Phase selection method based on novel zero-sequence directional element and novel zero-sequence current dual-polarization criterion

Abstract

The invention discloses a phase selection method based on a novel zero-sequence directional element and a novel zero-sequence current dual-polarization criterion, and the method comprises the steps: calculating a zero-sequence voltage and a zero-sequence current according to a three-phase voltage vector and a three-phase current vector at a protection installation point; calculating a zero-sequence compensation voltage, a grounding compensation voltage and an interphase compensation voltage according to the zero-sequence voltage, the zero-sequence current and a preset high-resistance distance protection constant value; determining the fault direction of the protection mounting point according to the zero-sequence voltage, the zero-sequence current and a preset novel zero-sequence direction element criterion; when the fault direction is a positive direction fault, determining a fault phase according to a three-phase current vector and a preset sequence current absolute value phase selection element criterion; and determining a phase selection result according to the fault phase, the zero-sequence compensation voltage, the grounding compensation voltage, the inter-phase compensation voltage, the grounding fault criterion based on the sound phase compensation voltage amplitude, the zero-sequence current phase selection criterion of phase compensation voltage polarization and the zero-sequence current phase selection criterion of inter-phase compensation voltage polarization.

Description

Technical Field

[0001] The invention relates to the technical field of relay protection, and more specifically, to a phase selection method based on a novel zero-sequence directional element and a novel zero-sequence current dual-polarization criterion. Background Art

[0002] As one of the basic elements of relay protection, the action performance of the phase selection element is crucial for the fault phase discrimination of distance protection. Traditional phase selection elements select the fault phase after the protection has been determined as an internal fault. The phase selection elements widely used in engineering are usually current sequence component phase selection elements, which have the advantages of clear physical meaning and high phase selection sensitivity, and can accurately select various types of ground fault phases. However, under the condition of high transition resistance ground fault, the sensitivity of traditional distance relays is poor and cannot reliably determine the fault inside and outside the zone. Traditional phase selection elements cannot accurately select phases in the case of unknown internal faults; if the highly sensitive zero-sequence reactance line criterion is used to distinguish internal and external faults, the fault phase must be selected first so that the zero-sequence reactance line criterion can be effectively judged. Therefore, how to reliably select phases in the case of unknown internal and external faults under high transition resistance faults is a difficult problem to be solved. Summary of the invention

[0003] In view of the deficiencies in the prior art, the present invention provides a phase selection method based on a novel zero-sequence directional element and a novel zero-sequence current dual-polarization criterion.

[0004] According to one aspect of the present invention, a phase selection method based on a novel zero-sequence directional element and a novel zero-sequence current dual-polarization criterion is provided, comprising:

[0005] Calculate the zero-sequence voltage and zero-sequence current according to the obtained three-phase voltage vector and three-phase current vector at the protection installation point;

[0006] Calculate zero-sequence compensation voltage, grounding compensation voltage and phase-to-phase compensation voltage according to zero-sequence voltage, zero-sequence current and preset high-resistance distance protection setting;

[0007] Determine the fault direction of the protection installation point based on the zero-sequence voltage, zero-sequence current and the preset new zero-sequence directional element criteria;

[0008] In the case where the fault direction is a positive fault, the fault phase is determined according to the three-phase current vector and the preset sequence current absolute value phase selection component criterion;

[0009] The phase selection result is determined according to the fault phase, zero-sequence compensation voltage, grounding compensation voltage, phase-to-phase compensation voltage, and the preset grounding fault criterion based on the amplitude of the sound phase compensation voltage, the zero-sequence current phase selection criterion of the phase compensation voltage polarization, and the zero-sequence current phase selection criterion of the phase-to-phase compensation voltage polarization.

[0010] Optionally, the zero sequence voltage and zero sequence current The calculation formula is:

[0011]

[0012] In the formula, are the three-phase voltage and current phase quantities at the protection installation point respectively. Optionally, the high-resistance distance protection setting Z is preset set The expression is:

[0013] Z set =KZ l

[0014] In the formula, Z1 is the positive sequence impedance of the entire line at this level, and K is the reliability coefficient;

[0015] Zero sequence compensation voltage The calculation formula is:

[0016]

[0017] Optionally, a ground compensation voltage And phase compensation voltage The calculation formula is:

[0018]

[0019] In the formula, k = (z0-z1) / 3z1 is the zero-sequence compensation coefficient of this line, are the voltage and current phasors of each phase, are the phase-to-phase voltage and current phasors respectively, and the superscript ' represents the compensation amount.

[0020] Optionally, the expression of the new zero-sequence directional element criterion is:

[0021]

[0022] In the formula, Z L It is the positive sequence impedance of the whole length of the line at this level; is the zero sequence voltage; is the zero-sequence voltage; k0=(Z0-Z1) / 3Z1 is the zero-sequence compensation coefficient, Z0 and Z1 are the zero-sequence impedance and positive-sequence impedance per unit length of the line respectively. If the new zero-sequence directional element judgment criterion is met, it is regarded as a positive direction fault and enters the phase selection element judgment logic, otherwise it is regarded as a reverse direction fault and the phase selection element and zero-sequence protection are locked.

[0023] Optionally, the expression of the sequence current absolute value phase selection element criterion is:

[0024]

[0025] In the formula, is the positive sequence current phasor based on the current phase, The positive sequence current amplitude is eliminated for the corresponding phase. The maximum phase is confirmed as the fault phase; is the current phasor of each phase.

[0026] Optionally, the phase selection result is determined according to the fault phase, the zero-sequence compensation voltage, the grounding compensation voltage, the phase-to-phase compensation voltage, and a preset grounding fault criterion based on the amplitude of the healthy phase compensation voltage, a zero-sequence current phase selection criterion of the phase compensation voltage polarization, and a zero-sequence current phase selection criterion of the phase-to-phase compensation voltage polarization, including:

[0027] According to the zero-sequence compensation voltage, the grounding compensation voltage and the phase-to-phase compensation voltage, it is judged whether the fault phase meets the grounding fault criterion based on the compensation voltage amplitude of the healthy phase, the zero-sequence current phase selection criterion based on the phase compensation voltage polarization and the zero-sequence current phase selection criterion based on the phase-to-phase compensation voltage polarization;

[0028] When any one of the fault phases A, B or C meets the ground fault criterion based on the healthy phase compensation voltage amplitude, the zero-sequence current phase selection criterion based on the phase compensation voltage polarization, and the zero-sequence current phase selection criterion based on the phase-to-phase compensation voltage polarization, the phase is determined as the phase selection result.

[0029] Optionally, the expression of the ground fault criterion based on the healthy phase compensation voltage amplitude is:

[0030]

[0031] In the formula, is the two-phase compensation voltage between the non-fault phases; m>0.87; U LL is the rated line voltage.

[0032] Optionally, the expression of the zero-sequence current phase selection criterion of the phase compensation voltage polarization is:

[0033]

[0034] in,

[0035]

[0036] In the formula, is the ground compensation voltage; is the zero-sequence current, γ1~γ3 are the action boundary angles of the zero-sequence current phase selection criterion for the phase-to-phase compensation voltage polarization;

[0037] The expression of zero-sequence current phase selection criterion for phase-to-phase compensation voltage polarization is:

[0038]

[0039] In the formula, is the phase compensation voltage.

[0040] According to another aspect of the present invention, a phase selection device based on a novel zero-sequence directional element and a novel zero-sequence current dual-polarization criterion is provided, comprising:

[0041] A first calculation module, used for calculating the zero-sequence voltage and the zero-sequence current according to the acquired three-phase voltage vector and the three-phase current vector at the protection installation point;

[0042] The second calculation module is used to calculate the zero-sequence compensation voltage, the grounding compensation voltage and the phase-to-phase compensation voltage according to the zero-sequence voltage, the zero-sequence current and the preset high-resistance distance protection setting;

[0043] The first determination module is used to determine the fault direction of the protection installation point according to the zero-sequence voltage, the zero-sequence current and the preset new zero-sequence direction element criterion;

[0044] The second determination module is used to determine the fault phase according to the three-phase current vector and the preset sequence current absolute value phase selection component criterion when the fault direction is a positive direction fault;

[0045] The third determination module is used to determine the phase selection result according to the fault phase, zero-sequence compensation voltage, grounding compensation voltage, phase-to-phase compensation voltage, and the preset grounding fault criterion based on the amplitude of the healthy phase compensation voltage, the zero-sequence current phase selection criterion of the phase compensation voltage polarization, and the zero-sequence current phase selection criterion of the phase-to-phase compensation voltage polarization.

[0046] According to another aspect of the present invention, a computer-readable storage medium is provided, wherein the storage medium stores a computer program, and the computer program is used to execute the method described in any one of the above aspects of the present invention.

[0047] According to another aspect of the present invention, an electronic device is provided, comprising: a processor; a memory for storing instructions executable by the processor; the processor is configured to read the executable instructions from the memory and execute the instructions to implement the method described in any one of the above aspects of the present invention.

[0048] Therefore, according to the unique fault characteristics of the fault phase compensation voltage, the sound phase compensation voltage and the zero-sequence current, the present invention proposes a phase selection principle of double polarization of zero-sequence current, which can reliably select the single-phase grounding fault phase in the area when the transition resistance is not greater than 500Ω (500kV), and improve the reliability of the phase selection element in the case of a large transition resistance grounding short circuit fault. This solves the technical problem that the existing sequence current phase selection element is difficult to select the high-resistance grounding fault phase. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] A more complete understanding of exemplary embodiments of the present invention may be obtained by referring to the following drawings:

[0050] Figure 1 It is a flow chart of a phase selection method based on a novel zero-sequence directional element and a novel zero-sequence current dual-polarization criterion provided by an exemplary embodiment of the present invention;

[0051] Figure 2 is a logical diagram of a phase selection algorithm provided by an exemplary embodiment of the present invention;

[0052] Figure 3 is a schematic diagram of a simulation verification power grid platform provided by an exemplary embodiment of the present invention;

[0053] Figure 4 It is a structural schematic diagram of a phase selection device based on a novel zero-sequence directional element and a novel zero-sequence current dual-polarization criterion provided by an exemplary embodiment of the present invention;

[0054] Figure 5 This is a structure of an electronic device provided by an exemplary embodiment of the present invention. DETAILED DESCRIPTION

[0055] Below, the exemplary embodiments according to the present invention will be described in detail with reference to the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments of the present invention, and it should be understood that the present invention is not limited to the exemplary embodiments described here.

[0056] It should be noted that the relative arrangement of components and steps, the numerical expressions and numerical values ​​set forth in these embodiments do not limit the scope of the present invention unless specifically stated otherwise.

[0057] Those skilled in the art can understand that the terms "first" and "second" in the embodiments of the present invention are only used to distinguish different steps, devices or modules, etc., and neither represent any specific technical meaning nor indicate the necessary logical order between them.

[0058] It should also be understood that, in the embodiments of the present invention, “plurality” may refer to two or more than two, and “at least one” may refer to one, two or more than two.

[0059] It should also be understood that any component, data or structure mentioned in the embodiments of the present invention can generally be understood as one or more, unless explicitly limited or otherwise indicated in the context.

[0060] In addition, the term "and / or" in the present invention is only a description of the association relationship of the associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in the present invention generally indicates that the associated objects before and after are in an "or" relationship.

[0061] It should also be understood that the description of the various embodiments of the present invention focuses on the differences between the various embodiments, and the same or similar aspects thereof can be referenced to each other, and for the sake of brevity, they will not be described one by one.

[0062] At the same time, it should be understood that for the convenience of description, the sizes of the various parts shown in the drawings are not drawn according to the actual proportional relationship.

[0063] The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the invention, its application, or uses.

[0064] Technologies, methods, and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the technologies, methods, and equipment should be considered part of the specification.

[0065] It should be noted that like reference numerals and letters refer to similar items in the following figures, and therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0066] Embodiments of the present invention can be applied to electronic devices such as terminal devices, computer systems, servers, etc., which can operate with many other general or special computing system environments or configurations. Examples of well-known terminal devices, computing systems, environments and / or configurations suitable for use with electronic devices such as terminal devices, computer systems, servers, etc. include, but are not limited to: personal computer systems, server computer systems, thin clients, thick clients, handheld or laptop devices, microprocessor-based systems, set-top boxes, programmable consumer electronics, network personal computers, small computer systems, large computer systems, and distributed cloud computing technology environments including any of the above systems, etc.

[0067] Electronic devices such as terminal devices, computer systems, servers, etc. can be described in the general context of computer system executable instructions (such as program modules) executed by computer systems. Generally, program modules can include routines, programs, object programs, components, logic, data structures, etc., which perform specific tasks or implement specific abstract data types. Computer systems / servers can be implemented in a distributed cloud computing environment, where tasks are performed by remote processing devices linked through a communication network. In a distributed cloud computing environment, program modules can be located on local or remote computing system storage media including storage devices.

[0068] Exemplary Methods

[0069] Figure 1 1 is a flow chart of a phase selection method based on a novel zero-sequence directional element and a novel zero-sequence current dual polarization criterion provided by an exemplary embodiment of the present invention. This embodiment can be applied to electronic devices, such as Figure 1 As shown, the phase selection method 100 based on the novel zero-sequence directional element and the novel zero-sequence current dual-polarization criterion includes the following steps:

[0070] Step 101, calculating the zero-sequence voltage and the zero-sequence current according to the acquired three-phase voltage vector and the three-phase current vector at the protection installation point;

[0071] Step 102, calculating the zero-sequence compensation voltage, the grounding compensation voltage and the phase-to-phase compensation voltage according to the zero-sequence voltage, the zero-sequence current and the preset high-resistance distance protection setting;

[0072] Step 103, determining the fault direction of the protection installation point according to the zero-sequence voltage, the zero-sequence current and the preset new zero-sequence directional element criterion;

[0073] Step 104, when the fault direction is a positive fault, determine the fault phase according to the three-phase current vector and a preset sequence current absolute value phase selection component criterion;

[0074] Step 105, determining the phase selection result according to the fault phase, the zero-sequence compensation voltage, the grounding compensation voltage, the phase-to-phase compensation voltage, and the preset grounding fault criterion based on the amplitude of the healthy phase compensation voltage, the zero-sequence current phase selection criterion of the phase compensation voltage polarization, and the zero-sequence current phase selection criterion of the phase-to-phase compensation voltage polarization.

[0075] Specifically, in response to the problem that the existing sequence current phase selection elements are difficult to select the high-resistance grounding fault phase, based on the unique fault characteristics of the fault phase compensation voltage, the sound phase compensation voltage and the zero-sequence current, a zero-sequence current dual polarization phase selection principle is proposed, which can reliably select the single-phase grounding fault phase in the area when the transition resistance is not greater than 500Ω (500kV), thereby improving the reliability of the phase selection element in the event of a large transition resistance grounding short-circuit fault. The present invention proposes a phase selection method based on a new zero-sequence directional element and a new zero-sequence current dual polarization criterion. The specific implementation of the method is as follows:

[0076] (1) Data preparation

[0077] Get the three-phase voltage and current phasors at the protection installation point Calculate zero sequence voltage and zero sequence current

[0078]

[0079] Set the high resistance distance protection setting value:

[0080] Z set =KZ l (1.2)

[0081] Where Z1 is the positive sequence impedance of the entire line at this level, and K is the reliability coefficient, which reflects the scope of protecting the lower-level line.

[0082] Calculate the zero-sequence compensation voltage:

[0083]

[0084] Calculate the ground compensation voltage and phase compensation voltage:

[0085]

[0086] In the formula, k = (z0-z1) / 3z1 is the zero-sequence compensation coefficient of this line, They are the ground compensation voltage and the phase compensation voltage, are the voltage and current phasors of each phase, are the phase-to-phase voltage and current phasors respectively, and the superscript ' represents the compensation amount.

[0087] (2)Reference Figure 2 As shown in the figure, the main criteria include:

[0088] 1) New zero-sequence directional element (criterion 1):

[0089] The new zero-sequence directional element is responsible for determining the fault direction. For a reverse fault, the phase selection element and zero-sequence protection are locked. When the judgment criterion 1 is met, it is regarded as a positive fault and enters the phase selection element judgment logic:

[0090]

[0091] In the formula, Z L It is the positive sequence impedance of the entire length of the line at this level.

[0092] 2) Sequence current absolute value phase selection element (criterion 2):

[0093] The sequence current absolute value phase selection element preliminarily determines the fault phase according to the phase relationship of each sequence current of different types of short-circuit faults, and enters the corresponding phase zero-sequence current dual-polarization phase selection judgment logic.

[0094]

[0095] In the formula, is the positive sequence current phasor based on the current phase, The positive sequence current amplitude is eliminated for the corresponding phase. The maximum phase is confirmed as the fault phase.

[0096] 3) Ground fault judgment criterion based on the amplitude of the healthy phase compensation voltage:

[0097] When the sequence current absolute value phase selection element selects phase A, it may actually be an AN fault, an ABN fault, or a BCN fault. Here, the ABN fault is excluded first. Set the ground fault criterion based on the healthy phase compensation voltage amplitude (criterion 3). If this criterion is met, it is allowed to enter the zero-sequence current dual-polarization phase selection judgment link:

[0098]

[0099] In the formula, m>0.87.

[0100] 4) Zero-sequence current dual-polarization phase selection scheme:

[0101] Design the zero-sequence current phase selection criterion for phase compensation voltage polarization (criterion 4):

[0102]

[0103] Design the zero-sequence current phase selection criterion for phase-to-phase compensation voltage polarization (criterion 5):

[0104]

[0105] In criterion 4, the selection of α and β is determined by the following formula:

[0106]

[0107] When any one of A / B / C is the same and satisfies criteria 3 to 5, it can be confirmed that the phase selection is successful.

[0108] In one embodiment of the present invention, in order to verify the effectiveness of the zero-sequence directional element and phase selection method proposed in this article, Figure 3 Different types of ground short circuit faults inside and outside the simulated area are simulated on the system shown. The simulation system parameters and constants are shown in Table 1. The results of each criterion are recorded as shown in Tables 1 to 3:

[0109] Table 1 Simulation system parameters and constants

[0110]

[0111] Table 2 Identification results of new zero-sequence directional element for forward / reverse direction faults

[0112]

[0113]

[0114] It can be seen from Table 2 that the zero-sequence directional element proposed in this patent has a strong ability to withstand transitions and can accurately distinguish the fault direction under various types of ground short-circuit faults.

[0115] Table 3 Results of various criteria for short-circuit fault at point F2 AN in the zone with different transition resistances

[0116]

[0117] Note: Zero sequence direction "1" represents the positive direction, "2" represents the reverse direction

[0118] Table 4 Results of various criteria for short-circuit fault of ABN at F3 outside the area through different transition resistances

[0119]

[0120] Note: Phase selection result "0" means phase selection failed

[0121] Table 5 Results of various criteria for short-circuit fault of BCN at F3 point outside the area through different transition resistances

[0122]

[0123] Note: Phase selection result "0" means phase selection failed

[0124] It can be seen from Tables 2 to 5 that the proposed ground fault judgment criterion based on the sound phase compensation voltage amplitude and the zero-sequence current dual-polarization phase selection scheme can accurately identify the fault phase of the single-phase ground fault in the zone under the high-resistance fault of 500Ω transition resistance, and reliably distinguish the phase indirect ground fault outside the zone, which improves the selectivity of the existing distance protection in the case of large transition resistance ground short circuit fault.

[0125] Therefore, according to the unique fault characteristics of the fault phase compensation voltage, the sound phase compensation voltage and the zero-sequence current, the present invention proposes a phase selection principle of double polarization of zero-sequence current, which can reliably select the single-phase grounding fault phase in the area when the transition resistance is not greater than 500Ω (500kV), and improve the reliability of the phase selection element in the case of a large transition resistance grounding short circuit fault. This solves the technical problem that the existing sequence current phase selection element is difficult to select the high-resistance grounding fault phase.

[0126] Exemplary Devices

[0127] Figure 4 1 is a schematic diagram of a phase selection device based on a novel zero-sequence directional element and a novel zero-sequence current dual polarization criterion provided by an exemplary embodiment of the present invention. Figure 4 As shown, the device 400 includes:

[0128] A first calculation module 410 is used to calculate the zero-sequence voltage and the zero-sequence current according to the acquired three-phase voltage vector and the three-phase current vector at the protection installation point;

[0129] The second calculation module 420 is used to calculate the zero-sequence compensation voltage, the grounding compensation voltage and the phase-to-phase compensation voltage according to the zero-sequence voltage, the zero-sequence current and the preset high-resistance distance protection setting;

[0130] A first determination module 430 is used to determine the fault direction of the protection installation point according to the zero-sequence voltage, the zero-sequence current and a preset new zero-sequence direction element criterion;

[0131] The second determination module 440 is used to determine the fault phase according to the three-phase current vector and the preset sequence current absolute value phase selection element criterion when the fault direction is a positive direction fault;

[0132] The third determination module 450 is used to determine the phase selection result according to the fault phase, zero-sequence compensation voltage, ground compensation voltage, phase-to-phase compensation voltage, and a preset ground fault criterion based on the amplitude of the healthy phase compensation voltage, a zero-sequence current phase selection criterion of the phase compensation voltage polarization, and a zero-sequence current phase selection criterion of the phase-to-phase compensation voltage polarization.

[0133] Optionally, the zero sequence voltage and zero sequence current The calculation formula is:

[0134]

[0135] In the formula, are the three-phase voltage and current phase quantities at the protection installation point respectively. Optionally, the high-resistance distance protection setting Z is preset set The expression is:

[0136] Zset =KZ l

[0137] In the formula, Z1 is the positive sequence impedance of the entire line at this level, and K is the reliability coefficient;

[0138] Zero sequence compensation voltage The calculation formula is:

[0139]

[0140] Optionally, a ground compensation voltage And phase compensation voltage The calculation formula is:

[0141]

[0142] In the formula, k = (z0-z1) / 3z1 is the zero-sequence compensation coefficient of this line, are the voltage and current phasors of each phase, are the phase-to-phase voltage and current phasors respectively, and the superscript ' represents the compensation amount.

[0143] Optionally, the expression of the new zero-sequence directional element criterion is:

[0144]

[0145] In the formula, Z L It is the positive sequence impedance of the whole length of the line at this level; is the zero sequence voltage; is the zero-sequence voltage; k0=(Z0-Z1) / 3Z1 is the zero-sequence compensation coefficient, Z0 and Z1 are the zero-sequence impedance and positive-sequence impedance per unit length of the line respectively. If the new zero-sequence directional element judgment criterion is met, it is regarded as a positive direction fault and enters the phase selection element judgment logic, otherwise it is regarded as a reverse direction fault and the phase selection element and zero-sequence protection are locked.

[0146] Optionally, the expression of the sequence current absolute value phase selection element criterion is:

[0147]

[0148] In the formula, is the positive sequence current phasor based on the current phase, The positive sequence current amplitude is eliminated for the corresponding phase. The maximum phase is confirmed as the fault phase; is the current phasor of each phase.

[0149] Optionally, the third determining module 450 includes:

[0150] A judgment submodule, used to judge whether the fault phase meets the ground fault criterion based on the amplitude of the sound phase compensation voltage, the zero-sequence current phase selection criterion of the phase compensation voltage polarization, and the zero-sequence current phase selection criterion of the phase compensation voltage polarization according to the zero-sequence compensation voltage, the ground compensation voltage, and the phase-to-phase compensation voltage;

[0151] The determination submodule is used to determine that when any one of the fault phases A, B or C satisfies the ground fault criterion based on the healthy phase compensation voltage amplitude, the zero-sequence current phase selection criterion based on the phase compensation voltage polarization, and the zero-sequence current phase selection criterion based on the phase-to-phase compensation voltage polarization, the phase is determined as the phase selection result.

[0152] Optionally, the expression of the ground fault criterion based on the healthy phase compensation voltage amplitude is:

[0153]

[0154] In the formula, is the two-phase compensation voltage between the non-fault phases; m>0.87; U LL is the rated line voltage.

[0155] Optionally, the expression of the zero-sequence current phase selection criterion of the phase compensation voltage polarization is:

[0156]

[0157] in,

[0158]

[0159] In the formula, is the ground compensation voltage; is the zero-sequence current, γ1~γ3 are the action boundary angles of the zero-sequence current phase selection criterion for the phase-to-phase compensation voltage polarization;

[0160] The expression of zero-sequence current phase selection criterion for phase-to-phase compensation voltage polarization is:

[0161]

[0162] In the formula, is the phase compensation voltage.

[0163] Exemplary Electronic Devices

[0164] Figure 5 This is a structure of an electronic device provided by an exemplary embodiment of the present invention. Figure 5 As shown, the electronic device 50 includes one or more processors 51 and a memory 52 .

[0165] The processor 51 may be a central processing unit (CPU) or other forms of processing units having data processing capabilities and / or instruction execution capabilities, and may control other components in the electronic device to perform desired functions.

[0166] The memory 52 may include one or more computer program products, which may include various forms of computer-readable storage media, such as volatile memory and / or non-volatile memory. The volatile memory may include, for example, random access memory (RAM) and / or cache memory (cache), etc. The non-volatile memory may include, for example, read-only memory (ROM), hard disk, flash memory, etc. One or more computer program instructions may be stored on the computer-readable storage medium, and the processor 51 may run the program instructions to implement the methods of the software programs of the various embodiments of the present invention described above and / or other desired functions. In one example, the electronic device may also include: an input device 53 and an output device 54, which are interconnected via a bus system and / or other forms of connection mechanisms (not shown).

[0167] In addition, the input device 53 may also include, for example, a keyboard, a mouse, etc.

[0168] The output device 54 can output various information to the outside. The output device 54 can include, for example, a display, a speaker, a printer, a communication network and a remote output device connected thereto.

[0169] Of course, to simplify, Figure 5 Only some of the components related to the present invention in the electronic device are shown, and components such as a bus, an input / output interface, etc. are omitted. In addition, the electronic device may further include any other appropriate components according to specific application conditions.

[0170] Exemplary computer program products and computer-readable storage media

[0171] In addition to the above-mentioned methods and devices, an embodiment of the present invention may also be a computer program product, which includes computer program instructions, which, when executed by a processor, enable the processor to execute the steps of the method according to various embodiments of the present invention described in the above-mentioned "Exemplary Method" section of this specification.

[0172] The computer program product may be written in any combination of one or more programming languages ​​to write program code for performing the operations of the embodiments of the present invention, including object-oriented programming languages ​​such as Java, C++, etc., and conventional procedural programming languages ​​such as "C" or similar programming languages. The program code may be executed entirely on the user computing device, partially on the user device, as a separate software package, partially on the user computing device and partially on a remote computing device, or entirely on a remote computing device or server.

[0173] In addition, an embodiment of the present invention may also be a computer-readable storage medium having computer program instructions stored thereon, which, when executed by a processor, enable the processor to execute the steps of the method according to various embodiments of the present invention described in the above “Exemplary Method” section of this specification.

[0174] The computer readable storage medium can adopt any combination of one or more readable media. The readable medium can be a readable signal medium or a readable storage medium. The readable storage medium can include, for example, but is not limited to, a system, system or device of electricity, magnetism, light, electromagnetic, infrared, or semiconductor, or any combination of the above. More specific examples (non-exhaustive list) of readable storage media include: an electrical connection with one or more wires, a portable disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above.

[0175] The basic principle of the present invention is described above in conjunction with specific embodiments. However, it should be pointed out that the advantages, strengths, effects, etc. mentioned in the present invention are only examples and not limitations, and it cannot be considered that these advantages, strengths, effects, etc. must be possessed by each embodiment of the present invention. In addition, the specific details disclosed above are only for the purpose of illustration and facilitation of understanding, rather than limitation, and the above details do not limit the present invention to being implemented by adopting the above specific details.

[0176] Each embodiment in this specification is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the system embodiment, since it basically corresponds to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiment.

[0177] The block diagrams of the devices, systems, equipment, and systems involved in the present invention are only illustrative examples and are not intended to require or imply that they must be connected, arranged, and configured in the manner shown in the block diagram. As will be appreciated by those skilled in the art, these devices, systems, equipment, and systems can be connected, arranged, and configured in any manner. Words such as "including", "comprising", "having", etc. are open words, referring to "including but not limited to", and can be used interchangeably with them. The words "or" and "and" used here refer to the words "and / or" and can be used interchangeably with them, unless the context clearly indicates otherwise. The word "such as" used here refers to the phrase "such as but not limited to", and can be used interchangeably with it.

[0178] The method and system of the present invention may be implemented in many ways. For example, the method and system of the present invention may be implemented by software, hardware, firmware or any combination of software, hardware, firmware. The above order of steps for the method is only for illustration, and the steps of the method of the present invention are not limited to the order specifically described above, unless otherwise specifically stated. In addition, in some embodiments, the present invention may also be implemented as a program recorded in a recording medium, which includes machine-readable instructions for implementing the method according to the present invention. Thus, the present invention also covers a recording medium storing a program for executing the method according to the present invention.

[0179] It should also be noted that in the system, device and method of the present invention, each component or each step can be decomposed and / or recombined. These decompositions and / or recombinations should be regarded as equivalent schemes of the present invention. The above description of the disclosed aspects is provided to enable any technician in the field to make or use the present invention. Various modifications to these aspects are very obvious to those skilled in the art, and the general principles defined here can be applied to other aspects without departing from the scope of the present invention. Therefore, the present invention is not intended to be limited to the aspects shown here, but in accordance with the widest range consistent with the principles and novel features disclosed here.

[0180] The above description has been given for the purpose of illustration and description. In addition, this description is not intended to limit the embodiments of the present invention to the forms disclosed herein. Although a number of example aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, changes, additions and sub-combinations thereof.

Claims

1. A phase selection method based on a novel zero-sequence directional element and a novel zero-sequence current dual-polarization criterion, characterized in that: include: Calculate the zero-sequence voltage and zero-sequence current according to the obtained three-phase voltage vector and three-phase current vector at the protection installation point; Calculate the zero-sequence compensation voltage, the grounding compensation voltage and the phase-to-phase compensation voltage according to the zero-sequence voltage, the zero-sequence current and the preset high-resistance distance protection setting; Determining the fault direction of the protection installation point according to the zero-sequence voltage, the zero-sequence current and a preset new zero-sequence directional element criterion; In the case where the fault direction is a positive direction fault, the fault phase is determined according to the three-phase current vector and a preset sequence current absolute value phase selection element criterion; The phase selection result is determined according to the faulty phase, the zero-sequence compensation voltage, the grounding compensation voltage, the phase-to-phase compensation voltage, and the preset grounding fault criterion based on the amplitude of the healthy phase compensation voltage, the zero-sequence current phase selection criterion of the phase compensation voltage polarization, and the zero-sequence current phase selection criterion of the phase-to-phase compensation voltage polarization.

2. The method according to claim 1, characterized in that The zero sequence voltage and the zero sequence current The calculation formula is: In the formula, They are the three-phase voltage and current phasors at the protection installation point respectively.

3. The method according to claim 2, characterized in that The preset high-resistance distance protection setting Z set The expression is: Z set =KZ l In the formula, Z1 is the positive sequence impedance of the entire line at this level, and K is the reliability coefficient; The zero sequence compensation voltage The calculation formula is:

4. The method according to claim 3, characterized in that The ground compensation voltage And phase compensation voltage The calculation formula is: In the formula, k = (z0-z1) / 3z1 is the zero-sequence compensation coefficient of this line, are the voltage and current phasors of each phase, are the phase-to-phase voltage and current phasors respectively, and the superscript ' represents the compensation amount.

5. The method according to claim 1, characterized in that: The expression of the new zero-sequence directional element criterion is: In the formula, Z L It is the positive sequence impedance of the whole length of the line at this level; is the zero sequence voltage; is the zero-sequence voltage; k0=(Z0-Z1) / 3Z1 is the zero-sequence compensation coefficient, Z0 and Z1 are the zero-sequence impedance and positive-sequence impedance per unit length of the line respectively. If the new zero-sequence directional element criterion is met, it is regarded as a positive direction fault and enters the phase selection element judgment logic; otherwise, it is regarded as a reverse direction fault and the phase selection element and zero-sequence protection are locked.

6. The method according to claim 1, characterized in that The expression of the sequence current absolute value phase selection element criterion is: In the formula, is the positive sequence current phasor based on the current phase, The positive sequence current amplitude is eliminated for the corresponding phase. The maximum phase is confirmed as the fault phase; is the current phasor of each phase.

7. The method according to claim 1, characterized in that Determining a phase selection result according to the fault phase, the zero-sequence compensation voltage, the grounding compensation voltage, the phase-to-phase compensation voltage, a preset grounding fault criterion based on the amplitude of the healthy phase compensation voltage, a zero-sequence current phase selection criterion of the phase compensation voltage polarization, and a zero-sequence current phase selection criterion of the phase-to-phase compensation voltage polarization, including: According to the zero-sequence compensation voltage, the grounding compensation voltage and the phase-to-phase compensation voltage, it is judged whether the fault phase satisfies the grounding fault criterion based on the amplitude of the healthy phase compensation voltage, the zero-sequence current phase selection criterion based on the phase compensation voltage polarization and the zero-sequence current phase selection criterion based on the phase-to-phase compensation voltage polarization; When any one of the fault phases A, B or C satisfies the ground fault criterion based on the healthy phase compensation voltage amplitude, the zero-sequence current phase selection criterion of the phase compensation voltage polarization and the zero-sequence current phase selection criterion of the phase-to-phase compensation voltage polarization, the phase is determined as the phase selection result.

8. The method according to claim 7, characterized in that The expression of the ground fault criterion based on the healthy phase compensation voltage amplitude is: In the formula, is the two-phase compensation voltage between the non-fault phases; m>0.87; U LL is the rated line voltage.

9. The method according to claim 7, characterized in that: The expression of the zero-sequence current phase selection criterion of the phase compensation voltage polarization is: in, In the formula, is the ground compensation voltage; is the zero-sequence current, γ1~γ3 are the action boundary angles of the zero-sequence current phase selection criterion for the phase-to-phase compensation voltage polarization; The expression of the zero-sequence current phase selection criterion of the phase-to-phase compensation voltage polarization is: ΦΦ=BC,CA,AB In the formula, is the phase compensation voltage.

10. A phase selection device based on a novel zero-sequence directional element and a novel zero-sequence current dual-polarization criterion, characterized in that: include: A first calculation module, used for calculating the zero-sequence voltage and the zero-sequence current according to the acquired three-phase voltage vector and the three-phase current vector at the protection installation point; A second calculation module is used to calculate a zero-sequence compensation voltage, a grounding compensation voltage and a phase-to-phase compensation voltage according to the zero-sequence voltage, the zero-sequence current and a preset high-resistance distance protection setting; A first determination module is used to determine the fault direction of the protection installation point according to the zero-sequence voltage, the zero-sequence current and a preset new zero-sequence directional element criterion; A second determination module is used to determine the fault phase according to the three-phase current vector and a preset sequence current absolute value phase selection element criterion when the fault direction is a positive direction fault; The third determination module is used to determine the phase selection result according to the faulty phase, the zero-sequence compensation voltage, the grounding compensation voltage, the phase-to-phase compensation voltage, and the preset grounding fault criterion based on the amplitude of the healthy phase compensation voltage, the zero-sequence current phase selection criterion of the phase compensation voltage polarization, and the zero-sequence current phase selection criterion of the phase-to-phase compensation voltage polarization.

11. A computer-readable storage medium, characterized in that: The storage medium stores a computer program, and the computer program is used to execute the method according to any one of claims 1 to 9.

12. An electronic device, characterized in that: The electronic device comprises: processor; a memory for storing instructions executable by the processor; The processor is used to read the executable instructions from the memory and execute the instructions to implement the method described in any one of claims 1 to 9.

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