A harmonic filter device for inter-harmonic management

Abstract

The utility model discloses a kind of heavy harmonic filter devices for interharmonic governance, wherein device includes filter controller, vacuum contactor, filter rheostat, electric reactor and capacitor;The signal output end of the filter controller is connected with the control end of vacuum contactor, for sending action instruction to vacuum contactor according to detected interharmonic, high harmonic data;Vacuum contactor, filter rheostat, electric reactor and capacitor are sequentially connected in series and form filter loop, and the cable line of the two ends of the electric reactor is connected to filter rheostat, form adjustable filter structure;The filter loop is connected with 0.4kV three-phase power supply, and the filter controller is used to detect interharmonic and high harmonic data in 0.4kV three-phase power supply.The utility model belongs to low-voltage electrical apparatus field, specifically refers to a kind of heavy harmonic filter devices for interharmonic governance.

Description

Technical Field

[0001] This utility model belongs to the field of low-voltage electrical devices, specifically referring to a reharmonic filter device for interharmonic wave control. Background Technology

[0002] With the improvement of industrial automation, the power environment in factories is becoming increasingly complex. The widespread application of various nonlinear loads (such as variable frequency speed control equipment, electric arc furnaces, rectifiers, etc.) has led to the existence of not only traditional integer harmonics in low-voltage power systems, but also a large number of interharmonics and higher harmonics.

[0003] Interharmonics refer to harmonics whose frequencies are not integer multiples of the fundamental frequency, typically ranging from 0.5 to several hundred times the fundamental frequency. Higher harmonics, on the other hand, refer to harmonics whose frequencies are integer multiples of the fundamental frequency and whose orders are higher (usually above the 20th). The presence of these harmonics can cause various harms to the power system: firstly, interharmonics can cause additional vibration and noise in equipment such as motors and transformers, accelerating equipment aging and even causing malfunctions and shutdowns; secondly, higher harmonics can interfere with the accuracy of power metering devices, causing metering errors, and may also affect the normal operation of communication systems, leading to signal distortion.

[0004] Currently, harmonic mitigation solutions for low-voltage systems mainly rely on active power filters. Active power filters cancel harmonics by detecting harmonic currents in real time and generating reverse compensation currents. However, their design is primarily geared towards integer harmonics (such as the 3rd, 5th, and 7th harmonics), and their ability to mitigate interharmonics and higher harmonics is severely inadequate. Firstly, the detection algorithms of active power filters are mostly based on Fourier transforms, making it difficult to accurately identify interharmonics at non-integer multiples of frequency. Secondly, the switching frequency of their power devices is limited, making it unable to effectively compensate for high-frequency high-order harmonics. Utility Model Content

[0005] The technical problem this invention aims to solve is that active filters cannot effectively manage intermediate and higher harmonics in low-voltage systems.

[0006] To solve the above problems, the technical solution adopted by this utility model is as follows: The reharmonic filtering device for interharmonic mitigation proposed by this utility model includes a filter controller, a vacuum contactor, a filter rheostat, a reactor, and a capacitor;

[0007] The signal output terminal of the filter controller is connected to the control terminal of the vacuum contactor, and is used to send action commands to the vacuum contactor based on the detected interharmonic and higher harmonic data.

[0008] The vacuum contactor, filter rheostat, reactor, and capacitor are connected in series to form a filter circuit, and the two ends of the reactor are connected to the filter rheostat to form an adjustable filter structure.

[0009] The filter circuit is connected to a 0.4kV three-phase power supply, and the filter controller is used to detect interharmonic and higher harmonic data in the 0.4kV three-phase power supply.

[0010] Furthermore, the filter controller includes a harmonic detection module and a control module; the harmonic detection module is used to acquire voltage and current signals in the 0.4kV three-phase power supply in real time, and analyze them to obtain the frequency and amplitude of interharmonics and higher harmonics; the control module is used to send an on or off command to the vacuum contactor according to the analysis results of the harmonic detection module, and output an adjustment signal to the filter rheostat.

[0011] Furthermore, the filter rheostat is an adjustable resistor with a resistance adjustment range of 0-100Ω. By changing the resistance value, the resonant frequency of the filter circuit can be adjusted to match interharmonics and higher harmonics of different frequencies.

[0012] Furthermore, the capacitors, reactors, vacuum contactors, and filter rheostats are all modular structures, which facilitates on-site construction, installation, and subsequent modifications.

[0013] The beneficial effects of this utility model by adopting the above structure are as follows:

[0014] 1. The re-harmonic filter device for interharmonic mitigation proposed in this solution, through its adjustable filter structure design, can specifically mitigate interharmonics and higher harmonics, thus overcoming the limitation of active filters that can only handle integer harmonics.

[0015] 2. The resonant filter device for interharmonic mitigation proposed in this solution is built with hardware circuitry, requiring no complex digital control algorithms. It has strong anti-interference capabilities and can operate stably in harsh industrial environments such as high temperature and dust, reducing the risk of equipment failure.

[0016] 3. The reharmonic filtering device for interharmonic mitigation proposed in this solution has a split structure for each of its main components, which is easy to disassemble and replace. In addition, the device itself has no easily damaged electronic components, which reduces the customer's maintenance workload and costs. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the main structure of this utility model;

[0018] Figure 2 This is a flowchart illustrating the operation of this utility model.

[0019] Among them, 1. Filter controller, 2. Filter rheostat, 3. Vacuum contactor, 4. Reactor, and 5. Capacitor.

[0020] The accompanying drawings are provided to further understand the present invention and form part of the specification. They are used together with the embodiments of the present invention to explain the present invention and do not constitute a limitation thereof. Detailed Implementation

[0021] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present utility model. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present utility model without creative effort are within the protection scope of the present utility model.

[0022] like Figure 1 The diagram shown is a schematic representation of the main structure of the resonant filter device of this invention. The device includes a filter controller 1, a filter rheostat 2, a vacuum contactor 3, a reactor 4, and a capacitor 5. The vacuum contactor 3, filter rheostat 2, reactor 4, and capacitor 5 are connected in series to form a filter circuit (primary main wiring structure). Cables are led out from both ends of the reactor 4 and connected to the filter rheostat 2, forming an adjustable filter structure. The output terminal of the filter controller 1 is connected to the control terminal of the vacuum contactor 3 to control the on / off state of the vacuum contactor 3.

[0023] like Figure 2 The diagram shown is a flowchart of the operation of the resonant filter device described in this invention. Its operation process is as follows:

[0024] After the device is started, the filter controller 1 collects the voltage and current signals of the 0.4kV three-phase power supply in real time through the built-in harmonic detection module, and analyzes the frequency and amplitude of interharmonics and higher harmonics.

[0025] When the amplitude of an interharmonic or higher harmonic at a certain frequency exceeds a preset threshold (such as the harmonic limit specified in the national standard), the control module of the filter controller 1 sends a closing command to the vacuum contactor 3.

[0026] After vacuum contactor 3 is closed, the filter circuit is energized, and reactor 4, filter rheostat 2, and capacitor 5 are energized and work. At this time, the circuit forms an initial resonance state, which can filter some harmonics.

[0027] The filter controller 1 calculates the required resonant frequency of the filter circuit based on the detected target harmonic frequency and sends an adjustment signal to the filter rheostat 2. For example, if the target interharmonic frequency is 150Hz (3 times the fundamental frequency 50Hz, not an integer multiple), the resonant frequency of the circuit is reduced to 150Hz by increasing the resistance of the filter rheostat 2, thereby achieving precise filtering.

[0028] The filter controller 1 continuously monitors the power supply harmonic data. If the target harmonic amplitude drops below the threshold, the control vacuum contactor 3 is disconnected and the device stops operating. If the target is not met, the resistance value of the filter rheostat 2 is adjusted until the filtering effect meets the target.

[0029] The present invention and its embodiments have been described above. This description is not restrictive, and the accompanying drawings are only one embodiment of the present invention. The actual method is not limited to this. In conclusion, if a person skilled in the art is inspired by this description and designs a similar structure and embodiment without departing from the inventive spirit of the present invention, such design should fall within the protection scope of the present invention.

Claims

1. A reharmonic filtering device for interharmonic suppression, characterized in that, Includes filter controller, vacuum contactor, filter rheostat, reactor and capacitor; The signal output terminal of the filter controller is connected to the control terminal of the vacuum contactor, and is used to send action commands to the vacuum contactor based on the detected interharmonic and higher harmonic data. The vacuum contactor, filter rheostat, reactor, and capacitor are connected in series to form a filter circuit, and the two ends of the reactor are connected to the filter rheostat to form an adjustable filter structure. The filter circuit is connected to a 0.4kV three-phase power supply, and the filter controller is used to detect interharmonic and higher harmonic data in the 0.4kV three-phase power supply.

2. The apparatus according to claim 1, characterized in that, The filter controller includes a harmonic detection module and a control module. The harmonic detection module is used to acquire voltage and current signals in the 0.4kV three-phase power supply in real time, and analyze them to obtain the frequency and amplitude of interharmonics and higher harmonics. The control module is used to send an on or off command to the vacuum contactor according to the analysis results of the harmonic detection module, and output an adjustment signal to the filter rheostat.

3. The apparatus according to claim 1, characterized in that, The filter rheostat is an adjustable resistor with a resistance adjustment range of 0-100Ω.

4. The apparatus according to claim 1, characterized in that, The capacitor, reactor, vacuum contactor, and filter rheostat are all of a split-type structure.

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