Fault arc detection device for photovoltaic power generation equipment

Abstract

The utility model discloses a photovoltaic power generation equipment fault arc detection device comprising a current detection instrument, the current detection instrument is connected in series with a detection current adding device and a current regulator, two ends of the current detection instrument after series connection are respectively connected to corresponding output ends of a photovoltaic string to be detected to form a photovoltaic string anti-current detection loop, and the detection current adding device comprises a DC power supply. A constant-current constant-voltage module connected with the direct-current power supply is further arranged in the detection current adding device, and the two ends of the current detection instrument connected with the current regulator in series are also connected to the corresponding output ends of the photovoltaic string to be detected respectively to form a photovoltaic string short-circuit current detection loop. And the photovoltaic group string short-circuit current detection loop and the photovoltaic group string anti-current detection loop are detected and switched through a change-over switch. The photovoltaic power generation equipment fault arc detection device can rapidly and conveniently detect a photovoltaic string which may have a DC fault arc, and improves the safety performance of the photovoltaic power generation equipment.

Description

TECHNICAL FIELD

[0001] The utility model relates to a kind of detection devices for photovoltaic, more particularly to a kind of detection device of series fault arc in photovoltaic group string in photovoltaic power generation equipment. BACKGROUND

[0002] With the rapid development of photovoltaic industry, the installed capacity of photovoltaic power generation equipment is getting larger and larger, and a considerable number of photovoltaic power generation equipment has been running for more than ten years. Many power generation equipment has problems such as operation and maintenance management not in place, line and component aging, etc. Light may induce safety hazards, and heavy may cause fire accidents. Although fire accidents of photovoltaic power generation equipment are not common, but once it happens, it will bring immeasurable loss to people's life and property, especially the distributed photovoltaic power generation equipment installed in personnel and property intensive user side, which is more harmful in case of fire accident, and people have to pay close attention to it.

[0003] Analyzing the cause of fire of photovoltaic power generation equipment, direct current arc is an important factor to cause fire. Photovoltaic power generation equipment is generally composed of a certain number of photovoltaic strings, and photovoltaic string is composed of a number of photovoltaic components connected in series through lead-out wire. Therefore, the number of connection points of each photovoltaic string is large, and the connection between lead-out wire of photovoltaic component and its junction box may cause direct current series fault arc due to loose joint. How to find the safety hazard of direct current arc in a large number of connection parts is a problem to be solved. UTILITY MODEL CONTENT

[0004] In view of the above-mentioned deficiencies existing in the prior art, the technical problem to be solved by the utility model is to provide a photovoltaic power generation equipment fault arc detection device, which can quickly and conveniently detect the photovoltaic string that may appear series fault arc, and improve the safety performance of photovoltaic power generation equipment.

[0005] In order to solve the above technical problem, the utility model provides a photovoltaic power generation equipment fault arc detection device, which comprises a current detection instrument, the current detection instrument is connected in series with a detection current generator and a current regulator, the two ends of the current detection instrument, the detection current generator and the current regulator connected in series are connected to the corresponding output ends of the photovoltaic string to be detected to form a photovoltaic string anti-current detection loop, and the detection current generator comprises a direct current power supply, and a constant current and constant voltage module connected with the direct current power supply is further arranged in the detection current generator.

[0006] After the technical scheme is applied, the detection current adding device, the current regulator and the current detection instrument connected in series constitute a basic detection device, and the two ends of the detection device are connected to the corresponding output ends of the photovoltaic string to be detected, so that the photovoltaic string, the detection current adding device, the current regulator and the current detection instrument form a loop. The DC power supply in the detection current adding device can load appropriate and stable detection current on the photovoltaic string through the configured constant-current constant-voltage module. The current value is greater than the maximum current generated by the photovoltaic string in the normal working state. The detection current value can be adjusted by the current regulator according to the performance parameters of the photovoltaic string to be detected and the detection requirements. The current value loaded is displayed by the current detection instrument. The detection current greater than the maximum working current value of the photovoltaic string flows through the entire photovoltaic string. If the contact of each connection point of the photovoltaic string is good and there is no part that may cause a DC fault arc, the current detection instrument will display a stable current value. If there are problems such as aging of lines and components and poor contact of each connection point in the photovoltaic string, under the action of the large current loaded, an arc phenomenon will inevitably occur. In the process of generating a DC arc, the current in the detection loop will fluctuate, and the value displayed by the current detection instrument will no longer be stable but fluctuate. If the DC arc generated melts the connection part, the detection loop will be disconnected, and the value displayed by the current detection instrument will be zero. In this way, as long as the value displayed by the current detection instrument fluctuates, it can be judged that the photovoltaic string has a safety hazard that may cause a DC fault arc. Therefore, the photovoltaic string that may cause a fault arc can be detected quickly and conveniently. By detecting all photovoltaic strings in the photovoltaic power generation equipment one by one, the photovoltaic string that has a safety hazard that may cause a fault arc is stopped from running and is further checked and maintained until it can pass the test of the detection device. Therefore, the safety performance of the photovoltaic power generation equipment can be greatly improved.

[0007] In an embodiment of the utility model, the two ends of the current detection instrument and the current regulator connected in series are connected to the corresponding output ends of the photovoltaic string to be detected, respectively, to form a photovoltaic string short-circuit current detection loop. The photovoltaic string short-circuit current detection loop and the photovoltaic string anti-current detection loop are switched by a changeover switch. In this embodiment, the current detection instrument and the current regulator form a loop with the photovoltaic string to be detected. The current detection instrument can detect the current value generated by the photovoltaic string under sunlight, so as to determine whether the photovoltaic string is in a normal working state. If the value displayed by the current detection instrument is zero, the photovoltaic string is in an open circuit state and needs to be repaired before anti-current detection. This avoids interference in the determination of whether the photovoltaic string has a fault arc.

[0008] In another embodiment of the utility model, the DC power supply is a low-voltage and high-current DC power supply. In this embodiment, appropriate current value that may cause a fault arc can be applied to the photovoltaic component to be detected, so as to ensure the realization of DC fault arc detection.

[0009] In another preferred embodiment of the utility model, the direct current power supply is a battery pack. In this embodiment, the battery pack is used as the direct current power supply, which is convenient to carry and facilitates the on-site detection work.

[0010] In a further preferred embodiment of the utility model, the current detection instrument is a direct current ammeter. In this embodiment, the direct current ammeter is used as the current detection instrument, which can meet the detection requirements.

[0011] In another further preferred embodiment of the utility model, the current regulator is a variable resistor. In this embodiment, the current regulation is convenient.

[0012] In another further preferred embodiment of the utility model, the change-over switch is a single-pole change-over switch with a circuit breaking gear. In this embodiment, the connection between the detection device and the photovoltaic string to be detected can be realized by using the circuit breaking gear of the change-over switch, which is safe and reliable.

[0013] In a further preferred embodiment of the utility model, the constant current and constant voltage module is an adjustable constant current and constant voltage module. In this embodiment, the output parameters of the constant current and constant voltage module can be adjusted, the maximum current and voltage that can be applied to the photovoltaic string to be detected can be determined according to the condition of the photovoltaic string in the power station, and the device is more convenient to use. BRIEF DESCRIPTION OF DRAWINGS

[0014] The photovoltaic power generation equipment fault arc detection device of the utility model will be further described in detail below in combination with the drawings and specific embodiments.

[0015] Figure 1 is a structural principle schematic diagram of a specific embodiment of the photovoltaic power generation equipment fault arc detection device of the utility model; DETAILED DESCRIPTION

[0016] In Figure 1The current detector and the current regulator are connected in series, and one end of the series connection is connected to the contact of the first position of the switch and the one end of the detection current generator, the other end of the detection current generator is connected to the contact of the second position of the switch, and the other end of the switch and the other end of the series connection of the current detector and the current regulator form two detection connection ends of the detection device. The detection current generator comprises a DC power supply, and a constant current and constant voltage module connected to the DC power supply is arranged in the detection current generator. When detecting the photovoltaic string in the photovoltaic power generation device, the two detection connection ends are connected to the two output ends of the photovoltaic string to be detected, respectively. Through the switching between the two positions of the switch, two detection circuits are formed. One is a photovoltaic string short-circuit current detection circuit formed by connecting the series connection of the current detector and the current regulator to the photovoltaic string to be detected through the switch. At this time, the current detector can detect the current generated by the photovoltaic string under sunlight, so as to determine whether the photovoltaic string is in a normal working state. The other is a photovoltaic string anti-current detection circuit formed by connecting the series connection of the current detector, the detection current generator and the current regulator to the photovoltaic string to be detected through the switch switched to the second position. At this time, the detection current generator loads a detection current greater than the maximum working current of the photovoltaic string in the circuit through the DC power supply and the constant current and constant voltage module connected thereto. The output current of the detection current generator can be set to be greater than 1.5 times of the maximum working current of the photovoltaic string to be detected through the constant current and constant voltage module, and the actual detection current value can be 1.1-1.5 times of the maximum working current of the photovoltaic string. During the detection process, the current regulator gradually increases, and whether the value of the current detector changes stably is checked. If the value of the current detector fluctuates up and down, it is determined that the photovoltaic string has a safety hazard of causing a DC fault arc.

[0017] As a preferred embodiment, the DC power supply in the detection current generator is a low-voltage and large-current DC power supply, which can be a battery pack convenient to carry, or a DC power supply converted from AC power through a rectifier device. The constant current and constant voltage module can be a commercially available component with appropriate parameters, or a self-made component, and is preferably an adjustable constant current and constant voltage module, which can adjust the maximum output current and appropriate output voltage according to the maximum working current of the photovoltaic string in the photovoltaic power generation device. The current detector is a DC ammeter, and can also be other detection instruments that can detect the value of DC current. The current regulator can be a variable resistor, and the switch is a single-pole switch with a circuit breaking position, so as to facilitate the wiring operation during the detection process.

[0018] The above only lists some preferred embodiments of the present application, but the present application is not limited thereto, and many improvements and changes can be made. As long as the improvements and changes are made on the basis of the basic principles of the present application, they should be considered to fall within the protection scope of the present application.

Claims

1. A photovoltaic power plant fault arc detection apparatus comprising a current detection meter, characterized in that: The current detection instrument is connected in series with a detection current adder and a current regulator, and the two ends of the current detection instrument, the detection current adder and the current regulator connected in series are connected to corresponding output ends of a photovoltaic string to be detected to form a photovoltaic string anti-current detection loop.

2. The photovoltaic power plant fault arc detection apparatus of claim 1, wherein: The two ends of the current detection instrument connected in series with the current regulator are connected to corresponding output ends of a photovoltaic string to be detected to form a photovoltaic string short-circuit current detection loop, and the photovoltaic string short-circuit current detection loop and the photovoltaic string anti-current detection loop are switched by a change-over switch.

3. The photovoltaic power plant fault arc detection apparatus of claim 1, wherein: The direct-current power supply is a low-voltage and large-current direct-current power supply.

4. The photovoltaic power plant fault arc detection apparatus according to claim 1 or 3, characterized in that: The direct-current power supply is a battery pack.

5. The photovoltaic power plant fault arc detection apparatus of claim 1, wherein: The current detection instrument is a direct-current ammeter.

6. The photovoltaic power plant fault arc detection apparatus of claim 1, wherein: The current regulator is a variable resistor.

7. The photovoltaic power plant fault arc detection apparatus of claim 2, wherein: The change-over switch is a single-pole change-over switch with a circuit breaking gear.

8. The photovoltaic power plant fault arc detection apparatus of claim 1, wherein: The constant-current and constant-voltage module is an adjustable constant-current and constant-voltage module.

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