Power distribution network fault positioning method and device and electronic equipment

Abstract

The application discloses a power distribution network fault positioning method and device and electronic equipment. The method comprises the following steps: acquiring a zero sequence fault network circuit corresponding to a power distribution network, wherein the zero sequence fault network circuit is a zero sequence network circuit in a fault state; injecting zero sequence current signals at multiple frequencies into a zero sequence power supply of the zero sequence fault network circuit, and determining return zero sequence voltages corresponding to the multiple frequencies, wherein the multiple frequencies comprise a predetermined power frequency, a first frequency, and a second frequency, the first frequency is different from the second frequency, and the return zero sequence voltage is a zero sequence voltage returned by a second parallel structure; determining fault zero sequence admittances corresponding to the multiple frequencies according to the zero sequence current signals and the return zero sequence voltages corresponding to the multiple frequencies; and determining a target fault position of the power distribution network according to reference line parameters corresponding to the power distribution network and the multiple fault zero sequence admittances. The application solves the technical problem that it is difficult to conveniently and accurately perform fault positioning in the related art.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of fault detection, in particular to a power distribution network fault locating method and device and electronic equipment. BACKGROUND

[0002] Under the background of accelerating the construction of new power systems, the large-scale access of distributed energy to power distribution networks leads to a dramatic increase in topology complexity, and its safe operation faces unprecedented challenges. As the core hub supporting new energy consumption and power supply reliability, the fault locating capability of power distribution networks has become a key bottleneck restricting the resilience of power grids. Especially with the extension of line distance and the intensification of environmental interference, the traditional passive detection mode faces fundamental difficulties: the fault traveling wave signal undergoes multiple attenuation and distortion in long-distance transmission, and the weak characteristics are completely overwhelmed by the harmonics of distributed power and background noise; the nonlinear transient component of high resistance grounding fault is difficult to capture due to the lack of effective excitation, resulting in inaccurate fault point identification and delayed isolation, which directly threatens power supply safety.

[0003] At present, no effective solution has been proposed to solve the above problems. SUMMARY

[0004] The embodiments of the present application provide a power distribution network fault locating method, device and electronic equipment to at least solve the technical problem that it is difficult to conveniently and accurately locate faults in the related art.

[0005] According to one aspect of the present invention, a method for locating faults in a distribution network is provided, comprising: acquiring a zero-sequence fault network circuit corresponding to the distribution network, wherein the zero-sequence fault network circuit is a zero-sequence network circuit under fault conditions, the zero-sequence fault network circuit includes a zero-sequence power supply, a neutral point zero-sequence impedance, a first line segment zero-sequence admittance, a second line segment zero-sequence admittance, a line zero-sequence impedance, and a fault transition resistance; one end of the zero-sequence power supply is grounded, and the other end is connected in parallel with one end of the neutral point zero-sequence impedance, the other end of the neutral point zero-sequence impedance is grounded; a first parallel structure of the zero-sequence power supply and the neutral point zero-sequence impedance is connected in parallel with one end of the first line segment zero-sequence admittance, the other end of the first line segment zero-sequence admittance is grounded; a second parallel structure of the first parallel structure and the first line segment zero-sequence admittance is connected in series with one end of the line zero-sequence impedance; the line zero-sequence impedance... The other end is connected in parallel with a third parallel structure, which is a structure formed by connecting one end of a fault transition resistor in parallel with one end of a second line segment zero-sequence admittance. The other end of the fault transition resistor is grounded, and the other end of the second line segment zero-sequence admittance is grounded. Multiple zero-sequence current signals at various frequencies are injected into the zero-sequence power supply of the zero-sequence fault network circuit to determine the return zero-sequence voltage corresponding to each of the multiple frequencies. The multiple frequencies include a predetermined power frequency, a first frequency, and a second frequency, where the first frequency is different from the second frequency. The return zero-sequence voltage is the zero-sequence voltage returned by the second parallel structure. Based on the zero-sequence current signals and return zero-sequence voltages corresponding to the multiple frequencies, the fault zero-sequence admittance corresponding to each of the multiple frequencies is determined. Based on the reference line parameters corresponding to the distribution network and the multiple fault zero-sequence admittances, the target fault location of the distribution network is determined.

[0006] Optionally, determining the target fault location of the distribution network based on the reference line parameters corresponding to the distribution network and multiple fault zero-sequence admittances includes: determining the real and imaginary eigenvalues ​​corresponding to the multiple fault zero-sequence admittances; retrieving the admittance variable equation corresponding to the distribution network, wherein the admittance variable equation includes a real variable equation and an imaginary variable equation, the real variable equation being an equation between the real eigenvalues ​​and the target variable equation, the imaginary variable equation being an equation between the imaginary eigenvalues ​​and the target variable equation, and the target variable equation including a fault location coefficient term and a fault transition resistance term; solving for the target fault coefficient value corresponding to the fault location coefficient term based on the reference line parameters corresponding to the distribution network, the real and imaginary eigenvalues ​​corresponding to the multiple fault zero-sequence admittances, and the admittance variable equation; and determining the target fault location based on the target fault coefficient value.

[0007] Optionally, based on the reference line parameters corresponding to the distribution network, the real and imaginary eigenvalues ​​corresponding to the plurality of fault zero-sequence admittances, and the admittance variable equation, the target fault coefficient value corresponding to the fault location coefficient term is solved, including: inputting the real impedance parameters corresponding to the reference line parameters and the real eigenvalues ​​corresponding to the plurality of fault zero-sequence admittances into the real variable equation to obtain the target real part equations corresponding to the plurality of frequencies; inputting the imaginary impedance parameters corresponding to the reference line parameters and the imaginary eigenvalues ​​corresponding to the plurality of fault zero-sequence admittances into the imaginary variable equation to obtain the target imaginary equations corresponding to the plurality of frequencies; and fitting the plurality of target real part equations and the plurality of target imaginary part equations using the least squares sliding window method to obtain the variable value corresponding to the target variable term, wherein the variable value includes the target fault coefficient value corresponding to the fault location coefficient term.

[0008] Optionally, before solving for the target fault coefficient value corresponding to the fault location coefficient term based on the reference line parameters corresponding to the distribution network, the real and imaginary eigenvalues ​​corresponding to the plurality of fault zero-sequence admittances, and the admittance variable equation, the method further includes: obtaining the zero-sequence normal network circuit corresponding to the distribution network when the admittance variable equation includes initial fixed line parameter terms and intermediate line parameter terms, and the reference line parameters include initial fixed line parameter values ​​and intermediate line parameter values. The zero-sequence normal network circuit is a zero-sequence network circuit in a fault-free state. The zero-sequence normal network circuit includes a zero-sequence power supply, a neutral point zero-sequence impedance, a first line segment zero-sequence admittance, a second line segment zero-sequence admittance, and a line zero-sequence impedance. One end of the zero-sequence power supply is grounded, and the other end is connected to the neutral point zero-sequence impedance. The zero-sequence impedance at the neutral point is grounded at one end, and the zero-sequence power supply and the first parallel structure of the neutral point zero-sequence impedance are connected in parallel with one end of the first line segment zero-sequence admittance. The other end of the first line segment zero-sequence admittance is grounded. The first parallel structure and the second parallel structure of the first line segment zero-sequence admittance are connected in series with one end of the line zero-sequence impedance. The other end of the line zero-sequence impedance is connected in parallel with one end of the second line segment zero-sequence admittance. The other end of the second line segment zero-sequence admittance is grounded. A zero-sequence current signal at the predetermined power frequency is injected into the zero-sequence power supply of the zero-sequence normal network circuit to determine the return zero-sequence voltage corresponding to the predetermined power frequency. The intermediate line parameter values ​​are obtained based on the initial fixed line parameter values, the zero-sequence current signal corresponding to the predetermined power frequency, and the return zero-sequence voltage.

[0009] Optionally, the real part variable equation is expressed by the following formula: The equation for the imaginary part variable is expressed by the following formula: ,in, This is the real part characteristic term corresponding to the zero-sequence admittance term of the fault. This is the imaginary characteristic term corresponding to the zero-sequence admittance term of the fault. For the fault location coefficient term, For the line-to-ground conductivity term, This refers to the line-to-ground capacitance. This refers to the angular frequency term of the zero-sequence current signal at the corresponding frequency. Represents the first algebraic terms. Represents second-generation terms. Represents third-generation terms. Represents the fourth algebraic term; the first algebraic term represents The second algebraic term representation The third algebraic term representation The fourth algebraic term representation Where R0 represents the zero-sequence resistance term and L0 represents the zero-sequence inductance term, This is the fault transition resistance term.

[0010] Optionally, determining the target fault location based on the target fault coefficient value includes: determining the total line length and the position of the zero-sequence current injection end; determining the product of the total line length and the target fault coefficient value to obtain the target length; and taking the position of the zero-sequence current injection end as the starting point and extending the target length towards the end of the line as the target fault location.

[0011] According to one aspect of the present invention, a distribution network fault location system is provided, comprising: a zero-sequence fault network circuit and a controller, wherein the zero-sequence fault network circuit is a zero-sequence network circuit under fault conditions, the zero-sequence fault network circuit includes a zero-sequence power supply, a neutral point zero-sequence impedance, a first line segment zero-sequence admittance, a second line segment zero-sequence admittance, a line zero-sequence impedance, and a fault transition resistor; one end of the zero-sequence power supply is grounded, and the other end is connected in parallel with one end of the neutral point zero-sequence impedance; the other end of the neutral point zero-sequence impedance is grounded; a first parallel structure of the zero-sequence power supply and the neutral point zero-sequence impedance is connected in parallel with one end of the first line segment zero-sequence admittance; the other end of the first line segment zero-sequence admittance is grounded; a second parallel structure of the first parallel structure and the first line segment zero-sequence admittance is connected in series with one end of the line zero-sequence impedance; the other end of the line zero-sequence impedance is connected in parallel with a third parallel structure. The third parallel structure is formed by connecting one end of a fault transition resistor and one end of a second line segment zero-sequence admittance in parallel. The other end of the fault transition resistor is grounded, and the other end of the second line segment zero-sequence admittance is grounded. The controller is used to acquire the zero-sequence fault network circuit corresponding to the distribution network; inject zero-sequence current signals at multiple frequencies into the zero-sequence power supply of the zero-sequence fault network circuit, and determine the return zero-sequence voltage corresponding to each of the multiple frequencies. The multiple frequencies include a predetermined power frequency, a first frequency, and a second frequency. The first frequency is different from the second frequency. The return zero-sequence voltage is the zero-sequence voltage returned by the second parallel structure. Based on the zero-sequence current signals and the return zero-sequence voltage corresponding to the multiple frequencies, the fault zero-sequence admittance corresponding to each of the multiple frequencies is determined. Based on the reference line parameters corresponding to the distribution network and the multiple fault zero-sequence admittances, the target fault location of the distribution network is determined.

[0012] According to one aspect of the present invention, a distribution network fault location device is provided, comprising: an acquisition module, configured to acquire a zero-sequence fault network circuit corresponding to the distribution network, wherein the zero-sequence fault network circuit is a zero-sequence network circuit under fault conditions, the zero-sequence fault network circuit including a zero-sequence power supply, a neutral point zero-sequence impedance, a first line segment zero-sequence admittance, a second line segment zero-sequence admittance, a line zero-sequence impedance, and a fault transition resistance; one end of the zero-sequence power supply is grounded, and the other end is connected in parallel with one end of the neutral point zero-sequence impedance, the other end of the neutral point zero-sequence impedance is grounded; a first parallel structure of the zero-sequence power supply and the neutral point zero-sequence impedance is connected in parallel with one end of the first line segment zero-sequence admittance, the other end of the first line segment zero-sequence admittance is grounded; a second parallel structure of the first parallel structure and the first line segment zero-sequence admittance is connected in series with one end of the line zero-sequence impedance, the other end of the line zero-sequence impedance is connected in parallel with a third parallel structure. The system is configured in parallel, wherein the third parallel structure is formed by connecting one end of a fault transition resistor and one end of a second line segment zero-sequence admittance in parallel, the other end of the fault transition resistor is grounded, and the other end of the second line segment zero-sequence admittance is grounded; a first determining module is used to inject zero-sequence current signals at multiple frequencies into the zero-sequence power supply of the zero-sequence fault network circuit, and determine the return zero-sequence voltage corresponding to each of the multiple frequencies, wherein the multiple frequencies include a predetermined power frequency, a first frequency, and a second frequency, the first frequency being different from the second frequency, and the return zero-sequence voltage being the zero-sequence voltage returned by the second parallel structure; a second determining module is used to determine the fault zero-sequence admittance corresponding to each of the multiple frequencies based on the zero-sequence current signals and the return zero-sequence voltage; and a third determining module is used to determine the target fault location of the distribution network based on the reference line parameters corresponding to the distribution network and the multiple fault zero-sequence admittances.

[0013] According to one aspect of the present invention, an electronic device is provided, comprising: a processor; and a memory for storing processor-executable instructions; wherein the processor is configured to execute the instructions to implement the power distribution network fault location method described in any of the preceding embodiments.

[0014] According to one aspect of the present invention, a computer-readable storage medium is provided, wherein when the instructions in the computer-readable storage medium are executed by a processor of an electronic device, the electronic device is enabled to perform the power distribution network fault location method described above.

[0015] In this embodiment of the invention, a zero-sequence fault network circuit corresponding to a distribution network is obtained. The zero-sequence fault network circuit is a zero-sequence network circuit under fault conditions. The zero-sequence fault network circuit includes a zero-sequence power supply, a neutral point zero-sequence impedance, a first line segment zero-sequence admittance, a second line segment zero-sequence admittance, a line zero-sequence impedance, a fault transition resistor, and a fault transition resistor. One end of the zero-sequence power supply is grounded, and the other end is connected in parallel with one end of the neutral point zero-sequence impedance, which is also grounded. The first parallel structure of the zero-sequence power supply and the neutral point zero-sequence impedance is connected in parallel with one end of the first line segment zero-sequence admittance, which is also grounded. The second parallel structure of the first parallel structure and the first line segment zero-sequence admittance is connected in series with one end of the line zero-sequence impedance, which is connected in series with the third line segment zero-sequence impedance. The parallel structure is formed by connecting one end of the fault transition resistor and one end of the second line segment zero-sequence admittance in parallel. The other end of the fault transition resistor is grounded, and the other end of the second line segment zero-sequence admittance is grounded. Zero-sequence current signals at multiple frequencies are injected into the zero-sequence power supply of the zero-sequence fault network circuit to determine the return zero-sequence voltage corresponding to each frequency. These frequencies include a predetermined power frequency, a first frequency, and a second frequency, where the first and second frequencies are different. The return zero-sequence voltage is the zero-sequence voltage returned by the second parallel structure. Based on the zero-sequence current signals and the return zero-sequence voltage corresponding to each frequency, the fault zero-sequence admittance corresponding to each frequency is determined. Based on the reference line parameters of the distribution network and the multiple fault zero-sequence admittances, the target fault location of the distribution network is determined. By employing multi-frequency zero-sequence signal injection and fault zero-sequence admittance feature fitting, power frequency and two types of different frequency zero-sequence current signals are injected into the zero-sequence fault network. The corresponding return zero-sequence voltage is measured to calculate the fault zero-sequence admittance at each frequency. Combined with the base line parameters of the distribution network, the target fault location in the distribution network is accurately located. This achieves the technical effect of convenient, efficient and high-precision location of grounding faults in the distribution network, thus solving the technical problem of difficulty in convenient and accurate fault location in related technologies. Attached Figure Description

[0016] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this application, illustrate exemplary embodiments of the invention and, together with their description, serve to explain the invention and do not constitute an undue limitation thereof. In the drawings:

[0017] Figure 1 This is a flowchart of a power distribution network fault location method according to an embodiment of the present invention;

[0018] Figure 2 This is a simplified diagram of the zero-order network of the distributed ground parameter system under normal operation, provided by an optional embodiment of the present invention.

[0019] Figure 3This is a simplified diagram of the zero-order network after a fault in a distributed ground parameter system provided by an optional embodiment of the present invention;

[0020] Figure 4 This is a structural block diagram of a power distribution network fault location device according to an embodiment of the present invention. Detailed Implementation

[0021] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0022] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0023] Example 1

[0024] According to an embodiment of the present invention, an embodiment of a method for locating faults in a power distribution network is provided. It should be noted that the steps shown in the flowchart in the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions. Furthermore, although a logical order is shown in the flowchart, in some cases, the steps shown or described may be executed in a different order than that shown here.

[0025] Figure 1 This is a flowchart of a power distribution network fault location method according to an embodiment of the present invention, such as... Figure 1 As shown, the method includes the following steps:

[0026] Step S102: Obtain the zero-sequence fault network circuit corresponding to the distribution network. The zero-sequence fault network circuit is the zero-sequence network circuit under fault conditions. The zero-sequence fault network circuit includes a zero-sequence power supply, a neutral point zero-sequence impedance, a first line segment zero-sequence admittance, a second line segment zero-sequence admittance, a line zero-sequence impedance, a fault transition resistor, one end of the zero-sequence power supply is grounded, and the other end is connected in parallel with one end of the neutral point zero-sequence impedance. The other end of the neutral point zero-sequence impedance is grounded. The first parallel structure of the zero-sequence power supply and the neutral point zero-sequence impedance is connected in parallel with one end of the first line segment zero-sequence admittance. The other end of the first line segment zero-sequence admittance is grounded. The second parallel structure of the first parallel structure and the first line segment zero-sequence admittance is connected in series with one end of the line zero-sequence impedance. The other end of the line zero-sequence impedance is connected in parallel with a third parallel structure. The third parallel structure is a structure formed by connecting one end of the fault transition resistor and one end of the second line segment zero-sequence admittance in parallel. The other end of the fault transition resistor is grounded, and the other end of the second line segment zero-sequence admittance is grounded.

[0027] In step S102 of this application, it is explained that based on the electrical characteristics after a distribution network fault, an equivalent circuit model retaining the zero-sequence component is constructed, and the connection relationship and equivalent parameter definition of each component such as power supply, impedance, admittance, and fault resistance are clarified.

[0028] This involves the power distribution network, which is a power network consisting of distribution lines, distribution transformers, switching equipment, etc., responsible for transmitting electricity from substations to users.

[0029] This involves a zero-sequence fault network circuit, which is a simplified circuit model constructed based on the zero-sequence component equivalence principle after a single-phase ground fault occurs in the distribution network, reflecting the transmission characteristics of zero-sequence current and voltage.

[0030] This involves zero-sequence power sources, which are the excitation sources that inject zero-sequence current signals into the zero-sequence fault network and serve as the signal input locations for fault parameter measurements.

[0031] This involves the neutral point zero-sequence impedance, which is the comprehensive equivalent impedance of all grounding elements between the neutral point of the distribution network and the earth, including components such as the arc suppression coil inductance and the neutral point grounding resistance.

[0032] This involves the zero-sequence admittance of the first line segment, which is the equivalent admittance of the line segment from the fault point to the measurement end. It is calculated from the line-to-ground conductance and capacitance according to the fault location.

[0033] This involves the zero-sequence admittance of the second line segment, which is the equivalent admittance of the line segment from the fault point to the end of the line, and the equivalent parameters of conductance and capacitance to ground calculated according to the remaining length.

[0034] This involves the zero-sequence impedance of the line, which is the zero-sequence equivalent impedance of the line itself, reflecting the zero-sequence characteristics of the line's resistance and inductance.

[0035] This involves the fault transition resistance, which is the equivalent resistance between the fault point and the ground during a single-phase ground fault.

[0036] This involves three parallel structures. The first parallel structure is a circuit node formed by connecting the zero-sequence power supply and the neutral point zero-sequence impedance in parallel, which is the first equivalent node after the zero-sequence signal is injected. The second parallel structure is a circuit node formed by connecting the first parallel structure and the zero-sequence admittance of the first line segment in parallel, which is the measurement point for the return zero-sequence voltage. The third parallel structure is a circuit node formed by connecting the fault transition resistance and the zero-sequence admittance of the second line segment in parallel, which is directly related to the electrical characteristics of the fault point.

[0037] This step simplifies the computational dimension, transforming a complex three-phase fault system into a single-loop zero-sequence network. This avoids computational redundancy caused by three-phase coupling and reduces the complexity of subsequent signal processing and parameter calculation. Focusing on the core fault, the zero-sequence network only reflects the fault-related zero-sequence components, ensuring the model accurately captures fault characteristics. Clearly defining voltage measurement points and current injection points provides a clear physical carrier for subsequent signal injection and data acquisition, ensuring the orderly implementation of subsequent steps.

[0038] Step S104: Inject zero-sequence current signals at multiple frequencies into the zero-sequence power supply of the zero-sequence fault network circuit, and determine the return zero-sequence voltage corresponding to each of the multiple frequencies. The multiple frequencies include a predetermined power frequency, a first frequency, and a second frequency. The first frequency and the second frequency are different. The return zero-sequence voltage is the zero-sequence voltage returned by the second parallel structure.

[0039] In step S104 of this application, zero-sequence current signals of three frequencies—power frequency and two different frequencies—are injected into the zero-sequence fault network through a zero-sequence power supply. Simultaneously, the return zero-sequence voltage corresponding to each frequency is measured at the second parallel structure node, and three sets of corresponding data—frequency, current, and voltage—are obtained.

[0040] This involves zero-sequence current signals, which are zero-sequence component currents with fixed frequency and stable amplitude, used to excite the electrical response of zero-sequence fault networks.

[0041] This involves multiple frequencies, which are signal sets containing at least three specific frequencies: a predetermined power frequency, a first alternative frequency, and a second alternative frequency. The two alternative frequencies are different from each other and distinct from the power frequency.

[0042] This involves the predetermined power frequency, which is the rated frequency for normal operation of the distribution network and reflects the inherent power frequency characteristics of the system under fault conditions.

[0043] This involves a first frequency, which is a different frequency signal from the power frequency. This signal is used to avoid power frequency harmonics and load interference, and to improve signal recognition.

[0044] This involves a second frequency, which is a different frequency signal from both the power frequency and the first frequency, further enriching the signal feature dimensions.

[0045] This involves the return zero-sequence voltage, which is the zero-sequence component voltage generated at the second parallel structure node after the zero-sequence current signal is injected.

[0046] This step enhances anti-interference capabilities, as the inter-frequency signal avoids harmonic and load fluctuation interference from the power grid, resolving the issue of single-frequency signals being susceptible to environmental influences and ensuring the stability and accuracy of measurement data. It also enriches the feature dimensions; the three frequencies correspond to three sets of voltage and current data, allowing for the generation of six admittance features. This provides sufficient samples for subsequent fitting and solving to determine the corresponding fault location. The data exhibits strong correlation; the current injection point and voltage measurement point are clearly defined, and the data directly reflects the equivalent admittance characteristics of the zero-sequence network, providing accurate raw input for fault zero-sequence admittance calculation.

[0047] Step S106: Determine the fault zero-sequence admittance corresponding to each of the multiple frequencies based on the zero-sequence current signals and the return zero-sequence voltages corresponding to the multiple frequencies respectively.

[0048] In step S106 provided in this application, according to the definition of admittance, the zero-sequence current signal phasor at each frequency is divided by the corresponding return zero-sequence voltage phasor to obtain the fault zero-sequence admittance at each frequency. Optionally, it may include real and imaginary features.

[0049] This involves the fault zero-sequence admittance, which is the equivalent admittance of the zero-sequence network under fault conditions. It is in complex form and includes real and imaginary parts. The real part reflects the active power loss characteristics, while the imaginary part reflects the reactive power characteristics.

[0050] This step enables efficient data conversion, transforming raw current and voltage time-domain data into admittance parameters that directly reflect the characteristics of the fault network. This achieves accurate conversion from raw data to characteristic parameters, simplifying subsequent analysis processes.

[0051] Step S108: Determine the target fault location of the distribution network based on the baseline line parameters and multiple fault zero-sequence admittances corresponding to the distribution network.

[0052] In step S108 provided in this application, the target fault location of the distribution network is determined based on the reference line parameters corresponding to the distribution network and multiple fault zero-sequence admittances.

[0053] Optionally, the reference line parameters can be substituted into the zero-sequence admittance theoretical model and combined with the fault zero-sequence admittance data at three frequencies. The fault location coefficient can be solved by fitting using the least squares method, and then converted into the actual fault location by combining the total line length.

[0054] This involves reference line parameters, which are inherent line parameters obtained through measurement during the normal operation of the system. These parameters may include zero-sequence resistance, zero-sequence inductance, conductance to ground, and capacitance to ground, and serve as the baseline known quantities for fault analysis.

[0055] This involves the target fault location, which is the actual physical location of a single-phase ground fault in the distribution network and is the final output result of fault location.

[0056] This step improves positioning accuracy. If an overdetermined equation set is constructed based on multi-frequency admittance characteristics during the process, the effects of transition resistance and measurement errors can be effectively offset, enhancing the reliability of fault location. Furthermore, the reference line parameters already include inherent or known characteristics of the line, and the fitting process can automatically adapt to parameter differences between different lines without manual adjustment, making it suitable for various distribution network lines. Finally, the actual physical distance from the measurement end to the fault point is output, allowing maintenance personnel to directly troubleshoot faults based on distance, solving the problems of vague positioning and the need for extensive on-site investigations required by traditional methods, significantly improving fault handling efficiency.

[0057] Through the above steps S102-S108, the zero-sequence fault network circuit corresponding to the distribution network is obtained. The zero-sequence fault network circuit is the zero-sequence network circuit under fault conditions. The zero-sequence fault network circuit includes a zero-sequence power supply, a neutral point zero-sequence impedance, a first line segment zero-sequence admittance, a second line segment zero-sequence admittance, a line zero-sequence impedance, a fault transition resistor, and a fault transition resistor. One end of the zero-sequence power supply is grounded, and the other end is connected in parallel with one end of the neutral point zero-sequence impedance, which is also grounded. The first parallel structure of the zero-sequence power supply and the neutral point zero-sequence impedance is connected in parallel with one end of the first line segment zero-sequence admittance, which is also grounded. The second parallel structure of the first parallel structure and the first line segment zero-sequence admittance is connected in series with one end of the line zero-sequence impedance, which is also grounded. The circuit is connected in parallel with a third parallel structure, which is formed by connecting one end of the fault transition resistor and one end of the second line segment zero-sequence admittance in parallel. The other end of the fault transition resistor is grounded, and the other end of the second line segment zero-sequence admittance is grounded. Zero-sequence current signals at multiple frequencies are injected into the zero-sequence power supply of the zero-sequence fault network circuit to determine the return zero-sequence voltage corresponding to each of the multiple frequencies. The multiple frequencies include a predetermined power frequency, a first frequency, and a second frequency. The first frequency and the second frequency are different. The return zero-sequence voltage is the zero-sequence voltage returned by the second parallel structure. Based on the zero-sequence current signals and the return zero-sequence voltage corresponding to the multiple frequencies, the fault zero-sequence admittance corresponding to each of the multiple frequencies is determined. Based on the reference line parameters of the distribution network and the multiple fault zero-sequence admittances, the target fault location of the distribution network is determined. By employing multi-frequency zero-sequence signal injection and fault zero-sequence admittance feature fitting, power frequency and two types of different frequency zero-sequence current signals are injected into the zero-sequence fault network. The corresponding return zero-sequence voltage is measured to calculate the fault zero-sequence admittance at each frequency. Combined with the base line parameters of the distribution network, the target fault location in the distribution network is accurately located. This achieves the technical effect of convenient, efficient and high-precision location of grounding faults in the distribution network, thus solving the technical problem of difficulty in convenient and accurate fault location in related technologies.

[0058] As an optional embodiment, the target fault location of the distribution network is determined based on the reference line parameters corresponding to the distribution network and multiple fault zero-sequence admittances. This includes: determining the real and imaginary eigenvalues ​​corresponding to the multiple fault zero-sequence admittances; retrieving the admittance variable equation corresponding to the distribution network, wherein the admittance variable equation includes real and imaginary variable equations, the real variable equation being an equation between the real eigenvalues ​​and the target variable equation, and the imaginary variable equation being an equation between the imaginary eigenvalues ​​and the target variable equation, the target variable equation including the fault location coefficient and the fault transition resistance; solving for the target fault coefficient value corresponding to the fault location coefficient based on the reference line parameters corresponding to the distribution network, the real and imaginary eigenvalues ​​corresponding to the multiple fault zero-sequence admittances, and the admittance variable equation; and determining the target fault location based on the target fault coefficient value.

[0059] This embodiment describes the specific steps for determining the location of the target fault.

[0060] This involves real part eigenvalues, which are specific values ​​of the real part of the zero-sequence admittance for each fault, reflecting the active power loss characteristics of the zero-sequence fault network.

[0061] This involves the imaginary part eigenvalue, which is the specific value of the imaginary part of the zero-sequence admittance of each fault, reflecting the reactive power characteristics (capacitive or inductive effect) of the zero-sequence fault network.

[0062] This involves admittance variable equations, which are a set of equations describing the mathematical relationship between the zero-sequence admittance characteristics of the fault and the target variable. They are the core model connecting measurement data and fault parameters.

[0063] This involves real part variable equations, which are components of admittance variable equations and describe the quantitative relationship between real part characteristic terms and target variable terms.

[0064] This involves the imaginary part variable equation, which is a component of the admittance variable equation and describes the quantitative relationship between the imaginary part characteristic term and the target variable term.

[0065] This involves real part characteristic terms, which are mathematical expressions of the real part characteristic values ​​in real part variable equations, and are the known quantities in the equation.

[0066] This involves the objective variable, which is the mathematical expression of the parameter to be solved in the admittance variable equation. It is the unknown part of the equation.

[0067] This involves the imaginary part characteristic term, which is the mathematical expression of the imaginary part characteristic value in the imaginary part variable equation, and is the known quantity part of the equation.

[0068] This includes the fault location coefficient term, which is a component of the target variable term and is the mathematical expression of the fault location coefficient, directly related to the distance ratio of the fault point.

[0069] This includes the fault transition resistance term, which is a component of the target variable term and is the mathematical expression of the fault transition resistance, reflecting the conductivity between the fault point and the ground.

[0070] This involves the target fault coefficient value, which is the specific value of the fault location coefficient obtained by solving the admittance variable equation. It is a key intermediate parameter for converting the actual fault location.

[0071] This step clarifies the specific implementation process for determining the target fault location based on baseline line parameters and multiple fault zero-sequence admittances. First, the real and imaginary eigenvalues ​​corresponding to each fault zero-sequence admittance are extracted. Then, the admittance variable equation, which includes both real and imaginary variable equations (containing two types of target variable terms: fault location coefficient and fault transition resistance), is retrieved. Finally, combining the baseline line parameters, the real and imaginary eigenvalues ​​are substituted into the admittance variable equation to solve for the target fault coefficient value, thereby determining the target fault location in the distribution network.

[0072] This method enables more precise feature characterization by extracting both real and imaginary feature values, comprehensively capturing the complete electrical characteristics of zero-sequence admittance at different frequencies. The admittance variable equation clarifies the quantitative relationship between feature values ​​and target variables (fault location coefficient, fault transition resistance), providing a rigorous mathematical model to support the solution process, avoiding blind calculations, and improving the standardization and reliability of the solution. Combining multiple sets of real and imaginary feature values ​​corresponding to multiple frequencies to form an overdetermined system of equations can effectively offset the influence of interference factors such as measurement errors and transition resistance fluctuations, solving the problem of insufficient accuracy in solving single features or single frequencies. Moreover, it enables more direct result conversion; the target fault coefficient value obtained can be quickly combined with the total line length to convert into the actual fault location without additional complex processing, providing intuitive and usable results for subsequent operation and maintenance troubleshooting, and ensuring the efficiency of fault location.

[0073] As an optional embodiment, based on the reference line parameters corresponding to the distribution network, the real and imaginary eigenvalues ​​corresponding to multiple fault zero-sequence admittances, and the admittance variable equation, the target fault coefficient value corresponding to the fault location coefficient term is solved. This includes: inputting the real impedance parameters corresponding to the reference line parameters and the real eigenvalues ​​corresponding to multiple fault zero-sequence admittances into the real variable equation to obtain the target real part equation corresponding to multiple frequencies; inputting the imaginary impedance parameters corresponding to the reference line parameters and the imaginary eigenvalues ​​corresponding to multiple fault zero-sequence admittances into the imaginary variable equation to obtain the target imaginary variable equation corresponding to multiple frequencies; and fitting multiple target real part equations and multiple target imaginary part equations using the least squares sliding window method to obtain the variable value corresponding to the target variable term, wherein the variable value includes the target fault coefficient value corresponding to the fault location coefficient term.

[0074] In this embodiment, the steps for determining the target fault coefficient value are described.

[0075] This involves the real impedance parameter, which is the parameter corresponding to the real part of the impedance in the reference line parameter. It is mainly the zero-sequence resistance of the line, which reflects the active power loss characteristics of the line.

[0076] This involves the imaginary impedance parameter, which is the parameter corresponding to the imaginary part of the impedance in the reference line parameters. It is mainly the inductive reactance converted from the zero-sequence inductance of the line, reflecting the inductive reactive characteristics of the line.

[0077] This involves least squares sliding window fitting, a numerical solution method that uses a sliding window to traverse the possible parameter range and minimize the sum of squared errors between the theoretically calculated values ​​and the actual measured values, thereby obtaining the optimal parameter solution.

[0078] This involves variable values, which are the specific numerical values ​​of the target variable terms obtained through fitting and solving. These values ​​are the quantitative results reflecting the core parameters of the fault.

[0079] This step clarifies the specific operational procedure for solving the target fault coefficient value. First, real and imaginary impedance parameters are extracted from the reference line parameters and matched with the real and imaginary eigenvalues ​​of multiple fault zero-sequence admittances. These are then substituted into the real and imaginary variable equations to obtain the target real and imaginary equations for each frequency. Next, the least squares sliding window fitting method is used to jointly solve all the target real and imaginary equations, ultimately yielding the variable values ​​including the target fault coefficient value.

[0080] This method achieves higher solution accuracy. The core advantage of the least squares method is its ability to minimize the sum of squared errors between theoretical and measured values, effectively offsetting measurement deviations in individual equations. By combining multiple sets of real and imaginary equations corresponding to multiple frequencies and solving them simultaneously, an overdetermined system of equations is formed. This significantly reduces solution errors caused by transition resistance and line parameter fluctuations, improving the accuracy of the target fault coefficient values. Furthermore, it offers greater adaptability. The sliding window fitting method can traverse the possible fault location coefficients across the entire line length without pre-setting the fault range, adapting to distribution network lines of different lengths and parameter distributions, avoiding solution failures due to initial assumption biases. It also improves solution stability. Through the joint fitting of multiple sets of equations, the stability and reliability of the target fault coefficient values ​​are ensured.

[0081] As an optional embodiment, before solving for the target fault coefficient value corresponding to the fault location coefficient term based on the reference line parameters corresponding to the distribution network, the real and imaginary eigenvalues ​​corresponding to multiple fault zero-sequence admittances, and the admittance variable equation, the method further includes: obtaining the zero-sequence normal network circuit corresponding to the distribution network when the admittance variable equation includes initial fixed line parameter terms and intermediate line parameter terms, and the reference line parameters include initial fixed line parameter values ​​and intermediate line parameter values. The zero-sequence normal network circuit is the zero-sequence network circuit in a fault-free state. The zero-sequence normal network circuit includes a zero-sequence power supply, a neutral point zero-sequence impedance, a first line segment zero-sequence admittance, a second line segment zero-sequence admittance, a line zero-sequence impedance, and one end of the zero-sequence power supply is grounded, while the other end... One end of the zero-sequence impedance at the neutral point is connected in parallel with the other end of the zero-sequence impedance at the neutral point, and the other end of the zero-sequence impedance at the neutral point is grounded. The first parallel structure of the zero-sequence power supply and the zero-sequence impedance at the neutral point is connected in parallel with one end of the zero-sequence admittance of the first line segment, and the other end of the zero-sequence admittance of the first line segment is grounded. The second parallel structure of the first parallel structure and the zero-sequence admittance of the first line segment is connected in series with one end of the zero-sequence impedance of the line, and the other end of the zero-sequence impedance of the line is connected in parallel with one end of the zero-sequence admittance of the second line segment, and the other end of the zero-sequence admittance of the second line segment is grounded. A zero-sequence current signal at a predetermined power frequency is injected into the zero-sequence power supply of the zero-sequence normal network circuit to determine the return zero-sequence voltage corresponding to the predetermined power frequency. Based on the initial fixed line parameter values, the zero-sequence current signal corresponding to the predetermined power frequency, and the return zero-sequence voltage, the intermediate line parameter values ​​are obtained.

[0082] In this embodiment, the process for obtaining intermediate line parameter values ​​is clearly defined.

[0083] This involves the initial fixed line parameter term, which is a pre-defined, relatively stable mathematical expression of the line parameters in the admittance variable equation, and is the basic known part of the equation.

[0084] This involves intermediate line parameter terms, which are mathematical expressions related to line parameters that need to be solved through normal state measurements in the admittance variable equation. They supplement and improve the initial fixed line parameter terms.

[0085] This involves baseline line parameters, which are a set of inherent electrical parameters of the line obtained through measurement and calculation during the normal operation of the system. They include initial fixed line parameter values ​​and intermediate line parameter values, providing a complete baseline for fault analysis.

[0086] This involves initial fixed line parameter values, which are specific, relatively stable values ​​predetermined in the baseline line parameters and can be used directly without additional measurement.

[0087] This involves intermediate line parameter values, which are specific values ​​obtained from the baseline line parameters through injection measurements under normal conditions. These intermediate line parameters are used to complete the baseline line parameters and improve the accuracy of the model.

[0088] This involves a zero-sequence normal network circuit, which is a simplified circuit model constructed based on the zero-sequence component equivalence principle when the distribution network is not faulty. It only reflects the transmission characteristics of zero-sequence current and voltage under normal conditions.

[0089] In this step, the zero-sequence normal network circuit when the distribution network is fault-free is first obtained, and its component composition and connection relationship are clarified. Then, a zero-sequence current signal of predetermined power frequency is injected into the zero-sequence power supply of the circuit, and the corresponding return zero-sequence voltage is determined. Finally, combined with the existing initial fixed line parameter values, the injected zero-sequence current signal and the measured return zero-sequence voltage, the intermediate line parameter values ​​are calculated to complete the reference line parameters.

[0090] This method enhances parameter completeness. The admittance variable equation includes both initial fixed line parameter terms and intermediate line parameter terms. The corresponding baseline line parameters are supplemented by initial values ​​plus intermediate values ​​obtained from measurement, forming a complete parameter system that provides more comprehensive parameter support for subsequent fault location. Intermediate line parameter values ​​are obtained through actual injection measurements of the zero-sequence normal network circuit. Based on data from the system's normal operating state, this avoids interference from factors such as fault points and transition resistance under fault conditions. The measurement results more closely match the actual electrical characteristics of the line, improving the reliability of the baseline line parameters. Supplementing intermediate line parameter values ​​through normal state measurements dynamically adapts to subtle changes in line parameters (such as line resistance fluctuations caused by ambient temperature), preventing the initial fixed parameters from becoming out of sync with actual line characteristics after long-term use. This makes the admittance variable equation more closely reflect the actual situation of the distribution network, indirectly improving the accuracy of subsequent fault location. Moreover, the injected signal is a predetermined power frequency signal, consistent with the normal operating frequency of the distribution network. The signal transmission characteristics better conform to the inherent laws of the line. Compared to signals of different frequencies, it can more accurately reflect the parameter characteristics of the line under actual operating conditions, ensuring the practicality and effectiveness of the intermediate line parameter values.

[0091] It should be noted that this application describes two circuits: a zero-sequence normal network circuit and a zero-sequence fault network circuit. The structural difference between the two lies in the presence or absence of a fault transition resistor. In the zero-sequence normal network circuit, no fault occurs, and the entire circuit has no additional fault conduction path. In the zero-sequence fault network circuit, after a single-phase ground fault occurs, a fault transition resistor is added at the fault point, forming a conduction structure where the fault transition resistor and the second line segment zero-sequence admittance are connected in parallel. Since the fault transition resistor becomes a new conduction path for the zero-sequence current, it is also the core fault element that changes the electrical characteristics of the zero-sequence network. After a fault occurs, the connection of the fault transition resistor changes the equivalent admittance characteristics of the zero-sequence network (both the real and imaginary parts change). By injecting multi-frequency signals through this circuit, the fault zero-sequence admittance containing fault information can be obtained, thereby establishing the correlation between the reference parameters, fault admittance, and fault location, ultimately calculating the fault location. Without the fault circuit, fault characteristics cannot be quantified, and thus, fault location cannot be achieved. By comparing the characteristic changes of the fault state with the reference parameters of the normal state, fault location is achieved.

[0092] As an optional embodiment, the real part of the equation is expressed by the following formula: The equation for the imaginary part of the variable is expressed by the following formula: ,in, This is the real part characteristic term corresponding to the zero-sequence admittance term of the fault. This is the imaginary characteristic term corresponding to the zero-sequence admittance term of the fault. For the fault location coefficient term, For the line-to-ground conductivity term, This refers to the line-to-ground capacitance. This refers to the angular frequency term of the zero-sequence current signal at the corresponding frequency. Represents the first algebraic terms. Represents second-generation terms. Represents third-generation terms. Represents fourth-generation algebraic terms; first-generation algebraic terms are represented as... Second-generation algebraic term representation Third-generation algebraic term representation Fourth algebraic term representation Where R0 represents the zero-sequence resistance term and L0 represents the zero-sequence inductance term, This is the fault transition resistance term.

[0093] In this embodiment, the specific mathematical expressions for the real part variable equation and the imaginary part variable equation are clearly defined, and each algebraic term is defined ( , , The composition of (p, E), and the parameters (p, E) , ,ω, , By using the roles of R_f, a quantitative relationship model was established between the real and imaginary characteristics of the zero-sequence admittance and the fault location coefficient and fault transition resistance.

[0094] This involves Real(YΣ), which is the real part characteristic term corresponding to the fault zero-sequence admittance. It is the known measured value part in the real part variable equation and reflects the active power loss characteristics of the fault zero-sequence network.

[0095] Among them, Imag(YΣ) is involved, which is the imaginary characteristic term corresponding to the fault zero-sequence admittance. It is the known measured value part in the imaginary variable equation, reflecting the reactive characteristics (capacitive or inductive effect) of the fault zero-sequence network.

[0096] Among them, the fault location coefficient term p is involved, which is the ratio of the distance from the fault location to the measurement end to the total length of the line, and is one of the core objective variables to be solved.

[0097] Among them, it involves The line-to-ground conductivity term is the equivalent lumped parameter of the line-to-ground conductivity per unit length. It reflects the active power leakage characteristics of the line to ground and belongs to the baseline line parameters.

[0098] Among them, it involves The line-to-ground capacitance term is the equivalent lumped parameter of the line-to-ground capacitance per unit length. It reflects the capacitive reactive characteristics of the line to ground and is a baseline line parameter.

[0099] This involves the ω angular frequency term, which corresponds to the angular frequency of the injected zero-sequence current signal (such as the power frequency angular frequency of 100π rad / s), and is a frequency-related parameter in the admittance variable equation.

[0100] Among them, it involves (ω) is the first algebraic term, derived from (1-p)ω The mathematical expression formed is an intermediate calculation term in the admittance variable equation, which relates the fault location coefficient and the line-to-ground capacitance.

[0101] Among them, it involves (ω) is a second algebraic term, derived from 1+p E-pω The mathematical expression formed by (ω) is an intermediate calculation term in the admittance variable equation, which is related to the fault location coefficient, line zero-sequence resistance, inductance and other algebraic terms.

[0102] Among them, it involves (ω) is a third algebraic term, derived from pω E+p The mathematical expression consisting of (ω) is an intermediate calculation term in the admittance variable equation, which is related to the fault location coefficient, line zero-sequence inductance, resistance and other algebraic terms.

[0103] This involves the fourth-generation terms of E, which are (1-p) The mathematical expression consisting of +1 / (3Rf) is an intermediate calculation term in the admittance variable equation, which is related to the fault location coefficient, line-to-ground conductance, and fault transition resistance.

[0104] Among them, it involves The zero-sequence resistance term, or zero-sequence equivalent resistance, reflects the active power loss characteristics of the line and is a baseline line parameter.

[0105] Among them, it involves The zero-sequence inductance of the line, also known as the zero-sequence equivalent inductance, reflects the inductive reactive characteristics of the line and is a baseline line parameter.

[0106] Among them, the R_f fault transition resistance term is involved. The equivalent resistance between the fault point and the ground during a single-phase ground fault is one of the core objective variables to be solved.

[0107] This method improves accuracy by defining detailed algebraic terms and constructing equations, thus integrating fault location coefficients, fault transition resistances, and inherent line parameters. , , , The model deeply couples the real and imaginary parts of the fault zero-sequence admittance (fZ) with the frequency parameter (ω), comprehensively characterizing the real and imaginary parts of the fault zero-sequence admittance. This avoids feature loss due to model simplification and provides precise mathematical support for fault parameter solving. Each algebraic term is explicitly associated with key variables such as fault location, line parameters, and transition resistance, making the physical meaning of the admittance variable equation clear and traceable. This facilitates understanding the transmission logic of fault characteristics and provides a clear parameter association path for subsequent fitting solutions. Furthermore, the model is highly operable, with a clear equation structure and explicit input-output relationships for each parameter. Whether substituting baseline line parameters or importing fault zero-sequence admittance characteristic values, there are clear corresponding terms, facilitating numerical solutions in engineering applications and lowering the technical threshold for model application. It also improves anti-interference capabilities. The real and imaginary parts of the equation constrain the fault parameters from both active and reactive power dimensions, forming a dual constraint on the fault location coefficient and transition resistance. This effectively counteracts interference from measurement errors and line parameter fluctuations, improving the stability of the solution results.

[0108] As an optional embodiment, the target fault location is determined based on the target fault coefficient value, including: determining the total line length and the position of the zero-sequence current injection end; determining the product of the total line length and the target fault coefficient value to obtain the target length; and determining the position of the target fault location by extending the target length from the position of the zero-sequence current injection end towards the end of the line.

[0109] In this embodiment, the specific details of determining the target fault location are described.

[0110] This involves the total line length, which is the actual physical length of the distribution network line from the zero-sequence current injection point to the end of the line. It is a basic known quantity for fault location conversion and is usually specified in the distribution network design data or operation and maintenance log.

[0111] This involves the location of the zero-sequence current injection terminal, which is the physical endpoint where the zero-sequence current signal is injected into the zero-sequence network. It is the reference starting point for fault location and corresponds to the access point of the zero-sequence power supply in the zero-sequence fault network (such as the substation outgoing line terminal).

[0112] This involves the target length, which is the product of the total line length and the target fault coefficient value. It is the actual physical distance from the fault point to the zero-sequence current injection end, and is the result of the conversion from a proportional relationship to an absolute length.

[0113] This process involves first determining two fundamental pieces of information: the total length of the line and the location of the zero-sequence current injection point. Then, by multiplying the total line length by the target fault coefficient value, the actual physical distance (target length) from the fault point to the injection point is obtained. Finally, starting from the zero-sequence current injection point, the target length is extended towards the end of the line, and the endpoint of this extension is the target fault location.

[0114] This method, from basic information confirmation to proportional conversion and physical location determination, is linear and easy to understand, avoiding the cognitive barriers caused by complex model conversions and facilitating rapid mastery and application by maintenance personnel. The conversion results are accurate and reliable, strictly adhering to the definition of the fault location coefficient distance ratio. The actual distance is directly obtained by multiplying the total line length by the coefficient, eliminating errors caused by human estimation or model approximation and ensuring the accuracy of the location results. Furthermore, it is highly practical in the field. The location method, starting from the zero-sequence current injection end and extending towards the end of the line, perfectly matches the actual power supply topology from the injection end to the end of the distribution network. Maintenance personnel can directly troubleshoot along the line according to this logic, significantly improving the efficiency of fault handling.

[0115] Based on the above embodiments and optional embodiments, an optional implementation method is provided, which is described in detail below.

[0116] In related technologies, current fault location techniques for distribution networks mainly rely on impedance methods, traveling wave methods, and distribution network automation methods, but all have significant limitations. The core drawback of the impedance method lies in its high sensitivity to the accuracy of line parameters and transition resistance. Uncertainties in line parameters and high transition resistance significantly amplify ranging errors, leading to insufficient reliability of the location results. The traveling wave method faces applicability bottlenecks in distribution networks. Its theory relies on a clear traveling wave propagation path and accurate wavefront detection, but the multi-branch, short-distance topology of distribution networks leads to complex traveling wave signal reflections and severe wavefront distortion. Simultaneously, high-frequency noise interference and synchronization difficulties in distributed architectures further restrict the practical accuracy of this method.

[0117] While distribution network automation methods can improve positioning capabilities through multi-node information fusion, they face both economic and technical constraints. The deployment of numerous sensors and smart terminals increases construction and maintenance costs, and the complex system structure also increases the difficulty of fault diagnosis. Recent research has attempted to introduce high-precision measurement equipment to improve monitoring performance, but it is still limited by three issues: insufficient measurement coverage, making it difficult to fully capture fault characteristics with limited measurement points, and a sharp drop in positioning accuracy when data is sparse; high model complexity, with some methods requiring the establishment of complex mathematical relationships, and multiple probability assumptions leading to low computational efficiency; and limited positioning granularity, with existing technologies mostly focusing on fault section identification, lacking the ability to accurately locate fault points, and the communication delay problem has not been fundamentally solved.

[0118] In summary, existing methods are either limited by feature extraction bottlenecks under complex distribution network topologies, or face the dual constraints of high deployment costs and computational complexity, making it difficult to balance the requirements of economy, real-time performance, and accuracy.

[0119] In view of this, an optional embodiment of the present invention provides a method for fault location in distribution networks, which can also be called a multi-frequency signal collaborative injection technology based on zero-sequence current injection. By constructing an active excitation and dynamic sensing mechanism, it fundamentally solves the dual dilemma of signal attenuation and feature annihilation. By stimulating the frequency-varying characteristics of the transition resistance through multi-frequency excitation, it accurately captures the weak transient fingerprints of high-resistance faults. This technological innovation will drive the paradigm shift in fault handling from reactive, blind judgment to proactive, forward-looking analysis, providing core technical support for building a highly reliable new power system and directly responding to the critical need for safe operation of the power grid under corresponding demand objectives. Figure 2 This is a simplified diagram of the zero-order network of the distributed ground parameter system under normal operation, provided by an optional embodiment of the present invention. Figure 3 This is a simplified diagram of a zero-order network after a fault in a distributed ground parameter system provided by an optional embodiment of the present invention, such as... Figure 2 As shown in Figure 3, optional embodiments of the present invention will be described below with reference to the figures:

[0120] Step 1: Principle of the distribution network fault location method based on zero-sequence current injection;

[0121] for Figure 2 The fitting circuit shown, considering line length and its distributed parameters, for a normally functioning distribution network, can also be called a zero-sequence normal network circuit (same as the zero-sequence normal network circuit described above). In this circuit, the segmented admittances (first and second line segment zero-sequence admittances) are "inherent admittances" divided according to the fixed length ratio of the line (such as symmetrically divided 0.5Y0 and 0.5Y0). The parameter values ​​are fixed and only reflect the line's own characteristics to ground. That is, when the admittance variable equation includes initial fixed line parameter terms and intermediate line parameter terms, and the reference line parameters include initial fixed line parameter values ​​and intermediate line parameter values, the zero-sequence normal network circuit corresponding to the distribution network is obtained. The zero-sequence normal network circuit is the zero-sequence network circuit under fault-free conditions. The zero-sequence normal network circuit includes a zero-sequence power supply Iin, a neutral point zero-sequence impedance 3ZN, a first line segment zero-sequence admittance of 0.5Y0, a second line segment zero-sequence admittance of 0.5Y0, a line zero-sequence impedance ZL, one end of the zero-sequence power supply grounded, and the other end connected to the neutral point. One end of the zero-sequence impedance 3ZN is connected in parallel, and the other end of the zero-sequence impedance 3ZN is grounded. The first parallel structure of the zero-sequence power supply and the zero-sequence impedance 3ZN is connected in parallel with one end of the first line segment zero-sequence admittance 0.5Y0. The other end of the first line segment zero-sequence admittance pY0 is grounded. The second parallel structure of the first parallel structure and the first line segment zero-sequence admittance is connected in series with one end of the line zero-sequence impedance ZL. The other end of the line zero-sequence impedance ZL is connected in parallel with one end of the second line segment zero-sequence admittance 0.5Y0. The other end of the second line segment zero-sequence admittance 0.5Y0 is grounded.

[0122] for Figure 3The fitting circuit shown can be called a zero-sequence fault network circuit (same as the zero-sequence fault network circuit mentioned above). The segmented admittances (pY0 and (1-p)Y0) are fault-related admittances dynamically divided according to the fault location coefficient p, where p is an unknown quantity. Therefore, the value of the segmented admittance changes with the fault location and is a key intermediate quantity relating the fault location and electrical characteristics. That is, the zero-sequence fault network circuit is the zero-sequence network circuit under fault conditions. The zero-sequence fault network circuit includes a zero-sequence power supply Iin, a neutral point zero-sequence impedance 3ZN, a first line segmented zero-sequence admittance pY0, a second line segmented zero-sequence admittance, a line zero-sequence impedance PZL, a fault transition resistance 3Rf, one end of the zero-sequence power supply is grounded, and the other end is connected in parallel with one end of the neutral point zero-sequence impedance 3ZN. The other end of the neutral point zero-sequence impedance 3ZN is grounded. The first parallel structure of the zero-sequence power supply and the neutral point zero-sequence impedance 3ZN, and the first line segmented zero-sequence admittance... One end of pY0 is connected in parallel, and the other end of the first line segment zero-sequence admittance pY0 is grounded. The first parallel structure and the second parallel structure of the first line segment zero-sequence admittance are connected in series with one end of the line zero-sequence impedance PZL. The other end of the line zero-sequence impedance PZL is connected in parallel with the third parallel structure. The third parallel structure is a structure formed by connecting one end of the fault transition resistor 3Rf in parallel with one end of the second line segment zero-sequence admittance (1-p)Y0. The other end of the fault transition resistor 3Rf is grounded, and the other end of the second line segment zero-sequence admittance (1-p)Y0 is grounded.

[0123] For a zero-sequence normal network circuit, its zero-sequence admittance to ground is:

[0124] Its zero-sequence admittance with respect to the ground parameter is:

[0125] (1.1)

[0126] in, This is the total admittance of the line. For line admittance, For grounding impedance, The impedance of the arc suppression coil can be used to calculate the total admittance of the line based on the measurement of the zero-sequence voltage and zero-sequence current passing through the power frequency.

[0127] Its specific expression can be expanded as follows:

[0128] (1.2)

[0129] in, System circuit conductivity, For system circuit capacitors, Angular frequency, For ground inductance, For system circuit inductance, To find the equivalent resistance of the arc suppression coil, substituting the above equation into (1.1) yields:

[0130] (1.3)

[0131] Then separately , for:

[0132] (1.4)

[0133] Substituting equation (1.4) into equation (1.3) simplifies to:

[0134] (1.5)

[0135] Separating the real and imaginary parts of the above complex function expression yields:

[0136] (1.6)

[0137] (1.7)

[0138] (1.8)

[0139] In the formula, This is the real part of the total admittance of the line. This is the imaginary part of the total admittance of the line.

[0140] Under normal system operation, the ground admittance and line impedance parameters of the system can be calculated by measuring the ground parameters according to equations (1.4), (1.7), and (1.8). That is, after obtaining the total line admittance, the two unknowns, namely the ground admittance g0 and the system line capacitance C0, can be solved by the two equations with real and imaginary parts.

[0141] For a zero-sequence fault network circuit, considering the line length and its distributed parameters in the case of a ground fault, the zero-sequence admittance during the system fault process is:

[0142] (1.9)

[0143] in, This is the fault location coefficient. , This is the fault transition resistance. Similarly, by expanding the ground admittance, line impedance, and arc suppression coil inductive reactance and substituting them into the above equation, we can obtain:

[0144] (1.10)

[0145] Since the above formula is too complex, let's first... for:

[0146] (1.11)

[0147] For ease of calculation, then define respectively , , , Four algebras:

[0148] (1.12)

[0149] Equation (1.11) can be simplified to:

[0150] (1.13)

[0151] Therefore, equation (1.10) can be simplified to:

[0152] (1.14)

[0153] Then by definition:

[0154] (1.15)

[0155] Equation (1.14) can be further simplified to:

[0156] (1.16)

[0157] Using equation (1.16), the real and imaginary parts of the zero-sequence admittance of the system under fault conditions can be extracted separately:

[0158] (1.17)

[0159] (1.18)

[0160] For the complex nonlinear equation system as shown in equation (1.9), after separating the real and imaginary parts through the above transformation, the complex variables are eliminated. By observing the intermediate variable definitions (1.12) and (1.15), it is easy to see that in the final analytical equation (1.17-1.18), when the distributed ground parameters of the system are known, there are only two unknowns, namely the fault location coefficient p and the fault transition resistance Rf. Since neither of them are first-order terms, the equation system is obviously a nonlinear equation system and cannot be solved directly by combining them.

[0161] Therefore, the following measures will be taken to solve this problem:

[0162] When the system is operating normally, the detailed parameters of the system's ground admittance can be calculated by combining the measurement results of the zero-sequence voltage and zero-sequence current at the power frequency with equations (1.7-1.8). That is, after obtaining the total line admittance, the two unknowns, namely the ground admittance g0 and the system line capacitance C0, can be solved by using the real and imaginary equations.

[0163] When a system fault occurs, in addition to the power frequency zero-sequence phasor, two different frequency zero-sequence current signals are injected using the injection signal method to measure the returned zero-sequence voltage value. This allows us to obtain the system fault zero-sequence admittance values ​​at three frequencies. After taking the real and imaginary parts respectively, we can obtain six sampling points. Then, by combining the known parameters with the parameters obtained under normal conditions, we can apply the least squares sliding window fitting method to equation (1.17-1.18), using the fault transition resistance and fault location as fitting parameters. After solving, we can obtain the fault location p, thereby achieving fault location.

[0164] Step 2: Simulation verification of the method:

[0165] To verify the effectiveness of the proposed fault location method, a typical 10kV distribution network simulation model was built based on the PSCAD platform. The system adopts a radial multi-branch topology, including 5 feeders and 3 distributed power supply access points. The electromagnetic transient characteristics of the 10km long line are accurately characterized using a distributed parametric model, conforming to the mainstream configuration of domestic distribution networks. The fault scenario settings cover key variables: fault location (1-9km in 2km increments), transition resistance (10-2000Ω gradient distribution), and fault type. ≤8% of the 3rd / 5th / 7th harmonics are superimposed in the background to approximate the actual electromagnetic environment. The signal injection scheme is designed to inject 200Hz and 300Hz dual-frequency current signals into the zero-sequence network after a fault, and obtain the zero-sequence voltage response at a sampling rate of 10kHz through a 0.2-level precision voltage transformer at the bus.

[0166] The raw data was analyzed by FFT spectrum to separate the power frequency component from the target heterofrequency signal. The real and imaginary parts of the admittance at each frequency point were extracted by complex admittance calculation to form six sets of independent measurement values. Based on the nonlinear equations constructed by equations (1.15)-(1.16), the fault location p and the transition resistance Rf were solved by least squares fitting using Matlab.

[0167] Table 1 shows the simulation results provided by the optional embodiments of the present invention. The simulation results are shown in Table 1 below. Under the harsh conditions of extreme transition resistance (2000Ω) coupled with a long-distance fault (9km), the method still maintains meter-level positioning accuracy. The data shows that the error is 1.44m (relative error 0.144%) at a position of 1000m with a 10Ω transition resistance, and the error decreases nonlinearly with increasing distance and resistance. The maximum error of this method under the 2000Ω high-resistance condition is still controlled within 0.60m (0.0086%). This strong robustness stems from the decoupling capability of the dual-frequency injection mechanism for the nonlinear frequency-varying characteristics of the transition resistance, effectively suppressing the model mismatch problem under single-frequency measurement.

[0168] Table 1

[0169]

[0170] In an optional embodiment of the present invention, the theoretical analytical expression of the zero-sequence admittance of a typical distribution network system before and after a fault is obtained by measuring the system zero-sequence admittance using the injected signal method, taking into account the distributed parameters of the system and the line impedance, is analyzed theoretically. The real and imaginary parts of the theoretical analytical expression of the zero-sequence admittance are separated by mathematical transformation, and the complex variables are successfully eliminated, resulting in a set of real-variable nonlinear equations. This provides a theoretical basis for analyzing the zero-sequence micro-parameters of the system by frequency domain scanning with injected signals.

[0171] Based on theoretical analysis, this paper first proposes a method to locate faults by repeatedly injecting different-frequency zero-sequence current signals after a fault and measuring the returning zero-sequence voltage, then using the least squares method for analytical fitting. The feasibility of this method is verified through a simple simulation case. Meter-level positioning accuracy can be achieved with a relatively low sampling frequency of the measuring device, demonstrating the correctness of the theoretical analysis. Furthermore, the utilization rate of the injection signal method and the measuring device is improved, enabling high-precision fault location within a section without additional equipment investment costs.

[0172] It should be noted that, for the sake of simplicity, the foregoing method embodiments are all described as a series of actions. However, those skilled in the art should understand that the present invention is not limited to the described order of actions, because according to the present invention, some steps can be performed in other orders or simultaneously. Furthermore, those skilled in the art should also understand that the embodiments described in the specification are preferred embodiments, and the actions and modules involved are not necessarily essential to the present invention.

[0173] Through the above description of the embodiments, those skilled in the art can clearly understand that the methods according to the above embodiments can be implemented by means of software plus necessary general-purpose hardware platforms. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk) and includes several instructions to cause a terminal device (which may be a mobile phone, computer, server, or network device, etc.) to execute the methods of the various embodiments of the present invention.

[0174] Example 2

[0175] According to embodiments of the present invention, an apparatus for implementing the above-described distribution network fault location method is also provided. Figure 4 This is a structural block diagram of a power distribution network fault location device according to an embodiment of the present invention, such as... Figure 4As shown, the device includes: an acquisition module 402, a first determination module 404, a second determination module 406, and a third determination module 408. The device will be described in detail below.

[0176] The acquisition module 402 is used to acquire the zero-sequence fault network circuit corresponding to the distribution network. The zero-sequence fault network circuit is the zero-sequence network circuit under fault conditions. The zero-sequence fault network circuit includes a zero-sequence power supply, a neutral point zero-sequence impedance, a first line segment zero-sequence admittance, a second line segment zero-sequence admittance, a line zero-sequence impedance, and a fault transition resistance. One end of the zero-sequence power supply is grounded, and the other end is connected in parallel with one end of the neutral point zero-sequence impedance, which is also grounded. A first parallel structure of the zero-sequence power supply and the neutral point zero-sequence impedance is connected in parallel with one end of the first line segment zero-sequence admittance, which is also grounded. A second parallel structure of the first parallel structure and the first line segment zero-sequence admittance is connected in series with one end of the line zero-sequence impedance. The other end of the line zero-sequence impedance is connected in parallel with a third parallel structure, where one end of the fault transition resistance is connected to the second line segment zero-sequence admittance. The structure is formed by parallel connection at one end, with the other end of the fault transition resistor grounded, and the other end of the second line segment zero-sequence admittance grounded; the first determining module 404, connected to the above-mentioned acquisition module 402, is used to inject zero-sequence current signals at multiple frequencies into the zero-sequence power supply of the zero-sequence fault network circuit, and determine the return zero-sequence voltage corresponding to the multiple frequencies respectively, wherein the multiple frequencies include a predetermined power frequency, a first frequency, and a second frequency, the first frequency and the second frequency are different, and the return zero-sequence voltage is the zero-sequence voltage returned by the second parallel structure; the second determining module 406, connected to the above-mentioned first determining module 404, is used to determine the fault zero-sequence admittance corresponding to the multiple frequencies respectively based on the zero-sequence current signals and the return zero-sequence voltage corresponding to the multiple frequencies; the third determining module 408, connected to the above, is used to determine the target fault location of the distribution network based on the reference line parameters corresponding to the distribution network and the multiple fault zero-sequence admittances.

[0177] It should be noted that the above-mentioned acquisition module 402, first determination module 404, second determination module 406 and third determination module 408 correspond to steps S102 to S108 in the method for locating faults in a power distribution network. The multiple modules and the corresponding steps are the same in terms of implementation examples and application scenarios, but are not limited to the content disclosed in the above embodiment 1.

[0178] Example 3

[0179] According to another aspect of the present invention, an electronic device is also provided, comprising: a processor; and a memory for storing processor-executable instructions, wherein the processor is configured to execute instructions to implement the power distribution network fault location method described above.

[0180] Example 4

[0181] According to another aspect of the present invention, a computer-readable storage medium is also provided, which, when the instructions in the computer-readable storage medium are executed by a processor of an electronic device, enables the electronic device to perform any of the above-described power distribution network fault location methods.

[0182] The sequence numbers of the above embodiments of the present invention are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0183] In the above embodiments of the present invention, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0184] In the several embodiments provided in this application, it should be understood that the disclosed technical content can be implemented in other ways. The device embodiments described above are merely illustrative; for example, the division of units can be a logical functional division, and in actual implementation, there may be other division methods. For instance, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the displayed or discussed mutual coupling, direct coupling, or communication connection may be through some interfaces; the indirect coupling or communication connection between units or modules may be electrical or other forms.

[0185] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0186] Furthermore, the functional units in the various embodiments of the present invention can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0187] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, read-only memory (ROM), random access memory (RAM), portable hard drives, magnetic disks, or optical disks.

[0188] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for locating faults in a power distribution network, characterized in that, include: Obtain the zero-sequence fault network circuit corresponding to the distribution network, wherein the zero-sequence fault network circuit is a zero-sequence network circuit under fault conditions, the zero-sequence fault network circuit includes a zero-sequence power supply, a neutral point zero-sequence impedance, a first line segment zero-sequence admittance, a second line segment zero-sequence admittance, a line zero-sequence impedance, and a fault transition resistor. One end of the zero-sequence power supply is grounded, and the other end is connected in parallel with one end of the neutral point zero-sequence impedance. The other end of the neutral point zero-sequence impedance is grounded. The first parallel structure of the zero-sequence power supply and the neutral point zero-sequence impedance is connected in parallel with one end of the first line segment zero-sequence admittance. The other end of the first line segment zero-sequence admittance is grounded. The second parallel structure of the first parallel structure and the first line segment zero-sequence admittance is connected in series with one end of the line zero-sequence impedance. The other end of the line zero-sequence impedance is connected in parallel with a third parallel structure. The third parallel structure is a structure formed by connecting one end of the fault transition resistor and one end of the second line segment zero-sequence admittance in parallel. The other end of the fault transition resistor is grounded, and the other end of the second line segment zero-sequence admittance is grounded. Injecting zero-sequence current signals at multiple frequencies into the zero-sequence power supply of the zero-sequence fault network circuit, and determining the return zero-sequence voltage corresponding to each of the multiple frequencies, wherein the multiple frequencies include a predetermined power frequency, a first frequency, and a second frequency, the first frequency being different from the second frequency, and the return zero-sequence voltage being the zero-sequence voltage returned by the second parallel structure; Based on the zero-sequence current signal and the return zero-sequence voltage corresponding to the plurality of frequencies, determine the fault zero-sequence admittance corresponding to each of the plurality of frequencies; Based on the reference line parameters and multiple fault zero-sequence admittances corresponding to the distribution network, the target fault location of the distribution network is determined; The determination of the target fault location of the distribution network based on the reference line parameters and multiple fault zero-sequence admittances includes: determining the real and imaginary eigenvalues ​​corresponding to the multiple fault zero-sequence admittances; retrieving the admittance variable equation corresponding to the distribution network, wherein the admittance variable equation includes a real variable equation and an imaginary variable equation, the real variable equation being an equation between the real eigenvalues ​​and the target variable equation, and the imaginary variable equation being an equation between the imaginary eigenvalues ​​and the target variable equation, the target variable equation including a fault location coefficient and a fault transition resistance; solving for the target fault coefficient value corresponding to the fault location coefficient based on the reference line parameters, the real and imaginary eigenvalues ​​corresponding to the multiple fault zero-sequence admittances, and the admittance variable equation; and determining the target fault location based on the target fault coefficient value. The determination of the target fault location based on the target fault coefficient value includes: determining the total line length and the position of the zero-sequence current injection end; determining the product of the total line length and the target fault coefficient value to obtain the target length; and taking the position of the zero-sequence current injection end as the starting point and extending the target length towards the end of the line as the target fault location.

2. The method according to claim 1, characterized in that, Based on the reference line parameters corresponding to the distribution network, the real and imaginary eigenvalues ​​corresponding to the plurality of fault zero-sequence admittances, and the admittance variable equation, the target fault coefficient value corresponding to the fault location coefficient term is solved, including: The real part impedance parameter corresponding to the reference line parameter and the real part eigenvalues ​​corresponding to the multiple fault zero-sequence admittances are respectively input into the real part variable equation to obtain the target real part equations corresponding to the multiple frequencies respectively. The imaginary impedance parameters corresponding to the reference line parameters and the imaginary characteristic values ​​corresponding to the multiple fault zero-sequence admittances are respectively input into the imaginary variable equation to obtain the target imaginary equations corresponding to the multiple frequencies. By fitting multiple target real part equations and multiple target imaginary part equations using the least squares sliding window method, the variable values ​​corresponding to the target variable terms are obtained, wherein the variable values ​​include the target fault coefficient values ​​corresponding to the fault location coefficient terms.

3. The method according to claim 1, characterized in that, Before solving for the target fault coefficient value corresponding to the fault location coefficient term based on the reference line parameters corresponding to the distribution network, the real and imaginary eigenvalues ​​corresponding to the plurality of fault zero-sequence admittances, and the admittance variable equation, the following steps are also included: The admittance variable equation includes initial fixed line parameter terms and intermediate line parameter terms. When the reference line parameters include initial fixed line parameter values ​​and intermediate line parameter values, a zero-sequence normal network circuit corresponding to the distribution network is obtained. The zero-sequence normal network circuit is a zero-sequence network circuit in a fault-free state. The zero-sequence normal network circuit includes a zero-sequence power supply, a neutral point zero-sequence impedance, a first line segment zero-sequence admittance, a second line segment zero-sequence admittance, and a line zero-sequence impedance. One end of the zero-sequence power supply is grounded, and the other end is connected in parallel with one end of the neutral point zero-sequence impedance. The other end of the neutral point zero-sequence impedance is grounded. A first parallel structure of the zero-sequence power supply and the neutral point zero-sequence impedance is connected in parallel with one end of the first line segment zero-sequence admittance. The other end of the first line segment zero-sequence admittance is grounded. A second parallel structure of the first parallel structure and the first line segment zero-sequence admittance is connected in series with one end of the line zero-sequence impedance. The other end of the line zero-sequence impedance is connected in parallel with one end of the second line segment zero-sequence admittance. The other end of the second line segment zero-sequence admittance is grounded. Inject the zero-sequence current signal at the predetermined power frequency into the zero-sequence power supply of the zero-sequence normal network circuit, and determine the return zero-sequence voltage corresponding to the predetermined power frequency; Based on the initial fixed line parameter values, the zero-sequence current signal corresponding to the predetermined power frequency, and the returned zero-sequence voltage, the intermediate line parameter values ​​are obtained.

4. The method according to claim 1, characterized in that, The equation for the real part variable is expressed by the following formula: ； The equation for the imaginary part variable is expressed by the following formula: ； in, This is the real part characteristic term corresponding to the zero-sequence admittance term of the fault. This is the imaginary characteristic term corresponding to the zero-sequence admittance term of the fault. For the fault location coefficient term, For the line-to-ground conductivity term, This refers to the line-to-ground capacitance. This refers to the angular frequency term of the zero-sequence current signal at the corresponding frequency. Represents the first algebraic terms. Represents second-generation terms. Represents third-generation terms. Represents fourth-generation terms. , Inductance to ground; The first algebraic term representation ; Second algebraic term representation ; The third-generation numerical representation ; The fourth-generation numerical representation ; Where R0 represents the zero-sequence resistance term of the line, and L0 represents the zero-sequence inductance term of the line. This is the fault transition resistance term.

5. A power distribution network fault location system, characterized in that, include: A zero-sequence fault network circuit and a controller are provided. The zero-sequence fault network circuit is a zero-sequence network circuit operating under fault conditions. The zero-sequence fault network circuit includes a zero-sequence power supply, a neutral point zero-sequence impedance, a first segmented zero-sequence admittance, a second segmented zero-sequence admittance, a line zero-sequence impedance, and a fault transition resistor. One end of the zero-sequence power supply is grounded, and the other end is connected in parallel with one end of the neutral point zero-sequence impedance. The other end of the neutral point zero-sequence impedance is grounded. A first parallel structure of the zero-sequence power supply and the neutral point zero-sequence impedance is connected in parallel with one end of the first segmented zero-sequence admittance. The other end of the first segmented zero-sequence admittance is grounded. A second parallel structure of the first parallel structure and the first segmented zero-sequence admittance is connected in series with one end of the line zero-sequence impedance. The other end of the line zero-sequence impedance is connected in parallel with a third parallel structure. The third parallel structure is formed by connecting one end of the fault transition resistor and one end of the second segmented zero-sequence admittance in parallel. The other end of the fault transition resistor and the other end of the second segmented zero-sequence admittance are grounded. The controller is used to acquire the zero-sequence fault network circuit, inject zero-sequence current signals at multiple frequencies into the zero-sequence power supply of the zero-sequence fault network circuit, and determine the return zero-sequence voltage corresponding to each of the multiple frequencies. The multiple frequencies include a predetermined power frequency, a first frequency, and a second frequency, where the first frequency is different from the second frequency. The return zero-sequence voltage is the zero-sequence voltage returned by the second parallel structure. Based on the zero-sequence current signals and the return zero-sequence voltage corresponding to the multiple frequencies, the controller determines the fault zero-sequence admittance corresponding to each of the multiple frequencies. Based on the reference line parameters corresponding to the distribution network and the multiple fault zero-sequence admittances, the controller determines the target fault location of the distribution network. The determination of the target fault location of the distribution network based on the reference line parameters and multiple fault zero-sequence admittances includes: determining the real and imaginary eigenvalues ​​corresponding to the multiple fault zero-sequence admittances; retrieving the admittance variable equation corresponding to the distribution network, wherein the admittance variable equation includes a real variable equation and an imaginary variable equation, the real variable equation being an equation between the real eigenvalues ​​and the target variable equation, and the imaginary variable equation being an equation between the imaginary eigenvalues ​​and the target variable equation, the target variable equation including a fault location coefficient and a fault transition resistance; solving for the target fault coefficient value corresponding to the fault location coefficient based on the reference line parameters, the real and imaginary eigenvalues ​​corresponding to the multiple fault zero-sequence admittances, and the admittance variable equation; and determining the target fault location based on the target fault coefficient value. The determination of the target fault location based on the target fault coefficient value includes: determining the total line length and the position of the zero-sequence current injection end; determining the product of the total line length and the target fault coefficient value to obtain the target length; and taking the position of the zero-sequence current injection end as the starting point and extending the target length towards the end of the line as the target fault location.

6. A power distribution network fault location device, characterized in that, include: An acquisition module is used to acquire the zero-sequence fault network circuit corresponding to the distribution network. The zero-sequence fault network circuit is a zero-sequence network circuit under fault conditions. The zero-sequence fault network circuit includes a zero-sequence power supply, a neutral point zero-sequence impedance, a first line segment zero-sequence admittance, a second line segment zero-sequence admittance, a line zero-sequence impedance, and a fault transition resistor. One end of the zero-sequence power supply is grounded, and the other end is connected in parallel with one end of the neutral point zero-sequence impedance. The other end of the neutral point zero-sequence impedance is grounded. A first parallel structure of the zero-sequence power supply and the neutral point zero-sequence impedance is connected in parallel with one end of the first line segment zero-sequence admittance. The other end of the first line segment zero-sequence admittance is grounded. A second parallel structure of the first parallel structure and the first line segment zero-sequence admittance is connected in series with one end of the line zero-sequence impedance. The other end of the line zero-sequence impedance is connected in parallel with a third parallel structure. The third parallel structure is formed by connecting one end of the fault transition resistor and one end of the second line segment zero-sequence admittance in parallel. The other end of the fault transition resistor is grounded, and the other end of the second line segment zero-sequence admittance is grounded. The first determining module is used to inject zero-sequence current signals at multiple frequencies into the zero-sequence power supply of the zero-sequence fault network circuit, and determine the return zero-sequence voltage corresponding to the multiple frequencies respectively. The multiple frequencies include a predetermined power frequency, a first frequency, and a second frequency. The first frequency is different from the second frequency. The return zero-sequence voltage is the zero-sequence voltage returned by the second parallel structure. The second determining module is used to determine the fault zero-sequence admittance corresponding to each of the multiple frequencies based on the zero-sequence current signal and the return zero-sequence voltage corresponding to the multiple frequencies. The third determining module is used to determine the target fault location of the distribution network based on the reference line parameters corresponding to the distribution network and multiple fault zero-sequence admittances. The third determining module is further configured to: determine the real and imaginary eigenvalues ​​corresponding to the multiple fault zero-sequence admittances; retrieve the admittance variable equation corresponding to the distribution network, wherein the admittance variable equation includes a real variable equation and an imaginary variable equation, the real variable equation being an equation between the real eigenvalues ​​and the target variable equation, and the imaginary variable equation being an equation between the imaginary eigenvalues ​​and the target variable equation, the target variable equation including a fault location coefficient and a fault transition resistance; solve for the target fault coefficient value corresponding to the fault location coefficient based on the reference line parameters corresponding to the distribution network, the real and imaginary eigenvalues ​​corresponding to the multiple fault zero-sequence admittances, and the admittance variable equation; and determine the target fault location based on the target fault coefficient value. The third determining module is further configured to determine the total length of the line and the position of the zero-sequence current injection end; determine the product of the total length of the line and the target fault coefficient value to obtain the target length; and take the position of the zero-sequence current injection end as the starting point and extend the target length towards the end of the line as the target fault position.

7. An electronic device, characterized in that, include: processor; Memory used to store the processor's executable instructions; The processor is configured to execute the instructions to implement the power distribution network fault location method as described in any one of claims 1 to 4.

8. A computer-readable storage medium, characterized in that, When the instructions in the computer-readable storage medium are executed by the processor of the electronic device, the electronic device is able to perform the power distribution network fault location method as described in any one of claims 1 to 4.

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