A new energy low-voltage grid-connected safety control system

Abstract

The utility model discloses a new energy low pressure grid -connected safety control system, including distributed power supply through grid -connected switch connection to the grid bus, the output of grid -connected controller is connected to grid -connected switch, is used for controlling the closing and opening of grid -connected switch, the grid detection module is used for detecting the grid state data, and its output is connected to grid -connected controller, the control system still includes grid -connected reset signal acquisition module, and the grid -connected reset signal acquisition module is used for gathering the reset request signal of grid operation and maintenance personnel, and its output is connected to grid -connected controller, the grid -connected controller is used to control the closing of grid -connected switch according to the grid state signal of grid detection module detection and the reset request signal of grid -connected reset signal acquisition module acquisition, this utility model's advantage lies in: disconnects grid -connected device and can restore grid -connected under the condition of guaranteeing safety, has improved the security and reliability of distributed power supply access grid.

Description

Technical Field

[0001] This utility model relates to the field of grid-connected control of new energy photovoltaic systems, and in particular to a safety control system for low-voltage grid-connected new energy systems. Background Technology

[0002] With the increasing number and capacity of distributed power sources, and the unique advantages of distributed photovoltaic power generation such as local power generation, local grid connection, local conversion, local use, self-consumption, and grid connection of surplus power, it has shown explosive growth in recent years, which will bring new challenges to the operation safety and stability of the power grid.

[0003] However, distributed power sources such as photovoltaics are not allowed to experience islanding effects after being connected to the grid. If islanding occurs, the grid connection switch of the distributed power source needs to be disconnected. Existing technologies contain many fault effect detection and control devices, such as the boundary switch controller with anti-islanding function described in patent application number 201821971434.6. This controller uses a composite multi-judgment passive detection method to determine information such as grid-side fault tripping, and promptly disconnects the boundary switch through the opening and closing control circuit to prevent photovoltaic grid-connected islanding.

[0004] However, the aforementioned existing technologies only consider automatically disconnecting the distributed generation from the grid after a fault condition is detected, but do not consider restoring grid connection control. Furthermore, since the grid is generally in a fault or power outage state after islanding occurs, and may be under maintenance, the grid reset of the distributed generation cannot be a simple reset; safety must also be considered. In existing technologies, after a distributed generation experiences islanding and is disconnected from the grid, safe and reliable grid connection restoration control is not possible. Utility Model Content

[0005] The purpose of this utility model is to overcome the shortcomings of the existing technology and provide a safety control system for low-voltage grid connection of new energy sources. After detecting grid faults or power outages, the grid connection device can be disconnected in a timely manner and grid connection can be restored under safe conditions, thereby improving the safety and reliability of distributed power sources connected to the grid.

[0006] To achieve the above objectives, the technical solution adopted by this utility model is as follows: a new energy low-voltage grid-connected safety control system, including a grid-connected controller, a grid detection module, a grid-connected switch, a grid bus, and a distributed power source; the distributed power source is connected to the grid bus through the grid-connected switch; the output terminal of the grid-connected controller is connected to the grid-connected switch and is used to control the closing and opening of the grid-connected switch; the grid detection module is used to detect grid status data, and its output terminal is connected to the grid-connected controller.

[0007] The control system also includes a grid-connected reset signal acquisition module, which is used to acquire reset request signals from grid operation and maintenance personnel, and its output is connected to the grid-connected controller; the grid-connected controller is used to control the closing of the grid-connected switch according to the grid status signal detected by the grid detection module and the reset request signal acquired by the grid-connected reset signal acquisition module.

[0008] The power grid detection module includes a voltage detection unit, a current detection unit, and a frequency detection unit, which are used to detect voltage, current, and frequency information in the mains power grid. The output terminals of the voltage detection unit, the current detection unit, and the frequency detection unit are all connected to the grid-connected controller.

[0009] The grid-connected controller is connected to the alarm. After the grid-connected switch is turned off, the grid-connected controller drives the alarm to issue the corresponding alarm information.

[0010] The alarm includes a remote alarm, and the grid-connected controller is connected to the remote alarm via a network to drive the remote alarm to send an alarm message of grid disconnection to the operation and maintenance personnel.

[0011] The grid-connected reset signal acquisition module includes a local acquisition unit and / or a remote acquisition unit;

[0012] The local acquisition unit includes a reset button, which is connected to the grid-connected controller. The operation and maintenance personnel use the reset button to input a reset signal into the grid-connected controller.

[0013] The remote acquisition unit includes an Internet of Things (IoT) module. The grid-connected controller is connected to the mobile terminal or maintenance platform of the operation and maintenance personnel through the IoT module. The operation and maintenance personnel input a reset signal through the mobile terminal or maintenance platform, and the grid-connected controller acquires the reset signal through the IoT module.

[0014] The reset button integrates a fingerprint recognition module, which is connected to the grid-connected controller. The grid-connected controller determines whether the reset signal of the reset button is valid based on the signals from the reset button and the fingerprint recognition module.

[0015] The grid-connected controller is connected to a timer. The grid-connected controller performs an action after a set delay before driving the grid-connected switch to close, based on the grid status signal detected by the grid detection module and the reset request signal collected by the grid-connected reset signal acquisition module.

[0016] The advantages of this invention are: it can promptly disconnect the grid-connected device after detecting a grid fault or power outage and restore grid connection while ensuring safety, thereby improving the safety and reliability of distributed power generation access to the grid. Attached Figure Description

[0017] The following is a brief explanation of the contents of each of the accompanying drawings and the markings in the drawings:

[0018] Figure 1 This is a schematic diagram of the principle of the new energy low-voltage grid-connected safety control system of this utility model. Detailed Implementation

[0019] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings and the description of the preferred embodiments.

[0020] This embodiment addresses the issue in existing technologies where distributed power sources, after being connected to the grid, may experience islanding due to grid faults or power outages. Therefore, it proactively disconnects the distributed power source from the grid to prevent islanding. However, how to control the distributed power source to reconnect after the grid resumes operation is a crucial issue. Grid connection must consider not only the grid's condition but also safety. Directly restoring grid connection without considering safety could lead to a recurrence of islanding and pose safety hazards to maintenance personnel within the grid. Therefore, a safe and reliable control scheme for restoring grid connection is needed.

[0021] like Figure 1 As shown in the figure, this embodiment provides a new energy low-voltage grid-connected safety control system, including a grid-connected controller, a grid detection module, a grid-connected switch, a grid bus, and a distributed power source; wherein the distributed power source is connected to the grid bus through the grid-connected switch; the output terminal of the grid-connected controller is connected to the grid-connected switch and is used to control the closing and opening of the grid-connected switch; the grid detection module is used to detect grid status data, and its output terminal is connected to the grid-connected controller; the grid detection module can detect whether the current grid is normal. If a power outage or fault is detected, the grid-connected controller can drive the grid-connected switch to open, and the connection between the distributed power source and the grid bus can be disconnected after the grid-connected switch is opened, thereby avoiding the occurrence of islanding.

[0022] In this embodiment, a grid-connected reset signal acquisition module is provided. The grid-connected reset signal acquisition module is used to acquire reset request signals from grid operation and maintenance personnel, and its output terminal is connected to the grid-connected controller. The grid-connected controller is used to control the closing of the grid-connected switch according to the grid status signal detected by the grid detection module and the reset request signal acquired by the grid-connected reset signal acquisition module.

[0023] To avoid islanding, the distributed power source's grid connection is disconnected. However, restoring grid connection based solely on grid status can compromise grid reliability and the safety of maintenance personnel. Therefore, two conditions must be met for grid restoration: first, the grid must be back to normal; second, a request signal from maintenance personnel must be received. Both are indispensable. A grid detection module can detect whether the grid has returned to normal, and a grid reset signal acquisition module can collect the grid connection request signal from maintenance personnel. Upon detecting both signals, the grid controller drives the grid connection switch to close, restoring the distributed power source's grid connection. To further enhance safety, a timer is included. The grid controller is connected to the timer, and before closing the grid connection switch based on the grid status signal detected by the grid detection module and the reset request signal collected by the grid reset signal acquisition module, the grid controller performs the action after a set delay. When the grid-connected controller determines that grid connection is required based on the grid status and reset request signal, it first delays for a set time before controlling the grid-connected switch to close, thus completing the grid connection operation. This is done to further reserve safety time and avoid safety hazards caused by executing grid connection too quickly. When grid connection is needed, it is executed after a delay of several minutes.

[0024] In this embodiment, the power grid detection module includes a voltage detection unit, a current detection unit, and a frequency detection unit, used to detect voltage, current, and frequency information in the mains power grid. The output terminals of the voltage detection unit, current detection unit, and frequency detection unit are all connected to the grid-connected controller. The grid-connected controller determines whether the current power grid is faulty, has experienced a power outage, or has restored normal power supply based on the detected voltage, current, and frequency information in the power grid.

[0025] In a preferred embodiment of this application, the grid-connected controller is connected to an alarm. After the grid-connected switch is disconnected, the grid-connected controller drives the alarm to issue a corresponding alarm message. The grid connection and disconnection of distributed power sources require notification to the corresponding maintenance personnel. Disconnection indicates a detected grid fault, thus notifying maintenance personnel facilitates rapid subsequent repairs. The primary alarm response is to maintenance personnel.

[0026] Furthermore, the alarm system in this embodiment includes a local alarm system and a remote alarm system. The local alarm system includes a buzzer and other similar devices, and is installed locally for alarm activation. The remote alarm system is used to send alarms to remote backend monitoring or maintenance personnel. The grid-connected controller connects to the remote alarm system via a network to drive the remote alarm system to send a grid disconnection alarm message to the maintenance personnel. The remote alarm system can use a display screen, indicator lights, or other similar devices as carriers of alarm signals.

[0027] In a preferred embodiment of this application, the grid-connected reset signal acquisition module includes a local acquisition unit and / or a remote acquisition unit; wherein the local acquisition unit includes a reset button, which is connected to the grid-connected controller and is used by maintenance personnel to input a reset signal into the grid-connected controller via the reset button;

[0028] The remote acquisition unit includes an IoT module. The grid-connected controller is connected to the mobile terminal or maintenance platform of the maintenance personnel via the IoT module. The maintenance personnel input a reset signal through the mobile terminal or maintenance platform, and the grid-connected controller acquires the reset signal through the IoT module. When grid connection is required after the power grid returns to normal, the maintenance personnel can input a reset request signal on-site via a reset button or remotely via a mobile terminal such as a mobile phone or the maintenance platform. After detecting that the power grid has returned to normal and receiving the reset request signal, the grid-connected controller controls the grid connection switch to close, completing the grid connection and thus achieving safe and reliable grid connection restoration after disconnection.

[0029] In this embodiment, a fingerprint recognition module is integrated into the reset button. The fingerprint recognition module is connected to the grid-connected controller, which determines the validity of the reset signal based on the signals from the reset button and the fingerprint recognition module. The fingerprint recognition module identifies specific fingerprints and outputs corresponding signals based on the recognition results. The grid-connected controller only executes its local reset request signal after receiving a successful fingerprint recognition and the button being pressed; otherwise, it ignores the local button entry request signal. This prevents incorrect grid connection caused by unauthorized personnel triggering the button. The fingerprint recognition module can be pre-registered with the fingerprints of maintenance personnel, thus allowing only these personnel to operate the device.

[0030] This solution restores grid connection under two conditions, improving the safety and reliability of restoring grid connection after disconnection, and enhancing the reliability and safety of distributed power generation in the face of islanding phenomena.

[0031] Obviously, the specific implementation of this invention is not limited to the above-described methods. Any non-substantial improvements made using the inventive concept and technical solution of this invention are within the protection scope of this invention.

Claims

1. A safety control system for low-voltage grid connection of new energy sources, comprising a grid controller, a grid detection module, a grid switch, a grid bus, and a distributed power source; the distributed power source is connected to the grid bus via the grid switch; the output terminal of the grid controller is connected to the grid switch for controlling the closing and opening of the grid switch; the grid detection module is used to detect grid status data, and its output terminal is connected to the grid controller; Its features are: The control system also includes a grid-connected reset signal acquisition module, which is used to acquire reset request signals from grid operation and maintenance personnel, and its output is connected to the grid-connected controller. The grid-connected controller is used to control the closing of the grid-connected switch based on the grid status signal detected by the grid detection module and the reset request signal collected by the grid-connected reset signal acquisition module.

2. The new energy low-voltage grid-connected safety control system as described in claim 1, characterized in that: The power grid detection module includes a voltage detection unit, a current detection unit, and a frequency detection unit, which are used to detect voltage, current, and frequency information in the mains power grid. The output terminals of the voltage detection unit, the current detection unit, and the frequency detection unit are all connected to the grid-connected controller.

3. The new energy low-voltage grid-connected safety control system as described in claim 1, characterized in that: The grid-connected controller is connected to the alarm. After the grid-connected switch is turned off, the grid-connected controller drives the alarm to issue the corresponding alarm information.

4. The new energy low-voltage grid-connected safety control system as described in claim 3, characterized in that: The alarm includes a remote alarm, and the grid-connected controller is connected to the remote alarm via a network to drive the remote alarm to send an alarm message of grid disconnection to the operation and maintenance personnel.

5. A new energy low-voltage grid-connected safety control system as described in any one of claims 1-4, characterized in that: The grid-connected reset signal acquisition module includes a local acquisition unit and / or a remote acquisition unit; The local acquisition unit includes a reset button, which is connected to the grid-connected controller. The operation and maintenance personnel use the reset button to input a reset signal into the grid-connected controller. The remote acquisition unit includes an Internet of Things (IoT) module. The grid-connected controller is connected to the mobile terminal or maintenance platform of the operation and maintenance personnel through the IoT module. The operation and maintenance personnel input a reset signal through the mobile terminal or maintenance platform, and the grid-connected controller acquires the reset signal through the IoT module.

6. The new energy low-voltage grid-connected safety control system as described in claim 5, characterized in that: The reset button integrates a fingerprint recognition module, which is connected to the grid-connected controller. The grid-connected controller determines whether the reset signal of the reset button is valid based on the signals from the reset button and the fingerprint recognition module.

7. A new energy low-voltage grid-connected safety control system as described in any one of claims 1-4, characterized in that: The grid-connected controller is connected to a timer. The grid-connected controller performs an action after a set delay before driving the grid-connected switch to close, based on the grid status signal detected by the grid detection module and the reset request signal collected by the grid-connected reset signal acquisition module.

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