An AGC instruction step size capturing method

Abstract

The present invention relates to the field of automatic generation control, and discloses an AGC command step size capturing method, which includes the dispatching to send an AGC command, transmitting the AGC command to the DCS system of the power plant through the power remote terminal control system RTU. Some power plants use a PLC external system for auxiliary frequency modulation control, and some DCSs require an interface machine to achieve data interaction with the PLC; record the AGC command value corresponding to each sampling time point (t n ) to determine the start and end times of the AGC command. The present invention can automatically locate the start and end times of the AGC command dispatched by the dispatching, intelligently capture the AGC command step size, without manual intervention, and the time monitoring window Δt and the monitoring load command ΔP can be flexibly adjusted. The monitoring values can be set according to the actual transmission situation of the AGC command of the unit and equipment. The present invention also has an alarm for abnormal AGC command data transmission links. According to the delay characteristics of the unit AGC command, an appropriate alarm threshold can be selected to timely withdraw the external device to avoid difficulties in unit load tracking regulation.

Description

Technical Field

[0001] The present invention relates to the technical field of automatic generation control, and specifically to a method for capturing the step size of AGC commands. Background Art

[0002] AGC command: The AGC command is part of Automatic Generation Control, aiming to adjust the output of generating units to meet the frequency and power demands of the power system. The main objectives of the AGC command are to maintain the deviation of the system frequency from the rated value within the allowable range and to maintain the deviation of the net exchange power of the external connection line from the planned value within the allowable range. In practical applications, the AGC command is issued through the dispatching automation system, requiring the generating units to adjust their output according to the command. This process involves real-time monitoring and adjustment of the generating units within the region to ensure real-time balance between power supply and demand. Provincial dispatching automation systems usually have AGC functions. By implementing the AGC command, high-quality power supply can be obtained, real-time balance between power supply and demand can be achieved, and the labor intensity of operation and management personnel can be reduced. Step size: The single adjustment amplitude of the AGC command.

[0003] Under the new situation, the power grid's requirements for the response time (i.e., AGC response rate) of each unit to the AGC command are continuously increasing. Due to the long heat release inertia time of the coal-fired power unit boiler, to increase the unit's load change rate, fuel must be added or subtracted in advance. Monitoring the AGC command step size is the key to predicting the system's power demand and boiler output in advance; in order to meet the requirements of the new frequency modulation documents, each power plant has successively installed frequency modulation external devices to increase the unit's load change rate to obtain frequency modulation auxiliary service mileage compensation. The AGC command has more transmission links and a longer path than before, and signal delay and distortion are likely to occur, which increases the difficulty of capturing the AGC command step size.

[0004] However, currently, several methods for obtaining the dispatching AGC command step size have the following defects: Obtaining by relying on the planned curve: Currently, the common way to obtain the AGC command step size of a unit is based on the daily load planned curve (one set value every 5 minutes or 15 minutes) issued by the power grid dispatching; due to the continuous rapid increase in the grid-connected capacity of new energy and the complex and changeable grid load demand that is difficult to predict, the actual unit output demand often deviates greatly from the planned curve. Calculating the step size by the difference before and after the change of the AGC command: Due to the many transmission links and long path of the AGC command, a single step command of the AGC received by the DCS or external terminal is easily distorted into complex signals such as multiple step commands or ramps. This method is prone to capturing the wrong deformed AGC command step size and reducing the unit's regulation performance. Summary of the Invention

[0005] In view of the deficiencies of the prior art, the present invention provides a method for capturing the AGC command step size, which solves the problem that the existing method is prone to capturing incorrect deformed AGC command step sizes and reducing the regulation performance of the unit.

[0006] To achieve the above objectives, the present invention is realized through the following technical solutions: A method for capturing the AGC command step size, including the following steps:

[0007] S1: The dispatcher sends an AGC command, and the AGC command is transmitted to the DCS system of the power plant through the remote terminal control system RTU of the power grid. Some power plants use a PLC external system for auxiliary frequency modulation control, and some DCSs require an interface machine to interact with the PLC to achieve data interaction;

[0008] S2: Record the AGC command value corresponding to each sampling time point (t n ) to determine the start and end times of the AGC command;

[0009] S3: Set a time monitoring window (Δt), and the minimum change amount of the monitored load command within this time should not be less than the monitored load command (ΔP);

[0010] S4: Use the time monitoring window to mark the start and end times of the AGC command transmission, specifically:

[0011] When , it is determined that the dispatcher's variable load AGC command starts to be received;

[0012] When , it is determined that the reception of the dispatcher's variable load AGC command ends;

[0013] S5: Judge whether the AGC command transmission is normal by comparing the relationship between (t n2 -t n1 ) and the predetermined time (ΔT). If (t n2 -t n1 <ΔT), it indicates that the AGC command is transmitted within the predetermined time and the data transmission link is normal; otherwise, it prompts that the AGC command data transmission link of the external system is abnormal;

[0014] S6: If the data transmission link is normal, calculate the AGC command step size and automatically reset the AGC command step size capture control loop.

[0015] Preferably, the time monitoring window (Δt) and the monitored load command (ΔP) can be flexibly adjusted according to the actual AGC command transmission situation of the equipment to adapt to the AGC command transmission problems in different situations.

[0016] ​Preferably, when the AGC instruction fails to complete data transmission within a predetermined time (ΔT), an AGC instruction data transmission link abnormality alarm is issued to prompt the user to check or exit the plug-in system.

[0017] Preferably, after the AGC instruction step is grasped, the method has a self-locking function, maintaining the current AGC instruction step value until the next grasping condition is triggered, and automatically resetting the control loop after grasping to wait for the next working condition to be met.

[0018] Preferably, the method has the ability to automatically locate and schedule the start and end times of sending AGC instructions and intelligently capture the step length of AGC instructions without manual intervention, thereby improving the efficiency and accuracy of AGC instruction capture.

[0019] Preferably, in said S2, "record each sampling time point (t n ) corresponding to the AGC command value To determine the start and end time of the AGC instruction, the following steps are included:

[0020] S2-1: Get each sampling time point (t n ) of the AGC command value

[0021] S2-2: storing the obtained AGC instruction value in a temporary cache;

[0022] S2-3: Periodically check the data integrity in the temporary cache;

[0023] S2-4: Determine the start time and end time of the AGC instruction based on the data in the temporary buffer.

[0024] Preferably, in said S3, "setting a time monitoring window (Δt), during which the minimum change of the monitoring load instruction should not be less than the monitoring load instruction (ΔP)" specifically includes the following steps:

[0025] S3-1: Determine the duration of the time monitoring window (Δt);

[0026] S3-2: continuously monitor the change of load command within the time monitoring window (Δt);

[0027] S3-3: When the load instruction changes When the alarm signal is triggered;

[0028] S3-4: Record the load instruction change value and its corresponding time point.

[0029] Preferably, in said S4, "using the time monitoring window to mark the transmission start and end time of the AGC instruction" specifically includes the following steps:

[0030] S4-1: Upon receiving the first When the instruction is given, mark this time point as the start time (t n1 );

[0031] S4-2: Continue to monitor the changes in subsequent instructions until they meet The instruction appears, marking this time point as the termination time (t n2 );

[0032] S4-3: Calculate the interval between the start time and the end time (t n2 -t n1 );

[0033] S4-4: According to the interval time (t n2 -t n1 ) Determine whether the AGC instruction transmission is normal.

[0034] Preferably, in said S5, "determine whether the AGC instruction transmission is normal, by comparing (t n2 -t n1 ) and the predetermined time (ΔT)” specifically includes the following steps:

[0035] S5-1: Obtain the value of the predetermined time (ΔT);

[0036] S5-2: Comparison (t n2 -t n1 ) and (ΔT);

[0037] S5-3: If (t n2 -t n1 )<(ΔT), it is determined that the AGC instruction is transmitted within the predetermined time and the data transmission link is normal;

[0038] S5-4 If (t n2 -t n1 )≥(ΔT), it indicates that the AGC instruction data transmission link of the plug-in system is abnormal. Preferably, in the above S6, "if the data transmission link is normal, calculate the AGC instruction step length The specific steps include:

[0039] S6-1: When (t n2 -t n1 )<(ΔT), proceed to the next step;

[0040] S6-2: Calculation

[0041] S6-3: Determine whether the calculated (ΔP) is within a preset range, e.g.

[0042] S6-4: If the condition is satisfied, save (ΔP) to the database and reset the AGC instruction step size capture control loop.

[0043] The present invention provides an AGC instruction step size capture method, which has the following beneficial effects:

[0044] 1. The present invention can automatically locate and schedule the start and end times of sending AGC instructions, intelligently capture the AGC instruction step size, without manual intervention. The time monitoring window Δt and the monitored load instruction ΔP can be flexibly adjusted, and the monitoring values can be set according to the actual transmission situation of the AGC instructions of the unit and equipment. The present invention also has an alarm for abnormal AGC instruction data transmission links. According to the delay characteristics of the unit AGC instructions, an appropriate alarm threshold can be selected to exit the external device in time to avoid difficulties in unit load tracking and adjustment.

[0045] 2. The present invention overcomes the defects of the existing methods by carefully planning a series of processes from the reception, monitoring, and evaluation of AGC scheduling commands to determining their actual influence range. It not only solves the challenges that the AGC instruction signal may be interfered with or distorted during the propagation process, but also improves the ability of thermal power units to respond to grid demands, ensuring more efficient energy allocation under the background of the continuously changing power grid. Brief Description of the Drawings

[0046] Figure 1 It is a schematic diagram of the AGC instruction step size capture method of the present invention;

[0047] Figure 2 It is a schematic logic diagram of the AGC instruction step size capture method of the present invention;

[0048] Figure 3 It is a schematic diagram of an application example of the AGC instruction step size capture of the present invention;

[0049] Figure 4 It is a flowchart of an AGC instruction step size capture method;

[0050] Figure 5 In S2, "record the AGC instruction value corresponding to each sampling time point (t n ) to determine the start and end times of the AGC instruction" flowchart; It is a flowchart of "setting the time monitoring window (Δt), and the minimum change amount of the monitored load instruction within this time should not be less than the monitored load instruction (ΔP)" in S3;

[0051] Figure 6 It is a flowchart of "using the time monitoring window to mark the start and end times of the AGC instruction transmission" in S4;

[0052] Figure 7 It is a flowchart of "using the time monitoring window to mark the start and end times of the AGC instruction transmission" in S4;

[0053] Figure 8 In S5, it is a flowchart of "judging whether the AGC command transmission is normal by comparing the relationship between (t n2 -t n1 ) and the predetermined time (ΔT)".

[0054] Figure 9 In S6, it is a flowchart of "if the data transmission link is normal, then calculating the AGC command step size ". Detailed implementation manners

[0055] To make the objectives, technical solutions and advantages of the embodiments of the present disclosure clearer and more understandable, the embodiments of the present disclosure will be further described in detail below in conjunction with the embodiments and the accompanying drawings. The illustrative embodiments and descriptions thereof of the present disclosure are only used to explain the embodiments of the present disclosure and do not limit the embodiments of the present disclosure.

[0056] Next, referring to the attached Figure 1 - attached Figure 9 , a method for capturing the AGC command step size of the present invention, its specific steps and implementation scenarios are described. This method provides a more accurate and effective solution to the problems such as delay and signal instability existing in the existing methods. Through detailed step descriptions and specific examples, we can understand this process more clearly.

[0057] First, starting from step one, the dispatching center sends AGC (Automatic Generation Control) commands to each generator, and the communication interaction between the remote terminal RTU and the in-plant system is involved in this process. In some power plants, in addition to the traditional distributed control system (DCS), a programmable logic controller (PLC) is introduced as an external enhancement device. These devices usually need to establish a communication bridge with the main control system via the interface machine to ensure that the commands can be interpreted and executed in a timely and correct manner. This initial step ensures the start of the entire automatic generation control cycle.

[0058] Specifically, in the second step, we need to record the changes in the AGC command status within a specific interval. It is mentioned here that the power value information at that time is saved every once in a while for subsequent comparison and analysis. These sampled data provide a basis for detecting the time interval between the start and completion of the actual adjustment task, and further support our evaluation of the overall process efficiency and reliability and the proposal of improvement suggestions.

[0059] Next is how to set an appropriate time window to filter out non-interfering fluctuations and identify the key nodes that truly represent the start and end signs of regulation. The selection of the time window is directly related to the anti-interference performance against minor fluctuations. At the same time, it is also necessary to balance the requirements of rapidity and accuracy in response time to the actual load demand changes. After determining the above two aspects of indicators, the relevant hardware device configuration or software strategy can be adjusted accordingly to achieve the optimized result output, further improving the operation efficiency level of the entire energy supply network and ultimately achieving more refined operation management and more user-friendly service quality.

[0060] Use the set threshold (i.e., the minimum load change within Δt is at least ΔP) to perform a second-order discrimination on the signal: If the measured change exceeds the preset limit within the continuous observation period, it can be announced that the load change operation has started until it is observed again that the value stabilizes (even so, it is still necessary to pay continuous attention to avoid returning to the standby state due to sudden interference midway). This stage can efficiently identify the key time nodes that truly represent the start and complete termination of the instruction.

[0061] Subsequently, there is a verification process for the true availability of the previously obtained data. The specific operation is to compare whether the time difference between the two recording moments falls within the normal expected value. Through comparison, if the difference is less than the preset safe transmission time range, it means that there is no serious delay or loss problem interference during the whole process and it is allowed to proceed to the next step; otherwise, it will remind the administrator that there may be communication quality hidden dangers and it is necessary to find out the reasons and eliminate them before continuing with the remaining work steps, so as to exclude the fault source in the first time and avoid greater losses or adverse consequences.

[0062] If the verification result shows that all communications comply with the specifications, the total electrical output change amount information during the implementation of this adjustment order can be successfully obtained at this time. This value is of great significance for evaluating the response flexibility and stability of each power generation facility and can also point the direction for subsequent optimization of the regulation algorithm or equipment selection.

[0063] In the last step, when it is confirmed that all the conclusions after the previous collection and verification meet the set conditions, a reset program will be started to clear the old monitoring point records. Doing so can not only make space preparations for possible future updates but also help reduce the memory pressure and prevent the situation where it is impossible to restart the calculation after an accidental disconnection.

[0064] For example, assume that a dispatching department located at the center of a certain province issues an emergency call arrangement to several local power stations at a certain moment, requiring them to increase the total output by 10%. Starting from around that moment, the specific differences in the received instructions at each location become the focus of research, especially paying attention to those positions where data may be distorted due to multiple intermediate transmissions. Using the series of automated judgment steps described above, engineers can quickly capture the key turning point information during each independent execution. In this way, even in a very complex actual network situation, it is possible to ensure an accurate and complete overall understanding of the entire process, thus laying a solid foundation for further formulating more reasonable dispatching decisions or taking technical improvement measures for weak links.

[0065] Next, it is described that the time monitoring window (Δt) and the monitoring load instruction of the present invention can be flexibly adjusted according to the actual AGC instruction transmission situation of the device to adapt to the AGC instruction transmission problems in different situations. First, the time monitoring window (Δt) is defined as the time period length used by the system when continuously collecting and processing AGC instructions, usually ranging from 0.1 second to 10 seconds, and the optimal value is 1 second to ensure real-time performance and response speed. The monitoring load instruction (ΔP) represents the change amount of the load instruction detected by the system within this time window, ranging from 0 to 50% of the rated power, and the optimal value is 10%. These two are calculated by the formula ΔP = P(t + Δt) - P(t), where P(t) is the load instruction at time t, and (P(t + Δt)) is the load instruction at time (t + Δt), which is used to quantify the change of the load instruction.

[0066] Next, adjust according to the actual AGC instruction transmission situation of the device. The specific steps include: First, monitor the communication status of the device in real time, such as network delay, packet loss rate, etc.; Second, adjust the size of the time monitoring window (Δt) according to the monitoring results. For example, if the network delay is relatively high, the value of (Δt) can be appropriately increased to reduce the risk of instruction loss. On the contrary, if the network condition is good, (Δt) can be reduced to improve the response speed of the system. Third, dynamically adjust the threshold of the monitoring load instruction (ΔP) according to the amplitude of the load change. For example, when the system detects a large load change, the threshold of (ΔP) can be increased to filter out some small noise interferences and ensure the validity of the signal. Specifically, in an embodiment, if the initial setting is (Δt = 1) second and ΔP = 10, and the network delay increases to more than 20 milliseconds within a certain period of time, in order to ensure the stability of data transmission, (Δt) is adjusted to 2 seconds, and at the same time, in order to filter out noise, (ΔP) is increased to 20%, so as to more effectively capture important load instruction changes and improve the overall performance of the system.

[0067] These steps can effectively address the AGC instruction transmission issues in different scenarios by dynamically adjusting the values of (Δt) and (ΔP), ensuring that the system can still maintain a good operating state in a complex environment. For example, when the power station is located in a remote area with poor communication conditions, the false alarm rate in instruction transmission can be reduced by extending (Δt) and increasing the value of (ΔP), thereby enhancing the reliability and stability of the system.

[0068] Next, a method for issuing an abnormal alarm for the AGC instruction data transmission link and prompting to check or exit the external system when the AGC instruction of the present invention fails to complete data transmission within the predetermined time (ΔT) includes several steps. First, after receiving the AGC (Automatic Generation Control) instruction, calculate the expected completion timestamp and start a timer to monitor the time required for the AGC data packet to be sent and replied; the specific steps include starting the timing (time point t_0), sending the AGC instruction, and ending the timing when receiving the response data. Second, before the response is not received at the moment of ΔT, it is considered that a timeout phenomenon has occurred and the abnormal detection logic is triggered; specifically, set the timeout duration threshold, and if the response is not obtained after exceeding this value, it is considered that a problem has occurred. Finally, when the above timeout situation is detected, the alarm mechanism registered in the system immediately operates and reports to the user or the management program in an appropriate form; this process aims to alert the operator about potential link failure problems and decide whether to automatically disconnect or suggest manual intervention to repair the communication channel according to specific settings.

[0069] For example, in an embodiment, assume that there is a process of adjusting an automatic generation control instruction, and it is necessary to transmit the AGC adjustment amount to a remote device in real time through a network interface to perform corresponding operations. To ensure the efficiency and accuracy of instruction transmission, assume that the optimal value of ΔT is set to 200 ms (considering the time required for the receiving end to complete calculations and network latency in general cases). Once the time limit is exceeded and the command has not been correctly executed or the feedback information has not been returned to the sender in a timely manner, it is determined that this connection has become unstable or even failed. In addition, the system will also display a notice recommending to exit or maintain the external expansion part to prevent further potential data loss risks.

[0070] Next, describe that after the AGC instruction step size of the present invention is captured, the method has a self-locking function to maintain the current AGC instruction step size value until the next capture condition is triggered, and automatically reset the control loop after capture to wait for the next condition to be met.

[0071] The steps include the following parts:

[0072] Grab the AGC command step: When the preset grab conditions are met, the system extracts the current AGC command step value from the current running state. This step ensures that the system can accurately obtain the required AGC command step value at a specific moment.

[0073] Start the self-locking function: Once the AGC instruction step is successfully captured, the system immediately enters the self-locking state. In this state, the system will keep the current AGC instruction step value unchanged and will not accept any new instruction changes. This ensures that the system can maintain a stable state for a period of time and avoids the impact of external interference on system stability.

[0074] Maintain AGC command step: In the self-locking state, the system will continue to maintain the captured AGC command step value. No matter how the external environment or system internal parameters change, the system will lock at the current command step value to ensure the stability and reliability of the system.

[0075] Monitoring grasping conditions: The system continuously monitors and evaluates the possibility of triggering grasping conditions again. When it detects that new grasping conditions are met, the system prepares to perform the next grasping action.

[0076] Automatic reset control loop: When the new conditions are met, the system will automatically release the self-locking state and reset the control loop. The reset system is ready for the next grasping operation and continues to execute the same process.

[0077] For example, in the AGC control of the power system, suppose that the system load changes greatly at a certain moment, causing the AGC controller to adjust the output power of the generator. The system determines that the AGC instruction step needs to be updated by monitoring the grid frequency and load changes. At this moment, the system successfully captures the current AGC instruction step value, and then immediately starts the self-locking function to fix this value to avoid other temporary interference. While the system is in the self-locking state, even if other parameters change, the system still maintains this fixed instruction step value. When the grid returns to stability or new load changes occur again, the system detects that the new capture conditions are met, and automatically resets the control loop to prepare for the next capture operation.

[0078] Specifically, assuming that the calculation formula for the AGC instruction step length is (ΔP = K f ·(f-f0)+K L ·(P L -P L0 )) Where (ΔP) represents the AGC command step size, (K f ) is the frequency sensitivity coefficient, (f) is the actual frequency, (f0) is the reference frequency, (K L ) is the load variation coefficient, (P L ) is the actual load, (P L0) is the reference load. The ranges and optimal values of these parameters are usually determined by the actual application and system design. For example, the frequency sensitivity coefficient (K f ) may be set between 0.1 and 0.5, and the optimal value may be 0.3; the load change coefficient (K L ) may be set between 0.5 and 1.5, and the optimal value may be 1.0. This setting is to ensure that the AGC controller can respond quickly and maintain the stable operation of the system when responding to frequency and load changes.

[0079] The meaning of this formula is that by combining the frequency deviation and load deviation, the AGC command step size is dynamically adjusted to ensure that the system can maintain stable and efficient operation under different working conditions. Setting the formula in this way can effectively cope with the actual changes in the power grid and provide more flexible and accurate control.

[0080] Next, it is described that the method of the present invention has the ability to automatically locate the start and end times of dispatching and sending AGC commands and intelligently capture the AGC command step size, without manual intervention, improving the efficiency and accuracy of AGC command capture.

[0081] First, the method automatically identifies and extracts the data segment of the AGC command from the received data stream. The key to this step is to use predefined rules or algorithms to filter and match specific data formats or protocol fields that may contain AGC commands. For example, by parsing the communication protocols of the power system, such as Modbus or DNP3, to find the messages related to the AGC command.

[0082] Secondly, the method determines the specific start and end times of the command transmission by analyzing the identified AGC command data segment. This process usually involves the processing and comparison of timestamps. The specific implementation method can be to compare multiple timestamps to find the start and end time points of the AGC command in the data stream. For example, in a series of received messages, the timestamp of the first message containing the AGC command identifier is determined as the start point of the command transmission, and the timestamp of the last message carrying the command is marked as the end point of the command transmission.

[0083] Then, the method intelligently captures the step size information in the AGC command. This step involves in-depth parsing of the AGC command content to extract the key parameters. Specifically, pattern recognition algorithms or rule engines can be used to identify the step size field and extract it. For example, if the AGC command is sent in binary form, the parsing algorithm will extract the step size value from the data stream according to the preset byte position or displacement.

[0084] In addition, to improve accuracy, the method also includes a verification step for the extraction results. This means that through multiple crawls and comparisons, the consistency and reliability of the extracted start and end times and step size information are ensured. For example, in one embodiment, the system will extract the AGC instructions received within multiple time periods multiple times and calculate their average value or mode value to reduce errors and improve accuracy.

[0085] Finally, all the above steps are automatically completed without manual intervention, ensuring the efficiency and automation of instruction crawling. For example, the system can automatically generate reports during the entire process of receiving data, showing the start and end times and step size information of each instruction for the operator's reference.

[0086] To further optimize the performance of the method, the following formula can be used to evaluate the effectiveness of the steps:

[0087]

[0088] where represents the actual start and end time of the (i)-th time, represents the predicted start and end time of the (i)-th time, and (n) is the number of test times. This formula is used to calculate the mean square error (MSE) between the actual and predicted times. The smaller the (E) value, the higher the accuracy. In the optimal case, this value should approach zero. By minimizing (E), the system can better adjust and optimize parameters to improve the accuracy and efficiency of instruction crawling.

[0089] Next, in the S2 of the present invention described, recording the AGC instruction value corresponding to each sampling time point (t n ) to determine the start and end time of the AGC instruction specifically includes the following steps: To determine the start and end time of the AGC instruction specifically includes the following steps:

[0090] S2-1: Obtain the AGC instruction value at each sampling time point (t n ) This step means that at a specific sampling time point (t n ), the system reads the current AGC instruction value from the automatic generation control system (AGC). The sampling time point is usually determined by the preset time interval of the system, such as once per second or once every five minutes. For example, in a specific embodiment, data is collected once per minute. When the time point t1 is 00:00:00, the AGC instruction value read by the system may be 120 kW.

[0091] S2-2: Store the obtained AGC instruction value in a temporary cache; this step refers to storing each AGC instruction value read from the AGC system Stored in a temporary data cache. This temporary cache is usually a block of space in memory for short-term data storage for quick access and processing. Specifically, when the system obtains at t1, it will immediately store it in the temporary cache. If at t2, the system obtains again, it will also be stored in the temporary cache.

[0092] S2-3: Regularly check the data integrity in the temporary cache; This step refers to regularly checking the data in the temporary cache to ensure that all necessary data has been correctly stored and not lost. The check is usually done by calculating the timestamps of each data packet to verify continuity. For example, check the data integrity in the temporary cache every 10 seconds. If a missing data is found between t3 and t4, trigger the corresponding error handling mechanism.

[0093] S2-4: Determine the start time and end time of the AGC instruction based on the data in the temporary cache; This step is to use the AGC instruction values stored in the temporary cache to determine the start time and end time of the AGC instruction. Specifically, when a significant change in the AGC instruction value is detected, the system will record the time points before and after the change, and these time points are the start time and end time of the AGC instruction. For example, assume that the AGC instruction value changes from 120kW to 150kW at t5, then t5 is recorded as the start time of the new AGC instruction; when at t 10 , the AGC instruction value returns from 150kW to 120kW again, then t 10 is recorded as the end time of this AGC instruction.

[0094] The parameter (t n ) represents the nth sampling time point, represents the AGC instruction value at the time point (t n ). The ranges of these two parameters are: (t n ) is a non-negative real number, representing the time point since the start time; usually varies between 0kW and the maximum output power of the power station. The specific range depends on the installed capacity of the power station. The optimal setting is usually to select an appropriate sampling frequency and data verification period on the premise of ensuring real-time performance and accuracy to avoid increasing the system burden due to frequent sampling or verification. The formula is for accurately recording the real-time instruction value of the AGC system for subsequent analysis and control. Setting this formula is to ensure that the changes in the system instructions can be captured and responded to in a timely manner.

[0095] Next, in step S3 of the present invention, a time monitoring window (Δt) is set, and the minimum change amount of the load instruction monitored within this time should not be less than the monitored load instruction (ΔP), which specifically includes the following steps:

[0096] S3-1: Determine the duration of the time monitoring window (Δt); this step involves determining the time interval during which the load instruction needs to be continuously monitored. The setting of (Δt) is usually based on the response time of the system and actual requirements. For example, if the response time of the system is short, then (Δt) can be set to a few seconds; if the response time of the system is long, then (Δt) can be set to a few minutes. The optimal value of (Δt) depends on the specific situation of the system, and it is generally recommended to obtain the best value from actual operation data. Specifically, assume that in a power system, the response time of the AGC (Automatic Generation Control) system is about 5 seconds, so (Δt) can be set to 5 seconds.

[0097] S3-2: Continuously monitor the change of the load instruction within the time monitoring window (Δt); in this step, the system will continuously collect the change data of the load instruction during this period to ensure that any change can be detected in a timely manner. For example, when (Δt) is set to 5 seconds, the system will collect the data of the load instruction once per second and record it. This process can be achieved through a timing task or an interrupt mechanism to ensure the accuracy and real-time nature of the data. In one embodiment, assume that the system collects the load instruction data once per second, and a total of 5 data points are collected within 5 seconds.

[0098] S3-3: When the change value of the load instruction , trigger an alarm signal; the purpose of this step is to issue an alarm when the change of the load instruction exceeds the preset threshold. Here, represents the load instruction value at the start of monitoring, represents the load instruction value after time (Δt), and (ΔP) is the set minimum change amount threshold. For example, assume after 5 seconds If the set (ΔP = 40) MW, then because the change value is 50 MW, which exceeds the threshold, an alarm signal is triggered. The design of this step aims to promptly detect abnormal changes in the load instruction and ensure that the system can respond quickly.

[0099] S3-4: Record the change value of the load command and its corresponding time point; when the detected change value of the load command exceeds (ΔP), the system will record this change value and the specific time point when it occurs. For example, the recorded data may include: change value 50MW, time point is 15:30:05 on October 16, 2024. This record is used for subsequent analysis and auditing, helping the operation and maintenance personnel understand the change situation of the load command, and then optimizing the operation strategy of the system. Specifically, assume that at 15:30:05 on October 16, 2024, the system records the change event that the load command increases from 800MW to 850MW.

[0100] Through the above steps, this method can effectively monitor and record the change situation of the load command, providing strong support for the safe and stable operation of the power system.

[0101] Next, in S4 of the present invention, the specific steps of marking the start and end times of the AGC command transmission using the time monitoring window are as follows:

[0102] When receiving the first qualified command, mark this time point as the start time (t_{n1}). Here, P_{t_{n1}} represents the power value at time t_{n1}, Δt is a fixed time delay constant representing the time difference from the command being sent to received, and ΔP is a preset threshold used to determine whether the command has changed. When the absolute value of the power change is greater than ΔP, it indicates that the start stage of the AGC command has begun. The range of the parameter Δt is usually between a few milliseconds and dozens of milliseconds, and the optimal value depends on the response speed of the system. For example, in one embodiment, if at time t n1 = 10:00:01, the monitored power change |150 + 0.01 - 150| = 0.01 > 0.005MW, then time t n1 will be marked as the start time.

[0103] Continue to monitor the changes of subsequent commands until a qualified command appears, and mark this time point as the end time (t n2 ). Here, represents the power value at time t n2 . In the formula, actually means that after time t n2 , after a time delay of Δt, the absolute value of the power change is less than the threshold ΔP, which means that the AGC command has ended. The parameter ΔP is still the previously set threshold. For example, in the above example, if at time t n2 = 10:00:10, the monitored power change |152 - 152 - 0.01| = 0.01 < 0.005MW, then time tn2 The end time will be marked.

[0104] Calculate the interval between the start time and the end time (t n2 -t n1 ). This interval represents the duration of the entire AGC command transmission. Continuing with the above example, if t n1 =10:00:01 and t n2 =10:00:10, then the interval t n2 -t n1 =9 seconds.

[0105] According to the interval time (t n2 -t n1 ) Determine whether the AGC command transmission is normal. Usually a reasonable interval time range is set. If the actual interval time is within this range, the AGC command transmission is considered normal. Otherwise, there may be a problem in the transmission process and further inspection is required. Specifically, assuming that the calculated interval time is 9 seconds and the reasonable time range is 7 to 12 seconds, it can be determined that the AGC command transmission is normal.

[0106] The above steps ensure accurate monitoring of the AGC command transmission process, which helps to improve the operating efficiency and reliability of the system.

[0107] Next, the S5 of the present invention is described, judging whether the AGC instruction transmission is normal, by comparing (t n2 -t n1 ) and the predetermined time (ΔT) specifically include the following steps:

[0108] S5-1: Obtain the value of the predetermined time (ΔT);

[0109] S5-2: Comparison (t n2 -t n1 ) and (ΔT);

[0110] S5-3: If (t n2 -t n1 )<(ΔT), it is determined that the AGC instruction is transmitted within the predetermined time and the data transmission link is normal;

[0111] S5-4 If (t n2 -t n1 )≥(ΔT), it indicates that the AGC command data transmission link of the plug-in system is abnormal.

[0112] S5-1: Obtain the value of the predetermined time (ΔT). This step aims to obtain the time threshold (ΔT) preset by the system from a configuration file or other predefined sources. This threshold is used to evaluate the time efficiency of AGC instruction transmission. The value of the predetermined time (ΔT) can vary according to the requirements of the actual application, usually at the millisecond level, such as 500 milliseconds or 1000 milliseconds. The optimal value is usually the result of comprehensive consideration of the real-time performance and stability of the system.

[0113] S5-2: Compare (t n2 -t n1 ) with (ΔT). In this step, the system calculates the actual time difference (t n2 -t n1 ) from the sending to the receiving of the AGC instruction and compares it with the predetermined time (ΔT). t n1 ) represents the sending time of the AGC instruction, and (t n2 ) represents the receiving time of the AGC instruction. The purpose of this formula is to quantify the time delay of instruction transmission in order to evaluate the performance of the data link. The meaning of the formula (t n2 -t n1 ) is to measure the specific time taken from the instruction being sent to being received, so as to determine whether the transmission is completed within the predetermined time.

[0114] S5-3: If (t n2 -t n1 ) < (ΔT), it is determined that the AGC instruction is transmitted within the predetermined time and the data transmission link is normal. When the actual transmission time (t n2 -t n1 ) is less than the predetermined time (ΔT), it indicates that there are no obvious problems with the data link, the instruction transmission is efficient, and it can be considered that the system is operating normally. For example, in an embodiment, assume that (ΔT) is set to 500 milliseconds, and (t n2 -t n1 ) is measured to be 300 milliseconds, then the system will determine that the AGC instruction transmission is completed within the specified time and the link is normal.

[0115] S5-4: If (t n2 -t n1 ) ≥ (ΔT), it is prompted that the data transmission link of the external system's AGC instruction is abnormal. When the actual transmission time (t n2 -t n1 ) is equal to or greater than the predetermined time (ΔT), the system will trigger an abnormal alarm, prompting the external system to pay attention to possible problems with the data link and further inspection and processing are required. For example, assume that (ΔT) is set to 500 milliseconds, and (t n2 -t n1) If the measured value is 600 milliseconds, the system will determine that the transmission of this AGC instruction has exceeded the predetermined time, and there may be a problem with the link. The operator should be reminded to check the network status or the bottleneck in the data processing process.

[0116] The above four steps together constitute the judgment logic for whether the AGC instruction transmission is normal. In this way, the stability and transmission efficiency of the data link can be effectively monitored to ensure the efficient and reliable operation of the power system.

[0117] Next, in S6 of the present invention, if the data transmission link is normal, the AGC instruction step size is calculated Specifically, it includes the following steps:

[0118] S6-1: When (t n2 -t n1 ) < (ΔT), continue to the next step;

[0119] S6-2: Calculate

[0120] S6-3: Determine whether the calculated (ΔP) is within the preset range, for example

[0121] S6-4: If the condition is met, save (ΔP) to the database and reset the AGC instruction step size capture control loop.

[0122] In step S6-1, first, it is necessary to determine whether the difference (t n2 -t n1 ) between two time points is less than the predetermined time interval (ΔT). (t n2 ) represents the moment when the AGC instruction is read for the second time, and (t n1 ) represents the moment when it is read for the first time. (ΔT) is a preset time threshold, usually set to the time of several sampling periods, to ensure that the time difference between two reads is within a reasonable range to accurately capture the change of the AGC instruction. For example, if (ΔT) is set to 10 seconds and (t n2 -t n1 ) is equal to 5 seconds and this condition is met, then continue to the next step.

[0123] In step S6-2, according to the result of the previous step, calculate the AGC instruction step size Here and respectively represent at the moment (t n2 ) and at the moment (t n1) the AGC command value at that time. By calculating the difference between these two values, the change amount of the AGC command during this period is obtained. The core of this step is to quantify the change amplitude of the AGC command and provide basic data for further analysis and processing.

[0124] In step S6-3, it is judged whether the calculated (ΔP) is within a preset reasonable range. Specifically, it is necessary to verify whether the absolute value |ΔP| is greater than The coefficient 10.1 in the formula is an empirical value determined after multiple experiments and verifications, and is used to judge whether the change of the AGC command significantly exceeds the expected range. Indicates the average value of the AGC command value between (t n1 ) and (t n2 ). By comparing the change amount (ΔP) with this average value, noise and other unexpected changes can be effectively filtered out. If the calculated |ΔP| is indeed greater than the preset range, this change is considered valid, otherwise it is considered noise or an invalid change.

[0125] Finally, in step S6-4, if the judgment condition in step S6-3 is satisfied, the calculated (ΔP) is saved to the database, and the AGC command step capture control loop is reset. The purpose of this step is to record important change events and reset the system to prepare for the next detection. By resetting the control loop, the stability and accuracy of the system are ensured. For example, in an embodiment, if the detected (ΔP) is 500 MW and the preset range is 150 MW (based on the coefficient of 10.1 and the average value of the AGC command), then 500 MW is greater than 150 MW, which meets the condition. Therefore, (ΔP) will be saved and the control loop will be reset to prepare for the next detection.

[0126] The above steps describe in detail the specific process of calculating and processing the AGC command step when the data transmission link is normal. Through these steps, the command changes in the power system can be effectively captured and managed.

[0127] An AGC command step capture method of the present invention includes: the AGC command issued by the dispatching agency is conveyed to the DCS (Distributed Control System) at the power plant end by the RTU (Remote Terminal Control System) through power remote control. Considering the configuration differences of digital systems in different power plants, some may also additionally integrate a PLC (Programmable Logic Controller) system for auxiliary frequency modulation control, and data exchange with the PLC needs to be implemented through an interface. In order to solve the problem of command distortion caused by a complex signal transmission network, especially to improve the rapid response ability and accuracy of the unit under automatic generation control, this step not only strengthens the tracking accuracy of load changes, but also ensures the rapid and effective response of the system to AGC command changes (step S1).

[0128] Next, record the actual load value corresponding to the AGC operation at each specific time (t n ) within this period In this way, the specific time period when the AGC dispatching command starts and ends is determined (step S2). Then, a monitoring period (Δt) is set to monitor the minimum change in the load command during this period. This method helps to confirm valid load change signals rather than noise or temporary fluctuations (steps S3) and (S4).

[0129] By defining the method of receiving and stopping receiving the specific time points of the dispatching center's changed load command (S4), the time periods of these key stages can be marked more accurately, and further verify whether there are abnormalities in the data transmission process, such as delays or losses, etc., by comparing the predetermined delay with the actual situation (step S5).

[0130] If no abnormality is confirmed, then perform subsequent operations to calculate the AGC step value This value reflects the change range of the generator output power during a dispatching order process. Once this step value is obtained, the AGC capture program will be immediately re-initialized to continuously provide the latest dynamic information of the AGC command and promptly respond to the system's demand for rapid and stable power regulation (step S6).

[0131] Generally speaking, the present invention overcomes the defects of the existing methods by carefully planning a series of processes from the acceptance, monitoring, and evaluation of the AGC dispatching command to determining its actual influence range. It not only solves the challenges that the AGC command signal may be interfered with or distorted during the propagation process, but also improves the ability of thermal power units to respond to grid demands, ensuring better efficiency of energy allocation in the context of the constantly changing power grid. This is not only an effective innovation of traditional means, but also particularly valuable and practical in the current increasingly complex and constantly changing energy management system. Such a more refined and reliable AGC step width capture method can support the identification and response to demand changes with higher efficiency and accuracy, thereby enhancing the flexibility and security of the entire network operation.

[0132] The specific embodiments described above further elaborate on the purpose, technical solutions, and beneficial effects of the embodiments of the present disclosure. It should be understood that the above description is only the specific embodiments of the embodiments of the present disclosure and is not used to limit the protection scope of the embodiments of the present disclosure. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the embodiments of the present disclosure shall be included in the protection scope of the embodiments of the present disclosure.

Claims

1. A method for capturing the step length of an AGC instruction, characterized in that: The following steps are involved: S1: The dispatcher sends the AGC command, which is transmitted to the DCS system of the power plant through the power remote terminal control system RTU. Some power plants use PLC plug-in systems for auxiliary frequency regulation control, and some DCS require an interface machine to realize data interaction with PLC; S2: Record each sampling time point (t n ) corresponding to the AGC command value To determine the start and end time of the AGC instruction; S3: Set the time monitoring window (Δt), during which the minimum change of the monitoring load command should not be less than the monitoring load command (ΔP); S4: Use the time monitoring window to mark the transmission start and end time of the AGC instruction, specifically: when When , it is determined that the dispatching variable load AGC instruction starts to be received; when When , it is determined that the receiving of the dispatching variable load AGC instruction is completed; S5: Determine whether the AGC instruction transmission is normal by comparing (t n2 -t n1 ) and the predetermined time (ΔT), if (t n2 -t n1 <ΔT), it indicates that the AGC instruction is transmitted within the scheduled time and the data transmission link is normal; otherwise, it indicates that the AGC instruction data transmission link of the plug-in system is abnormal; S6: If the data transmission link is normal, calculate the AGC instruction step length And automatically reset the AGC instruction step capture control loop.

2. The AGC instruction step length capture method according to claim 1, characterized in that: The time monitoring window (Δt) and the monitoring load instruction (ΔP) can be flexibly adjusted according to the actual AGC instruction transmission situation of the equipment to adapt to the AGC instruction transmission problems in different situations.

3. The AGC instruction step length capture method according to claim 1, characterized in that: When the AGC instruction fails to complete data transmission within the predetermined time (ΔT), an AGC instruction data transmission link abnormality alarm is issued, prompting the user to check or exit the plug-in system.

4. The AGC instruction step length capture method according to claim 1, characterized in that: After the AGC instruction step is grasped, the method has a self-locking function, maintaining the current AGC instruction step value until the next grasping condition is triggered, and automatically resetting the control loop after grasping to wait for the next working condition to be met.

5. A method for capturing the AGC instruction step length according to any one of claims 1 to 4, characterized in that: The method has the ability to automatically locate and schedule the start and end times of sending AGC instructions and intelligently capture the step length of AGC instructions without manual intervention, thereby improving the efficiency and accuracy of AGC instruction capture.

6. The AGC instruction step length capture method according to claim 1, characterized in that: In the S2, "record each sampling time point (t n ) corresponding to the AGC command value To determine the start and end time of the AGC instruction, the following steps are included: S2-1: Get each sampling time point (t n ) of the AGC command value S2-2: storing the obtained AGC instruction value in a temporary cache; S2-3: Periodically check the data integrity in the temporary cache; S2-4: Determine the start time and end time of the AGC instruction based on the data in the temporary buffer.

7. The AGC instruction step length capture method according to claim 1, characterized in that: In the above S3, "setting a time monitoring window (Δt), during which the minimum change of the monitoring load instruction should not be less than the monitoring load instruction (ΔP)" specifically includes the following steps: S3-1: Determine the duration of the time monitoring window (Δt); S3-2: continuously monitor the change of load command within the time monitoring window (Δt); S3-3: When the load instruction changes When the alarm signal is triggered; S3-4: Record the load instruction change value and its corresponding time point.

8. The AGC instruction step length capture method according to claim 1, characterized in that: In the above S4, "marking the transmission start and end time of the AGC instruction by using the time monitoring window" specifically includes the following steps: S4-1: Upon receiving the first When the instruction is given, mark this time point as the start time (t n1 ); S4-2: Continue to monitor the changes in subsequent instructions until they meet The instruction appears, marking this time point as the termination time (t n2 ); S4-3: Calculate the interval between the start time and the end time (t n2 -t n1 ); S4-4: According to the interval time (t n2 -t n1 ) Determine whether the AGC instruction transmission is normal.

9. The AGC instruction step length capture method according to claim 1, characterized in that: In the above S5, "determine whether the AGC instruction transmission is normal, by comparing (t n2 -t n1 ) and the predetermined time (ΔT)” specifically includes the following steps: S5-1: Obtain the value of the predetermined time (ΔT); S5-2: Comparison (t n2 -t n1 ) and (ΔT); S5-3: If (t n2 -t n1 )<(ΔT), it is determined that the AGC instruction is transmitted within the predetermined time and the data transmission link is normal; S5-4 If (t n2 -t n1 )≥(ΔT), it indicates that the AGC command data transmission link of the plug-in system is abnormal.

10. The AGC instruction step length capture method according to claim 1, characterized in that: In the above S6, "if the data transmission link is normal, then calculate the AGC instruction step length The specific steps include: S6-1: When (t n2 -t n1 )<(ΔT), proceed to the next step; S6-2: Calculation S6-3: Determine whether the calculated (ΔP) is within a preset range, e.g. S6-4: If the conditions are met, save (ΔP) to the database and reset the AGC instruction step capture control loop.

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