Photovoltaic box transformer substation with single-phase grounding overvoltage protection

Abstract

The utility model belongs to the technical field of photovoltaic box transformers, and particularly relates to a photovoltaic box transformer with single-phase grounding overvoltage protection, which comprises a single-phase grounding protection module, a zero sequence voltage monitoring module, an AND gate circuit module, a single-phase grounding time limit module and a control device. A voltage high-level signal is output; the AND gate circuit module receives the input operation signal of the single-phase grounding protection module and the voltage high-level signal of the comparison module, and outputs the high-level signal; the single-phase grounding time limit module receives the high-level signal of the AND gate circuit module for time limit processing, and outputs an electric signal to the controller after receiving the high-level signal after the time limit processing is finished; and the controller receives the electric signal of the single-phase grounding time limit module, generates an alarm command and transmits the alarm command to an external server. According to the utility model, the problem of inaccurate protection action of the single-phase grounding overvoltage protection measure of the photovoltaic box transformer substation in the prior art can be solved.

Description

TECHNICAL FIELD

[0001] The utility model belongs to photovoltaic box transformer technical field especially relates to photovoltaic box transformer with single -phase grounding overvoltage protection. BACKGROUND

[0002] With the wide application of photovoltaic energy, photovoltaic box transformer as an important equipment in photovoltaic power generation system, its stability and reliability of operation are crucial, however, photovoltaic box transformer is usually installed in outdoor environment, especially in high altitude area, faces the severe operating condition, on the one hand, the air pressure of high altitude area is low, and the air is rarefied, makes the heat dissipation of photovoltaic box transformer increase, is easy to cause equipment operating temperature to rise, influences the normal operation and service life of equipment, on the other hand, photovoltaic box transformer system circuit often adopts the mode of neutral point not grounding, this mode although has the advantages such as reducing the damage to electrical equipment, guaranteeing the continuity of power supply to some extent, but when single -phase grounding fault occurs, it is easy to cause rigid single -phase to ground short circuit and gap arc light short circuit and other problems, and the safe operation of power grid is threatened.

[0003] The single -phase grounding overvoltage protection measure adopted in the prior art can protect overvoltage to some extent, but in actual application, there are problems such as inaccurate protection action and easy misoperation, which increases the operation and maintenance cost and affects the normal operation and economic benefit of photovoltaic power station. Therefore, how to effectively solve the heat dissipation problem of photovoltaic box transformer in high altitude area and improve the accuracy and reliability of single -phase grounding overvoltage protection has become a problem to be solved in the current photovoltaic box transformer technical field. UTILITY MODEL CONTENTS

[0004] The utility model solves the technical problem to provide a kind of photovoltaic box transformer with single -phase grounding overvoltage protection, to solve the problem of inaccurate protection action of single -phase grounding overvoltage protection measure of photovoltaic box transformer in prior art.

[0005] The utility model provides basic scheme: photovoltaic box transformer with single -phase grounding overvoltage protection, including single -phase grounding protection module, zero sequence voltage monitoring module, and gate circuit module, single -phase grounding time limit module and control device, the control device includes controller and comparison module, the input of zero sequence voltage monitoring module and comparison module is connected, the output of comparison module and single -phase grounding protection module are all connected with the input of and gate circuit module, the output of and gate circuit is connected with the input of single -phase grounding time limit module, the single -phase grounding time limit module is also connected with controller electrically;

[0006] The comparison module is used for receiving the monitoring signal of the zero sequence voltage monitoring module and outputting a voltage low level signal or a voltage high level signal; the AND gate circuit module receives the operation signal of the single-phase grounding protection module and the voltage high level signal of the comparison module and outputs a high level signal; the single-phase grounding time limit module receives the high level signal of the AND gate circuit module for time limit processing and outputs an electric signal to the controller after receiving the high level signal after the time limit processing ends; the controller receives the electric signal of the single-phase grounding time limit module and generates an alarm command to be transmitted to an external server.

[0007] Further, the single-phase grounding protection module adopts an overvoltage protector, which is also electrically connected with the controller, and the controller is used for controlling the operation state and the return operation state of the overvoltage protector.

[0008] Further, the comparison module comprises a zero sequence voltage comparator, an input end of the zero sequence voltage comparator is connected with the zero sequence voltage monitoring module, and an output end of the zero sequence voltage comparator is connected with the AND gate circuit module, and the zero sequence voltage comparator is used for outputting a voltage low level signal or a voltage high level signal when receiving the zero sequence voltage signal of the zero sequence voltage monitoring module and reaching saturation.

[0009] Further, the AND gate circuit module is also electrically connected with the controller, the AND gate circuit module outputs a high level signal 1 according to the operation signal of the single-phase grounding protection module and the voltage high level signal of the comparison module received, and the AND gate circuit module outputs a low level signal 0 according to the return operation signal of the single-phase grounding protection module and / or the voltage low level signal of the comparison module received, and the controller is used for receiving the high level signal 1 to control the single-phase grounding time limit module to perform time limit processing.

[0010] Further, the single-phase grounding time limit module adopts a single-phase grounding time limit timer, the single-phase grounding time limit timer is electrically connected with the controller, the controller receives the high level signal 1 to control the single-phase grounding time limit timer to perform time limit processing, and the controller generates an alarm command to be transmitted to an external server when receiving the high level signal 1 after the time limit processing ends.

[0011] Further, the control device further comprises an alarm, the alarm is electrically connected with the controller, and the controller is further used for receiving the high level signal 1 to control the alarm to perform alarm processing after the time limit processing of the single-phase grounding time limit timer ends.

[0012] Further, the alarm comprises one of a buzzer and a warning light.

[0013] The principle and advantages of this utility model are as follows: In this solution, the existing single-phase grounding overvoltage protection measures for photovoltaic transformer substations have the problem of inaccurate protection action. Based on the original single-phase grounding overvoltage protection circuit, an AND gate circuit module is used for the first signal reception. In the first signal reception, the single-phase grounding overvoltage protection circuit components need to be in operation. At the same time, the zero-sequence voltage monitoring module detects that the zero-sequence voltage exceeds the threshold voltage set in the zero-sequence voltage comparator. Only when both states occur will the AND gate circuit module of this application output a high-level signal and transmit it to the controller. Subsequently, the controller controls the single-phase grounding time limit module to perform time limit processing. After the preset time limit, the controller performs a second signal reception. After receiving the high-level signal transmitted by the AND gate circuit module, an alarm action is performed. That is, on the one hand, the alarm command is transmitted to the external server for the user to handle in time, and on the other hand, an alarm signal is issued through the alarm device to remind the user to promptly detect the situation of excessive zero-sequence voltage.

[0014] Therefore, in this application, compared with the single-phase grounding overvoltage protection in the prior art, the secondary voltage signal is used for judgment, which improves the accuracy of the overvoltage protection action. Attached Figure Description

[0015] Figure 1 This is a functional block diagram of an embodiment of the present utility model. Detailed Implementation

[0016] The following detailed description illustrates the specific implementation method:

[0017] Example 1:

[0018] Example 1 is basically as shown in the attached document. Figure 1 As shown: A photovoltaic transformer with single-phase grounding overvoltage protection includes a single-phase grounding protection module, a zero-sequence voltage monitoring module, an AND gate circuit module, a single-phase grounding time limit module, and a control device. The control device includes a controller, a comparison module, and an alarm.

[0019] In this solution, the single-phase grounding protection module, zero-sequence voltage monitoring module, single-phase grounding time-limit module, and alarm are all controlled by a controller. To better demonstrate the technical solution of this application, as... Figure 1 As shown, the connection method between the above modules is as follows:

[0020] The zero-sequence voltage monitoring module is controlled by a controller to control its on / off state. At the same time, the output terminal of the zero-sequence voltage monitoring module is connected to the input terminal of the comparator module, the output terminal of the comparator module is connected to the input terminal of the AND gate module, and the single-phase grounding protection module is also connected to the input terminal of the AND gate module.

[0021] In the above connection, the zero sequence voltage monitoring module monitors the zero sequence voltage of the photovoltaic box transformer by using a voltage transformer. After the controller controls the voltage transformer to start, the monitored zero sequence voltage signal is transmitted to the comparison module. In this application, the comparison module is a zero sequence voltage comparator. The input end of the zero sequence voltage comparator is connected to the zero sequence voltage monitoring module, and the output end is connected to the AND gate circuit module. The core element of the zero sequence voltage comparator is an operational amplifier, which includes two input ends, namely the same phase input end and the opposite phase input end. The zero sequence voltage signal received by the same phase input end is denoted as the positive power voltage, and the zero sequence voltage signal received by the opposite phase input end is denoted as the negative power voltage. At the same time, a threshold voltage is set in the zero sequence voltage comparator. According to the size of the zero sequence voltage signal, when the zero sequence voltage signal is received and reaches saturation, if the zero sequence voltage signal does not exceed the threshold voltage, a low voltage signal is output, and if the zero sequence voltage signal exceeds the threshold voltage, a high voltage signal is output. The principle of the above comparison module is realized by using its circuit structure.

[0022] After the comparison module compares the size of the zero sequence voltage signal, a low voltage signal is output to the AND gate circuit module, and the AND gate circuit module outputs signal 0, indicating a low voltage signal.

[0023] When the comparison module outputs a high voltage signal, the AND gate circuit module meets one condition. In addition, it also needs to receive the operating state of the single-phase grounding protection module. In this application, the single-phase grounding protection module controls its operating state by the controller. The operating state of the single-phase grounding protection module under the control of the controller includes the input operating state (on) and the return operating state (off). When the AND gate circuit module receives that the single-phase grounding protection module is in the return operating state, even if the comparison module outputs a high voltage signal, the AND gate circuit module still outputs signal 0, i.e. a low voltage signal. When the AND gate circuit module receives that the single-phase grounding protection module is in the input operating state and the comparison module outputs a high voltage signal to the AND gate circuit module, the AND gate circuit module outputs signal 1, indicating a high voltage signal. In this embodiment, the single-phase grounding protection module is a single-phase grounding overvoltage protection circuit, and the AND gate circuit module is an AND gate circuit. Therefore, the above scheme is realized by the function of the circuit structure.

[0024] After the AND gate module outputs a high-level signal, the controller controls the single-phase grounding time-limit module to perform time-limit processing. In this scheme, the single-phase grounding time-limit module is a single-phase grounding time-limit timer. The time-limit processing performed by the single-phase grounding time-limit timer is timing processing, for example, 3-minute timing processing. After the 3-minute timing processing ends, if the controller still receives a high-level signal output by the AND gate module, it indicates that the voltage in the photovoltaic box transformer is indeed abnormal, and an alarm action needs to be performed, that is, an alarm command is generated and transmitted to an external server. After the time-limit processing ends, if the controller does not receive a high-level signal, it indicates that the voltage in the photovoltaic box transformer is not abnormal, and no alarm action needs to be performed. However, the controller will transmit the signal to the external server and store it in the server as an abnormal record.

[0025] When the controller performs an alarm action, the alarm is electrically connected to the controller, and the controller also controls the alarm to perform an alarm. In this application, the alarm is a buzzer to alert users to handle it in time.

[0026] In this embodiment, the controller is a single-chip microcomputer, and the single-phase grounding time-limit timer is a built-in timer in the single-chip microcomputer.

[0027] Embodiment Two:

[0028] The difference between Embodiment Two and Embodiment One is that Embodiment Two further includes a temperature detection module. The temperature detection module is installed on the photovoltaic box transformer equipment, and is electrically connected to the controller. The temperature detection module is used to detect a temperature signal of the photovoltaic box transformer equipment. The controller is further used to receive the temperature signal and synchronously transmit the temperature signal to the external server when generating an alarm command and transmitting it to the external server.

[0029] In this scheme, the photovoltaic box transformer circuit may be affected by the temperature of the photovoltaic box transformer equipment when overvoltage occurs. Therefore, when the controller transmits an alarm command to the external server, the temperature signal is also transmitted to the external server, which facilitates users to compare and check the temperature of the photovoltaic box transformer equipment, that is, users do not need to perform temperature detection operations on the photovoltaic box transformer installation site again.

[0030] The above is only an embodiment of the present application, and common knowledge such as specific structures and properties in the scheme is not described in detail, the ordinary skilled person in the art knows all the ordinary technical knowledge in the technical field of the present application before the application date or the priority date, can know all the prior art in the field, and has the ability to apply conventional experimental means before the date, the ordinary skilled person in the art can improve and implement the present scheme under the inspiration given in the present application, and some typical known structures or known methods should not be an obstacle for the ordinary skilled person in the art to implement the present application. It should be pointed out that, for those skilled in the art, without departing from the structure of the present application, a number of modifications and improvements can be made, which should also be considered as the protection scope of the present application, which will not affect the effect and practicality of the present application. The protection scope of the present application should be subject to the content of its claims, and the specific implementation mode and the like in the specification can be used to explain the content of the claims.

Claims

1. A photovoltaic box transformer with single-phase ground overvoltage protection, characterized in that: The single-phase grounding protection module, the zero sequence voltage monitoring module, the AND gate circuit module, the single-phase grounding time limit module and the control device, the control device includes a controller and a comparison module, the input end of the zero sequence voltage monitoring module is connected with the comparison module, the output end of the comparison module and the single-phase grounding protection module are connected with the input end of the AND gate circuit module, the output end of the AND gate circuit is connected with the input end of the single-phase grounding time limit module, and the single-phase grounding time limit module is also connected with the controller. The comparison module is used for receiving the monitoring signal of the zero sequence voltage monitoring module and outputting a voltage low level signal or a voltage high level signal; the AND gate circuit module receives the running signal of the single-phase grounding protection module and the voltage high level signal of the comparison module and outputs a high level signal; the single-phase grounding time limit module receives the high level signal of the AND gate circuit module for time limit processing and outputs an electric signal to the controller after receiving the high level signal after the time limit processing is finished; and the controller receives the electric signal of the single-phase grounding time limit module and generates an alarm command to be transmitted to an external server.

2. The photovoltaic box transformer with single-phase ground overvoltage protection of claim 1, wherein: The single-phase grounding protection module adopts an overvoltage protector, the overvoltage protector is also connected with the controller, and the controller is used for controlling the running state and the return running state of the overvoltage protector.

3. The photovoltaic box transformer with single-phase ground overvoltage protection of claim 2, wherein: The comparison module includes a zero sequence voltage comparator, the input end of the zero sequence voltage comparator is connected with the zero sequence voltage monitoring module, and the output end is connected with the AND gate circuit module; and the zero sequence voltage comparator is used for outputting a voltage low level signal or a voltage high level signal when receiving the zero sequence voltage signal of the zero sequence voltage monitoring module and reaching saturation.

4. The photovoltaic box transformer with single-phase ground overvoltage protection of claim 3, wherein: The AND gate circuit module is also connected with the controller, the AND gate circuit module outputs a high level signal 1 according to the running signal of the single-phase grounding protection module and the voltage high level signal of the comparison module, and the AND gate circuit module outputs a low level signal 0 according to the return running signal of the single-phase grounding protection module and / or the voltage low level signal of the comparison module; and the controller is used for receiving the high level signal 1 to control the single-phase grounding time limit module to perform time limit processing.

5. The photovoltaic box transformer with single-phase ground overvoltage protection of claim 4, wherein: The single-phase grounding time limit module adopts a single-phase grounding time limit timer, the single-phase grounding time limit timer is connected with the controller, the controller receives the high level signal 1 to control the single-phase grounding time limit timer to perform time limit processing, and generates an alarm command to be transmitted to an external server when receiving the high level signal 1 after the time limit processing is finished.

6. The photovoltaic box transformer with single-phase ground overvoltage protection of claim 5, wherein: The control device further includes an alarm, the alarm is connected with the controller, and the controller is further used for receiving the high level signal 1 to control the alarm to perform alarm processing after the time limit processing of the single-phase grounding time limit timer is finished.

7. The photovoltaic box transformer with single-phase ground overvoltage protection of claim 6, wherein: The alarm includes one of a buzzer and a warning light.

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