New energy model test method and system based on network side power supply optimization

Abstract

The invention discloses a new energy model test method and system based on grid-side power supply optimization, and the method comprises the steps: calculating the unit voltage of a new energy grid-connected system after the equivalence of a power grid, and the active power and reactive power emitted by a new energy unit; analyzing the relationship between the terminal voltage of the new energy unit and the active power and reactive power; calculating an infinite power supply voltage amplitude based on the relationship between the terminal voltage of the new energy unit and the active power and the reactive power; and based on the infinite power supply voltage amplitude, obtaining the machine end short-circuit ratio of the new energy unit i, and calculating the system impedance and the infinite system voltage under full power.

Description

Technical Field

[0001] This invention relates to the field of power system safety and stability control technology, and more specifically, to a new energy model testing method and system based on grid-side power source optimization. Background Technology

[0002] As the proportion of new energy sources such as wind power and photovoltaics in the power system gradually increases, a high proportion of new energy is becoming an important trend and key characteristic of power system development. The large number of new energy grid-connected devices using power electronic devices as interfaces significantly alters the characteristics of AC grids dominated by synchronous machines. Power electronic devices lack the mechanical inertia of synchronous machines and have poor disturbance rejection performance, resulting in a weakening of the electrical strength of AC grids connected to new energy sources. Especially when large-scale new energy power plants are connected to the AC grid, complex coupling relationships arise between new energy units and the AC grid, as well as among the new energy units themselves, leading to a series of stability issues.

[0003] The short-circuit ratio is commonly used to measure the strength of an AC power grid. Studies have found that the integration of new energy sources lowers the short-circuit ratio of grids previously dominated by thermal power. This decrease in the grid's short-circuit ratio leads to a reduction in system stability margin and the capacity of new energy sources to support power generation. These issues constrain the reactive power balance construction of new energy units at full power and limit testing methods for new energy sources under low short-circuit ratios. Therefore, researching reactive power balance construction schemes for new energy models in grids with low short-circuit ratios can effectively contribute to the development of new energy sources. Summary of the Invention

[0004] According to the present invention, a new energy model testing method and system based on grid-side power supply optimization is provided to solve the technical problem of constructing reactive power balance of grid-connected transmission power of new energy power plants under low short-circuit ratio.

[0005] According to a first aspect of the present invention, a method for testing new energy models based on grid-side power optimization is provided, comprising:

[0006] Calculate the voltage of the new energy grid-connected system units, and the active and reactive power generated by the new energy units after being equivalent to the power grid.

[0007] Analyze the relationship between the terminal voltage of new energy generating units and active and reactive power;

[0008] Based on the relationship between the terminal voltage of the new energy generator unit and the active and reactive power, the amplitude of the infinite power supply voltage is calculated.

[0009] Based on the infinite power supply voltage amplitude, the short-circuit ratio of the i-terminal of the new energy unit is obtained, and the system impedance and infinite system voltage under full power are calculated.

[0010] Optionally, the calculation includes the voltage of the renewable energy grid-connected system units, and the active and reactive power generated by the renewable energy units after being equivalent to the grid, including:

[0011] Calculate the terminal voltage of the new energy unit based on the infinite power supply voltage, line impedance, and line current:

[0012]

[0013] in, For the terminal voltage of new energy generating units, The voltage of the infinite power supply is... R is the line current. S X is the line resistance. S For line inductance;

[0014] Calculate the active and reactive power generated by the new energy generating units:

[0015] Assumption The apparent power delivered by the new energy unit to the infinite power source is calculated as follows:

[0016]

[0017] By separating the real part of apparent power (active power) and the imaginary part (reactive power), we obtain the expressions for active power and reactive power:

[0018]

[0019] Optionally, the relationship between the terminal voltage of the new energy generating unit and its active and reactive power is analyzed, including:

[0020] The expressions for active power and reactive power u 2 Moving the term to the left side of the equation yields:

[0021]

[0022] Z 2 =R 2 +X 2 Substituting into the above equation and summing the squares of the active and reactive terms, we obtain the fourth-order equation for the terminal voltage:

[0023] u 4 -(2PR+2QX+E 2 )u 2 +Z 2 (P 2 +Q 2 )=0 (1)

[0024] Solving the equation yields the expression for the square of the terminal voltage:

[0025]

[0026] Taking the square root yields the voltage expression.

[0027]

[0028] Since the line resistance in a single-machine infinite bus system is often small and negligible, ignoring R, we can obtain:

[0029]

[0030] The voltage expression is derived as follows:

[0031]

[0032] Optionally, based on the relationship between the terminal voltage of the new energy unit and the active and reactive power, the amplitude of the infinite power supply voltage is calculated, including:

[0033] Moving the infinite power supply voltage term to the left side of the equation yields the relationship between the infinite power supply voltage and the transmission power.

[0034]

[0035] The method for calculating the voltage amplitude of an infinite power source is as follows:

[0036]

[0037] Optionally, based on the infinite power supply voltage amplitude, the short-circuit ratio at the i-terminal of the new energy unit is obtained, and the system impedance and infinite system voltage at full power are calculated, including:

[0038] Based on the short-circuit ratio index SCR-S of capacity, the short-circuit ratio of the i-terminal of the new energy unit is determined as follows:

[0039]

[0040] Where i and j represent new energy unit i and new energy unit j respectively, P REi and P REj U represents the active power injected by new energy unit i and new energy unit j, respectively. i and U j Z represents the terminal voltage of new energy unit i and new energy unit j. eq This is the equivalent impedance matrix of the AC power grid;

[0041] Considering a single-machine infinite system, it degenerates into a per-unit value.

[0042]

[0043] Z 2 =R 2+X 2 Generally considering that

[0044] X = 10R (4)

[0045] Combining equations (1), (3), and (4), we can obtain...

[0046] 1.01S 2 ((SCR-S) 2 -1)X 2 +(0.2P+2Q)u 2 Xu 4 =0 (5)

[0047] Solving

[0048]

[0049] The system impedance at full power and the infinite system voltage are calculated as follows:

[0050]

[0051] The method of formula (7) can simultaneously satisfy the requirements of reactive power balance construction and short-circuit ratio.

[0052] According to another aspect of the present invention, a new energy model testing system based on grid-side power optimization is also provided, comprising:

[0053] The parameter calculation module is used to calculate the voltage of the new energy grid-connected system units, the active power and reactive power generated by the new energy units after being equivalent to the power grid.

[0054] The parameter relationship analysis module is used to analyze the relationship between the terminal voltage of new energy generating units and active and reactive power.

[0055] The infinite power supply voltage calculation module is used to calculate the amplitude of the infinite power supply voltage based on the relationship between the terminal voltage of the new energy unit and the active and reactive power.

[0056] The infinite system voltage calculation module is used to obtain the short-circuit ratio of the i-terminal of the new energy unit based on the infinite power supply voltage amplitude, and to calculate the system impedance and infinite system voltage at full power.

[0057] Optionally, the module for calculating each parameter includes:

[0058] The extreme voltage calculation submodule is used to calculate the terminal voltage of new energy generating units based on infinite power supply voltage, line impedance, and line current.

[0059]

[0060] in, For the terminal voltage of new energy generating units, The voltage of the infinite power supply is... R is the line current. S X is the line resistance. S For line inductance;

[0061] The power calculation submodule is used to calculate the active and reactive power generated by the new energy generating units.

[0062] Assumption The apparent power delivered by the new energy unit to the infinite power source is calculated as follows:

[0063]

[0064] By separating the real part of apparent power (active power) and the imaginary part (reactive power), we obtain the expressions for active power and reactive power:

[0065]

[0066] Optionally, the parameter relationship analysis module includes:

[0067] The analysis parameter submodule is used to convert the expressions for active power and reactive power u... 2 Moving the term to the left side of the equation yields:

[0068]

[0069] Z 2 =R 2 +X 2 Substituting into the above equation and summing the squares of the active and reactive terms, we obtain the fourth-order equation for the terminal voltage:

[0070] u 4 -(2PR+2QX+E 2 )u 2 +Z 2 (P 2 +Q 2 )=0 (1)

[0071] Solving the equation yields the expression for the square of the terminal voltage:

[0072]

[0073] Taking the square root yields the voltage expression.

[0074]

[0075] Since the line resistance in a single-machine infinite bus system is often small and negligible, ignoring R, we can obtain:

[0076]

[0077] The voltage expression is derived as follows:

[0078]

[0079] Optionally, the module for calculating the infinite power supply voltage includes:

[0080] Moving the infinite power supply voltage term to the left side of the equation yields the relationship between the infinite power supply voltage and the transmission power.

[0081]

[0082] The method for calculating the voltage amplitude of an infinite power source is as follows:

[0083]

[0084] Optionally, the module for calculating the voltage of an infinite system includes:

[0085] The short-circuit ratio determination submodule is used to determine the short-circuit ratio at the i-terminal of the new energy unit based on the capacity-based short-circuit ratio index SCR-S:

[0086]

[0087] Where i and j represent new energy unit i and new energy unit j respectively, P REi and P REj U represents the active power injected by new energy unit i and new energy unit j, respectively. i and U j Z represents the terminal voltage of new energy unit i and new energy unit j. eq This is the equivalent impedance matrix of the AC power grid;

[0088] Considering a single-machine infinite system, it degenerates into a per-unit value.

[0089]

[0090] Z 2 =R 2 +X 2 Generally considering that

[0091] X = 10R (4)

[0092] Combining equations (1), (3), and (4), we can obtain...

[0093] 1.01S 2 ((SCR-S) 2 -1)X 2 +(0.2P+2Q)u 2 Xu 4=0 (5)

[0094] Solving

[0095]

[0096] The module for calculating the voltage of an infinite system is used to calculate the system impedance and the voltage of an infinite system at full power.

[0097]

[0098] The method of formula (7) can simultaneously satisfy the requirements of reactive power balance construction and short-circuit ratio.

[0099] Therefore, for scenarios with low short-circuit ratios in the system, the transmission power of renewable energy units can be increased by adjusting the grid-side voltage. First, a general analysis of the unit voltage, active power transmission, and reactive power transmission of the renewable energy grid-connected system after grid equivalence is required. Second, based on the general analysis, the relationship between the generator terminal voltage of the renewable energy units and the active power transmission, reactive power transmission, and grid-side power supply voltage can be derived. Finally, based on the above analysis, the relationship between the grid-side power supply voltage and the active power transmission can be obtained. Attached Figure Description

[0100] Exemplary embodiments of the present invention can be more fully understood by referring to the following figures:

[0101] Figure 1 This is a flowchart illustrating a new energy model testing method based on grid-side power optimization as described in this embodiment.

[0102] Figure 2 This is a schematic diagram of the single-machine infinite bus system described in this embodiment;

[0103] Figure 3 To keep all parameters except active power constant as described in this embodiment, a schematic diagram of the relationship between terminal voltage and active power of new energy transmission was drawn using MATLAB.

[0104] Figure 4 This is a schematic diagram of the simulation results of adjusting the infinite power supply voltage as described in this embodiment;

[0105] Figure 5 This is a schematic diagram of a new energy model testing system based on grid-side power optimization as described in this embodiment. Detailed Implementation

[0106] Exemplary embodiments of the invention will now be described with reference to the accompanying drawings. However, the invention may be embodied in many different forms and is not limited to the embodiments described herein. These embodiments are provided to fully and completely disclose the invention and to fully convey its scope to those skilled in the art. The terminology used in the exemplary embodiments illustrated in the drawings is not intended to limit the invention. In the drawings, the same units / elements are referred to by the same reference numerals.

[0107] Unless otherwise stated, the terms used herein (including technical terms) have their common meaning as understood by one of ordinary skill in the art. Furthermore, it is understood that terms defined in commonly used dictionaries should be understood to have a meaning consistent with the context of their relevant field, and not to be interpreted as having an idealized or overly formal meaning.

[0108] According to a first aspect of the present invention, a new energy model testing method 100 based on grid-side power optimization is provided, with reference to... Figure 1 As shown, the method 100 includes:

[0109] S101: Calculate the voltage of the new energy grid-connected system units, and the active and reactive power generated by the new energy units after being equivalent to the power grid.

[0110] S102: Analyze the relationship between the terminal voltage of new energy generating units and active and reactive power;

[0111] S103: Based on the relationship between the terminal voltage of the new energy generator unit and the active power and reactive power, calculate the amplitude of the infinite power supply voltage.

[0112] S104: Based on the infinite power supply voltage amplitude, obtain the short-circuit ratio of the i-terminal of the new energy unit, and calculate the system impedance and infinite system voltage at full power.

[0113] Specifically, refer to Figure 2 As shown, for scenarios with low short-circuit ratios in the system, the transmission power of renewable energy units is increased by adjusting the grid-side voltage. First, a general analysis of the unit voltage, active power transmission, and reactive power transmission of the renewable energy grid-connected system after grid equivalence is required. Second, based on the general analysis, the relationship between the generator terminal voltage of the renewable energy units and the active power transmission, reactive power transmission, and grid-side power supply voltage is derived. Finally, based on the above analysis, the relationship between the grid-side power supply voltage and the active power transmission is obtained.

[0114] (1) Calculate the terminal voltage of the new energy unit.

[0115] The terminal voltage of a new energy power generation unit can be obtained from the infinite power supply voltage, line impedance, and line current:

[0116]

[0117] in, For the terminal voltage of new energy generating units, The voltage of the infinite power supply is... R is the line current. S X is the line resistance. S This refers to the line inductance.

[0118] Calculate the active and reactive power generated by the new energy generating units.

[0119] Assumption The apparent power delivered by the new energy unit to the infinite power source can be calculated as follows:

[0120]

[0121] By separating the real part of apparent power (active power) and the imaginary part (reactive power), we can obtain the expressions for active power and reactive power:

[0122]

[0123] (3) Analyze the relationship between the terminal voltage of the new energy generator unit and the active power, reactive power and infinite power supply voltage.

[0124] Let u in the above equation 2 Moving the term to the left side of the equation yields:

[0125]

[0126] Z 2 =R 2 +X 2 Substituting into the above equation and summing the squares of the active and reactive terms, we obtain the fourth-order equation for the terminal voltage:

[0127] u 4 -(2PR+2QX+E 2 )u 2 +Z 2 (P 2 +Q 2 )=0 (1)

[0128] Solving the equation yields the expression for the square of the terminal voltage:

[0129]

[0130] Taking the square root yields the voltage expression (ignoring negative terms).

[0131]

[0132] Since the line resistance in a single-machine infinite bus system is often small and negligible, ignoring R, we can obtain:

[0133]

[0134] The voltage expression is derived as follows:

[0135]

[0136] Keeping all parameters except active power constant, the relationship between generator terminal voltage and active power transmission from renewable energy sources was plotted using MATLAB. (Refer to...) Figure 3 As shown.

[0137] (4) The relationship between infinite power supply voltage and new energy transmission power is derived.

[0138] Moving the infinite power supply voltage term to the left side of the equation yields the relationship between the infinite power supply voltage and the transmission power.

[0139]

[0140] Therefore, the method for calculating the amplitude of an infinite power supply voltage can be obtained as follows:

[0141]

[0142] (5) Currently, the commonly used electromechanical transient calculation software PSASP and PSD-BPA in China calculate the short-circuit ratio using the capacity-based short-circuit ratio index SCR-S. The short-circuit ratio at the i-terminal of new energy units is:

[0143]

[0144] Where i and j represent new energy unit i and new energy unit j respectively, PREi and PREj represent the active power injected by new energy unit i and new energy unit j respectively, Ui and Uj represent the terminal voltage of new energy unit i and new energy unit j, and Zeq is the equivalent impedance matrix of AC power grid.

[0145] Considering a single-machine infinite system, formula (2) can be degenerated into per-unit value as follows:

[0146]

[0147] Z 2 =R 2 +X 2 Generally considering that

[0148] X = 10R (4)

[0149] Combining equations (1), (3), and (4), we can obtain...

[0150] 1.01S 2 ((SCR-S) 2 -1)X 2 +(0.2P+2Q)u 2 Xu 4 =0 (5)

[0151] Solving

[0152]

[0153] The calculation methods for the system impedance and infinite system voltage under full power are as follows:

[0154]

[0155] Using formula (7) can simultaneously satisfy the requirements of reactive power balance construction and short-circuit ratio remaining unchanged.

[0156] Considering that directly supplying 1 pu would have a significant impact on the power grid, it is recommended to increase the active power slope limit in actual use, such as 1 pu / s or 0.5 pu / s.

[0157] Based on electromagnetic software, the relationship between the transmitted power and the infinite grid voltage when the short-circuit ratio (SCR) is 1.5 was studied. The simulation duration was 5 seconds, and the simulation step size was 0.01 seconds. The simulation results are as follows: Figure 4 As shown.

[0158] As can be seen from the figure: from t=0 to 2s, since the voltage of the infinite power supply is the same as that of the new energy generator, the power transmitted by the new energy generator to the infinite power grid is 0; starting from t=2s, the voltage of the infinite power supply gradually increases from 1 per unit value to 1.2 per unit value (t=4s). Under the active power slope limit (0.5pu / s), the active power transmitted by the new energy increases synchronously, gradually increasing from 0 per unit value to 1 per unit value (t=4s).

[0159] The simulation results show that increasing the infinite power supply voltage can improve the transmission power of new energy units. This verifies that adjusting the infinite power supply voltage can improve the transmission power of new energy units under a single-unit infinite power supply system with a low short-circuit ratio.

[0160] Therefore, for scenarios with low short-circuit ratios in the system, the transmission power of renewable energy units can be increased by adjusting the grid-side voltage. First, a general analysis of the unit voltage, active power transmission, and reactive power transmission of the renewable energy grid-connected system after grid equivalence is required. Second, based on the general analysis, the relationship between the generator terminal voltage of the renewable energy units and the active power transmission, reactive power transmission, and grid-side power supply voltage can be derived. Finally, based on the above analysis, the relationship between the grid-side power supply voltage and the active power transmission can be obtained.

[0161] Optionally, the calculation includes the voltage of the renewable energy grid-connected system units, and the active and reactive power generated by the renewable energy units after being equivalent to the grid, including:

[0162] Calculate the terminal voltage of the new energy unit based on the infinite power supply voltage, line impedance, and line current:

[0163]

[0164] in, For the terminal voltage of new energy generating units, The voltage of the infinite power supply is... R is the line current. S X is the line resistance. S For line inductance;

[0165] Calculate the active and reactive power generated by the new energy generating units:

[0166] Assumption The apparent power delivered by the new energy unit to the infinite power source is calculated as follows:

[0167]

[0168] By separating the real part of apparent power (active power) and the imaginary part (reactive power), we obtain the expressions for active power and reactive power:

[0169]

[0170] Optionally, the relationship between the terminal voltage of the new energy generating unit and its active and reactive power is analyzed, including:

[0171] The expressions for active power and reactive power u 2 Moving the term to the left side of the equation yields:

[0172]

[0173] Z 2 =R 2 +X 2 Substituting into the above equation and summing the squares of the active and reactive terms, we obtain the fourth-order equation for the terminal voltage:

[0174] u 4 -(2PR+2QX+E 2 )u 2 +Z 2 (P 2 +Q 2 )=0 (1)

[0175] Solving the equation yields the expression for the square of the terminal voltage:

[0176]

[0177] Taking the square root yields the voltage expression.

[0178]

[0179] Since the line resistance in a single-machine infinite bus system is often small and negligible, ignoring R, we can obtain:

[0180]

[0181] The voltage expression is derived as follows:

[0182]

[0183] Optionally, based on the relationship between the terminal voltage of the new energy unit and the active and reactive power, the amplitude of the infinite power supply voltage is calculated, including:

[0184] Moving the infinite power supply voltage term to the left side of the equation yields the relationship between the infinite power supply voltage and the transmission power.

[0185]

[0186] The method for calculating the voltage amplitude of an infinite power source is as follows:

[0187]

[0188] Optionally, based on the infinite power supply voltage amplitude, the short-circuit ratio at the i-terminal of the new energy unit is obtained, and the system impedance and infinite system voltage at full power are calculated, including:

[0189] Based on the short-circuit ratio index SCR-S of capacity, the short-circuit ratio of the i-terminal of the new energy unit is determined as follows:

[0190]

[0191] Where i and j represent new energy unit i and new energy unit j respectively, P REi and P REj U represents the active power injected by new energy unit i and new energy unit j, respectively. i and U j Z represents the terminal voltage of new energy unit i and new energy unit j. eq This is the equivalent impedance matrix of the AC power grid;

[0192] Considering a single-machine infinite system, it degenerates into a per-unit value.

[0193]

[0194] Z 2 =R 2+X 2 Generally considering that

[0195] X = 10R (4)

[0196] Combining equations (1), (3), and (4), we can obtain...

[0197] 1.01S 2 ((SCR-S) 2 -1)X 2 +(0.2P+2Q)u 2 Xu 4 =0 (5)

[0198] Solving

[0199]

[0200] The system impedance at full power and the infinite system voltage are calculated as follows:

[0201]

[0202] The method of formula (7) can simultaneously satisfy the requirements of reactive power balance construction and short-circuit ratio.

[0203] Therefore, for scenarios with low short-circuit ratios in the system, the transmission power of renewable energy units can be increased by adjusting the grid-side voltage. First, a general analysis of the unit voltage, active power transmission, and reactive power transmission of the renewable energy grid-connected system after grid equivalence is required. Second, based on the general analysis, the relationship between the generator terminal voltage of the renewable energy units and the active power transmission, reactive power transmission, and grid-side power supply voltage can be derived. Finally, based on the above analysis, the relationship between the grid-side power supply voltage and the active power transmission can be obtained.

[0204] According to another aspect of the present invention, a new energy model testing system 500 based on grid-side power optimization is also provided, with reference to... Figure 5 As shown, the system 500 includes:

[0205] The parameter calculation module 510 is used to calculate the voltage of the new energy grid-connected system units, the active power and reactive power generated by the new energy units after being equivalent to the power grid.

[0206] The parameter relationship analysis module 520 is used to analyze the relationship between the terminal voltage of new energy generator units and active power and reactive power.

[0207] The infinite power supply voltage calculation module 530 is used to calculate the amplitude of the infinite power supply voltage based on the relationship between the terminal voltage of the new energy unit and the active power and reactive power.

[0208] The infinite system voltage calculation module 540 is used to obtain the short-circuit ratio of the i-terminal of the new energy unit based on the infinite power supply voltage amplitude, and to calculate the system impedance and infinite system voltage at full power.

[0209] Optionally, the module for calculating each parameter includes:

[0210] The extreme voltage calculation submodule is used to calculate the terminal voltage of new energy generating units based on infinite power supply voltage, line impedance, and line current.

[0211]

[0212] in, For the terminal voltage of new energy generating units, The voltage of the infinite power supply is... R is the line current. S X is the line resistance. S For line inductance;

[0213] The power calculation submodule is used to calculate the active and reactive power generated by the new energy generating units.

[0214] Assumption The apparent power delivered by the new energy unit to the infinite power source is calculated as follows:

[0215]

[0216] By separating the real part of apparent power (active power) and the imaginary part (reactive power), we obtain the expressions for active power and reactive power:

[0217]

[0218] Optionally, the parameter relationship analysis module includes:

[0219] The analysis parameter submodule is used to convert the expressions for active power and reactive power u... 2 Moving the term to the left side of the equation yields:

[0220]

[0221] Z 2 =R 2 +X 2 Substituting into the above equation and summing the squares of the active and reactive terms, we obtain the fourth-order equation for the terminal voltage:

[0222] u 4 -(2PR+2QX+E 2 )u 2 +Z 2 (P 2 +Q 2)=0 (1)

[0223] Solving the equation yields the expression for the square of the terminal voltage:

[0224]

[0225] Taking the square root yields the voltage expression.

[0226]

[0227] Since the line resistance in a single-machine infinite bus system is often small and negligible, ignoring R, we can obtain:

[0228]

[0229] The voltage expression is derived as follows:

[0230]

[0231] Optionally, the module for calculating the infinite power supply voltage includes:

[0232] Moving the infinite power supply voltage term to the left side of the equation yields the relationship between the infinite power supply voltage and the transmission power.

[0233]

[0234] The method for calculating the voltage amplitude of an infinite power source is as follows:

[0235]

[0236] Optionally, the module for calculating the voltage of an infinite system includes:

[0237] The short-circuit ratio determination submodule is used to determine the short-circuit ratio at the i-terminal of the new energy unit based on the capacity-based short-circuit ratio index SCR-S:

[0238]

[0239] Where i and j represent new energy unit i and new energy unit j respectively, P REi and P REj U represents the active power injected by new energy unit i and new energy unit j, respectively. i and U j Z represents the terminal voltage of new energy unit i and new energy unit j. eq This is the equivalent impedance matrix of the AC power grid;

[0240] Considering a single-machine infinite system, it degenerates into a per-unit value.

[0241]

[0242] Z 2 =R 2 +X 2 Generally considering that

[0243] X = 10R (4)

[0244] Combining equations (1), (3), and (4), we can obtain...

[0245] 1.01S 2 ((SCR-S) 2 -1)X 2 +(0.2P+2Q)u 2 Xu 4 =0 (5)

[0246] Solving

[0247]

[0248] The module for calculating the voltage of an infinite system is used to calculate the system impedance and the voltage of an infinite system at full power.

[0249]

[0250] The method of formula (7) can simultaneously satisfy the requirements of reactive power balance construction and short-circuit ratio.

[0251] The new energy model testing system 500 based on grid-side power optimization in one embodiment of the present invention corresponds to the new energy model testing method 100 based on grid-side power optimization in another embodiment of the present invention, and will not be described again here.

[0252] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code. The solutions in the embodiments of this application can be implemented in various computer languages, such as the object-oriented programming language Java and the interpreted scripting language JavaScript.

[0253] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0254] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0255] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0256] Although preferred embodiments of this application have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of this application.

[0257] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the spirit and scope of this application. Therefore, if such modifications and variations fall within the scope of the claims of this application and their equivalents, this application also intends to include such modifications and variations.

Claims

1. A test method for a new energy model based on grid-side power source optimization, characterized in that, include: Calculate the voltage of the new energy grid-connected system units, and the active and reactive power generated by the new energy units after being equivalent to the power grid. Analyze the relationship between the terminal voltage of new energy generating units and active and reactive power; Based on the relationship between the terminal voltage of the new energy generator unit and the active and reactive power, the amplitude of the infinite power supply voltage is calculated. Based on the infinite power supply voltage amplitude, the short-circuit ratio of the i-terminal of the new energy unit is obtained, and the system impedance and infinite system voltage under full power are calculated.

2. The method according to claim 1, characterized in that, The calculation includes the voltage of the generating units in the renewable energy grid-connected system after grid equivalence, and the active and reactive power generated by the renewable energy generating units, including: Calculate the terminal voltage of the new energy unit based on the infinite power supply voltage, line impedance, and line current: in, For the terminal voltage of new energy generating units, The voltage of the power supply is infinite. R is the line current. S X is the line resistance. S For line inductance; Calculate the active and reactive power generated by the new energy generating units: Assumption The apparent power delivered by the new energy unit to the infinite power source is calculated as follows: By separating the real part of apparent power (active power) and the imaginary part (reactive power), we obtain the expressions for active power and reactive power:

3. The method according to claim 2, characterized in that, Analysis of the relationship between the terminal voltage of new energy generating units and active and reactive power, including: The expressions for active power and reactive power u 2 Moving the term to the left side of the equation yields: Z 2 =R 2 +X 2 Substituting into the above equation and summing the squares of the active and reactive terms, we obtain the fourth-order equation for the terminal voltage: u 4 -(2PR+2QX+E 2 )u 2 +Z 2 (P 2 +Q 2 )=0 (1) Solving the equation yields the expression for the square of the terminal voltage: Taking the square root yields the voltage expression. Since the line resistance in a single-machine infinite bus system is often small and negligible, ignoring R, we can obtain: The voltage expression is derived as follows:

4. The method according to claim 3, characterized in that, Based on the relationship between the terminal voltage of the new energy unit and its active and reactive power, the amplitude of the infinite power supply voltage is calculated, including: Moving the infinite power supply voltage term to the left side of the equation yields the relationship between the infinite power supply voltage and the transmission power. The method for calculating the amplitude of an infinite power supply voltage is as follows:

5. The method according to claim 4, characterized in that, Based on the infinite power supply voltage amplitude, the short-circuit ratio at the i-terminal of the new energy unit is obtained, and the system impedance and infinite system voltage at full power are calculated, including: Based on the short-circuit ratio index SCR-S of capacity, the short-circuit ratio of the i-terminal of the new energy unit is determined as follows: Where i and j represent new energy unit i and new energy unit j respectively, P REi and P REj U represents the active power injected by new energy unit i and new energy unit j, respectively. i and U j Z represents the terminal voltage of new energy unit i and new energy unit j. eq This is the equivalent impedance matrix of the AC power grid; Considering a single-machine infinite system, it degenerates into a per-unit value. Z 2 =R 2 +X 2 Generally considering that X = 10R (4) Combining equations (1), (3), and (4), we can obtain... 1.01S 2 ((SCR-S) 2 -1)X 2 +(0.2P+2Q)u 2 X-u 4 =0 (5) Solving The system impedance at full power and the infinite system voltage are calculated as follows: The method of formula (7) can simultaneously satisfy the requirements of reactive power balance construction and short-circuit ratio.

6. A new energy model testing system based on grid-side power supply optimization, characterized in that, include: The parameter calculation module is used to calculate the voltage of the new energy grid-connected system units, the active power and reactive power generated by the new energy units after being equivalent to the power grid. The parameter relationship analysis module is used to analyze the relationship between the terminal voltage of new energy generating units and active and reactive power. The infinite power supply voltage calculation module is used to calculate the amplitude of the infinite power supply voltage based on the relationship between the terminal voltage of the new energy unit and the active and reactive power. The infinite system voltage calculation module is used to obtain the short-circuit ratio of the i-terminal of the new energy unit based on the infinite power supply voltage amplitude, and to calculate the system impedance and infinite system voltage at full power.

7. The system according to claim 6, characterized in that, The module for calculating each parameter includes: The extreme voltage calculation submodule is used to calculate the terminal voltage of new energy generating units based on infinite power supply voltage, line impedance, and line current. in, For the terminal voltage of new energy generating units, The voltage of the power supply is infinite. R is the line current. S X is the line resistance. S For line inductance; The power calculation submodule is used to calculate the active and reactive power generated by the new energy generating units. Assumption The apparent power delivered by the new energy unit to the infinite power source is calculated as follows: By separating the real part of apparent power (active power) and the imaginary part (reactive power), we obtain the expressions for active power and reactive power:

8. The system according to claim 7, characterized in that, The module for analyzing parameter relationships includes: The analysis parameter submodule is used to convert the expressions for active power and reactive power u... 2 Moving the term to the left side of the equation yields: Z 2 =R 2 +X 2 Substituting into the above equation and summing the squares of the active and reactive terms, we obtain the fourth-order equation for the terminal voltage: u 4 -(2PR+2QX+E 2 )u 2 +Z 2 (P 2 +Q 2 )=0 (1) Solving the equation yields the expression for the square of the terminal voltage: Taking the square root yields the voltage expression. Since the line resistance in a single-machine infinite bus system is often small and negligible, ignoring R, we can obtain: The voltage expression is derived as follows:

9. The system according to claim 8, characterized in that, The module for calculating infinite power supply voltage includes: Moving the infinite power supply voltage term to the left side of the equation yields the relationship between the infinite power supply voltage and the transmission power. The method for calculating the amplitude of an infinite power supply voltage is as follows:

10. The system according to claim 9, characterized in that, The module for calculating the voltage of an infinite system includes: The short-circuit ratio determination submodule is used to determine the short-circuit ratio at the i-terminal of the new energy unit based on the capacity-based short-circuit ratio index SCR-S: Where i and j represent new energy unit i and new energy unit j respectively, P REi and P REj U represents the active power injected by new energy unit i and new energy unit j, respectively. i and U j Z represents the terminal voltage of new energy unit i and new energy unit j. eq This is the equivalent impedance matrix of the AC power grid; Considering a single-machine infinite system, it degenerates into a per-unit value. Z 2 =R 2 +X 2 Generally considering that X = 10R (4) Combining equations (1), (3), and (4), we can obtain... 1.01S 2 ((SCR-S) 2 -1)X 2 +(0.2P+2Q)u 2 X-u 4 =0 (5) Solving The module for calculating the voltage of an infinite system is used to calculate the system impedance and the voltage of an infinite system at full power. The method of formula (7) can simultaneously satisfy the requirements of reactive power balance construction and short-circuit ratio.

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