CN202616748U - Arc extinguishing device for fault arc detection special for photovoltaic convergence - Google Patents

Abstract

The utility model provides a special fault arc detection arc extinguishing device for photovoltaic confluence, which is characterized in that it includes a first fly-eye lens with a large attenuation characteristic for the arc spectrum and a second fly-eye lens with a broad-spectrum light transmission characteristic. The lens and the second fly-eye lens respectively cover the first photosensitive tube group and the second photosensitive tube group, the first photosensitive tube group only outputs photoelectric signals of scattered sunlight, and the second photosensitive tube group outputs photoelectric signals of scattered sunlight and arc light The output terminals of the first photosensitive tube group and the second photosensitive tube group are connected to the signal topology processing module, and the signal topology processing module outputs the amplified photoelectric signal of the arc light, and the photoelectric signal is the fault arc detection signal. The utility model has the advantages that it can accurately detect the fault arc in the narrow space of the photovoltaic combiner box under the high-voltage DC operating environment, intervene in time to control, cut off the power supply, extinguish the arc, and eliminate the accident.

Description

A special arc fault detection arc extinguishing device for photovoltaic confluence

technical field

The utility model relates to a device for monitoring and extinguishing a high-voltage DC discharge arc in a photovoltaic combiner box.

Background technique

The solar photovoltaic power generation technology of green energy has been widely valued and applied under the multiple pressures of increasing energy depletion and long-term protection of the ecological environment. At present, the photovoltaic power generation industry at home and abroad is showing a trend of rapid development. The photovoltaic lightning protection intelligent combiner box is used in the confluence and distribution facilities of the photovoltaic cell array of the solar power generation system to realize the confluence, monitoring, protection and communication functions of the photovoltaic cell array. It is an important front-end equipment in the photovoltaic power station system facilities.

The photovoltaic combiner box is in the working environment of DC high voltage and high current. The maximum DC voltage on the primary circuit can exceed 880V, and the current single circuit can reach more than 10A. During operation, if the wire end is loose, insulation breakdown, and surface creepage occur, it will discharge and generate continuous high-temperature arc. Photovoltaic power generation is DC high-voltage current. Once an arc occurs, the discharge current has no zero-crossing process, and it is extremely difficult to automatically extinguish the arc without cutting off the power supply. (Unlike the power frequency AC voltage, the current amplitude has one hundred zero-crossing processes per second. When an arc occurs, it is easy to extinguish the arc by itself during the power frequency zero-crossing process.)

When a fault arc occurs, since the arc itself will absorb most of the energy in the circuit and convert it into a high-temperature ionized gas, and it is connected in series in the current loop, the current of the entire loop will be smaller than that during normal operation, and it will not cause short circuit overload protection at all. (such as DC high voltage fuse and DC high voltage circuit breaker) overcurrent protection action. The high-temperature ionized gas transformed by the continuous DC arc will burn cables, electrical equipment and even metal boxes. Not only is the photovoltaic combiner box equipment burned out, but it can also cause regional power outages and even fires, with serious consequences.

In view of the fact that the application sites of photovoltaic arrays and combiner boxes in photovoltaic power stations are mostly in remote mountains and barren slopes with few people, the operation is mostly managed by a small number of people and remote signaling operation mode; accidents of photovoltaic combiner boxes burning due to fault arcs occur from time to time, which poses a threat to the safety of photovoltaic power stations. , Economic power generation brings great hidden dangers and harm.

In order to prevent such accidents, in addition to designing and enhancing the ability of the equipment to resist oxidation damage to the insulation resistance and dirt deterioration to reduce the hotbed of fault arcs, the initial fault arcs can be detected and controlled in time to prevent vicious circles and discharges. Breakdown is the preferred and effective technical means for the development of serious accidents.

The research status of fault arc detection technology at home and abroad is basically aimed at AC power frequency power equipment, and the common solutions are as follows:

1) Voltage detection method: UL standard UL1699 [1] introduces the analysis test method of the average value of AC current and related arc protection products.

2) Pressure detection method: The fault arc detection system developed by Siemens Company by using the pressure effect of the fault arc.

3) Arc detection method: ABB's ARC Guard System is a fault arc detection system consisting of an arc monitor and a current detection unit with dual criteria for arc and current signals.

And other research hotspots of detection methods using arc sound and/or arc light as early warning characteristic signal of arc fault, etc.

Since the combiner box of the photovoltaic array of the photovoltaic power station operates under the condition of DC high voltage power, there is currently no reliable and mature product technology for arc faults in the photovoltaic combiner box in its field.

The above-mentioned voltage detection method cannot detect the fault waveform because the combiner box is a DC voltage waveform; and the pressure detection method is easy to cause missed judgment because the arc fault pressure in the combiner box is lower than the pressure threshold required by the detection device. ABB's ARC fault arc detection system is suitable for open busbar systems, and the interval of arc sensors needs to be 5-6m, so it cannot be applied in the space of 0.07m ³ of photovoltaic combiner boxes.

Contents of the invention

The purpose of the utility model is to provide a device for detecting arc faults that can be applied in a narrow space of a photovoltaic combiner box and is not easy to cause missed judgments.

In order to achieve the above purpose, the technical solution of this utility model is to provide a special arc fault detection and arc extinguishing device for photovoltaic confluence, which is characterized in that it includes a first fly-eye lens with a large attenuation characteristic for the arc spectrum and a broad-spectrum light-transmitting device. characteristics of the second fly-eye lens, the first photosensitive tube group and the second photosensitive tube group are covered by the first fly-eye lens and the second fly-eye lens, the first photosensitive tube group only outputs the photoelectric signal of scattered sunlight, and the second photosensitive tube group group outputs the photoelectric signal of scattered sunlight and arc light, the output terminals of the first photosensitive tube group and the second photosensitive tube group are connected to the signal topology processing module, and the signal topology processing module outputs the photoelectric signal of the amplified arc light, the photoelectric signal It is the fault arc detection signal.

Preferably, the first fly-eye lens and the second fly-eye lens adopt the multi-spherical mirror hemispherical focusing technology to realize wide-angle collection of arc light and scattered sunlight in a small space and short distance.

Preferably, the signal topology processing module includes a first signal amplifying circuit and a second signal amplifying circuit, and the first photosensitive tube group and the second photosensitive tube are respectively connected by the first signal amplifying circuit and the second signal amplifying circuit The photoelectric micro signal output by the group is precisely amplified. The first signal amplifying circuit and the second signal amplifying circuit are respectively connected to the first basic signal correction circuit and the second basic signal correction circuit, and the first basic signal correction circuit and the second basic signal correction circuit The circuits respectively perform basic corrections for the white level of the input signals. The first basic signal correction circuit and the second basic signal correction circuit are connected to the differential amplifier circuit, and the differential amplifier circuit amplifies and corrects the scattered sunlight and arc light The photoelectric signal of the scattered sunlight is offset against the photoelectric signal of the scattered sunlight, so as to output the photoelectric signal of the amplified arc light, which is the fault arc detection signal.

Preferably, the signal topology processing module further includes a filter matching module, the input end of the filter matching module is connected to the output end of the differential amplifier circuit, and its output end is connected to the arc monitoring main unit, which performs balanced filtering on the input signal to remove clutter while matching the output.

The utility model uses the arc light detection technology as a means to solve the detection of the photovoltaic confluence high-voltage DC discharge arc. After the utility model detects the fault arc, it judges and processes it through the main control unit. Switch off, cut off the power supply, and realize arc extinguishing.

The arc light detection technology of the utility model has the following characteristics:

1. The front end of the arc light detector of this utility model is equipped with an array type fly-eye lens, which greatly improves the sensitivity of wavefront detection. The detection of space dead space can more effectively and accurately detect the fault arc occurrence point of different parts of the equipment in the box.

2. This utility model applies differential technology to the design of arc light detector structure, which eliminates the interference of common scattered sunlight on the superimposition of fault arc light, makes fault arc detection more sensitive and correct, and eliminates false alarms of fault arc.

3. Control unit design topology software and hardware technology is based on the characteristics of obvious jumps in arc light, short-circuit current, and color temperature at the moment of arcing, and uses these three arc characterization information as a criterion to set an appropriate amplitude Threshold, establish an early warning system. In addition, control operations are performed with reference to multiple information such as access control. In order to improve the accuracy of fault arc detection and prevent false alarms and missed alarms.

In summary, the utility model has the following advantages: it can accurately detect the fault arc in the narrow space of the photovoltaic combiner box under the high-voltage DC operating environment, intervene in time to control, cut off the power supply, extinguish the arc, and eliminate the accident.

Description of drawings

Fig. 1 is a schematic diagram of a photovoltaic confluence dedicated fault arc detection and arc extinguishing device in an embodiment;

Fig. 2 is a schematic diagram of the application of a special arc fault detection and arc extinguishing device for photovoltaic confluence;

Fig. 3 is a block diagram of a signal topology processing module.

Detailed ways

In order to make the utility model more comprehensible, preferred embodiments are described in detail below with accompanying drawings.

As shown in FIG. 1 , this embodiment discloses a fault arc detection and arc extinguishing device dedicated to photovoltaic confluence, including a first fly-eye lens 1 and a second fly-eye lens 2 . Among them, the first fly-eye lens 1 has channel spectrum light transmission characteristics, that is, scattered sunlight can pass through the lens, but has a large attenuation characteristic for the arc spectrum; the second fly-eye lens 2 has broad-spectrum light transmission characteristics, that is, it can scatter sunlight and arc light. can pass through the lens. The first fly-eye lens 1 and the second fly-eye lens 2 use bionic fly-eye technology, and adopt the method of multi-spherical mirror hemispherical focusing to realize wide-angle collection of short-distance arc light in a small space.

The first fly-eye lens 1 and the second fly-eye lens 2 are respectively covered on the first photosensitive tube group 3 and the second photosensitive tube group 4. Due to the difference in light transmission characteristics of the first fly-eye lens 1 and the second fly-eye lens 2, the first The photosensitive tube group 3 only outputs photoelectric signals of scattered sunlight, and the second photosensitive tube group 4 outputs photoelectric signals of scattered sunlight and arc light. The output ends of the first photosensitive tube group 3 and the second photosensitive tube group 4 are connected to the signal topology processing module, and the signal topology processing module outputs the amplified photoelectric signal of the arc light, which is the fault arc detection signal.

As shown in Figure 3, the signal topology processing module includes a first signal amplifying circuit and a second signal amplifying circuit, and the first photosensitive tube group 3 and the second The photoelectric micro signal output by the photosensitive tube group 4 is precisely amplified, and the first signal amplifying circuit and the second signal amplifying circuit are respectively connected to the first basic signal correction circuit and the second basic signal correction circuit, and the first basic signal correction circuit and the second The basic signal correction circuit respectively performs basic correction for the white level of the input signal. The first basic signal correction circuit and the second basic signal correction circuit are connected to the differential amplifier circuit, and the differential amplifier circuit amplifies and corrects the scattered sunlight And the photoelectric signal of the arc light is offset with the photoelectric signal of the scattered sunlight, so as to output the amplified photoelectric signal of the arc light. The arc monitoring main unit at the end matches, and the photoelectric signal is the fault arc detection signal.

The application schematic diagram of the above device is shown in Figure 2, wherein the output generated by the photovoltaic panel array 5 is combined and then controlled by the high-voltage DC circuit breaker in the photovoltaic combiner box to obtain the photovoltaic combined output 6, which is detected by the DC current Hall detection module The current in the photovoltaic combiner box transmits the detection signal to the arc monitoring main unit. At the same time, the arc monitoring main unit also receives signals from other sensors 8 (such as access control sensors) located in the photovoltaic combiner box. The above-mentioned special arc fault detection and arc extinguishing device 7 for photovoltaic confluence is placed in the photovoltaic confluence box, and its output signal is also transmitted to the arc monitoring main unit. When the fault arc detection and arc extinguishing device 7 dedicated to photovoltaic confluence detects the occurrence of a fault arc, it outputs a control signal to the high-voltage DC circuit breaker to open the gate after multiple judgments by the arc monitoring main unit, cut off the power supply, extinguish the arc, eliminate the fault and send a remote signal Call the police.

Claims (4)

1. a photovoltaic special-purpose fault electric arc that confluxes is surveyed arc-control device; It is characterized in that: comprise that arc spectrum is had than first fly's-eye lens (1) of high attenuation characteristic and possesses second fly's-eye lens (2) of wide spectrum light transmission features; Respectively the first photosensitive tube group (3) and the second photosensitive tube group (4) are covered by first fly's-eye lens (1) and second fly's-eye lens (2); The first photosensitive tube group (3) is only exported the photosignal of scattering daylight; The second photosensitive tube group (4) is then exported the photosignal of scattering daylight and arclight; The output of the first photosensitive tube group (3) and the second photosensitive tube group (4) connects signal topology processing module, the photosignal of the arclight after amplifying by the output of signal topology processing module, and this photosignal is the fault electric arc detectable signal.

2. conflux special-purpose fault electric arc of a kind of photovoltaic as claimed in claim 1 is surveyed arc-control device; It is characterized in that: said first fly's-eye lens (1) and said second fly's-eye lens (2) adopt many spherical mirrors hemisphere focusing technology, and the arclight and the scattering daylight of little space low coverage are realized the wide-angle collection.

3. conflux special-purpose fault electric arc of a kind of photovoltaic as claimed in claim 1 is surveyed arc-control device; It is characterized in that: said signal topology processing module comprises first signal amplification circuit and secondary signal amplifying circuit; Respectively the photoelectricity micro-signal of said first photosensitive tube group (3) and the output of the said second photosensitive tube group (4) is carried out the precision amplification by first signal amplification circuit and secondary signal amplifying circuit; First signal amplification circuit and secondary signal amplifying circuit connect the first basis signal circuit for rectifying and the second basis signal circuit for rectifying respectively; Respectively the signal of input is directed against the basis rectification of white level by the first basis signal circuit for rectifying and the second basis signal circuit for rectifying; The first basis signal circuit for rectifying and the second basis signal circuit for rectifying connect differential amplifier circuit; The scattering daylight after will being amplified and correct by differential amplifier circuit and the photosignal of arclight and the photosignal of scattering daylight offset; Thereby export the photosignal of the arclight after the said amplification, this photosignal is the fault electric arc detectable signal.

4. conflux special-purpose fault electric arc of a kind of photovoltaic as claimed in claim 3 is surveyed arc-control device; It is characterized in that: said signal topology processing module also comprises the filtering matching module; The input of filtering matching module connects the output of said differential amplifier circuit; Its output connects the arc monitor master unit, carries out balance filtering to remove clutter by its signal to input, is complementary with output simultaneously.

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