the electrolytic capacitors C1 and C2. The controller 500 collects the grid voltage, load current, device current, and DC voltage, and generates a PWM wave with a specific time sequence. By driving the IGBT module 110 to conduct and turn off through the PWM drive circuit, it can stabilize the DC bus voltage at a constant value and emit a reactive current that is advanced or lagged and has a variable amplitude. When the static var generator 100 is working, the controller 500 detects the reactive component of the load current, and at the same time controls the DC voltage and the device current, so that the device current is equal in amplitude and opposite in direction to this reactive component, thereby canceling the reactive current.

[0036] In a possible implementation, the second control end (RS485 communication interface) of the controller 500 is electrically connected to the passive capacitor module 300 through the RS485 serial communication standard.

[0037] In a possible implementation (Embodiment 1), the common compensation capacitor 310 is composed of three capacitors connected in a triangle; as Figure 1 shown, the capacitors C4, C5, and C6 of the common compensation capacitor 310 are connected in a triangular connection mode, and switching switches are provided in the connection circuit between the capacitors C4, C5, and C6 and the power grid. The second control end (i.e., the RS485 communication interface) of the controller 500 is electrically connected to the input end of the drive module, and the output end of the drive module is electrically connected to the switching switch. The controller 500 controls the input and cut-off of the common compensation capacitor 310 by controlling the on-off of the switching switch. The shunt compensation capacitor 320 is composed of three capacitors connected in a star shape, as Figure 1As shown in the figure, one pole of the shunt compensation capacitors C7, C8, and C9 of the shunt compensation capacitor 320 is electrically connected to the A-phase, B-phase, and C-phase of the power grid respectively, and the other poles of the shunt compensation capacitors C7, C8, and C9 of the shunt compensation capacitor 320 are all electrically connected to the neutral line (N line) of the power grid. A switching switch is provided on the circuit where one pole of the capacitors C7, C8, and C9 is electrically connected to the ABC three-phase lines of the power grid. The controller 500 controls the input and cut-off of the shunt compensation capacitor 320 by controlling the on and off of the switching switch.

[0038] Furthermore, as Figure 6 shown in the figure, the drive module is provided with a drive chip and a relay. The model of the drive chip is STM32F103RBT6; the 485 communication port of the drive chip is electrically connected to the RS485 communication interface of the controller 500. The output end of the drive chip is electrically connected to the input end of the relay, and the output end of the relay is electrically connected to the switching switches of the shunt compensation capacitor 320 and the common compensation capacitor 310. The drive module receives the communication instructions of the controller 500 and controls the input and cut-off of the common compensation capacitor 310 or the shunt compensation capacitor 320 by controlling the on and off of the switching switch through the relay.

[0039] In another possible implementation (Embodiment 2), as Figure 2 shown in the figure, both the common compensation capacitor 310 and the shunt compensation capacitor 320 adopt intelligent capacitors. The intelligent capacitor receives the communication instructions of the controller 500 to operate the input and cut-off of the capacitor. An intelligent controller is also provided inside the intelligent capacitor, and this intelligent controller also has a 485 communication port. The second control end (i.e., the RS485 communication interface) of the controller 500 is electrically connected to the 485 communication port of the intelligent capacitor, and the intelligent controller receives the communication instructions of the controller 500 to switch the capacitor.

[0040] In one possible implementation, as Figure 4 shown in the figure, the RS485 communication interface of the controller 500 is electrically connected to the 485 communication port of the intelligent capacitor through the transceiver U10. Further, the model of the transceiver U10 is ISO3082; the first pin (VCC1 terminal) of the transceiver U10 is connected to the power supply voltage through the capacitor C48; the second pin, the 15th pin, the 10th pin, and the 9th pin (GND terminal) of the transceiver U10 are grounded; the third pin (R terminal), the fourth pin (RE terminal), the fifth pin (DE terminal), and the sixth pin (D terminal) of the transceiver U10 are all electrically connected to the dual-core DSP control chip. The 16th pin (VCC2 terminal) of the transceiver U10 is connected to the +5v operating voltage through the capacitor C49; the 13th pin (B terminal) and the 12th pin (A terminal) of the transceiver U10 are both electrically connected to the 485 communication port of the intelligent controller.

[0041] It further includes: diode Z1, diode Z2, and diode Z3; Diode Z1 is electrically connected to the circuit between the 13th pin (B terminal) of transceiver U10 and the 485 communication port of the intelligent controller; Diode Z3 is electrically connected to the circuit between the 12th pin (A terminal) of transceiver U10 and the 485 communication port of the intelligent controller; Both ends of diode Z2 are respectively electrically connected to the circuit between the 13th pin (B terminal) of transceiver U10 and the 485 communication port of the intelligent controller, and the circuit between the 12th pin (A terminal) of transceiver U10 and the 485 communication port of the intelligent controller.

[0042] It further includes: fuse PT1 and fuse PT2; Fuse PT1 and fuse PT2 are respectively electrically connected to the circuit between the 13th pin (B terminal) of transceiver U10 and the 485 communication port of the intelligent controller, and the circuit between the 12th pin (A terminal) of transceiver U10 and the 485 communication port of the intelligent controller.

[0043] In a possible implementation, multiple common compensation capacitors 310 and multiple split compensation capacitors 320 are both connected to the power grid, and multiple common compensation capacitors 310 and multiple split compensation capacitors 320 both adopt intelligent capacitors; At this time, the intelligent controllers between multiple common compensation capacitors 310 and multiple split compensation capacitors 320 are connected in series in sequence, and the controller 500 only needs to be connected to the intelligent controller of one of the intelligent capacitors to achieve switching control of all intelligent capacitors.

[0044] The embodiments of the present application have been described above. The above description is exemplary and not exhaustive, and is not limited to the disclosed embodiments. Many modifications and variations are obvious to those of ordinary skill in the art in the technical field without departing from the scope and spirit of the described embodiments. The selection of the terms used herein is intended to best explain the principles of the embodiments, practical applications, or improvements to the technologies in the market, or to enable other ordinary technical personnel in the technical field to understand the embodiments disclosed herein.

Claims

1. A hybrid reactive power compensation device, characterized in that, Including: A static var generator and a passive capacitor module; Both the static var generator and the passive capacitor module are electrically connected to the power grid; The static var generator includes: an electrolytic capacitor, an IGBT module, a filtering module and a controller; the electrolytic capacitor is electrically connected to the IGBT module, the IGBT module is electrically connected to the power grid through the filtering module, and a first control end of the controller is electrically connected to the IGBT module to control the static var generator to generate reactive current to the power grid; a second control end of the controller is electrically connected to the passive capacitor module to control the passive capacitor module to generate reactive current to the power grid; The passive capacitor module includes: a shunt compensation capacitor and a common compensation capacitor; both the shunt compensation capacitor and the common compensation capacitor are electrically connected to the power grid and are suitable for realizing three-phase shunt compensation and three-phase common compensation respectively; the second control end of the controller is electrically connected to a switching switch of the shunt compensation capacitor and a switching switch of the common compensation capacitor.

2. The hybrid reactive power compensation device according to claim 1, wherein The filtering module includes: a first inductor, a second inductor and a filtering capacitor; The first inductor and the second inductor are connected in series on a circuit between the IGBT module and the power grid; the filtering capacitor is electrically connected between the first inductor and the second inductor.

3. The hybrid reactive power compensation device according to claim 1, wherein The first control end of the controller is electrically connected to the IGBT module through a PWM drive circuit.

4. The hybrid reactive power compensation device according to claim 3, wherein, The controller is electrically connected to the passive capacitor module through an RS485 communication interface.

5. The hybrid reactive power compensation device according to claim 4, wherein, The common compensation capacitor is composed of three capacitors connected in a triangle; the shunt compensation capacitor is composed of three capacitors connected in a star.

6. The hybrid reactive power compensation device according to claim 4, wherein Both the common compensation capacitor and the shunt compensation capacitor adopt intelligent capacitors.

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