A grid voltage compensation method and system considering renewable energy fluctuations

Abstract

The present invention discloses a grid voltage compensation method and system that takes into account fluctuations in renewable energy sources. This method relates to the field of power line optimization technology. The method calculates the voltage drop at nodes connected to renewable energy sources in a power line. Based on the voltage drop, the reactive compensation amount is calculated with the goal of minimizing the total voltage amplitude loss of the power line. A first optimization configuration model is established for installing a reactive compensation device, a series capacitor, and an energy storage device on the power line. A second optimization configuration model is established for installing a reactive compensation device and an energy storage device on the power line. Based on the reactive compensation amount, the first and second optimization configuration models are solved to generate a grid voltage compensation configuration scheme. By using embodiments of the present invention, the reactive compensation device, series capacitor, and energy storage device can be combined to improve the voltage quality of the regional power grid while timely regulating the voltage drop of the power line.

Description

Technical Field

[0001] The present invention relates to the technical field of power line optimization, and in particular to a grid voltage compensation method and system taking into account renewable energy fluctuations. Background Art

[0002] The integration of distributed renewable energy into the power system introduces greater volatility on the load side. At the same time, there is a risk of low-voltage or high-voltage grid disconnection due to renewable energy. Voltage fluctuations caused by load fluctuations or failures of some renewable energy sources will affect the system voltage quality and may even cause nearby renewable energy units to disconnect from the grid, leading to concentrated grid disconnection accidents.

[0003] Voltage compensation is a crucial measure for improving system voltage distribution and power quality. Existing research on voltage compensation has mostly considered the use of reactive power compensation devices, such as capacitors. However, when renewable energy fluctuates significantly, the required reactive power compensation device capacity increases rapidly, placing high demands on the equipment's performance. Summary of the Invention

[0004] The embodiments of the present invention provide a grid voltage compensation method and system that takes into account fluctuations in renewable energy sources. The method and system can combine reactive power compensation devices, series capacitors, and energy storage devices to improve the voltage quality of the regional grid while timely regulating the voltage drop of the power lines.

[0005] An embodiment of the present invention provides a grid voltage compensation method that takes into account renewable energy fluctuations, including:

[0006] Calculate the voltage drop value at the node where the new energy is connected in the power line;

[0007] According to the voltage drop value, with the goal of minimizing the total voltage amplitude loss of the power line, calculating the reactive compensation amount;

[0008] Establishing a first optimal configuration model for installing reactive power compensation devices, series capacitors, and energy storage devices on power lines;

[0009] Establishing a second optimal configuration model for adding reactive power compensation devices and energy storage devices to power lines;

[0010] The first optimization configuration model and the second optimization configuration model are solved according to the reactive compensation amount to generate a compensation configuration scheme for the grid voltage.

[0011] As an improvement to the above solution, the step of calculating the voltage drop value at a node connected to a new energy source in a power line includes:

[0012] Dividing a voltage drop vector at both ends of a power line into a longitudinal component and a transverse component; one end of the power line is a first node connected to a new energy source, and the other end is a second node connected to the first node;

[0013] The voltage drop value caused by the active power fluctuation of the new energy is calculated based on the transverse component and the voltage phase angle difference at both ends of the power line.

[0014] As an improvement to the above solution, the voltage drop vector at both ends of the power line is divided into a longitudinal component and a transverse component, including:

[0015] Get 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;

[0016] in, 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.

[0017] As an improvement to the above solution, the voltage drop value caused by the fluctuation of the active power of the renewable energy is calculated based on the transverse component and the voltage phase angle difference at both ends of the power line, including:

[0018] Get the voltage phase angle difference between the first node i and the second node j of the power line ;

[0019] pass Calculate the voltage drop value caused by the active power fluctuation of new energy; where, is the voltage amplitude of the first node i.

[0020] As an improvement to the above solution, the reactive compensation amount is calculated based on the voltage drop value with the goal of minimizing the total voltage amplitude loss, including:

[0021] Constructing a scenario in which reactive power compensation completely offsets the voltage drop value, and obtaining a minimum total voltage amplitude loss expression based on the scenario;

[0022] Solve the minimum total voltage amplitude loss expression to obtain the required reactive power compensation amount.

[0023] As an improvement to the above solution, the first optimization configuration model for installing a reactive compensation device, a series capacitor, and an energy storage device on the power line includes:

[0024] pass Establish the first objective function;

[0025] pass Establish the first constraint;

[0026] pass Establish the second constraint;

[0027] pass Establish the third constraint;

[0028] 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;

[0029] in, is the capacitance of the series capacitor, is the capacitance of the reactive compensation device, is the rated power of the energy storage device; 、 、 are the configuration costs of series capacitors, reactive compensation devices, and energy storage devices, 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 the nodes at both ends of the power line.

[0030] As an improvement to the above solution, the second optimization configuration model for installing reactive power compensation devices and energy storage devices on the power lines includes:

[0031] pass Establish the second objective function;

[0032] pass Establish the fourth constraint;

[0033] pass Establish the fifth constraint;

[0034] Establishing a second optimization configuration model according to the second objective function, the fourth constraint condition, and the fifth constraint condition;

[0035] in, is the capacitance of the reactive compensation device, is the rated power of the energy storage device; 、 are the configuration costs of reactive 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 the nodes at both ends of the power line.

[0036] As an improvement to the above solution, solving the first optimization configuration model and the second optimization configuration model according to the reactive compensation amount to generate a compensation configuration solution for the grid voltage includes:

[0037] Inputting the reactive compensation amount into the first optimization configuration model and the second optimization configuration model;

[0038] Solving the first optimization configuration model and the second optimization configuration model respectively using a nonlinear programming algorithm to obtain a first target value and a second target value;

[0039] A compensation configuration scheme for the grid voltage is generated according to the optimization configuration model corresponding to the smaller value between the first target value and the second target value.

[0040] As an improvement to the above solution, the method of using a 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:

[0041] Selecting initial values ​​of parameters of the first optimization configuration model and the second optimization configuration model; the initial values ​​of the parameters include an initial value of capacitance of the reactive compensation device, an initial value of capacitance of the series capacitor, an initial value of power of the energy storage device, and a voltage amplitude at both ends of the power line;

[0042] A nonlinear programming algorithm is used to solve the first optimization configuration model and the second optimization configuration model according to the initial parameter values ​​to obtain a first target value and a second target value respectively.

[0043] An embodiment of the present invention further provides a grid voltage compensation system that takes into account fluctuations in renewable energy, including:

[0044] A voltage drop value calculation module is used to calculate the voltage drop value of the node connected to the new energy in the power line;

[0045] a reactive compensation amount calculation module, configured to calculate the reactive compensation amount based on the voltage drop value and with the goal of minimizing the total voltage amplitude loss of the power line;

[0046] A first model building module is used to build a first optimization configuration model for adding a reactive compensation device, a series capacitor, and an energy storage device to the power line;

[0047] A second model building module is used to build a second optimization configuration model for adding reactive power compensation devices and energy storage devices to the power lines;

[0048] A compensation scheme generating module is used to solve the first optimization configuration model and the second optimization configuration model according to the reactive compensation amount, and generate a compensation configuration scheme for the grid voltage.

[0049] Compared with the prior art, the present invention discloses a grid voltage compensation method and system that takes into account fluctuations in renewable energy sources. The method calculates the voltage drop value of nodes connected to renewable energy sources in a power line; based on the voltage drop value, the reactive compensation amount is calculated with the goal of minimizing the total voltage amplitude loss of the power line; a first optimization configuration model is established for installing a reactive compensation device, a series capacitor, and an energy storage device on the power line; a second optimization configuration model is established for installing a reactive compensation device and an energy storage device on the power line; and based on the reactive compensation amount, the first optimization configuration model and the second optimization configuration model are solved to generate a compensation configuration scheme for the grid voltage. By using the embodiments of the present invention, the optimal configuration scheme can be selected from the combination of reactive compensation devices, series capacitors, and energy storage devices to adjust the system voltage, fully considering the principles of layered and partitioned reactive compensation and local balancing, and is suitable for large-scale access to distributed renewable energy sources, achieving both economical and practical benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 This is a schematic flow chart of the steps of a grid voltage compensation method considering renewable energy fluctuations provided by an embodiment of the present invention;

[0051] Figure 2 This is a schematic diagram of the structure of an IEEE nine-node power system provided by an embodiment of the present invention;

[0052] Figure 3 is a reactive compensation amount curve diagram provided by an embodiment of the present invention;

[0053] Figure 4 This is a structural diagram of a grid voltage compensation system that takes into account fluctuations in renewable energy, provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0054] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0055] In the description of the specification and claims, it should be understood that the terms "first," "second," etc., are used solely for descriptive purposes to distinguish between identical technical features and are not to be construed as indicating or implying relative importance or implicitly specifying the number of technical features being referred to, nor do they necessarily describe a sequential or chronological order. The terms are interchangeable where appropriate. Thus, a feature specified as "first" or "second" may explicitly or implicitly include at least one of those features.

[0056] Renewable energy power stations, such as photovoltaic and wind power, adjust their output through grid-connected inverters, typically achieving a power factor exceeding 0.98. Therefore, the impact of fluctuations in renewable energy sources is primarily reflected in active power. In addition to affecting system frequency, fluctuations in active power in the power system can also cause system voltage anomalies or even collapse.

[0057] The voltage compensation method based on the existing technology that only configures reactive power compensation devices cannot adapt well to the fluctuation of renewable energy. Figure 1 , an embodiment of the present invention provides a grid voltage compensation method considering renewable energy fluctuations, which is specifically performed through steps S1 to S5:

[0058] S1. Calculate the voltage drop value at the node where the new energy source is connected in the power line.

[0059] S2. Calculate the reactive compensation amount based on the voltage drop value and with the goal of minimizing the total voltage amplitude loss of the power line.

[0060] S3. Establish a first optimal configuration model for installing reactive power compensation devices, series capacitors, and energy storage devices on the power lines.

[0061] S4. Establish a second optimal configuration model by adding reactive power compensation devices and energy storage devices to the power lines.

[0062] S5. Solve the first optimization configuration model and the second optimization configuration model according to the reactive compensation amount to generate a compensation configuration scheme for the grid voltage.

[0063] The embodiments of the present invention establish two optimization configuration models that can flexibly select the optimal compensation configuration scheme based on the actual conditions of the power line to meet the voltage compensation requirements in different power grid scenarios. By adding a reactive power compensation device to the power line, reactive power can be quickly adjusted; adding an energy storage device can effectively smooth out some active power fluctuations; and adding a series capacitor can also reduce line reactance. The implementation of the embodiments of the present invention not only reduces the impact of renewable energy fluctuations on the power line, but also the energy storage device and series capacitor can effectively reduce the required reactive power compensation device configuration capacity, thereby improving the economic efficiency of the line.

[0064] In the above scheme, the optimal configuration scheme can be selected from the combination of reactive compensation devices, series capacitors and energy storage devices to adjust the system voltage, fully considering the principles of layered and zoned reactive compensation and local balancing, and is suitable for large-scale access of distributed new energy, and is both economical and practical.

[0065] As a preferred embodiment, step S1, calculating the voltage drop value of the node connected to the new energy in the power line, is performed through steps S11-S12:

[0066] S11. Dividing a voltage drop vector at both ends of a power line into a longitudinal component and a transverse component; one end of the power line is a first node connected to a new energy source, and the other end is a second node connected to the first node;

[0067] S12. Calculate the voltage drop value caused by the active power fluctuation of the new energy according to the transverse component and the voltage phase angle difference at both ends of the power line.

[0068] It should be noted that the voltage drop vector is typically a complex number. Decomposing it into its longitudinal and transverse components converts complex vector operations into relatively simple real number operations, facilitating subsequent calculations and analysis. In power systems, the longitudinal component primarily relates to active and reactive power, while the transverse component relates to the voltage phase angle. This decomposition clearly demonstrates the relationship between these physical quantities.

[0069] It should also be noted that in regional regulatory power grids, the line reactance is usually much greater than the line resistance, so the active power fluctuations of renewable energy mainly affect the transverse component of the line voltage drop.

[0070] Furthermore, preferably, step S11, dividing the voltage drop vector at both ends of the power line into a longitudinal component and a transverse component, includes:

[0071] Get 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;

[0072] in, 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.

[0073] It should be noted that, in the embodiment of the present invention, the two ends of the power line are the first node and the second node respectively, the new energy unit is introduced at the first node, and the direction of power flow is from the first node to the second node. It can also be expressed as , the voltage drop vector is is the reference vector.

[0074] Furthermore, preferably, step S12, calculating the voltage drop value caused by the active power fluctuation of the renewable energy source based on the transverse component and the voltage phase angle difference at both ends of the power line, includes:

[0075] Get the voltage phase angle difference between the first node i and the second node j of the power line ;

[0076] pass Calculate the voltage drop value caused by the active power fluctuation of new energy; where, is the voltage amplitude of the first node i.

[0077] according to It can be seen that when the line reactance X is much larger than the line resistance R, the fluctuation of the active power of renewable energy will mainly affect the transverse component of the line voltage drop.

[0078] In the embodiment 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, the voltage phase angle difference between the two ends of the regional power grid line is usually small. Approximately calculate the voltage phase angle difference The cosine value of , when calculating the cosine function, retaining the quadratic term of the Maclaurin formula, we get . Then Substituting this into the equation, we can get the voltage drop value caused by the active power fluctuation of renewable energy. .

[0079] As a preferred embodiment, step S2, calculating the reactive compensation amount based on the voltage drop value with the goal of minimizing the total voltage amplitude loss, includes:

[0080] Constructing a scenario in which reactive power compensation completely offsets the voltage drop value, and obtaining a minimum total voltage amplitude loss expression based on the scenario;

[0081] Solve the minimum total voltage amplitude loss expression to obtain the required reactive power compensation amount.

[0082] For example, the minimum total voltage amplitude loss is expressed as ; By solving the above formula, the required reactive compensation amount is .

[0083] Calculations of reactive power compensation show that for voltage fluctuations caused by renewable energy fluctuations, if reactive power compensation is used to suppress voltage drops, the required reactive power compensation is proportional to the square of the active power fluctuation and the magnitude of the line reactance, and inversely proportional to the voltage amplitude at the nodes at both ends of the line. Therefore, when the absolute value of renewable energy fluctuations is small, it is more economical to regulate voltage using reactive power compensation devices. However, when renewable energy fluctuations are large, the required reactive power compensation device capacity will increase rapidly due to the relationship between reactive power compensation and the square of the active power fluctuation. Directly using high-capacity reactive power compensation devices may result in redundant configurations and be uneconomical.

[0084] As a preferred embodiment, step S3, establishing a first optimization configuration model for installing a reactive power compensation device, a series capacitor, and an energy storage device on the power line, includes:

[0085] pass Establish the first objective function;

[0086] pass Establish the first constraint;

[0087] pass Establish the second constraint;

[0088] pass Establish the third constraint;

[0089] 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;

[0090] in, is the capacitance of the series capacitor, is the capacitance of the reactive compensation device, is the rated power of the energy storage device; 、 、 are the configuration costs of series capacitors, reactive compensation devices, and energy storage devices, 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 the nodes at both ends of the power line.

[0091] In the first optimization configuration model, in addition to the existing technology of adding reactive power compensation devices, a solution is also proposed to add series capacitors and energy storage devices. The energy storage device can smooth some active power fluctuations, effectively reducing the required reactive power compensation device configuration capacity and achieving more economical system voltage regulation. The addition of series capacitors to the line can reduce line impedance, thereby reducing the configuration capacity of the reactive power compensation device from another perspective.

[0092] It should be noted that, in the embodiment of the present invention, 、 and Both can be 0, indicating that the corresponding device is not configured.

[0093] As a preferred embodiment, step S4, establishing a second optimal configuration model for installing a reactive power compensation device and an energy storage device on the power line, includes:

[0094] pass Establish the second objective function;

[0095] pass Establish the fourth constraint;

[0096] pass Establish the fifth constraint;

[0097] Establishing a second optimization configuration model according to the second objective function, the fourth constraint condition, and the fifth constraint condition;

[0098] in, is the capacitance of the reactive compensation device, is the rated power of the energy storage device; 、 are the configuration costs of reactive 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 the nodes at both ends of the power line.

[0099] Considering that the demand for reactive power compensation is small in some power grid scenarios, the first optimization configuration model cannot express the value of the current distribution model without configuring series capacitors. In the extreme case, the embodiment of the present invention further provides a second optimization configuration model. The first optimization configuration model and the second optimization configuration model can effectively give full play to the advantages of each device and achieve the best voltage compensation effect.

[0100] As a preferred embodiment, step S5, solving the first optimization configuration model and the second optimization configuration model according to the reactive compensation amount to generate a compensation configuration scheme for the grid voltage, includes:

[0101] Inputting the reactive compensation amount into the first optimization configuration model and the second optimization configuration model;

[0102] Solving the first optimization configuration model and the second optimization configuration model respectively using a nonlinear programming algorithm to obtain a first target value and a second target value;

[0103] A compensation configuration scheme for the grid voltage is generated according to the optimization configuration model corresponding to the smaller value between the first target value and the second target value.

[0104] It's important to note that nonlinear programming algorithms are suitable for solving optimization problems involving nonlinear objective functions and constraints. This algorithm can find the optimal solution to the objective function while satisfying various constraints. This means obtaining the first objective value for the first optimization configuration model and the second objective value for the second optimization configuration model.

[0105] Furthermore, preferably, the using of a nonlinear programming algorithm to solve the first optimization configuration model and the second optimization configuration model respectively to obtain a first target value and a second target value includes:

[0106] Selecting initial values ​​of parameters of the first optimization configuration model and the second optimization configuration model; the initial values ​​of the parameters include an initial value of capacitance of the reactive compensation device, an initial value of capacitance of the series capacitor, an initial value of power of the energy storage device, and a voltage amplitude at both ends of the power line;

[0107] A nonlinear programming algorithm is used to solve the first optimization configuration model and the second optimization configuration model according to the initial parameter values ​​to obtain a first target value and a second target value respectively.

[0108] In nonlinear programming algorithms, the values ​​of variables are continuously updated through iterative calculations so that the objective function gradually converges. Therefore, it is necessary to select initial values ​​for each variable.

[0109] For example, each physical quantity adopts per unit value, and the initial value of the capacitance of the reactive compensation device is The initial value of the power of the energy storage device is 0, and the initial value of the capacitance of the series capacitor is , the voltage amplitude at both ends of the power line is a constant 1.

[0110] In a preferred embodiment, the present invention is applied to Figure 2 The grid voltage compensation process of the IEEE 9-bus power system is shown in Figure 1. Figure 2In the figure, numbers represent node numbers, and G represents the power node. A renewable energy generator is connected to node 9. The maximum fluctuations in active power and reactive power at this node, caused by both renewable energy and load, are 142 MW and 25 Mvar, respectively.

[0111] Considering the voltage stability under the N-1 fault condition, static safety analysis shows that when branch 4-9 is disconnected, the voltage drop at node 9 is the largest. In this scenario, after further considering the voltage drop caused by the power fluctuation at node 9, voltage compensation is used to restore the voltage at node 9 to its initial level.

[0112] If only a reactive power compensation device is installed at node 9 to adjust the voltage in the prior art, the following result will be obtained: Figure 3 The solid line shows the reactive compensation amount, which can restore the voltage of the node 9 to the initial level.

[0113] It can be seen that reactive power compensation can compensate for the system voltage changes caused by renewable energy fluctuations, and the least squares curve fitting analysis shows that there is an approximate quadratic function relationship between the required reactive power compensation amount and the active power fluctuation amount.

[0114] Furthermore, the error of curve fitting is measured by the root mean square error indicator. The root mean square error is calculated to be 1.0547, where s is the sample point number, u(s) is the function to be fitted, y(s) is the fitting function, and Ns is the number of sample points. The dimension of the root mean square error is the same as that of the original function. Figure 2 Compared with the mean value of reactive compensation shown by the solid line, the relative error is 1.32%, which is a very small fitting error.

[0115] In the first optimal configuration model established by the method according to the embodiment of the present invention, the series capacitors are installed at branches 4-9 and 8-9. s =c p =1.05×10 5 Yuan / μF, c b =1.93×10 6 The first objective function is established using a power factor of RMB / MVA and ω = 314.16 rad / s. Solving the first optimization configuration model yields a reactive compensation device with a capacity of 3.0 × 10⁻³ F, a series capacitor with a capacity of 7.74 × 10⁻⁦ F, and an energy storage device with a capacity of 0, resulting in a total cost of RMB 3.301 × 10⁻⁸.

[0116] In addition, a second optimization configuration model was established and solved, and the configuration capacity of the reactive compensation device was obtained to be 3.6×10-3F, the configuration capacity of the energy storage device to be 11.5MW, and the total cost to be 3.988×108 yuan.

[0117] 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, a series capacitor with a configuration capacity of 7.74×10-5F is installed on branches 4-9 and branches 8-9, and a reactive compensation device with a configuration capacity of 3.0×10-3F is installed at node 9.

[0118] Figure 3 The wide dashed line shows the reactive compensation amount required to cope with voltage drop under the compensation configuration scheme provided in the embodiment of the present invention. It can be seen that by adopting the embodiment of the present invention, the configuration capacity of the reactive compensation device can be effectively reduced at a lower cost.

[0119] The grid voltage compensation method that takes into account renewable energy fluctuations, provided by an embodiment of the present invention, can select the optimal configuration scheme from the combination of reactive power compensation devices, series capacitors, and energy storage devices to adjust the system voltage. This fully considers the principles of layered and zoned reactive power compensation and local balancing, and is suitable for large-scale access to distributed renewable energy, achieving both economical and practical benefits.

[0120] The embodiment of the present invention provides a grid voltage compensation system that takes into account the fluctuation of renewable energy. Figure 4 The grid voltage compensation system considering the fluctuation of renewable energy sources includes a voltage drop value calculation module 11, a reactive compensation amount calculation module 12, a first model establishment module 13, a second model establishment module 14 and a compensation scheme generation module 15, wherein:

[0121] The voltage drop value calculation module 11 is used to calculate the voltage drop value of the node connected to the new energy in the power line;

[0122] The reactive compensation amount calculation module 12 is used to calculate the reactive compensation amount according to the voltage drop value with the goal of minimizing the total voltage amplitude loss of the power line;

[0123] A first model building module 13 is used to build a first optimization configuration model for adding a reactive compensation device, a series capacitor, and an energy storage device to the power line;

[0124] A second model building module 14 is used to build a second optimal configuration model for adding a reactive compensation device and an energy storage device to the power line;

[0125] The compensation scheme generating module 15 is configured to solve the first optimization configuration model and the second optimization configuration model according to the reactive compensation amount, and generate a compensation configuration scheme for the grid voltage.

[0126] As a preferred embodiment, the voltage drop value calculation module 11 includes:

[0127] a vector division unit, configured to divide a voltage drop vector at both ends of a power line into a longitudinal component and a transverse component; one end of the power line being a first node connected to a new energy source, and the other end being a second node connected to the first node;

[0128] The voltage drop value calculation unit is used to calculate the voltage drop value caused by the active power fluctuation of the new energy according to the transverse component and the voltage phase angle difference at both ends of the power line.

[0129] Furthermore, preferably, the vector division unit is specifically used to:

[0130] Get 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;

[0131] in, 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.

[0132] Furthermore, preferably, the falling value calculation unit is used to:

[0133] Get the voltage phase angle difference between the first node i and the second node j of the power line ;

[0134] pass Calculate the voltage drop value caused by the active power fluctuation of new energy; where, is the voltage amplitude of the first node i.

[0135] As a preferred implementation, the reactive compensation amount calculation module 12 is specifically configured to:

[0136] Constructing a scenario in which reactive power compensation completely offsets the voltage drop value, and obtaining a minimum total voltage amplitude loss expression based on the scenario;

[0137] Solve the minimum total voltage amplitude loss expression to obtain the required reactive power compensation amount.

[0138] As a preferred embodiment, the first model building module 13 is specifically configured to:

[0139] pass Establish the first objective function;

[0140] pass Establish the first constraint;

[0141] pass Establish the second constraint;

[0142] pass Establish the third constraint;

[0143] 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;

[0144] in, is the capacitance of the series capacitor, is the capacitance of the reactive compensation device, is the rated power of the energy storage device; 、 、 are the configuration costs of series capacitors, reactive compensation devices, and energy storage devices, 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 the nodes at both ends of the power line.

[0145] As a preferred embodiment, the second model building module 14 is specifically configured to:

[0146] pass Establish the second objective function;

[0147] pass Establish the fourth constraint;

[0148] pass Establish the fifth constraint;

[0149] Establishing a second optimization configuration model according to the second objective function, the fourth constraint condition, and the fifth constraint condition;

[0150] in, is the capacitance of the reactive compensation device, is the rated power of the energy storage device; 、 are the configuration costs of reactive 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 the nodes at both ends of the power line.

[0151] As a preferred implementation, the compensation scheme generating module 15 includes:

[0152] a parameter substitution unit, configured to input the reactive compensation amount into the first optimization configuration model and the second optimization configuration model;

[0153] a model solving unit, configured to solve the first optimization configuration model and the second optimization configuration model respectively by using a nonlinear programming algorithm to obtain a first target value and a second target value;

[0154] A scheme generating unit is used to generate a compensation configuration scheme for the grid voltage according to the optimization configuration model corresponding to the smaller value of the first target value and the second target value.

[0155] Furthermore, preferably, the model solving unit is specifically used to:

[0156] Selecting initial values ​​of parameters of the first optimization configuration model and the second optimization configuration model; the initial values ​​of the parameters include an initial value of capacitance of the reactive compensation device, an initial value of capacitance of the series capacitor, an initial value of power of the energy storage device, and a voltage amplitude at both ends of the power line;

[0157] A nonlinear programming algorithm is used to solve the first optimization configuration model and the second optimization configuration model according to the initial parameter values ​​to obtain a first target value and a second target value respectively.

[0158] The grid voltage compensation system that takes into account renewable energy fluctuations, provided by an embodiment of the present invention, can select the optimal configuration scheme from the combination of reactive power compensation devices, series capacitors, and energy storage devices to adjust the system voltage, fully considering the principles of layered and zoned reactive power compensation and local balancing, and is suitable for large-scale access to distributed renewable energy, combining economy and practicality.

[0159] Those skilled in the art will appreciate that all or part of the processes in the above-described method embodiments can be implemented by instructing the relevant hardware through a computer program. The program can be stored in a computer-readable storage medium, and when executed, the program can include the processes in the above-described method embodiments. The storage medium can be a magnetic disk, an optical disk, a read-only memory (ROM), or a random access memory (RAM).

[0160] The above is a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A grid voltage compensation method considering renewable energy fluctuations, characterized in that: include: Calculate the voltage drop value at the node where the new energy is connected in the power line; According to the voltage drop value, with the goal of minimizing the total voltage amplitude loss of the power line, calculating the reactive compensation amount; Establishing a first optimal configuration model for installing reactive power compensation devices, series capacitors, and energy storage devices on power lines; Establishing a second optimal configuration model for adding reactive power compensation devices and energy storage devices to power lines; Solving the first optimization configuration model and the second optimization configuration model according to the reactive compensation amount to generate a compensation configuration scheme for the grid voltage; The first optimization configuration model for installing a reactive compensation device, a series capacitor, and an energy storage device on the power line includes: pass Establish the first objective function; pass Establish the first constraint; pass Establish the second constraint; pass Establish the third constraint; 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; in, is the capacitance of the series capacitor, is the capacitance of the reactive compensation device, is the rated power of the energy storage device; 、 、 are the configuration costs of series capacitors, reactive compensation devices, and energy storage devices, 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 the nodes at both ends of the power line respectively; The second optimization configuration model for installing a reactive power compensation device and an energy storage device on the power line includes: pass Establish the second objective function; pass Establish the fourth constraint; pass Establish the fifth constraint; Establishing a second optimization configuration model according to the second objective function, the fourth constraint condition, and the fifth constraint condition; in, is the capacitance of the reactive compensation device, is the rated power of the energy storage device; 、 are the configuration costs of reactive 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 the nodes at both ends of the power line.

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

3. A grid voltage compensation method considering new energy fluctuations according to claim 2, characterized in that: The step of dividing the voltage drop vector at both ends of the power line into a longitudinal component and a transverse component includes: Get 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; in, 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 grid voltage compensation method considering renewable energy fluctuations according to claim 3, characterized in that: The calculating of the voltage drop value caused by the fluctuation of the active power of the renewable energy source according to the transverse component and the voltage phase angle difference at both ends of the power line includes: Get the voltage phase angle difference between the first node i and the second node j of the power line ; pass Calculate the voltage drop value caused by the active power fluctuation of new energy; where, is the voltage amplitude of the first node i.

5. The grid voltage compensation method considering the fluctuation of new energy sources according to claim 1, characterized in that: The reactive compensation amount is calculated based on the voltage drop value with the goal of minimizing the total voltage amplitude loss, including: Constructing a scenario in which reactive power compensation completely offsets the voltage drop value, and obtaining a minimum total voltage amplitude loss expression based on the scenario; Solve the minimum total voltage amplitude loss expression to obtain the required reactive power compensation amount.

6. A grid voltage compensation method considering renewable energy fluctuations according to claim 1, characterized in that: The step of solving the first optimization configuration model and the second optimization configuration model according to the reactive compensation amount to generate a compensation configuration scheme for the grid voltage includes: Inputting the reactive compensation amount into the first optimization configuration model and the second optimization configuration model; Solving the first optimization configuration model and the second optimization configuration model respectively using a nonlinear programming algorithm to obtain a first target value and a second target value; A compensation configuration scheme for the grid voltage is generated according to the optimization configuration model corresponding to the smaller value between the first target value and the second target value.

7. A grid voltage compensation method considering renewable energy fluctuations according to claim 6, characterized in that: The method of using a nonlinear programming algorithm to solve the first optimization configuration model and the second optimization configuration model respectively to obtain a first target value and a second target value includes: Selecting initial values ​​of parameters of the first optimization configuration model and the second optimization configuration model; the initial values ​​of the parameters include an initial value of capacitance of the reactive compensation device, an initial value of capacitance of the series capacitor, an initial value of power of the energy storage device, and a voltage amplitude at both ends of the power line; A nonlinear programming algorithm is used to solve the first optimization configuration model and the second optimization configuration model according to the initial parameter values ​​to obtain a first target value and a second target value respectively.

8. A grid voltage compensation system considering new energy fluctuations, characterized in that: include: A voltage drop value calculation module is used to calculate the voltage drop value of the node connected to the new energy in the power line; a reactive compensation amount calculation module, configured to calculate the reactive compensation amount based on the voltage drop value and with the goal of minimizing the total voltage amplitude loss of the power line; A first model building module is used to build a first optimization configuration model for adding a reactive compensation device, a series capacitor, and an energy storage device to the power line; A second model building module is used to build a second optimization configuration model for adding reactive power compensation devices and energy storage devices to the power lines; a compensation scheme generating module, configured to solve the first optimization configuration model and the second optimization configuration model according to the reactive compensation amount, and generate a compensation configuration scheme for the grid voltage; The first model building module is specifically used to: pass Establish the first objective function; pass Establish the first constraint; pass Establish the second constraint; pass Establish the third constraint; 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; in, is the capacitance of the series capacitor, is the capacitance of the reactive compensation device, is the rated power of the energy storage device; 、 、 are the configuration costs of series capacitors, reactive compensation devices, and energy storage devices, 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 the nodes at both ends of the power line respectively; The second model building module is specifically used to: pass Establish the second objective function; pass Establish the fourth constraint; pass Establish the fifth constraint; Establishing a second optimization configuration model according to the second objective function, the fourth constraint condition, and the fifth constraint condition; in, is the capacitance of the reactive compensation device, is the rated power of the energy storage device; 、 are the configuration costs of reactive 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 the nodes at both ends of the power line.

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