A green and low-carbon power line carrier photovoltaic communication system

Abstract

This invention provides a green and low-carbon power line carrier photovoltaic communication system, relating to the field of power line carrier communication technology. This invention establishes independent communication channels on two non-overlapping frequency bands—a first carrier loop and a second carrier loop—achieving isolated transmission and redundant backup of service data. The service scheduling module allocates services of different priorities to different communication channels, ensuring timely transmission of low-latency control commands while meeting the bandwidth requirements of large-volume data acquisition. The synergistic effect of these technical features significantly improves the reliability, real-time performance, and anti-interference capability of the power line carrier photovoltaic communication system, while utilizing existing high-voltage AC power lines for communication, reducing wiring costs and maintenance difficulty.

Description

Technical Field

[0001] This utility model relates to the field of power line carrier communication technology, and in particular to a green and low-carbon power line carrier photovoltaic communication system. Background Technology

[0002] As the core carrier of green and low-carbon energy, the large-scale and efficient operation of photovoltaic power plants has become an industry trend. The communication system between string inverters and transformer substations / centralized procurement terminals is the core link to ensure the green and efficient operation of photovoltaic power plants and realize the efficient use of energy.

[0003] In existing photovoltaic power plants, reliable communication between string inverters and centralized terminals is crucial for the efficient operation of the plant. Traditional solutions mostly use RS485 wired communication, which requires additional communication cables, resulting in 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, leading to high carbon emissions. On the other hand, the wear and tear, aging, and replacement of cables during long-term operation further increase energy consumption and environmental pollution, which is inconsistent with the green and low-carbon development goals of photovoltaic power plants. Power line carrier (PLC) communication utilizes existing power lines to transmit data, avoiding additional wiring and representing a more advantageous alternative.

[0004] However, existing PLC communication solutions for photovoltaic power plants are mostly single-channel designs, which have the following problems: weak anti-interference capability, making it difficult to cope with power line noise and load changes; inability to distinguish service priorities, failing to simultaneously meet the needs of large-volume data acquisition and low-latency control command transmission; and lack of redundancy mechanisms, resulting in insufficient communication reliability. Some solutions have attempted to adopt single-band dual-loop or dual-band single-loop designs, but these still cannot completely solve the above problems.

[0005] Therefore, there is a need in the field for a power line carrier communication system that can achieve dual-band dual-loop redundant transmission while ensuring communication reliability and real-time performance. Utility Model Content

[0006] In view of this, the core technical problem to be solved by this utility model is: how to provide a power line carrier photovoltaic communication system that can simultaneously meet the transmission needs of different priority services in photovoltaic power plants, reduce wiring costs and maintenance difficulties while ensuring communication reliability and real-time performance, thereby improving the overall performance of power line carrier communication in photovoltaic power plants.

[0007] On one hand, this utility model provides a green and low-carbon power line carrier photovoltaic communication system, including: a communication host, including a first host carrier unit and a second host carrier unit; a communication slave, including a first slave carrier unit and a second slave carrier unit; a high-voltage AC power line, wherein the communication host and the communication slave are connected through the high-voltage AC power line, the high-voltage AC power line including a multi-phase line, the multi-phase line including a first phase line combination and a second phase line combination; wherein, the first host carrier unit and the first slave carrier unit are coupled together through the first phase line combination to form a first carrier loop, the first carrier loop operating in a first frequency band; the second host carrier unit and the second slave carrier unit are coupled together through the second phase line combination to form a second carrier loop, the second carrier loop operating in a second frequency band that does not overlap with the first frequency band; the first host carrier unit, the second host carrier unit, the first slave carrier unit, and the second slave carrier unit all include a service scheduling module and a high-voltage isolation coupling circuit, the service scheduling module is used to allocate service data of different priorities to the first carrier loop and / or the second carrier loop; the high-voltage isolation coupling circuit is used to couple carrier signals to the high-voltage AC power line.

[0008] Optionally, the multiphase line includes phase A, phase B and phase C; the first phase line combination and the second phase line combination are each composed of any two combinations of phase A, phase B and phase C.

[0009] Optionally, the frequency interval between the first frequency band and the second frequency band is not less than 0.5MHz.

[0010] Optionally, the first frequency band is 2.5MHz to 5.7MHz, and the second frequency band is 6.2MHz to 8.4MHz.

[0011] Optionally, the service scheduling module is used to allocate second-level MBUS patrol data to the first carrier loop, allocate 60ms-level GOOSE control commands to the second carrier loop, and set the highest priority for the GOOSE control commands.

[0012] Optionally, it also includes a link quality detection and switching module, used to monitor the link quality of the first carrier loop and / or the second carrier loop and trigger service data switching when the quality deteriorates.

[0013] Optionally, the link quality detection and switching module monitors link quality metrics including signal-to-noise ratio (SNR) and packet loss rate, and triggers switching when the SNR is below 20dB or the packet loss rate is above 1%.

[0014] Optionally, when multiple communication slaves simultaneously access the first carrier circuit or the second carrier circuit, data transmission conflicts among the multiple communication slaves can be avoided through time slot scheduling and conflict avoidance mechanisms.

[0015] Optionally, the first master carrier unit and the second master carrier unit, as well as the first slave carrier unit and the second slave carrier unit, are connected via a serial communication interface for data coordination and redundancy backup.

[0016] The implementation of this utility model has the following beneficial effects: This utility model establishes independent communication channels on two non-overlapping frequency bands—the first carrier circuit and the second carrier circuit—achieving isolated transmission and redundant backup of service data. The service scheduling module allocates services of different priorities to different communication channels, ensuring timely transmission of low-latency control commands while meeting the bandwidth requirements of large-volume data acquisition. Under the synergistic effect of the above technical features, the reliability, real-time performance, and anti-interference capability of the power line carrier photovoltaic communication system are significantly improved. Simultaneously, utilizing existing high-voltage AC power lines for communication reduces wiring costs and maintenance difficulty, decreases material consumption and energy loss, and helps photovoltaic power plants achieve green and efficient operation, which is more in line with the concept of green and low-carbon development. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of a power line carrier photovoltaic communication system based on dual-band dual-loop in one embodiment;

[0018] Figure 2 This is a schematic diagram showing the connection between the first carrier loop and the second carrier loop in one embodiment;

[0019] Figure 3 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

[0020] 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.

[0021] 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.

[0022] 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.

[0023] 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.

[0024] Example 1

[0025] In this embodiment, as Figure 1 The green and low-carbon power line carrier photovoltaic communication system shown includes a communication host installed in a centralized procurement terminal. The communication host includes a first host carrier unit (C1) and a second host carrier unit (C2).

[0026] The communication slave unit is located inside the inverter and includes a first slave carrier unit (S1) and a second slave carrier unit (S2).

[0027] A high-voltage AC power line is used to connect the communication host and the communication slave. The high-voltage AC power line includes a multi-phase line, which includes a combination of the first phase line and a combination of the second phase line.

[0028] The first master carrier unit and the first slave carrier unit are coupled together via a first phase line to form a first carrier loop, which operates in a first frequency band. The second master carrier unit and the second slave carrier unit are coupled together via a second phase line to form a second carrier loop, which operates in a second frequency band that does not overlap with the first frequency band. Each of the first master carrier unit, the second master carrier unit, the first slave carrier unit, and the second slave carrier unit includes a service scheduling module and a high-voltage isolation coupling circuit. The service scheduling module is used to allocate service data of different priorities to the first carrier loop and / or the second carrier loop. The high-voltage isolation coupling circuit is used to couple the carrier signal to a high-voltage AC power line.

[0029] Specifically, the first carrier circuit and the second carrier circuit operate in different frequency bands and are coupled to different phase line combinations, forming a redundant communication link with independent dual communication channels. This significantly improves the reliability of the power line carrier photovoltaic communication system. When any communication channel fails, it can seamlessly switch to the other channel, thereby ensuring the continuity of communication, ensuring the stable operation of the photovoltaic power station, and improving energy utilization efficiency.

[0030] In this embodiment, the first host carrier unit, the second host carrier unit, the first slave carrier unit, and the second slave carrier unit all include a service scheduling module and a high-voltage isolation coupling circuit, so that they can be directly coupled to the AC 800~1000V high-voltage AC power line without the need to lay additional RS485 communication cables, which greatly reduces the wiring cost, material consumption, and maintenance difficulty of the photovoltaic power station.

[0031] In this embodiment, as Figures 1-3 As shown, multi-phase lines include phase A lines ( Figure 1 (abbreviated as A and B phase lines) Figure 1 (abbreviated as B) and C phase lines ( Figure 1 (Abbreviated as letter 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 entirely the same. By configuring different phase line combinations, it is possible to adapt to different high-voltage AC power line topologies, thus improving applicability.

[0032] 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.

[0033] In this embodiment, the first host carrier unit, the second host carrier unit, the first slave carrier unit, and the second slave carrier unit are all composed of two carrier chips.

[0034] In this embodiment, the high-voltage isolation coupling circuit includes a high-voltage coupling capacitor, an isolation transformer, and a surge protection device, thereby safely coupling the low-voltage carrier signal generated by the carrier chip to the high-voltage power line while blocking damage to the communication circuit from the power frequency high voltage. The high-voltage coupling capacitor, isolation transformer, and surge protection device are all commercially available components, and their structure, principle, and connection method are not described in detail here.

[0035] In this embodiment, the frequency interval between the first frequency band and the second frequency band is not less than 0.5MHz. By setting a frequency interval of not less than 0.5MHz, mutual interference between the first carrier loop and the second carrier loop can be effectively avoided.

[0036] 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. The frequencies of the first and second frequency bands are selected from commonly used frequency bands for power line carrier communication, and their interval is greater than 0.5MHz, which complies with the frequency band isolation requirements in standards such as IEEE 1901 and can effectively avoid inter-band harmonic interference.

[0037] In this embodiment, the service scheduling module has a built-in scheduling method based on MCU (Microcontroller Unit). The specific scheduling method based on MCU is as follows: MBUS (Meter-Bus) inspection data with a transmission period of seconds is allocated to the first carrier loop. The first carrier loop is used to carry periodically collected large amounts of data such as inverter operating status and power generation. GOOSE (Generic Object Oriented Substation Event) control commands with an end-to-end transmission delay of ≤60ms are allocated to the second carrier loop, and the GOOSE control commands are set to the highest priority, so that 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, ensuring the efficient and stable operation of the photovoltaic power station, and improving energy utilization efficiency.

[0038] In this embodiment, the MCU can be an external microcontroller or a processor integrated into the communication host.

[0039] In this embodiment, the green and low-carbon power line carrier photovoltaic communication system also includes a link quality detection and switching module, which is used to monitor the link quality of the first carrier loop and / or the second carrier loop and trigger service data switching when the quality deteriorates. Through the link quality monitoring and automatic switching functions, seamless redundancy backup is achieved.

[0040] In this embodiment, the link quality detection and switching module monitors link quality indicators including signal-to-noise ratio (SNR) and packet loss rate. It triggers switching when the SNR falls below 20dB or the packet loss rate exceeds 1%, thus providing a reliable switching triggering mechanism. When the first carrier loop experiences a decrease in SNR, a packet loss rate exceeding the threshold, or abnormal transmission delay due to line noise interference, the centralized acquisition terminal can automatically switch the MBUS inspection data temporarily to the second carrier loop for transmission. When the second carrier loop fails, it can also automatically switch the GOOSE control command to the first carrier loop, with a switching time ≤50ms, achieving seamless redundancy backup and ensuring communication continuity and stability.

[0041] Specifically, the signal-to-noise ratio threshold of 20dB and the packet loss rate threshold of 1% are set based on the typical characteristics of power line noise in photovoltaic power plants, and are empirical values ​​for effective early warning of link quality degradation.

[0042] In this embodiment, a switching time of ≤50ms means that if no reply frame is received within 50ms after the second carrier loop or the first carrier loop sends data, the system immediately switches to the first carrier loop or the second carrier loop accordingly. Furthermore, a switching time of ≤50ms also satisfies the 60ms end-to-end transmission requirement of the GOOSE control command, reserving a 10ms processing margin.

[0043] In this embodiment, when multiple communication slaves simultaneously access the first carrier circuit or the second carrier circuit, data transmission conflicts between the multiple communication slaves are avoided through time slot scheduling and conflict avoidance mechanisms. These time slot scheduling and conflict avoidance mechanisms support networking of multiple communication slaves while also preventing data transmission conflicts.

[0044] 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.

[0045] 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 host, 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.

[0046] In this embodiment, the first master carrier unit and the second master carrier unit, as well as the first slave carrier unit and the second slave carrier unit, are connected via a serial communication interface for data coordination and redundancy backup. This inter-unit data coordination and redundancy backup mechanism further improves the system's reliability.

[0047] In this embodiment, the serial communication interface is RS485.

[0048] The above is a detailed description of the preferred embodiments of the present utility model. However, the present utility model is not limited to the described embodiments. Those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of the present utility model. All such equivalent modifications or substitutions are included within the scope defined by the claims of this application.

Claims

1. A green low-carbon power line carrier photovoltaic communication system, characterized in that, include: The communication host includes a first host carrier unit and a second host carrier unit; The communication slave unit includes a first slave carrier unit and a second slave carrier unit; A high-voltage AC power line is provided, through which the communication host and the communication slave are connected. The high-voltage AC power line includes a multi-phase line, which includes a first phase line combination and a second phase line combination. The first master carrier unit and the first slave carrier unit are coupled together via the first phase line combination to form a first carrier loop, which operates in a first frequency band. The second master carrier unit and the second slave carrier unit are coupled together via the second phase line combination to form a second carrier loop, which operates in a second frequency band that does not overlap with the first frequency band. Each of the first master carrier unit, the second master carrier unit, the first slave carrier unit, and the second slave carrier unit includes a service scheduling module and a high-voltage isolation coupling circuit. The service scheduling module is used to allocate service data of different priorities to the first carrier loop and / or the second carrier loop. The high-voltage isolation coupling circuit is used to couple the carrier signal to the high-voltage AC power line.

2. The power line carrier photovoltaic communication system of claim 1, wherein, The multiphase line includes phase A, phase B, and phase C; the first phase line combination and the second phase line combination are each composed of any two combinations of phase A, phase B, and phase C.

3. The power line carrier photovoltaic communication system of claim 1, wherein, The frequency interval between the first frequency band and the second frequency band is not less than 0.5MHz.

4. The power line carrier photovoltaic communication system of claim 3, wherein, The first frequency band is 2.5MHz to 5.7MHz, and the second frequency band is 6.2MHz to 8.4MHz.

5. The power line carrier photovoltaic communication system according to claim 1, characterized in that, The service scheduling module is used to allocate second-level MBUS patrol data to the first carrier circuit, allocate 60ms-level GOOSE control commands to the second carrier circuit, and set the highest priority for the GOOSE control commands.

6. The power line carrier photovoltaic communication system according to claim 1, characterized in that, It also includes a link quality detection and switching module, which is used to monitor the link quality of the first carrier loop and / or the second carrier loop and trigger service data switching when the quality deteriorates.

7. The power line carrier photovoltaic communication system according to claim 6, characterized in that, The link quality detection and switching module monitors link quality indicators including signal-to-noise ratio (SNR) and packet loss rate, and triggers switching when the SNR is below 20dB or the packet loss rate is above 1%.

8. The power line carrier photovoltaic communication system according to claim 1, characterized in that, When multiple communication slave devices are simultaneously connected to the first carrier circuit or the second carrier circuit, data transmission conflicts among the multiple communication slave devices are avoided through time slot scheduling and conflict avoidance mechanisms.

9. The power line carrier photovoltaic communication system according to claim 1, characterized in that, The first host carrier unit and the second host carrier unit, as well as the first slave carrier unit and the second slave carrier unit, are connected via a serial communication interface for data coordination and redundancy backup.

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