CN116316779A - Configuration method and device of flexible power transformer - Google Patents

Abstract

The invention discloses a configuration method and a device of a flexible power transformer, and relates to the technical field of power systems, wherein the method comprises the following steps: after determining that the power system is suitable for configuring a flexible power transformer according to the collected power system data, calculating the short-circuit ratio of each new energy multi-station; for each new energy station with the new energy multi-station short-circuit ratio not greater than a first preset threshold value: sequentially accessing the flexible power transformers according to the sequence from small to large of the flexible power transformers, recalculating the short-circuit ratio of the new energy multi-station, and determining configuration parameters of the new energy multi-station accessing the flexible power transformers when the recalculated short-circuit ratio of the new energy multi-station is larger than a first preset threshold value; and screening the configuration parameters of the flexible power transformer accessed to each new energy station by utilizing the overcurrent threshold and the withstand voltage threshold to obtain the configuration parameters of the flexible power transformer of the power system. The invention can deploy a proper flexible power transformer for the power system and improve the new energy output capability.

Description

Configuration method and device of flexible power transformer

technical field

The invention relates to the technical field of power systems, in particular to a configuration method and device for a flexible power transformer.

Background technique

This section is intended to provide a background or context to embodiments of the invention that are recited in the claims. The descriptions herein are not admitted to be prior art by inclusion in this section.

With the integration of large-scale new energy into the power grid, the successive commissioning of UHV AC and DC transmission projects, and the gradual withdrawal of conventional thermal power units, the form of the power grid has undergone profound changes, and the difficulty of power grid voltage regulation and power flow control has become increasingly difficult. In terms of transient state, large-scale new energy transmits power through long-distance AC and DC. When the power grid fails, the dynamic reactive power support capacity in the near area is insufficient. grid, thus further aggravating the voltage rise, and eventually leading to large-scale wind turbines and photovoltaic chains going off-grid. In terms of steady state, due to the influence of a large number of new energy sources connected to terminal substations, when the power sent out by new energy stations is large, it is easy to cause low voltage problems. The voltage fluctuation rate of multiple substations has repeatedly exceeded the standard, which seriously affects the regional power supply. quality. Therefore, the fluctuation of new energy output, the large-scale replacement of conventional power by new energy, the rapid and frequent changes in power and voltage caused by changes in the grid structure, and the high/low voltage limit, etc., limit the consumption of new energy by the grid. Therefore, there is an urgent need to improve the operation regulation capacity of the power grid.

Due to the combination of power electronics technology and the advantages of conventional electromagnetic transformers, flexible power transformers can use small-capacity converters to realize rapid, continuous and precise adjustment of power transformer voltages, improve the ability of new power systems to absorb new energy, and ensure the reliability of power grids run. Therefore, it is necessary to propose a flexible power transformer configuration method suitable for the new energy station side.

At present, the research on flexible power transformers at home and abroad basically focuses on the principle analysis of simplified circuits, and there are few related developments on test prototypes. In order to better solve the problems of low voltage and overvoltage in power systems, it is necessary to propose a flexible The configuration method of power transformers is used to deploy suitable flexible power transformers according to application scenarios and demand analysis.

Contents of the invention

The embodiment of the present invention provides a flexible power transformer configuration method, which is used to determine the appropriate flexible power transformer configuration parameters in the planning and design stage, deploy a suitable flexible power transformer for the power system, improve the ability to send out new energy, and improve the operation and regulation ability of the power grid , the method includes:

Collect power system data; the power system data includes the short-circuit capacity of the power system and the installed capacity of multiple new energy stations in the power system;

According to the short-circuit capacity of the power system and the installed capacity of multiple new energy stations in the power system, after determining that the power system is suitable for configuring flexible power transformers, calculate the new energy multi-site short-circuit ratio of each new energy station in the power system;

For each new energy station whose short-circuit ratio is not greater than the first preset threshold: according to the order of the capacity of the flexible power transformer from small to large, connect the flexible power transformer in turn, after connecting the flexible power transformer each time Recalculate the new energy multi-station short-circuit ratio of the new energy station, and when the recalculated new energy multi-station short-circuit ratio of the new energy station is greater than the first preset threshold, determine the configuration of the new energy station connected to the flexible power transformer parameters; the configuration parameters include the type and access position of the flexible power transformer;

Using the overcurrent threshold and withstand voltage threshold of the flexible power transformer, the configuration parameters of the flexible power transformer connected to each new energy station are screened to obtain the configuration parameters of the flexible power transformer in the power system.

The embodiment of the present invention also provides a flexible power transformer configuration device, which is used to determine the appropriate flexible power transformer configuration parameters in the planning and design stage, deploy a suitable flexible power transformer for the power system, improve the ability to send new energy, and improve the operation and regulation of the power grid capabilities, the device includes:

The data collection module is used to collect power system data; the power system data includes the short-circuit capacity of the power system and the installed capacity of multiple new energy stations in the power system;

The configuration preparation module is used to calculate the new energy capacity of each new energy station in the power system after determining that the power system is suitable for configuring flexible power transformers according to the short-circuit capacity of the power system and the installed capacity of multiple new energy stations in the power system. Station short circuit ratio;

The flexible power transformer configuration determination module is used for each new energy station whose short-circuit ratio of new energy multi-site stations is not greater than the first preset threshold: connect the flexible power transformers sequentially according to the order of the capacity of the flexible power transformers from small to large, Recalculate the new energy multi-station short-circuit ratio of the new energy station every time the flexible power transformer is connected. When the recalculated new energy multi-station short-circuit ratio of the new energy station is greater than the first preset threshold, determine the new energy The configuration parameters of the station access to the flexible power transformer; the configuration parameters include the type and access location of the flexible power transformer;

The flexible power transformer configuration screening module is used to screen the configuration parameters of each new energy station connected to the flexible power transformer by using the overcurrent threshold and withstand voltage threshold of the flexible power transformer, and obtain the configuration parameters of the flexible power transformer of the power system.

The embodiment of the present invention also provides a computer device, including a memory, a processor, and a computer program stored on the memory and operable on the processor, and the processor implements the configuration method of the above-mentioned flexible power transformer when executing the computer program .

The embodiment of the present invention also provides a computer-readable storage medium, the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the above-mentioned method for configuring the flexible power transformer is implemented.

The embodiment of the present invention also provides a computer program product, the computer program product includes a computer program, and when the computer program is executed by a processor, the above-mentioned method for configuring the flexible power transformer is realized.

In the embodiment of the present invention, the power system data is first collected, and the short-circuit capacity of the power system in the power system data and the installed capacity of multiple new energy stations in the power system are used to judge whether the power system is suitable for configuring flexible power transformers; when it is determined that the power system is suitable for Configure flexible power transformers to calculate the short-circuit ratio of each new energy multi-site station; when the new energy multi-site short-circuit ratio meets the conditions, that is, when it is less than or equal to the first preset threshold, connect the flexible power transformer to the new energy station; When selecting the flexible power transformer to be connected to the new energy station, connect it in order according to the capacity of the flexible power transformer from small to large, and recalculate the new energy multi-site short circuit of the new energy station after each connection of the flexible power transformer ratio, when the recalculated new energy multi-station short-circuit ratio of the new energy station is greater than the first preset threshold, determine the configuration parameters of the new energy station connected to the flexible power transformer; finally use the overcurrent threshold and the withstand voltage of the flexible power transformer The voltage threshold value is used to screen the configuration parameters of the flexible power transformers connected to each new energy station to obtain the configuration parameters of the flexible power transformers of the power system, thereby obtaining the configuration scheme of the flexible power transformers of the power system. The embodiment of the present invention realizes the determination of the configuration parameters of the connected flexible power transformer through the short circuit ratio of new energy multi-site stations, and screens the configuration parameters through the overcurrent threshold and withstand voltage threshold of the flexible power transformer, which can be used in the planning and design stage for new Deploying suitable flexible power transformers in energy stations has improved the ability to send new energy and improve the ability to regulate grid operation.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only These are some embodiments of the present invention. Those skilled in the art can also obtain other drawings based on these drawings without creative work. In the attached picture:

Fig. 1 is a schematic flow chart of a method for configuring a flexible power transformer in an embodiment of the present invention;

Fig. 2 is a topological diagram of sending large-scale new energy through an AC transmission line in an embodiment of the present invention;

3 is a schematic diagram of a power system connected to a flexible power transformer in an embodiment of the present invention;

Fig. 4 is a specific example diagram of the configuration method of the flexible power transformer in the embodiment of the present invention;

Fig. 5 is a schematic diagram of a configuration device of a flexible power transformer in an embodiment of the present invention.

Detailed ways

In order to make the purpose, technical solutions and advantages of the embodiments of the present invention more clear, the embodiments of the present invention will be further described in detail below in conjunction with the accompanying drawings. Here, the exemplary embodiments and descriptions of the present invention are used to explain the present invention, but not to limit the present invention.

First, technical terms involved in the embodiments of the present invention are explained.

Flexible power transformer: Combining the active part of power electronics with a conventional electromagnetic transformer to realize rapid, continuous and precise adjustment of the voltage of the AC power transformer, improve the ability of the new power system to absorb new energy, and ensure the reliable operation of the power grid. The flexible power transformer of the general distribution network voltage level is composed of a three-winding power transformer with compensation winding and a voltage source inverter. voltage regulation service. Flexible power transformers used at high voltage levels generally use a series transformer connected in series on the neutral point side of the winding that connects the transformer to the new energy station, and then connect the secondary side of the series transformer to the voltage source inverter , during operation, the voltage source inverter and series transformer provide voltage components with controllable amplitude and direction for the primary winding of the power transformer, so as to improve the grid-connected voltage of the new energy station.

New energy multi-station short-circuit ratio: It can reflect the voltage support strength of new energy grid-connected points, and effectively guide the development and operation of power grids and new energy. The multi-site short-circuit ratio of the step-up transformer low-voltage side of the new energy power generation unit should not be lower than 1.5, and the multi-site short-circuit ratio of the new energy grid-connected point should not be lower than 2.0, preferably higher than 3.0.

The applicant found that due to the combination of power electronics technology and the advantages of conventional electromagnetic transformers, the flexible power transformer can use a small-capacity converter to realize rapid, continuous and precise adjustment of the power transformer voltage, and improve the ability of the new power system to absorb new energy. To ensure the reliable operation of the power grid, it is necessary to propose a flexible power transformer configuration method suitable for the new energy station side. However, the research on flexible power transformers at home and abroad is basically based on the principle analysis of simplified circuits, and there are few related developments on test prototypes. In order to better solve the problems of low voltage and overvoltage in power systems, it is necessary to propose a flexible power transformer. Transformer configuration methods to deploy suitable flexible power transformers according to application scenarios and demand analysis. For this reason, the applicant proposes a method for configuring a flexible power transformer.

Fig. 1 is a schematic flowchart of a method for configuring a flexible power transformer in an embodiment of the present invention. As shown in Fig. 1, the method includes:

Step 101, collecting power system data; the power system data includes the short-circuit capacity of the power system and the installed capacity of multiple new energy stations in the power system;

Step 102. According to the short-circuit capacity of the power system and the installed capacity of multiple new energy stations in the power system, after determining that the power system is suitable for configuring flexible power transformers, calculate the new energy multi-site short circuit of each new energy station in the power system Compare;

Step 103. For each new energy station whose short-circuit ratio is not greater than the first preset threshold: according to the order of the capacity of the flexible power transformer from small to large, connect the flexible power transformer in sequence, and connect the flexible power transformer each time. After the power transformer, recalculate the new energy multi-station short-circuit ratio of the new energy station. When the recalculated new energy multi-station short-circuit ratio of the new energy station is greater than the first preset threshold, it is determined that the new energy station is connected to flexible power. Transformer configuration parameters;

Step 104: Use the overcurrent threshold and withstand voltage threshold of the flexible power transformer to screen the configuration parameters of each new energy station connected to the flexible power transformer to obtain the configuration parameters of the flexible power transformer in the power system.

It can be seen from the process shown in Figure 1 that the embodiment of the present invention realizes the determination of the configuration parameters of the connected flexible power transformer through the short-circuit ratio of new energy multi-site stations, and configures the parameters through the overcurrent threshold and withstand voltage threshold of the flexible power transformer Through screening, suitable flexible power transformers can be deployed for new energy stations in the planning and design stage, which improves the ability to send new energy and improve the ability to regulate grid operation.

The embodiments of the present invention are explained in detail below.

Start by collecting power system data. Fig. 2 is a topological diagram of large-scale new energy sent through AC transmission lines in the embodiment of the present invention. As shown in Fig. 2, the power system includes multiple new energy stations. New energy stations can constitute a new energy equivalent system. The power system data includes the short-circuit capacity S _ac of the power system, the set of installed capacities of multiple new energy stations in the power system S={S ₁ ,S ₂ ,. ..,S _m }, the impedance matrix Z of the power system, the active power set P={P ₁ ,P ₂ ,...,P _m } of each new energy station input to the grid, and the output side voltage of each new energy station Set U={U ₁ , U ₂ ,...,U _m }, where m represents the number of new energy stations in the power system, S _m , P _m , and U _m are the Installed capacity, active power input to the grid, and output side voltage. In addition, the model and parameters of the flexible power transformer to be connected to the new energy station can be obtained in advance. It should be noted that the power system data is not limited to the above data, which is not limited here and is only used as an example.

Then, according to the collected power system data, it is judged whether the power system is suitable for configuring flexible power transformers. During implementation, it can be judged whether the power system is suitable for configuring flexible power transformers according to the short-circuit ratio of the power system.

In one embodiment, in step 102, according to the short-circuit capacity of the power system and the installed capacity of multiple new energy stations in the power system, it is determined that the power system is suitable for configuring a flexible power transformer, which may include:

According to the short-circuit capacity of the power system and the installed capacity of multiple new energy stations in the power system, the short-circuit ratio of the power system is calculated; when the short-circuit ratio of the power system is less than or equal to the second preset threshold, it is determined that the power system is suitable for configuring flexible power transformers.

In the specific implementation, the first step, referring to Fig. 2, calculates the short-circuit ratio SCR of the power system according to the following formula according to the short-circuit capacity S _ac of the power system and the set S of installed capacities of multiple new energy stations in the power system:

S_g为新能源等效额定容量，其中U₀为新能源场站并网点处的电压，Z₀为新能源场站并网点处的阻抗。In the above formula, the short-circuit capacity of the power system

S _g is the equivalent rated capacity of new energy, where U ₀ is the voltage at the grid connection point of the new energy station, and Z ₀ is the impedance at the grid connection point of the new energy station.

In the second step, the power system short _circuit ratio SCR is compared with a second preset threshold SCR ₀ , which is used to characterize the strength of the power system and can be set to 2.0 to 3.0, preferably 3.0. When the power system short-circuit ratio SCR is greater than or equal to the second preset threshold SCR ₀ , indicating that the power system is relatively strong or strong, then it is determined that the power system is not suitable for configuring flexible power transformers; when the power system short-circuit ratio SCR is less than the second preset The threshold SCR ₀ is set to indicate that the power system is a weak system, so it is determined that the power system is suitable for configuring a flexible power transformer. In this example, before configuring the flexible power transformer for the power system, it is first judged whether it is suitable to configure the flexible power transformer, which can improve the deployment efficiency of the flexible power transformer in the power system.

When it is determined that the power system is suitable for configuring flexible power transformers, the appropriate flexible power transformer configuration parameters are determined according to the short-circuit ratio of new energy multi-site stations.

In one embodiment, the new energy multi-station short-circuit ratio of the new energy station is calculated according to the following formula:

Among them, MRSCR _i is the new energy multi-station short-circuit ratio of the i-th new energy station, S _aci is the system short-circuit capacity at the i-th new energy station; P _i is the input power of the i-th new energy station Active power, P _j is the active power of the j-th new energy station input to the grid, Z _eqij is the mutual impedance between the i-th new energy station and the j-th new energy station, Z _eqii is the i-th new energy station The self-impedance of the energy station, n is the number of new energy stations, and j is an integer.

During implementation, calculate the new energy multi-station short-circuit ratio for each new energy station in the power system, and compare the new energy multi-station short-circuit ratio of each new energy station with the first preset threshold; when a new energy When the new energy multi-station short-circuit ratio of the station is greater than the first preset threshold, it is considered that the power system can quickly absorb new energy and the power grid operates reliably. At this time, there is no need to configure a flexible power transformer for the new energy station; if a When the new energy multi-station short-circuit ratio of the new energy station is less than or equal to the first preset threshold, it is considered that the grid operation adjustment capability and the ability to absorb new energy need to be improved. At this time, it is necessary to configure flexible power transformer. Wherein, the first preset threshold can be set to 1.5 to 2.5, preferably 1.5.

When selecting the flexible power transformer connected to the new energy station in the planning stage, according to the existing flexible power transformer data, the parameters such as the model and capacity of the flexible power transformer can be known, and the appropriate backup for the power system to be connected to the new energy station can be selected. When choosing a flexible power transformer, it should be noted that the capacities of flexible power transformers with inconsistent models may be the same.

During specific implementation, for each new energy station whose short-circuit ratio is not greater than the first preset threshold value: according to the order of the capacity of the flexible power transformer from small to large, the flexible power transformer is connected in turn, and each time it is connected After the flexible power transformer recalculates the new energy multi-station short-circuit ratio of the new energy station, when the recalculated new energy multi-station short-circuit ratio of the new energy station is greater than the first preset threshold, it is determined that the new energy station at this time If the power grid operation adjustment ability is accurate, the response is fast, and the operation is reliable, it is judged that the flexible power transformer connected at this time is suitable, and then the configuration parameters of the new energy station connected to the flexible power transformer are determined.

Fig. 3 is a schematic diagram of a power system connected to a flexible power transformer in an embodiment of the present invention. The large dotted frame in Fig. 3 is a flexible power transformer, and the flexible power transformer consists of a three-winding power transformer (small dotted frame) with a compensation winding and a voltage Composed of source inverters. For each new energy station that needs to be connected to a flexible power transformer, it is deployed in the same way, and the configuration parameters of each new energy station connected to the flexible power transformer can be obtained. The configuration parameters can include the model of the flexible power transformer and the location of the connection. and other information.

In the embodiment of the present invention, the connection positions of the flexible power transformer can include voltage levels of 220/35kV, 110/35kV, 110/10kV, 66/10kV, etc., which have a wide range of applications. Different access locations have different requirements for the withstand voltage level, overcurrent capability, overload capability, and capacity of the switching tube of the flexible power transformer. In the embodiment of the present invention, an appropriate access location can be selected in the planning stage, and the energy can reflect the flexible power transformer. The switching tube withstand voltage level, over-current capacity, overload capacity and other network-related characteristics.

After obtaining the configuration parameters of flexible power transformers connected to each new energy station, the configuration scheme of flexible power transformers in the power system can be generated. However, in order to improve the reliability of access to flexible power transformers, in the embodiment of the present invention, the overcurrent threshold and voltage withstand threshold of flexible power transformers are used to screen the configuration parameters of each new energy station connected to flexible power transformers, and the The flexible power transformers that do not meet the conditions can be removed, and the configuration parameters of the flexible power transformers connected to the new energy stations with high reliability can be obtained, that is, the configuration parameters of the flexible power transformers of the high-reliability power system can be obtained, thereby determining the final Configuration scheme of flexible power transformer for power system.

In one embodiment, the overcurrent threshold of the flexible power transformer is obtained according to the following formula:

I _o ＝k ₁ ×I _N

Among them, I _o is the over-current threshold of the flexible power transformer, k ₁ is the over-current coefficient, and I _N is the rated current of the flexible power transformer.

In one embodiment, the withstand voltage threshold of the flexible power transformer is obtained according to the following formula:

ΔU _o =(k ₂ -1)×U _N

Among them, ΔU _o is the withstand voltage threshold of the flexible power transformer, k ₂ is the withstand voltage coefficient, and U _N is the rated voltage of the flexible power transformer.

In order to improve the reliability of connecting flexible power transformers, in one embodiment, the configuration parameters of each new energy station connected to flexible power transformers are screened by using the overcurrent threshold and withstand voltage threshold of flexible power transformers to obtain the power system The configuration parameters of the flexible power transformer can include:

Calculate the single-phase ground fault short-circuit current of the high-voltage side outlet of the flexible power transformer connected to each new energy station. When the single-phase ground fault short-circuit current of the high-voltage side outlet of the flexible power transformer connected to any new energy station is greater than the The overcurrent threshold of the transformer removes the flexible power transformer for the new energy station;

Calculate the overvoltage of the new energy machine terminal with a single-phase ground fault at the outlet of the high-voltage side of the flexible power transformer connected to each new energy station. If the terminal overvoltage is greater than the withstand voltage threshold of the flexible power transformer, the flexible power transformer is removed for the new energy site.

During implementation, the single-phase ground fault short-circuit current I of the high-voltage side outlet of the flexible power transformer connected to the new energy station is calculated according to the following formula:

为型号为T_i的柔性电力变压器阻抗，/>

为与型号T_i的柔性电力变压器低压侧相连的线路L_i的阻抗，U_i为第i个新能源场机端电压。in,

is the impedance of the flexible power transformer whose type is T _i , />

is the impedance of the line L _i connected to the low-voltage side of the flexible power transformer of type T _i , and U _i is the terminal voltage of the i-th new energy field.

During implementation, the overvoltage ΔU of the new energy machine terminal for single-phase ground fault at the high-voltage side outlet of the flexible power transformer connected to the new energy station is calculated according to the following formula:

Among them, E is the equivalent potential of the AC system, U _N is the nominal voltage, and MRSCR _i is the new energy multi-station short-circuit ratio of the i-th new energy station.

Fig. 4 is a diagram of a specific example of the configuration method of the flexible power transformer in the embodiment of the present invention. As shown in Fig. 4, the method includes:

1. The input impedance matrix Z, the set of installed capacities of new energy stations S={S ₁ ,S ₂ ,...,S _m }, the set of active power input to the power grid of each new energy station P={P ₁ , P ₂ ,...,P _m }, output side voltage (each node) set of each new energy station U={U ₁ ,U ₂ ,...,U _m }, first threshold SCR ₀ , second threshold MRSCR ₀ , flexible power transformer overcurrent threshold I _o , flexible power transformer withstand voltage threshold ΔU _o ;

2. Calculate the short circuit ratio SCR of the power system;

3. When the power system short-circuit ratio SCR>SCR ₀ , it is determined that the power system is not suitable for configuring flexible power transformers;

4. When the power system short-circuit ratio SCR≤SCR ₀ , calculate the new energy multi-station short-circuit ratio MRSCR for each new energy station;

5. Compare the new energy multi-station short-circuit ratio MRSCR of each new energy station with the second threshold MRSCR _0. MRSCR ₀ is preferably 1.5. When MRSCR>MRSCR ₀ , it is determined that the new energy station is not suitable for configuring flexible power transformers ; When MRSCR≤MRSCR ₀ , connect the flexible power transformer to the new energy station;

6. Recalculate the new energy multi-station short-circuit ratio of the new energy station connected to the flexible power transformer. When the new energy multi-station short-circuit ratio of the new energy station connected to the flexible power transformer is greater than MRSCR ₀ , it is considered that the flexible power The transformer connection is suitable, and the configuration parameters of the flexible power transformer connected to the new energy station are determined;

7. Calculate the single-phase ground fault short-circuit current I of the high-voltage side outlet of the flexible power transformer connected to each new energy station. I is greater than the overcurrent threshold I _o of the flexible power transformer, and the flexible power transformer is removed for the new energy station;

8. Calculate the single-phase grounding fault at the high-voltage side outlet of the flexible power transformer connected to each new energy station. The new energy machine terminal overvoltage ΔU, when any new energy station is connected to the flexible power transformer high-voltage side outlet single-phase grounding fault The overvoltage ΔU at the terminal of the new energy machine is greater than the withstand voltage threshold ΔU _o of the flexible power transformer, and the flexible power transformer is removed for the new energy station;

9. According to the screening results, determine the configuration scheme of the flexible power transformer for the final power system.

In summary, for the low voltage and overvoltage problems in the power system, the embodiment of the present invention provides an application scenario and demand analysis to configure a suitable flexible power transformer deployment scheme, which can be applied to flexible islands, microgrids, Scenarios such as large-scale new energy external transmission systems can quantify and reflect the grid-related characteristics of flexible power transformers such as switch tube withstand voltage level, over-current capacity, and overload capacity, and improve the operation and regulation capabilities of the grid.

Embodiments of the present invention also provide a device for configuring a flexible power transformer, as described in the following embodiments. Since the problem-solving principle of the device is similar to the configuration method of the flexible power transformer, the implementation of the device can refer to the implementation of the configuration method of the flexible power transformer, and the repetition will not be repeated.

Fig. 5 is a schematic diagram of a configuration device of a flexible power transformer in an embodiment of the present invention. As shown in Fig. 5, the device includes:

The data collection module 501 is used to collect power system data; the power system data includes the short-circuit capacity of the power system and the installed capacity of multiple new energy stations in the power system;

The configuration preparation module 502 is used to calculate the new energy of each new energy station in the power system after determining that the power system is suitable for configuring flexible power transformers according to the short-circuit capacity of the power system and the installed capacity of multiple new energy stations in the power system Multi-site short-circuit ratio;

The flexible power transformer configuration determination module 503 is used to connect the flexible power transformers sequentially according to the order of the capacity of the flexible power transformers from small to large for each new energy site whose short-circuit ratio of multiple new energy sites is not greater than the first preset threshold , recalculate the new energy multi-station short-circuit ratio of the new energy station every time the flexible power transformer is connected, and when the recalculated new energy multi-station short-circuit ratio of the new energy station is greater than the first preset threshold, determine the new The configuration parameters of the flexible power transformer connected to the energy station;

The flexible power transformer configuration screening module 504 is used to use the overcurrent threshold and withstand voltage threshold of the flexible power transformer to screen the configuration parameters of the flexible power transformer connected to each new energy station, and obtain the configuration parameters of the flexible power transformer in the power system .

In one embodiment, the configuration preparation module 502 is specifically used to:

According to the short-circuit capacity of the power system and the installed capacity of multiple new energy stations in the power system, calculate the short-circuit ratio of the power system;

When the short-circuit ratio of the power system is less than or equal to the second preset threshold, it is determined that the power system is suitable for configuring a flexible power transformer.

In one embodiment, the configuration preparation module 502 is specifically used to calculate the new energy multi-station short-circuit ratio of the new energy station according to the following formula:

Among them, MRSCR _i is the new energy multi-station short-circuit ratio of the i-th new energy station, S _aci is the system short-circuit capacity at the i-th new energy station; P _i is the input power of the i-th new energy station Active power, P _j is the active power of the j-th new energy station input to the grid, Z _eqij is the mutual impedance between the i-th new energy station and the j-th new energy station, Z _eqii is the i-th new energy station The self-impedance of the energy station, n is the number of new energy stations, and j is an integer.

In one embodiment, the flexible power transformer configuration screening module 504 is specifically used for:

Calculate the single-phase ground fault short-circuit current of the high-voltage side outlet of the flexible power transformer connected to each new energy station. When the single-phase ground fault short-circuit current of the high-voltage side outlet of the flexible power transformer connected to any new energy station is greater than the The overcurrent threshold of the transformer removes the flexible power transformer for the new energy station;

Calculate the overvoltage of the new energy machine terminal with a single-phase ground fault at the outlet of the high-voltage side of the flexible power transformer connected to each new energy station. If the terminal overvoltage is greater than the withstand voltage threshold of the flexible power transformer, the flexible power transformer is removed for the new energy site.

In one embodiment, the flexible power transformer configuration screening module 504 is specifically used to calculate the single-phase ground fault short-circuit current of the high-voltage side outlet of the flexible power transformer connected to each new energy station according to the following formula:

为型号为T_i的柔性电力变压器阻抗，/>

为与型号T_i的柔性电力变压器低压侧相连的线路L_i的阻抗，U_i为第i个新能源场机端电压。Among them, I is the single-phase ground fault short-circuit current of the high-voltage side outlet of the flexible power transformer connected to the new energy station,

is the impedance of the flexible power transformer whose type is T _i , />

is the impedance of the line L _i connected to the low-voltage side of the flexible power transformer of type T _i , and U _i is the terminal voltage of the i-th new energy field.

In one embodiment, the flexible power transformer configuration screening module 504 is specifically used to calculate the overvoltage of the new energy machine terminal of the flexible power transformer connected to the high-voltage side of the high-voltage side outlet of each new energy station according to the following formula:

Among them, ΔU is the single-phase ground fault overvoltage of the new energy machine terminal of the high-voltage side outlet of the flexible power transformer configured in the new energy station, E is the equivalent potential of the AC system, U _N is the nominal voltage, and MRSCR _i is the ith new energy New energy multi-station short-circuit ratio of the station.

In one embodiment, the overcurrent threshold of the flexible power transformer is obtained according to the following formula:

I _o ＝k ₁ ×I _N

Among them, I _o is the over-current threshold of the flexible power transformer, k ₁ is the over-current coefficient, and I _N is the rated current of the flexible power transformer.

In one embodiment, the withstand voltage threshold of the flexible power transformer is obtained according to the following formula:

ΔU _o =(k ₂ -1)×U _N

Among them, ΔU _o is the withstand voltage threshold of the flexible power transformer, k ₂ is the withstand voltage coefficient, and U _N is the rated voltage of the flexible power transformer.

In one embodiment, the configuration parameters of the flexible power transformer in the device include the access position of any of the following flexible power transformers: voltage level 220/35kV, voltage level 110/35kV, voltage level 110/10kV, voltage level 66 /10kV.

The embodiment of the present invention also provides a computer device, including a memory, a processor, and a computer program stored on the memory and operable on the processor, and the processor implements the configuration method of the above-mentioned flexible power transformer when executing the computer program .

The embodiment of the present invention also provides a computer-readable storage medium, the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the above-mentioned method for configuring the flexible power transformer is realized.

The embodiment of the present invention also provides a computer program product, the computer program product includes a computer program, and when the computer program is executed by a processor, the above-mentioned method for configuring the flexible power transformer is realized.

In the embodiment of the present invention, the power system data is first collected, and the short-circuit capacity of the power system in the power system data and the installed capacity of multiple new energy stations in the power system are used to judge whether the power system is suitable for configuring flexible power transformers; when it is determined that the power system is suitable for Configure flexible power transformers to calculate the short-circuit ratio of each new energy multi-site station; when the new energy multi-site short-circuit ratio meets the conditions, that is, when it is less than or equal to the first preset threshold, connect the flexible power transformer to the new energy station; When selecting the flexible power transformer to be connected to the new energy station, connect it in order according to the capacity of the flexible power transformer from small to large, and recalculate the new energy multi-site short circuit of the new energy station after each connection of the flexible power transformer ratio, when the recalculated new energy multi-station short-circuit ratio of the new energy station is greater than the first preset threshold, determine the configuration parameters of the new energy station connected to the flexible power transformer; finally use the overcurrent threshold and the withstand voltage of the flexible power transformer The voltage threshold value is used to screen the configuration parameters of the flexible power transformers connected to each new energy station to obtain the configuration parameters of the flexible power transformers of the power system, thereby obtaining the configuration scheme of the flexible power transformers of the power system. The embodiment of the present invention realizes the determination of the configuration parameters of the connected flexible power transformer through the short circuit ratio of new energy multi-site stations, and screens the configuration parameters through the overcurrent threshold and withstand voltage threshold of the flexible power transformer, which can be used in the planning and design stage for new Deploying suitable flexible power transformers in energy stations has improved the ability to send new energy and improve the ability to regulate grid operation.

Those skilled in the art should understand that the embodiments of the present invention may be provided as methods, systems, or computer program products. Accordingly, the present invention can take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention may take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) having computer-usable program code embodied therein.

The present invention is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It should be understood that each procedure and/or block in the flowchart and/or block diagram, and a combination of procedures and/or blocks in the flowchart and/or block diagram can be realized by computer program instructions. These computer program instructions may be provided to a general purpose computer, special purpose computer, embedded processor, or processor of other programmable data processing equipment to produce a machine such that the instructions executed by the processor of the computer or other programmable data processing equipment produce a An apparatus for realizing the functions specified in one or more procedures of the flowchart and/or one or more blocks of the block diagram.

These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing apparatus to operate in a specific manner, such that the instructions stored in the computer-readable memory produce an article of manufacture comprising instruction means, the instructions The device realizes the function specified in one or more procedures of the flowchart and/or one or more blocks of the block diagram.

These computer program instructions can also be loaded onto a computer or other programmable data processing device, causing a series of operational steps to be performed on the computer or other programmable device to produce a computer-implemented process, thereby The instructions provide steps for implementing the functions specified in the flow chart or blocks of the flowchart and/or the block or blocks of the block diagrams.

The specific embodiments described above have further described the purpose, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above descriptions are only specific embodiments of the present invention and are not intended to limit the scope of the present invention. Protection scope, within the spirit and principles of the present invention, any modification, equivalent replacement, improvement, etc., shall be included in the protection scope of the present invention.

Claims (21)

1. A method of configuring a flexible power transformer, comprising:

collecting power system data; the power system data comprise short circuit capacity of the power system and installed capacity of a plurality of new energy stations in the power system;

according to the short-circuit capacity of the power system and the installed capacity of a plurality of new energy stations in the power system, after the power system is determined to be suitable for configuring a flexible power transformer, calculating the short-circuit ratio of the new energy stations of each new energy station in the power system;

for each new energy station with the new energy multi-station short-circuit ratio not greater than a first preset threshold value: sequentially accessing the flexible power transformers according to the sequence from small to large of the capacity of the flexible power transformers, recalculating the short-circuit ratio of the new energy multi-station of the new energy station after accessing the flexible power transformers each time, and determining the configuration parameters of the new energy station accessed to the flexible power transformers when the recalculated short-circuit ratio of the new energy multi-station of the new energy station is larger than a first preset threshold value;

and screening the configuration parameters of the flexible power transformer accessed to each new energy station by utilizing the overcurrent threshold and the withstand voltage threshold of the flexible power transformer to obtain the configuration parameters of the flexible power transformer of the power system.

2. The method of claim 1, wherein determining that the power system is suitable for configuring the flexible power transformer based on a short circuit capacity of the power system, an installed capacity of a plurality of new energy sites in the power system, comprises:

calculating the short circuit ratio of the power system according to the short circuit capacity of the power system and the installed capacities of a plurality of new energy stations in the power system;

and when the short circuit ratio of the power system is smaller than or equal to a second preset threshold value, determining that the power system is suitable for configuring the flexible power transformer.

3. The method of claim 1, wherein the new energy multi-station short ratio of the new energy station is calculated according to the following formula:

wherein MRSCR _i A new energy multi-station short-circuit ratio for the ith new energy station, S _aci Short-circuit capacity for the system at the ith new energy station; p (P) _i Inputting active power of a power grid for an ith new energy station, and P _j Inputting active power of a power grid for a jth new energy station, Z _eqij Z is the transimpedance between the ith new energy station and the jth new energy station _eqii The self impedance of the ith new energy station is represented by n, the number of the new energy stations is represented by n, and j is an integer.

4. The method of claim 1, wherein the screening the configuration parameters of the flexible power transformer of the power system for each new energy station access by using the overcurrent threshold and the withstand voltage threshold of the flexible power transformer comprises:

Calculating the single-phase ground fault short-circuit current of the high-voltage side outlet of the flexible power transformer connected with each new energy station, and removing the flexible power transformer for the new energy station when the single-phase ground fault short-circuit current of the high-voltage side outlet of the flexible power transformer connected with any new energy station is larger than the overcurrent threshold of the flexible power transformer;

and calculating the overvoltage of the single-phase ground fault new energy machine end of the high-voltage side outlet of the flexible power transformer connected with each new energy station, and removing the flexible power transformer for the new energy station when the overvoltage of the single-phase ground fault new energy machine end of the high-voltage side outlet of the flexible power transformer connected with any new energy station is larger than the withstand voltage threshold of the flexible power transformer.

5. The method of claim 4, wherein the high side outlet single phase ground fault short circuit current of each flexible power transformer accessed by a new energy station is calculated as:

wherein I is the single-phase ground fault short-circuit current of the high-voltage side outlet of the flexible power transformer accessed by the new energy station,

is of the type T _i Flexible power transformer impedance of>

Is of the type T _i Line impedance, U, of the flexible power transformer low voltage side connection _i The voltage of the field machine end of the ith new energy source is obtained.

6. The method of claim 4, wherein the high-side outlet single-phase ground fault new energy source machine-side overvoltage of the flexible power transformer to which each new energy source station is connected is calculated according to the following formula:

wherein DeltaU is the overvoltage of the single-phase ground fault new energy machine end at the high-voltage side outlet of the flexible power transformer configured by the new energy station, E is the equivalent potential of an alternating current system, U _N For nominal voltage, MRSCR _i And the new energy multi-station short-circuit ratio is the ith new energy station.

7. The method of claim 4, wherein the overcurrent threshold of the flexible power transformer is obtained as follows:

I _o ＝k ₁ ×I _N

wherein I is _o Is the overcurrent threshold, k of the flexible power transformer ₁ For overcurrent coefficient, I _N Is the rated current of the flexible power transformer.

8. The method of claim 4, wherein the withstand voltage threshold of the flexible power transformer is obtained as follows:

ΔU _o ＝(k ₂ -1)×U _N

wherein DeltaU _o Is the withstand voltage threshold value, k of the flexible power transformer ₂ Is a pressure-resistant coefficient, U _N Is the rated voltage of the flexible power transformer.

9. The method of claim 1, wherein the configuration parameters of the flexible power transformer include an access location of any one of the following flexible power transformers: 220/35kV voltage class, 110/10kV voltage class and 66/10kV voltage class.

10. A configuration device of a flexible power transformer, comprising:

the data collection module is used for collecting power system data; the power system data comprise short circuit capacity of the power system and installed capacity of a plurality of new energy stations in the power system;

the configuration preparation module is used for calculating the short-circuit ratio of the new energy multi-station of each new energy station in the power system after determining that the power system is suitable for configuring the flexible power transformer according to the short-circuit capacity of the power system and the installed capacities of the plurality of new energy stations in the power system;

the flexible power transformer configuration determining module is used for each new energy station with the short circuit ratio of the new energy stations not larger than a first preset threshold value: sequentially accessing the flexible power transformers according to the sequence from small to large of the capacity of the flexible power transformers, recalculating the short-circuit ratio of the new energy multi-station of the new energy station after accessing the flexible power transformers each time, and determining the configuration parameters of the new energy station accessed to the flexible power transformers when the recalculated short-circuit ratio of the new energy multi-station of the new energy station is larger than a first preset threshold value;

and the flexible power transformer configuration screening module is used for screening the configuration parameters of the flexible power transformer accessed to each new energy station by utilizing the overcurrent threshold and the withstand voltage threshold of the flexible power transformer to obtain the configuration parameters of the flexible power transformer of the power system.

11. The apparatus of claim 10, wherein the configuration preparation module is specifically configured to:

calculating the short circuit ratio of the power system according to the short circuit capacity of the power system and the installed capacities of a plurality of new energy stations in the power system;

and when the short circuit ratio of the power system is smaller than or equal to a second preset threshold value, determining that the power system is suitable for configuring the flexible power transformer.

12. The apparatus of claim 10, wherein the configuration preparation module is specifically configured to calculate a new energy multi-station short-circuit ratio for the new energy station according to the following formula:

wherein MRSCR _i A new energy multi-station short-circuit ratio for the ith new energy station, S _aci Short-circuit capacity for the system at the ith new energy station; p (P) _i Inputting active power of a power grid for an ith new energy station, and P _j Inputting active power of a power grid for a jth new energy station, Z _eqij Z is the transimpedance between the ith new energy station and the jth new energy station _eqii Is the self-impedance of the ith new energy station.

13. The apparatus of claim 10, wherein the flexible power transformer configuration screening module is specifically configured to:

calculating the single-phase ground fault short-circuit current of the high-voltage side outlet of the flexible power transformer connected with each new energy station, and removing the flexible power transformer for the new energy station when the single-phase ground fault short-circuit current of the high-voltage side outlet of the flexible power transformer connected with any new energy station is larger than the overcurrent threshold of the flexible power transformer;

And calculating the overvoltage of the single-phase ground fault new energy machine end of the high-voltage side outlet of the flexible power transformer connected with each new energy station, and removing the flexible power transformer for the new energy station when the overvoltage of the single-phase ground fault new energy machine end of the high-voltage side outlet of the flexible power transformer connected with any new energy station is larger than the withstand voltage threshold of the flexible power transformer.

14. The apparatus of claim 13, wherein the flexible power transformer configuration screening module is specifically configured to calculate a high side outlet single phase ground fault short circuit current of the flexible power transformer for each new energy station access according to the following formula:

wherein I is the single-phase ground fault short-circuit current of the high-voltage side outlet of the flexible power transformer accessed by the new energy station,

is of the type T _i Flexible power transformer impedance of>

Is of the type T _i Line impedance, U, of the flexible power transformer low voltage side connection _i The voltage of the field machine end of the ith new energy source is obtained.

15. The apparatus of claim 13, wherein the flexible power transformer configuration screening module is specifically configured to calculate a single-phase ground fault new energy source terminal overvoltage at a high-voltage side outlet of the flexible power transformer to which each new energy station is connected according to the following formula:

Wherein DeltaU is the overvoltage of the single-phase ground fault new energy machine end at the high-voltage side outlet of the flexible power transformer configured by the new energy station, E is the equivalent potential of an alternating current system, U _N For nominal voltage, MRSCR _i And the new energy multi-station short-circuit ratio is the ith new energy station.

16. The apparatus of claim 13, wherein the overcurrent threshold of the flexible power transformer is obtained as follows:

I _o ＝k ₁ ×I _N

wherein I is _o Is the overcurrent threshold, k of the flexible power transformer ₁ For overcurrent coefficient, I _N Is the rated current of the flexible power transformer.

17. The apparatus of claim 13, wherein the withstand voltage threshold of the flexible power transformer is obtained as follows:

ΔU _o ＝(k ₂ -1)×U _N

wherein DeltaU _o Is the withstand voltage threshold value, k of the flexible power transformer ₂ Is a pressure-resistant coefficient, U _N Is the rated voltage of the flexible power transformer.

18. The apparatus of claim 10, wherein the configuration parameters of the flexible power transformer include an access location of any one of the following flexible power transformers: 220/35kV voltage class, 110/10kV voltage class and 66/10kV voltage class.

19. A computer device comprising a memory, a processor and a computer program stored on the memory and executable on the processor, characterized in that the processor implements the method of any of claims 1 to 9 when executing the computer program.

20. A computer readable storage medium, characterized in that the computer readable storage medium stores a computer program which, when executed by a processor, implements the method of any of claims 1 to 9.

21. A computer program product, characterized in that the computer program product comprises a computer program which, when executed by a processor, implements the method of any of claims 1 to 9.

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