A method for adaptive regulation of transmission line voltage in both directions

Abstract

The application discloses a kind of transmission line bidirectional voltage adaptive regulation methods, comprising the following steps: obtaining the real-time sampling data of transmission line sending end voltage and receiving end voltage, calculating sending end voltage deviation and receiving end voltage deviation, and determining voltage out-of-limit direction;According to the current operating condition parameters of transmission line, dynamically calculate the voltage high trigger threshold and the voltage low trigger threshold, and according to the comparison result, match the corresponding voltage regulation strategy from the multi-source coordination strategy library;According to the voltage regulation strategy matched, generate coordinated control instruction, and issue to the voltage regulation equipment along the transmission line to execute regulation;The adjustment result data is input into the self-learning optimization model, and the trigger threshold parameter and strategy weight are updated.The application can simultaneously cope with voltage out-of-limit in two directions of voltage high and voltage low, and adjust the trigger threshold according to the operating condition, which is beneficial to improve the voltage quality of transmission line.

Description

Technical Field

[0001] This invention specifically relates to the field of power system voltage control technology, and in particular to a bidirectional voltage adaptive regulation method for transmission lines. Background Technology

[0002] Transmission lines are the main channels for long-distance transmission of electricity. With the large-scale integration of renewable energy into the power grid in the form of distributed power sources, the electricity consumption behavior on the load side is becoming increasingly diverse, the peak-valley difference is constantly widening, and the voltage along the transmission lines frequently exceeds the limit in both directions, that is, the same line may alternate between two states of high voltage and low voltage at different times.

[0003] Existing voltage regulation methods for transmission lines mainly include on-load tap changers, shunt reactors, capacitor banks, and static var compensators (SVCs) and static synchronous compensators (SNCs) based on power electronic devices. These regulation devices have the following shortcomings in actual operation: First, the adjustment direction is singular or asymmetrical. Traditional on-load tap changers and capacitor bank regulation strategies are mostly designed for scenarios with low voltage. When the voltage is high, the adjustment response is slow, and there is a lack of regulation mechanisms that can handle the two directions of high and low voltage separately.

[0004] Second, the trigger threshold is fixed. Most existing solutions set the voltage over-limit trigger threshold to a fixed value, which cannot be dynamically adjusted according to the current load level of the line, the output status of distributed power sources, and line impedance, etc. This makes it easy to trigger the regulation action erroneously during the off-peak load period, while the best regulation opportunity may be missed during the peak load period.

[0005] Third, there is insufficient coordination capability among multiple devices. When multiple regulating devices such as on-load tap changers, capacitor banks, and static var compensators are installed along the transmission line, the existing solutions usually rely on manual experience or preset fixed priorities to call them one by one, making it difficult for various devices to complement each other in terms of response speed, regulation precision, and regulation cost.

[0006] Fourth, there is a lack of predictive and self-learning capabilities. Most existing regulation schemes adopt a feedback control mode based on current sampled values, which cannot combine historical load data to predict future voltage changes and adjust in advance, nor can they optimize regulation parameters online based on historical regulation effects.

[0007] Therefore, a method for regulating transmission line voltage is needed that can simultaneously address both high and low voltage, adjust trigger thresholds based on operating parameters, coordinate multiple regulating devices, and possess predictive and self-learning capabilities. Summary of the Invention

[0008] To address the aforementioned problems in the existing technology, this invention proposes a bidirectional voltage adaptive adjustment method for transmission lines.

[0009] To achieve the above objectives, the present invention adopts the following technical solution: A method for bidirectional voltage adaptive regulation of transmission lines includes the following steps: S1: Acquire real-time sampling data of the voltage at the sending end and the voltage at the receiving end of the transmission line, and calculate the voltage deviation at the sending end and the voltage deviation at the receiving end based on the real-time sampling data; S2: Determine the voltage over-limit direction based on the voltage deviation at the sending end and the voltage deviation at the receiving end. The voltage over-limit direction includes the direction of voltage over-limit and the direction of voltage under-limit. S3: Based on the current operating parameters of the transmission line, dynamically calculate the high voltage trigger threshold and the low voltage trigger threshold to obtain the bidirectional adaptive trigger threshold. S4: Based on the comparison result between the voltage over-limit direction and the bidirectional adaptive trigger threshold, match the corresponding voltage regulation strategy from the preset multi-source coordination strategy library; S5: According to the matched voltage regulation strategy, generate coordinated control instructions for at least two types of voltage regulation equipment configured along the transmission line, and send them to each voltage regulation equipment to perform regulation operations. S6: Collect the adjustment result data of this adjustment operation, and input the adjustment result data into the preset self-learning optimization model to iteratively update the parameters of the bidirectional adaptive trigger threshold and the strategy weights of the multi-source coordination strategy library.

[0010] The beneficial effects of this invention are as follows: 1. By setting the high voltage trigger threshold and the low voltage trigger threshold independently, the trigger sensitivity in the two directions is different. This allows for different adjustment methods to be adopted for voltage over-limit in the two directions of the transmission line, avoiding the problems of false triggering or slow response when using a single threshold.

[0011] 2. By establishing a multi-source coordination strategy library and matching adjustment strategies according to the direction of voltage over-limit, it is possible to coordinate various types of voltage regulation equipment, so that each type of equipment can complement each other in terms of response speed, adjustment precision and adjustment cost, thereby improving the overall regulation efficiency and voltage quality.

[0012] 3. By setting up a predictive pre-regulation mechanism, voltage changes can be predicted based on historical data, and regulation actions can be triggered in advance before voltage exceeds the limit. Furthermore, simulation verification can be performed using a digital twin model to make voltage regulation more timely.

[0013] 4. By using a self-learning optimization model to iteratively update the trigger threshold and strategy weights online, the adjustment parameters gradually approach the optimal configuration suitable for the current line, making the solution more adaptable to different lines and different operating conditions. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the process proposed in this invention; Figure 2 This is a block diagram of the system components proposed in this invention. Detailed Implementation

[0015] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0016] Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this patent, and should not be construed as limiting this patent.

[0017] refer to Figure 1 This invention provides an overall process for a bidirectional voltage adaptive regulation method for transmission lines. This embodiment uses a 220kV transmission line as an example. Along this line, there is one set of on-load tap changers, one set of shunt reactors, two sets of capacitor banks, and one static var compensator. Voltage sampling points and load measurement points are provided at both the sending and receiving ends of the line.

[0018] The bidirectional voltage adaptive regulation method for transmission lines provided in this embodiment includes the following steps: S1: Obtain real-time sampling data of the sending-end voltage and receiving-end voltage of the transmission line, and calculate the sending-end voltage deviation and receiving-end voltage deviation based on the real-time sampling data.

[0019] In this embodiment, the sampling frequency of both the sending-end voltage and the receiving-end voltage is set to 4 times per second, and the sampling data is obtained through the phasor measurement unit of the transmission line monitoring system.

[0020] The sending-end voltage deviation is the difference between the actual sending-end voltage and the rated sending-end voltage, and the receiving-end voltage deviation is the difference between the actual receiving-end voltage and the rated receiving-end voltage. To avoid misjudgment caused by single sampling jitter, this implementation takes the sliding average of the four sampling points within the most recent second as the effective voltage value at that moment.

[0021] S2: Determine the voltage over-limit direction based on the voltage deviation at the sending end and the voltage deviation at the receiving end. The voltage over-limit direction includes the direction of voltage over-limit and the direction of voltage under-limit.

[0022] In this embodiment, when at least one of the sending-end voltage deviation and the receiving-end voltage deviation is greater than the preset zero threshold upper limit, the current voltage over-limit direction is determined to be the voltage over-limit direction. When at least one of the sending-end voltage deviation and the receiving-end voltage deviation is less than the preset zero threshold lower limit, the current voltage over-limit direction is determined to be the voltage low direction. When the voltage deviation at the sending end and the voltage deviation at the receiving end fall between the upper limit and the lower limit of the zero threshold, respectively, the current voltage is determined to be in the normal range and no adjustment action is triggered.

[0023] When the voltage deviation at the sending end and the voltage deviation at the receiving end correspond to different voltage over-limit directions, the transmission line is divided into multiple segmented adjustment zones. A multi-source coordination strategy library is preset. For each segmented adjustment area, the corresponding voltage adjustment strategy is matched in the multi-source coordination strategy library and sent to the voltage adjustment equipment in each segmented adjustment area to perform the adjustment operation. Among them, the voltage regulation strategies of adjacent segmented regulation regions are decoupled through preset coordination constraints.

[0024] S3: Based on the current operating parameters of the transmission line, dynamically calculate the high voltage trigger threshold and the low voltage trigger threshold to obtain the bidirectional adaptive trigger threshold.

[0025] In this embodiment, the high voltage trigger threshold and low voltage trigger threshold are dynamically calculated, including obtaining the active load, reactive load, distributed power generation output status, and line impedance parameters of the transmission line. The line voltage drop compensation is calculated based on the active and reactive loads, and the high voltage trigger threshold and low voltage trigger threshold are calculated based on the output status of the distributed power source and the line impedance parameters. Different calculation coefficients are used for the high voltage trigger threshold and the low voltage trigger threshold, so that the trigger sensitivity is different in the high voltage direction and the low voltage direction. The trigger sensitivity for the high voltage direction is lower than that for the low voltage direction, in order to avoid frequent initiation of the high voltage adjustment action during periods of high output from the distributed power source.

[0026] S4: Based on the comparison result between the voltage over-limit direction and the bidirectional adaptive trigger threshold, match the corresponding voltage regulation strategy from the preset multi-source coordination strategy library.

[0027] Voltage regulation strategies include: When the voltage exceeds the limit in the direction of high voltage, at least two of the following adjustment methods shall be selected in order of priority: lowering the tap position of the on-load tap changer, engaging the parallel reactor, discharging the inductive reactive power of the static var compensator, and disconnecting the capacitor bank. When the voltage exceeds the limit in the direction of low voltage, at least two of the following adjustment methods shall be selected in order of priority: adjusting the tap position of the on-load tap changer, connecting the capacitor bank, capacitive reactive power output of the static var compensator, and reactive power generation of the distributed power source.

[0028] The multi-source coordination strategy library stores multiple candidate regulation strategies for both the high voltage direction and the low voltage direction. Each candidate regulation strategy specifies the type of equipment involved, the priority order of each equipment, the regulation step size, and the timing of equipment actions.

[0029] In this embodiment, when the voltage over-limit direction is the direction of voltage over-limit, this implementation method preferentially selects two adjustment methods to be executed in combination: energizing the parallel reactor and lowering the tap position of the on-load tap changer. When the voltage exceeds the limit in the direction of low voltage, this implementation method prioritizes the coordinated execution of two adjustment methods: capacitor bank input and static var compensator capacitive reactive power output.

[0030] S5: Based on the matched voltage regulation strategy, generate coordinated control commands for at least two types of voltage regulation equipment configured along the transmission line, and send them to each voltage regulation equipment to perform regulation operations.

[0031] In S5, a digital twin model of the voltage regulation equipment for transmission lines was also established. The digital twin model reflects the operating status and response characteristics of each voltage regulation device in real time. Before generating coordinated control commands for each voltage regulation device, the regulation effect is first verified through simulation in a digital twin model. When the simulation verification results show that the adjustment effect does not meet the preset target, the voltage adjustment strategy is rematched and the simulation verification is performed again until the adjustment effect meets the preset target, and then the coordinated control command is issued.

[0032] In this embodiment, the coordination control command includes the start-up time of each participating device, the target level or target output value, and the timing coordination relationship between the devices. After receiving the coordination control command, each voltage regulating device executes the regulating action sequentially according to the preset timing coordination relationship, avoiding voltage surges caused by multiple devices operating simultaneously.

[0033] S6: Collect the adjustment result data of this adjustment operation, and input the adjustment result data into the preset self-learning optimization model to iteratively update the parameters of the bidirectional adaptive trigger threshold and the strategy weights of the multi-source coordination strategy library.

[0034] The preset self-learning optimization model includes: Based on historical load time series data and meteorological data, the voltage trend in the future preset period is predicted, and a voltage prediction curve is obtained. Based on the voltage prediction curve, the bidirectional adaptive triggering threshold is feedforward corrected to obtain the predicted corrected bidirectional adaptive triggering threshold. When the real-time sampled data approaches the predicted and corrected bidirectional adaptive trigger threshold, the corresponding voltage regulation strategy is triggered in advance.

[0035] Predicting voltage trends over a predetermined time period, including: A voltage prediction model is constructed using long short-term memory networks or gated recurrent unit networks; Using historical load time series data, historical voltage time series data, and meteorological time series data as input features, the output is the voltage prediction curve and prediction confidence interval for a future preset time period; If historical load time series data of the past 7 days, historical voltage time series data, and weather forecast data for the next 24 hours are used as input features, the output voltage prediction curve and prediction confidence interval for the next hour can be generated. The safety margin of the bidirectional adaptive triggering threshold is adaptively adjusted based on the predicted confidence interval; If the voltage prediction curve shows that the voltage is significantly higher than normal in the next hour, the high voltage trigger threshold will be adjusted downward by a safety margin. When the voltage prediction curve shows that the voltage is significantly lower than normal in the next hour, the low voltage trigger threshold will be adjusted upward by a safety margin.

[0036] The size of the safety margin is adjusted accordingly based on the width of the prediction confidence interval; the wider the prediction confidence interval, the larger the safety margin.

[0037] The adjustment action is set to be triggered in advance when the real-time sampled data enters a safe range of 0.8 times the trigger threshold, so as to allow sufficient adjustment time.

[0038] The self-learning optimization model uses the following update method: The evaluation indicators are the adjustment range of this adjustment operation, the convergence speed of the voltage deviation after adjustment, the number of equipment actions during the adjustment process, and the peak voltage fluctuation during the adjustment process. A multi-objective reward function is constructed based on the evaluation indicators, and the parameters of the bidirectional adaptive trigger threshold and the policy weights of the multi-source coordination policy library are updated online based on the multi-objective reward function. The update steps of the high voltage trigger threshold and the low voltage trigger threshold are independent of each other and can be adjusted separately based on the historical adjustment effect in their respective directions.

[0039] In this embodiment, the self-learning optimization model constructs a multi-objective reward function based on the above-mentioned indicators, and updates the weights of each candidate strategy in the multi-source coordination strategy library online based on the multi-objective reward function.

[0040] refer to Figure 2 This invention also provides a bidirectional voltage adaptive regulation system for transmission lines, the system comprising: The data acquisition module is used to acquire real-time sampled data of the voltage at the sending end and receiving end of the transmission line, as well as the operating parameters of the transmission line. The deviation analysis module is used to calculate the voltage deviation at the sending end and the voltage deviation at the receiving end based on real-time sampled data, and to determine the direction of voltage exceeding the limit. The threshold adaptive calculation module is used to dynamically calculate the high voltage trigger threshold and the low voltage trigger threshold based on the operating condition parameters, so as to obtain the bidirectional adaptive trigger threshold. The strategy matching module is used to match the corresponding voltage regulation strategy from the preset multi-source coordination strategy library based on the comparison result between the voltage over-limit direction and the bidirectional adaptive trigger threshold. The coordination control execution module is used to generate coordination control commands according to the matched voltage regulation strategy and send them to at least two voltage regulation devices. The self-learning optimization module is used to iteratively update the parameters of the bidirectional adaptive trigger threshold and the policy weights of the multi-source coordination policy library based on the adjustment result data.

[0041] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for bidirectional voltage adaptive regulation of transmission lines, characterized in that, Includes the following steps: S1: Acquire real-time sampling data of the voltage at the sending end and the voltage at the receiving end of the transmission line, and calculate the voltage deviation at the sending end and the voltage deviation at the receiving end based on the real-time sampling data; S2: Determine the voltage over-limit direction based on the voltage deviation at the sending end and the voltage deviation at the receiving end. The voltage over-limit direction includes the direction of voltage over-limit and the direction of voltage under-limit. S3: Based on the current operating parameters of the transmission line, dynamically calculate the high voltage trigger threshold and the low voltage trigger threshold to obtain the bidirectional adaptive trigger threshold. S4: Based on the comparison result between the voltage over-limit direction and the bidirectional adaptive trigger threshold, match the corresponding voltage regulation strategy from the preset multi-source coordination strategy library; S5: According to the matched voltage regulation strategy, generate coordinated control instructions for at least two types of voltage regulation equipment configured along the transmission line, and send them to each voltage regulation equipment to perform regulation operations. S6: Collect the adjustment result data of this adjustment operation, and input the adjustment result data into the preset self-learning optimization model to iteratively update the parameters of the bidirectional adaptive trigger threshold and the strategy weights of the multi-source coordination strategy library.

2. The bidirectional voltage adaptive regulation method for transmission lines as described in claim 1, characterized in that: In S2, when the voltage deviation at the sending end and the voltage deviation at the receiving end correspond to different voltage over-limit directions, the transmission line is divided into multiple segmented adjustment areas. A multi-source coordination strategy library is preset, and for each segmented adjustment area, a corresponding voltage adjustment strategy is matched in the multi-source coordination strategy library and sent to the voltage adjustment equipment in each segmented adjustment area to perform adjustment operations.

3. The bidirectional voltage adaptive regulation method for transmission lines as described in claim 1, characterized in that: In S3, the high voltage trigger threshold and low voltage trigger threshold are dynamically calculated, including obtaining the active load, reactive load, distributed power output status and line impedance parameters of the transmission line. The line voltage drop compensation is calculated based on the active and reactive loads, and the high voltage trigger threshold and low voltage trigger threshold are calculated based on the output status of the distributed power source and the line impedance parameters.

4. The bidirectional voltage adaptive regulation method for transmission lines as described in claim 1, characterized in that: In S4, the voltage regulation strategy includes: When the voltage exceeds the limit in the direction of high voltage, at least two of the following adjustment methods shall be selected in order of priority: lowering the on-load tap changer, connecting the shunt reactor, providing inductive reactive power output from the static var compensator, and disconnecting the capacitor bank; When the voltage exceeds the limit in the direction of low voltage, at least two of the following adjustment methods shall be selected in order of priority: raising the on-load tap changer, connecting the capacitor bank, providing capacitive reactive power output from the static var compensator, and increasing reactive power generation from distributed sources.

5. The bidirectional voltage adaptive regulation method for transmission lines as described in claim 1, characterized in that: In S5: Establish a digital twin model of the voltage regulation equipment for transmission lines. The digital twin model reflects the operating status and response characteristics of each voltage regulation device in real time. Before generating coordinated control commands for each voltage regulation device, the regulation effect is first simulated and verified in the digital twin model. When the simulation verification results show that the regulation effect does not meet the preset indicators, the voltage regulation strategy is rematched and the simulation verification is performed again until the regulation effect meets the preset indicators before the coordinated control command is issued.

6. The bidirectional voltage adaptive regulation method for transmission lines as described in claim 1, characterized in that: In step S6, the preset self-learning optimization model includes: Based on historical load time series data and meteorological data, the voltage trend in the future preset period is predicted, and a voltage prediction curve is obtained. Based on the voltage prediction curve, the bidirectional adaptive trigger threshold is feedforward corrected to obtain the predicted corrected bidirectional adaptive trigger threshold; when the real-time sampled data is close to the predicted corrected bidirectional adaptive trigger threshold, the corresponding voltage regulation strategy is triggered in advance.

7. The bidirectional voltage adaptive regulation method for transmission lines as described in claim 6, characterized in that: Predicting voltage trends over a predetermined time period, including: A voltage prediction model is constructed using long short-term memory networks or gated recurrent unit networks; Using historical load time-series data, historical voltage time-series data, and meteorological time-series data as input features, the system outputs a voltage prediction curve and prediction confidence interval for a preset future time period; and adaptively adjusts the safety margin of the bidirectional adaptive triggering threshold based on the prediction confidence interval.

8. The bidirectional voltage adaptive regulation method for transmission lines as described in claim 1, characterized in that: In step S6, the self-learning optimization model adopts the following update method: The evaluation indicators are the adjustment range of this adjustment operation, the convergence speed of the voltage deviation after adjustment, the number of equipment actions during the adjustment process, and the peak voltage fluctuation during the adjustment process. A multi-objective reward function is constructed based on the evaluation indicators, and the parameters of the bidirectional adaptive trigger threshold and the strategy weights of the multi-source coordination strategy library are updated online based on the multi-objective reward function.

9. The bidirectional voltage adaptive regulation method for transmission lines as described in claim 1, characterized in that: A bidirectional voltage adaptive regulation system for transmission lines is used, the system comprising: The data acquisition module is used to acquire real-time sampled data of the voltage at the sending end and receiving end of the transmission line, as well as the operating parameters of the transmission line. The deviation analysis module is used to calculate the voltage deviation at the sending end and the voltage deviation at the receiving end based on real-time sampled data, and to determine the direction of voltage exceeding the limit. The threshold adaptive calculation module is used to dynamically calculate the high voltage trigger threshold and the low voltage trigger threshold based on the operating condition parameters, so as to obtain the bidirectional adaptive trigger threshold. The strategy matching module is used to match the corresponding voltage regulation strategy from the preset multi-source coordination strategy library based on the comparison result between the voltage over-limit direction and the bidirectional adaptive trigger threshold. The coordination control execution module is used to generate coordination control commands according to the matched voltage regulation strategy and send them to at least two types of voltage regulation devices; the self-learning optimization module is used to iteratively update the parameters of the bidirectional adaptive trigger threshold and the strategy weights of the multi-source coordination strategy library based on the regulation result data.

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