A Green and Low-Carbon Dual-Channel Power Line Carrier Communication and Service Scheduling Method

Abstract

This invention provides a green and low-carbon dual-channel power line carrier communication and service scheduling method, relating to the field of power line carrier communication technology. The invention achieves high reliability and anti-interference capability of the communication system by constructing a dual-band, dual-loop redundant communication design using first and second carrier loops corresponding to the first and second frequency bands, respectively. Specifically, the first and second carrier loops transmit service data of different priorities in the first and second frequency bands, respectively. By classifying the service data according to its characteristics and allocating it to different carrier loops for transmission, isolated transmission of services is achieved, avoiding service conflicts. Simultaneously, by monitoring link quality parameters in real time and performing switching operations when the quality falls below a threshold, dynamic optimization of the communication link is achieved, thereby adapting to changes in the power line environment, timely avoiding interference, and maintaining stable communication performance.

Description

Technical Field

[0001] This invention relates to the field of power line carrier communication technology, and in particular to a green and low-carbon dual-channel power line carrier communication and service scheduling method, which is applicable to industrial scenarios such as photovoltaic power plants that require high reliability and low latency communication. Background Technology

[0002] As a core carrier of green and low-carbon energy, the large-scale and efficient operation of photovoltaic (PV) power plants has become an industry trend. The communication system between string inverters and transformer substations / centralized terminals is a crucial link in ensuring the green and efficient operation of PV power plants and achieving efficient energy utilization. In existing PV power plants, reliable communication between string inverters and centralized terminals is essential for efficient operation. Traditional solutions often use RS485 wired communication, requiring additional communication cables, which leads to high costs, complex construction and maintenance, and susceptibility to interference. Furthermore, the production and laying of communication cables consume large amounts of metals and plastics, resulting in high carbon emissions. On the other hand, the long-term wear, aging, and replacement of cables further increase energy consumption and environmental pollution, which is inconsistent with the green and low-carbon development goals of PV power plants. Power line carrier (PLC) communication utilizes existing power lines to transmit data, avoiding additional wiring and representing a more advantageous alternative.

[0003] Power line communication (PLC) technology uses power lines as the communication medium, eliminating the need for additional communication lines and finding wide application in industrial automation, energy management, and other fields. In photovoltaic power plants, the communication system needs to simultaneously support large volumes of status monitoring (such as second-level or minute-level equipment status inspection data) and low-latency control commands (such as millisecond-level equipment control commands). Traditional single-channel PLC solutions have the following problems: (1) Poor anti-interference ability; power line noise and load changes can easily lead to communication interruption; (2) It is impossible to distinguish business priorities, and large-volume business can easily block low-latency business; (3) Lack of redundancy mechanism, single point of failure leads to complete communication interruption.

[0004] Although existing technologies include dual-circuit or dual-band solutions, the problems of service priority conflicts and low redundancy reliability have not yet been resolved. Summary of the Invention

[0005] In view of this, the core technical problem to be solved by the present invention is: how to improve the reliability, anti-interference capability and service transmission efficiency of the power line carrier communication system without adding additional communication lines, while meeting the transmission requirements of different priority services, thereby improving the service transmission reliability and real-time performance of the communication system used for power line carrier in complex environments.

[0006] On one hand, this invention provides a green and low-carbon dual-channel power line carrier communication and service scheduling method. This method is applied to a communication system, which includes a communication host and at least one communication slave connected via an AC power line. The communication host has a built-in first host carrier unit and a second host carrier unit, and the communication slave has a built-in first slave carrier unit and a second slave carrier unit. The dual-channel power line carrier communication and service scheduling method includes the following steps: S100, Initialization: Controlling the first host carrier unit and the second host carrier unit of the communication host to operate in a first frequency band and a second frequency band respectively, and controlling the first slave carrier unit and the second slave carrier unit of the communication slave to communicate with the first host. The carrier unit and the second host carrier unit are coupled to form the first carrier loop and the second carrier loop respectively; S200, Service scheduling and transmission: Obtain the service data to be transmitted, which includes first type data with first service characteristics and second type data with second service characteristics; allocate the first type data to the first carrier loop for transmission, and allocate the second type data to the second carrier loop for transmission; S300, Link quality monitoring and switching: Monitor the link quality parameters of the first carrier loop and the second carrier loop in real time; when it is determined that the link quality of either the first carrier loop or the second carrier loop is lower than a preset quality threshold, switch the service data transmitted on the current link to another transmission link for transmission.

[0007] Optionally, in step S200: the first service characteristic is that the data volume is greater than the preset traffic threshold, and the first type of data is device status inspection data at the second or minute level; the second service characteristic is that the transmission delay requirement is lower than the preset delay threshold, and the second type of data is device control instructions at the millisecond level.

[0008] Optionally, step S200 specifically includes: setting the highest transmission priority for the second type of data; and dynamically allocating transmission time slot resources for the second carrier loop based on the highest transmission priority to ensure that the end-to-end transmission delay of the second type of data does not exceed 60ms.

[0009] Optionally, in step S300, the link quality parameters include one or more of signal-to-noise ratio, packet loss rate, and transmission delay; the preset quality threshold includes a signal-to-noise ratio threshold, a packet loss rate threshold, and a transmission delay threshold; when it is determined that the link quality of either the first carrier loop or the second carrier loop is lower than the preset quality threshold, it is specifically determined that the link quality of the loop is lower than the preset quality threshold when the signal-to-noise ratio of a certain carrier loop is detected to be lower than 20dB, the packet loss rate is higher than 1%, or the transmission delay is abnormal.

[0010] Optionally, in step S300, the total time from determining that the link quality is lower than a preset threshold to completing the service data switching does not exceed 50ms.

[0011] Optionally, step S100 specifically includes: coupling the carrier signals generated by the first host carrier unit and the second host carrier unit to the AC power line side with a voltage higher than 800VAC through the built-in isolation coupling circuit.

[0012] Optionally, the following steps are also included: S400, multi-node network scheduling: when there are multiple communication slaves, different transmission time slots are allocated to each communication slave that is simultaneously connected to the first carrier circuit or simultaneously connected to the second carrier circuit; based on the allocated transmission time slots, each communication slave is scheduled to transmit data within its assigned time slot to avoid multi-node data conflicts.

[0013] Optionally, the first carrier circuit and the second carrier circuit are coupled to different phase line combinations of the AC power line.

[0014] Optionally, the AC power lines include phase A, phase B, and phase C lines, and the phase combination includes any two of phase A, phase B, and phase C lines.

[0015] Optionally, the first frequency band and the second frequency band are non-overlapping power line carrier communication frequency bands, and the frequency interval between the two frequency bands is not less than 0.5MHz.

[0016] The implementation of this invention offers the following advantages: By constructing a dual-band, dual-loop redundant communication design with first and second carrier loops corresponding to the first and second frequency bands respectively, this invention achieves high reliability and anti-interference capability of the communication system. Specifically, the first and second carrier loops transmit service data of different priorities in the first and second frequency bands, respectively. By classifying service data according to its characteristics and allocating it to different carrier loops for transmission, isolated transmission of services is achieved, avoiding service conflicts. Simultaneously, by real-time monitoring of link quality parameters and performing switching operations when the quality falls below a threshold, dynamic optimization of the communication link is achieved, enabling it to adapt to changes in the power line environment, promptly avoid interference, and maintain stable communication performance. In summary, this invention, through the synergistic effect of dual-loop redundant communication design, isolated transmission of service points, and dynamic link switching, effectively improves the reliability, service transmission efficiency, and adaptability to complex environments of the power line carrier communication system. While enhancing communication reliability and real-time performance, it also practices green and low-carbon principles, reducing consumable consumption and energy loss. Attached Figure Description

[0017] Figure 1 This is a flowchart illustrating a dual-channel power line carrier communication and service scheduling method in one embodiment. Figure 2 This is a schematic diagram of the communication system in one embodiment; Figure 3This is a schematic diagram showing the connection between the first carrier loop and the second carrier loop in one embodiment; Figure 4 This is a schematic diagram illustrating the connection of multiple communication slave devices simultaneously accessing the first carrier circuit or the second carrier circuit in one embodiment. Detailed Implementation

[0018] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments. The step numbers in the following embodiments are only for ease of explanation and do not limit the order of the steps. The execution order of each step in the embodiments can be adapted according to the understanding of those skilled in the art.

[0019] The terminology used in the embodiments of this application is for the purpose of describing particular embodiments only and is not intended to limit the embodiments of this application. The singular forms “a,” “the,” and “the” used in the embodiments of this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used herein refers to and includes any or all possible combinations of one or more of the associated listed items.

[0020] In the following description, when referring to the accompanying drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims. In the description of this application, it should be understood that the terms "first," "second," "third," etc., are used only to distinguish similar objects and are not necessarily used to describe a specific order or sequence, nor should they be construed as indicating or implying relative importance. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0021] Furthermore, in the description of this application, unless otherwise stated, "multiple" means two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone. The character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0022] Example 1 In this embodiment, as Figure 1 This paper presents a green and low-carbon dual-channel power line carrier communication and service scheduling method, which is applied to a communication system.

[0023] In this embodiment, as Figures 2-4As shown, the communication system includes a communication host and at least one communication slave connected via an AC power line. The communication host is located in the centralized procurement terminal and includes a first host carrier unit (C1) and a second host carrier unit (C2). The communication slave is located in the inverter and includes a first slave carrier unit (S1) and a second slave carrier unit (S2).

[0024] In this embodiment, the dual-channel power line carrier communication and service scheduling method includes the following steps: S100 Initialization: The first host carrier unit and the second host carrier unit of the control communication host operate in the first frequency band and the second frequency band respectively, and the first slave carrier unit and the second slave carrier unit of the control communication slave are coupled with the first host carrier unit and the second host carrier unit respectively, thereby forming the first carrier loop and the second carrier loop respectively. S200, Service Scheduling and Transmission: Obtain service data to be transmitted, including first type data with first service characteristics and second type data with second service characteristics; allocate the first type data to the first carrier circuit for transmission, and allocate the second type data to the second carrier circuit for transmission; S300, Link Quality Monitoring and Switching: Real-time monitoring of link quality parameters of the first carrier loop and the second carrier loop; when it is determined that the link quality of either the first carrier loop or the second carrier loop is lower than a preset quality threshold, the service data transmitted on the current link is switched to another transmission link for transmission.

[0025] In this embodiment, in step S200: The first service characteristic is that the data volume is greater than the preset traffic threshold, and the first type of data is device status inspection data at the second or minute level; the second service characteristic is that the transmission latency requirement is lower than the preset latency threshold, and the second type of data is device control commands at the millisecond level.

[0026] In this embodiment, step S200 specifically includes: Set the highest transmission priority for the second type of data; Based on the highest transmission priority, transmission time slot resources are dynamically allocated to the second carrier loop to ensure that the end-to-end transmission delay of the second type of data does not exceed 60ms.

[0027] In a specific embodiment, the first type of data refers to the second-level MBUS (Meter-Bus) patrol data, and the first carrier loop is used to carry large amounts of periodically collected data such as inverter operating status and power generation.

[0028] In a specific embodiment, the second type of data refers to 60ms-level GOOSE (Generic Object Oriented Substation Event) control commands, which are allocated to the second carrier loop for transmission. The second carrier loop has a higher priority and is allocated transmission time slots first, ensuring that the transmission delay of the control commands is ≤60ms, meeting the safety control requirements of the power station, and ensuring the efficient and stable operation of the photovoltaic power station.

[0029] In this embodiment, in step S300, the link quality parameters include one or more of the following: signal-to-noise ratio, packet loss rate, and transmission delay. The preset quality thresholds include signal-to-noise ratio threshold, packet loss rate threshold, and transmission delay threshold.

[0030] When it is determined that the link quality of either the first carrier loop or the second carrier loop is lower than a preset quality threshold, specifically: If the signal-to-noise ratio of either the first carrier loop or the second carrier loop is found to be below 20dB, the packet loss rate is above 1%, or the transmission delay is abnormal, then the link quality is determined to be below the preset quality threshold.

[0031] In this embodiment, the signal-to-noise ratio threshold of 20dB and the packet loss rate threshold of 1% are empirical values ​​determined after extensive experimental testing in a typical photovoltaic power station power line environment to ensure the reliability of service transmission.

[0032] In this embodiment, in step S300, the total time from determining that the link quality is lower than the preset threshold to completing the service data switching does not exceed 50ms; if it exceeds 50ms, the transmission delay is considered abnormal.

[0033] Specifically, if no reply frame is received within 50ms after the second or first carrier loop transmits data, the system immediately switches to the corresponding first or second carrier loop. Furthermore, a switching time of ≤50ms satisfies the 60ms end-to-end transmission requirement of the GOOSE control command, leaving a 10ms processing margin.

[0034] In this embodiment, step S100 specifically includes: The carrier signals generated by the first host carrier unit and the second host carrier unit are coupled to the AC power line side with a voltage higher than 800VAC through the built-in isolation coupling circuit.

[0035] Specifically, the first host carrier unit, the second host carrier unit, the first slave carrier unit, and the second slave carrier unit all include isolation coupling circuits, which can be directly coupled to AC 800~1000V AC power lines without the need to lay additional RS40085 communication cables, greatly reducing the wiring cost, material consumption, and maintenance difficulty of photovoltaic power stations.

[0036] In one possible embodiment, the isolation coupling circuit uses a capacitor with a withstand voltage rating of not less than 2.5kV for AC coupling, and is equipped with surge protection devices (such as TVS diodes) and filtering circuits to ensure that the carrier signal can be safely and effectively injected into the AC power line, while isolating the high voltage from the downstream low-voltage communication circuit. The capacitor value and withstand voltage rating are selected adaptably according to the actual operating conditions such as voltage level and communication frequency band.

[0037] In this embodiment, the dual-channel power line carrier communication and service scheduling method further includes the following steps: Step S400, Multi-node network scheduling: When there are multiple communication slaves, different transmission time slots are allocated to each communication slave that is simultaneously connected to the first carrier circuit or the second carrier circuit. Based on the allocated transmission time slots, each communication slave is scheduled to transmit data within its assigned time slot to avoid data conflicts between multiple nodes.

[0038] Specifically, when multiple communication slaves simultaneously access the first carrier loop or the second carrier loop, the CSMA / CA (Carrier Sense Multiple Access with Collision Avoidance) algorithm is used to implement time slot scheduling and collision avoidance mechanism. This can support multiple communication slaves to communicate online at the same time, avoid data transmission conflicts between multiple nodes, and is suitable for the networking needs of large-scale ground-mounted photovoltaic power plants.

[0039] Specifically, when multiple communication slaves simultaneously access the first or second carrier loop, a hybrid protocol of TDMA (Time Division Multiple Access) time slot scheduling and CSMA / CA conflict avoidance is adopted; high-priority GOOSE control services adopt TDMA exclusive transmission with pre-allocated fixed time slots by the master station, and MBUS patrol services adopt CSMA / CA carrier listening backoff transmission within a limited time slot window. The communication host can dynamically allocate and reclaim time slots to adapt to node additions and offline topology changes.

[0040] In this embodiment, the first carrier circuit and the second carrier circuit are coupled to different phase line combinations of the AC power line.

[0041] In this embodiment, the AC power line includes phase A, phase B, and phase C, and the phase combination includes any two of phase A, phase B, and phase C.

[0042] In this embodiment, as Figures 2-4 As shown, the multi-phase line includes phase A line ( Figure 2 (abbreviated as A) and B phase lines ( Figure 2 (abbreviated as letter B) and C phase lines ( Figure 2 (Abbreviated as C). Both the first and second phase line combinations consist of any two combinations of phase A, phase B, and phase C lines, and the multi-phase lines constituting the first and second phase line combinations are not exactly the same. By configuring different phase line combinations, it is possible to adapt to different AC power line topologies, thus improving applicability.

[0043] In one specific embodiment, the first phase line combination is a combination of phase A line and phase B line, and the second phase line combination is a combination of phase B line and phase C line, that is, the first phase line combination and the second phase line combination share the phase B line.

[0044] In this embodiment, the first frequency band and the second frequency band are non-overlapping power line carrier communication frequency bands, and the frequency interval between the two frequency bands is not less than 0.5MHz, thereby effectively avoiding mutual interference between the first carrier loop and the second carrier loop.

[0045] In one specific embodiment, the first frequency band is 2.5MHz to 5.7MHz, and the second frequency band is 6.2MHz to 8.4MHz.

[0046] The above is a detailed description of the preferred embodiments of the present invention. However, the present invention is not limited to the embodiments described. Those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of the present invention. All such equivalent modifications or substitutions are included within the scope defined by the claims of this application.

Claims

1. A green and low-carbon dual-channel power line carrier communication and service scheduling method, characterized in that, The dual-channel power line carrier communication and service scheduling method is applied to a communication system, which includes a communication host and at least one communication slave connected via an AC power line. The communication host has a built-in first host carrier unit and a second host carrier unit, and the communication slave has a built-in first slave carrier unit and a second slave carrier unit. The dual-channel power line carrier communication and service scheduling method includes the following steps: S100. Initialization: Control the first host carrier unit and the second host carrier unit of the communication host to work in the first frequency band and the second frequency band respectively, and control the first slave carrier unit and the second slave carrier unit of the communication slave to couple with the first host carrier unit and the second host carrier unit respectively, thereby forming the first carrier loop and the second carrier loop respectively. S200, Service Scheduling and Transmission: Obtain service data to be transmitted, the service data including a first type of data with a first service characteristic and a second type of data with a second service characteristic; allocate the first type of data to the first carrier circuit for transmission, and allocate the second type of data to the second carrier circuit for transmission; S300, Link Quality Monitoring and Switching: Real-time monitoring of link quality parameters of the first carrier loop and the second carrier loop; when it is determined that the link quality of either the first carrier loop or the second carrier loop is lower than a preset quality threshold, the service data transmitted on the current link is switched to another transmission link for transmission. S400, multi-node network scheduling: When there are multiple communication slaves, different transmission time slots are allocated to each communication slave that is simultaneously connected to the first carrier circuit or the second carrier circuit. Based on the allocated transmission time slots, each communication slave is scheduled to transmit data within its assigned time slot to avoid data conflicts between multiple nodes. The first carrier circuit and the second carrier circuit are coupled to different phase line pairs of the AC power line; The AC power lines include phase A, phase B, and phase C lines, and the phase combination includes any two of phase A, phase B, and phase C lines.

2. The dual-channel power line carrier communication and service scheduling method according to claim 1, characterized in that, In step S200: The first business feature is that the data volume is greater than the preset traffic threshold, and the first type of data is device status inspection data at the second or minute level; The second service feature is that the transmission latency requirement is lower than a preset latency threshold, and the second type of data is a millisecond-level device control command.

3. The dual-channel power line carrier communication and service scheduling method according to claim 2, characterized in that, Step S200 specifically includes: Set the highest transmission priority for the second type of data; Based on the highest transmission priority, transmission time slot resources are dynamically allocated to the second carrier loop to ensure that the end-to-end transmission delay of the second type of data does not exceed 60ms.

4. The dual-channel power line carrier communication and service scheduling method according to claim 1, characterized in that, In step S300, the link quality parameters include one or more of the following: signal-to-noise ratio, packet loss rate, and transmission delay. The preset quality thresholds include a signal-to-noise ratio threshold, a packet loss rate threshold, and a transmission delay threshold. Specifically, when the link quality of either the first carrier loop or the second carrier loop is determined to be lower than a preset quality threshold: When the signal-to-noise ratio of a carrier loop is found to be below 20dB, the packet loss rate is found to be above 1%, or the transmission delay is abnormal, the link quality of that loop is determined to be below the preset quality threshold.

5. The dual-channel power line carrier communication and service scheduling method according to claim 4, characterized in that, In step S300, the total time from determining that the link quality is lower than the preset threshold to completing the service data switch does not exceed 50ms.

6. The dual-channel power line carrier communication and service scheduling method according to claim 1, characterized in that, Step S100 specifically includes: The carrier signals generated by the first host carrier unit and the second host carrier unit are coupled to the AC power line side with a voltage higher than 800VAC through the built-in isolation coupling circuit.

7. The dual-channel power line carrier communication and service scheduling method according to any one of claims 1-6, characterized in that, The first frequency band and the second frequency band are non-overlapping power line carrier communication frequency bands, and the frequency interval between the two frequency bands is not less than 0.5MHz.

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