Anti-reflux control system based on net-zero control

Abstract

This invention discloses an anti-reverse current control system based on net-zero control, relating to the field of anti-reverse current technology. It includes a communication connection establishment module, a power grid data monitoring and transmission module, a power regulation execution module, and a database. The communication connection establishment module acquires communication environment data from the target power station, analyzes and adapts to suitable communication methods including RS485, WiFi UDP, or Sub-1G, and establishes a bidirectional link. The power grid data monitoring and transmission module acquires real-time power data from each inverter, assesses whether power changes require feedback, and transmits data if feedback is needed. The power regulation execution module, after receiving data, calculates the regulation ratio based on the rated power and dynamically analyzes the regulation value. The system is adaptable to multiple scenarios, improves power regulation accuracy and response speed, and achieves precise anti-reverse current control.

Description

Technical Field

[0001] This invention relates to the field of anti-backflow technology, and more specifically to an anti-backflow control system based on net zero control. Background Technology

[0002] As the penetration rate of new energy power plants increases, the volatility of their power generation and the randomness of load power consumption can easily lead to power imbalance in the power grid. When the power generation of the power plant exceeds the local load demand, the excess power will be fed back into the power grid, which may cause voltage fluctuations, frequency deviations, and even affect the stability of the relay protection system. Therefore, a reverse current control system based on net zero control is needed.

[0003] Existing technology, such as the invention application patent with publication number CN110266052A, discloses a fast frequency regulation device and method applicable to photovoltaic power plants. This device is equipped with: an analog signal acquisition unit for acquiring real-time voltage and current at the grid connection point; a frequency and power response control unit for calculating the real-time frequency and power of the power grid based on the acquired real-time voltage and current; and a frequency control management unit for controlling and adjusting the active power of each inverter in operation within the photovoltaic power plant based on the real-time frequency and power of the power grid, thereby achieving fast frequency regulation of the power grid. This invention, based on the existing equipment in a photovoltaic power plant, achieves fast frequency regulation of the power grid by adding a frequency control management unit and increasing or decreasing the active power of the adjustable inverters in operation. Because the inverter response time is very short and the adjustment is rapid, this invention has strong practicality.

[0004] Regarding the above solutions, the inventors of this application have discovered at least the following technical problems with the above technologies: 1. Traditional anti-backflow systems mostly rely on a single communication solution: When using only RS485 wired communication, in scenarios where wiring is difficult, such as distributed photovoltaic rooftops and large ground power stations, hundreds of meters of additional cable need to be laid, which not only increases the installation cost by more than 50%, but also leads to an annual failure rate of more than 15% due to the large number of cable joints and susceptibility to corrosion; when using a simple wireless solution, in environments with strong electromagnetic interference, such as industrial plants and substations, the high-frequency noise interference generated by motors and transformers often results in a communication packet loss rate of more than 10%, and in extreme cases, even a continuous 30-second data interruption, causing the anti-backflow control to fail; moreover, a single communication method cannot cover diverse scenarios—for distributed power stations, simple wireless signals attenuate severely, resulting in insufficient coverage; wired communication leads to a surge in maintenance difficulty due to cable tangling, and cannot meet the stability requirements of different scenarios.

[0005] 2. Traditional systems employ a crude strategy of "average distribution of regulation" without considering the differences in inverter rated power. For example, a power station contains one 5kW low-power inverter and one 50kW high-power inverter. When the total power to be regulated is 30kW, average distribution will cause the low-power inverter to output 15kW, triggering overload protection shutdown, while the high-power inverter will only output 15kW, resulting in a large amount of regulation redundancy. More importantly, when inverters are added or removed from the power station, the traditional system does not update the total rated power in real time, and the regulation ratio still uses the old parameters, resulting in a regulation deviation of more than 20%, which in turn causes the grid voltage fluctuation to reach ±8%, affecting the lifespan of surrounding electrical equipment.

[0006] 3. Traditional solutions typically have sampling periods exceeding 500ms. In scenarios where cloud cover causes a sudden 20% drop in photovoltaic output within one second, or where loads are suddenly switched on or off, they cannot capture power fluctuations in a timely manner. Adjustment delays often exceed one second; when reverse current power reaches 10% of rated power, it takes more than 1.5 seconds to begin adjustment, resulting in reverse current duration exceeding two seconds, potentially triggering malfunctions in grid relay protection. Furthermore, there is a lack of adjustment effect verification mechanisms—for example, if an inverter fails to execute adjustment commands due to a fault, the traditional system cannot detect this, leading to a total adjustment deviation exceeding 30%, still posing a reverse current risk. This lack of a closed-loop mechanism—"sampling lag - adjustment delay - no verification"—means that reverse current power control accuracy can only be maintained at around ±10% of rated power, far from meeting the stringent ±2% accuracy requirements of the grid under high renewable energy penetration, easily causing grid frequency deviation and threatening the safe and stable operation of the grid. Summary of the Invention

[0007] To address the aforementioned technical shortcomings, the purpose of this invention is to provide an anti-backflow control system based on net zero control.

[0008] To solve the above technical problems, the present invention adopts the following technical solution: The present invention provides an anti-reverse current control system based on net zero control, including: a communication connection establishment module: used to deploy NZC adapted to multiple scenarios in the target power station, analyze the corresponding adaptive communication method of the target power station by acquiring the communication environment data of the target power station, and establish a bidirectional communication link between the NZC of the target power station and each inverter.

[0009] Grid Data Monitoring and Transmission Module: Used to acquire grid power data corresponding to each inverter in the target power station in real time through NZC, evaluate whether the grid power change corresponding to each inverter in the target power station needs to be fed back, and if the grid power change corresponding to a certain inverter in the target power station needs to be fed back, then the power data of that inverter in the target power station will be transmitted to the grid of that inverter through the established communication link.

[0010] Power regulation execution module: After each inverter in the target power station receives the grid power data transmitted by NZC, it obtains the rated power parameters corresponding to each inverter in the target power station, and then analyzes the power regulation ratio corresponding to each inverter in the target power station. Based on the power regulation ratio corresponding to the inverter in the target power station, it dynamically analyzes the power regulation value corresponding to the inverter in the target power station.

[0011] The beneficial effects of this invention are as follows: 1. In the embodiments of this invention, firstly, the intelligent adaptability of the communication method is significantly enhanced. By quantitatively analyzing environmental data such as wiring difficulty coefficient, local area network packet loss rate, and device distribution density, the system can automatically match the optimal communication method, solving the limitations of traditional single communication methods in complex scenarios. For example, distributed power stations with difficult wiring can prioritize Sub-1G wireless communication, while rooftop power stations with dense equipment can use WiFiUDP communication to simplify wiring, ensuring that the communication latency is stable within 100ms-500ms under different environments, and the data transmission success rate exceeds 99.9%, greatly reducing the risk of control failure due to communication interruption.

[0012] 2. In this embodiment of the invention, the accuracy and dynamic response capability of power regulation are significantly improved. The system calculates the regulation value based on the rated power ratio of the inverter, avoiding the problems of overload of low-power equipment and regulation redundancy of high-power equipment caused by the traditional average distribution strategy. By updating the total rated power in real time and combining dynamic verification of the smooth effective power value, it ensures that the regulation amount is highly matched with the power demand of the grid. For example, when the grid needs to increase the power by 30kW, the 5kW and 50kW inverters can be adjusted to 3kW and 27kW respectively in a ratio of 1:10, without overload or redundancy, and the regulation response time is ≤1 second. The reverse current power control accuracy can reach within ±2% of the rated power, meeting the stringent stability requirements of the grid under the high penetration rate of new energy.

[0013] 3. Finally, in this embodiment of the invention, the system's reliability and traceability are significantly optimized. Through the closed-loop control logic of "collection-analysis-adjustment-feedback," each step of the operation is verified with data, avoiding loss of control caused by "over-adjustment," "under-adjustment," or communication abnormalities. At the same time, the dual data storage mechanism of local and cloud supports full traceability of power curves and adjustment events. When communication is interrupted or adjustment is abnormal, alarm logs are automatically generated. Maintenance personnel can monitor the equipment status in real time through the APP, improving fault diagnosis efficiency by more than 60% and significantly reducing maintenance costs and grid operation risks. Attached Figure Description

[0014] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0015] Figure 1 This is a schematic diagram of the system module connections of the present invention. Detailed Implementation

[0016] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0017] Examples of embodiments of the present invention Figure 1 As shown, the anti-reverse flow control system based on net-zero control includes: a communication connection establishment module, a power grid data monitoring and transmission module, a power regulation execution module, and a database.

[0018] The power grid data monitoring and transmission module is connected to the communication connection establishment module and the power regulation execution module, respectively, and the database is connected to the communication connection establishment module.

[0019] It should be noted that the database is used to store the communication environment adaptation value range corresponding to each adapted communication method.

[0020] Communication connection establishment module: used to deploy NZC adapted to multiple scenarios in the target power station. By acquiring the communication environment data of the target power station, it analyzes the corresponding communication method of the target power station and establishes a bidirectional communication link between the NZC of the target power station and each inverter.

[0021] In a specific embodiment, the analysis of the adaptive communication method corresponding to the target power station is carried out as follows: the adaptation value of the communication environment corresponding to the target power station is analyzed, and the adaptation value of the communication environment corresponding to the target power station is compared with the adaptation value range of each adaptation communication method in the database. If the adaptation value of the communication environment corresponding to the target power station is within the adaptation value range of a certain adaptation communication method in the database, then the adaptation communication method in the database is recorded as the adaptation communication method corresponding to the target power station.

[0022] The compatible communication methods include RS485 wired communication, WiFi UDP communication, and Sub-1G wireless communication.

[0023] In a specific embodiment, the analysis of the communication environment adaptation value corresponding to the target power station is carried out as follows: the communication environment data corresponding to the target power station is obtained, including the wiring difficulty coefficient, local area network packet loss rate and device distribution density, and normalized. At the same time, the data is substituted into the communication environment adaptation value analysis model to obtain the communication environment adaptation value corresponding to the target power station.

[0024] It should be noted that the analysis process for the communication environment adaptation value corresponding to the target power station is as follows: the cabling difficulty coefficient, LAN packet loss rate, and device distribution density corresponding to the target power station are respectively denoted as... , and Substitute into the analysis formula: In the process, the communication environment adaptation value corresponding to the target power station is obtained. .

[0025] In a specific embodiment, the bidirectional communication link between the NZC and each inverter corresponding to the target power station is established as follows: A1. If the adaptive communication method corresponding to the target power station is RS485 wired communication, then shielded twisted pair cables are used to connect the NZC and the inverter through terminal blocks. When wiring, a distance of ≥30cm should be maintained from the power lines. The joints are crimped with cold-pressed terminals and covered with insulating tubes. 120Ω terminating resistors are installed at both ends to ensure stable transmission.

[0026] A2. If the target power station is compatible with WiFi UDP communication, then connect the NZC and the inverter to the same local area network. Enable UDP multicast function on the NZC. After the inverter starts up, it will automatically scan and join the multicast group, dynamically obtain an IP address through DHCP, and maintain a communication delay of ≤100ms.

[0027] A3. If the target power station is compatible with Sub-1G wireless communication, then configure Sub-1G modules of the same frequency band on the NZC and the inverter. The NZC is set as the master node with a fixed frequency and code rate, and the inverter is set as the slave node to automatically synchronize parameters. The anti-interference capability is enhanced by frequency hopping technology of 10 times per second.

[0028] Grid Data Monitoring and Transmission Module: Used to acquire grid power data corresponding to each inverter in the target power station in real time through NZC, evaluate whether the grid power change corresponding to each inverter in the target power station needs to be fed back, and if the grid power change corresponding to a certain inverter in the target power station needs to be fed back, then the power data of that inverter in the target power station will be transmitted to the grid of that inverter through the established communication link.

[0029] In a specific embodiment, the evaluation process for whether feedback is needed on the grid power change corresponding to each inverter of the target power station is as follows: B1. Analyze the smoothed effective power value corresponding to each inverter of the target power station, and calculate the difference between the smoothed effective power value corresponding to each inverter of the target power station at the current acquisition time and the smoothed effective power value corresponding to each inverter of the target power station at the previous acquisition time, and record the difference as the smoothed effective power value difference.

[0030] B2. If the difference in the smoothed effective power value exceeds the set difference in the smoothed effective power value ±5%, then it is determined whether the grid power change corresponding to the inverter of the target power station needs to be fed back. If the difference in the smoothed effective power value does not exceed the set difference in the smoothed effective power value ±5%, then it is determined that the grid power change corresponding to the inverter of the target power station does not need to be fed back.

[0031] In a specific embodiment, the analysis of the smoothed effective power values ​​corresponding to each inverter in the target power station is carried out as follows: C1. The synchronous sampling module built into the NZC of the target power station synchronously acquires the instantaneous values ​​of the three-phase voltage and three-phase current of the grid corresponding to each inverter in the target power station, and records them as follows: and Substitute into the calculation formula: In this process, the instantaneous power corresponding to each inverter in the target power station is obtained. ,in, This refers to the power factor corresponding to each inverter in the target power station.

[0032] C2. Substitute into the calculation formula: In this process, the smoothed effective power values ​​corresponding to each inverter in the target power station are obtained. ,in, K represents the total number of corresponding data collection times, and K represents the current data collection time. This refers to the time preceding the current data collection time.

[0033] In a specific embodiment, the transmission of power data from the inverter of the target power station to the power grid via the established communication link is as follows: The NZC of the target power station collects the rated power of each inverter in the target power station through built-in current transformers and voltage sensors. When the difference in the smoothed effective power value corresponding to the inverter in the target power station exceeds the set smoothed effective power value difference ±5%, the transmission mechanism is triggered—WiFi communication is sent with UDP multicast packets every 100ms; Sub-1G communication is sent with broadcast frames every 200ms; RS485 communication is sent with Modbus RTU frames every 500ms.

[0034] Power regulation execution module: After each inverter in the target power station receives the grid power data transmitted by NZC, it obtains the rated power parameters corresponding to each inverter in the target power station, and then analyzes the power regulation ratio corresponding to each inverter in the target power station. Based on the power regulation ratio corresponding to the inverter in the target power station, it dynamically analyzes the power regulation value corresponding to the inverter in the target power station.

[0035] In a specific embodiment, the analysis of the power regulation ratio of each inverter in the target power station is carried out as follows: The rated power of each inverter in the target power station is obtained, and the rated power of each inverter in the target power station is accumulated to obtain the total rated power of the target power station. The ratio of the rated power of each inverter in the target power station to the total rated power of the target power station is calculated to obtain the power regulation ratio of each inverter in the target power station, and is denoted as... Where q represents the number corresponding to each inverter. , It is a positive integer. It is also a collection of various inverters.

[0036] In a specific embodiment, the dynamic analysis of the power regulation value corresponding to the inverter of the target power station is carried out as follows: The power regulation ratio corresponding to each inverter of the target power station is calculated according to the formula: Regulation value: The power regulation values ​​corresponding to each inverter in the target power station are obtained, where, The power grid corresponding to the target power station is used to check whether the adjusted power is within the range of 0 to its own rated power. If the adjusted power exceeds the upper limit, the rated power is used; if it is lower than 0, 0 is used. Finally, the adjustment is performed at a rate of ≤5% rated power / second for increasing or ≤10% rated power / second for decreasing, and the actual output power is fed back to NZC to form a closed-loop control.

[0037] In a specific embodiment, the data storage and log management mechanism is as follows: NZC locally stores the grid power and inverter adjustment records for the most recent 3 months at a rate of one record every 5 minutes, with a capacity of ≥100,000 records, and supports export via USB interface; the cloud platform stores all historical data with a retention period of ≥5 years, and allows users to query power curves, adjustment events, and device online status via APP, and automatically generates alarm logs when communication is interrupted or adjustment is abnormal.

[0038] The above description is merely an example and illustration of the concept of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described or use similar methods to replace them, as long as they do not deviate from the concept of the invention or exceed the scope defined in this specification, they should all fall within the protection scope of the present invention.

Claims

1. A backflow prevention control system based on net zero control, characterized in that, include: Communication connection establishment module: used to deploy NZC adapted to multiple scenarios in the target power station. By acquiring the communication environment data of the target power station, it analyzes the corresponding communication method of the target power station and establishes a two-way communication link between the NZC of the target power station and each inverter. Grid Data Monitoring and Transmission Module: Used to acquire grid power data corresponding to each inverter in the target power station in real time through NZC, evaluate whether the grid power change corresponding to each inverter in the target power station needs to be fed back, and if the grid power change corresponding to a certain inverter in the target power station needs to be fed back, then the power data of that inverter in the target power station will be transmitted to the grid of that inverter through the established communication link. The assessment process for determining whether feedback is needed on the grid power changes corresponding to each inverter in the target power plant is as follows: B1. Analyze the smoothed effective power value corresponding to each inverter in the target power station, and calculate the difference between the smoothed effective power value corresponding to each inverter in the target power station at the current acquisition time and the smoothed effective power value corresponding to each inverter in the target power station at the previous acquisition time, and record the difference as the smoothed effective power value difference. B2. If the difference in the smoothed effective power value exceeds the set difference in the smoothed effective power value ±5%, it is determined whether the grid power change corresponding to the inverter of the target power station needs to be fed back. If the difference in the smoothed effective power value does not exceed the set difference in the smoothed effective power value ±5%, it is determined that the grid power change corresponding to the inverter of the target power station does not need to be fed back. The analysis process for the smoothed effective power values ​​corresponding to each inverter in the target power plant is as follows: C1. The synchronous sampling module built into the NZC of the target power station synchronously acquires the instantaneous values ​​of the three-phase voltage and three-phase current corresponding to each inverter of the target power station, and records them as follows: and Substitute into the calculation formula: In this process, the instantaneous power corresponding to each inverter in the target power station is obtained. ,in, The power factor corresponding to each inverter in the target power station; C2. Substitute into the calculation formula: In this process, the smoothed effective power values ​​corresponding to each inverter in the target power station are obtained. ,in, K represents the total number of corresponding data collection times, and K represents the current data collection time. The previous collection time before the current collection time; Power regulation execution module: After each inverter in the target power station receives the grid power data transmitted by NZC, it obtains the rated power parameters corresponding to each inverter in the target power station, and then analyzes the power regulation ratio corresponding to each inverter in the target power station. Based on the power regulation ratio corresponding to the inverter in the target power station, it dynamically analyzes the power regulation value corresponding to the inverter in the target power station.

2. The anti-backflow control system based on net zero control as described in claim 1, characterized in that, The analysis process for the corresponding adaptive communication method of the target power station is as follows: Analyze the communication environment adaptation value corresponding to the target power station, and compare the communication environment adaptation value corresponding to the target power station with the communication environment adaptation value range corresponding to each adaptation communication method in the database. If the communication environment adaptation value corresponding to the target power station is within the communication environment adaptation value range corresponding to a certain adaptation communication method in the database, then record that adaptation communication method in the database as the adaptation communication method corresponding to the target power station. The compatible communication methods include RS485 wired communication, WiFi UDP communication, and Sub-1G wireless communication.

3. The anti-backflow control system based on net zero control as described in claim 2, characterized in that, The analysis process for the communication environment adaptation value corresponding to the target power station is as follows: The communication environment data corresponding to the target power station is obtained. The environment data includes the cabling difficulty coefficient, local area network packet loss rate and equipment distribution density. The data is then normalized and substituted into the communication environment adaptation value analysis model to obtain the communication environment adaptation value corresponding to the target power station.

4. The anti-backflow control system based on net zero control as described in claim 3, characterized in that, The specific process for establishing a bidirectional communication link between the target power station's NZC and each inverter is as follows: A1. If the target power station is compatible with RS485 wired communication, then use shielded twisted pair cable to connect NZC and inverter through terminal block. When wiring, keep a distance of ≥30cm from power lines. Use cold-pressed terminals to crimp the joints and cover them with insulating tubes. Add 120Ω terminating resistors at both ends to ensure stable transmission. A2. If the target power station is adapted to WiFi UDP communication, then connect the NZC and the inverter to the same local area network, enable the UDP multicast function of the NZC, and automatically scan and join the multicast group after the inverter starts up. It will dynamically obtain an IP address through DHCP and maintain a communication delay of ≤100ms. A3. If the target power station is compatible with Sub-1G wireless communication, then configure Sub-1G modules of the same frequency band on the NZC and the inverter. The NZC is set as the master node with a fixed frequency and code rate, and the inverter is set as the slave node to automatically synchronize parameters. The anti-interference capability is enhanced by frequency hopping technology of 10 times per second.

5. The anti-backflow control system based on net zero control as described in claim 1, characterized in that, The process of transmitting power data from the inverter at the target power station to the grid via the established communication link is as follows: The target power station NZC collects the rated power of each inverter in the target power station through built-in current transformers and voltage sensors. When the difference in the smoothed effective power value corresponding to the inverter in the target power station exceeds the set smoothed effective power value difference ±5%, the transmission mechanism is triggered: WiFi communication is sent with UDP multicast packets every 100ms; Sub-1G communication is sent with broadcast frames every 200ms; RS485 communication is sent with Modbus RTU frames every 500ms.

6. The anti-backflow control system based on net zero control as described in claim 5, characterized in that, The analysis process for the power regulation ratio of each inverter in the target power plant is as follows: Obtain the rated power of each inverter in the target power station, sum the rated power of each inverter to obtain the total rated power of the target power station, and calculate the ratio of the rated power of each inverter to the total rated power of the target power station to obtain the power regulation ratio of each inverter in the target power station, and record it as . Where q represents the number corresponding to each inverter. , It is a positive integer. It is also a collection of various inverters.

7. The anti-backflow control system based on net zero control as described in claim 6, characterized in that, The dynamic analysis of the power regulation value corresponding to the inverter in the target power station is carried out in the following specific analysis process: The power regulation percentage corresponding to each inverter in the target power station is calculated using the formula: Adjustment value: The power regulation values ​​corresponding to each inverter in the target power station are obtained, where, The power grid corresponding to the target power station is used to check whether the adjusted power is within the range of 0 to its own rated power. If the adjusted power exceeds the upper limit, the rated power is used; if it is lower than 0, 0 is used. Finally, the adjustment is performed at a rate of ≤5% rated power / second for increasing or ≤10% rated power / second for decreasing, and the actual output power is fed back to NZC to form a closed-loop control.

8. The anti-backflow control system based on net zero control as described in claim 1, characterized in that, It also includes a data storage and log management mechanism. The data storage and log management mechanism is as follows: NZC local storage of grid power and inverter adjustment records for the past 3 months, one record every 5 minutes, with a capacity of ≥100,000 records, and supports export via USB interface; the cloud platform stores all historical data, with a retention period of ≥5 years, and power curves, adjustment events, and device online status can be queried through the APP. When communication is interrupted or adjustment is abnormal, alarm logs are automatically generated.

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