Power grid voltage compensation method and system considering new energy fluctuation

Abstract

The invention discloses a power grid voltage compensation method and system considering new energy fluctuation, and relates to the technical field of power line optimization, and the method comprises the steps: calculating a voltage drop value of a node connected with new energy in a power line; according to the voltage drop value, with the minimum total voltage amplitude loss of the power line as the target, reactive power compensation amount is calculated; establishing a first optimal configuration model for installing a reactive power compensation device, a series capacitor and an energy storage device on the power line; establishing a second optimal configuration model for installing a reactive power compensation device and an energy storage device on the power line; and solving the first optimal configuration model and the second optimal configuration model according to the reactive compensation amount, and generating a compensation configuration scheme of the power grid voltage. According to the embodiment of the invention, the reactive power compensation device, the series capacitor and the energy storage device can be combined to improve the voltage quality of a regional power grid, and meanwhile, the voltage drop of a power line is regulated and controlled in time.

Description

Technical Field

[0001] The present invention relates to the technical field of power line optimization, and particularly to a power grid voltage compensation method and system considering new energy fluctuations. Background Art

[0002] The access of distributed new energy in the power system introduces stronger fluctuations on the load side. At the same time, new energy has the risk of low-voltage and high-voltage disconnection from the grid. Voltage fluctuations caused by load fluctuations or partial new energy faults will affect the voltage quality of the system, and may even cause nearby new energy units to disconnect from the grid, resulting in a concentrated disconnection accident.

[0003] Voltage compensation is an important measure to improve the system voltage distribution and power quality. In the existing research on voltage compensation, most only consider using reactive power compensation devices such as capacitors. However, when the new energy fluctuates greatly, the capacity of the required reactive power compensation device will increase rapidly, and the requirements for equipment performance are relatively high. Summary of the Invention

[0004] The embodiments of the present invention provide a power grid voltage compensation method and system considering new energy fluctuations, which can combine reactive power compensation devices, series capacitors and energy storage devices to improve the voltage quality of the regional power grid while timely regulating the voltage drop of the power line.

[0005] The embodiments of the present invention provide a power grid voltage compensation method considering new energy fluctuations, including: Calculating the voltage drop value of the nodes accessing new energy in the power line; According to the voltage drop value, taking the minimum total voltage amplitude loss of the power line as the target, calculating the reactive power compensation amount; Establishing a first optimization configuration model for installing reactive power compensation devices, series capacitors and energy storage devices on the power line; Establishing a second optimization configuration model for installing reactive power compensation devices and energy storage devices on the power line; According to the reactive power compensation amount, solving the first optimization configuration model and the second optimization configuration model to generate a compensation configuration scheme for the power grid voltage.

[0006] As an improvement of the above solution, the calculating the voltage drop value of the nodes accessing new energy in the power line includes: Dividing the voltage drop vector at both ends of the power line into a longitudinal component and a transverse component; one end of the two ends of the power line is a first node accessing new energy, and the other end is a second node connected to the first node; According to the transverse component and the voltage phase angle difference at both ends of the power line, calculating the voltage drop value caused by the active power fluctuation of new energy.

[0007] As an improvement of the above solution, dividing the voltage drop vectors at both ends of the power line into longitudinal components and transverse components includes: Obtain the voltage drop vectors at both ends of the power line ; the flow direction of the power line is from the first node i to the second node j; wherein, is the longitudinal component; is the transverse component; is the active power flowing from the first node i to the second node j; is the resistance of the power line; is the reactive power flowing from the first node i to the second node j; is the reactance of the power line; is the voltage amplitude of the second node j.

[0008] As an improvement of the above solution, calculating the voltage drop value caused by the fluctuation of new energy active power according to the transverse component and the voltage phase angle difference at both ends of the power line includes: Obtain the voltage phase angle difference between the first node i and the second node j of the power line ; Through Calculate the voltage drop value caused by the fluctuation of new energy active power; wherein, is the voltage amplitude of the first node i.

[0009] As an improvement of the above solution, calculating the reactive power compensation amount with the lowest total voltage amplitude loss as the goal according to the voltage drop value includes: Construct a scenario where the reactive power compensation completely cancels the voltage drop value, and obtain the expression of the lowest total voltage amplitude loss according to the scenario; Solve the expression of the lowest total voltage amplitude loss to obtain the required reactive power compensation amount.

[0010] As an improvement of the above solution, establishing the first optimization configuration model for installing reactive power compensation devices, series capacitors and energy storage devices on the power line includes: Through Establish the first objective function; Through Establish the first constraint condition; Through Establish the second constraint condition; Through Establish the third constraint condition; According to the first objective function, the first constraint condition, the second constraint condition and the third constraint condition, establish the first optimization configuration model; wherein, is the capacitance of the series capacitor, is the capacitance of the reactive power compensation device, is the rated power of the energy storage device; , , are the configuration costs of the series capacitor, the reactive power compensation device, and the energy storage device respectively; is the angular frequency; is the maximum fluctuation of the active power; is the maximum fluctuation of the reactive power; is the reactance of the power line; and are the voltage amplitudes of the two ends of the power line respectively.

[0011] As an improvement to the above solution, the second optimization configuration model for installing a reactive power compensation device and an energy storage device on the power line includes: By establish a second objective function; By establish a fourth constraint condition; By establish a fifth constraint condition; According to the second objective function, the fourth constraint condition, and the fifth constraint condition, establish a second optimization configuration model; Wherein, is the capacitance of the reactive power compensation device, is the rated power of the energy storage device; , are the configuration costs of the reactive power compensation device and the energy storage device respectively; is the angular frequency; is the maximum fluctuation of the active power; is the maximum fluctuation of the reactive power; is the reactance of the power line; and are the voltage amplitudes of the two ends of the power line respectively.

[0012] As an improvement to the above solution, the method for solving the first optimization configuration model and the second optimization configuration model according to the reactive power compensation amount to generate a compensation configuration scheme for the grid voltage includes: Input the reactive power compensation amount into the first optimization configuration model and the second optimization configuration model; Use the nonlinear programming algorithm to solve the first optimization configuration model and the second optimization configuration model respectively to obtain a first objective value and a second objective value; Generate a compensation configuration scheme for the grid voltage according to the optimization configuration model corresponding to the smaller value of the first objective value and the second objective value.

[0013] As an improvement of the above solution, using the nonlinear programming algorithm to solve the first optimization configuration model and the second optimization configuration model respectively to obtain the first target value and the second target value includes: Select the initial parameter values of the first optimization configuration model and the second optimization configuration model; the initial parameter values include the initial capacitance value of the reactive power compensation device, the initial capacitance value of the series capacitor, the initial power value of the energy storage device, and the voltage amplitudes at both ends of the power line; Adopt the nonlinear programming algorithm to solve the first optimization configuration model and the second optimization configuration model according to the initial parameter values, and obtain the first target value and the second target value respectively.

[0014] An embodiment of the present invention further provides a power grid voltage compensation system considering new energy fluctuations, including: A voltage drop value calculation module for calculating the voltage drop value of the node where new energy is connected in the power line; A reactive power compensation amount calculation module for calculating the reactive power compensation amount with the lowest total voltage amplitude loss of the power line as the target according to the voltage drop value; A first model establishment module for establishing a first optimization configuration model of installing a reactive power compensation device, a series capacitor, and an energy storage device on the power line; A second model establishment module for establishing a second optimization configuration model of installing a reactive power compensation device and an energy storage device on the power line; A compensation scheme generation module for solving the first optimization configuration model and the second optimization configuration model according to the reactive power compensation amount and generating a compensation configuration scheme for the power grid voltage.

[0015] Compared with the prior art, a power grid voltage compensation method and system considering new energy fluctuations disclosed by the present invention calculate the voltage drop value of the node where new energy is connected in the power line; calculate the reactive power compensation amount with the lowest total voltage amplitude loss of the power line as the target according to the voltage drop value; establish a first optimization configuration model of installing a reactive power compensation device, a series capacitor, and an energy storage device on the power line; establish a second optimization configuration model of installing a reactive power compensation device and an energy storage device on the power line; solve the first optimization configuration model and the second optimization configuration model according to the reactive power compensation amount and generate a compensation configuration scheme for the power grid voltage. By adopting the embodiment of the present invention, the optimal configuration scheme can be selected from the combination of the reactive power compensation device, the series capacitor, and the energy storage device to adjust the system voltage, fully considering the principle of hierarchical and zonal reactive power compensation and local balance, and being applicable to the situation of large-scale access of distributed new energy, with both economy and practicability. Description of the Drawings

[0016] Figure 1It is a schematic diagram of the steps of a grid voltage compensation method considering the fluctuation of new energy provided by an embodiment of the present invention; Figure 2 It is a structural schematic diagram of an IEEE nine-node power system provided by an embodiment of the present invention; Figure 3 is a reactive compensation amount curve diagram provided by an embodiment of the present invention; Figure 4 It is a structural schematic diagram of a grid voltage compensation system taking into account fluctuations of renewable energy provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0017] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0018] In the description of the specification and claims, it is to be understood that the terms first, second, etc. in the specification and claims are only used for the purpose of describing the same technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated, nor necessarily describing the order or time sequence. The terms are interchangeable where appropriate. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features.

[0019] Photovoltaic, wind power and other new energy power stations adjust their output through grid-connected inverter control, and the power factor can usually reach above 0.98, so the impact of new energy fluctuations is mainly reflected in active power. In addition to affecting the system frequency, active power fluctuations in the power system may also cause system voltage abnormalities or even collapse.

[0020] Based on the problem that the voltage compensation method of only configuring reactive power compensation devices in the prior art cannot adapt well to the fluctuation of new energy, please refer to Figure 1 , the embodiment of the present invention provides a grid voltage compensation method considering the fluctuation of new energy, which is specifically performed through steps S1 to S5: S1. Calculate the voltage drop value of the node connected to the new energy in the power line.

[0021] S2. According to the voltage drop value, the reactive power compensation amount is calculated with the goal of minimizing the total voltage amplitude loss of the power line.

[0022] S3. Establish a first optimization configuration model by installing reactive power compensation devices, series capacitors and energy storage devices on the power lines.

[0023] S4. Establish a second optimal configuration model for installing reactive power compensation devices and energy storage devices on the power line.

[0024] S5. Solve the first optimal configuration model and the second optimal configuration model according to the reactive power compensation amount to generate a compensation configuration plan for the grid voltage.

[0025] In the embodiments of the present invention, two optimal configuration models are established, which can flexibly select the optimal compensation configuration plan according to the actual situation of the power line to meet the voltage compensation requirements under different grid scenarios. By installing reactive power compensation devices on the power line, the reactive power can be quickly adjusted; installing energy storage devices can effectively suppress part of the active power fluctuations; installing series capacitors can also reduce the line reactance; adopting the embodiments of the present invention can not only reduce the impact of new energy fluctuations on the power line, but also the energy storage device and the series capacitor can effectively reduce the configuration capacity of the required reactive power compensation device, improving the economy of the line.

[0026] In the above solution, the optimal configuration plan can be selected from the combination of reactive power compensation devices, series capacitors and energy storage devices to adjust the system voltage, fully considering the principles of hierarchical and zonal reactive power compensation and local balance, and being applicable to the situation of large-scale access of distributed new energy, with both economy and practicability.

[0027] As a preferred implementation manner, in step S1, calculate the voltage drop value of the nodes accessing new energy in the power line, which is executed through steps S11 - S12: S11. Divide the voltage drop vector at both ends of the power line into a longitudinal component and a transverse component; one end of the two ends of the power line is the first node accessing new energy, and the other end is the second node connected to the first node; S12. Calculate the voltage drop value caused by the active power fluctuation of new energy according to the transverse component and the voltage phase angle difference at both ends of the power line.

[0028] It should be noted that the voltage drop vector is usually in a complex form. After decomposing it into a longitudinal component and a transverse component, the complex vector operation is transformed into a relatively simple real number operation, which is more convenient for subsequent calculation and analysis. In the power system, the longitudinal component is mainly related to the active power and reactive power, and the transverse component is related to the voltage phase angle. This decomposition can clearly show the relationship between various physical quantities.

[0029] It should also be noted that in the power grid at the regional regulation level, the line reactance is usually much larger than the line resistance. Therefore, the active power fluctuation of new energy mainly affects the transverse component of the line voltage drop.

[0030] Further, preferably, step S11 of dividing the voltage drop vector at both ends of the power line into longitudinal and transverse components includes: Obtain the voltage drop vector at both ends of the power line ; the direction of the power line is from the first node i to the second node j; wherein, is the longitudinal component; is the transverse component; is the active power flowing from the first node i to the second node j; is the resistance of the power line; is the reactive power flowing from the first node i to the second node j; is the reactance of the power line; is the voltage amplitude of the second node j.

[0031] It should be noted that in the embodiments of the present invention, the two ends of the power line are respectively the first node and the second node. A new energy unit is introduced at the first node, and the power flow direction is from the first node to the second node. It can also be expressed as , and the voltage drop vector is based on as the reference vector.

[0032] Furthermore, preferably, step S12 of calculating the voltage drop value caused by the fluctuation of the new energy active power according to the transverse component and the voltage phase angle difference at both ends of the power line includes: Obtain the voltage phase angle difference between the first node i and the second node j of the power line ; Through calculate the voltage drop value caused by the fluctuation of the new energy active power; wherein, is the voltage amplitude of the first node i.

[0033] According to , it can be seen that when the line reactance X is much larger than the line resistance R, the fluctuation of the new energy active power will mainly affect the transverse component of the line voltage drop.

[0034] In the embodiments of the present invention, the transverse component is re-expressed. Since the voltage phase angle difference between the two ends of the regional power grid line is usually small, by approximately calculate the cosine value of the voltage phase angle difference , and retain the quadratic term of its Maclaurin formula for the cosine function during calculation to obtain . Then substitute to be able to obtain the voltage drop value caused by the fluctuation of the new energy active power . .

[0035] As a preferred embodiment, step S2, according to the voltage drop value, with the goal of minimizing the total voltage amplitude loss, calculates the reactive power compensation amount, including: Construct a scenario where the reactive power compensation completely cancels out the voltage drop value, and obtain the expression of the lowest total voltage amplitude loss according to the scenario; Solve the expression of the lowest total voltage amplitude loss to obtain the required reactive power compensation amount.

[0036] Exemplarily, the expression of the lowest total voltage amplitude loss is ; By solving the above formula, the required reactive power compensation amount is .

[0037] Based on the calculation of the reactive power compensation amount, it can be seen that for the voltage change caused by new energy fluctuations, if the voltage drop is suppressed by reactive power compensation, the required reactive power compensation amount is proportional to the square of the active power change amount and the line reactance size, and inversely proportional to the amplitude of the node voltages at both ends of the line. Therefore, when the absolute value of new energy fluctuations is not large, it is more economical to regulate the voltage through reactive power compensation devices. However, when the new energy fluctuations are large, according to the square relationship between the reactive power compensation amount and the active power fluctuation amount, the required capacity of the reactive power compensation device will increase rapidly. Directly adopting a high-capacity reactive power compensation device may result in a redundant configuration and low configuration economy.

[0038] As a preferred embodiment, step S3, establishes a first optimization configuration model for installing reactive power compensation devices, series capacitors, and energy storage devices on the power line, including: By Establish a first objective function; By Establish a first constraint condition; By Establish a second constraint condition; By Establish a third constraint condition; According to the first objective function, the first constraint condition, the second constraint condition, and the third constraint condition, establish a first optimization configuration model; Among them, is the capacitance of the series capacitor, is the capacitance of the reactive power compensation device, is the rated power of the energy storage device; , , are the configuration costs of the series capacitor, the reactive power compensation device, and the energy storage device respectively; is the angular frequency; is the maximum active power fluctuation amount; is the maximum reactive power fluctuation amount; is the reactance of the power line; and are the voltage amplitudes of the nodes at both ends of the power line, respectively.

[0039] In the first optimization configuration model, on the basis of installing a reactive power compensation device in the existing technology, a scheme of additionally installing a series capacitor and an energy storage device is also given. The energy storage device can suppress part of the active power fluctuation, thereby effectively reducing the configuration capacity of the required reactive power compensation device and realizing more economical system voltage regulation; installing a series capacitor on the line can reduce the line impedance and reduce the configuration capacity of the reactive power compensation device from another perspective.

[0040] It should be noted that in the embodiments of the present invention, 、 and can all be 0, indicating that the corresponding device is not configured.

[0041] As a preferred embodiment, step S4: Establish a second optimization configuration model for installing a reactive power compensation device and an energy storage device on the power line, including: Establish a second objective function through ; Establish a fourth constraint condition through ; Establish a fifth constraint condition through ; Establish a second optimization configuration model according to the second objective function, the fourth constraint condition and the fifth constraint condition; wherein, is the capacitance of the reactive power compensation device, is the rated power of the energy storage device; 、 are the configuration costs of the reactive power compensation device and the energy storage device, respectively; is the angular frequency; is the maximum active power fluctuation; is the maximum reactive power fluctuation; is the reactance of the power line; and are the voltage amplitudes of the nodes at both ends of the power line, respectively.

[0042] Considering that in some power grid scenarios, the demand for reactive power compensation is small, and in the case where the series capacitor is not configured, the first optimization configuration model cannot represent the limit case. The embodiments of the present invention also provide a second optimization configuration model. The first optimization configuration model and the second optimization configuration model can effectively and fully utilize the advantages of each device to achieve the optimal voltage compensation effect.

[0043] As a preferred embodiment, step S5, according to the reactive power compensation amount, solving the first optimization configuration model and the second optimization configuration model to generate a compensation configuration scheme for the grid voltage, includes: Inputting the reactive power compensation amount into the first optimization configuration model and the second optimization configuration model; Using a nonlinear programming algorithm to solve the first optimization configuration model and the second optimization configuration model respectively to obtain a first objective value and a second objective value; Generating a compensation configuration scheme for the grid voltage according to the optimization configuration model corresponding to the smaller value among the first objective value and the second objective value.

[0044] It should be noted that the nonlinear programming algorithm is applicable to solving such optimization problems that contain nonlinear objective functions and constraint conditions. Through this algorithm, the optimal solution of the objective function can be found under various constraint conditions, that is, the first objective value corresponding to the first optimization configuration model and the second objective value corresponding to the second optimization configuration model are obtained.

[0045] Further preferably, the using a nonlinear programming algorithm to solve the first optimization configuration model and the second optimization configuration model respectively to obtain a first objective value and a second objective value includes: Selecting the initial parameter values of the first optimization configuration model and the second optimization configuration model; the initial parameter values include the initial capacitance value of the reactive power compensation device, the initial capacitance value of the series capacitor, the initial power value of the energy storage device, and the voltage amplitudes at both ends of the power line; Using a nonlinear programming algorithm to solve the first optimization configuration model and the second optimization configuration model according to the initial parameter values to obtain a first objective value and a second objective value respectively.

[0046] In the nonlinear programming algorithm, the values of variables will be continuously updated through iterative calculations to make the objective function gradually converge. Therefore, initial values need to be selected for each variable.

[0047] Exemplarily, each physical quantity adopts a per-unit value, the initial capacitance value of the reactive power compensation device is , the initial power value of the energy storage device is 0, the initial capacitance value of the series capacitor is , and the voltage amplitudes at both ends of the power line are both constant 1.

[0048] In a preferred embodiment, the embodiment of the present invention is applied to the grid voltage compensation process of the IEEE9-bus power system as Figure 2 shown. In Figure 2Among them, the numbers represent the node numbers, and G represents the power supply node. A new energy unit is connected to node 9, and the maximum fluctuations in active power and reactive power caused by the new energy and load at this node are 142 MW and 25 Mvar respectively.

[0049] Considering the voltage stability under N-1 fault conditions, through static security analysis, it can be obtained that when the branch 4-9 is opened, the voltage drop at node 9 is the largest. In this scenario, further considering the voltage drop caused by the power fluctuation at node 9, the voltage at node 9 is restored to the initial level through voltage compensation.

[0050] If only a reactive power compensation device is installed at node 9 to regulate the voltage as in the prior art, the reactive power compensation amount as shown by the solid line will be obtained. This reactive power compensation amount can restore the voltage at node 9 to the initial level. Figure 3 As shown by the solid line, this reactive power compensation amount can restore the voltage at node 9 to the initial level.

[0051] It can be seen that the system voltage change caused by new energy fluctuations can be compensated through reactive power compensation, and through the least squares method to fit the curve analysis, it can be obtained that there is approximately a quadratic function relationship between the required reactive power compensation amount and the active power fluctuation amount.

[0052] Furthermore, the root mean square error index is used to measure the error of curve fitting. According to The calculated root mean square error is 1.0547; where s is the sample point number; u(s) is the function to be fitted; y(s) is the fitted function; Ns is the number of sample points. The dimension of the root mean square error is the same as that of the original function. Comparing it with the average value of the reactive power compensation amount shown by the solid line in Figure 2 The relative error is 1.32%, and this fitting error is very small.

[0053] In the first optimization configuration model established by the method described in the embodiment of the present invention, the installation positions of the series capacitors are branch 4-9 and branch 8-9. Let c s =c p =1.05×10 5 yuan / μF, c b =1.93×10 6 yuan / MVA, ω = 314.16 rad / s, and the first objective function is established. Solving the first optimization configuration model, the configured capacitance of the reactive power compensation device is 3.0×10-3F, the configured capacitance of the series capacitor is 7.74×10-5F, the configured capacitance of the energy storage device is 0, and the total cost is 3.301×108 yuan.

[0054] In addition, a second optimization configuration model is established and solved, and the configured capacitance of the reactive power compensation device is 3.6×10-3F, the configured capacitance of the energy storage device is 11.5 MW, and the total cost is 3.988×108 yuan.

[0055] After comparing the solution results of the two models, the configuration scheme corresponding to the first optimization model is adopted as the compensation configuration scheme for the grid voltage. That is, series capacitors with a configured capacity of 7.74×10-5F are installed on branch 4-9 and branch 8-9, and a reactive power compensation device with a capacitance of 3.0×10-3F is installed at node 9.

[0056] Figure 3 The wide dashed line of shows the reactive power compensation amount required to cope with voltage drop under the compensation configuration scheme given in the embodiment of the present invention. It can be seen that by adopting the embodiment of the present invention, the configured capacity of the reactive power compensation device can be effectively reduced at a lower cost.

[0057] By using a grid voltage compensation method considering new energy fluctuations provided by the embodiment of the present invention, an optimal configuration scheme can be selected from the combination of reactive power compensation devices, series capacitors and energy storage devices to adjust the system voltage, fully considering the principles of hierarchical and zonal reactive power compensation and local balance, and being applicable to the situation of large-scale access of distributed new energy, with both economy and practicality.

[0058] The embodiment of the present invention provides a grid voltage compensation system considering new energy fluctuations. Please refer to Figure 4 , the grid voltage compensation system considering new energy fluctuations includes a voltage drop value calculation module 11, a reactive power compensation amount calculation module 12, a first model establishment module 13, a second model establishment module 14 and a compensation scheme generation module 15, where: The voltage drop value calculation module 11 is used to calculate the voltage drop value of the node accessing new energy in the power line; The reactive power compensation amount calculation module 12 is used to calculate the reactive power compensation amount with the lowest total voltage amplitude loss of the power line as the target according to the voltage drop value; The first model establishment module 13 is used to establish a first optimal configuration model for installing reactive power compensation devices, series capacitors and energy storage devices on the power line; The second model establishment module 14 is used to establish a second optimal configuration model for installing reactive power compensation devices and energy storage devices on the power line; The compensation scheme generation module 15 is used to solve the first optimal configuration model and the second optimal configuration model according to the reactive power compensation amount, and generate a compensation configuration scheme for the grid voltage.

[0059] As a preferred implementation manner, the voltage drop value calculation module 11 includes: A vector division unit, configured to divide the voltage drop vector at both ends of the power line into a longitudinal component and a transverse component; one end of the two ends of the power line is a first node accessing new energy, and the other end is a second node connected to the first node; A voltage drop calculation unit, configured to calculate a voltage drop value caused by new energy active power fluctuations according to the transverse component and the voltage phase angle difference at both ends of a power line.

[0060] Further, preferably, the vector division unit is specifically configured to: Obtain the voltage drop vector at both ends of the power line ; the flow direction of the power line is from the first node i to the second node j; Wherein, is the longitudinal component; is the transverse component; is the active power flowing from the first node i to the second node j; is the resistance of the power line; is the reactive power flowing from the first node i to the second node j; is the reactance of the power line; is the voltage amplitude of the second node j.

[0061] Even further, preferably, the voltage drop calculation unit is configured to: Obtain the voltage phase angle difference between the first node i and the second node j of the power line ; Through Calculate the voltage drop value caused by new energy active power fluctuations; wherein, is the voltage amplitude of the first node i.

[0062] As a preferred implementation manner, the reactive power compensation amount calculation module 12 is specifically configured to: Construct a scenario where the reactive power compensation completely cancels the voltage drop value, and obtain the expression of the lowest total voltage amplitude loss according to the scenario; Solve the expression of the lowest total voltage amplitude loss to obtain the required reactive power compensation amount.

[0063] As a preferred implementation manner, the first model establishment module 13 is specifically configured to: Through Establish a first objective function; Through Establish a first constraint condition; Through Establish a second constraint condition; Through Establish a third constraint condition; According to the first objective function, the first constraint condition, the second constraint condition, and the third constraint condition, establish a first optimal configuration model; Wherein, is the capacitance of the series capacitor, is the capacitance of the reactive power compensation device, is the rated power of the energy storage device; , , are the configuration costs of the series capacitor, reactive power compensation device, and energy storage device respectively; is the angular frequency; is the maximum fluctuation of active power; is the maximum fluctuation of reactive power; is the reactance of the power line; and are the voltage amplitudes at both ends of the power line node respectively.

[0064] As a preferred embodiment, the second model establishment module 14 is specifically configured to: Establish a second objective function through ; Establish a fourth constraint condition through ; Establish a fifth constraint condition through ; Establish a second optimal configuration model according to the second objective function, the fourth constraint condition, and the fifth constraint condition; Wherein, is the capacitance of the reactive power compensation device, is the rated power of the energy storage device; , are the configuration costs of the reactive power compensation device and the energy storage device respectively; is the angular frequency; is the maximum fluctuation of active power; is the maximum fluctuation of reactive power; is the reactance of the power line; and are the voltage amplitudes at both ends of the power line node respectively.

[0065] As a preferred embodiment, the compensation scheme generation module 15 includes: A parameter substitution unit for inputting the reactive power compensation amount into the first optimal configuration model and the second optimal configuration model; A model solving unit for using a nonlinear programming algorithm to solve the first optimal configuration model and the second optimal configuration model respectively to obtain a first objective value and a second objective value; A scheme generation unit for generating a compensation configuration scheme for the grid voltage according to the optimal configuration model corresponding to the smaller value of the first objective value and the second objective value.

[0066] Further, preferably, the model solving unit is specifically configured to: Select the initial parameter values of the first optimized configuration model and the second optimized configuration model; the initial parameter values include the initial capacitance value of the reactive power compensation device, the initial capacitance value of the series capacitor, the initial power value of the energy storage device, and the voltage amplitudes at both ends of the power line. Adopt a nonlinear programming algorithm to solve the first optimized configuration model and the second optimized configuration model according to the initial parameter values, and obtain a first objective value and a second objective value respectively.

[0067] By using a power grid voltage compensation system considering new energy fluctuations provided by an embodiment of the present invention, an optimal configuration scheme can be selected from the combination of a reactive power compensation device, a series capacitor, and an energy storage device to adjust the system voltage, fully considering the principles of hierarchical and zonal reactive power compensation and local balance, and being applicable to the scenario of large-scale access of distributed new energy, and having both economy and practicability.

[0068] Those of ordinary skill in the art can understand that all or part of the processes in the methods of the above embodiments can be completed by instructing relevant hardware through a computer program. The program can be stored in a computer-readable storage medium. When the program is executed, it can include the processes of the embodiments of the above methods. Among them, the storage medium can be a magnetic disk, an optical disk, a read-only memory (ROM), or a random access memory (RAM), etc.

[0069] The above is the preferred embodiment of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements are also regarded as the protection scope of the present invention.

Claims

1. A method for compensating grid voltage considering the fluctuations of new energy, characterized in that Including: Calculating the voltage drop value of the node accessing new energy in the power line; Calculating the reactive power compensation amount with the lowest total voltage amplitude loss of the power line as the goal according to the voltage drop value; Establishing a first optimization configuration model for installing reactive power compensation devices, series capacitors and energy storage devices on the power line; Establishing a second optimization configuration model for installing reactive power compensation devices and energy storage devices on the power line; Solving the first optimization configuration model and the second optimization configuration model according to the reactive power compensation amount to generate a compensation configuration scheme for the grid voltage.

2. The grid voltage compensation method considering new energy fluctuations according to claim 1, characterized in that, The calculating the voltage drop value of the node accessing new energy in the power line includes: Dividing the voltage drop vector at both ends of the power line into longitudinal components and transverse components; one end of the two ends of the power line is the first node accessing new energy, and the other end is the second node connected to the first node; Calculating the voltage drop value caused by the fluctuation of new energy active power according to the transverse component and the voltage phase angle difference at both ends of the power line.

3. A method for compensating grid voltage considering new energy fluctuations as described in claim 2, characterized in that The dividing the voltage drop vector at both ends of the power line into longitudinal components and transverse components includes: Obtain the voltage drop vectors at both ends of the power line ; The flow direction of the power line is from the first node i to the second node j; Among them, is the longitudinal component; is the transverse component; is the active power flowing from the first node i to the second node j; is the resistance of the power line; is the reactive power flowing from the first node i to the second node j; is the reactance of the power line; is the voltage amplitude of the second node j.

4. A method for compensating grid voltage considering new energy fluctuations according to claim 3, characterized in that, The calculating the voltage drop value caused by the fluctuation of new energy active power according to the transverse component and the voltage phase angle difference at both ends of the power line includes: Obtain the voltage phase angle difference between the first node i and the second node j of the power line ; By calculating the voltage drop value caused by the active power fluctuation of new energy; wherein, is the voltage amplitude of the first node i.

5. A method for compensating grid voltage considering new energy fluctuations according to claim 1, characterized in that, The calculating the reactive power compensation amount with the lowest total voltage amplitude loss as the goal according to the voltage drop value includes: Constructing a scenario where the reactive power compensation completely offsets the voltage drop value, and obtaining the expression of the lowest total voltage amplitude loss according to the scenario; Solving the expression of the lowest total voltage amplitude loss to obtain the required reactive power compensation amount.

6. A method for compensating grid voltage considering new energy fluctuations as described in claim 1, characterized in that, The establishing a first optimization configuration model for installing reactive power compensation devices, series capacitors and energy storage devices on the power line includes: By establishing a first objective function; By establishing a first constraint condition; By establishing a second constraint condition; By establishing a third constraint condition; Establishing a first optimization configuration model according to the first objective function, the first constraint condition, the second constraint condition and the third constraint condition; Among them, is the capacitance of the series capacitor, is the capacitance of the reactive power compensation device, is the rated power of the energy storage device; 、 、 are the configuration costs of the series capacitor, the reactive power compensation device and the energy storage device respectively; is the angular frequency; is the maximum fluctuation of the active power; is the maximum fluctuation of the reactive power; is the reactance of the power line; and are the voltage amplitudes of the nodes at both ends of the power line respectively.

7. A method for compensating grid voltage considering new energy fluctuations according to claim 1, characterized in that The establishing a second optimization configuration model for installing reactive power compensation devices and energy storage devices on the power line includes: By establishing a second objective function; By establishing a fourth constraint condition; By establishing a fifth constraint condition; Establishing a second optimization configuration model according to the second objective function, the fourth constraint condition and the fifth constraint condition; Among them, is the capacitance of the reactive power compensation device, is the rated power of the energy storage device; 、 are the configuration costs of the reactive power compensation device and the energy storage device respectively; is the angular frequency; is the maximum fluctuation of the active power; is the maximum fluctuation of the reactive power; is the reactance of the power line; and are the voltage amplitudes of the nodes at both ends of the power line respectively.

8. A method for compensating grid voltage considering new energy fluctuations as described in claim 1, characterized in that, The solving the first optimization configuration model and the second optimization configuration model according to the reactive power compensation amount to generate a compensation configuration scheme for the grid voltage includes: Inputting the reactive power compensation amount into the first optimization configuration model and the second optimization configuration model; Using a nonlinear programming algorithm to solve the first optimization configuration model and the second optimization configuration model respectively to obtain a first objective value and a second objective value; Generating a compensation configuration scheme for the grid voltage according to the optimization configuration model corresponding to the smaller value among the first objective value and the second objective value.

9. A method for compensating grid voltage considering new energy fluctuations according to claim 8, characterized in that, The using a nonlinear programming algorithm to solve the first optimization configuration model and the second optimization configuration model respectively to obtain a first objective value and a second objective value includes: Selecting the initial parameter values of the first optimization configuration model and the second optimization configuration model; the initial parameter values include the initial capacitance value of the reactive power compensation device, the initial capacitance value of the series capacitor, the initial power value of the energy storage device, and the voltage amplitudes at both ends of the power line. Using a non - linear programming algorithm, solve the first optimization configuration model and the second optimization configuration model according to the initial parameter values to obtain a first objective value and a second objective value respectively.

10. A power grid voltage compensation system considering new energy fluctuations, characterized in that, It includes: A voltage drop value calculation module for calculating the voltage drop value of the nodes accessing new energy in the power line; A reactive power compensation amount calculation module for calculating the reactive power compensation amount with the lowest total voltage amplitude loss of the power line as the goal according to the voltage drop value; A first model establishment module for establishing a first optimization configuration model of installing a reactive power compensation device, a series capacitor and an energy storage device on the power line; A second model establishment module for establishing a second optimization configuration model of installing a reactive power compensation device and an energy storage device on the power line; A compensation scheme generation module for solving the first optimization configuration model and the second optimization configuration model according to the reactive power compensation amount and generating a compensation configuration scheme for the grid voltage.

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