Reactive power compensation device with automatic adjusting function

Abstract

A reactive power compensation device with an automatic adjusting function is used for a power grid bus and comprises a high-voltage isolation switch, a voltage transformer, a current transformer, an adjustable inductor, a vacuum contactor, a capacitor device and an intelligent controller. The adjustable inductor comprises a coil, a magnetic core, a driving mechanism, a forward power switch and a reverse power switch, and a low-voltage control power supply is provided for the driving mechanism through the forward / reverse power switch. The driving mechanism comprises a supporting fixing piece, a reduction gear box, a three-phase asynchronous motor, a linkage movable block, a bearing supporting piece and a rotating bearing. The intelligent controller comprises an acquisition unit, a display unit and a control unit. The number of capacitors can be automatically switched, inductance parameters can be automatically adjusted, the optimal anti-harmonic effect can be achieved, and changes of harmonic interference frequency and the actual situation of a field power grid can be fully adapted. The number of turns of the coil and the cross section area and length of the magnetic core can be adjusted according to the capacity of a power grid system to meet the requirements of the power grid system in different occasions.

Description

Technical Field

[0001] The utility model relates to a high-voltage reactive power compensation device, in particular to a reactive power compensation device with an automatic adjustment function and capable of automatically adjusting inductance parameters. Background Art

[0002] In the field of power transmission, high-voltage transformers have impedance. During power transmission, voltage drop will be generated and change with the load on the user side. The fluctuation of system voltage plus the change of load on the user side will cause a large change in voltage. Under the premise of achieving local balance of reactive power, when the voltage change exceeds the fixed value, in order to maintain the stability of the voltage, the transformer needs to adjust the voltage. Due to the rapid development of power electronics technology, energy-saving lamps, computers, variable frequency speed regulation devices, rectifier equipment and UPS (uninterruptible power supply) and other electrical appliances with nonlinear characteristics are becoming more and more widespread, bringing more and more serious harmonic interference to the power grid, thereby affecting the decline in power quality. The large increase in inductive loads has caused the power factor of users to decline, so active filters and reactive power compensation devices are being used more and more widely.

[0003] As the harmonic interference of the power grid becomes more and more serious, it has a great negative impact on the reactive power compensation device. Harmonics can easily cause the reactive power compensation device to resonate with inductive electrical equipment such as transformers and motors on the power grid. When resonance occurs, a large current will flow through the reactive power compensation device, causing damage to the reactive power compensation device.

[0004] For this reason, the current common high-voltage reactive power compensation device adopts the following measures: a reactor with a capacitive reactance (or capacity) of 5% to 14% of the capacitor is connected in series to avoid the common fifth or third harmonic interference, so as to reduce the harm to the power grid.

[0005] However, the reactors configured in common reactive power compensation devices are 5%, 6%, 7% or 12%, 14%, which are fixed and cannot be changed on site. Therefore, the originally installed reactive power compensation device can be used, but now the on-site power grid conditions have changed, the harmonic interference frequency has changed, and the originally installed reactive power compensation device cannot avoid the harmonic interference frequency. Summary of the invention

[0006] The technical problem to be solved by the utility model is to overcome the defects of the high-voltage reactive power compensation device in the prior art that it has poor adaptability and cannot adapt to the on-site power grid conditions, and to provide a reactive power compensation device with automatic adjustment function that can adapt to the power grid and automatically adjust the inductance parameters to obtain the best anti-harmonic effect.

[0007] The utility model solves the above technical problems through the following technical solutions: a reactive power compensation device with automatic adjustment function, used for a power grid bus, comprising: a high-voltage disconnector, a voltage transformer, a current transformer, an adjustable inductor, a vacuum contactor, a capacitor device, and an intelligent controller.

[0008] The adjustable inductor includes a coil, a magnetic core, a driving mechanism, a forward power switch, and a reverse power switch, and a low-voltage control power supply is provided to the driving mechanism through the forward / reverse power switch. The driving mechanism includes a supporting fixture, a reduction gear box, a three-phase asynchronous motor, a linkage movable block, a bearing support, and a rotary bearing.

[0009] The intelligent controller includes a collection unit, a display unit and a control unit.

[0010] The acquisition unit is used to acquire the signal of the power grid bus and send the signal to the display unit and the control unit.

[0011] Preferably, the display unit is used to display the working information of the reactive power compensation device with automatic adjustment function.

[0012] Preferably, the working information includes one or more of the reactive compensation amount currently provided, the power factor of the grid bus, the harmonic information of the grid bus, the inductance parameters of the adjustable inductor, the capacitance parameters of the capacitor device, or the number and number of capacitor units in operation of the capacitor device.

[0013] The display unit displays a variety of real-time information, which is convenient for operators to grasp the on-site situation, and provides convenience for the installation and operation of the reactive power compensation device with automatic adjustment function.

[0014] Preferably, the control unit is used to generate an inductance control amount and a capacitance control amount according to the signal collected by the collection unit, and control the forward power switch and the reverse power switch in the adjustable inductor according to the inductance control amount, so as to drive the three-phase asynchronous motor in the mechanism to drag the magnetic core to move back and forth in the coil, control the effective length of the magnetic core in the coil, thereby changing the inductance value of the coil to adjust the inductance value in series before the capacitor device; when the magnetic core is fully inserted into the coil, the inductance of the coil is maximum, and when the magnetic core is completely removed from the coil, the inductance of the coil is minimum.

[0015] Preferably, the voltage transformer is used to collect the voltage signal of the power grid bus and transmit it to the collection unit in the intelligent controller.

[0016] Preferably, the current transformer is used to collect the current signal of the power grid bus and transmit it to the collection unit in the intelligent controller.

[0017] Preferably, the capacitor device comprises a plurality of capacitor units connected in parallel, each capacitor unit is connected in series with a vacuum contactor and corresponds to a number, and the intelligent controller controls and conducts the capacitor unit corresponding to the selected number according to the capacitor control amount.

[0018] The parallel connection means that the capacitor unit and the vacuum contactor form a loop and are connected in parallel with each other. Each capacitor unit is connected in series with a vacuum contactor, and the intelligent controller controls the conduction of the capacitor unit by controlling the vacuum contactor. By conducting the capacitor unit corresponding to the number selected, the number of capacitor units that need to be turned on is also confirmed, thereby controlling the number and capacity of capacitor units. The capacitor parameters are adjusted by controlling the number of capacitor units connected in parallel to meet the needs of the power grid.

[0019] By collecting data from the power grid bus, such as voltage signals and current signals, the reactive compensation amount provided by the device can be adjusted. Therefore, the inductance parameters and reactive compensation amount that can be provided by a reactive compensation device with automatic adjustment function are no longer fixed, and can effectively adapt to the installation environment on site.

[0020] By collecting signals from the power grid bus, the existing calculation methods and computing chips can be used to analyze the collected signals and determine the power factor and harmonic information, thereby deriving how much compensation a reactive compensation device with automatic adjustment function needs to provide to meet the demand. A reactive compensation device with automatic adjustment function meets the needs of the power grid by adjusting its own inductance parameters and capacitance parameters.

[0021] The positive progressive effect of the utility model is that the utility model can automatically adjust the inductance parameters to obtain the best anti-harmonic effect, and fully adapt to the change of harmonic interference frequency and the actual situation of the on-site power grid. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a schematic structural diagram of a reactive power compensation device with automatic adjustment function according to an embodiment of the utility model;

[0023] Figure 2 This is a schematic diagram of the structure of the adjustable inductor in the embodiment of the utility model;

[0024] Figure 3 This is a side view of the adjustable inductor internal driving structure in the embodiment of the utility model;

[0025] Figure 4 It is a top view of the adjustable inductor inner driving structure in the embodiment of the utility model. DETAILED DESCRIPTION

[0026] The present invention is further described below by way of embodiments, but the present invention is not limited to the scope of the embodiments.

[0027] See also Figure 1 As shown, this embodiment provides a reactive power compensation device with an automatic adjustment function, which is used for connecting to a power grid bus, and comprises: a high-voltage disconnector (1), a voltage transformer (2), a current transformer (3), an adjustable inductor (4), a vacuum contactor (5), a capacitor device (6), and an intelligent controller (10).

[0028] See also Figure 2 , Figure 3 As shown, the adjustable inductor (4) includes a coil (13), a magnetic core (11), a driving mechanism (14), a forward power switch (12), and a reverse power switch (15), and a low-voltage control power supply is provided to the driving mechanism (14) through the forward / reverse power switches (12, 15). The driving mechanism (14) includes a supporting fixture (16), a reduction gear box (17), a three-phase asynchronous motor (18), a linkage movable block (19), a bearing support (20), and a rotary bearing (21).

[0029] The reduction gearbox (17) is mounted on the supporting fixture (16); the three-phase asynchronous motor (18) is connected to the large gear inside the reduction gearbox (17) via a small gear; the rotary bearing (21) is welded to the center of the large gear; the linkage movable block (19) is fixed to the rotary bearing (21) via a threaded nut; the bottom of the linkage movable block (19) is also fixed above the magnetic core (11); when the forward power switch (12) is powered on, the three-phase asynchronous motor (18) rotates forward, dragging the magnetic core (11) to move outside the coil (13), thereby reducing the inductance of the coil (13); when the reverse power switch (15) is powered on, the three-phase asynchronous motor (18) rotates reversely, dragging the magnetic core (11) to move inside the coil (13), thereby increasing the inductance of the coil (13).

[0030] Preferably, the driving mechanism (14) receives command information from the intelligent controller (10) to automatically drive the relative position of the magnetic core (11) in the coil (13), thereby changing the inductance of the coil (13) to adjust the inductance before being connected in series with the capacitor device (6); when the magnetic core (11) is fully inserted into the coil (13), the inductance of the coil (13) is maximum, and when the magnetic core (11) is fully removed from the coil (13), the inductance of the coil (13) is minimum.

[0031] according to Figure 1 As shown, the intelligent controller (10) comprises a collection unit (7), a display unit (8), and a control unit (9).

[0032] The acquisition unit (7) is used to acquire signals from the power grid bus and send the signals to the display unit (8) and the control unit (9).

[0033] Preferably, the display unit (8) is used to display working information of the reactive power compensation device with automatic adjustment function.

[0034] Preferably, the working information includes one or more of the reactive compensation amount currently provided, the power factor of the grid bus, the harmonic information of the grid bus, the inductance parameter of the adjustable inductor, the capacitance parameter of the capacitor device (6), or the number and serial number of the capacitor units in operation of the capacitor device (6).

[0035] The display unit (8) displays a variety of real-time information, making it convenient for operators to understand the on-site situation, thereby facilitating the installation and operation of the reactive power compensation device with automatic adjustment function.

[0036] Preferably, the control unit (9) is used to generate an inductance control amount and a capacitance control amount according to the signal collected by the collection unit (7), and to control the forward / reverse power switch (12, 15) in the adjustable inductor (4) according to the inductance control amount, so that the three-phase asynchronous motor (18) in the driving mechanism (14) drags the magnetic core (11) to move back and forth in the coil (13), controls the effective length of the magnetic core (11) in the coil (13), thereby changing the inductance value of the coil (13) to adjust the inductance value before being connected in series with the capacitor device (6); when the magnetic core (11) is fully inserted into the coil (13), the inductance of the coil (13) is maximum, and when the magnetic core (11) is fully removed from the coil (13), the inductance of the coil (13) is minimum.

[0037] Preferably, the voltage transformer (2) is used to collect voltage signals from a power grid bus and transmit the voltage signals to a collection unit (7) in the intelligent controller (10).

[0038] Preferably, the current transformer (3) is used to collect current signals from a power grid bus and transmit the current signals to a collection unit (7) in the intelligent controller (10).

[0039] like Figure 1 As shown, the capacitor device (6) includes a plurality of capacitor units connected in parallel, each capacitor unit corresponds to a number, and the capacitor units are numbered 01, 02, and 03 respectively. The parallel connection means that when the capacitor unit and the vacuum contactor (5) form a loop, they are connected in parallel. Each capacitor unit is connected in series with a vacuum contactor (5), and the intelligent controller (10) controls the conduction of the capacitor unit by controlling the vacuum contactor (5).

[0040] The intelligent controller (10) can control the number of capacitor units that are turned on and the capacitor units with designated numbers according to the capacitor control amount.

[0041] The working process of a reactive power compensation device with an automatic adjustment function in this embodiment is as follows: a reactive power compensation device with an automatic adjustment function is connected to a power grid bus, and a collection unit (7) of an intelligent controller (10) of the reactive power compensation device with an automatic adjustment function collects current and voltage signals of the power grid bus through a voltage transformer (2) and a current transformer (3), and transmits the current signal and the voltage signal to a display unit (8) and a control unit (9) in the intelligent controller.

[0042] The control unit (9) analyzes the current signal and the voltage signal to determine the power factor and harmonic information. The intelligent controller (10) generates an inductance control amount and a capacitance control amount according to the reactive power compensation amount required by the power grid.

[0043] The intelligent controller (10) controls the three-phase asynchronous motor (18) in the adjustable inductor (4) by using the inductance control amount, and the rotation of the three-phase asynchronous motor (18) is converted into the linear motion of the magnetic core (11) through the gear and the rack, thereby adjusting the effective length of the magnetic core (11) in the coil (13).

[0044] In this embodiment, through calculation of the power factor and harmonic information, the length of the magnetic core (11) in the coil (13) needs to be 15 cm, and the inductance parameter of the adjustable inductor (4) under the length can meet the requirements of the current power grid bus, and the current length of the magnetic core (11) in the coil (13) is 5 cm, so the intelligent controller (10) controls the direction of the magnetic core (11) entering the coil (13) to move 10 cm. The magnetic core (11) moves 2 mm for each rotation of the three-phase asynchronous motor (18), so in order to make the magnetic core (11) move 10 cm in the direction of entering the coil (13), the intelligent controller (10) controls the three-phase asynchronous motor (18) to rotate 50 times.

[0045] The intelligent controller (10) uses the capacitance control amount to control the number of capacitance units that are turned on and the capacitance units with designated numbers.

[0046] In this embodiment, the capacitance parameters provided by the three capacitor units connected in parallel are required to meet the needs of the current power grid, and currently only the capacitor unit numbered 01 is turned on, so the intelligent controller (10) controls the vacuum contactor (5) connected in series with the capacitor units numbered 02 and 03 to turn on.

[0047] A reactive power compensation device with an automatic adjustment function in this embodiment can automatically adjust the inductance parameters to obtain the best anti-harmonic effect, fully adapting to the change of harmonic interference frequency and the actual situation of the on-site power grid. The utility model can also adjust the number of turns of the coil (13) and the cross-sectional area and length of the magnetic core (11) according to the capacity of the power grid system to meet the needs of power grid systems in different occasions.

[0048] Although the specific embodiments of the present invention are described above, those skilled in the art should understand that these are only examples, and the protection scope of the present invention is defined by the appended claims. Those skilled in the art may make various changes or modifications to these embodiments without departing from the principle and essence of the present invention, but these changes and modifications fall within the protection scope of the present invention.

Claims

1. A reactive power compensation device with automatic adjustment function, used for a power grid bus, comprising: High-voltage isolating switch, voltage transformer, current transformer, adjustable inductor, vacuum contactor, capacitor device, intelligent controller; characterized in that: the adjustable inductor includes a coil, a magnetic core, a driving mechanism, a forward power switch, and a reverse power switch, and a low-voltage control power supply is provided to the driving mechanism through the forward / reverse power switch; the driving mechanism includes a supporting fixture, a reduction gearbox, a three-phase asynchronous motor, a linkage movable block, a bearing support, and a rotating bearing. The reduction gearbox is installed on the supporting fixture, the three-phase asynchronous motor is connected to the large gear inside the reduction gearbox through a small gear, the rotating bearing is welded to the center of the large gear, the linkage movable block is fixed to the rotating bearing through a threaded nut, and the bottom of the linkage movable block is fixed on the top of the magnetic core at the same time. When the forward power switch is energized, the three-phase asynchronous motor rotates forward, dragging the magnetic core to move outside the coil to reduce the inductance of the coil. When the reverse power switch is energized, the three-phase asynchronous motor reverses, dragging the magnetic core Move into the coil to increase the inductance of the coil; the intelligent controller includes a collection unit, a display unit, and a control unit; the voltage transformer is used to collect the voltage signal of the power grid bus and transmit it to the collection unit in the intelligent controller; the current transformer is used to collect the current signal of the power grid bus and transmit it to the collection unit in the intelligent controller; the control unit is used to generate an inductance control amount and a capacitance control amount according to the signal collected by the collection unit, and control the length of the adjustable inductor magnetic core in the coil according to the inductance control amount, and control the capacitance parameter of the capacitor device according to the capacitance control amount; the driving mechanism receives the command information of the intelligent controller to automatically drive the relative position of the magnetic core in the coil, thereby changing the inductance value of the coil to adjust the inductance value in series before the capacitor device. When the magnetic core is fully inserted into the coil, the coil inductance is maximum, and when the magnetic core is completely removed from the coil, the coil inductance is minimum.

2. The reactive power compensation device with automatic adjustment function according to claim 1 is characterized in that: The capacitor device includes a plurality of capacitor units connected in parallel, each capacitor unit is connected in series with a vacuum contactor corresponding to a number, and the intelligent controller controls the capacitor unit to screen the number and turn on the vacuum contactor corresponding to the screened number according to the capacitor control amount, and then puts the corresponding capacitor unit into operation.

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