Arc light protection pre-alarm system of medium and low voltage switch cabinet

Abstract

The utility model provides an arc light protection pre-alarm system of a middle and low voltage switch cabinet. The arc light protection pre-alarm system comprises an arc discharge generating device, a sensor, a signal conditioning device and a computer. According to the arc light protection pre-alarm system of the middle and low voltage switch cabinet, arc light, arc sound and over-current signals generated by the arc discharge generation device are respectively and simultaneously collected, and signals capable of representing essential characteristics can be found out at a computer end; the arc sound signal is used as an early warning signal for generating a fault arc, the arc light and the current signal are used as an alarm protection signal for generating the fault arc, the signals are monitored, and the early warning signal is sent out before abnormity occurs in the switch but arcing is not generated, so that the fault arc is choked and killed in a cradle; in other words, the detection is started when the electric arc occurs, the traditional passive mode is changed into the active mode, precious time is bought for workers to find and eliminate faults in time, and possible losses are reduced to the minimum.

Description

Technical Field

[0001] The utility model relates to the technical field of switch cabinets, and specifically discloses an arc protection pre-alarm system for medium and low voltage switch cabinets. Background Art

[0002] With the increasingly widespread application of complete sets of switchgear in medium and low voltage power distribution systems, arc faults in medium and low voltage busbars occur frequently due to various factors such as equipment reasons and operating environment. Arc faults in medium and low voltage busbars are characterized by rapid development, unpredictability, and great destructive power, which can cause serious consequences such as burning of switchgear or even explosion. However, there is still no busbar protection specifically for medium and low voltage switchgear. Therefore, the development of a high-speed and effective arc fault protection system is imminent.

[0003] The method of switchgear arc detection is as follows:

[0004] (1) Voltage and current detection method

[0005] When an arc fault occurs inside a medium- and low-voltage distribution cabinet, the voltage and current on the related lines will also change accordingly. Figure 2 This is the detection principle structure diagram of AFCI.

[0006] (2) Arc detection method

[0007] The arc light spectrum emitted during arcing is used as the characteristic signal, and combined with the short-circuit current signal to detect arc faults. Figure 3 This is the detection principle diagram of VAMP.

[0008] (3) Ultraviolet characteristics detection method

[0009] Arc discharge generates radiation, and the radiation spectrum includes three regions: ultraviolet, visible light, and near-infrared. Among these three regions, the ultraviolet region has the highest radiation intensity. Analysis of the spectrum of corona discharge shows that the wavelength of ultraviolet light is between 230 and 400 nm, among which a small part of the wavelength is within the range of 230 to 280 nm, which is usually called the "solar blind region". Therefore, in order to reduce the interference of visible light during arc discharge detection, the solar blind region can be used to monitor arc faults, that is, the arc ultraviolet characteristic detection method, which also belongs to the arc light detection method. Figure 4 This is the structural block diagram of the arc ultraviolet detection method.

[0010] At present, some finished arc protection systems have been developed both at home and abroad, but most of them use one or both of the arc signal and the short-circuit current signal generated after the arc occurs as the basis for protection action. This method is relatively passive. Although it can quickly cut off the fault, it often causes certain losses. Utility Model Content

[0011] In view of the above-mentioned defects or deficiencies in the prior art, the present application aims to provide a medium and low voltage switch cabinet arc protection early warning system, wherein the medium and low voltage switch cabinet arc protection early warning system comprises an arc discharge generating device, a sensor, a signal conditioning device and a computer, wherein the sensor is electrically connected to the arc discharge generating device and the computer respectively, and the signal conditioning device is electrically connected to the arc discharge generating device and the computer respectively.

[0012] Preferably, the sensors include an arc light sensor, a current sensor and an arc sound sensor installed inside the arc discharge generating device.

[0013] Preferably, the medium and low voltage switch cabinet arc protection early warning system extracts arc sound signals based on wavelet and wavelet packet analysis theory, feature extraction technology and pattern recognition technology.

[0014] Beneficial effects:

[0015] 1. The arc protection pre-alarm system of the medium and low voltage switch cabinet can simultaneously collect the arc light, arc sound and overcurrent signals generated by the arc discharge generating device, and find out the signals that can characterize their essential characteristics on the computer side, and then use the arc sound signal as the early warning signal of the fault arc, and the arc light and current signals as the alarm protection signal of the fault arc, and monitor the signal, and then send out an early warning signal before the abnormality occurs inside the switch but the arc is not generated, so as to nip the fault arc in the bud. That is to say, the detection starts before the arc occurs, changing the traditional passive to active, so as to buy precious time for the staff to find and eliminate the fault in time, and minimize the possible losses.

[0016] 2. The arc protection early warning system of the medium and low voltage switch cabinet can effectively extract the required characteristic arc sound signal through the feature extraction technology based on wavelet and wavelet packet analysis theory. This early warning technology based on a certain characteristic quantity is also the focus of the current research on the arc protection system of medium and low voltage switch cabinets. It is of great significance to minimize the time of fault removal and reduce losses. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Other features, objects and advantages of the present application will become more apparent by reading the detailed description of non-limiting embodiments made with reference to the following drawings:

[0018] Figure 1 It is a schematic diagram of the structure of the utility model;

[0019] Figure 2 This is the structure diagram of the detection principle of AFCI;

[0020] Figure 3 This is the detection principle diagram of VAMP;

[0021] Figure 4 This is the structural block diagram of the arc ultraviolet detection method.

[0022] In the figure: 1. Arc discharge generating device; 2. Sensor; 3. Signal conditioning device; 4. Computer. DETAILED DESCRIPTION

[0023] The present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the relevant utility model, rather than to limit the utility model. It is also necessary to explain that, for ease of description, only the parts related to the utility model are shown in the accompanying drawings.

[0024] The accompanying drawings in the embodiments of the present invention: different types of section lines in the drawings are not marked according to national standards, nor do they impose any requirements on the materials of the components. Instead, they are used to distinguish the cross-sectional views of the components in the drawings.

[0025] See also Figure 1 A medium and low voltage switch cabinet arc protection early warning system, the medium and low voltage switch cabinet arc protection early warning system comprises an arc discharge generating device 1, a sensor sensor 2, a signal conditioning device 3 and a computer 4, the sensor sensor 2 is electrically connected to the arc discharge generating device 1 and the computer 4 respectively, the signal conditioning device 3 is electrically connected to the arc discharge generating device 1 and the computer 4 respectively, and the signal conditioning device 3 can be controlled by the computer 4 to enable the inner side of the arc discharge generating device 1 to generate arc light, arc sound and overcurrent signals under different experimental conditions, so as to obtain arc discharge data of the medium and low voltage switch cabinet under different working conditions.

[0026] Among them, the sensor 2 includes an arc sensor, a current sensor and an arc sound sensor installed on the inside of the arc discharge generating device 1. Through the coordinated use of the arc sensor, the current sensor and the arc sound sensor, the sensor 2 can detect and collect the arc light, arc sound and overcurrent signals generated inside the arc discharge generating device 1 respectively.

[0027] Among them, the arc protection early warning system of medium and low voltage switchgear extracts arc sound signals based on wavelet and wavelet packet analysis theory, feature extraction technology and pattern recognition technology.

[0028] Among them, the arc protection early warning system of medium and low voltage switch cabinets includes the following steps:

[0029] S1. Firstly, aiming at the problem of feature extraction in a strong noise environment, the wavelet and wavelet packet analysis theory, feature extraction technology and pattern recognition technology were studied, and the key point was how to use wavelet packet transform and fuzzy bubble mean clustering algorithm to extract the feature of arc sound signal and perform pattern recognition;

[0030] S2. An arc discharge generating device 1, a sensor 2, a signal conditioning device 3 and a computer 4 are used to form a fault arc detection system capable of simulating various types of arc discharges, collect arc light, arc sound and overcurrent signals under different experimental conditions, analyze them from the time domain and frequency domain, find the internal connection of these three signals and the change law during the discharge process, so as to determine that the arc sound signal is used as a warning signal for the generation of a fault arc, and the arc light and current signals are used as alarm protection signals for the generation of a fault arc;

[0031] S3. Based on the excellent localization capability of wavelet packet analysis in the time and frequency domain, and the ability to further divide the signal into multiple scales within the full frequency band, the method of three-layer wavelet packet decomposition of the signal is adopted to extract the characteristic quantity that can characterize the essential change of the arc sound signal, and a pattern recognition system based on the fuzzy bubble mean clustering algorithm is established to train and test the characteristic quantity of the arc sound signal;

[0032] S4. Designed an arc protection early warning system based on DSP, performed hardware and software design on it, and verified the feasibility of the system.

[0033] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0034] The above description is only a preferred embodiment of the present application and an explanation of the technical principles used. Those skilled in the art should understand that the scope of the utility model involved in the present application is not limited to the technical solution formed by a specific combination of the above technical features, but should also cover other technical solutions formed by any combination of the above technical features or their equivalent features without departing from the concept of the utility model. For example, the above features are replaced with the technical features with similar functions disclosed in the present application (but not limited to) by each other to form a technical solution.

Claims

1. A medium and low voltage switch cabinet arc protection early warning system, characterized in that: The medium and low voltage switch cabinet arc protection early warning system comprises an arc discharge generating device (1), a sensor (2), a signal conditioning device (3) and a computer (4), wherein the sensor (2) is electrically connected to the arc discharge generating device (1) and the computer (4), and the signal conditioning device (3) is electrically connected to the arc discharge generating device (1) and the computer (4).

2. The arc protection early warning system for medium and low voltage switch cabinet according to claim 1 is characterized in that: The sensor (2) comprises an arc light sensor, a current sensor and an arc sound sensor which are installed inside the arc discharge generating device (1).

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