A method, device and computer program product for determining the nature of an interphase fault

Abstract

This invention discloses a method, apparatus, and computer program product for determining the nature of phase-to-phase faults. The method includes: acquiring a fault recording file of a power system; extracting three-phase voltage and current data from the fault recording file; determining whether a phase-to-phase fault has occurred based on the three-phase voltage and current data; if a phase-to-phase fault is determined, identifying the faulty and non-faulty phases; determining the fault direction (positive or negative) of the phase-to-phase fault based on the phase relationship between the current of the faulty phase and the voltage of the non-faulty phase; determining the fault nature (metallic or fault via a transition resistor) of the phase-to-phase fault based on the phase relationship between the current of the faulty phase and the voltage of the non-faulty phase, and the voltage amplitude relationship of the faulty phases; and determining the fault location of the phase-to-phase fault based on the voltage phase relationship of the faulty phases. This invention significantly improves the accuracy and reliability of phase-to-phase fault diagnosis.

Description

Technical Field

[0001] This invention relates to the field of power system technology, specifically to a method, device, and computer program product for determining the nature of phase-to-phase faults. Background Technology

[0002] During power system operation, various types of faults occur, primarily including single-phase grounding faults, phase-to-phase short-circuit faults, two-phase grounding faults, three-phase short-circuit faults, and open-circuit faults. When a fault occurs, relay protection professionals rely on fault recorders to record transient current and voltage waveform data. By analyzing fault reports, they diagnose the detailed characteristics of the fault, including fault type (e.g., single-phase grounding, phase-to-phase short circuit), fault nature (whether it involves a transition resistance or is a metallic fault), fault location (the beginning, middle, or end of the transmission line), and fault direction (forward or reverse). Among these, the transition resistance characteristic (reflecting the resistance value at the fault point) is a key parameter for distinguishing the severity of the fault, while the fault location and direction directly affect the operating logic and selectivity of the protection device.

[0003] However, in existing technologies, professional fault analysis is generally limited to the preliminary identification of fault categories (such as distinguishing between single-phase grounding and phase-to-phase faults), failing to systematically analyze the transition resistance characteristics, precise spatial location, and directionality of the fault. For example, existing analysis methods are usually based only on a rough comparison of waveform amplitude and phase, lacking quantitative calculation of transition resistance (such as extraction through impedance tracing or fault components), and do not combine line parameters to achieve high-precision fault location (such as using traveling wave ranging or impedance methods). This lack of analytical depth makes it impossible to accurately assess the essential characteristics of the fault (such as the impact of transition resistance on fault current), thus restricting the optimization of relay protection strategies, reducing the reliability and rapid response capability of system fault diagnosis, and making it difficult to meet the needs of modern smart grids for accurate fault diagnosis and self-healing control. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a method, device and computer program product for judging the nature of phase-to-phase faults, so as to realize the accurate judgment of phase-to-phase faults in power systems and improve the reliability and rapid response capability of power system fault diagnosis.

[0005] To solve the above-mentioned technical problems, the present invention provides a method for determining the nature of phase-to-phase faults, comprising: Step S1: Obtain the fault recording file of the power system and extract the three-phase voltage data and three-phase current data from the fault recording file; Step S2: Based on the three-phase voltage data and three-phase current data, determine whether a phase-to-phase fault has occurred. If a phase-to-phase fault is determined, identify the faulty phase and the non-faulty phase. Step S3: Based on the phase relationship between the current of the two faulty phases and the voltage of the non-faulty phases, determine whether the fault direction of the interphase fault is a positive or negative fault. Step S4: Based on the phase relationship between the current of the two faulty phases and the voltage of the non-faulty phases, and the voltage amplitude relationship between the two faulty phases, determine whether the fault nature of the interphase fault is a metallic fault or a fault through a transition resistor. Step S5: Determine the fault location of the interphase fault based on the voltage phase relationship between the two faulty phases.

[0006] Preferably, in step S2, a phase-to-phase fault is determined to have occurred when all of the following conditions are met: Two of the three-phase voltages have reduced amplitude, while the voltage amplitude and phase of the remaining phase do not change significantly, and there is no zero-sequence voltage. The amplitudes of the two phase currents corresponding to the voltage drop increase synchronously at the moment of voltage drop, there is no zero-sequence current, and the amplitudes of the two phases with increasing current are equal but opposite in phase; At the same time, the two phases with decreased voltage and increased current are identified as faulty phases, and the remaining phase is identified as a non-faulty phase.

[0007] Preferably, in step S3, the phase-to-phase fault is determined to be a positive-direction fault when any of the following conditions are met: In a two-phase fault phase current, the lagging phase current leads the non-fault phase voltage by 10°~90°. In a two-phase fault current, the leading phase current lags the non-fault phase voltage by 90°~170°.

[0008] Preferably, in step S4, the phase-to-phase fault is determined to be a fault via the transition resistor when any of the following conditions are met: The angle by which the lagging phase current in the two-phase fault current leads the non-fault phase voltage is greater than 10° and less than 90°. The leading phase current in the two-phase fault current lags the non-fault phase voltage by an angle greater than 90° and less than 170°. The voltage amplitudes of the two faulty phases are not equal, and the voltage amplitude of the leading phase is greater than that of the lagging phase.

[0009] Preferably, in step S4, the interphase fault is determined to be a metallic fault when any of the following conditions are met: The angle by which the lagging phase current in the two-phase fault current leads the non-faulty phase voltage is 10°. The leading phase current in the two-phase fault current lags the non-fault phase voltage by an angle of 170°. The voltage amplitudes of the two faulty phases are equal, and the voltages of the two faulty phases are symmetrical about the voltages of the non-faulty phases.

[0010] Preferably, in step S5, when the voltages of the two faulty phases are in phase and opposite to the voltages of the non-faulty phases, the phase-to-phase fault is determined to be a fault at the line outlet; the phase difference between the voltages of the two faulty phases is smaller than the phase difference during normal operation, and the farther the distance between the fault point and the measurement point, the greater the phase difference between the voltages of the two faulty phases.

[0011] Preferably, in step S5, the cosine value of the voltage phase difference between the two faulty phases is calculated using the following formula:

[0012] in, This represents the phase difference between the voltages of the two faulty phases, namely phase A and phase B. , These are the phase voltage amplitudes of phase A and phase B, respectively. This represents the line voltage amplitude between phase A and phase B.

[0013] Preferably, in step S5, the fault distance between the fault point and the measurement point is calculated using the following formula. : =

[0014] in, This represents the impedance per unit length of the transmission line. This refers to the amplitude of the line current between phases A and B. This represents the phase current amplitude of the faulty phase A.

[0015] The present invention also provides a device for determining the nature of phase-to-phase faults, comprising: One or more processors; Memory; One or more applications, wherein the one or more applications are stored in the memory and configured to be executed by the one or more processors, and the one or more applications are configured to perform the phase-to-phase fault nature determination method.

[0016] The present invention also provides a computer program product, including computer instructions, which instruct a computer device to perform operations corresponding to the phase-to-phase fault nature determination method.

[0017] The beneficial effects of this invention are as follows: Based on power system fault recording files, this invention sequentially completes the accurate determination of phase-to-phase faults, identification of fault direction (forward and reverse), differentiation of fault nature (metallic and through-transition resistance), and qualitative and quantitative calculation of fault location. This overcomes the limitations of existing technologies that can only preliminarily identify phase-to-phase fault categories, achieving a systematic and comprehensive analysis of the core characteristics of phase-to-phase faults. This invention relies on multi-dimensional feature cross-validation of voltage, current, and zero-sequence components to form judgment rules, combined with dedicated formulas to quantitatively calculate fault distance. This avoids the problem of misjudgment caused by single-feature judgment, and achieves accurate identification of fault features and quantitative location of faults, significantly improving the accuracy and reliability of phase-to-phase fault diagnosis. Simultaneously, this invention provides relay protection professionals with comprehensive and accurate fault feature data, effectively supporting the optimization of relay protection strategies, enhancing the rapid response capability of power system fault diagnosis, meeting the actual needs of modern smart grids for accurate fault diagnosis and self-healing control, and ensuring the safe and stable operation of the power system. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a flowchart illustrating a method for determining the nature of phase-to-phase faults according to an embodiment of the present invention. Detailed Implementation

[0020] The following description of the embodiments is taken with reference to the accompanying drawings, which illustrate specific embodiments in which the invention can be implemented.

[0021] Please refer to Figure 1 As shown, an embodiment of the present invention provides a method for determining the nature of phase-to-phase faults, including: Step S1: Obtain the fault recording file of the power system and extract the three-phase voltage data and three-phase current data from the fault recording file; Step S2: Based on the three-phase voltage data and three-phase current data, determine whether a phase-to-phase fault has occurred. If a phase-to-phase fault is determined, identify the faulty phase and the non-faulty phase. Step S3: Based on the phase relationship between the current of the two faulty phases and the voltage of the non-faulty phases, determine whether the fault direction of the interphase fault is a positive or negative fault. Step S4: Based on the phase relationship between the current of the two faulty phases and the voltage of the non-faulty phases, and the voltage amplitude relationship between the two faulty phases, determine whether the fault nature of the interphase fault is a metallic fault or a fault through a transition resistor. Step S5: Determine the fault location of the interphase fault based on the voltage phase relationship between the two faulty phases.

[0022] Specifically, this embodiment of the invention takes a phase-to-phase fault occurring in phases A and B of a power system as an example to illustrate the phase-to-phase fault nature judgment method described in this invention. For two-phase phase-to-phase faults in phases A and C or phases B and C of a power system, the judgment steps and judgment conditions of this embodiment can be followed. The phase-to-phase fault nature judgment method of this invention is based on the fault recording file generated by the power system fault recorder. By extracting the electrical quantity data in the fault recording file, the phase-to-phase fault judgment, fault direction judgment, fault nature judgment, and fault location determination are completed sequentially, ultimately realizing a systematic and accurate analysis of phase-to-phase faults in the power system.

[0023] Step S1 in this embodiment of the invention is used to acquire fault recording files and extract electrical quantity data. Specifically, it involves acquiring power system fault recording files and extracting the three-phase phase voltages (phase A voltages) during the fault occurrence period from the fault recording files. Phase B voltage C-phase voltage Three-phase current (phase A current) Phase B current C-phase current The amplitude and phase information of the zero-sequence voltage and zero-sequence current are extracted, and the corresponding numerical information is also extracted, providing a data basis for the judgment of subsequent steps.

[0024] Step S2 involves determining phase-to-phase faults and identifying the faulty and non-faulty phases. Based on the extracted electrical quantity data, it is determined whether a phase-to-phase fault has occurred in the power system. A phase-to-phase fault is determined when all of the following conditions are met simultaneously, and the faulty and non-faulty phases are identified concurrently: (1) The voltage amplitudes of phase A and phase B in the three-phase voltage decreased significantly, while the voltage amplitude and phase of phase C remained almost unchanged, and no zero-sequence voltage appeared in the power system. (2) The currents of phase A and phase B corresponding to the voltage drop of phase A and phase B increase synchronously at the same time when the voltage of phase A and phase B decreases. No zero-sequence current appears in the power system, and the currents of phase A and phase B with increased amplitude have equal amplitude and opposite phase. When the above conditions are met, phases A and B, where the voltage amplitude decreases and the current amplitude increases, are identified as faulty phases, while phase C, where the voltage and current show no obvious abnormalities, is identified as a non-faulty phase.

[0025] Step S3 determines the fault direction of the interphase fault. Based on the phase relationship between the faulty phase current and the non-faulty phase voltage, the fault direction of the interphase fault is determined to be either a forward fault or a reverse fault. The interphase fault is determined to be a forward fault if any of the following conditions are met; otherwise, it is determined to be a reverse fault: (1) The lagging phase current, i.e., phase B current, in the two fault phase currents leads the non-fault phase current, i.e., phase C voltage, by 10°~90°; (2) The current of the leading phase in the two fault phases is the current of phase A, and the voltage of the lagging phase is the voltage of phase C, which is 90°~170° behind the current of the non-fault phase.

[0026] Step S4 determines the nature of the interphase fault. Based on the phase relationship between the fault phase current and the non-fault phase voltage, and the amplitude relationship between the two fault phase voltages, the nature of the interphase fault is determined to be either a fault through a transition resistor or a metallic fault. The specific determination rules are as follows: (a) Determination of faults via transition resistor The phase-to-phase fault is determined to be a fault via the transition resistor if any of the following conditions are met: (1) The lagging phase current, i.e., phase B current, in the two fault phase currents leads the non-fault phase current, i.e., phase C voltage, by an angle greater than 10° and less than 90°. (2) The leading phase current, i.e., phase A current, lags behind the non-faulty phase current, i.e., phase C voltage, by an angle greater than 90° and significantly less than 170°. (3) The voltage amplitudes of the two faulty phases, namely phase A and phase B, are not equal, and the voltage amplitude of the leading phase A is greater than that of the lagging phase B.

[0027] (II) Determination of Metallic Faults An interphase fault is considered a metallic fault if any of the following conditions are met: (1) The lagging phase current, i.e., phase B current, leads the non-faulty phase current, i.e., phase C voltage, by an angle of approximately 10°. (2) The leading phase current of the two faulted phases, namely the A phase current, lags behind the non-faulted phase current, namely the C phase voltage, by an angle of approximately 170°. (3) The voltage amplitudes of the two faulted phases, namely phase A and phase B, are equal, and the voltages of phase A and phase B are symmetrically distributed with respect to the voltage of the non-faulted phase, namely phase C.

[0028] Step S5 determines the fault location of the phase-to-phase fault. Based on the phase relationship between the voltages of the two faulty phases, and combined with formula calculations, the qualitative determination and quantitative calculation of the phase-to-phase fault location are achieved. Specifically, this includes two parts: qualitative determination of the fault location and quantitative calculation of the fault distance. (1) Qualitative judgment of fault location If the voltages of the two faulty phases, namely phase A and phase B, are in phase, and the voltages of phase A and phase B are opposite to the voltage of the non-faulty phase, namely phase C, then the fault between the phases is determined to be a fault at the output of the transmission line. If the phase difference between the two faulty phases, namely phase A and phase B, is smaller than the phase difference when the power system is operating normally, the distance of the fault point can be judged based on the degree of change in the phase difference. The farther the fault point is from the measurement point, the greater the phase difference between phase A and phase B.

[0029] (2) Quantitative calculation of fault location The phase difference between the voltages of the two faulty phases is calculated using the following formula, and then the actual fault distance between the fault point and the measurement point is calculated using the fault distance formula. The specific formula is as follows: Formula for calculating the cosine of the phase difference between two faulty phase voltages:

[0030] In the formula, This represents the phase difference between the voltages of the two faulty phases, namely phase A and phase B. , These are the phase voltage amplitudes of phase A and phase B, respectively. This represents the line voltage amplitude between phase A and phase B.

[0031] Fault distance calculation formula: =

[0032] In the formula, The distance between the fault point and the measurement point. This represents the impedance per unit length of the transmission line. This refers to the amplitude of the line current between phases A and B. This refers to the phase current amplitude of the faulty phase A. Since the current amplitudes of the two faulty phases in this invention are equal and their directions are opposite, the phase current amplitude of phase A is... Phase B phase current amplitude Equal, line current amplitude =2× .

[0033] The phase difference between the two faulty phase voltages and the specific fault distance can be calculated using the above formula. Combined with the qualitative judgment results, the location of the interphase fault point can be accurately determined.

[0034] Corresponding to the phase-to-phase fault nature determination method in Embodiment 1 of the present invention, Embodiment 2 of the present invention also provides a phase-to-phase fault nature determination device, comprising: One or more processors; Memory; One or more applications, wherein the one or more applications are stored in the memory and configured to be executed by the one or more processors, and the one or more applications are configured to perform the phase-to-phase fault nature determination method.

[0035] Corresponding to the phase-to-phase fault nature determination method in Embodiment 1 of the present invention, Embodiment 3 of the present invention also provides a computer program product, including computer instructions, wherein the computer instructions instruct a computer device to perform the operation corresponding to the phase-to-phase fault nature determination method.

[0036] Preferably, the processor can be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor can be a microprocessor, or the processor can be any conventional processor. The processor is the control center of the device, connecting various parts of the device through various interfaces and lines.

[0037] The memory mainly includes a program storage area and a data storage area. The program storage area can store the operating system, applications required for at least one function, etc., while the data storage area can store related data, etc. Furthermore, the memory can be a high-speed random access memory, or a non-volatile memory, such as a plug-in hard drive, a SmartMedia Card (SMC), a Secure Digital (SD) card, and a Flash Card, or other volatile solid-state storage devices.

[0038] It should be noted that the above-mentioned devices may include, but are not limited to, processors and memory, as will be understood by those skilled in the art.

[0039] For the working principle and process of the above embodiments, please refer to the description of Embodiment 1 of the present invention, which will not be repeated here.

[0040] Compared with existing technologies, this invention has the following significant advantages: Based on power system fault recording files, this invention sequentially completes the accurate determination of phase-to-phase faults, identification of fault direction (forward and reverse), differentiation of fault nature (metallic and through transition resistance), and qualitative and quantitative calculation of fault location. This overcomes the limitations of existing technologies, which can only preliminarily identify phase-to-phase fault categories, and achieves a systematic and comprehensive analysis of the core characteristics of phase-to-phase faults. This invention relies on multi-dimensional feature cross-validation of voltage, current, and zero-sequence components to form judgment rules, and combines this with a dedicated formula to quantitatively calculate fault distance. This avoids the problem of misjudgment caused by single-feature judgment, and achieves accurate identification of fault features and quantitative location of faults, significantly improving the accuracy and reliability of phase-to-phase fault diagnosis. Simultaneously, this invention provides relay protection professionals with comprehensive and accurate fault feature data, effectively supporting the optimization of relay protection strategies, enhancing the rapid response capability of power system fault diagnosis, meeting the actual needs of modern smart grids for accurate fault diagnosis and self-healing control, and ensuring the safe and stable operation of the power system.

[0041] The above description is merely a preferred embodiment of the present invention and should not be construed as limiting the scope of the invention. Therefore, any equivalent variations made in accordance with the claims of the present invention are still within the scope of the present invention.

Claims

1. A method for determining the nature of phase-to-phase faults, characterized in that, include: Step S1: Obtain the fault recording file of the power system and extract the three-phase voltage data and three-phase current data from the fault recording file; Step S2: Based on the three-phase voltage data and three-phase current data, determine whether a phase-to-phase fault has occurred. If a phase-to-phase fault is determined, identify the faulty phase and the non-faulty phase. Step S3: Based on the phase relationship between the current of the two faulty phases and the voltage of the non-faulty phases, determine whether the fault direction of the interphase fault is a positive or negative fault. Step S4: Based on the phase relationship between the current of the two faulty phases and the voltage of the non-faulty phases, and the voltage amplitude relationship between the two faulty phases, determine whether the fault nature of the interphase fault is a metallic fault or a fault through a transition resistor. Step S5: Determine the fault location of the interphase fault based on the voltage phase relationship between the two faulty phases.

2. The method according to claim 1, characterized in that, In step S2, a phase-to-phase fault is determined to have occurred when all of the following conditions are met: Two of the three-phase voltages have reduced amplitude, while the voltage amplitude and phase of the remaining phase do not change significantly, and there is no zero-sequence voltage. The amplitudes of the two phase currents corresponding to the voltage drop increase synchronously at the moment of voltage drop, there is no zero-sequence current, and the amplitudes of the two phases with increasing current are equal but opposite in phase; At the same time, the two phases with decreased voltage and increased current are identified as faulty phases, and the remaining phase is identified as a non-faulty phase.

3. The method according to claim 1, characterized in that, In step S3, the phase-to-phase fault is determined to be a positive-direction fault if any of the following conditions are met: In a two-phase fault phase current, the lagging phase current leads the non-fault phase voltage by 10°~90°. In a two-phase fault current, the leading phase current lags the non-fault phase voltage by 90°~170°.

4. The method according to claim 1, characterized in that, In step S4, the phase-to-phase fault is determined to be a fault via the transition resistor if any of the following conditions are met: The angle by which the lagging phase current in the two-phase fault current leads the non-fault phase voltage is greater than 10° and less than 90°. The leading phase current in the two-phase fault current lags the non-fault phase voltage by an angle greater than 90° and less than 170°. The voltage amplitudes of the two faulty phases are not equal, and the voltage amplitude of the leading phase is greater than that of the lagging phase.

5. The method according to claim 1, characterized in that, In step S4, the interphase fault is determined to be a metallic fault if any of the following conditions are met: The angle by which the lagging phase current in the two-phase fault current leads the non-faulty phase voltage is 10°. The leading phase current in the two-phase fault current lags the non-fault phase voltage by an angle of 170°. The voltage amplitudes of the two faulty phases are equal, and the voltages of the two faulty phases are symmetrical about the voltages of the non-faulty phases.

6. The method according to claim 1, characterized in that, In step S5, when the voltages of the two faulty phases are in phase and opposite to the voltages of the non-faulty phases, the phase-to-phase fault is determined to be a fault at the line outlet. The phase difference between the voltages of the two faulty phases is smaller than the phase difference during normal operation, and the farther the distance between the fault point and the measurement point, the greater the phase difference between the voltages of the two faulty phases.

7. The method according to claim 1, characterized in that, In step S5, the cosine value of the voltage phase difference between the two faulty phases is calculated using the following formula: in, This represents the phase difference between the voltages of the two faulty phases, namely phase A and phase B. , These are the phase voltage amplitudes of phase A and phase B, respectively. This represents the line voltage amplitude between phase A and phase B.

8. The method according to claim 7, characterized in that, In step S5, the fault distance between the fault point and the measurement point is calculated using the following formula. : = in, This represents the impedance per unit length of the transmission line. This refers to the amplitude of the line current between phases A and B. This represents the phase current amplitude of the faulty phase A.

9. A device for determining the nature of an interphase fault, characterized in that, include: One or more processors; Memory; One or more applications, wherein the one or more applications are stored in the memory and configured to be executed by the one or more processors, and the one or more applications are configured to perform the phase-to-phase fault nature determination method as described in any one of claims 1 to 8.

10. A computer program product, characterized in that, Includes computer instructions that instruct a computer device to perform an operation corresponding to the phase-to-phase fault nature determination as described in any one of claims 1 to 8.

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