CN205005020U - Photovoltaic power plant leakage detection device - Google Patents

Abstract

A photovoltaic power plant leakage detection device, including a signal generator, a signal receiver, a signal collector and a liquid crystal display, after the signal collector collects relevant data of the photovoltaic system, the signal generator performs signal amplification and processing on the relevant data After filtering, the signal frequency is output. The signal receiver receives the information from the signal generator and sends it to the liquid crystal display for display. When it shows that the insulation value of the positive and negative busbars has dropped, a signal message is sent to warn of positive or negative leakage. The photovoltaic power station leakage detection device of the utility model eliminates the influence of the leakage current by taking different magnifications according to the signal amplification and filtering in the signal generator according to the detected signal size, so as to improve the sensitivity and accuracy of the detection device and ensure grounding The accuracy of fault judgment reduces the false alarm rate.

Description

Photovoltaic power station leakage detection device

technical field

The utility model relates to the field of electrical fault detection devices, in particular to a photovoltaic power station leakage detection device.

Background technique

The DC system of power plants and substations is relatively complex, it needs to supply power, emergency lighting, control, signal, relay protection and automatic devices, AC uninterruptible power supply, etc., which play an extremely important role in the reliable operation of power plants and substations . One-point grounding occurs in the DC system. If the search is not timely, the second point grounding may occur. After a two-point grounding fault occurs in the DC system, a grounding short circuit can be formed, causing relay protection, signal, and automatic devices to malfunction or refuse to operate, or causing DC fuses to blow, causing protection, automatic devices, and control circuits to lose power, directly threatening a The safety of the equipment, so the power system has high requirements on the reliability of the DC system. The DC system is an operating system in which the battery and the floating charging device are connected in parallel to supply DC loads. Under normal circumstances, the positive and negative busbars of the DC power supply are insulated from the ground. When a point of the circuit is grounded, it does not affect the operation of the DC system under normal circumstances. However, when two or more points of the circuit are grounded, it will cause a short circuit between the positive and negative poles, and the switch and protection will malfunction or refuse to operate. Grounding faults often occur. For equipment with poor operating environment and long running time, there are more chances of failures, and there are often several grounding points at the same time, which is very difficult to find. Therefore, it is necessary to accurately detect the ground fault when it occurs, so as to realize the rapid protection of the fault.

At present, most leakage detection devices are not sensitive enough, and are easily interfered by other factors, so the accuracy is limited.

Utility model content

Based on this, the purpose of the utility model is to provide a photovoltaic power station leakage detection device with high detection accuracy.

A photovoltaic power plant leakage detection device, including a signal generator, a signal receiver, a signal collector and a liquid crystal display, the signal collector collects relevant data of the photovoltaic system, and sends it to the signal generator, and the signal generator performs Signal amplification and filtering, and then according to the signal receiver to receive the information sent by the signal generator, and send the information to the LCD display for display, once the grounding level of the system reaches the set tripping level, the output signal alarm , to warn of positive or negative earth leakage.

The signal generator includes an analog-to-digital conversion circuit and a signal amplification and filtering circuit, the signal generator is connected to a controller, and the controller controls the state of the signal generator.

Further, an analog multi-way switch is also included, and each analog switch of the analog multi-way switch is connected with one positive/negative input signal to complete switching of one input signal.

Furthermore, it also includes an alarm unit and a key unit.

The liquid crystal display displays the voltage of the positive and negative busbars of the device, the total voltage and the insulation resistance of the positive and negative poles to the ground. When the voltage of the positive and negative busbars and the insulation resistance do not meet the set value, the controller controls the alarm unit to send an alarm signal.

The keyboard unit communicates with the controller in a wired or wireless manner. If the insulation of the positive and negative busbars of the DC system is detected to be lowered, the alarm unit sends an alarm signal, and the keyboard unit cancels the alarm signal.

The leakage current signal detected by the photovoltaic power station leakage detection device of the utility model is very small, but the positive and negative bus voltage signal values are very large, and the detected signal size is taken according to the signal amplification and filtering circuit in the signal generator. After different magnifications, the influence of leakage current is eliminated to improve the sensitivity and precision of the detection device, ensure the accuracy of ground fault judgment, and reduce the false alarm rate.

Description of drawings

FIG. 1 is an application diagram of a photovoltaic power station leakage detection device in an embodiment of the present invention.

Fig. 2 is a schematic diagram of a photovoltaic power station leakage detection device in an embodiment of the present invention.

FIG. 3 is a schematic diagram of the signal generator in FIG. 2 .

FIG. 4 is a schematic diagram of the signal receiver in FIG. 2 .

detailed description

In order to facilitate the understanding of the utility model, the utility model will be described more fully below with reference to the relevant drawings. Preferred embodiments of the present utility model are provided in the accompanying drawings. However, the invention can be embodied in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present invention more thorough and comprehensive.

It should be noted that when an element is referred to as being “fixed on” another element, it may be directly on the other element or there may be an intervening element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or intervening elements may also be present. The terms "vertical," "horizontal," "left," "right," and similar expressions are used herein for purposes of illustration only.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the technical field of this invention. The terminology used in the description of the utility model herein is only for the purpose of describing specific embodiments, and is not intended to limit the utility model. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

Please refer to Figure 1, which is an application diagram of a photovoltaic power plant leakage detection device in an embodiment of the present invention. The positive and negative ends of the photovoltaic module 1 pass through the first fuse 2 and the second fuse 3 and the inverter 4 After connecting, the signal is sent out through the third fuse 5, and the leakage detection device 6 of the photovoltaic power station is placed between the first fuse 2 and the second fuse 3 of the photovoltaic module, and is connected to the positive/negative pole through the fuse 7. The leakage detection device 6 of the photovoltaic power station will directly detect the leakage current of the positive and negative busbars, and once the grounding level of the system reaches the set trip level, a signal will be sent to warn the positive or negative leakage.

Please refer to FIG. 2 , which is a schematic diagram of a photovoltaic power plant leakage detection device of the present invention, including a signal generator 12 , a signal receiver 13 , a signal collector 11 and a liquid crystal display 14 .

The signal generator 12 includes an analog-to-digital conversion circuit 121 and a signal amplification and filtering circuit 122 . The analog-to-digital conversion circuit 121 is used to convert the analog signal collected by the signal collector 11 into a digital signal.

Further, it also includes an analog multi-way switch 111, and each analog switch of the analog multi-way switch 111 is connected with one positive/negative input signal to complete the switching of one input signal. In a specific embodiment, when the positive leakage , the analog switch connected to the positive pole will be closed, and the other analog switches will be in the disconnected state, and the input signal of the gate will be output to the output terminal of the analog multi-way switch 111; when the negative pole is leaking, the analog switch connected to the negative pole will be When the switch is closed, other analog switches will be in the disconnected state, and the input signal of the selected path is output to the output terminal of the analog multi-way switch 111

Further, the signal generator 12 is connected with a controller 16 , and the controller 16 controls the state of the signal generator 12 .

Furthermore, the controller 16 is connected with an alarm unit 17 and a button unit 18 .

The keyboard unit 18 communicates with the controller 14 through a display interface in a wired or wireless manner, and the liquid crystal display 14 displays the voltage of the positive and negative busbars of the device, the total voltage and the insulation resistance of the positive and negative poles to the ground. When the bus voltage and insulation resistance do not meet the set value, the controller 14 controls the alarm unit 17 to send out an alarm signal, and the keyboard unit 18 cancels the alarm signal when the administrator knows about it.

Please refer to Fig. 3, it is the schematic diagram of the signal generator 12 of the utility model embodiment, the analog signal of signal collection is converted into digital signal by described analog-to-digital conversion circuit 121, sends to described signal after the signal is analyzed The data information is displayed on the liquid crystal display 14, and then the data information is fed back to the controller 16, and then the controller 16 controls the operation mode of the device.

Please refer to Fig. 4, it is the schematic diagram of the signal receiver of the utility model embodiment, the signal that the signal collects carries out signal amplification and filtering through the described signal amplification filter circuit 122, and the analog signal is converted by the described analog-to-digital conversion circuit 121 It is a digital signal, which is sent to the liquid crystal display 14 to display data information after signal processing and fault analysis.

The leakage current signal detected by the photovoltaic power station leakage detection device of the utility model is very small, but the positive and negative bus voltage signal values are large, according to the signal amplification filter circuit and power amplification circuit in the signal generator, according to the The detected signal size adopts different magnifications to eliminate the influence of leakage current, so as to improve the sensitivity and precision of the detection device, ensure the accuracy of ground fault judgment, and reduce the false alarm rate.

The above-mentioned embodiments only express several implementation modes of the present utility model, and the description thereof is relatively specific and detailed, but it should not be construed as limiting the patent scope of the present utility model. It should be noted that those skilled in the art can make several modifications and improvements without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the scope of protection of the utility model patent should be based on the appended claims.

Claims (6)

1. A photovoltaic power plant leakage detection device, comprising a signal generator, a signal receiver, a signal collector and a liquid crystal display, is characterized in that, after the relevant data of the photovoltaic system is collected by the signal collector, the The relevant data is amplified and filtered to output the signal frequency. The signal receiver receives the information sent by the signal generator and sends it to the liquid crystal display for display. When it shows that the insulation value of the positive and negative busbars has dropped, a signal message is sent. Warns of positive or negative leakage. 2. The photovoltaic power plant leakage detection device according to claim 1, wherein the signal generator includes an analog-to-digital conversion circuit and a signal amplification filter circuit, and the analog-to-digital conversion circuit is used to collect the signal collector The received analog signal is converted into a digital signal. 3. The photovoltaic power plant leakage detection device according to claim 1, further comprising an analog multi-way switch, each analog switch of the analog multi-way switch is connected with one positive/negative input signal to complete one Input signal switching. 4. The photovoltaic power plant leakage detection device according to claim 1, further comprising a controller, the signal generator is connected to the controller, and the controller controls the operating state of the signal generator . 5 . The photovoltaic power plant leakage detection device according to claim 4 , further comprising an alarm unit connected to the controller, and the controller controls the alarm unit to send out an alarm signal. 6. The photovoltaic power plant leakage detection device according to claim 5, further comprising a key unit, the key unit communicates with the controller through the display interface to transmit relevant information, and the key unit controls the The off state of the alarm unit described above.