Power transmission line dynamic load regulation and control method suitable for high-voltage power transmission system

Abstract

The invention relates to the technical field of power transmission line load regulation and control, in particular to a power transmission line dynamic load regulation and control method suitable for a high-voltage power transmission system. Determining the fluctuation coefficient of the current load of the power transmission line at each moment; obtaining the frequency of the oil field high-voltage power transmission system at each moment, and taking the frequency as the center frequency of a Butterworth filter at each moment; determining the order of a Butterworth filter at each moment by using the numerical value of the fluctuation coefficient, and optimizing the Butterworth filter in combination with the center frequency and the order; and carrying out harmonic extraction on the current signal at each moment by using the optimized Butterworth filter, and carrying out current compensation based on a harmonic component. The precision of power transmission line load regulation and control is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of power transmission line load regulation, in particular to a power transmission line dynamic load regulation method suitable for high-voltage power transmission systems. BACKGROUND

[0002] With the continuous expansion of oilfield oil and gas exploration production scale, the high-voltage power supply radius and power supply coverage of the oilfield power distribution and transmission network are also expanding, and the distribution of high-voltage power supply lines is complex, and the oilfield has higher requirements for power demand and power quality.

[0003] The oilfield power distribution and transmission network at the end is connected to many load fluctuation large pumping units, water injection pumps and oil stations, which account for more than 90% of the total power consumption of the oilfield power distribution and transmission network. The operation process of the pumping unit group presents regular pulsation, and at the same time, in order to maintain the stability of the formation pressure, the oilfield operates many high-power water injection pumps. In order to improve the stability and safety of the operation of the oil well pumping unit in the oilfield, a frequency converter is installed on the load side of the oil well transformer to drive the pumping unit, and the energy consumption of the frequency conversion driven pumping unit is relatively low. But the frequency converter is a nonlinear device, its harmonic spectrum is complex, and the conventional filter is difficult to effectively suppress the generation of harmonics, and the electromagnetic interference generated by harmonics will affect other interference protection devices in the oilfield power system, causing misoperation, and then interfering with the load regulation of the power transmission line, making it difficult to ensure the stable and safe transmission of power under the changing load and complex supply and demand environment, reducing the stability and reliability of the power grid. SUMMARY

[0004] In order to solve the above technical problems, the present application provides a power transmission line dynamic load regulation method suitable for high-voltage power transmission systems to solve the existing problems.

[0005] The power transmission line dynamic load regulation method suitable for high-voltage power transmission systems of the present application adopts the following technical scheme: One embodiment of the present application provides a power transmission line dynamic load regulation method suitable for high-voltage power transmission systems, which comprises the following steps: Collecting the current signal of the power transmission line of the oilfield power distribution and transmission network at each time; In the collected current signal, analyze the numerical difference and time difference between the nearest extreme value at each time and the nearest range difference between the adjacent time at each time, determine the fluctuation coefficient of the power transmission line current load at each time; Analyze the difference between the current effective value at each time and its adjacent time, determine the angular frequency of the power grid at each time; combine the angular frequency and the fluctuation coefficient to determine the frequency of the oilfield high-voltage power transmission system at each time, and take it as the center frequency of the Butterworth filter at each time; The numerical size of the fluctuation coefficient is used to determine the order of the Butterworth filter at each time, and the center frequency and the order are combined to optimize the Butterworth filter. The optimized Butterworth filter is used to extract harmonics of the current signal at each time, and the current compensation is performed based on the harmonic components.

[0006] In one embodiment, the determination of the fluctuation coefficient includes: For any time, the maximum value closest to the any time in the current signal is obtained, denoted as the first maximum value, and the maximum value closest to the adjacent time of the any time in the current signal is obtained, denoted as the second maximum value. The numerical difference and the time difference between the first maximum value and the second maximum value are calculated. Correspondingly, the minimum value closest to the any time in the current signal is obtained, denoted as the first minimum value, and the minimum value closest to the adjacent time of the any time in the current signal is obtained, denoted as the second minimum value. The numerical difference and the time difference between the first minimum value and the second minimum value are calculated. The numerical difference between the first maximum value and the second maximum value is weighted by the time difference between the first maximum value and the second maximum value to obtain a first weighted result. The numerical difference between the first minimum value and the second minimum value is weighted by the time difference between the first minimum value and the second minimum value to obtain a second weighted result. The fluctuation coefficient is positively correlated with the first weighted result and the second weighted result.

[0007] In one embodiment, the sum of the first weighted result and the second weighted result is calculated, and the fluctuation coefficient is the average of the sum of all adjacent times of the any time.

[0008] In one embodiment, the calculation of the numerical difference and the time difference between the first maximum value and the second maximum value includes: The absolute value of the difference between the first maximum value and the second maximum value is calculated as the numerical difference, and the absolute value of the difference between the corresponding time of the first maximum value and the corresponding time of the second maximum value is calculated as the time difference.

[0009] In one embodiment, the determination of the angular frequency of the power grid at each time includes: The cumulative sum of the current effective values of a preset number of adjacent times before each time is calculated, and the angular frequency of the power grid at each time is determined based on the cumulative sum at each time and the current effective value at each time.

[0010] In one embodiment, the angular frequency of the power grid at each time is expressed as: wherein, is the effective value of the current at time t-1, is the effective value of the current at time t-2, is the effective value of the current at time t, is the angular frequency of the power grid at time t, and cos() is the cosine function, is the cumulative sum.

[0011] In one embodiment, the frequency of the oilfield high-voltage power transmission system at each time is positively correlated with the angular frequency and negatively correlated with the fluctuation coefficient.

[0012] In one embodiment, the frequency of the oilfield high-voltage power transmission system at each time is expressed as: wherein, is the frequency of the oilfield high-voltage power transmission system at time t, is the fluctuation coefficient of the power transmission line current load at time t, is the angular frequency of the power grid at time t, is the constant pi.

[0013] In one embodiment, the number of orders of the Butterworth filter at each time is determined based on the numerical value of the fluctuation coefficient, including: If the fluctuation coefficient is greater than or equal to a preset threshold, the number of orders of the Butterworth filter is set to a first value, otherwise, the number of orders of the Butterworth filter is set to a second value, wherein the first value is greater than the second value.

[0014] In one embodiment, the current compensation based on the harmonic component includes: For each time, a compensation current with the same amplitude and opposite phase as the harmonic current component extracted from the power grid is input into the power grid based on the pulse width modulation technology, so as to complete the current compensation.

[0015] The present application has at least the following beneficial effects: The application determines the fluctuation coefficient of the power transmission line current load at each moment by analyzing the numerical difference and time difference between the extreme value closest to each moment and the extreme difference closest to the adjacent moment of each moment in the collected current signal; the determination of the fluctuation coefficient quantifies the fluctuation degree of the current load, which helps to identify the transient change and abnormal fluctuation of the load, improves the response speed of the high-voltage power transmission system to unstable working conditions, and enhances the accuracy of load regulation; the difference between the current effective value at each moment and its adjacent moment is analyzed to determine the angular frequency of the power grid at each moment; which helps to capture the frequency deviation of the power grid in real time and improves the frequency stability; in combination with the angular frequency and the fluctuation coefficient, the frequency of the oilfield high-voltage power transmission system at each moment is determined, and it is used as the center frequency of the Butterworth filter at each moment to ensure that the Butterworth filter can be optimized according to the current grid state, and the center frequency is dynamically adjusted when the frequency fluctuates to prevent harmonic amplification or distortion; the numerical size of the fluctuation coefficient is used to determine the order of the Butterworth filter at each moment, and the center frequency and the order are combined to optimize the Butterworth filter; dynamically setting the center frequency enables the Butterworth filter to adapt to the changes in the power grid, improves the pertinence and efficiency of harmonic extraction, and dynamically selects the order using the size of the fluctuation coefficient to enhance the frequency selectivity of the Butterworth filter; high-order filters provide steeper filtering characteristics when fluctuations are severe, and low-order filters reduce the computational burden under stable working conditions; the optimized Butterworth filter is used for harmonic extraction of the current signal at each moment, and current compensation is performed based on the harmonic components; the optimized Butterworth filter significantly improves the filtering performance and dynamic response characteristics, improves the accuracy of harmonic separation, reduces signal loss, enhances the robustness of the high-voltage power transmission system to load mutations, avoids the shortcomings of traditional fixed-parameter filters, and directly performs current compensation based on optimized filter harmonic extraction to improve the accuracy of load regulation, greatly improve power quality, improve the load capacity and voltage stability of the power transmission line, reduce voltage fluctuations and distortion, and ensure power purity. BRIEF DESCRIPTION OF DRAWINGS

[0016] In order to more clearly illustrate the technical solutions and advantages of the embodiments of the present application or the prior art, the drawings needed in the following embodiment or prior art description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and those skilled in the art can obtain other drawings according to these drawings without creating any inventive labor.

[0017] Figure 1 The step flow chart of the power transmission line dynamic load regulation method suitable for the high-voltage power transmission system provided by the present application is shown in the figure. Figure 2 The current compensation index relationship flow chart is shown in the figure. DETAILED DESCRIPTION

[0018] In order to further clarify the technical means and effects taken by the present application to achieve the predetermined object of the application, the specific implementation, structure, features and effects of the power transmission line dynamic load regulation method for high-voltage power transmission system according to the present application are described in detail below in combination with the drawings and preferred embodiments. In the following description, different "one embodiment" or "another embodiment" do not necessarily refer to the same embodiment. In addition, the specific features, structures or characteristics in one or more embodiments can be combined in any suitable form.

[0019] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

[0020] The specific scheme of the power transmission line dynamic load regulation method for high-voltage power transmission system provided by the present application is described in detail below in combination with the drawings.

[0021] The power transmission line dynamic load regulation method for high-voltage power transmission system provided by one embodiment of the present application, in particular, provides the following power transmission line dynamic load regulation method for high-voltage power transmission system, please refer to Figure 1 The method comprises the following steps: Step S001, collecting the current signal of the power transmission line of the oilfield power distribution transmission network at each time.

[0022] The oilfield power distribution transmission network is different from the ordinary power grid and has certain particularity. In general, the oilfield power distribution transmission network is located in a relatively remote geological location, has long power supply radius, complex equipment and harsh operating environment. In this embodiment, the oilfield information automatic acquisition system is used to obtain the current signal of the power transmission line of the oilfield power distribution transmission network at each time, and the acquisition frequency is 500Hz. The implementer can set it according to the actual situation, and this embodiment does not limit it. The oilfield information automatic acquisition system is a known technology, and the specific process is not described here.

[0023] Step S002, in the collected current signal, analyzing the numerical difference and time difference between the nearest extreme value at each time and the nearest range difference between the adjacent time at each time, to determine the fluctuation coefficient of the power transmission line current load at each time.

[0024] Because the operation of the pumping unit on the load side in the power distribution and transmission network of the oil field produces harmonic pollution, in general, harmonic suppression mainly adopts active harmonic suppression and passive harmonic suppression technology. The passive harmonic suppression technology absorbs harmonic current through the addition of harmonic filter equipment. In the current power transmission line of the oil field power grid, the APF (active power filter) technology is mostly used to filter the harmonic oscillation generated during the operation of the pumping unit in the oil field power grid. However, the APF needs to accurately obtain the harmonic and reactive current in the power grid in real time to control the power distribution and transmission line of the oil field.

[0025] The pumping unit drives the crank rod to make reciprocating motion through the motor, so that the horse head moves up and down to bring the underground oil to the ground. During the lifting and starting process of the horse head, the motor drives to work to pump oil; but during the lowering process of the horse head, the load becomes lighter, and the motor is basically in a free state. At this time, the pumping unit is in a reverse power generation state, and the frequency converter reversely transmits electric energy to the power grid. Due to the non-linear change characteristics, the current load curve of the power distribution and transmission line of the oil field is distorted, which greatly affects and interferes with the normal operation of other equipment in the power distribution and transmission network of the oil field.

[0026] In the power system, if there is no nonlinear load, the current signal of the transmission line should be in the form of sinusoidal current. However, due to the existence of nonlinear load in the power system, the harmonic current signal will be superimposed with the fundamental current signal to form the actual current signal of the power grid. In order to analyze the degree of interference of the harmonic current on the collected current signal in this embodiment, the collected current signal is first windowed. Since the up-and-down stroke period during the operation of the pumping unit is usually 12-15s, the length of the time window for windowing is set to 12s in this embodiment. The implementer can set it according to the actual situation, which is not limited in this embodiment.

[0027] Secondly, the fluctuation coefficient of the power transmission line current load at each time is calculated, which is specifically: For any time, the maximum value closest to the any time in the current signal is obtained, which is recorded as the first maximum value, and the maximum value closest to the adjacent time of the any time in the current signal is obtained, which is recorded as the second maximum value; The numerical difference and time difference between the first maximum value and the second maximum value are calculated. Correspondingly, the minimum value closest to the any time in the current signal is obtained, which is recorded as the first minimum value, and the minimum value closest to the adjacent time of the any time in the current signal is obtained, which is recorded as the second minimum value. The numerical difference and time difference between the first minimum value and the second minimum value are calculated. The numerical difference between the first maximum value and the second maximum value is weighted by the time difference between the first maximum value and the second maximum value to obtain the first weighted result. weighting the numerical difference between the first minimum value and the second minimum value with the time difference between the first minimum value and the second minimum value, to obtain a second weighting result; The fluctuation coefficient is positively correlated with the first weighting result and the second weighting result.

[0028] It should be noted that the difference represents the difference between two variables, which can be calculated in the form of absolute value, square, ratio, etc., and the present embodiment does not limit this.

[0029] The expression of the fluctuation coefficient of the power transmission line current load at each time in the present embodiment is: In the formula, is the fluctuation coefficient of the power transmission line current load at time t, is the number of adjacent time points of time t, in the present embodiment, the n time points before time t are taken as the adjacent time points of time t, and n=3, and the implementer can set it according to the actual situation, and the present embodiment does not limit this; is the time difference between the first maximum value and the second maximum value corresponding to time t and its i-th adjacent time point, is the absolute value of the difference between the first maximum value and the second maximum value corresponding to time t and its i-th adjacent time point, is the time difference between the first minimum value and the second minimum value corresponding to time t and its i-th adjacent time point, is the absolute value of the difference between the first minimum value and the second minimum value corresponding to time t and its i-th adjacent time point.

[0030] In the present embodiment, The calculation method of is as follows: the absolute value of the difference between the corresponding time of the first maximum value and the corresponding time of the second maximum value corresponding to time t and its i-th adjacent time point is calculated, denoted as the time sequence difference absolute value, and the ratio of the time sequence difference absolute value to the length of the set time window is taken as the time difference between the first maximum value and the second maximum value corresponding to time t and its i-th adjacent time point. Correspondingly, the calculation method of is based on the first minimum value and the second minimum value, and the same calculation method as that of is adopted to obtain the time difference between the first minimum value and the second minimum value corresponding to time t and its i-th adjacent time point.

[0031] ​​It should be understood that through the calculation of the fluctuation coefficient, the current load change at different time instants during the operation of the pumping unit can be analyzed. If the current waveform of the power transmission line is normal without distortion, the difference between the maximum and minimum values calculated at the sampling point positions at different time instants should be relatively small. On the contrary, if the power system has non-linear load, the current has harmonic distortion, the harmonic frequency is an integer multiple of the fundamental frequency, and the difference between the extreme values at different sampling points in the current signal is larger than that of the undistorted current waveform. During an up-down stroke cycle of the pumping unit during operation, if the extreme value difference at different sampling time point positions is too large, it indicates that the current waveform distortion is more serious, and the calculated fluctuation coefficient value of the power transmission line current load will also be relatively large.

[0032] In step S003, the difference between the current effective values at each time instant and its adjacent time instant is analyzed to determine the angular frequency of the power grid at each time instant. The frequency of the oilfield high-voltage power transmission system at each time instant is determined in combination with the angular frequency and the fluctuation coefficient, and is used as the center frequency of the Butterworth filter at each time instant.

[0033] The variable frequency pumping unit as a non-linear load generates components with integer multiples of the fundamental frequency in the power grid. Therefore, in the process of filtering the harmonic of the power transmission line load by the active power filter, real-time and accurate acquisition of the harmonic is an important prerequisite for harmonic suppression in the power transmission line load regulation process. The three-phase instantaneous reactive power detection theory is based on average power. At present, the p-q and method based on the three-phase instantaneous reactive power theory is commonly used. This method obtains the direct current component through the LPF low-pass filter, and then obtains the harmonic component by subtracting the direct current component from the original three-phase current in the transformed coordinate system. In practical applications, the Butterworth low-pass filter is often used for the LPF low-pass filter, but the order and center frequency of the Butterworth low-pass filter are crucial in the extraction of harmonic components. The order determines the decay rate of the filter, and the higher the order, the narrower the transition band of the filter, which can more accurately separate the fundamental frequency signal and the harmonic, especially when the harmonic is close to the main frequency. High-order filters are more effective in removing high-order harmonics and noise, but they increase the computational complexity and delay. The center frequency determines the frequency position at which the filter starts to attenuate the signal. Accurate center frequency setting ensures that the required low-frequency signal can be effectively extracted while removing unwanted high-frequency components. If the center frequency is not set properly, it may result in signal loss or inaccurate harmonic extraction. That is, the accurate selection of the order and center frequency of the Butterworth low-pass filter directly affects the accuracy and efficiency of the harmonic component extraction.

[0034] Therefore, in order to ensure the safety of the power transmission line load regulation of the oilfield high-voltage power transmission system, the present embodiment designs an optimal Butterworth filter in combination with the load variation law of the oil pumping unit, so as to detect and filter the harmonic components of the oilfield power transmission line.

[0035] Generally, the fundamental frequency provided by the power grid is f=50Hz, at which the current signal effective value is , is the angular frequency, that is . Since there are a large number of nonlinear loads in the oilfield high-voltage power transmission system, a large number of high-order harmonics and subharmonics exist in the oilfield power grid, which causes a large change in the power grid frequency obtained by the transmission line. Therefore, in order to track and calculate the power grid frequency of the oilfield high-voltage power transmission system, the power grid frequency of the oilfield high-voltage power transmission system at each time is calculated, specifically as follows: First, the cumulative sum of the current effective values of a preset number of adjacent time points before each time point is calculated, and based on the cumulative sum at each time point and the current effective value at each time point, the angular frequency of the power grid at each time point is determined. In the present embodiment, the preset number is set to 2, and the implementer can set it according to the actual situation, which is not limited in the present embodiment.

[0036] The calculation method of the angular frequency of the power grid at each time point is as follows: ; in the formula, is the current effective value at t-1, is the current effective value at t-2, is the current effective value at t, is the angular frequency of the power grid at t, cos() is the cosine function, is the cumulative sum.

[0037] Secondly, the frequency of the oilfield high-voltage power transmission system at each time point is positively correlated with the angular frequency and negatively correlated with the fluctuation coefficient, and the expression of the frequency of the oilfield high-voltage power transmission system at each time point is as follows: ; in the formula, is the frequency of the oilfield high-voltage power transmission system at t, is the fluctuation coefficient of the transmission line current load at t, is the angular frequency of the power grid at t, is the circular constant.

[0038] Since there are a large number of nonlinear loads in the oilfield high-voltage power transmission system, a large number of harmonics are superimposed, so the real-time frequency of the power grid changes. In order to accurately obtain the power grid frequency under the operating state of the nonlinear load, the present embodiment tracks and calculates the real-time frequency of the power grid based on the current fluctuation caused by the operation of the oilfield pumping unit, so as to obtain the real-time frequency of the power transmission system.

[0039] At t, the frequency of the oilfield high-voltage power transmission system is taken as the center frequency of the Butterworth filter.

[0040] Step S004, the numerical value of the fluctuation coefficient is used to determine the order of the Butterworth filter at each time, and the center frequency and the order are combined to optimize the Butterworth filter. The optimized Butterworth filter is used to extract the harmonic component of the current signal at each time, and the current compensation is based on the harmonic component.

[0041] In addition, the order of the Butterworth filter determines the real-time accuracy of harmonic detection and filtering in the power transmission line. The higher the order of the Butterworth filter, the higher the accuracy of harmonic filtering in the power transmission line, but it cannot achieve accurate tracking detection and calculation of the harmonic component of the power grid. In this embodiment, the order of the Butterworth filter is dynamically adjusted in combination with the fluctuation coefficient of the current load of the power transmission line. When the fluctuation coefficient of the current load of the power transmission line is larger, it indicates that the fluctuation change caused by the nonlinear load of the power grid is more obvious. At this time, in order to enhance the accuracy of harmonic detection, the order of the Butterworth filter should be set to a larger value. Therefore, this embodiment presets a threshold T. When the fluctuation coefficient of the current load of the power transmission line at time t is greater than or equal to the threshold T, it indicates that the fluctuation change caused by the nonlinear load of the power grid is more obvious. At this time, in order to reduce the error of harmonic detection, the order of the Butterworth filter is set to a first value N1. Otherwise, if the fluctuation coefficient of the current load of the power transmission line at time t is less than the threshold T, it indicates that the current load state is good. At this time, in order to ensure real-time tracking of the power grid load, the order of the Butterworth filter is set to a second value N2. The first value N1 is greater than the second value N2. By dynamically adjusting the order of the Butterworth filter, the Butterworth filter is optimized, thereby realizing real-time and accurate tracking of the harmonic component in the load of the power transmission line of the power grid.

[0042] In this embodiment, T=0.7, N1=4, and N2=2. The implementer can set them according to the actual situation, which is not limited in this embodiment.

[0043] For the current time t, the current signal in a time window is taken, the optimized Butterworth filter is used to extract the harmonic component of the current signal in the time window, and the PWM (Pulse-width Modulation) inverter is used to input a compensation current with the same amplitude and opposite phase as the detected harmonic current component into the power grid, so as to offset the interference of the harmonic current component on the safety of the power grid, and realize dynamic load regulation and control of the power transmission system. Figure 2

[0044] ​It should be noted that the above-mentioned order of the embodiments of the present application is only for description, and does not represent the advantages and disadvantages of the embodiments. And the above describes specific embodiments of the present specification. In addition, the processes depicted in the drawings do not necessarily require the specific order or continuous order shown to achieve the desired results. In some embodiments, multi-task processing and parallel processing are also possible or can be advantageous.

[0045] Each of the embodiments in the specification is described in a progressive manner, and the same or similar parts between the embodiments can be referred to each other. Each embodiment focuses on the difference from other embodiments.

[0046] The above-described embodiments are only used to illustrate the technical solutions of the present application, but not limit them; modifying the technical solutions described in the above embodiments, or equivalently replacing some technical features, does not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application, and should be included in the protection scope of the present application.

Claims

1. A method for dynamic load control of transmission lines in a high-voltage power transmission system, characterized in that: The method comprises the following steps: Collect the current signals of the transmission lines of the oilfield power distribution network at each moment; In the collected current signal, the numerical difference and time difference between the closest extreme value at each moment and the closest extreme difference at the adjacent moments are analyzed to determine the fluctuation coefficient of the transmission line current load at each moment; Analyze the difference between the effective value of the current at each moment and its adjacent moments to determine the angular frequency of the power grid at each moment; combine the angular frequency with the fluctuation coefficient to determine the frequency of the oil field high-voltage transmission system at each moment, and use it as the center frequency of the Butterworth filter at each moment; Determine the order of the Butterworth filter at each moment by using the numerical value of the fluctuation coefficient, and optimize the Butterworth filter by combining the center frequency and the order; The optimized Butterworth filter is used to extract the harmonics of the current signal at each moment, and current compensation is performed based on the harmonic components.

2. The method for dynamic load control of a transmission line applicable to a high-voltage power transmission system according to claim 1, characterized in that: Determination of the fluctuation coefficient includes: At any moment, the maximum value closest to the moment is obtained in the current signal, which is recorded as the first maximum value; the maximum value closest to the adjacent moment of the moment is obtained in the current signal, which is recorded as the second maximum value; Calculating a numerical difference and a time difference between the first maximum value and the second maximum value; Correspondingly, the minimum value closest to any moment is obtained in the current signal and recorded as the first minimum value, and the minimum value closest to the adjacent moment of any moment is obtained in the current signal and recorded as the second minimum value; Calculating a numerical difference and a time difference between the first minimum value and the second minimum value; weighting the numerical difference between the first maximum value and the second maximum value based on the time difference between the first maximum value and the second maximum value to obtain a first weighted result; weighting the numerical difference between the first minimum value and the second minimum value based on the time difference between the first minimum value and the second minimum value to obtain a second weighted result; The fluctuation coefficient is positively correlated with both the first weighted result and the second weighted result.

3. The method for dynamic load control of a transmission line applicable to a high-voltage power transmission system according to claim 2, characterized in that: The sum of the first weighted result and the second weighted result is calculated, and the fluctuation coefficient is the average of the sum of all adjacent moments of any moment.

4. The method for dynamic load control of a transmission line applicable to a high-voltage power transmission system according to claim 2, wherein: The calculating of the numerical difference and the time difference between the first maximum value and the second maximum value includes: The absolute value of the difference between the first maximum value and the second maximum value is calculated as the numerical difference, and the absolute value of the difference between the corresponding moment of the first maximum value and the corresponding moment of the second maximum value is calculated as the time difference.

5. The method for dynamic load control of a transmission line applicable to a high-voltage power transmission system according to claim 1, characterized in that: Determining the angular frequency of the power grid at each moment includes: The cumulative sum of the effective current values ​​of a preset number of adjacent moments before each moment is calculated, and the angular frequency of the power grid at each moment is determined based on the cumulative sum at each moment and the effective current value at each moment.

6. The method for dynamic load control of a transmission line applicable to a high-voltage power transmission system according to claim 5, characterized in that: The expression of the angular frequency of the power grid at each moment is: Where, is the effective value of the current at time t-1, is the effective value of the current at time t-2, is the effective value of the current at time t, is the angular frequency of the power grid at time t, cos() is the trigonometric cosine function, is the cumulative sum.

7. The method for dynamic load control of a transmission line applicable to a high-voltage power transmission system according to claim 1, characterized in that: The frequency of the oilfield high-voltage power transmission system at each moment is positively correlated with the angular frequency and negatively correlated with the fluctuation coefficient.

8. The method for dynamic load control of a transmission line in a high-voltage power transmission system according to claim 1, wherein: The frequency of the oilfield high-voltage power transmission system at each moment is expressed as follows: Where, is the frequency of the oilfield high-voltage transmission system at time t, is the fluctuation coefficient of the transmission line current load at time t, is the angular frequency of the power grid at time t, is pi.

9. The method for dynamic load control of a transmission line applicable to a high-voltage power transmission system according to claim 1, characterized in that: Determining the order of the Butterworth filter at each moment by using the numerical value of the fluctuation coefficient includes: If the fluctuation coefficient is greater than or equal to a preset threshold, the order of the Butterworth filter is set to a first value; otherwise, the order of the Butterworth filter is set to a second value, wherein the first value is greater than the second value.

10. The method for dynamic load control of a transmission line applicable to a high-voltage power transmission system according to claim 1, characterized in that: The current compensation based on harmonic components includes: At each moment, a compensation current with the same amplitude and opposite phase to the extracted harmonic current component is input into the transmission network based on the pulse width modulation technology to complete the current compensation.

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