A traveling wave impedance protection method and system

Abstract

The present invention proposes a method and system for traveling wave impedance protection, comprising the following steps: Step 1, the traveling wave impedance protection devices on both sides collect the three-phase AC voltage and three-phase AC current at the protection installation in real time; Step 2, the zero-mode component and line-mode component of the voltage and current on both sides are obtained through Karenbel phase-mode transformation; Step 3, the reverse current traveling wave and reverse voltage traveling wave of the zero-mode and line-mode on both sides are calculated; Step 4, the reverse voltage and current traveling waves of each phase for traveling wave impedance are calculated through Karenbel transformation; Step 5, the traveling wave impedance of phase A, phase B, and phase C are calculated respectively; Step 6, the protection is activated after the traveling wave impedance of phase A, phase B, and phase C satisfies the action equation. The traveling wave impedance protection proposed by the present invention can be quickly activated within 10ms, is less affected by the magnitude of the fault current, is less affected by the transition resistance of the fault point, and has clear selectivity for internal and external faults.

Description

Technical Field

[0001] The present invention belongs to the technical field of power systems, and in particular relates to a traveling wave impedance protection method and system. Background Art

[0002] Current differential protection based on Kirchhoff's current law is now widely adopted as the primary protection for transmission lines, essentially meeting the requirements for on-site applications. Longitudinal current differential protection includes phase current differential protection and zero-sequence current differential protection. In the event of a fault with a large transition resistance, zero-sequence current differential protection is the primary mechanism for operation. The operating speed of current phase current differential protection is currently affected by the magnitude of the fault current, while zero-sequence current differential protection typically requires a delay of 60 to 100 milliseconds before operation. For faults with a large transition resistance, the fault clearing time includes the zero-sequence current differential protection's determination time, the protection's delayed operation time, and the circuit breaker tripping time, resulting in a relatively long fault duration.

[0003] When the zero-sequence current differential protection meets its operating conditions, it cannot directly confirm which phase has a fault and needs to select a phase. However, in the case of heavy load and grounding fault with large transition resistance, the zero-sequence current differential protection may fail to select a phase. In the single-phase reclosing mode, if the protection three trips do not reclose during a single-phase fault, it will cause losses.

[0004] Therefore, it is necessary to provide a line protection device with fast action speed and strong phase selection capability. Summary of the Invention

[0005] In order to solve the deficiencies in the prior art, the purpose of the present invention is to provide a method and system for traveling wave impedance protection, which eliminates three-phase electromagnetic coupling through Karenberg transformation, calculates the traveling wave impedance by phase separation of reverse voltage and current fault traveling waves at both ends of the line, and realizes rapid tripping by phase.

[0006] The present invention adopts the following technical solutions.

[0007] In one aspect, the present invention provides a method for traveling wave impedance protection, comprising the following steps:

[0008] Step 1: The traveling wave impedance protection devices on both sides collect the three-phase AC voltage and three-phase AC current at the protection installation in real time;

[0009] Step 2: Based on the data obtained in step 1, the zero-mode component and line-mode component of the voltage and current on both sides are obtained by Karen Bell phase mode transformation;

[0010] Step 3: Calculate the reverse current traveling wave and reverse voltage traveling wave of the zero mode and line mode on both sides based on the data obtained in step 2;

[0011] Step 4, based on the data obtained in step 3, calculate the phase-reversed voltage and current traveling waves used for traveling wave impedance through Karenberg transformation;

[0012] Step 5: Calculate the traveling wave impedance of phase A, phase B, and phase C respectively based on the data obtained in step 4;

[0013] Step 6: The protection is activated after the traveling wave impedance of phases A, B, and C meets the action equation.

[0014] Preferably, in step 1, the traveling wave impedance protection devices on both sides collect the three-phase AC voltage and three-phase AC current at the protection installation in real time, and the three-phase AC voltage collected on the M side is U ma 、U mb 、U mc , the three-phase AC currents collected on the M side are I ma , I mb , I mc , the three-phase AC voltages collected on the N side are U na 、U nb 、U nc , the three-phase AC currents collected on the N side are I na , I nb , I nc .

[0015] Further preferably, in step 1, the traveling wave impedance protection devices on both sides convert the sampled values into vectors through a half-cycle Fourier algorithm, which can be expressed as the following formula:

[0016]

[0017]

[0018]

[0019]

[0020] Where:

[0021] k represents the current moment,

[0022] Indicates the three-phase AC voltage fault component on the M side at the current moment,

[0023] Indicates the three-phase AC current fault component on the M side at the current moment,

[0024] Indicates the fault component of the three-phase AC voltage on the N side at the current moment,

[0025] Indicates the three-phase AC current fault component on the N side at the current moment,

[0026] Indicated as phase A, phase B or phase C,

[0027] represents the M-side phase voltage vector at the current moment,

[0028] represents the M-side phase voltage vector at two wavefront moments,

[0029] represents the M-side phase current vector at the current moment,

[0030] represents the M-side phase current vector at two wavefront moments,

[0031] represents the N-side phase voltage vector at the current moment,

[0032] represents the N-side phase voltage vector at two wave front moments,

[0033] represents the N-side phase current vector at the current moment,

[0034] Represents the N-side phase current vector at two wave-front moments.

[0035] Preferably, in step 2, the calculation of the zero mode component and the line mode component of the voltage and current on both sides is expressed by the following formula:

[0036]

[0037]

[0038]

[0039]

[0040] Where:

[0041] represents the zero-mode voltage on the M side,

[0042] and Indicates the line mode voltage on the M side,

[0043] Indicates the zero-mode current on the M side,

[0044] and Indicates the line mode current on the M side,

[0045] Indicates the N-side zero-mode voltage,

[0046] and Indicates the N-side line mode voltage,

[0047] Indicates the zero-mode current on the N side,

[0048] and Indicates the N-side line mode current,

[0049] Karen Bell phase transformation matrix

[0050] Respectively represent the three-phase voltage fault components on the M side,

[0051] Respectively represent the three-phase current fault components on the M side,

[0052] Represent the three-phase voltage fault components on the N side,

[0053] They represent the three-phase current fault components on the N side respectively.

[0054] Preferably, in step 3, the reverse current traveling waves and reverse voltage traveling waves of the zero mode and line mode on both sides are calculated using the following formula:

[0055]

[0056]

[0057]

[0058]

[0059]

[0060]

[0061] Where:

[0062] represents the reverse zero-mode current traveling wave on the M side,

[0063] represents the reverse zero-mode voltage traveling wave on the M side,

[0064] represents the M-side reverse α-mode current traveling wave,

[0065] represents the reverse α-mode voltage traveling wave on the M side,

[0066] represents the M-side reverse β-mode current traveling wave,

[0067] represents the M-side reverse β-mode voltage traveling wave,

[0068] represents the reverse zero-mode current traveling wave on the N side,

[0069] Represents the N-side reverse zero-mode voltage traveling wave,

[0070] represents the N-side reverse α-mode current traveling wave,

[0071] represents the N-side reverse α-mode voltage traveling wave,

[0072] represents the N-side reverse β-mode current traveling wave,

[0073] represents the N-side reverse β-mode voltage traveling wave,

[0074] They represent the zero mode component, α line mode component, and β line mode component of the reverse voltage traveling wave on the M side, respectively.

[0075] They represent the zero mode component, α line mode component, and β line mode component of the reverse current traveling wave on the M side, respectively.

[0076] They represent the zero mode component, α line mode component, and β line mode component of the N-side reverse voltage traveling wave, respectively.

[0077] They represent the zero mode component, α line mode component, and β line mode component of the N-side reverse current traveling wave, respectively.

[0078] Z c0 Indicates the line zero-mode wave impedance, R0, L0, G0, and C0 represent the zero-sequence resistance, zero-sequence inductance, zero-sequence conductance, and zero-sequence capacitance of each kilometer of the line, respectively.

[0079] Z c1 It represents the line mode wave impedance of the line. R1, L1, G1, and C1 represent the positive sequence resistance, positive sequence inductance, positive sequence conductance, and positive sequence capacitance per kilometer of the line, respectively.

[0080] G0 and G1 are ignored in engineering applications.

[0081] Preferably, in step 4, the reverse voltage and current traveling waves of phase A, phase B, and phase C used in the traveling wave impedance are expressed by the following formula:

[0082]

[0083]

[0084] Where:

[0085] Karen Bell transformation matrix

[0086] They represent the reverse zero-mode current traveling wave, reverse α-mode current traveling wave, and reverse β-mode current traveling wave on the M side, respectively.

[0087] They represent the reverse zero-mode voltage traveling wave, reverse α-mode voltage traveling wave, and reverse β-mode voltage traveling wave on the M side, respectively.

[0088] They represent the reverse zero-mode current traveling wave, reverse α-mode current traveling wave, and reverse β-mode current traveling wave on the N side respectively.

[0089] They represent the reverse zero-mode voltage traveling wave, reverse α-mode voltage traveling wave, and reverse β-mode voltage traveling wave on the N side, respectively.

[0090] l represents the total length of the line,

[0091] γ0 represents the line zero-mode propagation constant, R0, L0, G0, and C0 represent the zero-sequence resistance, zero-sequence inductance, zero-sequence conductance, and zero-sequence capacitance per kilometer of the line, respectively;

[0092] γ1 represents the line mode propagation constant, R1, L1, G1, and C1 represent the positive-sequence resistance, positive-sequence inductance, positive-sequence conductance, and positive-sequence capacitance per kilometer of the line, respectively.

[0093] Preferably, in step 5, the calculation formula of the traveling wave impedance is expressed as follows:

[0094]

[0095] Where:

[0096] is the traveling wave impedance,

[0097] represents the reverse voltage traveling wave,

[0098] Represents a reverse current traveling wave.

[0099] Preferably, the traveling wave impedance The action equation is:

[0100]

[0101] Where:

[0102] K represents the action coefficient,

[0103] If the above conditions are met, it is determined to be an internal fault; otherwise, it is determined to be an external fault.

[0104] The action coefficient K takes a value of 1.2.

[0105] A second aspect of the present invention provides a traveling wave impedance protection system operating a traveling wave impedance protection method, comprising: a data acquisition and preprocessing module, a zero mode component and line mode component calculation module, a zero mode and line mode reverse current traveling wave and reverse voltage traveling wave calculation module, a phase reverse voltage and current traveling wave calculation module for traveling wave impedance, a three-phase traveling wave impedance calculation module, and a traveling wave impedance action equation judgment module, wherein:

[0106] The data acquisition and preprocessing module is used to collect the three-phase AC voltage and three-phase AC current at the protection installation, and calculate the voltage and current fault components respectively, and send them to the zero mode component and line mode component calculation module;

[0107] The zero mode component and line mode component calculation module is used to calculate the zero mode component and line mode component of the voltage and current on both sides, and send them to the zero mode and line mode reverse current traveling wave and reverse voltage traveling wave calculation module;

[0108] The reverse current traveling wave and reverse voltage traveling wave calculation module of the zero mode and line mode is used to calculate the reverse current traveling wave and reverse voltage traveling wave of the zero mode and line mode on both sides, and send them to the reverse voltage and current traveling wave calculation module of each phase for wave impedance;

[0109] The module for calculating the traveling wave impedance's respective reverse voltages and currents is used to calculate the traveling wave impedance's respective reverse voltages and currents.

[0110] The three-phase traveling wave impedance calculation module is used to calculate the traveling wave impedance of phase A, phase B, and phase C, and send it to the traveling wave impedance action equation judgment module;

[0111] The traveling wave impedance action equation judgment module is used to identify faults within and outside the zone, and the traveling wave impedance protection can achieve phase tripping.

[0112] The beneficial effect of the present invention is that, compared with the prior art, the traveling wave impedance protection of the present invention can act quickly within 10ms, is less affected by the magnitude of the fault current, is less affected by the transition resistance of the fault point, can reliably select phases in the event of a grounding fault through a large transition resistance, and effectively identify faults within and outside the zone. BRIEF DESCRIPTION OF THE DRAWINGS

[0113] Figure 1 Schematic diagram of configuring traveling wave impedance protection on both sides of the line.

[0114] Figure 2 The figure is a flow chart of a traveling wave impedance protection method. DETAILED DESCRIPTION

[0115] The present application will be further described below in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present application.

[0116] Figure 1 Schematic diagram of traveling wave impedance protection configured on both sides of a line. In the diagram, the traveling wave impedance protection device collects three-phase AC voltages from the potential transformer (PT) and current transformer (CT) at the protection installation location in real time, tripping circuit breaker B when the protection is activated. The traveling wave impedance protection devices on both sides of the line are connected via a fiber optic channel, enabling synchronous sampling and real-time transmission and reception of three-phase voltage and current data. The positive direction of the traveling wave is shown in the diagram.

[0117] The total length of the MN line is l, the current side is the M side, and the opposite side is the N side. Points F and K are the fault points inside and outside the line area, respectively.

[0118] like Figure 2 As shown, embodiment 1 of the present invention provides a traveling wave impedance protection method, comprising the following steps:

[0119] Step 1: The traveling wave impedance protection devices on both sides collect the three-phase AC voltage and three-phase AC current at the protection installation in real time.

[0120] The three-phase AC voltages collected on the M side are U ma 、U mb 、U mc , the three-phase AC currents collected on the M side are I ma , I mb , I mc , the three-phase AC voltages collected on the N side are U na 、U nb 、U nc , the three-phase AC currents collected on the N side are I na , I nb , Inc .

[0121] The traveling wave impedance protection devices on both sides convert the sampling values into vectors through the half-cycle Fourier algorithm.

[0122] Three-phase AC voltage fault component on the M side Three-phase AC current fault component on side M N-side three-phase AC voltage fault component N-side three-phase AC current fault component The calculation formulas at time k are:

[0123]

[0124]

[0125]

[0126]

[0127] Where:

[0128] Respectively represent phase A, phase B or phase C,

[0129] k represents the current moment,

[0130] represents the phase voltage vector of side M at the current moment,

[0131] represents the M-side phase voltage vector at two wavefront moments,

[0132] represents the M-side phase current vector at the current moment,

[0133] represents the M-side phase current vector at two wavefront moments,

[0134] represents the N-side phase voltage vector at the current moment,

[0135] represents the N-side phase voltage vector at two wave front moments,

[0136] represents the N-side phase current vector at the current moment,

[0137] Represents the N-side phase current vector at two wave-front moments.

[0138] Step 2: After Karen Bell phase mode transformation, the zero mode component and line mode component of the voltage and current on both sides are obtained.

[0139] In order to eliminate three-phase electromagnetic coupling, the three-phase AC voltage mutation and the three-phase AC current mutation need to be transformed by Karen Bell phase mode to obtain the zero mode component and the α and β line mode components.

[0140] M-side zero mode voltage and line mode voltage and M-side zero mode current and line mode current and N-side zero mode voltage and line mode voltage and N-side zero mode current and line mode current and The calculation formulas are:

[0141]

[0142]

[0143]

[0144]

[0145] Where:

[0146] Karen Bell phase transformation matrix

[0147] are the three-phase voltage fault components on the M side,

[0148] are the three-phase current fault components on the M side,

[0149] are the three-phase voltage fault components on the N side,

[0150] They are the three-phase current fault components on the N side respectively.

[0151] Step 3: Calculate the reverse current traveling wave and reverse voltage traveling wave of the zero mode and line mode on both sides.

[0152] Reverse zero-mode current traveling wave on the M side Reverse zero-mode voltage traveling wave Reverse α-mode current traveling wave Reverse α-mode voltage traveling wave Reverse β-mode current traveling wave Reverse β-mode voltage traveling wave And the reverse zero-mode current traveling wave on the N side Reverse zero-mode voltage traveling wave Reverse α-mode current traveling wave Reverse α-mode voltage traveling wave Reverse β-mode current traveling wave Reverse β-mode voltage traveling wave They are:

[0153]

[0154]

[0155]

[0156]

[0157]

[0158]

[0159] Where:

[0160] They represent the zero mode component, α line mode component, and β line mode component of the reverse voltage traveling wave on the M side, respectively.

[0161] They represent the zero mode component, α line mode component, and β line mode component of the reverse current traveling wave on the M side, respectively.

[0162] They represent the zero mode component, α line mode component, and β line mode component of the N-side reverse voltage traveling wave, respectively.

[0163] They represent the zero mode component, α line mode component, and β line mode component of the N-side reverse current traveling wave, respectively.

[0164] Z c0 Indicates the line zero-mode wave impedance, R0, L0, G0, and C0 represent the zero-sequence resistance, zero-sequence inductance, zero-sequence conductance, and zero-sequence capacitance of each kilometer of the line, respectively.

[0165] Z c1 It represents the line mode wave impedance of the line. R1, L1, G1, and C1 represent the positive sequence resistance, positive sequence inductance, positive sequence conductance, and positive sequence capacitance per kilometer of the line, respectively.

[0166] G0 and G1 can be ignored in engineering applications.

[0167] Step 4: Calculate the reverse voltage and current traveling waves for traveling wave impedance through Karenbel transformation.

[0168] Through Karen Bell transformation, the reverse voltage and current traveling waves of phase A, phase B, and phase C used to calculate the traveling wave impedance are:

[0169]

[0170]

[0171] Where:

[0172] Karen Bell transformation matrix

[0173] They represent the reverse zero-mode current traveling wave, reverse α-mode current traveling wave, and reverse β-mode current traveling wave on the M side, respectively.

[0174] They represent the reverse zero-mode voltage traveling wave, reverse α-mode voltage traveling wave, and reverse β-mode voltage traveling wave on the M side, respectively.

[0175] They represent the reverse zero-mode current traveling wave, reverse α-mode current traveling wave, and reverse β-mode current traveling wave on the side, respectively.

[0176] They represent the reverse zero-mode voltage traveling wave, reverse α-mode voltage traveling wave, and reverse β-mode voltage traveling wave on the N side, respectively.

[0177] l represents the total length of the line,

[0178] γ0 represents the line zero-mode propagation constant, R0, L0, G0, and C0 represent the zero-sequence resistance, zero-sequence inductance, zero-sequence conductance, and zero-sequence capacitance per kilometer of the line, respectively;

[0179] γ1 represents the line mode propagation constant, R1, L1, G1, and C1 represent the positive sequence resistance, positive sequence inductance, positive sequence conductance, and positive sequence capacitance per kilometer of the line, respectively.

[0180] G0 and G1 can be ignored in engineering applications.

[0181] Step 5: Calculate the traveling wave impedance of phase A, phase B, and phase C respectively.

[0182] Traveling wave impedance The calculation formula is:

[0183]

[0184] Where:

[0185] Indicates phase A, phase B or phase C,

[0186] Z c0Indicates the line zero-mode wave impedance,

[0187] Z c1 It represents the line mode wave impedance of the line.

[0188] γ0 represents the line zero-mode propagation constant,

[0189] l represents the total length of the line,

[0190] represents the reverse voltage traveling wave,

[0191] represents the reverse current traveling wave,

[0192] represents the reverse zero-mode current traveling wave on the M side,

[0193] Represents the reverse zero-mode current traveling wave on the N side.

[0194] Step 6: The protection is activated after the traveling wave impedance of phases A, B, and C meets the action equation.

[0195] Traveling wave impedance The action equation is:

[0196]

[0197] Where:

[0198] Indicates phase A, phase B or phase C,

[0199] Z c1 It represents the line mode wave impedance of the line.

[0200] K represents the action coefficient.

[0201] In this embodiment, preferably, the action coefficient K is selected as 1.2.

[0202] Out-of-area faults, Approaching 0, If it is very large, it will not meet the action conditions;

[0203] Faults within the area, The operating conditions are met. Therefore, the traveling wave impedance protection can reliably identify faults within and outside the zone and has clear selectivity.

[0204] According to the traveling wave impedance discrimination results of phase A, phase B and phase C, the traveling wave impedance protection can achieve phase tripping.

[0205] The traveling wave impedance protection simultaneously calculates the impedance of phases A, B, and C, and is less affected by transition resistance. When any phase meets the action conditions, the protection can act quickly and has a phase selection function.

[0206] Embodiment 2 of the present invention provides a traveling wave impedance protection system operating a traveling wave impedance protection method, comprising: a data acquisition and preprocessing module, a zero mode component and line mode component calculation module, a zero mode and line mode reverse current traveling wave and reverse voltage traveling wave calculation module, a phase reverse voltage and current traveling wave calculation module for traveling wave impedance, a three-phase traveling wave impedance calculation module, and a traveling wave impedance action equation judgment module, wherein:

[0207] The data acquisition and preprocessing module is used to collect the three-phase AC voltage and three-phase AC current at the protection installation, calculate the voltage and current fault components respectively, and send them to the zero-mode component and line-mode component calculation modules;

[0208] The zero mode component and line mode component calculation module is used to calculate the zero mode component and line mode component of the voltage and current on both sides, and send them to the zero mode and line mode reverse current traveling wave and reverse voltage traveling wave calculation module;

[0209] The reverse current traveling wave and reverse voltage traveling wave calculation module of zero mode and line mode is used to calculate the reverse current traveling wave and reverse voltage traveling wave of zero mode and line mode on both sides, and send them to the reverse voltage and current traveling wave calculation module of each phase for wave impedance;

[0210] The phase-to-phase reverse voltage and current traveling wave calculation module for traveling wave impedance is used to calculate the phase-to-phase reverse voltage and current traveling waves for traveling wave impedance;

[0211] The three-phase traveling wave impedance calculation module is used to calculate the traveling wave impedance of phase A, phase B, and phase C, and send it to the traveling wave impedance action equation judgment module;

[0212] The traveling wave impedance action equation judgment module is used to identify faults within and outside the zone, and the traveling wave impedance protection can achieve phase tripping.

[0213] The beneficial effect of the present invention is that, compared with the prior art, the traveling wave impedance protection of the present invention can act quickly within 10ms, is less affected by the magnitude of the fault current, is less affected by the transition resistance of the fault point, can reliably select phases in the event of a grounding fault through a large transition resistance, and effectively identify faults within and outside the zone.

[0214] The applicant of the present invention has made a detailed explanation and description of the implementation examples of the present invention in conjunction with the drawings in the specification. However, those skilled in the art should understand that the above implementation examples are only preferred implementation plans of the present invention, and the detailed description is only to help readers better understand the spirit of the present invention, and is not a limitation on the scope of protection of the present invention. On the contrary, any improvements or modifications based on the inventive spirit of the present invention should fall within the scope of protection of the present invention.

Claims

1. A traveling wave impedance protection method, characterized in that: The following steps are involved: Step 1: The traveling wave impedance protection devices on both sides of the line collect the three-phase AC voltage and three-phase AC current at the protection installation in real time; Step 2: Based on the data obtained in step 1, the zero-mode component and line-mode component of the voltage and current on both sides are obtained by Karen Bell phase mode transformation; Step 3: Calculate the reverse current traveling wave and reverse voltage traveling wave of the zero mode and line mode on both sides based on the data obtained in step 2; Step 4, based on the data obtained in step 3, calculate the phase-reversed voltage and current traveling waves used for traveling wave impedance through Karenberg transformation; Step 5: Calculate the traveling wave impedance of phase A, phase B, and phase C respectively based on the data obtained in step 4; the calculation formula of the traveling wave impedance is expressed as follows: Where: represents the traveling wave impedance, where Indicates phase A, phase B or phase C; represents a reverse voltage traveling wave; represents a reverse current traveling wave; Indicates the line zero-mode wave impedance; Indicates the line mode wave impedance of the line; represents the reverse zero-mode current traveling wave on the M side; Represents the reverse zero-mode current traveling wave on the N side; represents the line zero-mode propagation constant; Indicates the total length of the line; Step 6: The protection action is performed after the traveling wave impedance of phase A, phase B, and phase C meets the action equation. The action equation is: Where: represents the action coefficient, If the above conditions are met, it is determined to be an internal fault; otherwise, it is determined to be an external fault.

2. The traveling wave impedance protection method according to claim 1, characterized in that: In step 1, the traveling wave impedance protection devices on both sides collect the three-phase AC voltage and three-phase AC current at the protection installation in real time. The three-phase AC voltage collected on the M side is 、 、 , the three-phase AC currents collected on the M side are 、 、 , the three-phase AC voltages collected on the N side are 、 、 , the three-phase AC currents collected on the N side are 、 、 .

3. The traveling wave impedance protection method according to claim 2, characterized in that: In step 1, the traveling wave impedance protection devices on both sides use the half-cycle Fourier algorithm to convert the sampled values into vectors, which can be expressed as the following formula: Where: Indicates the current moment, Indicates the three-phase AC voltage fault component on the M side at the current moment, Indicates the three-phase AC current fault component on the M side at the current moment, Indicates the fault component of the three-phase AC voltage on the N side at the current moment, Indicates the three-phase AC current fault component on the N side at the current moment, Indicated as phase A, phase B or phase C, represents the M-side phase voltage vector at the current moment, represents the M-side phase voltage vector at two wavefront moments, represents the M-side phase current vector at the current moment, represents the M-side phase current vector at two wavefront moments, represents the N-side phase voltage vector at the current moment, represents the N-side phase voltage vector at two wave front moments, represents the N-side phase current vector at the current moment, Represents the N-side phase current vector at two wave-front moments.

4. The traveling wave impedance protection method according to claim 3, characterized in that: In step 2, the calculation of the zero mode component and line mode component of the voltage and current on both sides is expressed by the following formula: Where: represents the zero-mode voltage on the M side, and Indicates the line mode voltage on the M side, Indicates the zero-mode current on the M side, and Indicates the line mode current on the M side, Indicates the N-side zero-mode voltage, and Indicates the N-side line mode voltage, Indicates the zero-mode current on the N side, and Indicates the N-side line mode current, Karen Bell phase transformation matrix , 、 、 Respectively represent the three-phase voltage fault components on the M side, 、 、 Respectively represent the three-phase current fault components on the M side, 、 、 Represent the three-phase voltage fault components on the N side, 、 、 They represent the three-phase current fault components on the N side respectively.

5. The traveling wave impedance protection method according to claim 4, characterized in that: In step 3, the reverse current traveling waves and reverse voltage traveling waves of the zero mode and line mode on both sides are calculated using the following formula: ， ， ， ， ， ， Where: represents the reverse zero-mode current traveling wave on the M side, represents the reverse zero-mode voltage traveling wave on the M side, Indicates M side reverse Mode current traveling wave, Indicates M side reverse Mode voltage traveling wave, Indicates M side reverse Mode current traveling wave, Indicates M side reverse Mode voltage traveling wave, represents the reverse zero-mode current traveling wave on the N side, Represents the N-side reverse zero-mode voltage traveling wave, Indicates N-side reverse Mode current traveling wave, Indicates N-side reverse Mode voltage traveling wave, Indicates N-side reverse Mode current traveling wave, Indicates N-side reverse Mode voltage traveling wave, 、 、 They represent the zero mode component of the reverse voltage traveling wave on the M side, Line mode component, Line mode component, 、 、 They represent the zero mode component of the reverse current traveling wave on the M side, Line mode component, Line mode component, 、 、 They represent the zero mode component of the N-side reverse voltage traveling wave, Line mode component, Line mode component, 、 、 They represent the zero mode component of the N-side reverse current traveling wave, Line mode component, Line mode component, Indicates the line zero-mode wave impedance, , 、 、 、 Respectively represent the zero-sequence resistance, zero-sequence inductance, zero-sequence conductance, and zero-sequence capacitance per kilometer of the line. It represents the line mode wave impedance of the line. , 、 、 、 Respectively represent the positive sequence resistance, positive sequence inductance, positive sequence conductance and positive sequence capacitance per kilometer of the line. and Ignored in engineering applications.

6. The traveling wave impedance protection method according to claim 5, characterized in that: In step 4, the reverse voltage and current traveling waves of phases A, B, and C used in the traveling wave impedance are expressed by the following formula: Where: Karen Bell transformation matrix , 、 、 Respectively represent the reverse zero-mode current traveling wave on the M side, the reverse Mode current traveling wave, reverse Mode current traveling wave, 、 、 Represents the reverse zero-mode voltage traveling wave on the M side, the reverse Mode voltage traveling wave, reverse Mode voltage traveling wave, 、 、 Represents the reverse zero-mode current traveling wave on the N side, the reverse Mode current traveling wave, reverse Mode current traveling wave, 、 、 Represents the reverse zero-mode voltage traveling wave on the N side, the reverse Mode voltage traveling wave, reverse Mode voltage traveling wave, Indicates the total length of the line. represents the line zero-mode propagation constant, , 、 、 、 Respectively represent the zero-sequence resistance, zero-sequence inductance, zero-sequence conductance, and zero-sequence capacitance per kilometer of the line; represents the line mode propagation constant, , 、 、 They represent the positive-sequence resistance, positive-sequence inductance, positive-sequence conductance, and positive-sequence capacitance per kilometer of the line respectively.

7. The traveling wave impedance protection method according to claim 6, characterized in that: In step 6, the action coefficient The value is 1.

2.

8. A system for operating a traveling wave impedance protection system according to a traveling wave impedance protection method according to any one of claims 1 to 7, comprising: The data acquisition and preprocessing module, the zero mode component and line mode component calculation module, the zero mode and line mode reverse current traveling wave and reverse voltage traveling wave calculation module, the phase reverse voltage and current traveling wave calculation module for traveling wave impedance, the three-phase traveling wave impedance calculation module and the traveling wave impedance action equation judgment module are characterized by: The data acquisition and preprocessing module is used to collect the three-phase AC voltage and three-phase AC current at the protection installation, and calculate the voltage and current fault components respectively, and send them to the zero mode component and line mode component calculation module; The zero mode component and line mode component calculation module is used to calculate the zero mode component and line mode component of the voltage and current on both sides, and send them to the zero mode and line mode reverse current traveling wave and reverse voltage traveling wave calculation module; The reverse current traveling wave and reverse voltage traveling wave calculation module of the zero mode and line mode is used to calculate the reverse current traveling wave and reverse voltage traveling wave of the zero mode and line mode on both sides, and send them to the reverse voltage and current traveling wave calculation module of each phase for wave impedance; The module for calculating the traveling wave impedance's respective reverse voltages and currents is used to calculate the traveling wave impedance's respective reverse voltages and currents. The three-phase traveling wave impedance calculation module is used to calculate the traveling wave impedance of phase A, phase B, and phase C, and send it to the traveling wave impedance action equation judgment module; The traveling wave impedance action equation judgment module is used to identify faults within and outside the zone, and the traveling wave impedance protection can achieve phase tripping.

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