Simplification method for switching function of dynamic phasor model of high-voltage direct-current power transmission system

Abstract

The invention relates to a method for simplifying a switching function of a dynamic phasor model of a high-voltage direct-current transmission system, and the method comprises the steps: building an LCC-HVDC dynamic phasor model of a target high-voltage direct-current transmission system; extracting a switching function of a time domain expression form in the LCC-HVDC dynamic phasor model; and based on a preset switching function dynamic vector simplification principle, determining a target order number of the switching function, and establishing a simplified LCC-HVDC dynamic vector model corresponding to the LCC-HVDC dynamic phasor model according to the target order number. Therefore, the problems that an existing ultra-high-voltage direct-current system dynamic vector model utilizes infinite series to express a switching function, an exact simplified analytical expression of the switching function does not exist, the physical significance of the prior art is difficult to verify, and expansion and application of a dynamic phasor time domain method are greatly hindered are solved.

Description

Technical Field

[0001] The present application relates to the technical field of direct current transmission of power systems, and in particular to a method for simplifying a switching function of a dynamic phasor model of a high-voltage direct current transmission system. Background Art

[0002] Ultra-high voltage direct current (UHVDC) transmission has been widely used and developed in my country due to its large transmission capacity, flexible control characteristics, and good long-distance transmission economy. Among them, line commutated converter high voltage direct current (LCC-HVDC) transmission has gradually become the main component of my country's direct current transmission due to its low cost and huge transmission capacity.

[0003] However, LCC-HVDC uses semi-controllable devices, thyristors, as commutation elements. Their semi-controllable characteristics lead to the natural risk of commutation failure in the converter. A simple AC fault at the near-end outlet of the receiving AC busbar is likely to cause commutation failure in the inverter, leading to a series of chain failures such as DC lockout, power flow transfer, and overload, which seriously threaten the safe and stable operation of my country's power grid.

[0004] In order to accurately analyze the transient response characteristics of the DC transmission system under the AC fault at the receiving end, the existing technology can use the dynamic phasor model to make a frequency assumption on the switching function, and then analytically express the step switching function with multiple sinusoidal functions. The switching function is directly multiplied by the AC electrical quantity in the time domain to obtain the DC electrical quantity.

[0005] However, the existing UHVDC system dynamic vector model uses infinite series to express the switching function, and there is no exact simplified analytical expression of the switching function. It is difficult to verify the physical meaning of the existing technology, which greatly hinders the expansion and application of the dynamic phasor time domain method and needs to be solved urgently. Summary of the Invention

[0006] The present application provides a method for simplifying the switching function of a dynamic phasor model of a high-voltage direct current transmission system to address the problems that the existing dynamic vector model of an ultra-high voltage direct current system uses infinite series to express the switching function, does not have an exact simplified analytical expression for the switching function, makes it difficult to verify the physical meaning of the existing technology, and greatly hinders the expansion and application of the dynamic phasor time-domain method.

[0007] In a first aspect, an embodiment of the present application provides a method for simplifying a switching function of a dynamic phasor model of a high-voltage direct current (HVDC) transmission system, comprising the following steps: establishing an LCC-HVDC dynamic phasor model of a target high-voltage direct current (HVDC) transmission system; extracting a switching function expressed in a time domain from the LCC-HVDC dynamic phasor model; determining a target order of the switching function based on a preset switching function dynamic vector simplification principle, and establishing a simplified LCC-HVDC dynamic vector model corresponding to the LCC-HVDC dynamic phasor model according to the target order.

[0008] Optionally, in one embodiment of the present application, extracting the switching function in the time domain expression form in the LCC-HVDC dynamic phasor model includes: extracting the A-phase voltage switching function, current switching function, B-phase switching function and C-phase switching function in the LCC-HVDC dynamic phasor model, and obtaining the K-order dynamic phasor expressions corresponding to the A-phase voltage switching function and the current switching function; determining the K-order dynamic phasor expressions of the B-phase switching function and the C-phase switching function based on the dynamic phasor expression of the A-phase voltage switching function; and performing time domain conversion on the K-order dynamic phasor expressions of the A-phase voltage switching function, the current switching function, the B-phase switching function and the C-phase switching function respectively to obtain the A-phase voltage switching function, the current switching function, the B-phase switching function and the C-phase switching function in time domain expression form.

[0009] Optionally, in one embodiment of the present application, determining the target order of the switching function based on a preset dynamic vector simplification principle of the switching function includes: determining the AC voltage frequency order k of the target high-voltage direct current transmission system, and obtaining the K+k harmonic term and the Kk harmonic term of the LCC-HVDC dynamic phasor model based on the AC voltage frequency order; and determining the target order of the switching function according to the K+k harmonic term, the Kk harmonic term and a preset main harmonic transfer law.

[0010] Optionally, in one embodiment of the present application, the mathematical expression of the simplified LCC-HVDC dynamic vector model is:

[0011]

[0012] Wherein, α represents the trigger delay angle of the LCC converter; k represents the frequency of the AC voltage; U k Indicates the amplitude of the kth harmonic of the AC voltage; represents the initial phase of the kth harmonic of the AC voltage; μ represents the arc extinction advance angle of the LCC converter; ω represents the angular velocity; and t represents time.

[0013] According to a second aspect of the present application, an embodiment provides a device for simplifying a switching function of a dynamic phasor model of a high-voltage direct current (HVDC) transmission system, including: a modeling module for establishing an LCC-HVDC dynamic phasor model of a target high-voltage direct current (HVDC) transmission system; an extraction module for extracting a switching function expressed in a time domain from the LCC-HVDC dynamic phasor model; and a simplification module for determining a target order of the switching function based on a preset switching function dynamic vector simplification principle, and establishing a simplified LCC-HVDC dynamic vector model corresponding to the LCC-HVDC dynamic phasor model according to the target order.

[0014] Optionally, in one embodiment of the present application, the extraction module includes: an acquisition unit, used to extract the A-phase voltage switching function, current switching function, B-phase switching function and C-phase switching function in the LCC-HVDC dynamic phasor model, and obtain the K-order dynamic phasor expression corresponding to the A-phase voltage switching function and the current switching function; a first determination unit, used to determine the K-order dynamic phasor expression of the B-phase switching function and the C-phase switching function based on the dynamic phasor expression of the A-phase voltage switching function; a conversion unit, used to perform time domain conversion on the K-order dynamic phasor expressions of the A-phase voltage switching function, the current switching function, the B-phase switching function and the C-phase switching function respectively, so as to obtain the A-phase voltage switching function, the current switching function, the B-phase switching function and the C-phase switching function in time domain expression.

[0015] Optionally, in one embodiment of the present application, the simplification module includes: a second determination unit, configured to determine an AC voltage frequency order k of the target high-voltage direct current transmission system, and obtain a K+k harmonic term and a Kk harmonic term of the LCC-HVDC dynamic phasor model based on the AC voltage frequency order; and a third determination unit, configured to determine a target order of the switching function based on the K+k harmonic term, the Kk harmonic term, and a preset main harmonic transfer law.

[0016] Optionally, in one embodiment of the present application, the mathematical expression of the simplified LCC-HVDC dynamic vector model is:

[0017]

[0018] Wherein, α represents the trigger delay angle of the LCC converter; k represents the frequency of the AC voltage; U k Indicates the amplitude of the kth harmonic of the AC voltage; represents the initial phase of the kth harmonic of the AC voltage; μ represents the arc extinction advance angle of the LCC converter; ω represents the angular velocity; and t represents time.

[0019] A third aspect of the present application provides an electronic device, comprising: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the method for simplifying the switching function of the dynamic phasor model of the high-voltage direct current transmission system as described in the above embodiment.

[0020] In a fourth aspect, an embodiment of the present application provides a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the above-mentioned method for simplifying the switching function of the dynamic phasor model of the high-voltage direct current transmission system.

[0021] A fifth aspect of the present application provides a computer program product, including a computer program, which is executed to implement the above-mentioned method for simplifying the switching function of the dynamic phasor model of the high-voltage direct current transmission system.

[0022] Therefore, the embodiments of the present application have the following beneficial effects:

[0023] The embodiments of the present application can be achieved by establishing an LCC-HVDC dynamic phasor model of the target high-voltage direct current transmission system; extracting the switching function in the time domain expression form in the LCC-HVDC dynamic phasor model; determining the target order of the switching function based on the preset switching function dynamic vector simplification principle, and establishing a simplified LCC-HVDC dynamic vector model corresponding to the LCC-HVDC dynamic phasor model according to the target order. The present application simplifies the switching function into a sinusoidal function based on the analytical expression of the switching function and its physical meaning, which can not only reduce the amount of calculation required for modeling the switching function, but also describe the main harmonic transmission law of the AC / DC system, thereby improving the calculation speed while ensuring a certain degree of calculation accuracy. Thus, the existing UHVDC system dynamic vector model solves the problem that the switching function is expressed by an infinite series, there is no exact simplified analytical expression of the switching function, it is difficult to verify the physical meaning of the existing technology, and it greatly hinders the expansion and application of the dynamic phasor time domain method.

[0024] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0026] Figure 1 A flowchart of a method for simplifying a switching function of a dynamic phasor model of a high-voltage direct current transmission system according to an embodiment of the present application;

[0027] Figure 2A schematic diagram of a dynamic phasor time domain method calculation flow chart provided for one embodiment of the present application;

[0028] Figure 3 A simplified waveform diagram of a switching function based on a dynamic phasor method is provided for one embodiment of the present application;

[0029] Figure 4 This is an example diagram of a simplified device for a dynamic phasor model switching function of a high-voltage direct current transmission system according to an embodiment of the present application;

[0030] Figure 5 A schematic diagram of the structure of an electronic device provided in an embodiment of the present application.

[0031] Among them, 10 is a simplified device for the switching function of the dynamic phasor model of the high-voltage direct current transmission system; 100 is a modeling module, 200 is an extraction module, 300 is a simplification module; 501 is a memory, 502 is a processor, and 503 is a communication interface. DETAILED DESCRIPTION

[0032] The following describes in detail embodiments of the present application, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present application, and should not be construed as limiting the present application.

[0033] The following describes a method for simplifying the switching function of a dynamic phasor model of a high-voltage direct current (HVDC) transmission system according to an embodiment of the present application, with reference to the accompanying drawings. To address the issues mentioned in the background art, the present application provides a method for simplifying the switching function of a dynamic phasor model of a high-voltage direct current (HVDC) transmission system. The method comprises establishing an LCC-HVDC dynamic phasor model of a target HVDC transmission system; extracting the switching function in the time domain from the LCC-HVDC dynamic phasor model; determining the target order of the switching function based on a preset dynamic vector simplification principle for the switching function; and establishing a simplified LCC-HVDC dynamic vector model corresponding to the LCC-HVDC dynamic phasor model based on the target order. Based on the analytical expression and physical meaning of the switching function, the present application simplifies the switching function into a sinusoidal function. This not only reduces the computational complexity of the switching function modeling, but also describes the main harmonic transmission laws of the AC / DC system, thereby improving computational speed while ensuring a certain degree of computational accuracy. This method addresses the problems of existing UHVDC system dynamic vector models that use infinite series to express the switching function, lack an exact simplified analytical expression for the switching function, and are difficult to verify the physical meaning of the existing technology, which greatly hinders the expanded application of dynamic phasor time-domain methods.

[0034] Specifically, Figure 1This is a flow chart of a method for simplifying the switching function of a dynamic phasor model of a high-voltage direct current transmission system provided in an embodiment of the present application.

[0035] like Figure 1 As shown, the simplified method for the switching function of the dynamic phasor model of the HVDC transmission system includes the following steps:

[0036] In step S101, a LCC-HVDC dynamic phasor model of a target high voltage direct current transmission system is established.

[0037] In step S102 , a switching function in a time domain expression form is extracted from the LCC-HVDC dynamic phasor model.

[0038] The embodiment of the present application can first establish the LCC-HVDC dynamic phasor model u of the high voltage direct current transmission system d =S va u a +S vb u b +S vc u c , and extract the switching function of the time domain expression of the model.

[0039] Optionally, in one embodiment of the present application, extracting the switching function in the time domain expression form in the LCC-HVDC dynamic phasor model includes: extracting the A-phase voltage switching function, current switching function, B-phase switching function and C-phase switching function in the LCC-HVDC dynamic phasor model, and obtaining the K-order dynamic phasor expressions corresponding to the A-phase voltage switching function and the current switching function; determining the K-order dynamic phasor expressions of the B-phase switching function and the C-phase switching function based on the dynamic phasor expression of the A-phase voltage switching function; and performing time domain conversion on the K-order dynamic phasor expressions of the A-phase voltage switching function, the current switching function, the B-phase switching function and the C-phase switching function, respectively, to obtain the A-phase voltage switching function, the current switching function, the B-phase switching function and the C-phase switching function in the time domain expression form.

[0040] It should be noted that the embodiment of the present application can establish the LCC-HVDC dynamic phasor model u d =S va u a +S vb u b +S vc u c ,like Figure 2 As shown, the switching function is extracted, where the A phase voltage switching function S va and the current switching function S ia The K-order dynamic phasor expression is:

[0041]

[0042] The expressions of the switching functions of phases B and C are similar to those of phase A, with phase offsets of -2π / 3 and 2π / 3 from phase A, respectively. Therefore, the K-order dynamic phasor expressions of the switching functions of phases B and C are:

[0043]

[0044] Afterwards, the embodiment of the present application can transform the switching function phasor value back to the time domain value. Taking the voltage switching function as an example, the time domain value of the three-phase voltage switching function is:

[0045]

[0046] Where θ represents the synchronization phase of the PLL output.

[0047] Therefore, the embodiments of the present application provide reliable guidance and basis for the subsequent simplification of the switching function of the dynamic phasor model of the high-voltage direct current transmission system by constructing the LCC-HVDC dynamic phasor model and extracting the corresponding time domain expression switching function.

[0048] In step S103, based on a preset switching function dynamic vector simplification principle, a target order of the switching function is determined, and a simplified LCC-HVDC dynamic vector model corresponding to the LCC-HVDC dynamic phasor model is established according to the target order.

[0049] Furthermore, the embodiment of the present application selects the order K of the switching function based on the principle of simplification of the dynamic vector of the switching function. In the embodiment of the present application, K=1 is generally selected, that is, the voltage switching function is simplified to a sine function; then, the embodiment of the present application can obtain a simplified LCC-HVDC dynamic vector model according to the selected K value, such as Figure 3 shown.

[0050] Therefore, the embodiments of the present application explicitly provide a simplified expression of the LCC-HVDC dynamic vector model through the principle of selecting the order of the infinite series switching function simplification of the dynamic phasor model. This expression has clear physical meaning and can describe the main harmonic transmission laws of AC and DC systems. It can not only reduce the computational complexity of switching function modeling and improve the calculation speed, but also ensure a certain degree of calculation accuracy.

[0051] Optionally, in one embodiment of the present application, based on a preset switching function dynamic vector simplification principle, the target order of the switching function is determined, including: determining the AC voltage frequency order k of the target high-voltage direct current transmission system, and based on the AC voltage frequency order, obtaining the K+k harmonic term and the Kk harmonic term of the LCC-HVDC dynamic phasor model; determining the target order of the switching function according to the K+k harmonic term, the Kk harmonic term and the preset main harmonic transfer law.

[0052] In the embodiment of the present application, the principle and process for determining the order K of the switching function are as follows:

[0053] Assuming that the frequency of the AC voltage is k, the K-order phasor expression of the switching function takes phase A as an example:

[0054]

[0055] In the embodiment of the present application, the A phase S in the LCC-HVDC dynamic phasor model can be first va u a Analyze and then extend to three phases. Without simplifying the switching function and AC voltage, phase A S va u a , as shown below:

[0056]

[0057] Right now:

[0058]

[0059] It should be noted that the dynamic phasor model is mainly divided into two types of cosine terms: K+k subharmonic term and Kk subharmonic term. The mathematical expression of the K+k subharmonic term is as follows:

[0060] Phase A:

[0061] Phase B:

[0062] Phase C:

[0063] The mathematical expression of the Kk subharmonic term is as follows:

[0064] Phase A:

[0065] Phase B:

[0066] Phase C:

[0067] For the K+k harmonic term, it can be seen that if K+1 is not a multiple of 3, the three-phase sum is 0, otherwise, the sum is not 0. For the Kk harmonic term, it can be seen that if K-1 is not a multiple of 3, the three-phase sum is 0, otherwise, the sum is not 0.

[0068] It is understandable that the simplification of the dynamic phasor model needs to be able to characterize the main coupling relationship between AC and DC, combined with the main harmonic transmission law of AC and DC systems: the DC component and second harmonic component of the DC system mainly come from the fundamental frequency component and third harmonic component of the AC system, respectively; therefore, the embodiment of the present application can select the AC voltage frequency k = 1, 3. According to the main harmonic transmission law, K must meet the following conditions:

[0069]

[0070] Therefore, the embodiment of the present application can solve K=1, that is, simplify the voltage switching function to a sine function.

[0071] Therefore, the embodiment of the present application simplifies the switching function into a sinusoidal function based on the analytical expression of the switching function and its physical meaning, thereby effectively reducing the computational complexity of the switching function modeling, and describes the main harmonic transmission laws of the AC and DC systems, thereby improving the calculation speed while ensuring a certain calculation accuracy.

[0072] Optionally, in one embodiment of the present application, the mathematical expression of the simplified LCC-HVDC dynamic vector model is:

[0073]

[0074] Where α represents the trigger delay angle of the LCC converter; k represents the AC voltage frequency; U k Indicates the amplitude of the kth harmonic of the AC voltage; represents the initial phase of the kth harmonic of the AC voltage; μ represents the arc extinction advance angle of the LCC converter; ω represents the angular velocity; and t represents time.

[0075] In the embodiment of the present application, according to the above-selected K value (taking K=1 as an example), a simplified LCC-HVDC dynamic vector model is obtained, as shown in the following formula:

[0076]

[0077] Where α represents the trigger delay angle of the LCC converter; k represents the AC voltage frequency; U k Indicates the amplitude of the kth harmonic of the AC voltage; represents the initial phase of the kth harmonic of the AC voltage; μ represents the arc extinction advance angle of the LCC converter; ω represents the angular velocity; and t represents time.

[0078] Therefore, the embodiment of the present application obtains a simplified LCC-HVDC dynamic vector model according to the selected order, thereby effectively simplifying the switching function of the dynamic phasor model of the high-voltage direct current transmission system and promoting the expanded application of the dynamic phasor time domain method.

[0079] According to the method for simplifying the switching function of the dynamic phasor model of the high-voltage direct current transmission system proposed in the embodiment of the present application, an LCC-HVDC dynamic phasor model of the target high-voltage direct current transmission system is established; the switching function in the time domain expression form in the LCC-HVDC dynamic phasor model is extracted; based on the preset switching function dynamic vector simplification principle, the target order of the switching function is determined, and a simplified LCC-HVDC dynamic vector model corresponding to the LCC-HVDC dynamic phasor model is established according to the target order. Based on the analytical expression of the switching function and its physical meaning, the present application simplifies the switching function into a sine function, which can not only reduce the amount of calculation for the switching function modeling, but also describe the main harmonic transmission law of the AC / DC system, thereby improving the calculation speed while ensuring a certain degree of calculation accuracy.

[0080] Next, a simplified device for a switching function of a dynamic phasor model of a high-voltage direct current transmission system proposed in an embodiment of the present application will be described with reference to the accompanying drawings.

[0081] Figure 4 It is a block diagram of a simplified device for a switching function of a dynamic phasor model of a high-voltage direct current transmission system according to an embodiment of the present application.

[0082] like Figure 4 As shown, the device 10 for simplifying the switching function of the dynamic phasor model of the HVDC transmission system includes: a modeling module 100 , an extraction module 200 and a simplification module 300 .

[0083] The modeling module 100 is used to establish an LCC-HVDC dynamic phasor model of the target high-voltage direct current transmission system.

[0084] The extraction module 200 is used to extract the switching function in the time domain expression form in the LCC-HVDC dynamic phasor model.

[0085] The simplification module 300 is configured to determine a target order of the switching function based on a preset switching function dynamic vector simplification principle, and to establish a simplified LCC-HVDC dynamic vector model corresponding to the LCC-HVDC dynamic phasor model according to the target order.

[0086] Optionally, in one embodiment of the present application, the extraction module 200 includes: an acquisition unit, a first determination unit, and a conversion unit.

[0087] The acquisition unit is used to extract the A-phase voltage switching function, current switching function, B-phase switching function and C-phase switching function in the LCC-HVDC dynamic phasor model, and obtain the K-order dynamic phasor expressions corresponding to the A-phase voltage switching function and current switching function.

[0088] The first determining unit is used to determine the K-order dynamic phasor expressions of the B-phase switching function and the C-phase switching function according to the dynamic phasor expression of the A-phase voltage switching function.

[0089] The conversion unit is used to perform time domain conversion on the K-order dynamic phasor expressions of the A-phase voltage switching function, current switching function, B-phase switching function and C-phase switching function respectively to obtain the A-phase voltage switching function, current switching function, B-phase switching function and C-phase switching function in time domain expression.

[0090] Optionally, in one embodiment of the present application, the simplification module 300 includes: a second determination unit and a third determination unit.

[0091] The second determining unit is configured to determine an AC voltage frequency order k of the target HVDC transmission system, and obtain K+k harmonic terms and Kk harmonic terms of the LCC-HVDC dynamic phasor model based on the AC voltage frequency order.

[0092] The third determining unit is used to determine the target order of the switching function according to the K+k harmonic term, the Kk harmonic term and the preset main harmonic transfer law.

[0093] Optionally, in one embodiment of the present application, the mathematical expression of the simplified LCC-HVDC dynamic vector model is:

[0094]

[0095] Where α represents the trigger delay angle of the LCC converter; k represents the AC voltage frequency; U k Indicates the amplitude of the kth harmonic of the AC voltage; represents the initial phase of the kth harmonic of the AC voltage; μ represents the arc extinction advance angle of the LCC converter; ω represents the angular velocity; and t represents time.

[0096] It should be noted that the aforementioned explanation of the embodiment of the method for simplifying the switching function of the dynamic phasor model of the HVDC transmission system is also applicable to the simplified device for the switching function of the dynamic phasor model of the HVDC transmission system of this embodiment, and will not be repeated here.

[0097] According to the embodiment of the present application, a device for simplifying the switching function of the dynamic phasor model of the high-voltage direct current transmission system proposed includes a modeling module for establishing an LCC-HVDC dynamic phasor model of the target high-voltage direct current transmission system; an extraction module for extracting the switching function in the time domain expression form in the LCC-HVDC dynamic phasor model; a simplification module for determining the target order of the switching function based on a preset switching function dynamic vector simplification principle, and establishing a simplified LCC-HVDC dynamic vector model corresponding to the LCC-HVDC dynamic phasor model according to the target order. The present application simplifies the switching function into a sinusoidal function based on the analytical expression of the switching function and its physical meaning, which can not only reduce the amount of calculation for the switching function modeling, but also describe the main harmonic transfer law of the AC / DC system, thereby improving the calculation speed while ensuring a certain calculation accuracy.

[0098] Figure 5 This is a schematic diagram of the structure of an electronic device provided in an embodiment of the present application. The electronic device may include:

[0099] Memory 501 , processor 502 , and computer programs stored in the memory 501 and executable on the processor 502 .

[0100] When the processor 502 executes the program, the method for simplifying the switching function of the dynamic phasor model of the HVDC power transmission system provided in the above embodiment is implemented.

[0101] Furthermore, the electronic device further includes:

[0102] The communication interface 503 is used for communication between the memory 501 and the processor 502 .

[0103] The memory 501 is used to store computer programs that can be run on the processor 502 .

[0104] The memory 501 may include a high-speed RAM memory, and may also include a non-volatile memory (non-volatile memory), such as at least one disk memory.

[0105] If the memory 501, processor 502, and communication interface 503 are implemented independently, the communication interface 503, memory 501, and processor 502 can be connected to each other via a bus and communicate with each other. The bus can be an Industry Standard Architecture (ISA) bus, a Peripheral Component Interconnect (PCI) bus, or an Extended Industry Standard Architecture (EISA) bus. The bus can be divided into an address bus, a data bus, a control bus, etc. For ease of representation, Figure 5 Only one thick line is used in the diagram, but this does not mean that there is only one bus or one type of bus.

[0106] Optionally, in a specific implementation, if the memory 501, the processor 502 and the communication interface 503 are integrated on a chip, the memory 501, the processor 502 and the communication interface 503 can communicate with each other through an internal interface.

[0107] The processor 502 may be a central processing unit (CPU), an application specific integrated circuit (ASIC), or one or more integrated circuits configured to implement the embodiments of the present application.

[0108] An embodiment of the present application further provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the above-mentioned method for simplifying the switching function of the dynamic phasor model of the high-voltage direct current transmission system.

[0109] An embodiment of the present application further provides a computer program product, including a computer program. When the computer program is executed, it is used to implement the above-mentioned method for simplifying the switching function of the dynamic phasor model of the high-voltage direct current transmission system.

[0110] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or N embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and features of different embodiments or examples without contradiction.

[0111] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of technical features indicated. Thus, a feature specified as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of this application, "N" means at least two, for example, two, three, etc., unless otherwise specifically defined.

[0112] Any process or method description in a flowchart or otherwise described herein may be understood to represent a module, fragment or portion of code comprising one or N executable instructions for implementing a custom logical function or process step, and the scope of the preferred embodiments of the present application includes alternative implementations in which functions may be performed in a different order than shown or discussed, including performing functions in a substantially simultaneous manner or in a reverse order depending on the functions involved, which should be understood by those skilled in the art to which the embodiments of the present application pertain.

[0113] The logic and / or steps represented in the flowcharts or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing the logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (e.g., a computer-based system, a system including a processor, or other system that can fetch and execute instructions from an instruction execution system, apparatus, or device). For purposes of this specification, a "computer-readable medium" can be any device that can contain, store, communicate, propagate, or transport a program for use by, or in conjunction with, an instruction execution system, apparatus, or device. More specific examples (a non-exhaustive list) of computer-readable media include the following: an electrical connection with one or N wires (electronic devices), a portable computer disk cartridge (magnetic device), random access memory (RAM), read-only memory (ROM), erasable and programmable read-only memory (EPROM or flash memory), fiber optic devices, and a portable compact disc read-only memory (CDROM). In addition, the computer-readable medium may even be paper or other suitable medium on which the program is printed, since the program can be obtained electronically by optically scanning the paper or other medium and then editing, interpreting or processing it in other suitable ways as necessary, and then storing it in a computer memory.

[0114] It should be understood that various parts of the present application can be implemented using hardware, software, firmware, or a combination thereof. In the above embodiment, the N steps or methods can be implemented using software or firmware stored in a memory and executed by a suitable instruction execution system. If implemented using hardware, as in another embodiment, any one of the following technologies known in the art or a combination thereof can be used: a discrete logic circuit having a logic gate circuit for implementing a logic function on a data signal, an application-specific integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0115] Those skilled in the art will understand that all or part of the steps in the method of the above embodiment can be completed by instructing related hardware through a program, and the program can be stored in a computer-readable storage medium. When the program is executed, it includes one or a combination of the steps of the method embodiment.

[0116] In addition, the functional units in the various embodiments of the present application may be integrated into a processing module, or each unit may exist physically separately, or two or more units may be integrated into a module. The above-mentioned integrated module may be implemented in the form of hardware or in the form of a software functional module. If the integrated module is implemented in the form of a software functional module and sold or used as an independent product, it may also be stored in a computer-readable storage medium.

[0117] The storage medium mentioned above may be a read-only memory, a magnetic disk, or an optical disk, etc. Although the embodiments of the present application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present application. Persons skilled in the art may make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present application.

Claims

1. A method for simplifying the switching function of a dynamic phasor model of a high voltage direct current transmission system, characterized in that: The following steps are involved: Establish the LCC-HVDC dynamic phasor model of the target HVDC transmission system; Extracting a switching function in a time domain expression in the LCC-HVDC dynamic phasor model; Based on a preset switching function dynamic vector simplification principle, a target order of the switching function is determined, and a simplified LCC-HVDC dynamic vector model corresponding to the LCC-HVDC dynamic phasor model is established according to the target order.

2. The method according to claim 1, characterized in that The step of extracting the switching function in the time domain expression form in the LCC-HVDC dynamic phasor model comprises: Extracting the A-phase voltage switching function, the current switching function, the B-phase switching function and the C-phase switching function in the LCC-HVDC dynamic phasor model, and obtaining the K-order dynamic phasor expressions corresponding to the A-phase voltage switching function and the current switching function; Determine the K-order dynamic phasor expressions of the B-phase switching function and the C-phase switching function according to the dynamic phasor expression of the A-phase voltage switching function; The K-order dynamic phasor expressions of the A-phase voltage switching function, the current switching function, the B-phase switching function and the C-phase switching function are respectively transformed into time domain to obtain the A-phase voltage switching function, the current switching function, the B-phase switching function and the C-phase switching function in time domain expression.

3. The method according to claim 2, characterized in that The step of determining the target order of the switching function based on a preset switching function dynamic vector simplification principle includes: Determining an AC voltage frequency order k of the target high voltage direct current transmission system, and obtaining a K+k harmonic term and a Kk harmonic term of the LCC-HVDC dynamic phasor model based on the AC voltage frequency order; The target order of the switching function is determined according to the K+k harmonic term, the Kk harmonic term and a preset main harmonic transfer law.

4. The method according to claim 3, characterized in that The mathematical expression of the simplified LCC-HVDC dynamic vector model is: Wherein, α represents the trigger delay angle of the LCC converter; k represents the frequency of the AC voltage; U k Indicates the amplitude of the kth harmonic of the AC voltage; represents the initial phase of the kth harmonic of the AC voltage; μ represents the arc extinction advance angle of the LCC converter; ω represents the angular velocity; and t represents time.

5. A simplified device for switching functions of a dynamic phasor model of a high voltage direct current transmission system, characterized in that: include: A modeling module for establishing a LCC-HVDC dynamic phasor model of a target high-voltage direct current transmission system; An extraction module, used for extracting the switching function in the time domain expression form in the LCC-HVDC dynamic phasor model; The simplification module is used to determine the target order of the switching function based on a preset switching function dynamic vector simplification principle, and establish a simplified LCC-HVDC dynamic vector model corresponding to the LCC-HVDC dynamic phasor model according to the target order.

6. The device according to claim 5, characterized in that The extraction module comprises: An acquisition unit, used to extract the A-phase voltage switching function, the current switching function, the B-phase switching function and the C-phase switching function in the LCC-HVDC dynamic phasor model, and to acquire a K-order dynamic phasor expression corresponding to the A-phase voltage switching function and the current switching function; A first determining unit is used to determine the K-order dynamic phasor expressions of the B-phase switching function and the C-phase switching function according to the dynamic phasor expression of the A-phase voltage switching function; A conversion unit is used to perform time domain conversion on the K-order dynamic phasor expressions of the A-phase voltage switching function, the current switching function, the B-phase switching function and the C-phase switching function, respectively, so as to obtain the A-phase voltage switching function, the current switching function, the B-phase switching function and the C-phase switching function in the time domain expression form.

7. The device according to claim 6, characterized in that The simplified module includes: A second determining unit is used to determine an AC voltage frequency order k of the target high voltage direct current transmission system, and obtain a K+k harmonic term and a Kk harmonic term of the LCC-HVDC dynamic phasor model based on the AC voltage frequency order; The third determination unit is used to determine the target order of the switching function according to the K+k harmonic term, the Kk harmonic term and a preset main harmonic transfer law.

8. An electronic device, characterized in that: include: A memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the method for simplifying the switching function of the dynamic phasor model of the high-voltage direct current transmission system as described in any one of claims 1 to 4.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: The program is executed by a processor to implement the method for simplifying the switching function of a dynamic phasor model of a high-voltage direct current transmission system as described in any one of claims 1 to 4.

10. A computer program product, comprising a computer program, characterized in that The computer program is executed to implement the method for simplifying the switching function of the dynamic phasor model of the high-voltage direct current transmission system as claimed in any one of claims 1 to 4.

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