1. A system adapted for use in a hybrid dc power transmission real-time dynamic simulation test, the system comprising:

the real-time digital simulation unit simulates the operating characteristics of an alternating current-direct current power grid, controls output according to the voltage or current of the physical simulation unit, and controls the boundary condition for realizing the real-time dynamic simulation test through the digital physical simulation interface unit;

the digital physical simulation interface unit is connected with the real-time digital simulation unit and the physical simulation unit and is used for interaction of energy and signals of the real-time digital unit and the physical simulation unit;

and the physical simulation unit simulates a target research object, sets a simulation test fault point aiming at the target research object, and performs real-time dynamic simulation test and test verification.

2. The system of claim 1, the digital physical simulation interface unit comprising: digital interface, D/A conversion, A/D conversion, component detection subunit, power interface and measuring element;

the digital interface is connected with the real-time digital simulation unit and used for controlling the boundary condition of the digital simulation unit, the D/A conversion and the A/D conversion are used for signal digital-to-analog conversion between the real-time digital simulation unit and the physical simulation unit, the component detection subunit is used for decomposing a direct current component and a harmonic component in a reference signal sent by the digital interface, the power interface is used for carrying out power amplification and real-time tracking on the direct current component and the harmonic component, and the measuring element is used for measuring the voltage and the current output by the physical simulation unit.

3. The system according to claim 1, wherein the physical simulation unit establishes a physical dynamic model of a converter transformer, a converter valve or a direct current line in the hybrid direct current power transmission system according to different experimental conditions, simulation requirements and an acquisition degree of a mathematical model, and the physical dynamic model simulates a target research object based on a scaling principle and retains a nonlinear characteristic of the target research object.

4. The system of claim 1, wherein the number of each of the real-time digital simulation unit, the digital physical simulation interface unit, and the physical simulation unit is at least 1.

5. The system of claim 1, the digital interface model of the digital interface employing a controlled current source model or a controlled voltage source model.

6. The system of claim 1, the power interface, comprising: the IGBT high-power converter and the MOSFET high-speed converter are respectively used for carrying out power amplification and real-time tracking on the direct current component and the harmonic component.

7. The system of claim 1, the measurement element, comprising: voltage hall sensor, current hall sensor and collection modulate circuit.

Background

Along with the improvement of the voltage grade and the enhancement of the through-current capacity of the flexible direct-current transmission system, the hybrid multi-terminal direct-current transmission technology that one end adopts the other end of the LCC or adopts the VSC at multiple ends obtains more and more attention, combines the technology and the economic advantage of the two types of direct-current transmission, not only saves the manufacturing cost and reduces the loss, but also can improve the stability of a receiving-end alternating-current system by utilizing the flexibility and the rapidity in the control of the VSC, and can effectively solve the problem of multi-feed-in direct-current commutation failure. At present, a hybrid direct-current power transmission network is in a rapid development stage, an effective simulation method needs to be adopted, an advanced simulation platform needs to be established, and the processes of operation, control, protection and the like of the hybrid direct-current power transmission network are deeply researched.

The physical simulation system has the advantages that physical characteristics are consistent with prototypes, electrical characteristics such as line inductance and capacitance can be reflected completely and truly in a comparative way, nonlinear characteristics of series-parallel connection work of the multi-level sub-modules can be truly reproduced, and the dynamic physical simulation system can truly reflect the operation characteristics of the actual system and is widely applied to relay protection research and test of the alternating current system. However, in the complex direct current power grid simulation research, pure physical simulation is often limited by scale, and compared with digital simulation, the pure physical simulation is not flexible enough, long in modeling period and large in engineering quantity.

Based on respective advantages and disadvantages of physical simulation and digital simulation, a real-time dynamic simulation technology of hybrid direct-current power transmission needs to be researched urgently, and theoretical research and test work of direct-current power transmission protection is perfected. The direct-current power transmission model framework is built by using a physical model, particularly, the physical model is adopted for simulating key elements in the framework, and the power cabinet is adopted for combining with a digital simulation controller for carrying out appropriate simplification equivalence on adjacent systems, so that the advantages of accuracy of the physical simulation model and flexibility in modeling of the digital simulation controller are achieved, and the test system taking dynamic simulation as a core is realized. On the basis, a test method for the hybrid direct-current transmission control protection equipment is researched, and the method has important significance in promoting the construction of a hybrid power grid and improving the project operation quality.

Disclosure of Invention

In order to solve the above problems, the present invention provides a system suitable for a hybrid dc power transmission real-time dynamic simulation test, comprising:

the real-time digital simulation unit simulates the operating characteristics of an alternating current-direct current power grid, controls output according to the voltage or current of the physical simulation unit, and controls the boundary condition for realizing the real-time dynamic simulation test through the digital physical simulation interface unit;

the digital physical simulation interface unit is connected with the real-time digital simulation unit and the physical simulation unit and is used for interaction of energy and signals of the real-time digital unit and the physical simulation unit;

and the physical simulation unit simulates a target research object, sets a simulation test fault point aiming at the target research object, and performs real-time dynamic simulation test and test verification.

Optionally, the digital physical simulation interface unit includes: digital interface, D/A conversion, A/D conversion, component detection subunit, power interface and measuring element;

the digital interface is connected with the real-time digital simulation unit and used for controlling the boundary condition of the digital simulation unit, the D/A conversion and the A/D conversion are used for signal digital-to-analog conversion between the real-time digital simulation unit and the physical simulation unit, the component detection subunit is used for decomposing a direct current component and a harmonic component in a reference signal sent by the digital interface, the power interface is used for carrying out power amplification and real-time tracking on the direct current component and the harmonic component, and the measuring element is used for measuring the voltage and the current output by the physical simulation unit.

Optionally, the physical simulation unit establishes a physical dynamic model of the converter transformer, the converter valve or the dc line in the hybrid dc power transmission system according to different experimental conditions, simulation requirements and the degree of obtaining the mathematical model, where the physical dynamic model simulates a target research object based on a scaling principle and retains a nonlinear characteristic of the target research object.

Optionally, the number of each unit in the real-time digital simulation unit, the digital physical simulation interface unit, and the physical simulation unit is at least 1.

Optionally, the digital interface model of the digital interface adopts a controlled current source model or a controlled voltage source model.

Optionally, the power interface includes: the IGBT high-power converter and the MOSFET high-speed converter are respectively used for carrying out power amplification and real-time tracking on the direct current component and the harmonic component.

Optionally, the measuring element comprises: voltage hall sensor, current hall sensor and collection modulate circuit.

The invention has the advantages of accurate physical simulation model and flexible modeling of the digital simulation controller, and realizes the test system taking the simulation of the moving die as the core.

The invention provides a high-power system-level hybrid simulation platform and an effective important technical means for the research of novel equipment, equipment network access test, system safe and stable operation and the like in the future direct-current transmission network, and has wide application prospect.

Drawings

FIG. 1 is a block diagram of the system of the present invention;

FIG. 2a is a schematic diagram of an MMC converter valve and a converter transformer test model of the system of the present invention;

FIG. 2b is a model diagram of an LCC converter valve and converter transformer test of the system of the present invention;

FIG. 2c is a diagram of a DC line test model of the system of the present invention;

FIG. 3 is a diagram of the digital physical simulation interface unit of the system of the present invention.

Detailed Description

The exemplary embodiments of the present invention will now be described with reference to the accompanying drawings, however, the present invention may be embodied in many different forms and is not limited to the embodiments described herein, which are provided for complete and complete disclosure of the present invention and to fully convey the scope of the present invention to those skilled in the art. The terminology used in the exemplary embodiments illustrated in the accompanying drawings is not intended to be limiting of the invention. In the drawings, the same units/elements are denoted by the same reference numerals.

Unless otherwise defined, terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Further, it will be understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense.

The invention provides a system suitable for a hybrid direct-current power transmission real-time dynamic simulation test, as shown in fig. 1, comprising: the system comprises a real-time digital simulation unit, a digital physical simulation interface unit and a physical simulation unit;

the real-time digital simulation unit simulates the operating characteristics of an alternating current-direct current power grid based on an electromechanical or electromagnetic transient real-time simulation technology, and is used for controlling the self output according to the voltage or current signal measured by the measuring element to realize the boundary condition of a digital side subsystem;

the digital physical simulation interface unit is used for connecting the real-time digital simulation unit and the physical simulation unit and realizing the interaction of energy and signals between digital and physical systems according to a certain algorithm;

the physical simulation unit simulates a research object based on a scaling equivalence principle, improves the simulation precision of a complex nonlinear system, can set a simulation test fault point and is used for carrying out simulation test and verification of related protection;

as shown in fig. 2a, a preferred structure of the system according to the embodiment of the present invention includes two real-time digital simulation units, one physical simulation unit and two digital physical simulation interface units. The real-time digital simulation unit 1 includes: the system comprises a direct current circuit, an LCC side converter valve, a converter transformer, a filter and a back alternating current system. The real-time digital simulation unit 2 includes: an AC system behind the MMC side. The digital physical simulation interface units are respectively positioned on the right side of the direct-current line and the right side of the MMC side converter transformer. The method can be used for carrying out fault simulation of the MMC converter valve and the converter transformer and related control protection system test tests.

As shown in fig. 2b, a preferred structure of the system according to the embodiment of the present invention includes two real-time digital simulation units, one physical simulation unit and two digital physical simulation interface units. The real-time digital simulation unit 1 includes: direct current circuit, MMC side converter valve, converter transformer and the alternating current system behind. The real-time digital simulation unit 2 includes: LCC side filter and back AC system. The digital physical simulation interface units are respectively positioned on the right side of the direct-current line and the right side of the LCC side converter transformer. The test device can be used for carrying out LCC converter valve, converter transformer fault simulation and related control protection system test tests.

As shown in fig. 2c, a preferred structure of the system according to the embodiment of the present invention includes two real-time digital simulation units, one physical simulation unit and two digital physical simulation interface units. The real-time digital simulation unit 1 includes: LCC side converter valves, converter transformers, filters and the back AC system. The real-time digital simulation unit 2 includes: MMC side converter valve, converter transformer and back AC system. The digital physical simulation interface units are respectively positioned at two sides of the direct current circuit. The method can be used for fault simulation of the open DC line and test tests of related control protection systems.

As shown in fig. 3, the digital physical hybrid simulation interface unit provided by the present invention includes: digital interface, D/A conversion, A/D conversion, component detection subunit, power interface and measurement element.

The digital interface is connected with the digital side subsystem, the digital interface model adopts a controlled current source model (or controlled voltage source) model, and the output of the controlled current source (or controlled voltage source) is controlled according to the current (or voltage) signal uploaded by the receiving measuring element, so that the boundary condition of the digital side subsystem is realized. And when the equivalent impedance of the digital side subsystem is smaller than that of the physical side subsystem, the digital interface model adopts a controlled current source model, and conversely, when the equivalent impedance of the digital side subsystem is larger than that of the physical side subsystem, the digital interface model adopts a controlled voltage source model. The real-time digital simulation platform comprises a controlled current source module and a controlled voltage source module, so that a corresponding digital interface model can be established in the real-time digital simulation platform relatively easily.

The D/a conversion is used for signal digital-to-analog conversion, and converts a digital reference current (or voltage) signal of a digital side subsystem into an analog signal when transmitting a signal. Because the delay of the hybrid simulation interface system exists, the digital-to-analog conversion time is required to be completed within one simulation step length, and therefore, the digital-to-analog conversion module can select a parallel digital-to-analog conversion module with high resolution, high sampling rate and small hardware delay. In a common real-time digital simulation platform (such as RTDS), a matched D/A conversion integrated board card is arranged, and only correct configuration is needed when the integrated board card is used.

The A/D conversion is used for signal analog-to-digital conversion, and when the signal is uploaded, the voltage and the current quantity of the physical side subsystem port measured by the measuring element are converted into digital signals. The requirements and implementation are the same as for D/a conversion.

The component detection subunit is used for decomposing the direct current component and the harmonic component in the reference signal issued by the digital interface and outputting the corresponding direct current component and the corresponding harmonic component. In order to ensure accuracy, the sum of the decomposed direct current component and the harmonic component needs to be equal to the original issued reference signal.

The power interface comprises an IGBT high-power converter and an MOSFET high-speed converter which are respectively used for carrying out power amplification and real-time tracking on the direct current component and the harmonic component. And the output ends of the IGBT high-power converter and the MOSFET high-speed converter are connected in series and then connected with the physical side subsystem. The power interface model is corresponding to the digital interface model, and if the digital interface adopts the controlled current source (or controlled voltage source) model, the power interface is controlled to be the controlled voltage source (or controlled current source) model. The IGBT high-power converter needs to track and restore direct-current components, and because the content of the direct-current components is high, a multi-level parallel topological structure based on a high-power IGBT module and a carrier phase-shifting PWM (pulse width modulation) method can be adopted to realize direct-current high-power tracking and restoring; the MOSFET high-speed converter needs to track and restore harmonic components, because the harmonic frequency is high but the content is less, a multistage series-parallel connection topological structure based on an MOSFET module with higher switching frequency and a carrier phase-shifting PWM (pulse-width modulation) method can be adopted, the switching frequency is very high, and the harmonic restoration and dynamic response performance can be ensured.

The measuring element is used for measuring the voltage and the current of the physical side subsystem port, comprises a voltage Hall sensor, a current Hall sensor and a related acquisition conditioning circuit, and is required to have the minimum time delay and the minimum dynamic response time in order to ensure real-time acquisition. The collected voltage and current information is uploaded to a digital interface model to control the output state of the digital interface, and is also uploaded to a related control system to serve as feedback quantity of the port state of the physical side subsystem.

And the physical simulation unit is used for establishing a converter transformer, a converter valve or a direct-current line physical dynamic model in the hybrid direct-current power transmission system according to different experimental conditions, simulation requirements and the acquisition degree of the mathematical model. The physical model simulates a research object based on a scaling principle, retains the nonlinear characteristic of the research object and effectively improves the accuracy of a simulation result.

Compared with the closest prior art, the system provided by the invention has the following beneficial effects:

the system has the advantages of accurate physical simulation model and flexible modeling of the digital simulation controller, realizes a test system taking dynamic simulation as a core, decomposes a reference signal of a digital side subsystem into direct current and harmonic components through a component detection subunit, respectively controls an IGBT high-power converter and an MOSFET high-speed converter, and has no theoretical error between the output quantity of the power interface and the reference signal obtained after the two are connected in series; meanwhile, the broadband characteristic of the MOSFET high-speed converter can restore more harmonic details, and the accuracy of hybrid simulation is improved.

The application of hybrid simulation is expanded. The system provided by the invention can reasonably select the modeling method and the interface algorithm of the real-time digital simulation unit and the physical simulation unit according to different experimental conditions, simulation requirements and the acquisition degree of a mathematical model, meets the test requirements of the converter transformer, the converter valve or the direct current circuit and the protection thereof in the hybrid direct current power transmission system on the premise of ensuring the accuracy of hybrid simulation, and effectively expands the application scene of the hybrid simulation. The high-power system-level hybrid simulation platform and the effective important technical means are provided for the research of novel equipment, equipment network access test, system safe and stable operation and the like in the future direct-current transmission network, and the application prospect is wide.

As will be appreciated by one skilled in the art, embodiments of the present invention may be provided as a method, system, or computer program product. Accordingly, the present invention may 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, and the like) having computer-usable program code embodied therein. The scheme in the embodiment of the invention can be realized by adopting various computer languages, such as object-oriented programming language Java and transliterated scripting language JavaScript.

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 will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

While preferred embodiments of the present invention have been described, additional variations and modifications in those embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. Therefore, it is intended that the appended claims be interpreted as including preferred embodiments and all such alterations and modifications as fall within the scope of the invention.

It will be apparent to those skilled in the art that various changes and modifications may be made in the present invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.