Switch cabinet arc detection system based on fluorescent optical fiber

Abstract

The invention relates to a switch cabinet arc detection system based on fluorescent optical fibers, and aims to improve the efficiency and accuracy of switch cabinet arc monitoring in an electric power system. The system is characterized in that the system comprises a host module, a photoelectric conversion module and an optical fiber sensing detection unit, simultaneous detection of multiple switch cabinet arcs can be realized, the detection time is less than 2.5 ms, and the sensitivity and reliability of arc detection are significantly improved. Besides, the system also provides a rapid electric quantity protection algorithm, and a high-reliability arc light rapid protection device with protection action time of 3-5ms is developed by combining voltage, current and arc light comprehensive criteria, so that the problem of rapid clearing of arc light discharge faults is effectively solved. The arc detection system has the advantages of being low in cost, easy to maintain, high in environmental adaptability and the like, and is suitable for arc monitoring in the high-voltage switch cabinet.

Description

Technical Field

[0001] The present invention relates to the technical field of switch cabinet arc monitoring, and in particular to a switch cabinet arc monitoring system based on fluorescent optical fiber. Background Art

[0002] As a key equipment in the power system, the safe and stable operation of the switch cabinet is crucial to the reliability of the entire power system. However, during the operation of the switch cabinet, arcs may be generated due to various reasons, such as equipment aging, improper operation or external environmental factors. Arcs not only cause equipment damage, but may also cause fires, posing a serious threat to personnel safety and property safety. At present, arc detection mainly relies on traditional technical means, such as temperature sensors, pressure sensors or ultrasonic sensors. Although these methods can realize arc detection to a certain extent, they have many limitations. For example, the response time of the temperature sensor is long and it is impossible to capture the moment of arc generation in real time; the pressure sensor may be affected by environmental noise, resulting in false alarms; and the ultrasonic sensor may have a poor detection effect due to the complex internal structure of the switch cabinet and the obstruction of sound signal transmission. In addition, the existing detection system often requires complex wiring and maintenance, which increases the installation cost and maintenance difficulty of the system. In some special environments, such as places with high humidity or strong electromagnetic interference, the performance of the existing detection system will also be affected. In view of the above problems, the present invention proposes a new arc detection technology that can provide fast, accurate and reliable detection results, while having good environmental adaptability and low maintenance cost. The arc detection technology proposed in the present invention is based on fluorescent optical fiber and photomultiplier tube (SiPM), and has the following advantages over traditional switch cabinet arc detection methods: (1) Fast sensing speed and high sensitivity. The switch cabinet arc monitoring system based on fluorescent optical fiber belongs to the optical measurement method. The signal propagation speed is close to the speed of light and can respond to the arc fault inside the switch cabinet in time. (2) Anti-interference and no false alarm. The switch cabinet arc monitoring system uses a special fluorescent optical fiber, which only detects the ultraviolet band part of the arc and is not sensitive to ambient light; (3) The detection range is wide and multiple switch cabinet arcs can be detected simultaneously. The switch cabinet arc detection method proposed by the present invention uses a silicon photomultiplier (SiPM) at the end of the fluorescent optical fiber for photoelectric conversion. The SiPM detection limit is extremely low and can be used for single photon counting, thus expanding the detection range of the method; (4) Simple structure, easy and flexible layout and maintenance. The arc monitoring system proposed in the present invention is based on fluorescent optical fiber sensing, which can be flexibly arranged at a position inside the switch cabinet where arc light can be easily detected, and is easy to install and disassemble.

[0003] After searching, the patent publication number CN110649575A discloses a switch cabinet arc protection device based on ultraviolet light detection, including an arc protection module, an ultrasonic detection module and a single-chip microcomputer; the arc protection module is connected to the single-chip microcomputer, the ultrasonic detection module includes an ultrasonic sensor, an amplifier circuit, a filter circuit and a comparison circuit, the ultrasonic sensor is connected to the amplifier circuit, the amplifier circuit is connected to the filter circuit, the filter circuit is connected to the comparison circuit, and the comparison circuit is connected to the single-chip microcomputer. The device sets an ultrasonic detection module so that it cooperates with the arc protection module to detect potential arc faults in the switch cabinet and issue an alarm. However, the ultraviolet light sensor used in the patent is large in size, and it is difficult to use and maintain in a switch cabinet with limited space. At the same time, the ultraviolet light sensor is expensive and can only monitor single-sided switch cabinets, and cannot achieve distributed detection of multi-sided switch cabinets.

[0004] After searching, the patent publication number CN115372765A discloses a method for detecting unstable arc faults based on zero-sequence energy mutation. First, obtain the zero-sequence current signal. Determine the polarity of the zero-sequence current. Extract the zero-sequence current at an interval of half a power frequency cycle after the fault. Obtain the zero-sequence energy curve after different types of faults occur in the line, and collect a 1ms time window to calculate the energy mutation amount of two adjacent points. Use the energy mutation amount and the threshold discriminant to discriminate the line arc fault. When the mutation amount is greater than or equal to the threshold Em, it is considered that an unstable arc fault has occurred. If it is less than the threshold Em, it is determined that no fault has occurred. This invention can realize switch cabinet fault detection. However, the zero-sequence current signal in the arc detection in the switch cabinet is easily affected by electromagnetic interference, resulting in false alarms.

[0005] The switch cabinet arc detection method proposed in the present invention detects the switch cabinet arc based on fluorescent optical fiber, uses silicon photomultiplier tubes (SiPM) for photoelectric conversion, and uses a host system to perform logical judgment on the arc signal, which can achieve distributed arc detection of up to 10 switch cabinets.

[0006] The switch cabinet arc detection system based on fluorescent optical fiber belongs to the optical measurement method, the signal propagation speed is close to the speed of light, the arc detection response is less than 50μs, and the switch cabinet internal arc fault can be quickly monitored.

[0007] The switch cabinet arc detection system based on fluorescent optical fiber uses a special fluorescent optical fiber, which is only sensitive to the ultraviolet band (<380nm) of the arc light, not sensitive to ambient light, and is not prone to false operation.

[0008] The fluorescent optical fiber of the switch cabinet arc detection system based on fluorescent optical fiber is arranged on the inner wall of the busbar room and the cable room of the switch cabinet, which is easy to install and disassemble, has a simple structure, and is convenient and flexible to arrange and maintain. Summary of the invention

[0009] The present invention is based on the essential physical phenomenon that the switch cabinet arc generates light signals. In order to overcome the defects of the prior art, a switch cabinet arc detection system based on fluorescent optical fiber is provided, which is expected to realize distributed detection of switch cabinet arc light.

[0010] The purpose of the present invention can be achieved through the following technical solutions: a switch cabinet arc detection system based on fluorescent optical fiber, a fluorescent optical fiber is arranged in series inside a multi-sided switch cabinet, and the switch cabinet arc detection is realized through the optical signal of the arc.

[0011] The arc detection system comprises a host module, a photoelectric conversion module and an optical fiber sensing detection unit.

[0012] The host module described herein functions as a logic judgement, generating judgment criteria from the signal of the arc detection system.

[0013] The photoelectric conversion module includes a 28V DC bias power supply, a silicon photomultiplier (SiPM), and an I / V conversion circuit.

[0014] The I / V conversion circuit includes a 50Ω DC resistor and a 10μF coupling capacitor, which is used to convert the photocurrent signal of the SiPM into a voltage signal.

[0015] The optical fiber sensing unit includes a plastic transmission optical fiber and a fluorescent optical fiber. The core material of the plastic transmission optical fiber is PS, the cladding material is PMMA, the optical fiber diameter is 1mm, and the light transmission attenuation is 1dB / m. The core material of the fluorescent optical fiber is PS, the cladding material is PMMA, the optical fiber diameter is 1mm, the light transmission attenuation is 0.4dB / m, the absorption spectrum wavelength peak is 351nm, and the emission spectrum range wavelength peak is 450nm.

[0016] The host system and the photoelectric conversion module are installed in the secondary room of the switch cabinet. The sensor module is arranged in the busbar room and the cable room of the switch cabinet, and the fluorescent optical fiber is arranged through the optical fiber hole through the multi-faceted switch cabinet. The first section of the fluorescent optical fiber is connected to the plastic transmission optical fiber, and the plastic transmission optical fiber is connected to the photoelectric conversion module.

[0017] The negative electrode of the SiPM in the photoelectric conversion unit is connected to a 28V DC bias power supply, and the positive electrode of the SiPM is connected to an I / V conversion circuit (205).

[0018] Furthermore, the 50Ω DC resistor in the I / V conversion circuit converts the photocurrent signal into a voltage signal, and the 10μF coupling capacitor is used to filter out DC bias power supply noise.

[0019] The distributed arc detection system based on fluorescent optical fiber is characterized in that the fluorescent optical fiber (304) excites a fluorescent signal with a peak wavelength of 450 nm after receiving the arc signal.

[0020] Furthermore, the fluorescent signal enters the plastic transmission optical fiber (303) after being output from the fluorescent light, and reaches the secondary chamber (302) of the first-stage switch cabinet after passing through the plastic transmission optical fiber (303). The fluorescent signal outputs a voltage signal through the photoelectric conversion module (102), and the voltage signal enters the host system (101) for logic judgment.

[0021] Compared with the existing technology, the switch cabinet arc detection system based on fluorescent fiber has significant advantages. First, fluorescent fiber has extremely high sensitivity and fast response capability, and can respond quickly in the initial stage of the arc, ensuring that the system detects the signal within 50μs, significantly improving the fault response speed. Secondly, fluorescent fiber has excellent anti-electromagnetic interference ability, and can still work stably under high-voltage environment, avoiding the common signal distortion and false triggering problems in traditional technology. In addition, fluorescent fiber is insensitive to external light, which effectively avoids misjudgment caused by changes in light. Its good insulation and high temperature resistance and corrosion resistance enable the system to operate stably for a long time in harsh environments. Finally, the fluorescent fiber has little effect on the electric field, avoiding the problem of electric field distortion and ensuring the accuracy of the signal. In general, the arc detection system based on fluorescent fiber has obvious advantages in improving detection accuracy, response speed, stability and anti-interference, and is an efficient and reliable switch cabinet arc detection solution. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 The figure is a logic diagram of a switch cabinet arc monitoring system based on fluorescent optical fiber, wherein 101 is a host system, 102 is a photoelectric conversion unit, and 103 is a sensor unit.

[0023] Figure 2 The circuit diagram of the photoelectric conversion unit of the switch cabinet arc monitoring system based on fluorescent optical fiber is shown in FIG. 201 is a DC bias power supply, 202 is a silicon photomultiplier tube (SiPM), 203 is a 50Ω DC resistor, 204 is a 10μF coupling capacitor, and 205 is an I / V conversion circuit.

[0024] Figure 3 The schematic diagram of the arrangement and installation of fluorescent optical fibers in 10 switch cabinets in a switch cabinet arc monitoring system based on fluorescent optical fibers is shown in FIG. 301 is an arc protection device, 302 is a secondary chamber, 303 is a plastic transmission optical fiber, 304 is a fluorescent optical fiber, 305 is an optical fiber hole, 306 is a busbar chamber, and 307 is a cable chamber. Specific implementation plan The embodiments are described in detail below in conjunction with the accompanying drawings.

[0025] In order to more clearly explain the objectives, technical solutions and advantages of this patent application, the following content will describe this application in detail with reference to the accompanying drawings and examples. It should be noted that the embodiments described herein are only used to explain the contents of this application and do not constitute any limitation to this application. Any other implementation methods obtained by any person skilled in the art according to this application without performing creative work shall be deemed as the scope of protection covered by this application.

[0026] The drawings mentioned in the text only show some examples or implementations of the present patent application. For those of ordinary skill in the art, they can apply the principles of the present application to other similar situations based on these drawings without performing creative work. At the same time, it should also be recognized that although complex efforts may be required during the development process, for those of ordinary skill in the art, the adjustments and changes in design, manufacturing or production based on the technical content disclosed in the present application are merely routine technical operations and should not be regarded as incompleteness of the disclosure of the present application.

[0027] The switch cabinet arc detection system based on fluorescent optical fiber proposed by the present invention is composed of a host system (101), a photoelectric conversion unit (102), and a sensor unit (103). The photoelectric conversion unit (102) is composed of a DC bias power supply (201), a silicon photomultiplier tube (SiPM) (202), a 50Ω DC resistor (203), a 10μF coupling capacitor (204), and an I / V conversion circuit (205); the sensor unit (103) is composed of a plastic transmission optical fiber (303) and a fluorescent optical fiber (304).

[0028] Example 1: Figure 2 The schematic diagram of the arc detection device for a switch cabinet based on fluorescent optical fiber is shown, and the installation instructions of the present invention are provided. The photoelectric element in the photoelectric conversion device is a silicon photomultiplier tube (SiPM) (202), and the photosensitive area of ​​the silicon photomultiplier tube (202) is 9mm 2 , peak response wavelength is 420nm, dark count rate is 140kHz / mm 2 In the circuit board, the negative electrode of the silicon photomultiplier tube (202) is connected to a 28V DC bias power supply (201), and the positive electrode is connected to an I / V conversion circuit (205). A 50Ω DC resistor (203) in the I / V conversion circuit (205) converts a photocurrent signal into a voltage signal, and a 10μF coupling capacitor (204) is used to filter out DC bias power supply noise (201).

[0029] Example 2: Figure 3The structure diagram of the optical fiber sensing system of the present invention is shown, and the installation instructions of the present invention are provided. The optical fiber sensing unit (103) includes a plastic optical fiber (303) and a fluorescent optical fiber (304). First, the fluorescent optical fiber (304) is arranged in the high-voltage switch cabinet. The core material of the fluorescent optical fiber (304) is PS, the cladding material is PMMA, the optical fiber diameter is 1mm, the light transmission attenuation is 0.4dB / m, the absorption spectrum wavelength peak is 351nm, and the emission spectrum range is a wavelength peak of 450nm. A fluorescent optical fiber is passed through the busbar room (306) and the cable room (307) arranged in the 10-sided switch cabinet as shown in the figure, and the optical fiber is connected between the switch cabinets through the optical fiber hole (305). The fluorescent optical fiber passes through the switch cabinet casing and the internal structure part with a black corrugated tube protection, and the part passing through the box body is protected with a plastic sleeve.

[0030] The optical signal outside the switch cabinet busbar room (306) and the cable room (307) is transmitted using a plastic optical fiber (303), and the first section of the fluorescent optical fiber (304) is connected to the plastic optical fiber (303). The plastic optical fiber (303) is connected to the photoelectric conversion device using an optical fiber flange. The plastic optical fiber (303) has a diameter of 1 mm and a numerical aperture (NA) of 0.5, which matches the fluorescent optical fiber (304) and is covered with a black sheath.

[0031] Furthermore, the photoelectric conversion device is connected to the host system, and the host system is connected to the display screen and the alarm. The host system processes the received signal, the display screen displays the operating status of each high-voltage switch cabinet in real time, and the alarm sends an alarm signal when the alarm information is received.

Claims

1. A distributed arc detection system based on fluorescent optical fiber, characterized in that: The system is composed of a host module (101), a photoelectric conversion unit (102), an optical fiber sensing detection unit (103), a DC bias power supply (201), a silicon photomultiplier tube (SiPM) (202), an I / V conversion circuit (205), a DC resistor (203), a coupling capacitor (204), a plastic transmission optical fiber (303), and a fluorescent optical fiber (304).

2. A distributed arc detection system based on fluorescent optical fiber according to claim 1, characterized in that: in, The host module (101) functions as a logic judgement, generating judgment criteria from the signal of the arc detection system.

3. A distributed arc detection system based on fluorescent optical fiber according to claim 1, characterized in that: The photoelectric conversion unit (102) comprises a DC bias power supply (201), a silicon photomultiplier (SiPM) (202), and an I / V conversion circuit (205). The DC bias power supply is 28V and is powered by a lithium battery. The SiPM photosensitive area is 9mm 2 , peak response wavelength is 420nm, dark count rate is 140kHz / mm 2 The I / V conversion circuit (205) comprises a 50Ω DC resistor and a 10μF coupling capacitor, and is used to convert the photocurrent signal of the SiPM into a voltage signal.

4. A distributed arc detection system based on fluorescent optical fiber according to claim 1, characterized in that: The optical fiber sensing detection unit (103) comprises a plastic transmission optical fiber (303) and a fluorescent optical fiber (304). The core material of the plastic transmission optical fiber (303) is PS, the cladding material is PMMA, the optical fiber diameter is 1 mm, and the light transmission attenuation is 1 dB / m. The core material of the fluorescent optical fiber (304) is PS, the cladding material is PMMA, the optical fiber diameter is 1 mm, the light transmission attenuation is 0.4 dB / m, the absorption spectrum wavelength peak is 351 nm, and the emission spectrum range is a wavelength peak of 450 nm.

5. The distributed arc detection system based on fluorescent optical fiber according to claim 1, characterized in that: The arc protection device (301) is installed in the secondary chamber (302) of the switch cabinet, and comprises a host system (101) and a photoelectric conversion unit (102).

6. A distributed arc detection system based on fluorescent optical fiber according to claim 1, characterized in that: The negative electrode of the SiPM (202) in the photoelectric conversion unit (102) is connected to a 28V DC bias power supply (201), and the positive electrode of the SiPM (202) is connected to an I / V conversion circuit (205). The 50Ω DC resistor (203) in the I / V conversion circuit (205) converts the photocurrent signal into a voltage signal, and the 10μF coupling capacitor (204) is used to filter out the DC bias power supply noise (201).

7. A distributed arc detection system based on fluorescent optical fiber according to claim 1, characterized in that: The fluorescent optical fiber (304) in the sensing unit (103) is arranged through the multi-faceted switch cabinet, and is mainly arranged in the busbar room (306) and the cable room (307) of the switch cabinet. The plastic transmission optical fiber (303) is used to transmit the light in the fluorescent optical fiber to the arc protection device (301), and is arranged between the cable room (307) and the secondary room (302) of the switch cabinet.

8. The distributed arc detection system based on fluorescent optical fiber according to claim 1, characterized in that: The head end of the fluorescent optical fiber (304) is connected to the plastic transmission through the optical fiber flange, and then arranged in a surrounding manner in the switch cabinet. First, it passes through the optical fiber hole (305) on the side panel of the busbar chamber (306) of the parallel switch cabinet, and is connected from the busbar chamber (306) to the cable chamber (307) in the end switch cabinet. Then, it passes through the optical fiber hole (305) on the side panel of the cable chamber (307).

9. A distributed arc detection system based on fluorescent optical fiber according to claim 1, characterized in that: After receiving the arc light signal, the fluorescent optical fiber (304) excites a fluorescent signal with a peak wavelength of 450 nm. The fluorescent signal enters the plastic transmission optical fiber (303) after being output from the fluorescent light, and reaches the secondary chamber (302) of the first-stage switch cabinet after passing through the plastic transmission optical fiber (303). The fluorescent signal outputs a voltage signal through the photoelectric conversion module (102), and the voltage signal enters the host system (101) for logic judgment.

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