Device for realizing power capacitor protection of series filter

Abstract

The utility model provides a device for realizing power capacitor protection by a series filter. The device comprises the series filter and a power capacitor loop, the power capacitor loop comprises a capacitor switching control unit, a capacitor switching device and a capacitor. The beneficial effects are that the series filter is connected in series with the front end of the power capacitor loop, the input end of the series filter is connected with the main incoming line of the power system, and the output end of the series filter is connected with the power capacitor loop; the capacitor switching control unit collects the voltage and current of the power capacitor loop, calculates the power factor value of the loop, and controls the capacitor switching device according to the power factor value. A special reactor does not need to be matched for use, a special silicon controlled rectifier (SCR) switching device does not need to be used, the use energy consumption of the capacitor cabinet is reduced, the cost is reduced, and the service life of the capacitor is prolonged.

Description

Technical Field

[0001] This application relates to the field of power system technology, and more specifically, to a device for implementing power capacitor protection using a series filter. Background Technology

[0002] In today's power grid systems, compensation capacitors are frequently used to improve the power factor. However, due to the extensive use of nonlinear loads in power systems, harmonic components have increased significantly. Even extremely small harmonic components can generate enormous harmonic currents within the compensation capacitors, making them highly susceptible to overheating and damage. Consequently, capacitor bulging, burning out, and even exploding are common occurrences in power system capacitor compensation, becoming a key factor in frequent faults in distribution systems. Their stability and reliability face extremely severe challenges, urgently requiring more advanced technologies and management methods for optimization and improvement to ensure the safe and efficient operation of the power system.

[0003] Currently, within the power system, such as Figure 1 As shown, the most common practice is to connect a reactor 01 in series with each capacitor in a capacitor compensation device to construct the device. The purpose is to increase the impedance of the capacitor circuit, reduce harmonic components within the capacitor, and thus protect the capacitor from damage caused by harmonic overcurrent. However, merely reducing the harmonics in the capacitor circuit does not eliminate them completely. This means that the capacitor operates in a harmonic-containing environment for a long time, which undoubtedly greatly reduces the service life of the capacitor and significantly compromises its stability and durability in the power system. More efficient and precise technical means are urgently needed to improve and optimize this situation in order to maintain the stable operation and long-term efficiency of the power system. Utility Model Content

[0004] The purpose of this disclosure is to provide a device for protecting power capacitors using a series filter, which can solve one or more of the problems mentioned above in the prior art.

[0005] According to one aspect of this disclosure, an apparatus for protecting power capacitors using a series filter is provided, comprising a series filter and a power capacitor circuit; the power capacitor circuit includes a capacitor switching control unit, a capacitor switching device, and a capacitor;

[0006] One end of the first side of the series filter is connected to the main incoming line of the power system, and the other end of the first side of the series filter is connected in series with the capacitor switching device. The capacitor switching device is connected to the capacitor. A measuring transformer is connected to the series filter, and a fuse is provided between the series filter and the main incoming line.

[0007] The second side of the series filter is connected to the capacitor switching control unit, which is connected to the capacitor switching device via wired and wireless means.

[0008] The series filter collects and measures the harmonic parameters of the current transformer in order to control the series filter to eliminate harmonic components in the line;

[0009] Series filters can operate in an active or passive manner.

[0010] The capacitor switching control unit collects the power factor value by measuring the current transformer, and controls the capacitor switching device to switch on the capacitor for compensation.

[0011] Its beneficial effects are as follows: by connecting a series filter in series at the front end of the entire power capacitor circuit, with the input end of the series filter connected to the main incoming line of the power system and the output end connected to the power capacitor circuit; the capacitor switching control unit collects the voltage and current of the main circuit, calculates the power factor value of the circuit, and controls the capacitor switching device based on the power factor value. This series filter can eliminate circuit harmonics, and the capacitor switching control unit coordinates and compensates the capacitor power of the entire system. The device for power capacitor protection using a series filter in this application effectively eliminates harmonic components on the main incoming line of the power system, thereby enabling the downstream capacitors to eliminate harmonic components in the power capacitor circuit, eliminating the need for a reactor 01 and a thyristor SCR switching device, reducing the energy consumption of the capacitor cabinet, lowering costs, and increasing capacitor lifespan.

[0012] In some implementations, a series filter eliminates harmonic components transmitted from the main input line to the load end, so that the capacitor operates at power frequency parameters.

[0013] In some implementations, the series filter is an active voltage-mode or active current-mode filter.

[0014] In some implementations, the cascade filter is configured as follows:

[0015] Collect the harmonic components at the measuring transformer on the first side;

[0016] In addition, the output harmonic components at the output of the series filter are collected;

[0017] Harmonic components in the power capacitor circuit are eliminated by controlling the series filter.

[0018] In some implementations, the capacitor switching control unit acquires the input harmonic components at the inductor inlet of the first side of the series filter via a first measuring transformer located between the series filter and the main input line.

[0019] In some implementations, the capacitor switching control unit acquires the output harmonic components at the inductor outlet of the first side of the series filter via a second measuring transformer, which is located between the series filter and the capacitor switching device.

[0020] In some implementations, the capacitor switching control unit acquires the compensated harmonic components generated on the second side of the series filter via a third measuring transformer.

[0021] The third measuring transformer is located between the second side of the series filter and the capacitor switching control unit.

[0022] In some implementations, the capacitor switching control unit includes a liquid crystal display (LCD) for displaying harmonic parameters.

[0023] This patent eliminates the need for reactors by setting up a series filter. The series filter can eliminate harmonic components on the main incoming line of the power system, as well as harmonic components in the power capacitor circuit. This can greatly reduce the energy consumption of the capacitor bank, reduce costs, and increase the lifespan of the capacitors. Attached Figure Description

[0024] To more clearly illustrate the technical solutions of the embodiments of this disclosure, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are some embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a schematic diagram illustrating the structural principle of a traditional power capacitor protection device.

[0026] Figure 2 This is a schematic diagram illustrating the structural principle of a device for protecting power capacitors using a series filter, as provided in an embodiment of this disclosure. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only some embodiments of this utility model, not all embodiments, and are used only to explain the present utility model and are not intended to limit the present utility model. All other embodiments obtained by those skilled in the art based on the embodiments of this utility model without creative effort are within the scope of protection of this utility model.

[0028] In the description of this utility model, it should be noted that the terms "center," "upper," "lower," "left," "right," "front," "rear," "vertical," "horizontal," "inner," "outer," "both ends," "both sides," "bottom," and "top," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the referred element must have a specific orientation or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model. In addition, the terms "first," "second," "upper-level," "lower-level," "main," and "secondary," etc., are used for descriptive purposes only and can be simply used to more clearly distinguish different components, and should not be construed as indicating or implying relative importance.

[0029] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, an integral connection, a mechanical connection, an electrical connection, a direct connection, or an indirect connection through an intermediate medium, or a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0030] Example:

[0031] In this embodiment, please refer to the appendix to the specification. Figure 2 A device for power capacitor protection using a series filter is provided, comprising a series filter 1 and a power capacitor circuit 2; the power capacitor circuit 2 includes a capacitor switching control unit 21, a capacitor switching device 22, and a capacitor 23.

[0032] One end of the first side of the series filter 1 is connected to the main incoming line 3 of the power system, and the other end of the first side of the series filter 1 is connected in series with the capacitor switching device 22. The capacitor switching device 22 is connected to the capacitor 23. A measuring transformer is connected to the series filter 1, and a fuse 5 is provided between the series filter 1 and the main incoming line 3.

[0033] The second side of the series filter 1 is connected to the capacitor switching control unit 21, and the capacitor switching control unit 21 is connected to the capacitor switching device 22 in a wired and wireless manner.

[0034] Series filter 1 collects and measures the harmonic parameters of the current transformer in order to control the series filter 1 to eliminate harmonic components in the line;

[0035] The capacitor switching control unit 21 collects the power factor value by measuring the current transformer, and controls the capacitor switching device to switch on the capacitor for compensation.

[0036] Among them, the series filter 1 can eliminate the harmonic components transmitted from the main input line 3 to the load end 6, so that the capacitor 23 can operate under the power frequency parameters.

[0037] The series filter 1 of this patent can be either active voltage mode or active current mode.

[0038] Among them, the series filter 1 is configured as follows:

[0039] Collect the harmonic components at the measuring transformer on the first side;

[0040] In addition, the output harmonic components at the output of the series filter 1 are collected;

[0041] The series filter 1 is controlled to eliminate harmonic components in the power capacitor circuit 2.

[0042] The capacitor switching control unit 21 of this patent acquires the input harmonic component at the inductor inlet of the first side of the series filter 1 through the first measuring transformer 41, which is located between the series filter 1 and the main input line 3.

[0043] The capacitor switching control unit 21 of this patent acquires the output harmonic component at the inductor outlet of the first side of the series filter 1 through the second measuring transformer 42, which is located between the series filter 1 and the capacitor switching device 22.

[0044] The capacitor switching control unit 21 of this patent acquires the compensated harmonic components generated on the second side of the series filter 1 through the third measuring transformer 43.

[0045] The third measuring transformer 43 is located between the second side of the series filter 1 and the capacitor switching control unit 21.

[0046] Meanwhile, the capacitor switching control unit 21 of this patent includes a liquid crystal display 211, which can be used to display various harmonic parameters.

[0047] The specific working principle of this patent is as follows: The series filter 1 measures the harmonic voltage and current values ​​transmitted from the main circuit, i.e., the main input line 3 to the load terminal 6, through the first measuring transformer 41 and the second measuring transformer 42. Based on the measured harmonic voltage and current values, an active circuit generates a reverse harmonic current. When the harmonic current passes through the circuit, a reverse harmonic voltage is generated, thereby eliminating harmonics in the capacitor circuit. When the capacitor 23 and the capacitor switching device 22 are working, there are no harmonics in the circuit, only the standard fundamental wave. This achieves centralized elimination of harmonics, protects the capacitor 23 and the capacitor switching device 22, and thus reduces energy consumption.

[0048] The beneficial effects of this patent are as follows: By connecting a series filter 1 in series at the front end of the power capacitor circuit 2, with the input end of the series filter 1 connected to the main incoming line 3 of the power system and the output end of the series filter 1 connected to the power capacitor circuit 2, the capacitor switching control unit 21 collects the voltage and current of the power capacitor circuit 2, calculates the power factor of the circuit, and controls the capacitor switching device 22 based on the power factor. The series filter 1 can simultaneously output a portion of the capacitor power, which is then uniformly coordinated and compensated by the capacitor switching control unit 21 for the entire system's capacitor power. The device for power capacitor protection using a series filter in this application effectively eliminates harmonic components on the main incoming line 3 of the power system through the series filter 1, thereby enabling the downstream capacitor 23 to eliminate harmonic components from the power capacitor circuit 2. This eliminates the need for a dedicated reactor for each capacitor and the need for a silicon controlled rectifier (SCR) switching device, reducing energy consumption in the capacitor bank, lowering costs, and extending capacitor lifespan.

[0049] The above are merely optional embodiments of this disclosure. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of this disclosure, and these improvements and modifications should also be considered within the scope of protection of this disclosure.

Claims

1. A device for protecting power capacitors using a series filter, characterized in that, It includes a series filter (1) and a power capacitor circuit (2); the power capacitor circuit (2) includes a capacitor switching control unit (21), a capacitor switching device (22), and a capacitor (23). One end of the first side of the series filter (1) is connected to the main incoming line (3) of the power system, and the other end of the first side of the series filter (1) is connected in series with the capacitor switching device (22). The capacitor switching device (22) is connected to the capacitor (23). A measuring transformer is connected to the series filter (1), and a fuse (5) is provided between the series filter (1) and the main incoming line (3). The second side of the series filter (1) is connected to the capacitor switching control unit (21), and the capacitor switching control unit (21) is connected to the capacitor switching device (22) in a wired and wireless manner. The series filter (1) collects the harmonic parameters of the measuring transformer in order to control the series filter (1) to eliminate harmonic components in the line; The capacitor switching control unit (21) collects the power factor value of the circuit where the fuse (5) is located, so as to control the capacitor switching device to put the capacitor into the compensation.

2. The device for power capacitor protection using a series filter according to claim 1, characterized in that, The series filter (1) eliminates the harmonic components conducted to the capacitor circuit (2) on the line from the main input line (3) to the load end (6), so that the capacitor (23) operates under power frequency parameters.

3. The device for protecting power capacitors using a series filter according to claim 1, characterized in that, The series filter (1) is either active voltage mode or active current mode.

4. The device for protecting power capacitors using a series filter according to claim 1, characterized in that, The series filter (1) is configured as follows: Harmonic components are collected at the measuring transformer (41) on the first side; In addition, the output harmonic components at the output of the series filter (1) are collected; To control the series filter (1) to eliminate harmonic components in the power capacitor circuit (2).

5. The device for protecting power capacitors using a series filter according to claim 4, characterized in that, The capacitor switching control unit (21) collects the input harmonic components at the inductor entrance of the first side of the series filter (1) through the first measuring transformer (41), which is located between the series filter (1) and the main input line (3).

6. The device for protecting power capacitors using a series filter according to claim 5, characterized in that, The capacitor switching control unit (21) collects the output harmonic component at the first inductor outlet of the series filter (1) through the second measuring transformer (42), which is located between the series filter (1) and the capacitor switching device (22).

7. The device for protecting power capacitors using a series filter according to claim 6, characterized in that, The capacitor switching control unit (21) collects the compensation harmonic components generated on the second side of the series filter (1) through the third measuring transformer (43); The third measuring transformer (43) is located between the second side of the series filter (1) and the capacitor switching control unit (21).

8. The device for protecting power capacitors using a series filter according to claim 7, characterized in that, The capacitor switching control unit (21) includes a liquid crystal display (211) for displaying harmonic parameters.

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