Method, system and equipment for flexibly controlling power flow of power grid based on direct current technology

Abstract

The invention discloses a power grid power flow flexible control method, system and equipment based on a direct current technology, and the method comprises the steps: firstly, calculating the power flow data of each direct current transmission line in real time, and generating a standardized direct current power flow real-time data set; then calculating an adjustment power difference value of each line based on the direct current power flow real-time data set, and screening an overrun line based on the adjustment power difference value; and finally, calculating an adjustment voltage deviation value of each over-limit line, and generating a power grid power flow flexible control instruction. Aiming at the problem of non-uniform power distribution of a power grid under an extra-high voltage main transformer, multi-source data are integrated in real time to construct a dynamic monitoring system, an abnormal section is quickly positioned, voltage stability and power transmission requirements are synchronously balanced, the risk of oscillation adjustment is reduced, cross-regional power coordination efficiency is improved, and the disturbance rejection capability under new energy fluctuation is enhanced; dynamic stability and transmission reliability of a power grid are guaranteed.

Description

Technical Field

[0001] This invention belongs to the field of smart grids, specifically relating to a flexible power flow control method, system, and device for power grids based on DC technology. Background Technology

[0002] The field of smart grid technology encompasses two aspects: power transmission network operation and control, and multi-regional grid interconnection. Its core is achieving dynamic power balance in the grid through high-voltage direct current (HVDC) transmission, flexible alternating current (AC) transmission, and distributed energy integration. It covers technologies such as hybrid AC / DC networking, multi-voltage level coordinated control, and grid topology reconfiguration. Employing converter station coordinated control strategies, grid equivalent impedance regulation, and hierarchical and regional management mechanisms, it focuses on solving problems related to cross-regional power distribution, renewable energy integration, and system stability, achieving precise power flow allocation and rapid response in interconnected grids. Among these, DC-based grid power flow control utilizes back-to-back DC interconnection projects to regulate power transmission between regional grids.

[0003] Existing power flow control methods based on DC technology include establishing power coupling models between multi-terminal DC networks and AC grids. These models focus on steady-state analysis, neglecting dynamic impedance and real-time operating data, causing regulation commands to deviate from actual needs. They also include setting up joint regulation mechanisms for converter station firing angles and modulation ratios. These mechanisms analyze firing angles in isolation, easily leading to overshoot or undershoot. Furthermore, they involve configuring inter-regional power transmission limit parameter tables. These configuration methods rely on periodic data acquisition and fixed threshold judgments, making it difficult to capture instantaneous power flow anomalies in real time, resulting in identification lag. Finally, they employ DC voltage droop control strategies to coordinate the operating states of multiple converter stations. However, DC voltage droop control uses a uniform coefficient, failing to adapt to differences in section loads, thus limiting the collaborative efficiency of multiple converter stations. Therefore, a new power flow control method based on DC technology is needed to better address the problem of uneven power distribution in the grid under UHV main transformers. Summary of the Invention

[0004] The purpose of this invention is to address the aforementioned problems in the existing technology by providing a flexible power flow control method, system, and device based on DC technology for power grids.

[0005] To achieve the above objectives, the technical solution of the present invention is as follows:

[0006] In a first aspect, the present invention proposes a flexible power flow control method for power grids based on DC technology, comprising:

[0007] S1. Calculate the power flow data of each DC transmission line in real time and generate a standardized real-time DC power flow dataset;

[0008] S2. Based on the real-time DC power flow dataset, calculate the adjustment power difference of each line, and filter out lines exceeding the limit based on the adjustment power difference;

[0009] S3. Calculate the adjustment voltage deviation of each over-limit line and generate flexible power flow control commands.

[0010] S3 includes:

[0011] S31. Read the current trigger angle of the converter station corresponding to the over-limit line, and determine whether the current trigger angle exceeds the preset adjustment range of the trigger angle. If it does not exceed the range, generate a status flag "1"; if it exceeds the range, generate a status flag "0".

[0012] S32. Calculate the adjustment voltage deviation of each over-limit line with the status mark "1";

[0013] S33. Compare the adjusted voltage deviation of each over-limit line with the preset voltage deviation threshold. Perform an absolute value comparison, if If , then the adjustment demand index "0" is generated; if Then, the adjustment demand index "1" is generated, where For the first Adjustment voltage deviation of the over-limit line;

[0014] S34. Calculate the firing angle adjustment range for each over-limit line with an adjustment demand index of "1", and determine whether the voltage difference of the over-limit line is less than 0. If so, mark the adjustment direction "+" and increase the firing angle; if not, mark the adjustment direction "-" and decrease the firing angle.

[0015] S35. Based on the trigger angle adjustment range and adjustment direction of each over-limit line, generate flexible power flow control commands.

[0016] In step S32, the adjustment voltage deviation of each over-limit line marked with "1" is calculated using the following formula:

[0017] ;

[0018] ;

[0019] In the above formula, For the first Adjustment voltage deviation of the over-limit line. For the first The voltage difference of the over-limit line, i.e., the first The absolute difference between the current voltage value and the target voltage setting value of the corresponding high-voltage direct transmission line for each over-limit line. For the first The reference voltage value of the over-limit line. For smoothing coefficients, For the first The regulation efficiency coefficient of the over-limit line, This is the baseline value for the system's maximum regulating efficiency. For the first The arc extinguishing angle value of the over-limit line, The optimal arc-extinguishing angle reference value for the system. For the first The difference between the current control setpoint and the rated value of the over-limit circuit. For the first The trigger angle value of the over-limit line, , , These are the median, maximum, and minimum values ​​of the preset adjustment range for the trigger angle, respectively.

[0020] In S34, the firing angle adjustment range of each over-limit line with an adjustment demand index of "1" is calculated using the following formula:

[0021] ;

[0022] In the above formula, For the first The trigger angle adjustment range of the over-limit circuit.

[0023] S2 includes:

[0024] S21. Calculate the adjustment power difference for each line using the following formula, by retrieving the continuous periodic power flow from the real-time DC power flow dataset for each line:

[0025] ;

[0026] ;

[0027] In the above formula, For the line Adjust the power difference. For the line The power flow cycle difference, The periodic time constant, For the line The reference power value, To prevent division by zero of extremely small constants, For the line No. Power value per cycle, For the line No. Power value per cycle;

[0028] S22. Compare the adjusted power difference of each line with the preset power change threshold. Perform an absolute value comparison, if If so, the power fluctuation of the line is within the normal allowable range; if If so, the line is marked as an over-limit line.

[0029] Secondly, this invention proposes a flexible power flow control system for power grids based on DC technology, including a real-time dataset generation module, an over-limit line screening module, and a flexible control command generation module.

[0030] The real-time dataset generation module is used to calculate the power flow data of each DC transmission line in real time and generate a standardized real-time DC power flow dataset.

[0031] The over-limit line screening module is used to calculate the adjustment power difference of each line based on the real-time DC power flow dataset, and to screen over-limit lines based on the adjustment power difference.

[0032] The flexible control command generation module is used to calculate the adjustment voltage deviation of each over-limit line and generate flexible power flow control commands.

[0033] The flexible control command generation module includes a status flag generation unit, an adjustment voltage deviation calculation unit, an adjustment demand index generation unit, a trigger angle adjustment amplitude calculation unit, and a power grid flow flexible control command generation unit.

[0034] The status flag generation unit is used to read the current trigger angle of the converter station corresponding to the over-limit line, and determine whether the current trigger angle exceeds the preset adjustment range of the trigger angle. If it does not exceed the range, a status flag "1" is generated; if it exceeds the range, a status flag "0" is generated.

[0035] The voltage deviation calculation unit is used to calculate the voltage deviation of each over-limit line with a status mark of "1".

[0036] The adjustment demand index generation unit is used to compare the adjustment voltage deviation of each over-limit line with a preset voltage deviation threshold. Perform an absolute value comparison, if If , then the adjustment demand index "0" is generated; if Then, the adjustment demand index "1" is generated, where For the first Adjustment voltage deviation of the over-limit line;

[0037] The trigger angle adjustment range calculation unit is used to calculate the trigger angle adjustment range of each over-limit line with an adjustment demand index of "1", and to determine whether the voltage difference of the over-limit line is less than 0. If it is, the adjustment direction mark is "+", and the trigger angle needs to be increased; if it is not, the adjustment direction mark is "-", and the trigger angle needs to be decreased.

[0038] The power grid flow flexible control command generation unit is used to generate power grid flow flexible control commands based on the trigger angle adjustment amplitude and adjustment direction of each over-limit line.

[0039] In the voltage deviation calculation unit, the voltage deviation of each over-limit line marked with "1" is calculated using the following formula:

[0040] ;

[0041] ;

[0042] In the above formula, For the first Adjustment voltage deviation of the over-limit line. For the first The voltage difference of the over-limit line, i.e., the first The absolute difference between the current voltage value and the target voltage setting value of the corresponding high-voltage direct transmission line for each over-limit line. For the first The reference voltage value of the over-limit line. For smoothing coefficients, For the first The regulation efficiency coefficient of the over-limit line, This is the baseline value for the system's maximum regulating efficiency. For the first The arc extinguishing angle value of the over-limit line, The optimal arc-extinguishing angle reference value for the system. For the first The difference between the current control setpoint and the rated value of the over-limit circuit. For the first The trigger angle value of the over-limit line, , , These are the median, maximum, and minimum values ​​of the preset adjustment range for the trigger angle, respectively.

[0043] In the trigger angle adjustment range calculation unit, the trigger angle adjustment range of each over-limit line with an adjustment demand index of "1" is calculated using the following formula:

[0044] ;

[0045] In the above formula, For the first The trigger angle adjustment range of the over-limit circuit.

[0046] The over-limit line screening module includes an adjustment power difference calculation unit and an over-limit line marking unit;

[0047] The adjusted power difference calculation unit is used to call the continuous periodic power flow of each line in the real-time DC power flow dataset and calculate the adjusted power difference of each line using the following formula:

[0048] ;

[0049] ;

[0050] In the above formula, For the line Adjust the power difference. For the line The power flow cycle difference, The periodic time constant, For the line The reference power value, To prevent division by zero of extremely small constants, For the line No. Power value per cycle, For the line No. Power value per cycle;

[0051] The over-limit line marking unit is used to compare the adjustment power difference of each line with a preset power change threshold. Perform an absolute value comparison, if If so, the power fluctuation of the line is within the normal allowable range; if If so, the line is marked as an over-limit line.

[0052] Thirdly, the present invention proposes a flexible power flow control device for power grids based on DC technology, including a processor and a memory;

[0053] The memory is used to store computer program code and to transmit the computer program code to the processor;

[0054] The processor is used to execute the aforementioned flexible power flow control method based on DC technology according to the instructions in the computer program code.

[0055] Fourthly, the present invention provides a computer storage medium on which a computer program is stored;

[0056] When the computer program is executed by the processor, it implements the steps of the aforementioned flexible power flow control method for a power grid based on DC technology.

[0057] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0058] 1. This invention proposes a flexible power flow control method, system, and equipment for power grids based on DC technology. The method first calculates the power flow data of each DC transmission line in real time, generating a standardized real-time DC power flow dataset. Then, based on the real-time DC power flow dataset, it calculates the adjustment power difference for each line and filters out over-limit lines based on the adjustment power difference. Finally, it calculates the adjustment voltage deviation of each over-limit line and generates flexible power flow control commands. On the one hand, this method addresses the problem of uneven power distribution in the power grid under UHV main transformers by integrating multi-source data in real time to construct a dynamic monitoring system, achieving multi-dimensional continuous tracking of voltage, current, and power flow, and improving the real-time performance of data acquisition and global perception capabilities. On the other hand, by calculating the adjustment power difference, this method quickly locates abnormal sections, filters out over-limit lines in the power grid, shortens the response delay to power surges, reduces the risk of regulation oscillations, and ensures the dynamic stability and transmission reliability of the power grid.

[0059] 2. This invention proposes a flexible power flow control method, system, and equipment for power grids based on DC technology. When calculating the adjustment voltage deviation of each over-limit line, this method, on the one hand, integrates multi-dimensional analysis of firing angle, arc extinguishing angle, and current parameters to accurately quantify the adjustment status and adjustment requirements of the corresponding converter station of the over-limit line and optimize the matching degree of adjustment strategy; on the other hand, based on the adjustment voltage deviation, it dynamically adjusts the firing angle adjustment amplitude to simultaneously balance voltage stability and power transmission requirements, improve cross-regional power coordination efficiency, and enhance the anti-disturbance capability under new energy fluctuations.

[0060] 3. This invention proposes a flexible power flow control method, system, and equipment for power grids based on DC technology. This method calculates the adjustment power difference of each line based on the power flow cycle difference of the lines. On the one hand, through real-time feedback of the cycle difference, the power flow of the power grid can be accurately adjusted to prevent the power grid from over-responding or under-responding, avoid system oscillation and over-regulation, and ensure that the power system maintains stability and efficiency in dynamic changes. On the other hand, through adaptive power adjustment, power dispatch and load distribution are optimized, enhancing the power grid's ability to resist disturbances in the face of load fluctuations and sudden events, and improving the overall system efficiency. Attached Figure Description

[0061] Figure 1 This is an overall flowchart of the method described in this invention.

[0062] Figure 2 This is a flowchart illustrating the acquisition of the real-time DC power flow dataset as described in Example 1.

[0063] Figure 3 This is a flowchart illustrating the process of obtaining the list of abnormal power flow sections as described in Example 1.

[0064] Figure 4 This is a flowchart illustrating the process of obtaining the converter station regulation potential table as described in Example 1.

[0065] Figure 5 This is a flowchart illustrating the acquisition of the power grid power flow flexible control command set described in Example 1;

[0066] Figure 6 This is a flowchart of the process for obtaining the power flow flexible control configuration set as described in Example 1.

[0067] Figure 7 This is a structural diagram of the system described in this invention.

[0068] Figure 8 This is a structural diagram of the device described in Example 3. Detailed Implementation

[0069] The present invention will now be described in further detail with reference to specific embodiments and accompanying drawings.

[0070] This invention proposes a flexible power flow control method, system, and equipment for power grids based on DC technology. By constructing a real-time multi-source data monitoring system, it continuously tracks voltage, current, and power flow, and quickly locates over-limit lines by comparing the adjusted power difference with dynamic thresholds. It integrates parameters such as firing angle, arc extinguishing angle, and current to quantify the regulation capability of converter stations, calculates the adjusted voltage deviation of each over-limit line, and dynamically adjusts the firing angle closed-loop feedback to balance voltage stability and power demand. Based on periodic evaluation and self-iterative generation of control sets from historical data, it improves cross-regional power coordination and disturbance rejection capabilities, and reduces oscillation risks.

[0071] Example 1:

[0072] like Figure 1 As shown, a flexible power flow control method for power grids based on DC technology is performed in the following steps:

[0073] 1. Calculate the power flow data of each DC transmission line in real time and generate a standardized real-time DC power flow dataset;

[0074] The real-time DC power flow dataset specifically includes real-time line voltage values, real-time line current values, calculated power flow values, and timing alignment results. Its acquisition process is as follows: Figure 2 As shown.

[0075] First, acquire and connect the DC transmission module, converter station monitoring terminal, and DC circuit breaker status sensor in the converter station, detect the voltage and current values ​​of each DC transmission line, match and store the voltage and current values ​​according to the line code, and generate an original set of operating parameters containing a triplet of line code, voltage value, and current value.

[0076] For example, converter station maintenance personnel use the RS485 communication protocol to establish a physical connection between the ±800kV DC transmission module and the SCADA system. A HIOKI3390 voltage sensor with an accuracy class of 0.2 is deployed at the outlet of Pole I, and a LEMITN600-S current sensor with a range of 0-6000A is installed on the smoothing reactor side. The acquisition period is set to 10ms via the ModbusTCP protocol. When the voltage value U=515.3kV of Pole II is detected, the system automatically generates a hexadecimal address code 0x0002 as the line identifier, binds the instantaneous current value I=2987A with the address code, and writes it to the Redis time-series database. For example, at the time node 2023-05-15T14:23:15.235, when U=512.8kV and I=3012A were collected for the Pole III line, the system called a preset mapping table to convert the string "LINE_C" into a 3-byte identifier 0x4C494E. The triple (0x4C494E, 512800, 3012) was then stored in a MongoDB document collection after CRC32 verification. After completing the data acquisition of 12 DC lines within this time slice, the system generated a JSON object array containing timestamp, line code, voltage integer value, and current integer value fields. This array was transmitted to the data processing module via a Kafka message queue, forming a raw set of operating parameters containing 15360 sets / second of data records.

[0077] Then, the voltage and current values ​​in the original set of operating parameters are called, the product of the voltage and current values ​​of each line is calculated in real time, the calculation results are bound with the corresponding line code and timestamp, the power flow data is arranged in millisecond time series, and a power flow time series with timestamp is generated.

[0078] For example, read the pole I line data within the time window [2023-05-15T14:23:15.000, 2023-05-15T14:23:15.999] and extract the voltage value of the nth record. (Unit: Volt) and Current Value (Unit: Ampere) Perform fixed-point multiplication. For example, when , At that time, the calculation yielded The system converts the calculation results into double-precision floating-point numbers according to the IEEE 754 standard, and appends a nanosecond-level timestamp 2023-05-15T14:23:15.235123456. It constructs a triplet containing the line code (0x0001), power value (1.5445536e6), and timestamp, and aligns the power values ​​of the 12 lines using a circular buffer. When a time deviation exceeding 200μs is detected, the NTP time synchronization service is invoked for clock synchronization, ultimately generating a power stream sequence arranged at 1ms intervals. For example, at 14:23:15.235, the system encapsulates the power values ​​of the 12 lines into an array of structures, each containing an 8-byte timestamp, a 3-byte line ID, and an 8-byte power value field. This is pushed to the real-time database via the ZeroMQ protocol, forming a time-series data stream of 1000 frames per second, with 12 records per frame.

[0079] Finally, power flow data of all lines in the power flow time series are extracted, data nodes of each line are aligned according to timestamp, and the data of the same time nodes of different lines are integrated into a multi-dimensional array structure to establish a three-dimensional data matrix containing time dimension, line dimension and power dimension, and generate a standardized real-time DC power flow dataset.

[0080] For example, the data processing unit allocates a three-dimensional tensor storage area, with dimensions set to [time axis × line axis × parameter axis]. When a timestamp is received... When processing data frames, the parser first checks the time difference values ​​of the 12 records within the frame. If the maximum time difference... This is considered as synchronized data, and will The time point is normalized to a reference point. For example, 14:23:15.235123456 is truncated to 14:23:15.235000000, and the power value of Pole I line, 1,544,553.6kW, is stored in the tensor location. The power value of Pole II line is 1,492,876.8 kW. This process is repeated to complete the matrix filling for 12 lines. When an extreme [something] is detected... When line data is missing, the previous time series point is used. The power values ​​are interpolated. For the time dimension, the system maintains a circular queue of length 3000. Each queue element contains a 12×1 power vector at time 14:23:15.235. When the queue is full (3000×12×1), the three-dimensional data block is converted into an HDF5 format file. The file header contains metadata such as a line code lookup table, dimensional description (kW), and sampling rate (1000Hz). For example, the file 20230515_142315.h5 is generated, with its dataset path being / PowerFlow / TensorData. The attribute set records traceability information such as voltage transformer ratio (800kV / 5V) and current transformer ratio (6000A / 1mA). Finally, a structured dataset conforming to the IEC61850 standard is output.

[0081] 2. Based on the real-time DC power flow dataset, calculate the adjustment power difference for each line, and filter out lines exceeding limits based on the adjustment power difference to generate a list of abnormal power flow sections. The acquisition process is as follows: Figure 3 As shown;

[0082] First, the continuous periodic power flow of each line in the real-time DC power flow dataset is retrieved, the power flow data of the current period and the previous period are extracted, the difference between the two is calculated, and a power flow period difference matrix containing line codes and period differences is generated:

[0083] ;

[0084] In the above formula, For the line The power flow cycle difference, For the line No. Power value per cycle, For the line No. Power value per cycle;

[0085] For example, 500 consecutive sampling points of the inner pole I line within the time window [2023-05-15T14:23:15.000, 2023-05-15T14:23:15.500] are read from a real-time DC power flow dataset in HDF5 format, and the first sampling point is extracted. Power value of each cycle (timestamp 14:23:15.499) and the Power value of each cycle (14:23:15.499) Calculate the period difference The system binds the line code 0x0001 to the difference value. For each line, the system creates a data structure containing a 4-byte floating-point difference field. The calculation results for the 12 lines are arranged in encoding order into a 12×1 matrix and stored as a CSV file. The file header contains the fields "Line Code, Difference (kW)". For example, the difference value for the 7th line with code 0x0007 is... At that time, write (0x0007, 856.7) in the 7th row of the matrix. After completing the calculation of all lines, generate the difference matrix file 20230515_142315_Pdiff.csv containing the timestamp field.

[0086] Then, based on the power flow period difference matrix, the adjusted power difference of each line is calculated using the following formula:

[0087] ;

[0088] In the above formula, For the line Adjust the power difference. The periodic time constant, For the line The reference power value, To prevent division by zero of extremely small constants;

[0089] The power adjustment difference of each line is compared with the preset power change threshold. Perform an absolute value comparison, if If so, the power fluctuation of the line is within the normal allowable range; if If so, the line is marked as an over-limit line;

[0090] In the process of power flow control, in addition to directly comparing the power flow cycle difference, dynamic power adjustment is also required. By calculating and adjusting the power difference, it is possible to ensure that the system can accurately respond to voltage fluctuations and remain stable, better control the distribution of power flow, avoid over-adjustment or under-adjustment, and help achieve more accurate and real-time power grid regulation. This improves the stability, flexibility and reliability of the power grid and ensures the smooth operation of the power grid under complex operating conditions.

[0091] For example, a preset power change threshold. (Set according to State Grid standard Q / GDW11372-2015). Reference power value for pole II line. (Integer value of average power over the last 24 hours), set the period time constant. (Determined according to the transient response standard of power system), minimum constant When detected Adjust the power difference at that time. The result shows that the standardized power variation rate of the Pole II line is -3.66%, which is less than the system's set 5% power variation threshold, indicating that the power fluctuation of this line is within the normal allowable range. The threshold deviation coefficient was calculated. The system stores the threshold deviation coefficients of the 12 lines into a floating-point array. When the extreme XI line is detected... When the power difference exceeds the power change threshold of 0.002 (i.e., 0.2%), the line is marked as an over-limit line.

[0092] Finally, iterate through the adjusted power difference of all lines, filter the line codes whose absolute values ​​exceed the preset power change threshold, classify and aggregate them by voltage level, and establish a list of abnormal power flow sections that includes the over-limit line codes, deviation coefficients, and occurrence times.

[0093] For example, iterate through the adjustment power difference array, when the pole XI line's When the occurrence time is recorded, extract the line code 0x000B and record the occurrence time as 2023-05-15T14:23:15.235. During classification, determine the voltage level based on the first digit of the line code: lines starting with 0x0 are ±800kV lines, and lines starting with 0x1 are ±500kV lines. For example, the code 0x000B is classified as an 800kV line. When a pole VII line... At that time, the system generates a JSON object {"Line Code": "0x0007", "Deviation Coefficient": 0.1%, "Timestamp": "2023-05-15T14:23:15.235"}. After aggregating all out-of-limit records, a hash table is created according to voltage level. The key is the voltage level string (e.g., "800kV"), and the value is an array of structures. Each structure contains a 3-byte line code, a 4-byte floating-point deviation coefficient, and an 8-byte timestamp field. Finally, a CSV format list file is generated, with the header containing the fields "Voltage Level, Line Code, Deviation Coefficient, Occurrence Time". For example, it records the deviation data of line 0x000B under the 800kV level, completing the construction of the abnormal power flow section list.

[0094] 3. Read the current trigger angle of the converter station corresponding to the over-limit line, calculate the regulation efficiency coefficient of each over-limit line, and generate a converter station regulation potential table. The acquisition process is as follows: Figure 4 As shown;

[0095] First, the over-limit line code in the abnormal power flow section list is called, and the current trigger angle value, arc extinguishing angle value and current control setting value of the corresponding converter station are read. It is determined whether the current trigger angle exceeds the preset adjustment range of the trigger angle. If it does not exceed the range, a status flag "1" is generated; if it exceeds the range, a status flag "0" is generated. A trigger angle adjustment flag set containing the over-limit line code and the trigger angle status flag is generated.

[0096] For example, the preset adjustment range of the trigger angle is set according to the GB / T13422-2018 standard. Adjustment range median Read the line code 0x000B of pole XI from the abnormal power flow section list, access the converter station control unit via the OPCUA protocol, and obtain the current trigger angle. Determine if it satisfies Generate status flag "1" (adjustable); when the polarity IX line trigger angle When an out-of-limit line is detected, a status flag "0" (beyond the lower limit) is generated. The system creates a structure for each out-of-limit line, containing a 2-byte encoding, a 1-byte status flag (0 / 1), and a 4-byte floating-point trigger angle value. For example, the structure for encoding 0x000B is {0x000B, 1, 25.3}. After detecting 12 abnormal lines, a CSV file containing fields for "out-of-limit line encoding, status flag, and trigger angle value" is generated.

[0097] Then, based on the trigger angle adjustment flag set, the difference between the arc extinguishing angle value and the optimal arc extinguishing angle, the current control setpoint, and the offset between the trigger angle value and the median of the adjustment range are jointly calculated to obtain the adjustment efficiency coefficient of each over-limit line with a status flag of "1":

[0098] ;

[0099] In the above formula, For the first The regulation efficiency coefficient of the over-limit line, For the first The arc extinguishing angle value of the over-limit line, The optimal arc-extinguishing angle reference value for the system. For the first The difference between the current control setpoint and the rated value of the over-limit circuit. For the first The trigger angle value of the over-limit line, , , These are the median, maximum, and minimum values ​​of the preset adjustment range for the trigger angle, respectively.

[0100] For example, take the parameters of Pole VII: acquire the arc extinguishing angle through a fiber optic sensor. The optimal arc-extinguishing angle reference value was calculated according to the IEC 60633 standard. Current control setpoint Rated current Calculate the difference Substituting into the formula, we get The results show that the regulation efficiency coefficient of the Pole VII line is 0.0487, and its value reflects the arc-extinguishing angle offset that can be corrected per unit current deviation. The efficiency coefficients of the 12 lines are stored in a double-precision floating-point array to generate a 12×1 matrix file efficiency_matrix.bin.

[0101] Finally, the trigger angle adjustment identifier set and the corresponding adjustment efficiency coefficient are integrated, the adjustment status mark and efficiency coefficient are matched according to the line code, and a three-dimensional data table containing the over-limit line code, status mark and adjustment efficiency coefficient is established to generate a standardized converter station adjustment potential table.

[0102] For example, the line status flag and regulation efficiency coefficient of pole VII are read and a three-dimensional tuple (0x0007, 1, 0.0487) is created. The system creates an independent dimension for each voltage level. For example, at the 800kV level, the regulation efficiency coefficients of the 6 lines are constructed into a 6×3 matrix, containing the fields "line code (3 bytes), status flag (1 byte), regulation efficiency coefficient (8 bytes)". After sorting the 12 line data in ascending order of code, they are written to a Parquet format file. The file metadata includes field descriptions, unit information (regulation efficiency coefficient is dimensionless), and a timestamp 2023-05-15T14:23:15.235. A standardized regulation potential table file regulation_potential.parquet is generated, in which the line efficiency coefficient with status flag 1 ranges from [0.035, 0.082], and the line efficiency coefficient field with status flag 0 is filled with NULL values.

[0103] 4. Based on the converter station regulation potential table, select converter stations with adjustable status, calculate the adjustment voltage deviation of each over-limit line, and generate a flexible power flow control command set. The acquisition process is as follows: Figure 5 As shown;

[0104] First, call the over-limit line code of the adjustable status in the converter station regulation potential table, read the current voltage value and target voltage setting value of the corresponding high voltage DC transmission line, calculate the absolute difference between the two values, and generate a voltage deviation vector containing the line code and voltage difference.

[0105] For example, the pole VII line code 0x0007 (status flag 1) is read from the converter station regulation potential table, and the current voltage value is obtained via the IEC 61850 protocol. Target voltage setpoint Calculate the absolute difference This generates a tuple (0x0007, 1.7). The system creates a structure array containing a 3-byte encoding and a 4-byte floating-point difference for each adjustable over-limit line. These are sorted in ascending order of encoding and stored as a binary file `voltage_diff.bin`. The file header contains a timestamp `2023-05-15T14:23:15.235` and a record number field. For example, the difference for line XII. At that time, write (0x000C, 3.2) at file offset 0x00A0.

[0106] Then, based on the voltage difference, the adjusted voltage deviation of each over-limit line marked with "1" is calculated using the following formula to generate the voltage regulation demand index:

[0107] ;

[0108] In the above formula, For the first Adjustment voltage deviation of the over-limit line. For the first The voltage difference between the two lines exceeding the limit. For the first The reference voltage value of the over-limit line. For smoothing coefficients, For the first The regulation efficiency coefficient of the over-limit line, This is the baseline value for the system's maximum regulation efficiency;

[0109] The adjusted voltage deviation of each over-limit line is compared with the preset voltage deviation threshold. Perform an absolute value comparison, if If , then the adjustment demand index "0" is generated; if If so, then the demand adjustment index "1" is generated;

[0110] For example, the voltage deviation threshold is set according to the GB / T12325-2008 standard. Pole-taking VII circuit parameters: reference voltage value (Rated voltage), smoothing factor (To prevent the denominator from being too small), adjust the efficiency coefficient. Maximum performance benchmark (Taking the maximum value from the adjustment potential table), calculate the adjustment voltage deviation. Its absolute value Therefore, the adjustment demand index is 0. When dealing with the XI pole line, the adjusted voltage deviation is calculated. The system generates a regulation demand index of 1. It then stores the regulation demand indices of the nine over-limit lines into a Boolean array.

[0111] Finally, iterate through the voltage regulation demand index of all over-limit lines, calculate the firing angle adjustment range of each over-limit line with a regulation demand index of "1", and determine whether the voltage difference of the over-limit line is less than 0. If so, mark the adjustment direction as "+" and increase the firing angle; otherwise, mark the adjustment direction as "-" and decrease the firing angle.

[0112] The adjustment range of the firing angle for each over-limit circuit with an adjustment demand index of "1" is calculated using the following formula:

[0113] ;

[0114] In the above formula, For the first The adjustment range of the trigger angle for each over-limit circuit;

[0115] Generate instruction tuples containing over-limit line codes, trigger angle adjustment amplitude, and adjustment direction based on timestamps, and establish a standardized power grid power flow flexible control instruction set;

[0116] For example, the adjustment demand index of the XI circuit is read as 1, and the current trigger angle is... According to the adjustment direction rules: when When necessary, the trigger angle needs to be increased (adjust the direction mark "+"), and the adjustment range needs to be calculated. The system generates an instruction tuple (0x000B, 0.868, "+"). For each over-limit line, the system creates a structure containing 3 bytes of encoding, 4 bytes of floating-point amplitude, and 1 byte of direction sign. A JSON array is generated based on the timestamp 14:23:15.235, containing the fields "timestamp", "line_id", "delta_angle", and "direction". For example, the Extreme XI instruction is {"timestamp":"2023-05-15T14:23:15.235", "line_id":"0x000B", "delta_angle":0.868", "direction":"+"}. Finally, a ZIP archive containing 6 instructions, adjust_commands_20230515_142315.zip, is generated and pushed to the execution units of each converter station via the MQTT protocol.

[0117] 5. Call the power flow flexible control instruction set, read the voltage, current, and power flow values ​​of the corresponding converter station of the over-limit line within the adjustment cycle, establish a power flow data table for each line after adjustment, extract the line data corresponding to the initial DC power flow real-time dataset, summarize the adjustment instructions, change range, and next adjustment cycle suggestions according to the line, and generate a power flow flexible control configuration set. The acquisition process is as follows: Figure 6 As shown.

[0118] The power flow flexible control configuration set specifically includes an adjusted power flow value table, a command effective period marker, a power flow change gradient value, and a periodic adjustment priority parameter. Based on the adjustment effect within a period and historical data, a control configuration set is generated, linking adjustment commands and execution results to form a closed-loop optimization, achieving strategy self-iteration and reducing reliance on manual intervention.

[0119] First, the line code in the power grid flow flexible control instruction set is called to read the voltage, current and power flow values ​​of the adjusted converter station within the adjusted period, and the data is stored according to the line code and timestamp to establish an adjusted power flow data table containing the adjusted operating parameters.

[0120] For example, the Pole XI line code 0x000B is read from the instruction set, and within the adjusted 5 cycles (time window [2023-05-15T14:23:20.000, 2023-05-15T14:23:25.000]), the voltage value sequence is acquired by the PMU device at a sampling rate of 1200Hz. Current value sequence Calculate the power flow sequence After aligning the data by timestamp, a CSV file containing fields "timestamp, line code, voltage (kV), current (A), power (MW)" is generated. For example, the record for 14:23:20.200 is (2023-05-15T14:23:20.200, 0x000B, 799.8, 2998, 2397.0). After collecting data for 6 adjusted lines, a PostgreSQL database table `adjusted_powerflow` is created with the primary key (line code, timestamp).

[0121] Then, extract all data of the corresponding line in the initial DC power flow real-time dataset, calculate the absolute difference between the adjusted power flow value and the initial power flow value, associate the difference with the power flow flexible control command according to the line code, and generate a power flow variation matrix containing the line code, adjustment range, and adjustment time.

[0122] For example, the baseline data for the Polar XI line is extracted from the initial real-time DC power flow dataset: at timestamp 14:23:15.235. , , At the adjusted time of 14:23:20.200, the voltage difference of the XI line is... Current difference power difference The system generates a change vector (0x000B, 4.2, 13, 22.1) and associates it with the adjustment command "+0.868°". The system creates a 3D matrix file delta_matrix.h5, where each element contains the line code, adjustment magnitude, and time difference (in seconds). For example, the entry for pole XI is (0x000B, 22.1, 5.0).

[0123] Finally, the adjusted power flow data table and power flow variation matrix are integrated, the effect of the adjustment command is summarized according to the line code, and the suggested time interval for the next adjustment cycle is calculated in combination with the current system operation cycle. A four-dimensional data set containing line code, adjustment command, variation amplitude and suggested cycle is generated to establish a standardized power flow flexible control configuration set.

[0124] For example, read the adjustment command "+0.868°" for the XI line and the power change of 22.1MW, and calculate the adjustment efficiency. According to GB / T26399-2011, the maximum adjustment frequency is set to 0.2Hz (i.e., a minimum interval of 5 seconds). When the current cycle is detected to be 14:23:25.000, the next adjustment time is recommended. This generates a four-dimensional tuple (0x000B, "+0.868°", 22.1, 5.0). Finally, a MongoDB collection `flex_control_config` is constructed, with a document structure of {"line code": "0x000B", "instruction": "+0.868°", "variation range": 22.1, "recommended period": 5.0}. After integrating the data from the six lines, a Parquet format file `control_config_set.parquet` is output, containing a four-dimensional index with timestamps, line dimensions, instruction dimensions, and period dimensions.

[0125] Example 2:

[0126] like Figure 7 As shown, a flexible power flow control system for power grids based on DC technology includes a real-time dataset generation module, an over-limit line screening module, and a flexible control command generation module.

[0127] The real-time dataset generation module is used to calculate the power flow data of each DC transmission line in real time and generate a standardized real-time DC power flow dataset.

[0128] The over-limit line screening module is used to calculate the adjustment power difference of each line based on the real-time DC power flow dataset, and to screen over-limit lines based on the adjustment power difference.

[0129] The flexible control command generation module is used to calculate the adjustment voltage deviation of each over-limit line and generate flexible power flow control commands.

[0130] The over-limit line screening module includes an adjustment power difference calculation unit and an over-limit line marking unit;

[0131] The adjusted power difference calculation unit is used to call the continuous periodic power flow of each line in the real-time DC power flow dataset and calculate the adjusted power difference of each line using the following formula:

[0132] ;

[0133] ;

[0134] In the above formula, For the line Adjust the power difference. For the line The power flow cycle difference, The periodic time constant, For the line The reference power value, To prevent division by zero of extremely small constants, For the line No. Power value per cycle, For the line No. Power value per cycle;

[0135] The over-limit line marking unit is used to compare the adjustment power difference of each line with a preset power change threshold. Perform an absolute value comparison, if If so, the power fluctuation of the line is within the normal allowable range; if If so, the line is marked as an over-limit line.

[0136] The flexible control command generation module includes a status flag generation unit, an adjustment voltage deviation calculation unit, an adjustment demand index generation unit, a trigger angle adjustment amplitude calculation unit, and a power grid flow flexible control command generation unit.

[0137] The status flag generation unit is used to read the current trigger angle of the converter station corresponding to the over-limit line, and determine whether the current trigger angle exceeds the preset adjustment range of the trigger angle. If it does not exceed the range, a status flag "1" is generated; if it exceeds the range, a status flag "0" is generated.

[0138] The voltage deviation calculation unit is used to calculate the voltage deviation of each over-limit line with a status mark of "1".

[0139] The adjustment demand index generation unit is used to compare the adjustment voltage deviation of each over-limit line with a preset voltage deviation threshold. Perform an absolute value comparison, if If , then the adjustment demand index "0" is generated; if Then, the adjustment demand index "1" is generated, where For the first Adjustment voltage deviation of the over-limit line;

[0140] The trigger angle adjustment range calculation unit is used to calculate the trigger angle adjustment range of each over-limit line with an adjustment demand index of "1", and to determine whether the voltage difference of the over-limit line is less than 0. If it is, the adjustment direction mark is "+", and the trigger angle needs to be increased; if it is not, the adjustment direction mark is "-", and the trigger angle needs to be decreased.

[0141] The power grid flow flexible control command generation unit is used to generate power grid flow flexible control commands based on the trigger angle adjustment amplitude and adjustment direction of each over-limit line.

[0142] In the voltage deviation calculation unit, the voltage deviation of each over-limit line marked with "1" is calculated using the following formula:

[0143] ;

[0144] ;

[0145] In the above formula, For the first Adjustment voltage deviation of the over-limit line. For the first The voltage difference of the over-limit line, i.e., the first The absolute difference between the current voltage value and the target voltage setting value of the corresponding high-voltage direct transmission line for each over-limit line. For the first The reference voltage value of the over-limit line. For smoothing coefficients, For the first The regulation efficiency coefficient of the over-limit line, This is the baseline value for the system's maximum regulating efficiency. For the first The arc extinguishing angle value of the over-limit line, The optimal arc-extinguishing angle reference value for the system. For the first The difference between the current control setpoint and the rated value of the over-limit circuit. For the first The trigger angle value of the over-limit line, , , These are the median, maximum, and minimum values ​​of the preset adjustment range for the trigger angle, respectively.

[0146] In the trigger angle adjustment range calculation unit, the trigger angle adjustment range of each over-limit line with an adjustment demand index of "1" is calculated using the following formula:

[0147] ;

[0148] In the above formula, For the first The trigger angle adjustment range of the over-limit circuit.

[0149] Example 3:

[0150] like Figure 8 As shown, a power grid power flow flexible control device based on DC technology includes a processor and a memory;

[0151] The memory is used to store computer program code and to transmit the computer program code to the processor;

[0152] The processor is used to execute, according to the instructions in the computer program code, a flexible power flow control method for a power grid based on DC technology as described in Embodiment 1.

[0153] Example 4:

[0154] A computer storage medium on which computer programs are stored;

[0155] When the computer program is executed by the processor, it implements the steps of the flexible power flow control method for a power grid based on DC technology described in this scheme.

Claims

1. A flexible power flow control method for power grids based on DC technology, characterized in that, The method includes: S1. Calculate the power flow data of each DC transmission line in real time and generate a standardized real-time DC power flow dataset; S2. Based on the real-time DC power flow dataset, calculate the adjustment power difference of each line, and filter out lines exceeding the limit based on the adjustment power difference; S3. Calculate the adjustment voltage deviation of each over-limit line and generate flexible power flow control commands.

2. The flexible power flow control method for power grids based on DC technology according to claim 1, characterized in that, S3 includes: S31. Read the current trigger angle of the converter station corresponding to the over-limit line, and determine whether the current trigger angle exceeds the preset adjustment range of the trigger angle. If it does not exceed the range, generate a status flag "1"; if it exceeds the range, generate a status flag "0". S32. Calculate the adjustment voltage deviation of each over-limit line with status mark "1"; S33. Compare the adjusted voltage deviation of each over-limit line with the preset voltage deviation threshold. Perform an absolute value comparison, if If , then the adjustment demand index "0" is generated; if Then, the adjustment demand index "1" is generated, where For the first Adjustment voltage deviation of the over-limit line; S34. Calculate the firing angle adjustment range for each over-limit line with an adjustment demand index of "1", and determine whether the voltage difference of the over-limit line is less than 0. If so, mark the adjustment direction "+" and increase the firing angle; if not, mark the adjustment direction "-" and decrease the firing angle. S35. Based on the trigger angle adjustment range and adjustment direction of each over-limit line, generate flexible power flow control commands.

3. The flexible power flow control method for power grids based on DC technology according to claim 2, characterized in that, In step S32, the adjustment voltage deviation of each over-limit line marked with "1" is calculated using the following formula: ； ； In the above formula, For the first Adjustment voltage deviation of the over-limit line. For the first The voltage difference of the over-limit line, i.e., the first The absolute difference between the current voltage value and the target voltage setting value of the corresponding high-voltage direct transmission line for each over-limit line. For the first The reference voltage value of the over-limit line. For smoothing coefficients, For the first The regulation efficiency coefficient of the over-limit line, This is the baseline value for the system's maximum regulating efficiency. For the first The arc extinguishing angle value of the over-limit line, The optimal arc-extinguishing angle reference value for the system. For the first The difference between the current control setpoint and the rated value of the over-limit circuit. For the first The trigger angle value of the over-limit line, , , These are the median, maximum, and minimum values ​​of the preset adjustment range for the trigger angle, respectively. In S34, the firing angle adjustment range of each over-limit line with an adjustment demand index of "1" is calculated using the following formula: ； In the above formula, For the first The trigger angle adjustment range of the over-limit circuit.

4. The flexible power flow control method for power grids based on DC technology according to claim 1, characterized in that, S2 includes: S21. Calculate the adjustment power difference for each line using the following formula, by retrieving the continuous periodic power flow from the real-time DC power flow dataset for each line: ； ； In the above formula, For the line Adjust the power difference. For the line The power flow cycle difference, The periodic time constant, For the line The reference power value, To prevent division by zero of extremely small constants, For the line No. Power value per cycle, For the line No. Power value per cycle; S22. Compare the adjusted power difference of each line with the preset power change threshold. Perform an absolute value comparison, if If so, the power fluctuation of the line is within the normal allowable range; if If so, the line is marked as an over-limit line.

5. A flexible power flow control system for power grids based on DC technology, characterized in that, The system includes a real-time dataset generation module, an over-limit line screening module, and a flexible control command generation module. The real-time dataset generation module is used to calculate the power flow data of each DC transmission line in real time and generate a standardized real-time DC power flow dataset. The over-limit line screening module is used to calculate the adjustment power difference of each line based on the real-time DC power flow dataset, and to screen over-limit lines based on the adjustment power difference. The flexible control command generation module is used to calculate the adjustment voltage deviation of each over-limit line and generate flexible power flow control commands.

6. A flexible power flow control system for a power grid based on DC technology according to claim 5, characterized in that, The flexible control command generation module includes a status flag generation unit, an adjustment voltage deviation calculation unit, an adjustment demand index generation unit, a trigger angle adjustment amplitude calculation unit, and a power grid flow flexible control command generation unit. The status flag generation unit is used to read the current trigger angle of the converter station corresponding to the over-limit line, determine whether the current trigger angle exceeds the preset adjustment range of the trigger angle, and generate a status flag "1" if it does not exceed the preset adjustment range. If it exceeds the limit, a status flag "0" is generated; The voltage deviation calculation unit is used to calculate the voltage deviation of each over-limit line with a status mark of "1". The adjustment demand index generation unit is used to compare the adjustment voltage deviation of each over-limit line with a preset voltage deviation threshold. Perform an absolute value comparison, if If , then the adjustment demand index "0" is generated; if Then, the adjustment demand index "1" is generated, where For the first Adjustment voltage deviation of the over-limit line; The trigger angle adjustment range calculation unit is used to calculate the trigger angle adjustment range of each over-limit line with an adjustment demand index of "1", and to determine whether the voltage difference of the over-limit line is less than 0. If it is, the adjustment direction mark is "+", and the trigger angle needs to be increased; if it is not, the adjustment direction mark is "-", and the trigger angle needs to be decreased. The power grid flow flexible control command generation unit is used to generate power grid flow flexible control commands based on the trigger angle adjustment amplitude and adjustment direction of each over-limit line.

7. A flexible power flow control system for a power grid based on DC technology according to claim 6, characterized in that, In the voltage deviation calculation unit, the voltage deviation of each over-limit line with a status mark of "1" is calculated using the following formula: ； ； In the above formula, For the first Adjustment voltage deviation of the over-limit line. For the first The voltage difference of the over-limit line, i.e., the first The absolute difference between the current voltage value and the target voltage setting value of the corresponding high-voltage direct transmission line for each over-limit line. For the first The reference voltage value of the over-limit line. For smoothing coefficients, For the first The regulation efficiency coefficient of the over-limit line, This is the baseline value for the system's maximum regulating efficiency. For the first The arc extinguishing angle value of the over-limit line, The optimal arc-extinguishing angle reference value for the system. For the first The difference between the current control setpoint and the rated value of the over-limit circuit. For the first The trigger angle value of the over-limit line, , , These are the median, maximum, and minimum values ​​of the preset adjustment range for the trigger angle, respectively. In the trigger angle adjustment range calculation unit, the trigger angle adjustment range of each over-limit line with an adjustment demand index of "1" is calculated using the following formula: ； In the above formula, For the first The trigger angle adjustment range of the over-limit circuit.

8. A flexible power flow control system for a power grid based on DC technology according to claim 5, characterized in that, The over-limit line screening module includes an adjustment power difference calculation unit and an over-limit line marking unit; The adjusted power difference calculation unit is used to call the continuous periodic power flow of each line in the real-time DC power flow dataset and calculate the adjusted power difference of each line using the following formula: ； ； In the above formula, For the line Adjust the power difference. For the line The power flow cycle difference, The periodic time constant, For the line The reference power value, To prevent division by zero of extremely small constants, For the line No. Power value per cycle, For the line No. Power value per cycle; The over-limit line marking unit is used to compare the adjustment power difference of each line with a preset power change threshold. Perform an absolute value comparison, if If so, the power fluctuation of the line is within the normal allowable range; if If so, the line is marked as an over-limit line.

9. A flexible power flow control device for power grids based on DC technology, characterized in that, Including the processor and memory; The memory is used to store computer program code and to transmit the computer program code to the processor; The processor is used to execute, according to the instructions in the computer program code, a power flow flexible control method based on DC technology as described in any one of claims 1-4.

10. A computer storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the steps of the power flow flexible control method for a power grid based on DC technology as described in any one of claims 1-4.

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