Novel anti-interference ultrahigh frequency partial discharge detection circuit

Abstract

The utility model belongs to the technical field of partial discharge insulation detection, and particularly discloses a novel anti-interference ultrahigh frequency partial discharge detection circuit, which comprises an antenna, a balun circuit and a band elimination filter, the antenna is used for receiving ultrahigh-frequency electromagnetic wave signals generated by partial discharge, the output end of the antenna is connected with the balun circuit, the output end of the balun circuit is connected with the band elimination filter, and the output end of the band elimination filter is integrated with an SMA connector and used for outputting the ultrahigh-frequency electromagnetic wave signals. According to the utility model, the Balun, the band elimination filter and the antenna are placed together, so that partial discharge signals can be effectively received and processed, external interference signals are suppressed, and accurate detection of partial discharge of electrical equipment is realized.

Description

Technical Field

[0001] This utility model belongs to the field of partial discharge insulation detection technology, and specifically relates to a novel anti-interference ultra-high frequency partial discharge detection circuit. Background Technology

[0002] With industrial and urban development, society's demand for electricity is constantly increasing, and the power industry is continuously developing. The safe operation of power transmission and transformation networks has become a key focus of the industry. Insulation faults are common in GIS (Gas Insulated Switchgear) combined electrical equipment, and these faults often manifest as partial discharges. Partial discharges in power equipment severely affect the uniform distribution of the electric field, leading to electric field distortion, corrosion of insulating materials, and ultimately, localized breakdown. When partial discharges occur in the insulation structure, they are accompanied by electrical pulses, ultrasonic waves, electromagnetic radiation, light, chemical reactions, and localized heating.

[0003] When partial discharge occurs inside GIS (Gas Insulated Switchgear) electrical systems, the discharge time is brief, approximately 10ns to 100ns. The rise time is ps, resulting in a wide frequency band for the pulse signal generated by partial discharge. Therefore, the signal excited by partial discharge can be received by a high-frequency sensor, and the received signal can be analyzed to determine the insulation condition of the GIS electrical system. Existing GIS ultra-high frequency sensors are generally broadband. When performing partial discharge detection at GIS basin insulators, the broadband bandwidth of the sensors leads to a large amount of unwanted signals entering the system, reducing system sensitivity. During on-site testing, interference signals are isolated using shielding cloth, which affects the efficiency of live-line testing. Utility Model Content

[0004] The purpose of this invention is to overcome the defects in the existing technology and provide a new type of anti-interference ultra-high frequency partial discharge detection circuit.

[0005] This utility model provides a novel anti-interference ultra-high frequency partial discharge detection circuit, including an antenna, a balun circuit, and a band-stop filter;

[0006] The antenna is used to receive ultra-high frequency electromagnetic wave signals generated by partial discharge, and the output terminal of the antenna is connected to the balun circuit. The output terminal of the balun circuit is connected to the band-stop filter. The output terminal of the band-stop filter integrates an SMA connector for outputting ultra-high frequency electromagnetic wave signals.

[0007] A further embodiment is that the antenna includes a first copper foil and a second copper foil disposed on a plate, with the first copper foil and the second copper foil symmetrically disposed on both sides of the plate.

[0008] A further option is that the board material is 45mm*95mm Rogers RO4003C board material.

[0009] A further embodiment is that the first and second copper foils have the same shape, each including a semi-circular portion and a square portion, which are integrally formed. The diameter of the semi-circular portion and the side length of the square portion are both 25mm. The thickness of the first and second copper foils is 1 / 1 ounce. A signal lead is provided at the top of the semi-circular portion for connection to the balun circuit.

[0010] A further embodiment is that the balun circuit and the band-stop filter are integrated on the substrate, and the balun circuit and the band-stop filter are located on the same side of the substrate as the first copper foil or the second copper foil.

[0011] A further embodiment is that the balun circuit includes a first inductor, a second inductor, a first capacitor, a second capacitor, and a resistor.

[0012] The first inductor and the first capacitor are connected in series to form a first series branch, the second inductor and the second capacitor are connected in series to form a second series branch, and the first series branch and the second series branch are connected in parallel.

[0013] A resistor is connected between the first series branch and the second series branch;

[0014] The input port of the balun circuit is connected to the first copper foil and the second copper foil, and the output port of the balun circuit is connected to the input port of the band-stop filter.

[0015] A further embodiment is that the band-stop filter includes a third inductor to a seventh inductor and a third capacitor to a seventh capacitor; wherein the third capacitor and the third inductor are connected in series, the fourth capacitor and the fourth inductor are connected in series, the fifth capacitor and the fifth inductor are connected in series, the sixth capacitor and the sixth inductor are connected in parallel, the seventh capacitor and the seventh inductor are connected in parallel, and the output port of the band-stop filter is connected to an SMA connector.

[0016] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0017] This invention places the balun and band-stop filter together with the antenna, which can effectively receive and process partial discharge signals while suppressing external interference signals, thus achieving accurate detection of partial discharge in electrical equipment.

[0018] This invention symmetrically arranges two copper foils on both sides of a plate, and then places the balun circuit and band-stop filter on the same side of the plate along with one of the copper foils. This makes full use of space, reduces the size of the detection circuit, and can be used with partial discharge detection equipment from different manufacturers. It also effectively avoids interference, improves detection sensitivity, and thus enhances the efficiency of live-line detection. Attached Figure Description

[0019] The following figures are for illustrative purposes only and are not intended to limit the scope of the present invention.

[0020] Figure 1 : Circuit connection diagram of this utility model;

[0021] In the diagram: 1. Antenna; 2. Balun circuit; 3. Band-stop filter; 4. First copper foil; 5. Second copper foil; 6. First inductor; 7. Second inductor; 8. First capacitor; 9. Second capacitor; 10. Resistor; 11. Third capacitor; 12. Fourth capacitor; 13. Fifth capacitor; 14. Third inductor; 15. Fourth inductor; 16. Fifth inductor; 17. Sixth capacitor; 18. Seventh capacitor; 19. Sixth inductor; 20. Seventh inductor; 21. SMA connector. Detailed Implementation

[0022] To make the objectives, technical solutions, design methods, 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 specific embodiments. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of this utility model.

[0023] like Figure 1 As shown, this utility model provides a novel anti-interference ultra-high frequency partial discharge detection circuit, including an antenna 1, a balun circuit 2, and a band-stop filter 3. The antenna 1 receives ultra-high frequency electromagnetic wave signals generated by partial discharge, and its output is connected to the balun circuit 2. The output of the balun circuit 2 is connected to the band-stop filter 3, converting the unbalanced signal received by the antenna 1 into a balanced signal, which helps reduce common-mode interference and improve signal transmission quality. The balun circuit 2 also plays a role in signal matching, ensuring impedance matching between the antenna 1 and subsequent circuits and reducing signal reflection. The band-stop filter 3 is used to suppress interference signals at specific frequencies, with a band-stop frequency range of 820MHz to 980MHz, and is a 5th-order Butterworth filter. For example, some fixed-frequency interferences in power systems (such as power frequency and its harmonics) can be effectively suppressed by the band-stop filter. By filtering out interference signals, the band-stop filter 3 can improve the purity of the partial discharge signal, making subsequent signal processing and analysis more accurate. An SMA connector 21 is integrated at the output of the band-stop filter 3 for outputting ultra-high frequency electromagnetic wave signals.

[0024] In this embodiment, the antenna 1 includes a first copper foil 4 and a second copper foil 5 disposed on a substrate, symmetrically arranged on both sides of the substrate. The substrate is a 45mm x 95mm Rogers RO4003C substrate. The first copper foil 4 and the second copper foil 5 have identical shapes, each including a semi-circular portion and a square portion, integrally formed. The diameter of the semi-circular portion and the side length of the square are both 25mm. The thickness of the first copper foil 4 and the second copper foil 5 is 1 / 1 ounce, and their area is 12.5 square meters. 2 π / 2 + 25 * 25 = 870.3125 mm 2 A signal lead is provided at the top of the semi-circular portion, which is connected to the balun circuit 2. The balun circuit 2 and the band-stop filter 3 are integrated on the board material, and the balun circuit 2 and the band-stop filter 3 are located on the same side of the board material as the first copper foil 4 or the second copper foil 5. This makes full use of space, reduces the size of the detection circuit, and can be used with partial discharge detection equipment from different manufacturers. It also effectively avoids interference, improves detection sensitivity, and thus improves the efficiency of live-line detection.

[0025] In this embodiment, the balun circuit 2 includes a balun comprising a first inductor 6, a second inductor 7, a first capacitor 8, and a second capacitor 9; the first inductor 6 and the first capacitor 8 are connected in series to form a first series branch, the second inductor 7 and the second capacitor 9 are connected in series to form a second series branch, and the first series branch and the second series branch are connected in parallel; a resistor 10 is connected between the first series branch and the second series branch for impedance matching; the input port of the balun circuit 2 is connected to the first copper foil 4 and the second copper foil 5, and the output port of the balun circuit 2 is connected to the input port of the band-stop filter. The band-stop filter 3 includes a third inductor 14 to a seventh inductor 20 and a third capacitor 11 to a seventh capacitor 18; wherein, the third capacitor 11 and the third inductor 14 are connected in series, the fourth capacitor 12 and the fourth inductor 15 are connected in series, the fifth capacitor 13 and the fifth inductor 16 are connected in series, the sixth capacitor 17 and the sixth inductor 19 are connected in parallel, and the seventh capacitor 18 and the seventh inductor 20 are connected in parallel, and the output port of the band-stop filter 3 is connected to an SMA connector 21 RF connector for connecting external devices.

[0026] The working principle of this utility model is as follows: Antenna 1 is a symmetrical antenna. The antenna impedance composed of the first copper foil 4 and the second copper foil 5 is 220 ohms. The impedance is converted to 50 ohms through the balun circuit 2 for signal transmission. The electromagnetic wave signal received by antenna 1 has a rich frequency component, but some signals are invalid signals. Among them, the communication signal is the signal that the system needs to reject. This signal is filtered out by the band-stop filter 3. The design has an in-band loss of more than 40dB and an out-of-band loss of 1dB, which can effectively improve the detection efficiency. The data is processed at the input end, reducing the data processing pressure of the subsequent system.

[0027] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical applications, or technical improvements to the embodiments in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A novel anti-interference ultra-high frequency partial discharge detection circuit, characterized in that, It includes an antenna (1), a balun circuit (2), and a band-stop filter (3); The antenna (1) is used to receive ultra-high frequency electromagnetic wave signals generated by partial discharge, and the output end of the antenna (1) is connected to the balun circuit (2). The output end of the balun circuit (2) is connected to the band-stop filter (3). The output end of the band-stop filter (3) is integrated with an SMA connector (21) for outputting ultra-high frequency electromagnetic wave signals.

2. The novel anti-interference ultra-high frequency partial discharge detection circuit according to claim 1, characterized in that, The antenna (1) includes a first copper foil (4) and a second copper foil (5) disposed on a plate, the first copper foil (4) and the second copper foil (5) being symmetrically disposed on both sides of the plate.

3. The novel anti-interference ultra-high frequency partial discharge detection circuit according to claim 2, characterized in that, The board material is Rogers RO4003C board material with a diameter of 45mm*95mm.

4. The novel anti-interference ultra-high frequency partial discharge detection circuit according to claim 3, characterized in that, The first copper foil (4) and the second copper foil (5) have the same shape, each including a semicircular part and a square part. The diameter of the semicircular part and the side length of the square part are both 25 mm. The thickness of the first copper foil (4) and the second copper foil (5) is 1 / 1 ounce. A signal lead is provided at the top of the semicircular part and connected to the balun circuit (2).

5. The novel anti-interference ultra-high frequency partial discharge detection circuit according to claim 4, characterized in that, The balun circuit (2) and the band-stop filter (3) are integrated on the substrate, and the balun circuit (2) and the band-stop filter (3) are located on the same side of the substrate as the first copper foil (4) or the second copper foil (5).

6. The novel anti-interference ultra-high frequency partial discharge detection circuit according to claim 2, characterized in that, The balun circuit (2) includes a balun comprising a first inductor (6), a second inductor (7), a first capacitor (8), and a second capacitor (9); The first inductor (6) and the first capacitor (8) are connected in series to form a first series branch, the second inductor (7) and the second capacitor (9) are connected in series to form a second series branch, and the first series branch and the second series branch are connected in parallel. A resistor (10) is connected between the first series branch and the second series branch; The input port of the balun circuit (2) is connected to the first copper foil (4) and the second copper foil (5), and the output port of the balun circuit (2) is connected to the input port of the band-stop filter.

7. The novel anti-interference ultra-high frequency partial discharge detection circuit according to claim 1, characterized in that, The band-stop filter (3) includes a third inductor (14) to a seventh inductor (20) and a third capacitor (11) to a seventh capacitor (18); wherein, the third capacitor (11) and the third inductor (14) are connected in series, the fourth capacitor (12) and the fourth inductor (15) are connected in series, the fifth capacitor (13) and the fifth inductor (16) are connected in series, the sixth capacitor (17) and the sixth inductor (19) are connected in parallel, the seventh capacitor (18) and the seventh inductor (20) are connected in parallel, and the output port of the band-stop filter (3) is connected to an SMA connector (21).

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