Low-frequency remote cutting intelligent device for special transformer area and low-frequency load cutting method

Abstract

The application discloses a low-frequency remote cutting intelligent device and a low-frequency load cutting method for a special transformer area, and relates to the technical field of power supply, in particular to a low-frequency remote cutting intelligent device for a special transformer area, which comprises a collecting component, an MCU, an executing component and a communication component. The collecting component is used for collecting signals of voltage, current and frequency, and the output end of the collecting component is connected with the MCU. The MCU is used for executing low-frequency load cutting logic according to the signals collected by the collecting component and outputting action instructions. The executing component is connected with the MCU and an intelligent circuit breaker, and is used for controlling the intelligent circuit breaker to execute the action instructions outputted by the MCU. The input end of the communication component is connected with a power distribution master station, the output end of the communication component is connected with the MCU, and the communication component is used for uplink communication of the low-frequency remote cutting intelligent device. The application can realize low-frequency remote cutting of a low-voltage special transformer area and realize more refined low-frequency load cutting function.

Description

Technical Field

[0001] This invention relates to a low-frequency remote load shedding intelligent device and a low-frequency load shedding method for dedicated transformer substations, belonging to the field of power grid frequency stabilization technology. Background Technology

[0002] When a power system experiences an active power deficit, the low-frequency load shedding device sends an activation signal to the circuit breaker, causing it to disconnect a certain amount of load. This ensures that the system frequency does not fall below the allowable value, and the active power is balanced again, preventing the accident from escalating further. Currently, the smallest control unit for low-frequency load shedding is a single 10kV outgoing line from a substation. When a power system experiences an active power deficit and needs to disconnect loads, this would result in the disconnection of the entire 10kV line, including residential loads. To reduce the impact on residential loads, low-frequency load shedding devices need to be installed on the low-voltage side in non-residential load distribution areas radiated by the 10kV line. This allows for the priority disconnection of non-residential loads, with the entire line only disconnected if the frequency requirement cannot be met, thus ensuring power supply to residential areas. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a low-frequency remote shedding intelligent device and method for dedicated transformer substations, enabling low-frequency remote shedding in low-voltage dedicated transformer substations and achieving more refined low-frequency load reduction functions. To achieve the above objective, this invention employs the following technical solution: In a first aspect, the present invention provides a low-frequency remote-cutting intelligent device for a dedicated transformer area, which is connected to an intelligent circuit breaker and a power distribution master station, and includes: a data acquisition component, an MCU, an execution component and a communication component; The acquisition component is used to acquire voltage, current, and frequency signals, and the output terminal of the acquisition component is connected to the MCU. The MCU is used to execute low-frequency load switching logic based on the signals collected by the acquisition component and output action commands. The execution component connects the MCU and the smart circuit breaker and is used to control the smart circuit breaker to execute the action commands output by the MCU; The input end of the communication component is connected to the power distribution master station, and the output end is connected to the MCU, which is used for uplink communication of low-frequency remote-cutting intelligent devices.

[0004] In conjunction with the first aspect, the low-frequency load switching logic further includes: Read the signals collected by the acquisition component and determine whether the protection interlocking conditions are met: If any of the protection interlocking conditions are met, no action command will be output. If all protection interlocking conditions are not met, continue to determine whether the protection action conditions are met. When the protection action conditions are met, it is determined whether the preset action delay time has been reached. If it has, an action command is output and the protection action conditions are recorded; otherwise, the timer continues until the preset action delay time is reached, at which point an action command is output and the protection action conditions are recorded. When the protection action conditions are not met, the protection timer is reset and no action command is output.

[0005] In conjunction with the first aspect, the protective locking conditions further include: Condition 1: The voltage of any phase is zero; Condition 2: The positive sequence voltage is lower than the blocking value; Condition 3: The negative sequence voltage is greater than 5V; Condition 4: The phase current is less than the set value; Condition 5: The frequency is lower than 45Hz; Condition 6: The frequency slip is greater than the blocking value.

[0006] In conjunction with the first aspect, the acquisition component further includes: Metering chip: Used to collect voltage and current signals and calculate effective values, power, and energy parameters; Frequency conversion unit: used to convert three-phase voltage signals into square wave signals after amplification and comparison circuitry, so that the MCU can easily acquire frequencies; Analog signal processing unit: converts voltage and current signals into small voltage signals that can be acquired by the metering chip.

[0007] In conjunction with the first aspect, the execution component further includes: DO circuit: Used to output action commands via switching signals to realize the tripping of the intelligent circuit breaker; DI circuit: used to collect the opening and closing status of the intelligent circuit breaker; RS485 interface: used to transmit action commands to the smart circuit breaker via the downlink direction, and to transmit the opening and closing status of the smart circuit breaker to the MCU via a switch signal.

[0008] In conjunction with the first aspect, the communication component further includes: BLE commissioning unit: Connects to the power distribution master station via Bluetooth to enable wireless commissioning of low-frequency remote-cutting intelligent devices; 4G CAT1 Unit: Connects to the power distribution master station via 4G network to realize uplink communication of low-frequency remote-cutting intelligent devices.

[0009] In conjunction with the first aspect, it further includes an auxiliary module connected to the MCU, the auxiliary module comprising: Power supply components: used to convert 220V AC power into multiple isolated DC power supplies; Watchdog component: Used to provide alerts for MCU malfunctions and improve the reliability of low-frequency remote-controlled intelligent devices; Crystal oscillator assembly: Used to provide an external oscillation waveform for the MCU; SPI FLASH component: Used for persistent storage of data and parameters.

[0010] In conjunction with the first aspect, it further includes an interaction module, which is connected to the MCU, and the interaction module includes: Buttons and LCD display: used to switch between user interfaces and display information; LED components: used to indicate the operating status of low-frequency remote-cut smart devices.

[0011] Secondly, the present invention provides a low-frequency load shedding method based on the first aspect of a low-frequency remote-cutting intelligent device for a dedicated transformer area, comprising: The acquisition component collects voltage, current, and frequency signals; The MCU executes low-frequency load shedding logic based on the signals acquired by the acquisition components and outputs action commands. The component-based intelligent circuit breaker executes the action commands output by the MCU. Uplink communication for low-frequency remote-cutting intelligent devices is achieved through communication components.

[0012] In conjunction with the second aspect, the steps for executing the low-frequency load shedding logic are further as follows: Read the signals collected by the acquisition component and determine whether the protection interlocking conditions are met: If any of the protection interlocking conditions are met, no action command will be output. If all protection interlocking conditions are not met, continue to determine whether the protection action conditions are met. When the protection action conditions are met, it is determined whether the preset action delay time has been reached. If it has, an action command is output and the protection action conditions are recorded; otherwise, the timer continues until the preset action delay time is reached, at which point an action command is output and the protection action conditions are recorded. When the protection action conditions are not met, the protection timer is reset and no action command is output.

[0013] Compared with the prior art, the beneficial effects achieved by the low-frequency remote-cutting intelligent device and low-frequency load shedding method for dedicated transformer substations provided in this embodiment of the invention include: This invention connects to intelligent circuit breakers and distribution master stations, and includes: a data acquisition component, an MCU, an execution component, and a communication component; the data acquisition component is used to acquire voltage, current, and frequency signals, and the output of the data acquisition component is connected to the MCU; this invention accurately detects the load status of dedicated transformer substations, providing data support for the formulation of low-frequency survival strategies for the power grid; The MCU of this invention is used to execute low-frequency load shedding logic based on the signals collected by the acquisition component and output action commands; the execution component is connected to the MCU and the smart circuit breaker and is used to control the smart circuit breaker to execute the action commands output by the MCU; this invention detects the power grid signal in real time and quickly issues a trip command to cut off the load in the dedicated transformer area when the load shedding conditions are met; The input end of the communication component of this invention is connected to the power distribution master station, and the output end is connected to the MCU, which is used for uplink communication of the low-frequency remote switching intelligent device; this invention can receive the tripping command of the power distribution master station to realize remote load disconnection; The execution components of this invention include: DO circuit, DI circuit and RS485 interface, which control the tripping of the low-voltage intelligent circuit breaker in the special transformer area through both RS485 and hard-wiring methods to realize the load disconnection function. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the structure of a low-frequency remote-cutting intelligent device for a dedicated transformer substation provided in Embodiment 1 of the present invention; Figure 2 This is an application scenario of a low-frequency remote-cutting intelligent device for a dedicated transformer substation, provided in Embodiment 1 of the present invention. Figure 3 This is a low-frequency load shedding logic diagram of a low-frequency remote-cutting intelligent device for a dedicated transformer area provided in Embodiment 1 of the present invention; Figure 4 This is a flowchart of the low-frequency load shedding logic in a low-frequency load shedding method for a dedicated transformer area provided in Embodiment 2 of the present invention. Detailed Implementation

[0015] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and should not be used to limit the scope of protection of the present invention.

[0016] Example 1: This invention provides a low-frequency remote-cutting intelligent device for dedicated transformer substations, such as... Figure 2 As shown, it is installed in the dedicated transformer area, connecting to the intelligent circuit breaker for status acquisition and control, and communicating with the power distribution master station via wireless network and 4G communication.

[0017] A low-frequency remote-cutting intelligent device for dedicated transformer substations includes a data acquisition component, an MCU, an execution component, a communication component, an auxiliary module, and an interaction module.

[0018] The output of the acquisition component is connected to the MCU. The acquisition component is used to acquire voltage, current, and frequency signals. For example... Figure 1As shown, the acquisition components include: a metering chip for acquiring voltage and current signals and calculating effective values, power, and energy parameters; a frequency conversion unit for converting the three-phase voltage signals into square wave signals after amplification and comparison circuitry, facilitating frequency acquisition by the MCU; and an analog signal processing unit for converting the voltage and current signals into small voltage signals that the metering chip can acquire. This embodiment of the invention can accurately detect the load conditions of dedicated transformer substations and monitor grid signals in real time, providing data support for the formulation of low-frequency grid sustainability strategies.

[0019] The MCU is used to execute low-frequency load shedding logic based on signals acquired by the acquisition components and output action commands. For example... Figure 3 , 4 As shown, the low-frequency load shedding logic includes: Read the signals collected by the acquisition component and determine whether the protection interlocking conditions are met: If any of the protection interlocking conditions are met, no action command will be output. If all protection interlocking conditions are not met, continue to determine whether the protection action conditions are met. When the protection action conditions are met, it is determined whether the preset action delay time has been reached. If it has, an action command is output and the protection action conditions are recorded; otherwise, the timer continues until the preset action delay time is reached, at which point an action command is output and the protection action conditions are recorded. When the protection action conditions are not met, the protection timer is reset and no action command is output.

[0020] Specifically, the protection blocking conditions include: Condition 1: the voltage of any phase is zero; Condition 2: the positive sequence voltage is lower than the blocking value; Condition 3: the negative sequence voltage is greater than 5V; Condition 4: the phase current is less than the set value; Condition 5: the frequency is lower than 45Hz; Condition 6: the frequency slip is greater than the blocking value.

[0021] This invention detects grid signals in real time and quickly issues a trip command to disconnect the load in the dedicated transformer area when the load disconnection conditions are met.

[0022] The execution component connects the MCU and the smart circuit breaker, and is used to control the smart circuit breaker to execute the action commands output by the MCU. For example... Figure 1 As shown, the execution components include: a DO circuit: used to output action commands via switch signals to realize the tripping of the intelligent circuit breaker; a DI circuit: used to collect the opening and closing status of the intelligent circuit breaker; and an RS485 interface: used to transmit action commands to the intelligent circuit breaker via the downlink direction and to transmit the opening and closing status of the intelligent circuit breaker to the MCU via switch signals. This embodiment of the invention controls the tripping of the low-voltage intelligent circuit breaker in the dedicated transformer area through both RS485 and hard-wiring methods to achieve the load disconnection function.

[0023] The input of the communication component is connected to the power distribution master station, and the output is connected to the MCU, used for uplink communication of low-frequency remote-cutting intelligent devices. For example... Figure 1 As shown, the communication components include: a BLE debugging unit, which connects to the power distribution master station via Bluetooth to enable wireless debugging of the low-frequency remote-cutting intelligent device; and a 4G CAT1 unit, which connects to the power distribution master station via a 4G network for uplink communication of the low-frequency remote-cutting intelligent device. This embodiment of the invention can receive tripping commands from the power distribution master station to remotely disconnect loads.

[0024] like Figure 1 As shown, the auxiliary module is connected to the MCU and includes: a power supply component for converting 220V AC power into multi-channel isolated DC power; a watchdog component for providing MCU operation abnormality alerts and improving the reliability of low-frequency remote-cut intelligent devices; a crystal oscillator component for providing external oscillation waveforms for the MCU; and an SPI FLASH component for persistent storage of data and parameters.

[0025] like Figure 1 As shown, the interaction module is connected to the MCU and includes: buttons and an LCD display for switching the operation interface and displaying information; and LED components for indicating the operating status of the low-frequency remote-controlled intelligent device.

[0026] Example 2: This invention provides a low-frequency load shedding method for dedicated transformer substations based on the first aspect, comprising: The acquisition component collects voltage, current, and frequency signals; The MCU executes low-frequency load shedding logic based on the signals acquired by the acquisition components and outputs action commands. The component-based intelligent circuit breaker executes the action commands output by the MCU. Uplink communication for low-frequency remote-cutting intelligent devices is achieved through communication components.

[0027] The steps of the low-frequency load shedding logic are as follows: Figure 4 As shown, it includes: Read the signals collected by the acquisition component and determine whether the protection interlocking conditions are met: If any of the protection interlocking conditions are met, no action command will be output. If all protection interlocking conditions are not met, continue to determine whether the protection action conditions are met. When the protection action conditions are met, it is determined whether the preset action delay time has been reached. If it has, an action command is output and the protection action conditions are recorded; otherwise, the timer continues until the preset action delay time is reached, at which point an action command is output and the protection action conditions are recorded. When the protection action conditions are not met, the protection timer is reset and no action command is output.

[0028] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0029] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0030] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0031] These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable apparatus for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0032] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A low-frequency remote-cutting intelligent device for dedicated transformer substations, characterized in that, Connects to smart circuit breakers and power distribution master stations, including: data acquisition components, MCU, execution components, and communication components; The acquisition component is used to acquire voltage, current, and frequency signals, and the output terminal of the acquisition component is connected to the MCU. The MCU is used to execute low-frequency load switching logic based on the signals acquired by the acquisition component and output action commands; wherein, the low-frequency load switching logic includes: Read the signals collected by the acquisition component and determine whether the protection interlocking conditions are met: If any of the protection interlocking conditions are met, no action command will be output. If all protection interlocking conditions are not met, continue to determine whether the protection action conditions are met. When the protection action conditions are met, it is determined whether the preset action delay time has been reached. If it has, an action command is output and the protection action conditions are recorded; otherwise, the timer continues until the preset action delay time is reached, at which point an action command is output and the protection action conditions are recorded. When the protection action conditions are not met, the protection timer is reset and no action command is output. The protection interlocking conditions include: Condition 1: The voltage of any phase is zero; Condition 2: The positive sequence voltage is lower than the blocking value; Condition 3: The negative sequence voltage is greater than 5V; Condition 4: The phase current is less than the set value; Condition 5: The frequency is lower than 45Hz; Condition 6: The frequency slip is greater than the blocking value. The execution component connects the MCU and the smart circuit breaker and is used to control the smart circuit breaker to execute the action commands output by the MCU; The execution component includes: DO circuit: Used to output action commands via switching signals to realize the tripping of the intelligent circuit breaker; DI circuit: used to collect the opening and closing status of the intelligent circuit breaker; RS485 interface: used to transmit action commands to the intelligent circuit breaker via the downlink direction and to transmit the opening and closing status of the intelligent circuit breaker to the MCU via a switch signal; the RS485 interface and hard-wiring methods are used to control the opening of the low-voltage intelligent circuit breaker in the special transformer area to realize the load disconnection function. The input end of the communication component is connected to the power distribution master station, and the output end is connected to the MCU, which is used for uplink communication of low-frequency remote-cutting intelligent devices.

2. The low-frequency remote-cutting intelligent device for dedicated transformer substations according to claim 1, characterized in that, The acquisition component includes: Metering chip: Used to collect voltage and current signals and calculate effective values, power, and energy parameters; Frequency conversion unit: used to convert three-phase voltage signals into square wave signals after amplification and comparison circuitry, so that the MCU can easily acquire frequencies; Analog signal processing unit: converts voltage and current signals into small voltage signals that can be acquired by the metering chip.

3. The low-frequency remote-cutting intelligent device for dedicated transformer substations according to claim 1, characterized in that, The communication component includes: BLE commissioning unit: Connects to the power distribution master station via Bluetooth to enable wireless commissioning of low-frequency remote-cutting intelligent devices; 4G CAT1 unit: Connects to the power distribution master station via 4G network and is used for uplink communication of low-frequency remote-cutting intelligent devices.

4. The low-frequency remote-cutting intelligent device for dedicated transformer substations according to claim 1, characterized in that, It also includes an auxiliary module, which is connected to the MCU, and the auxiliary module includes: Power supply components: used to convert 220V AC power into multiple isolated DC power supplies; Watchdog component: Used to provide alerts for MCU malfunctions and improve the reliability of low-frequency remote-controlled intelligent devices; Crystal oscillator assembly: Used to provide an external oscillation waveform for the MCU; SPI FLASH component: Used for persistent storage of data and parameters.

5. The low-frequency remote-cutting intelligent device for dedicated transformer substations according to claim 1, characterized in that, It also includes an interaction module, which is connected to the MCU, and the interaction module includes: Buttons and LCD display: used to switch between user interfaces and display information; LED components: used to indicate the operating status of low-frequency remote-cut smart devices.

6. A low-frequency load shedding method for a dedicated transformer substation, applied to the low-frequency remote shedding intelligent device for a dedicated transformer substation as described in any one of claims 1-5, characterized in that, include: The acquisition component collects voltage, current, and frequency signals; The MCU executes low-frequency load shedding logic based on the signals acquired by the acquisition components and outputs action commands. The steps for executing the low-frequency load shedding logic are as follows: Read the signals collected by the acquisition component and determine whether the protection interlocking conditions are met: If any of the protection interlocking conditions are met, no action command will be output. If all protection interlocking conditions are not met, continue to determine whether the protection action conditions are met. When the protection action conditions are met, it is determined whether the preset action delay time has been reached. If it has, an action command is output and the protection action conditions are recorded; otherwise, the timer continues until the preset action delay time is reached, at which point an action command is output and the protection action conditions are recorded. When the protection action conditions are not met, the protection timer is reset and no action command is output. The component-based intelligent circuit breaker executes the action commands output by the MCU. Uplink communication for low-frequency remote-cut smart devices is achieved through communication components.

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