Real-time simulator and feeder terminal characteristic test method

Abstract

The embodiments of the present invention relate to the field of electric power, and disclose a real-time simulator and a method for testing the characteristics of feeder terminals. In the present invention, the real-time simulator includes: a medium-voltage distribution network model and a low-voltage distribution substation model; the medium-voltage distribution network model is used to connect to the feeder terminal under test; the low-voltage distribution substation model includes a substation transformer model, and a plurality of power electronic equipment models connected to the substation transformer model, and the substation transformer model is connected to the medium-voltage network node of the medium-voltage distribution network model and is used to connect to the substation intelligent terminal. The real-time simulator and the method for testing the characteristics of the feeder terminal provided by the present invention can simulate the scenario where the medium-voltage network of the distribution network presents bidirectional power flow characteristics, thereby improving the accuracy of the characteristic test results of the feeder terminal.

Description

Technical Field

[0001] The embodiments of the present invention relate to the field of electric power, and in particular to a real-time simulator and a method for testing characteristics of a feeder terminal. Background Art

[0002] In the related art, it is proposed to conduct system-level functional testing on various local power distribution terminals by constructing a virtual-real combined local FA logic system-level testing environment.

[0003] The inventors have discovered that there are at least the following problems in the prior art: in the related art, the accuracy of the test results of the feeder terminal characteristics is low, and it is difficult to meet the test requirements for the feeder terminal. Summary of the Invention

[0004] The purpose of the embodiments of the present invention is to provide a real-time simulator and a characteristic testing method for a feeder terminal, which can simulate a scenario in which a medium-voltage distribution network presents bidirectional power flow characteristics, thereby improving the accuracy of the characteristic test results of the feeder terminal.

[0005] In order to solve the above technical problems, an embodiment of the present invention provides a real-time simulation machine, including: a distribution medium-voltage network model and a distribution low-voltage substation model; the distribution medium-voltage network model is used to be connected to the feeder terminal under test; the distribution low-voltage substation model includes a substation transformer model, and multiple power electronic equipment models connected to the substation transformer model, the substation transformer model is connected to the medium-voltage network node of the distribution medium-voltage network model, and is used to be connected to the substation intelligent terminal.

[0006] An embodiment of the present invention also provides a characteristic testing method for a feeder terminal, comprising: constructing a distribution medium-voltage network model and a distribution low-voltage substation model, wherein the distribution medium-voltage network model is used to connect to the feeder terminal under test, and the distribution low-voltage substation model includes a substation transformer model, and a plurality of power electronic equipment models connected to the substation transformer model, the substation transformer model is connected to the medium-voltage network node of the distribution medium-voltage network model, and is used to connect to the substation intelligent terminal; using the substation intelligent terminal to adjust the distribution low-voltage substation model to enter the first steady-state operating condition before the test; recording the actual response result of the feeder terminal under test under the first steady-state operating condition; obtaining the ideal response result under the first steady-state operating condition; comparing the actual response result with the ideal response result to determine the qualification of the feeder terminal under test.

[0007] Compared with the prior art, the embodiments of the present invention construct a distribution network medium-voltage network model and a distribution low-voltage substation model containing a large number of power electronic equipment corresponding to the feeder terminal under test through a real-time simulation machine, realize the mirror simulation modeling of the test environment and the information closed-loop interaction test between the real feeder terminal under test and the mirror simulation environment. Compared with the traditional method of only considering the influence of the unidirectional flow characteristics of the distribution network medium-voltage network on the feeder terminal characteristic test results, it more deeply considers the influence of the bidirectional flow characteristics of the medium-voltage network caused by the power electronic equipment introduced by the large-scale new energy in the low-voltage substation of the distribution network on the feeder terminal characteristic test results, and is more in line with the actual operation scenario of the bidirectional flow of the current active distribution network. By simulating the scenario of the medium-voltage network of the distribution network presenting bidirectional flow characteristics, the accuracy of the characteristic test results of the feeder terminal is improved.

[0008] In addition, the distribution medium-voltage network model includes multiple medium-voltage switch models and multiple feeder terminal virtual models. The multiple medium-voltage switch models include a first medium-voltage switch model and multiple second medium-voltage switch models. The first medium-voltage switch model is used to be connected to the feeder terminal under test, and the multiple second medium-voltage switch models are connected to the multiple feeder terminal virtual models in a one-to-one correspondence; the substation transformer model and any one of the multiple second medium-voltage switch models are connected to the medium-voltage network node.

[0009] In addition, it also includes: a first power amplifier and a first switching value conversion device, both of which are used to be connected to the feeder terminal under test; the first medium-voltage switch model is connected to the first power amplifier to output voltage and current to the feeder terminal under test via the first power amplifier; the first medium-voltage switch model is connected to the first switching value conversion device to exchange information with the feeder terminal under test via the first switching value conversion device.

[0010] In addition, it also includes: a second power amplifier for connecting to the substation intelligent terminal; the substation transformer model is connected to the second power amplifier to output voltage and current to the substation intelligent terminal via the second power amplifier.

[0011] In addition, the distribution low-voltage substation model also includes: a main branch switch model connected to the substation transformer model, and multiple branch switch models respectively connected to the main branch switch model, and the multiple power electronic equipment models are connected to the multiple branch switch models in a one-to-one correspondence; the main branch switch model, the multiple branch switch models and the multiple power electronic equipment models all interact with the substation intelligent terminal through a communication protocol.

[0012] In addition, the power electronic device model includes: a power electronic device power circuit model connected to the substation transformer model, and a valid dynamic link library model of a controller source code package connected to the power electronic device power circuit model.

[0013] In addition, there are multiple distribution low-voltage substation models, and the substation transformer model in each distribution low-voltage substation model is respectively connected to a different medium-voltage network node of the distribution medium-voltage network model.

[0014] In addition, the power electronic device model includes: a power electronic device power loop model connected to the substation transformer model, and an effective dynamic link library model of the controller source code package connected to the power electronic device power loop model; obtaining the effective dynamic link library model, including: providing a power electronic device power loop model, a substation transformer model and a medium voltage network node equivalent voltage source model connected in series, and outputting the voltage and current at the first connection point between the power electronic device power loop model and the substation transformer model to the power electronic device real controller through the analog output board in the real-time simulator, and obtaining the first response result of the first connection point when the digital signal in the power electronic device power loop model interacts with the power electronic device real controller through the digital input / output board in the real-time simulator; constructing a dynamic link library model of the power electronic device controller source code package. A dynamic link library model is provided; a power electronic device power circuit model, a substation transformer model, and a medium voltage network node equivalent voltage source model are provided in series; the voltage and current at the second connection point between the power electronic device power circuit model and the substation transformer model are directly output to the dynamic link library model of the power electronic device controller source code package, and the digital signal in the power electronic device power circuit model directly interacts with the dynamic link library model of the power electronic device controller source code package, thereby obtaining a second response result of the second connection point; and determining whether the difference between the first response result and the second response result is less than a preset error value. If so, determining that the dynamic link library model of the power electronic device controller source code package is a valid dynamic link library model of the controller source code package; if not, reconstructing the dynamic link library model of the power electronic device controller source code package. Such a setting can avoid the influence of the substation transformer and the distribution medium voltage network node on the electromagnetic transient modeling of the wind power converter or other power electronic devices on the low voltage side of the substation transformer, and further improve the accuracy of the characteristic test results of the feeder terminal.

[0015] In addition, before using the substation intelligent terminal to adjust the distribution low-voltage substation model to enter the first steady-state operating condition before the test, it also includes: setting a first grounding fault on the low-voltage side or the medium-voltage side of the substation transformer model, and the ideal response result is the ideal response result under the first grounding fault; wherein, the first grounding fault includes: any one of a single-phase grounding fault, a two-phase grounding fault, a phase-to-phase short-circuit fault and a three-phase grounding fault, or any combination thereof. Such a setting can avoid the influence of single-phase grounding faults, two-phase grounding faults, phase-to-phase short-circuit faults or three-phase grounding faults on the low-voltage side and the medium-voltage side of the substation transformer on the verification results, and further improve the accuracy of the characteristic test results of the feeder terminal. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] One or more embodiments are exemplarily illustrated by pictures in the corresponding drawings. These exemplifications do not constitute limitations on the embodiments. Elements with the same reference numerals in the drawings are represented as similar elements. Unless otherwise stated, the figures in the drawings do not constitute proportional limitations.

[0017] Figure 1 This is the structural intention of the real-time simulation machine provided by the first embodiment of the present invention;

[0018] Figure 2 is a flow chart of a characteristic testing method of a feeder terminal provided by a second embodiment of the present invention;

[0019] Figure 3 is a flow chart of obtaining a valid dynamic link library model in the second embodiment of the present invention;

[0020] Figure 4 This is the structural intention of obtaining the first response result of the first connection point in the second embodiment of the present invention;

[0021] Figure 5 This is the structural intention of obtaining the second response result of the second connection point in the second embodiment of the present invention. DETAILED DESCRIPTION

[0022] To make the purpose, technical solutions, and advantages of the embodiments of the present invention more clear, each embodiment of the present invention will be described in detail below with reference to the accompanying drawings. However, those skilled in the art will appreciate that in each embodiment of the present invention, many technical details are provided to help readers better understand the present application. However, even without these technical details and various changes and modifications based on the following embodiments, the technical solutions claimed in the present application can still be implemented.

[0023] When renewable energy, primarily power electronics, is integrated into the distribution network on a large scale and at a high rate, a large number of power electronic devices located in the low-voltage substations of the distribution network will inject reverse current through the low-voltage side of the substation transformer to the medium-voltage side of the substation transformer, i.e., the distribution medium-voltage network nodes. This causes the distribution medium-voltage network to transform from a traditional unidirectional current flow characteristic to a bidirectional current flow characteristic. Related technologies propose constructing a virtual-real on-site FA logic system-level test environment to conduct system-level functional testing of various on-site distribution terminals.

[0024] The inventors found that since the scenario of a large number of power electronic equipment injecting reverse current through the low-voltage side of the substation transformer to the medium-voltage side of the substation transformer, that is, the distribution medium-voltage network node, was not considered, the impact of the substation transformer and the distribution medium-voltage network node on the electromagnetic transient modeling of wind power converters or other power electronic equipment on the low-voltage side of the substation transformer was not considered, and the impact of single-phase grounding faults, two-phase grounding faults, phase-to-phase short-circuit faults or three-phase grounding faults on the low-voltage and medium-voltage sides of the substation transformer on the verification results was not specifically considered, the accuracy of the feeder terminal characteristic test results is low.

[0025] The first embodiment of the present invention relates to a real-time simulation machine, such as Figure 1 As shown, it includes: a distribution medium-voltage network model and a distribution low-voltage substation model, wherein the distribution medium-voltage network model is used to connect to the feeder terminal under test, and the distribution low-voltage substation model includes a substation transformer model (substation transformer model 1_1 or substation transformer model 2_1), and multiple power electronic equipment models connected to the substation transformer model (power electronic equipment model 1_1, power electronic equipment model 1_2, power electronic equipment model 1_3, or power electronic equipment model 2_1, power electronic equipment model 2_2, power electronic equipment model 2_3), the substation transformer model is connected to the medium-voltage network node (for example, node 1 or node 2) of the distribution medium-voltage network model, and is used to connect to the substation intelligent terminal (TTU1 or TTU2).

[0026] By constructing a medium-voltage network model and a low-voltage substation model of the active distribution network containing power electronic equipment corresponding to the medium-voltage switch where the feeder terminal under test is located, mirror simulation modeling of the medium-voltage and low-voltage test environments and information closed-loop interaction testing between the actual feeder terminal under test and the mirror simulation environment are realized, thereby improving the accuracy of the test results of the feeder terminal under test.

[0027] Specifically, the distribution medium-voltage network model may include multiple medium-voltage switch models S1, S2, S3...S12, and multiple feeder terminal virtual models FTUj (j is a natural number, 1≤j≤12 and j≠7), the multiple medium-voltage switch models include a first medium-voltage switch model S7 and multiple second medium-voltage switch models Sj (j is a natural number, 1≤j≤12 and j≠7), the first medium-voltage switch model is used to be connected to the feeder terminal FTU under test, the multiple second medium-voltage switch models Sj are connected one-to-one to the multiple feeder terminal virtual models FTUj, and the substation transformer model is connected to any one of the multiple second medium-voltage switch models (for example, the second medium-voltage switch model S4 or S9) at the medium-voltage network node (for example, node 1 or node 2).

[0028] In actual applications, the real-time simulation machine may also include: a first power amplifier (i.e., power amplifier 1) and a first switching value conversion device (switching value conversion device 1), both of which are used to be connected to the feeder terminal FTU under test, the first medium-voltage switch model S7 is connected to the first power amplifier to output voltage and current to the feeder terminal FTU under test via the first power amplifier, and the first medium-voltage switch model S7 is connected to the first switching value conversion device to exchange information with the feeder terminal FTU under test via the first switching value conversion device.

[0029] Optionally, the real-time simulation machine may further include: a second power amplifier (power amplifier 1_1) for connecting to the substation intelligent terminal, and the substation transformer model is connected to the second power amplifier to output voltage and current to the substation intelligent terminal via the second power amplifier.

[0030] In actual applications, the distribution low-voltage substation model also includes: a main branch switch model (L1 or L2) connected to the substation transformer model, multiple branch switch models (L1_1, L1_2, L1_3, or L2_1, L2_2, L2_3) respectively connected to the main branch switch model, and multiple power electronic equipment models are connected to the multiple branch switch models in a one-to-one correspondence. The main branch switch model, multiple branch switch models and multiple power electronic equipment models all exchange information with the substation intelligent terminal through a communication protocol.

[0031] The power electronic equipment model may include: a power electronic equipment power loop model connected to the substation transformer model, and a valid dynamic link library model of a controller source code package connected to the power electronic equipment power loop model.

[0032] Optionally, there can be multiple distribution low-voltage substation models, and the substation transformer models in each distribution low-voltage substation model are respectively connected to different medium-voltage network nodes of the distribution medium-voltage network model. In this embodiment, the number of distribution low-voltage substation models is two, namely distribution low-voltage substation model 1 and distribution low-voltage substation model 2, and distribution low-voltage substation model 1 and distribution low-voltage substation model 2 are respectively connected to node 1 and node 2.

[0033] In other words, the active distribution network mirror simulation environment is composed of the distribution medium-voltage network model and the distribution low-voltage substation model i (i is a natural number) in the real-time simulation machine. The medium-voltage side of the substation transformer model i_1 of the low-voltage substation model i is connected to the medium-voltage network node i of the distribution medium-voltage network model.

[0034] Among them, the distribution medium-voltage network model is a typical grid structure model of a typical medium-voltage distribution network such as a radial, ring network or petal type, which is composed of multiple medium-voltage switch models S1, S2, S3...SK...SN (K and N are both natural numbers, and 1≤K≤N). The input side voltage and current of the SK medium-voltage switch model (i.e., the first medium-voltage switch model) are output to the feeder terminal FTU under test through the power amplifier 1. The switch closing / opening information in the SK medium-voltage switch model is exchanged with the feeder terminal FTU under test through the switch quantity conversion device. The remaining medium-voltage switch models Sj all exchange information with the corresponding feeder terminal virtual model FTUj (j is a natural number, 1≤j≤N and j≠K).

[0035] The distribution low-voltage substation model i includes the substation transformer model i_1. The low-voltage side voltage and current of the substation transformer model i_1 are output to the substation intelligent terminal TTUi through the power amplifier i_1. The main branch switch model Li, branch switch model Li_1, power electronic equipment model i_1, branch switch model Li_2, power electronic equipment model i_2, branch switch model Li_3, and non-power electronic equipment model i_3 contained in the distribution low-voltage substation model i are all connected to the substation intelligent terminal TTUi through the communication protocol. Perform switch switching or active / reactive power information exchange, wherein the power electronic device model i_1 and the power electronic device model i_2 are both composed of an actual power electronic device power loop model and an effective dynamic link library model encapsulated by the controller source code. The input end of the main branch switch model Li is connected to the low-voltage side of the substation transformer model i_1, and the output end of the main branch switch model Li is respectively connected to the input end of the branch switch model Li_1, the input end of the branch switch model Li_2, and the input end of the branch switch model Li_3; the output end of the branch switch model Li_1 is connected to the input end of the power electronic device model i_1, the output end of the branch switch model Li_2 is connected to the input end of the power electronic device model i_2, and the output end of the branch switch model Li_3 is connected to the input end of the non-power electronic device model i_3. The non-power electronic device model can be modeled by setting the equivalent parameters of R, L or C according to the equivalent RLC model of the passive device.

[0036] Compared with the prior art, the embodiment of the present invention constructs a distribution network medium-voltage network model and a distribution low-voltage substation model corresponding to the tested feeder terminal, which contain a large number of power electronic equipment. That is, in the traditional distribution medium-voltage network model, a distribution low-voltage substation model containing a large number of power electronic equipment is introduced, thereby realizing the mirror simulation modeling of the test environment and the information closed-loop interaction test between the real tested feeder terminal and the mirror simulation environment. Compared with the traditional method of only considering the influence of the unidirectional flow characteristics of the distribution network medium-voltage network on the feeder terminal characteristic test results, the embodiment of the present invention more deeply considers the influence of the bidirectional flow characteristics of the medium-voltage network caused by the power electronic equipment introduced by the large-scale new energy in the distribution network low-voltage substation on the feeder terminal characteristic test results. It is more in line with the actual operation scenario of the bidirectional flow of the current active distribution network, and the test results are more effective and reliable. By simulating the scenario where the distribution network medium-voltage network presents bidirectional flow characteristics, the accuracy of the characteristic test results of the feeder terminal is improved.

[0037] It is worth noting that all modules involved in this embodiment are logical modules. In actual applications, a logical unit can be a physical unit, a part of a physical unit, or a combination of multiple physical units. In addition, to highlight the innovations of the present invention, this embodiment does not include units that are not closely related to solving the technical problems proposed by the present invention. However, this does not mean that other units do not exist in this embodiment.

[0038] The second embodiment of the present invention provides a method for testing characteristics of a feeder terminal, such as Figure 2 As shown, the following steps are included:

[0039] S11: Construct the distribution medium voltage network model and distribution low voltage substation model.

[0040] Among them, the distribution medium-voltage network model is used to connect to the feeder terminal under test, the distribution low-voltage substation model includes a substation transformer model and multiple power electronic equipment models connected to the substation transformer model. The substation transformer model is connected to the medium-voltage network node of the distribution medium-voltage network model and is used to connect to the substation intelligent terminal.

[0041] Specifically, the power electronic equipment model may include: a power electronic equipment power loop model connected to the substation transformer model, and a valid dynamic link library model of a controller source code package connected to the power electronic equipment power loop model.

[0042] The following is combined with Figure 3 Specifically, obtaining a valid dynamic link library model may include the following steps:

[0043] S21: Obtain a first response result of the first connection point.

[0044] In this step, if Figure 4 As shown, a power electronic device power loop model, a substation transformer model and a medium-voltage network node equivalent voltage source model connected in series are provided. The voltage and current of the first connection point PCC1 between the power electronic device power loop model and the substation transformer model are output to the real controller of the power electronic device through the analog output board in the real-time simulation machine. The digital signal in the power electronic device power loop model interacts with the real controller of the power electronic device through the digital input / output board in the real-time simulation machine, and the first response result of the first connection point PCC1 is obtained.

[0045] In actual application, the power circuit model of power electronic device i_1, the substation transformer model i_1 and the equivalent voltage source model of medium voltage network node i are connected in series in the real-time simulation machine. The actual electrical parameters of the actual substation transformer i_1 are set in the substation transformer model i_1. The equivalent voltage source model of medium voltage network node i is to set the voltage level and equivalent reactance parameters of the actual medium voltage network node i in the voltage source model. The power circuit model of power electronic device i_1 and substation transformer model i_1 are connected in series. The voltage and current of the connection point PCC1 are output to the real controller of the power electronic device i_1 through the analog output board in the real-time simulator, and the digital signals such as the power electronic switch and the grid-connected switch in the power circuit model of the power electronic device i_1 interact with the real controller of the power electronic device i_1 through the digital input / output board in the real-time simulator; for the three typical steady-state operating conditions of light load (10% to 50% rated power), half load (50% rated power), and heavy load (50% to 100% rated power) of the power circuit model of the power electronic device i_1, a single-phase grounding fault, a two-phase grounding fault, a phase-to-phase short circuit fault, or a three-phase grounding fault is set on the low-voltage side or the medium-voltage side of the substation transformer model i_1, and the first response result of the first connection point PCC1 is recorded.

[0046] S22: Construct a dynamic link library model for power electronic equipment controller source code packaging.

[0047] S23: Obtain a second response result of the second connection point.

[0048] In this step, if Figure 5 As shown, a power electronic device power loop model, a substation transformer model and a medium-voltage network node equivalent voltage source model connected in series are provided, and the voltage and current of the second connection point PCC2 between the power electronic device power loop model and the substation transformer model are directly output to the dynamic link library model encapsulated by the power electronic device controller source code, and the digital signal in the power electronic device power loop model directly interacts with the dynamic link library model encapsulated by the power electronic device controller source code, and the second response result of the second connection point PCC2 is obtained.

[0049] In actual application, the power circuit model of power electronic device i_1, the substation transformer model i_1 and the equivalent voltage source model of medium voltage network node i are connected in series in the real-time simulation machine. The actual electrical parameters of the actual substation transformer i_1 are set in the substation transformer model i_1. The equivalent voltage source model of medium voltage network node i is to set the voltage level and equivalent reactance parameters of the actual medium voltage network node i in the voltage source model. The power circuit model of power electronic device i_1 and substation transformer model i_1 are connected in series. The voltage and current of the connection point PCC2 are directly output to the dynamic link library model of the real controller source code encapsulation of the power electronic device i_1, and the digital signals such as the power electronic switches and grid-connected switches in the power loop model of the power electronic device i_1 directly interact with the dynamic link library model of the real controller source code encapsulation of the power electronic device i_1; for the three typical steady-state operating conditions of light load (10% to 50% rated power), half load (50% rated power), and heavy load (50% to 100% rated power) of the power loop model of the power electronic device i_1, a single-phase grounding fault, a two-phase grounding fault, a phase-to-phase short circuit fault or a three-phase grounding fault is set on the low-voltage side or the medium-voltage side of the substation transformer model i_1, and the response results of the second connection point PCC2 are recorded.

[0050] S24: Determine whether the difference between the first response result and the second response result is less than a preset error value. If so, execute step S25; if not, return to step S22.

[0051] In practical applications, the PCC1 response results and PCC2 response results recorded during the test under the same fault conditions of the power circuit model of power electronic device i_1 under three typical steady-state operating conditions: light load (10% to 50% of rated power), half load (50% of rated power), and heavy load (50% to 100% of rated power) can be compared and analyzed. If the maximum deviation between the PCC1 response results and the PCC2 response results for the scenarios of single-phase grounding fault, two-phase grounding fault, phase-to-phase short circuit fault, or three-phase grounding fault on the low-voltage or medium-voltage side of the substation transformer model i_1 under various steady-state operating conditions does not exceed 15%, then the dynamic link library model of the source code package of the real controller of power electronic device i_1 obtained in step S22 is a valid dynamic link library model of the source code package of the real controller of power electronic device i_1. Otherwise, steps S22, S23, and S24 are repeated. The power circuit model of power electronic device i_1 and the valid dynamic link library model of the source code package of the real controller of power electronic device i_1 constitute the power electronic device model i_1.

[0052] S25: Determine whether the dynamic link library model of the power electronic device controller source code package is a valid dynamic link library model of the controller source code package.

[0053] Since the influence of the substation transformer and the distribution medium-voltage network nodes on the electromagnetic transient modeling of the power electronic equipment on the low-voltage side of the substation transformer is fully considered, and by specifically considering the influence of single-phase grounding faults, two-phase grounding faults, phase-to-phase short circuit faults or three-phase grounding faults on the low-voltage and medium-voltage sides of the substation transformer on the verification results, the power electronic equipment mirror modeling method proposed for this distribution network low-voltage substation scenario containing a large number of power electronic equipment is more effective, thereby ensuring that the constructed medium-voltage network model and low-voltage substation model of the active distribution network containing power electronic equipment where the medium-voltage switch is located at the tested feeder terminal are more effective, realizing the mirror simulation modeling of the medium-voltage and low-voltage test environments and the information closed-loop interaction test between the real tested feeder terminal and the mirror simulation environment, thereby improving the accuracy of the test results of the tested feeder terminal.

[0054] S12: Use the substation intelligent terminal to adjust the distribution low-voltage substation model to enter the first steady-state operating condition before testing.

[0055] Optionally, before step S12, the method further includes: setting a first ground fault on the low-voltage side or the medium-voltage side of the substation transformer model, where the ideal response result is the ideal response result under the first ground fault; wherein the first ground fault includes: any one of a single-phase ground fault, a two-phase ground fault, a phase-to-phase short-circuit fault, and a three-phase ground fault, or any combination thereof. This configuration can avoid the impact of single-phase ground faults, two-phase ground faults, phase-to-phase short-circuit faults, or three-phase ground faults on the low-voltage side and the medium-voltage side of the substation transformer on the verification results, further improving the accuracy of the characteristic test results of the feeder terminal.

[0056] S13: Recording the actual response result of the feeder terminal under the first steady-state operating condition.

[0057] S14: Obtain an ideal response result under the first steady-state operating condition.

[0058] S15: Compare the actual response result with the ideal response result to determine the eligibility of the feeder terminal under test.

[0059] Specifically, if the error between the actual response result and the ideal response result is less than a preset value, the feeder terminal under test is determined to be qualified; if the error between the actual response result and the ideal response result is greater than or equal to the preset value, the feeder terminal under test is determined to be unqualified.

[0060] In actual applications, when the actual feeder terminal FTU under test and the substation intelligent terminal TTUi are connected to the distribution medium-voltage network model and the distribution low-voltage substation model i in the real-time simulator through an interface module (the interface module includes a power amplifier, a switching conversion device, a communication interface, and a communication protocol, etc.), the substation intelligent terminal TTUi adjusts the distribution low-voltage substation model i to enter a certain steady-state operating condition that must be achieved before testing. By setting a single-phase grounding fault, a two-phase grounding fault, a phase-to-phase short-circuit fault, or a three-phase grounding fault on the low-voltage side or the medium-voltage side of the substation transformer model i_1, the response results of the feeder terminal FTU under test are recorded and compared with the theoretical design results to determine whether the response function of the feeder terminal FTU under test is qualified under the test condition.

[0061] The steps of the various methods above are divided only for the purpose of clear description. During implementation, they can be combined into one step or some steps can be split and decomposed into multiple steps. As long as they include the same logical relationship, they are all within the scope of protection of this patent. Adding insignificant modifications or introducing insignificant designs to the algorithm or process without changing the core design of the algorithm and process are all within the scope of protection of this patent.

[0062] It is not difficult to find that this embodiment is a method example corresponding to the first embodiment, and this embodiment can be implemented in conjunction with the first embodiment. The relevant technical details mentioned in the first embodiment are still valid in this embodiment, and to reduce repetition, they are not repeated here. Accordingly, the relevant technical details mentioned in this embodiment can also be applied to the first embodiment.

[0063] Those skilled in the art will appreciate that the above-mentioned embodiments are specific examples for implementing the present invention, and that in actual applications, various changes may be made thereto in form and detail without departing from the spirit and scope of the present invention.

Claims

1. A real-time simulation machine, characterized in that: include: Distribution medium voltage network model, distribution low voltage substation model; The power distribution medium voltage network model is used to connect to the feeder terminal under test; The power distribution low-voltage substation model includes a substation transformer model and a plurality of power electronic equipment models connected to the substation transformer model. The substation transformer model is connected to the medium-voltage network node of the power distribution medium-voltage network model and is used to connect to the substation intelligent terminal; The power electronic device model includes: a power electronic device power circuit model connected to the substation transformer model, and a valid dynamic link library model of a controller source code package connected to the power electronic device power circuit model; Obtaining the valid dynamic link library model includes: A power circuit model of a power electronic device, a substation transformer model, and a medium-voltage network node equivalent voltage source model connected in series are provided, the voltage and current at a first connection point between the power electronic device power circuit model and the substation transformer model are output to a real controller of the power electronic device via an analog output board in a real-time simulator, and a first response result of the first connection point is obtained when a digital signal in the power circuit model of the power electronic device interacts with the real controller of the power electronic device via a digital input / output board in the real-time simulator; Construct a dynamic link library model for power electronic equipment controller source code packaging; Providing a power electronic device power loop model, a substation transformer model, and a medium-voltage network node equivalent voltage source model connected in series, directly outputting the voltage and current at a second connection point between the power electronic device power loop model and the substation transformer model to a dynamic link library model encapsulated by the power electronic device controller source code, and obtaining a second response result of the second connection point when a digital signal in the power electronic device power loop model directly interacts with the dynamic link library model encapsulated by the power electronic device controller source code; Determine whether the difference between the first response result and the second response result is less than a preset error value; if so, determine that the dynamic link library model of the power electronic device controller source code package is a valid dynamic link library model of the controller source code package; if not, reconstruct the dynamic link library model of the power electronic device controller source code package.

2. The real-time simulation machine according to claim 1, characterized in that: The power distribution medium-voltage network model includes a plurality of medium-voltage switch models and a plurality of feeder terminal virtual models, wherein the plurality of medium-voltage switch models include a first medium-voltage switch model and a plurality of second medium-voltage switch models, wherein the first medium-voltage switch model is used to be connected to the feeder terminal under test, and the plurality of second medium-voltage switch models are connected to the plurality of feeder terminal virtual models in a one-to-one correspondence; The substation transformer model and any one of the plurality of second medium-voltage switch models are connected to the medium-voltage network node.

3. The real-time simulation machine according to claim 2, characterized in that: Also includes: A first power amplifier and a first switching value conversion device, both of which are connected to the feeder terminal under test; The first medium voltage switch model is connected to the first power amplifier to output voltage and current to the feeder terminal under test via the first power amplifier; The first medium-voltage switch model is connected to the first switch value conversion device to perform information exchange with the feeder terminal under test via the first switch value conversion device.

4. The real-time simulation machine according to claim 1, characterized in that: Also includes: A second power amplifier connected to an intelligent terminal in the substation area; The substation transformer model is connected to the second power amplifier to output voltage and current to the substation intelligent terminal via the second power amplifier.

5. The real-time simulation machine according to claim 1, characterized in that: The power distribution low-voltage substation model further includes: a main branch switch model connected to the substation transformer model, and multiple branch switch models respectively connected to the main branch switch model, and the multiple power electronic equipment models are connected to the multiple branch switch models in a one-to-one correspondence; The main branch switch model, the multiple branch switch models and the multiple power electronic equipment models all exchange information with the substation intelligent terminal through a communication protocol.

6. The real-time simulation machine according to claim 1, characterized in that: There are multiple distribution low-voltage substation models, and each substation transformer model in the distribution low-voltage substation model is connected to a different medium-voltage network node of the distribution medium-voltage network model.

7. A method for testing characteristics of a feeder terminal, characterized in that: include: Constructing a power distribution medium-voltage network model and a power distribution low-voltage substation model, wherein the power distribution medium-voltage network model is used to connect to the feeder terminal under test, and the power distribution low-voltage substation model includes a substation transformer model and multiple power electronic equipment models connected to the substation transformer model, and the substation transformer model is connected to the medium-voltage network node of the power distribution medium-voltage network model and is used to connect to the substation intelligent terminal; Using the substation intelligent terminal to adjust the distribution low-voltage substation model to enter a first steady-state operating condition before testing; Recording an actual response result of the feeder terminal under the first steady-state operating condition; Obtaining an ideal response result under the first steady-state operating condition; Comparing the actual response result with the ideal response result to determine the eligibility of the feeder terminal under test; The power electronic device model includes: a power electronic device power circuit model connected to the substation transformer model, and a valid dynamic link library model of a controller source code package connected to the power electronic device power circuit model; Obtaining the valid dynamic link library model includes: A power circuit model of a power electronic device, a substation transformer model, and a medium-voltage network node equivalent voltage source model connected in series are provided, the voltage and current at a first connection point between the power electronic device power circuit model and the substation transformer model are output to a real controller of the power electronic device via an analog output board in a real-time simulator, and a first response result of the first connection point is obtained when a digital signal in the power circuit model of the power electronic device interacts with the real controller of the power electronic device via a digital input / output board in the real-time simulator; Construct a dynamic link library model for power electronic equipment controller source code packaging; Providing a power electronic device power loop model, a substation transformer model, and a medium-voltage network node equivalent voltage source model connected in series, directly outputting the voltage and current at a second connection point between the power electronic device power loop model and the substation transformer model to a dynamic link library model encapsulated by the power electronic device controller source code, and obtaining a second response result of the second connection point when a digital signal in the power electronic device power loop model directly interacts with the dynamic link library model encapsulated by the power electronic device controller source code; Determine whether the difference between the first response result and the second response result is less than a preset error value; if so, determine that the dynamic link library model of the power electronic device controller source code package is a valid dynamic link library model of the controller source code package; if not, reconstruct the dynamic link library model of the power electronic device controller source code package.

8. The method for testing characteristics of a feeder terminal according to claim 7, wherein: Before using the substation intelligent terminal to adjust the distribution low-voltage substation model to enter the first steady-state operating condition before testing, the method further includes: A first ground fault is set on the low-voltage side or the medium-voltage side of the transformer model in the substation, and the ideal response result is the ideal response result under the first ground fault; The first grounding fault includes any one of a single-phase grounding fault, a two-phase grounding fault, an interphase short circuit fault and a three-phase grounding fault, or any combination thereof.

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