A four-quadrant adaptive intelligent current protection method and system for a power distribution network

Abstract

The application discloses a power distribution network four-quadrant adaptive intelligent current protection method and system, which comprises the following steps: determining a phase angle difference according to fault current data and fault voltage data; determining a fault type and a target quadrant of the fault type in the four quadrants of the power distribution network through the phase angle difference, wherein the fault type comprises a resistive and inductive load user fault, a non-clean energy power generation user fault, a clean energy power generation user fault, a resistive and capacitive load user fault, and a line fault after a power flow direction is changed after an operation mode is changed; overcurrent protection is adopted in the case that the fault current data is greater than a current setting value; and overcurrent protection is performed on the line fault with the same point fault after the power flow direction is changed after the operation mode is changed due to different fault currents in different operation modes. The application can perfectly solve the problem that different fault currents inside and outside the demarcation point of various power generation users cannot reliably act, and effectively improves the speed and selectivity of the fault protection of the power distribution network.

Description

TECHNICAL FIELD

[0001] The embodiment of the present application relates to the technical field of power distribution network protection, and particularly relates to a four-quadrant adaptive intelligent current protection method and system for a power distribution network. BACKGROUND

[0002] With the continuous development of society, the power system plays an important role in our daily life, which not only relates to the user's power experience, but also has a profound impact on economic and social development. The safety protection of the power distribution network is the premise of ensuring the stability of power supply, and unstable power supply will lead to the user's power demand being unable to be met, and even cause adverse effects on the normal production and life of the masses. Therefore, it is of great significance to protect the safety of the power distribution network.

[0003] At present, the safety protection of the power distribution network usually adopts overcurrent protection, which is to protect the equipment of enterprises from being damaged by cutting off the circuit or issuing an alarm signal when the current exceeds the predetermined maximum value. However, when the overcurrent protection is in the current fast breaking and time-limited current fast breaking protection, due to the different fault current limits of different types of enterprise operating conditions, the current limit is fixed, and it is unable to adaptively adjust the maximum current limit for different types of enterprise operating condition changes, resulting in that when the power distribution network fails, the overcurrent protection device cannot quickly lock and cut off the fault current, causing the equipment of the enterprise to be damaged due to excessive current, and when the power grid operating mode changes, the power flow changes, and the same point fault current value is different, causing unnecessary expansion of the fault power outage range, thereby affecting the stability of the power system.

[0004] Therefore, there is an urgent need for a method to solve the above problems. SUMMARY

[0005] The embodiment of the present application provides a four-quadrant adaptive intelligent current protection method and system for a power distribution network, which is used for improving the stability of the power system.

[0006] To achieve the above purpose, the embodiments of the present application adopt the following technical solutions:

[0007] In a first aspect, a four-quadrant adaptive intelligent current protection method for a power distribution network is provided, comprising:

[0008] obtaining fault current data and fault voltage data of a target line in a power distribution network at a fault moment;

[0009] determining a phase angle difference of the target line according to the fault current data and the fault voltage data;

[0010] determining a fault type according to the fault current phase angle difference, and determining a target quadrant of the fault type in four quadrants of the power distribution network, the fault type including a resistive and inductive load user fault, a non-clean energy generation user fault, a clean energy generation user, a resistive and capacitive load user fault, and a line fault after a power flow direction is changed after a change in operation mode;

[0011] determining whether the fault current data is greater than a current fixed value corresponding to the target quadrant, and performing overcurrent protection on the target user fault and the line fault after the power flow direction is changed after the change in operation mode due to different fault currents in different operation modes in a case where the fault current data is greater than the current fixed value.

[0012] In a possible implementation of the first aspect, in the four quadrants of the power distribution network, the resistive and inductive load user is located in a first quadrant of the four quadrants, the non-clean energy generation user is located in a second quadrant of the four quadrants, the clean energy generation user is located in a third quadrant of the four quadrants, and the resistive and capacitive load user is located in a fourth quadrant of the four quadrants, the resistive and inductive load user is configured to input active power and input reactive power to the power distribution network, the non-clean energy generation user is configured to output active power and input reactive power to the power distribution network, the clean energy generation user is configured to output active power and output reactive power to the power distribution network, and the resistive and capacitive load user is configured to input active power and output reactive power to the power distribution network.

[0013] Before the step of obtaining the fault current data and the fault voltage data of the target line in the power distribution network at the fault moment, the method comprises:

[0014] real-time obtaining current data and voltage data of the power distribution network, and determining whether a fault exists in the power distribution network according to the current data and the voltage data;

[0015] In a case where the fault exists in the power distribution network, performing the step of obtaining the fault current data and the fault voltage data of the target line in the power distribution network at the fault moment.

[0016] In a possible implementation of the first aspect, the determining the phase angle difference of the target line according to the fault current data and the fault voltage data comprises:

[0017] obtaining an instantaneous power value of the power distribution network at the fault moment through the fault current data and the fault voltage data, wherein the instantaneous power value includes reactive power and active power;

[0018] determining input values and output values of the reactive power and the active power based on the reactive power and the active power;

[0019] calculate a power factor of the target line at the fault moment through the input value and the output value of the reactive power, the input value and the output value of the active power;

[0020] adopt a preset phase angle formula to calculate a phase angle difference of the target line according to the power factor.

[0021] In a possible implementation manner of the first aspect, the determining whether the power distribution network has the fault according to the current data and the voltage data comprises:

[0022] obtaining historical sample current data and historical sample voltage data;

[0023] constructing a historical current spectrum graph and a historical voltage spectrum graph according to the historical sample current data and the historical sample voltage data;

[0024] constructing a real-time current spectrum graph and a real-time voltage spectrum graph according to the current data and the voltage data obtained in real time;

[0025] extracting a historical current feature vector of the historical current spectrum graph and a historical voltage feature vector of the historical voltage spectrum graph;

[0026] extracting a real-time current feature vector of the real-time current spectrum graph and a real-time voltage feature vector of the real-time voltage spectrum graph;

[0027] calculating a first similarity between the historical current feature vector and the real-time current feature vector;

[0028] calculating a second similarity between the historical voltage feature vector and the real-time voltage feature vector;

[0029] if any one of the first similarity and the second similarity is less than a preset similarity threshold, determining that the power distribution network has the fault.

[0030] In a possible implementation manner of the first aspect, the real-time current feature vector comprises a current amplitude and a current phase, the real-time voltage feature vector comprises a voltage amplitude and a voltage phase, and after the real-time current spectrum graph and the real-time voltage spectrum graph are constructed according to the current data and the voltage data obtained in real time, the method further comprises:

[0031] judging whether the real-time current spectrum graph has signal interference through the current amplitude and the current phase of the real-time current spectrum graph;

[0032] if the current amplitude in the real-time current spectrum graph is greater than a preset reference amplitude and an offset value of the current phase is greater than a preset phase threshold, determining that the real-time current spectrum graph has signal interference.

[0033] correcting the real-time current spectrogram by using a preset spectrogram correction method;

[0034] determining whether the real-time voltage spectrogram has signal interference by using the voltage amplitude and the voltage phase of the real-time voltage spectrogram;

[0035] if the voltage amplitude in the real-time voltage spectrogram is greater than a preset reference amplitude and the offset value of the voltage phase is greater than a preset phase threshold, it is determined that the real-time voltage spectrogram has signal interference;

[0036] correcting the real-time voltage spectrogram by using a preset spectrogram correction step.

[0037] In a possible implementation manner of the first aspect, the method further includes:

[0038] calculating the complex power of the fault line by using the fault current data and the fault voltage data;

[0039] determining the power range in which the complex power is located;

[0040] determining the preliminary fault type and the preliminary fault severity by using the power range;

[0041] dividing the target line based on the preliminary fault type and the preliminary fault severity to obtain a plurality of sub-lines;

[0042] determining the fault sub-line and the fault position in the fault sub-line by using a preset fault locating technology for each of the sub-lines.

[0043] In a possible implementation manner of the first aspect, before the fault current data of the target line in the power distribution network at the fault moment is acquired, the method further includes:

[0044] acquiring the terminal node and the branch node in the power distribution line of the target phase, wherein the branch node is located at the connection between the branch line of the power distribution line and the main line of the power distribution line, and the terminal node is located at the connection between the branch line of the power distribution line and the load device;

[0045] constructing the terminal node and the branch node as a section of the power distribution line, wherein the section of the power distribution line includes a main line section and a branch line section, the line between the terminal node and the branch node is the branch line section, and the line between the branch node and the adjacent branch node is the main line section;

[0046] determine an influence degree of each of the sections, and determine at least one target line according to the influence degree;

[0047] determining the fault type according to the fault current phase angle difference, and determining a target quadrant of the fault type in four quadrants of the power distribution network, comprises:

[0048] determining a preset angle range in which the phase angle difference is located, and determining a user fault type corresponding to the target line through the preset angle range;

[0049] determining a target quadrant corresponding to the user type in the four quadrants of the power distribution network according to the user fault type.

[0050] In a possible implementation manner of the first aspect, the determining the influence degree of each of the sections, and determining at least one target line according to the influence degree, comprises:

[0051] acquiring transmission power of each of the sections at the fault moment;

[0052] comparing each of the transmission power with a preset reference power, marking the sections exceeding the preset reference power to obtain reference power exceeding sections;

[0053] comparing the transmission power of each of the sections at the fault moment with the preset reference power, marking the sections not exceeding the preset reference power to obtain reference power not exceeding sections;

[0054] determining a difference value between each of the reference power exceeding sections and the preset reference power to obtain a first power number set;

[0055] determining a difference value between each of the reference power not exceeding sections and the preset reference power to obtain a second power number set;

[0056] constructing a matrix by using the first power number set and the second power number set, wherein a row vector in the matrix represents each of the sections, and a column vector in the matrix is composed of the first power number set and the second power number set;

[0057] determining the influence degree of each of the sections based on a preset risk assessment matrix;

[0058] multiplying the influence degree of each of the sections with a power value of each of the corresponding sections in the matrix to obtain an influence degree matrix;

[0059] marking the sections exceeding a preset threshold value in the influence degree matrix, and taking the sections exceeding the preset threshold value as target lines.

[0060] In a second aspect, the present application provides a machine readable storage medium having instructions stored thereon for causing a machine to perform the power distribution network four-quadrant adaptive intelligent current protection method.

[0061] In a third aspect, the present application provides a power distribution network four-quadrant adaptive intelligent current protection system, comprising:

[0062] a memory configured to store instructions; and

[0063] a processor configured to call the instructions from the memory and enable the power distribution network four-quadrant adaptive intelligent current protection method described above when executing the instructions.

[0064] Through the above technical solution, by acquiring the current data and voltage data of the power distribution network and determining whether there is a fault in the power distribution network, the fault of the power distribution network can be effectively monitored, and abnormal conditions in the power distribution network can be found in time, so that measures can be taken in advance to prevent the occurrence of faults. In the case of a fault in the power distribution network, the fault location can be determined, the fault location of the power distribution network can be accurately obtained in time, the troubleshooting time of the power distribution network is reduced, and the economic loss caused by power failure is reduced. Among them, the four quadrants of the power distribution network are divided based on user types, by determining the fault location, the target user affected by the fault can be quickly identified, the target user is determined in the target quadrant of the power distribution network, the resource scheduling and allocation of the power distribution network can be optimized, and the maintenance efficiency of the power distribution network can be improved. The current setting value of the target quadrant, when the fault current is greater than the current setting value of the target quadrant, overcurrent protection is taken for the target user in the target quadrant, the fault equipment of the target user is isolated in time through the flow protection, which can prevent the fault from spreading in the power grid, reduce the influence of the fault on the overall operation of the power grid, and ensure the stability of the power system operation.

[0065] Other features and advantages of the embodiments of the present application will be described in detail in the following specific embodiments. BRIEF DESCRIPTION OF DRAWINGS

[0066] Figure 1 A flowchart of a power distribution network four-quadrant adaptive intelligent current protection method provided by the embodiments of the present application is shown in the figure;

[0067] Figure 2 A schematic diagram of a power distribution network four-quadrant provided by the embodiments of the present application is shown in the figure;

[0068] Figure 3 A structural schematic diagram of a power distribution network main line section and branch line section provided by the embodiments of the present application is shown in the figure. DETAILED DESCRIPTION

[0069] To make the objects, technical solutions and advantages of the embodiments of the present application clearer, the following will be combined with the accompanying drawings for the embodiments to briefly describe the technical solutions in the embodiments of the present application in a clear and complete manner. It should be understood that the specific implementation manners described herein are only used to explain and illustrate the embodiments of the present application and should not be used to limit the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative effort fall within the scope of protection of the present application.

[0070] It should be noted that if the embodiments of the present application involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative positional relationship, motion condition, etc. between components in a certain specific posture (as shown in the drawings), and if the specific posture changes, the directional indications also change accordingly.

[0071] In addition, if the embodiments of the present application involve descriptions such as “first”, “second”, etc., the descriptions of “first”, “second”, etc. are only for description purposes and should not be understood as indicating or implying the relative importance of the indicated technical features or implicitly indicating the number of the indicated technical features. Therefore, the features limited by “first”, “second” can explicitly or implicitly include at least one of the features. In addition, the technical solutions of the various embodiments can be combined with each other, but it must be based on the fact that a person of ordinary skill in the art can realize it, and when the combination of technical solutions contradicts each other or cannot be realized, it should be considered that the combination of technical solutions does not exist and is not within the scope of protection claimed by the present application.

[0072] Figure 1 A flowchart of a power distribution network four-quadrant adaptive intelligent current protection method according to the embodiments of the present application is schematically shown. As shown in Figure 1 The embodiments of the present application provide a power distribution network four-quadrant adaptive intelligent current protection method, which can include the following steps.

[0073] S110, obtaining fault current data and fault voltage data of a target line in a power distribution network at a fault moment;

[0074] S120, determining a phase angle difference of the target line according to the fault current data and the fault voltage data;

[0075] S130, determining a fault type and a target quadrant of the fault type in four quadrants of the power distribution network according to the fault current phase angle difference, the fault type including a resistive and inductive load user fault, a non-clean energy power generation user fault, a clean energy power generation user, a resistive and capacitive load user fault, and a line fault after a power flow direction changes after an operation mode changes;

[0076] S140, determining whether the fault current data is greater than the current fixed value corresponding to the target quadrant, and in the case that the fault current data is greater than the current fixed value, overcurrent protection is performed on the target user fault, and overcurrent protection is performed on the line fault with the same point fault where the power flow direction changes after the operation mode changes due to the different fault currents under different operation modes.

[0077] The fault current data and the fault voltage data of the target line in the power distribution network at the fault moment can be obtained through the smart meter and the sensor, and the sensor can be a current sensor and a voltage sensor. Through the data of the smart meter and the sensor, the operating state of the power distribution line can be monitored in real time, and parameters such as current, voltage, power factor, fault current and fault voltage can be monitored in real time.

[0078] After obtaining the fault current data and the fault voltage data of the target line in the power distribution network at the fault moment, the phase angle difference of the target line is determined according to the fault current data and the fault voltage data. Specifically, first, the instantaneous power value of the power distribution network at the fault moment is obtained through the fault current data and the fault voltage data, wherein the instantaneous power value includes reactive power and active power. The instantaneous power value at the fault moment of the power distribution network can be obtained through measuring devices such as current transformers and voltage transformers, and appropriate signal processing such as filtering and amplifying signals can be required to improve the accuracy of measurement. The reactive power refers to the electric power required to establish a magnetic field when the inductance, capacitance and other components in the electrical equipment are working. It is a form of electric energy, but it cannot do work and cannot be consumed. The active power refers to the electric power required to keep the equipment running, that is, the electric power that converts electric energy into other forms of energy. Subsequently, based on the reactive power and the active power, the input value and the output value of the reactive power, and the input value and the output value of the active power are determined; and the power factor at the fault moment is calculated through the formula of the active power or the formula of the reactive power, and the phase angle difference of the target line is calculated according to the preset phase angle formula and the power factor.

[0079] Figure 2 A structure diagram of a four-quadrant power distribution network according to an embodiment of the present application is schematically shown, as shown in the figure: the first quadrant is a resistive and inductive load user, the second quadrant is a non-clean energy power generation user, the third quadrant is a clean energy power generation user, and the fourth quadrant is a resistive and capacitive load user.

[0080] After determining the phase angle difference of the target line, the fault type is determined based on the fault current phase angle difference. In this embodiment, the fault types include faults of resistive-inductive load users, faults of non-clean energy generation users, faults of clean energy generation users, faults of resistive-capacitive load users, and line faults caused by changes in power flow direction due to changes in operating mode. Phase angle difference refers to the displacement difference between two waves with the same frequency but different phases. In alternating current, it specifically refers to the phase difference between two currents or voltages with the same frequency. Line faults caused by changes in power flow direction due to changes in operating mode refer to situations where changes in the power system's operating mode, such as power source switching or load transfer, affect the power distribution and power flow direction in the system. For example, when a power source is disconnected, the power originally provided by that source will be redistributed, which may cause changes in the power flow direction of other lines. In this embodiment, the four quadrants of the distribution network are based on user type. User types include resistive-inductive load users, non-clean energy generation users, clean energy generation users, and resistive-capacitive load users. Resistive-inductive load users are located in the first quadrant of the four quadrant, which represents input active power and input reactive power. These users are resistive-inductive loads and need to obtain electrical energy and reactive power from the grid. Non-clean energy generation users are located in the second quadrant of the four quadrant, which represents output active power but input reactive power. They feed active power back to the grid but still need to obtain reactive power from the grid. Clean energy generation users are located in the third quadrant of the four quadrant, which represents output active power and output reactive power. They feed electrical energy and reactive power back to the grid. Resistive-capacitive load users are located in the fourth quadrant of the four quadrant, which represents input active power but output reactive power. These users are resistive-capacitive loads and obtain active power from the grid but feed reactive power back to the grid. The fourth quadrant represents input active power but output reactive power, where the user is a resistive-capacitive load that receives active power from the grid but feeds reactive power back to it. The fault type is determined based on the phase angle difference of the fault current, as well as the target quadrant within the four quadrants of the distribution network. This means comparing the fault current phase angle difference with known fault type characteristics to derive the fault type. For example, in a symmetrical fault, the phase angle difference between the three-phase voltage and current is 120°, with the positive-sequence components having the same phase angle and the negative-sequence component having a 0° phase angle. In an asymmetrical fault, the phase angle difference between the three-phase voltage and current is not 120°, and the positive-sequence and negative-sequence components have different phase angles. Common asymmetrical fault types include single-phase grounding faults and two-phase short-circuit faults. An asymmetrical fault refers to a fault where the three-phase voltage and current are asymmetrical in amplitude or phase. This is because asymmetrical faults cause the magnitude and phase of the three-phase currents to no longer be equal or differ by a fixed angle, thus the phase angle difference exhibits an asymmetrical distribution.If the phase angle difference meets the characteristics of a symmetrical fault, such as a three-phase phase angle difference of 120°, and the positive sequence component phase angle is consistent and the negative sequence component phase angle is 0°, it is determined to be a symmetrical fault, and if the phase angle difference does not meet the characteristics of a symmetrical fault, it is further analyzed whether it meets the characteristics of an asymmetrical fault.

[0081] After determining the fault type, the fault type is determined, and the target quadrant of the fault type in the four-quadrant power distribution network is determined. Specifically, a preset angle range of the phase angle difference is determined, and the user type corresponding to the target line is determined through the preset angle range. After obtaining the user type, the target quadrant corresponding to the user type in the four-quadrant power distribution network is determined. For example, when the phase difference is between 0° and 90° and the power factor is greater than 0, the target user is in the first quadrant; when the phase difference is between -90° and 0° and the power factor is less than 0, it means that active power is sent but reactive power is absorbed, and the target user is in the second quadrant; when the phase difference is between -90° and -180° and the power factor is less than 0, it means that active power and reactive power are sent, and the target user is in the third quadrant; when the phase difference is between 0° and 90° and the power factor is greater than 0, but the current direction is opposite to the voltage direction, the target user is in the fourth quadrant.

[0082] It is determined whether the fault current data is greater than the current setting value corresponding to the target quadrant, and overcurrent protection is performed on the target user fault when the fault current data is greater than the current setting value, and overcurrent protection is performed on the line fault caused by the change of the fault current under different operating modes. That is, whether the fault current data is greater than the current setting value corresponding to the target quadrant, and overcurrent protection is performed on the target user in the target quadrant when the fault current data is greater than the current setting value. Overcurrent protection refers to when the current flowing through the protected element exceeds the preset value, the protection device is activated to ensure the selectivity of the action, so that the circuit breaker trips or an alarm signal is sent, thereby protecting the circuit and electrical equipment from damage. That is, when the power distribution line fails due to reasons such as short circuit, overload, etc., the current value is abnormal, it is determined whether the abnormal current value is greater than the maximum current preset value in the target quadrant, and when the abnormal current value is greater than the maximum current preset value, the current protection device acts, that is, when the current flowing through the protected element exceeds the preset value, the protection device is activated to cut off or limit the current, thereby protecting the equipment and circuit from damage.

[0083] By the technical solution, the current data and voltage data of the power distribution network are acquired, and it is determined whether the power distribution network has a fault, so that the fault of the power distribution network can be effectively monitored, and abnormal conditions in the power distribution network can be found in time, so that measures are taken in advance to prevent the occurrence of the fault. In the case that the power distribution network has a fault, the fault position is determined, so that the fault position of the power distribution network can be accurately acquired in time, the troubleshooting time of the power distribution network is reduced, and economic losses caused by power failure are reduced. The four quadrants of the power distribution network are divided based on user types, by determining the fault position, it can be quickly identified that the target user is affected by the fault, and the target quadrant in which the target user is located in the four quadrants of the power distribution network is determined, so that the resource scheduling and distribution of the power distribution network can be optimized, and the maintenance efficiency of the power distribution network can be improved. The current constant of the target quadrant is determined, in the case that the fault current is greater than the current constant of the target quadrant, overcurrent protection is taken for the target user in the target quadrant, the fault equipment of the target user is isolated in time through the overcurrent protection, the spread of the fault in the power grid can be prevented, the influence of the fault on the overall operation of the power grid is reduced, and the stability of the power system operation is ensured.

[0084] In one of the embodiments of the present embodiment, before acquiring the fault current data and the fault voltage data of the power distribution network, the following steps are included:

[0085] S210, real-time acquisition of current data and voltage data of the power distribution network, and determination of whether the power distribution network has a fault according to the current data and the voltage data;

[0086] S220, in the case that the power distribution network has a fault, the step of acquiring the fault current data and the fault voltage data of the power distribution network is performed.

[0087] The current data and voltage data of the power distribution network are acquired in real time. The current data and voltage data of the power distribution network can be acquired by a data acquisition system. The data acquisition system comprises a measurement unit, an acquisition unit, a synchronization unit and a post-processing unit. The measurement unit mainly comprises a voltage divider, a current sensor and a voltage sensor, and is used to convert the large current signal and high voltage in the circuit into a small analog signal. The acquisition unit is responsible for receiving the small analog signal transmitted by the measurement unit and converting it into a digital signal for storage and transmission. The synchronization unit is used to maintain the synchronization of the post-processing unit and the acquisition unit, and to ensure the accuracy and consistency of the data. The post-processing unit processes and analyzes the collected data to generate a corresponding current and voltage data report. After the current data and voltage data of the power distribution network are acquired by the data acquisition system, it is determined whether the power distribution network has a fault. In this embodiment, the fault of the power distribution network refers to the line fault of the power distribution network. The line fault of the power distribution network is generally caused by line breakage, line short circuit, line grounding, line overload and foreign matter caused phase-to-phase short circuit. The line breakage may be caused by line aging, insulation damage, weather influence and the like. The line short circuit mainly occurs between various phases due to grounding of multiple different phases. The line grounding is usually caused by the user's drop-out fuse, lightning arrester or the breakdown of the insulation of the wall bushing. The line overload refers to the phenomenon that the load is too large or the current is too large, causing the equipment to be burned out or the personal safety to be threatened. The foreign matter caused phase-to-phase short circuit may be caused by foreign matter such as aluminum foil plastic paper, aluminum foil oil felt paper, a scraped television antenna near the line, a scraped tree branch, a discarded recording long tape and the like. These substances may be blown onto the line by strong winds and may cause phase-to-phase short circuit. Whether the power distribution network has a fault is determined according to the current data and voltage data. Whether the power distribution network has a fault is mainly determined by the current spectrum graph and the voltage spectrum graph. Specifically, the similarity of the historical current spectrum graph and the real-time current spectrum graph, and the similarity of the historical voltage spectrum graph and the real-time voltage spectrum graph are compared by constructing the spectrum graph based on the historical current data and the historical voltage data, and constructing the spectrum graph based on the real-time current data and the real-time voltage data, so as to determine whether the power distribution network has a fault.

[0088] When there is a fault in the power distribution network, the fault current data and the fault voltage data are obtained through the smart meter and the sensor. The operation state of the power distribution line can be monitored in real time through the data of the smart meter and the sensor, and the current, voltage, power factor and other parameters, including the monitoring of the fault current and the fault voltage, are monitored in real time. After obtaining the fault current data and the fault voltage data, the fault location is determined based on the fault current data and the fault voltage data, which can be obtained by calculating the complex power of the fault line. In this embodiment, the complex power is the apparent power, which is used to describe the total power in the alternating current circuit, including active power and reactive power. First, the apparent power range of the line is determined, and the fault line is divided based on the preliminary fault type and the preliminary fault severity to obtain a plurality of sub-lines. Second, after determining the plurality of sub-lines, the fault location is determined in the target fault line based on the preset fault positioning technology. In this embodiment, the preset fault positioning technology refers to an automatic and efficient fault point detection and positioning system based on fault indicator technology, GSM communication technology and GIS technology, which is mainly used for detection and positioning of various fault points in the power distribution system. The latitude and longitude coordinates of the fault location in the sub-line are determined through the preset fault positioning technology, so as to obtain the fault location.

[0089] By obtaining the current data and the voltage data of the power distribution network in real time, and determining whether there is a fault in the power distribution network according to the current data and the voltage data, when there is a fault in the power distribution network, the steps of obtaining the fault current data and the fault voltage data of the power distribution network are executed, which can detect the abnormal state of the power distribution network in the first time, and help to reduce the influence of the fault on the power distribution network and the user, and improve the reliability and stability of the system.

[0090] In one of the embodiments of the present embodiment, the phase angle difference of the target line is determined according to the fault current data and the fault voltage data, including:

[0091] S310, obtaining the instantaneous power value of the power distribution network at the fault moment through the fault current data and the fault voltage data, wherein the instantaneous power value includes the reactive power and the active power;

[0092] S320, determining the input value and the output value of the reactive power, and the input value and the output value of the active power based on the reactive power and the active power;

[0093] S330, calculating the power factor of the target line at the fault moment through the input value and the output value of the reactive power, and the input value and the output value of the active power;

[0094] S340, calculating the phase angle difference of the target line according to the power factor by using a preset phase angle formula.

[0095] According to the fault current data and the fault voltage data, the phase angle difference of the target line is determined. Specifically, first, the instantaneous power value of the power distribution network at the fault moment is obtained through the fault current data and the fault voltage data, wherein the instantaneous power value includes the reactive power and the active power. The active power refers to the electrical power required to keep the device running, that is, the electrical power that converts electrical energy into other forms of energy. The reactive power refers to the electrical power required to establish a magnetic field when the inductance, capacitance and other elements in the electrical equipment are working. It is a form of electrical energy, but it cannot do work and cannot be consumed. That is, the instantaneous power value of the power distribution network at the fault moment is determined, which can be obtained by measuring devices such as current transformers and voltage transformers to improve the accuracy of measurement. The instantaneous values of the current and the voltage are obtained, and the instantaneous power calculation formula is used to calculate the instantaneous power. The calculation formula of the instantaneous power is:

[0096] p(t) = v(t) x i(t)

[0097] Wherein, p(t) is the instantaneous power, v(t) is the instantaneous voltage, and i(t) is the instantaneous current.

[0098] The instantaneous power value of the power distribution network at the fault moment is obtained through the instantaneous power calculation formula.

[0099] After obtaining the instantaneous power value, the input value and the output value of the reactive power, and the input value and the output value of the active power are determined based on the reactive power and the active power. That is, the input value and the output value of the reactive power, and the input value and the output value of the active power are calculated respectively by using the instantaneous power calculation formula. In the power system, when the device or the load needs to absorb the reactive power from the power grid, there is an input of the reactive power. For example, inductive load such as motor will absorb reactive power during operation, and these reactive power is used to establish and maintain the magnetic field in the electromagnetic field. On the contrary, when the device or the load sends the reactive power to the power grid, there is an output of the reactive power. For example, capacitive load such as capacitor will send reactive power during charging and discharging. The input value of the active power refers to the actual power absorbed by the device or the load from the power grid, and the power provided by the power grid to the device or the load is used to drive the device to run or meet the energy consumption demand of the load. In the power system, the input value of the active power is usually obtained by measuring the voltage and current flowing through the device or the load, and calculating their product. The output value of the active power refers to the effective power actually output by the device or the load in unit time, which is the part of the power provided by the power grid that is converted into other forms of energy by the device or the load and does work to the outside.

[0100] The phase angle difference at the fault time is calculated by the input and output values of the reactive power and the input and output values of the active power. The phase angle difference refers to the displacement difference between two waves with the same frequency but different phases. In alternating current, it specifically refers to the phase difference between two currents or voltages with the same frequency. Specifically, the phase angle difference can be calculated according to the input and output values of the corresponding power in the four quadrants, for example, the power factor is calculated by the formula of active power, and the formula of active power is as follows:

[0101]

[0102] Where P is the active power, indicating the actual power consumed by the circuit, U is the effective value of the voltage, I is the effective value of the current, and φ is the phase angle difference between the voltage and the current, also known as the power factor angle.

[0103] The power factor is calculated by the formula of reactive power, and the formula of reactive power is as follows:

[0104]

[0105] Where Q is the reactive power, indicating the power exchanged with the power supply due to the energy storage effect of the inductor or capacitor, U is the effective value of the voltage, I is the effective value of the current, and φ is the phase angle difference between the voltage and the current.

[0106] Based on the power input and output modes and the input and output values corresponding to the target quadrant in the target quadrant, the corresponding power factor angle is calculated by the formula of active power and the formula of reactive power.

[0107] The phase angle difference of the target line is calculated according to the power factor angle by using the preset phase angle formula, and the preset phase angle formula is:

[0108]

[0109] Where θ represents the phase angle difference, represents the power factor;

[0110] The phase angle difference of the target line is calculated by using the preset phase angle formula.

[0111] By determining the fault time of the power distribution network through the real-time current spectrum characteristics and the real-time voltage spectrum characteristics, and determining the instantaneous power at the fault time, the power flow at the fault time can be accurately obtained, and the fault location can be quickly located. By the phase angle difference, the target user is determined to be in the target quadrant, and according to the target quadrant of the target user in the four quadrants of the power distribution network, a targeted fault repair strategy can be formulated, which helps to ensure the effectiveness and safety of the measures taken for the fault line.

[0112] In one of the implementations of the embodiment, determining whether the power distribution network has a fault according to the current data and the voltage data comprises:

[0113] S410, obtaining historical sample current data and historical sample voltage data;

[0114] S420, constructing a historical current spectrum and a historical voltage spectrum according to the historical sample current data and the historical sample voltage data;

[0115] S430, constructing a real-time current spectrum and a real-time voltage spectrum according to the real-time obtained current data and voltage data;

[0116] S440, extracting a historical current feature vector of the historical current spectrum and a historical voltage feature vector of the historical voltage spectrum;

[0117] S450, extracting a real-time current feature vector of the real-time current spectrum and a real-time voltage feature vector of the real-time voltage spectrum;

[0118] S460, calculating a first similarity of the historical current feature vector and the real-time current feature vector;

[0119] S470, calculating a second similarity of the historical voltage feature vector and the real-time voltage feature vector;

[0120] S480, if any one of the first similarity and the second similarity is less than a preset similarity threshold, determining that the power distribution network has a fault.

[0121] First, the historical sample current data and the historical sample voltage data are obtained. The data can be collected from the power system in real time by installing data collection software, and the historical data can be recorded automatically. For example, the HiWoo Cloud platform can seamlessly connect various power distribution equipment, including transformers, switch cabinets, circuit breakers, etc., and can collect and store the operating state parameters of the equipment, such as current, voltage, temperature, humidity, etc.

[0122] After obtaining the historical sample current data and the historical sample voltage data, the historical sample current and the historical sample voltage data are constructed into a historical current spectrum graph and a historical voltage spectrum graph. The historical current spectrum graph refers to a graphical representation that records and analyzes the distribution and intensity of the current signal at different frequencies within a certain period of time in the past. It can be obtained by using mathematical methods such as Fourier transform by converting the current signal from time domain to frequency domain. The historical voltage spectrum graph refers to a graphical representation that records and analyzes the distribution and intensity of the voltage signal at different frequencies within a certain period of time in the past. It is usually a visual representation of the voltage signal in the frequency domain, with the horizontal axis representing the frequency and the vertical axis representing the voltage amplitude or power at the corresponding frequency. The spectrum graph can be obtained by Fourier transform, which is a mathematical method mainly used to convert functions from time domain to frequency domain, commonly used in spectral analysis in the field of signal processing. That is, the historical sample current and the historical sample voltage data are converted from time domain to frequency domain by using Fourier transform, and the historical current spectrum graph and the historical voltage spectrum graph are obtained. In this embodiment, the historical current spectrum graph is obtained by the historical sample current, and the historical voltage spectrum graph is obtained by the historical sample voltage.

[0123] Secondly, real-time current spectrum graph and real-time voltage spectrum graph are constructed according to the real-time obtained current data and voltage data. The real-time current spectrum graph shows the real-time distribution and intensity of the current signal at different frequencies, which is usually represented by converting the current signal from time domain to frequency domain in real time, and is realized by relying on efficient algorithms such as fast Fourier transform. The real-time voltage spectrum graph is used to show the real-time distribution and intensity of the voltage signal at different frequencies, which is usually represented by converting the voltage signal from time domain to frequency domain in real time, and is realized by relying on efficient algorithms such as fast Fourier transform. The spectrum graph can be obtained by Fourier transform, which is a mathematical method mainly used to convert functions from time domain to frequency domain, commonly used in spectral analysis in the field of signal processing. That is, the real-time obtained current data and voltage data are converted from time domain to frequency domain by using Fourier transform, and the real-time current spectrum graph and the real-time voltage spectrum graph are obtained. In this embodiment, the real-time current spectrum graph is obtained by the real-time obtained current data, and the real-time voltage spectrum graph is obtained by the real-time obtained voltage data.

[0124] After constructing the historical current frequency spectrum and the historical voltage frequency spectrum, the historical current feature vector of the historical current frequency spectrum and the historical voltage feature vector of the historical voltage frequency spectrum are extracted, and a neural network model can be used for feature extraction. The convolutional layer of the neural network model can perform convolution operation on the input data through a series of learnable convolution kernels, thereby extracting local features in the image, such as edges, textures, shapes, etc. The convolutional layer of the convolutional neural network is used to extract the features of the historical current frequency spectrum and the historical voltage frequency spectrum, and the amplitude, frequency distribution and amplitude feature vector of the historical current frequency spectrum and the historical voltage frequency spectrum are determined.

[0125] Subsequently, the real-time current feature vector and the real-time voltage feature vector are extracted from the real-time current frequency spectrum and the real-time voltage frequency spectrum. A convolutional neural network can also be used for feature extraction. Similarly, the convolutional layer of the convolutional neural network is used to extract the features of the real-time current frequency spectrum and the real-time voltage frequency spectrum, and the intensity, frequency distribution and amplitude feature vector of the real-time current frequency spectrum and the real-time voltage frequency spectrum are determined.

[0126] After determining the historical voltage feature vector, the historical current feature vector, the real-time voltage feature vector and the real-time current feature vector, the first similarity between the historical current feature vector and the real-time current feature vector is calculated. In this embodiment, the first similarity refers to the similarity between the historical current feature vector and the real-time current feature vector. The first similarity can be calculated by cosine similarity, which is an index for measuring the similarity of the direction of two vectors. The principle is based on the vector space model, which represents documents or data items as vectors and calculates the cosine value between these vectors. The similarity is obtained by calculating the cosine value of the angle between the historical current feature vector and the real-time current feature vector. When the cosine value is closer to 1, it means that the two feature vectors are more similar, and when the cosine value is closer to 0, it means that the two feature vectors are less similar.

[0127] The second similarity between the historical voltage feature vector and the real-time voltage feature vector is calculated. In this embodiment, the second similarity refers to the similarity between the historical voltage feature vector and the real-time voltage feature vector. The second similarity can be calculated by cosine similarity, which is an index for measuring the similarity of the direction of two vectors. The principle is based on the vector space model, which represents documents or data items as vectors and calculates the cosine value between these vectors. The similarity is obtained by calculating the cosine value of the angle between the historical voltage feature vector and the real-time voltage feature vector. When the cosine value is closer to 1, it means that the two feature vectors are more similar, and when the cosine value is closer to 0, it means that the two feature vectors are less similar.

[0128] After determining the first similarity and the second similarity, the first similarity and the second similarity are compared with a preset similarity threshold, which can be determined according to actual conditions. When one of the first similarity and the second similarity is less than the preset similarity threshold, for example, when the preset current similarity threshold is 80% and the preset voltage similarity threshold is 80%, any one of the first similarity and the second similarity calculated is less than 80%, it is determined that the power distribution network has a fault.

[0129] By converting the current and voltage data into frequency spectrum diagrams, the frequency distribution and change trend of the data can be clearly seen, and the slight changes and abnormalities in the current and voltage data can be captured, thereby improving the accuracy of fault detection. By calculating the similarity between the historical feature vector and the real-time feature vector, it can be determined that the power distribution network has a fault and effective measures can be taken in time, thereby improving the accuracy of fault detection and ensuring the stable operation of the power system.

[0130] In one of the embodiments of the present embodiment, the real-time current feature vector includes a current amplitude and a current phase, and the real-time voltage feature vector includes a voltage amplitude and a voltage phase. After constructing the real-time current frequency spectrum diagram and the real-time voltage frequency spectrum diagram from the real-time current data and the real-time voltage data, the method includes:

[0131] S510, determining whether the real-time current frequency spectrum diagram has signal interference by the current amplitude and the current phase of the real-time current frequency spectrum diagram;

[0132] S520, if the current amplitude in the real-time current frequency spectrum diagram is greater than a preset reference amplitude and the offset value of the current phase is greater than a preset phase threshold, it is determined that the real-time current frequency spectrum diagram has signal interference;

[0133] S530, correcting the real-time current frequency spectrum diagram by using a preset frequency spectrum correction method;

[0134] S540, determining whether the real-time voltage frequency spectrum diagram has signal interference by the voltage amplitude and the voltage phase of the real-time voltage frequency spectrum diagram;

[0135] S550, if the voltage amplitude in the real-time voltage frequency spectrum diagram is greater than a preset reference amplitude and the offset value of the voltage phase is greater than a preset phase threshold, it is determined that the real-time voltage frequency spectrum diagram has signal interference;

[0136] S560, correcting the real-time voltage frequency spectrum diagram by using a preset frequency spectrum correction method.

[0137] After constructing the real-time current spectrum and the real-time voltage spectrum from the real-time current data and the real-time voltage data, first, whether the real-time current spectrum has signal interference is determined by the current amplitude and the current phase of the real-time current spectrum. The signal interference may generally be electromagnetic radiation interference. An external electromagnetic field may radiate interference to a current spectrum measurement device, such as radio waves, lightning, etc. which may have some impact on the current spectrum. In addition, when multiple signals are transmitted at the same time, they may generate mutual effects between them to generate new interference signals. Such interference is particularly common in communication systems and may also have an impact on current spectrum measurement. In this embodiment, electromagnetic radiation interference in the real-time current spectrum is mainly analyzed. When electromagnetic radiation interference occurs in the current spectrum, the current spectrum may have phase deviation, such as phase delay or advance. The phase deviation may be manifested as a shift in the phase angle of each frequency component in the spectrum, which no longer maintains the phase relationship of the original signal. The amplitude of the current spectrum may also have amplitude deviation, such as electromagnetic radiation interference which may be manifested as high-frequency noise or random noise. These noises may be superimposed on the original current signal, causing fluctuations or increases in the amplitude of the spectrum, resulting in an increase in the amplitude of some frequency components in the spectrum and a shift phenomenon, while the amplitude of other frequency components may be underestimated. Therefore, when the current amplitude and the current phase of the real-time current spectrum deviate, it is determined that the real-time current spectrum has signal interference. Specifically, if the current amplitude in the real-time current spectrum is greater than a preset reference amplitude and the phase deviation value of the current phase is greater than a preset phase threshold, it is determined that the real-time current spectrum has signal interference. The preset threshold may be determined according to the actual situation. When there is electromagnetic radiation interference, the current amplitude may be greater than the preset reference amplitude. Since the interference signal is usually superimposed on the original signal, the amplitude increases. When the current amplitude deviation value is greater than the preset reference amplitude, it is determined that the real-time current spectrum has signal interference.

[0138] When the real-time current spectrum has signal interference, a preset spectrum correction method is used to correct the real-time current spectrum. In this embodiment, the preset spectrum correction method may be a smoothing method. The real-time current spectrum can be corrected by the smoothing method. By smoothing the spectrum signal, the influence of noise on the spectrum signal can be reduced. The smoothing method is to give a weighted average to the continuously obtained actual data and the original prediction data, so that the prediction result is closer to the actual situation. By using the smoothing method to perform weighted average processing on the current signal data, the accuracy of the obtained actual data is improved, the interference of the electromagnetic radiation signal on the current signal is reduced, and the real-time current spectrum is more accurate, so as to correct the real-time current spectrum with interference.

[0139] After the real-time current spectrogram is corrected, whether the real-time voltage spectrogram has signal interference is determined through the voltage amplitude and the voltage phase of the real-time voltage spectrogram. The signal interference of the real-time voltage spectrogram generally has electromagnetic interference, such as power frequency interference and radio frequency interference, mutual interference between devices, such as the electromagnetic field between multiple electronic devices when they work at the same time, which may interfere with each other. In the present embodiment, the signal interference of the real-time voltage spectrogram mainly analyzes the power frequency interference in the electromagnetic interference. The power frequency interference is generally electromagnetic field radiation interference generated by the power transmission and distribution system and the electric traction system. When electromagnetic field radiation interference occurs, the voltage amplitude in the real-time voltage spectrogram will increase. Electromagnetic field radiation interference is usually manifested as broadband noise or a peak value at a specific frequency in the spectrogram. These interference signals will be superimposed on the original signal, resulting in an increase in the noise floor of the voltage spectrogram. Therefore, after electromagnetic field radiation interference occurs, the voltage amplitude in the real-time voltage spectrogram will increase. At the same time, when electromagnetic field radiation interference occurs, the voltage phase in the real-time voltage spectrogram will have a phase shift. Therefore, when the voltage amplitude and the voltage phase of the real-time voltage spectrogram deviate, it is determined that the real-time voltage spectrogram has signal interference. Specifically, if the voltage amplitude in the real-time voltage spectrogram is greater than a preset reference amplitude and the phase shift value of the voltage phase is greater than a preset phase threshold, it is determined that the real-time voltage spectrogram has signal interference. The preset threshold can be determined according to the actual situation. When electromagnetic radiation interference exists, the voltage amplitude will be greater than the preset reference amplitude. Since the interference signal is usually superimposed on the original signal, resulting in an increase in the amplitude, when the voltage amplitude deviates by a value greater than the preset reference amplitude, it is determined that the real-time voltage spectrogram has signal interference.

[0140] When the real-time voltage spectrogram has signal interference, a preset spectrum correction method is used to correct the real-time voltage spectrogram. In the present embodiment, the preset spectrum correction method can be a smoothing method. The real-time voltage spectrogram can be corrected by the smoothing method. By smoothing the spectrum signal, the influence of noise on the spectrum signal can be reduced. The smoothing method is to give a weighted average to the continuously obtained actual data and the original prediction data, so that the prediction result is closer to the actual situation. By using the smoothing method to perform weighted average processing on the voltage signal data, the accuracy of the obtained actual data is improved, the interference of electromagnetic radiation signals on the voltage signal is reduced, and the real-time voltage spectrogram is more accurate, so as to correct the real-time voltage spectrogram with interference.

[0141] By determining whether the real-time current spectrogram and the real-time voltage spectrogram have signal interference and correcting the real-time current spectrogram and the real-time voltage spectrogram, the interference signals can be effectively reduced or eliminated, thereby improving the quality of the voltage signal and the current signal, enhancing the system stability, optimizing data analysis and reducing maintenance cost, and ensuring the stable operation of the power system and the accuracy of data processing.

[0142] In one of the implementations of the present embodiment, the method further comprises:

[0143] S610, calculating the complex power of the fault line through the fault current data and the fault voltage data;

[0144] S612, determining the power range where the complex power is located;

[0145] S613, determining the preliminary fault type and the preliminary fault severity through the power range;

[0146] S614, dividing the target line based on the preliminary fault type and the preliminary fault severity to obtain a plurality of sub-lines;

[0147] S615, determining the fault sub-line and the fault position in the fault sub-line through a preset fault locating technology for each sub-line.

[0148] Based on the fault current data and the fault voltage data, the fault position is determined. Specifically, the complex power of the fault line is calculated through the fault current data and the fault voltage data. In the present embodiment, the complex power is the apparent power. The apparent power is used to describe the total power in an alternating current circuit, including active power and reactive power. The calculation formula of the apparent power is as follows:

[0149] S=P+jQ

[0150] Wherein, S represents the apparent power, P represents the active power, Q represents the reactive power, and j represents the imaginary unit;

[0151] The real part of the complex power is the active power, and the imaginary part is the reactive power. By calculating the complex power of the fault line and analyzing the real part and the imaginary part of the complex power, the preliminary fault type can be determined. The preliminary fault type can be a short-circuit fault, a broken line fault, and a ground fault. For example, if the reactive power is large, it may indicate the existence of a fault with capacitive or inductive properties, such as arc discharge in a ground fault. The power range where the complex power is located is determined, and the preliminary fault severity is determined. The size of the complex power can reflect the severity of the fault. When there is a large complex power, it may mean that the fault point releases or loses a large amount of energy, which needs to be handled more urgently. That is, the complex power is compared with the preset power range. Different power ranges correspond to different severities. For example, the preset power range can be set as a slight fault, a general fault, and a serious fault according to actual conditions. The corresponding severity is determined by determining which power range the complex power is in.

[0152] When the fault type and the fault severity are preliminarily determined, the fault line is divided according to the preliminarily determined fault type and the preliminarily determined fault severity, that is, the fault line is divided based on the power range, which is the power range in which the composite power is located in the embodiment, when there are multiple fault types, the fault line is divided according to the fault type, such as short-circuit fault, broken line fault and ground fault, and when the fault type is one, the fault line is divided according to the fault severity, such as slight fault, general fault and serious fault, so as to determine multiple sub-lines.

[0153] After the multiple sub-lines are determined, the fault position in the sub-line is determined based on the preset fault positioning technology, which is a set of automatic and efficient fault point detection and positioning system based on fault indicator technology, GSM communication technology and GIS technology, and is mainly used for detection and positioning of various fault points in the power distribution system. The fault indicator technology refers to a device installed on the power line for indicating the fault current, which can determine the circuit fault by detecting the characteristics of the fault current. The GSM communication technology is a widely used second-generation digital cellular mobile communication standard. The GIS technology is a computer-based tool for analyzing and processing spatial information. The latitude and longitude coordinates of the fault position in the sub-line can be accurately determined by the preset fault positioning technology, so as to determine the fault position in the sub-line.

[0154] The composite power of the fault line is calculated by the fault current data and the fault voltage data, which can determine the preliminary fault type and the preliminary fault severity, and help to accurately determine the fault type and the severity and take corresponding processing measures. Based on the preliminary fault type and the preliminary fault severity, the fault line is divided to obtain multiple sub-lines, and based on the preset fault positioning technology, the fault position in the sub-line is determined. According to the fault type and the severity, a targeted fault processing scheme can be developed, which can help to improve the efficiency and quality of fault processing, timely discover and handle faults, prevent the expansion of faults and avoid greater damage to the power system.

[0155] In one of the embodiments of the embodiment, before obtaining the fault current data of the target line in the power distribution network at the fault moment, the method further comprises:

[0156] S710, obtaining the terminal node and the branch node in the power distribution line of the target phase, wherein the branch node is located at the connection between the branch line of the power distribution line and the main line of the power distribution line, and the terminal node is located at the connection between the branch line of the power distribution line and the load device;

[0157] S720, the terminal node and the branch node constitute a section of the power distribution line, the section of the power distribution line includes a main line section and a branch line section, the line between the terminal node and the branch node is the branch line section, and the line between the branch node and the adjacent branch node is the main line section;

[0158] S730, determine the influence degree of each section, and determine at least one target line according to the influence degree.

[0159] According to the fault current phase angle difference, the fault type is determined, and the target quadrant of the fault type in the four-quadrant power distribution network is determined, including:

[0160] S740, determine the preset angle range in which the phase angle difference is located, and determine the user fault type corresponding to the target line through the preset angle range;

[0161] S750, according to the user fault type, determine the target quadrant corresponding to the user type in the four-quadrant power distribution network.

[0162] Based on the phase angle difference at the fault moment, the target user is determined to be in the target quadrant in the four-quadrant power distribution network. Specifically, first, the power distribution line in the fault quadrant is phase-converted to obtain the power distribution line in the target phase, and the target phase includes the first modal phase and the second modal phase. In this embodiment, the power distribution line in the fault quadrant is phase-converted by Clarke transformation to convert the power distribution line in the fault quadrant from the three-phase stationary coordinate system to the two-phase stationary coordinate system. Clarke transformation is a commonly used coordinate transformation method in motor control and power systems. The core idea is to convert the current or voltage in the three-phase stationary coordinate system into the current or voltage in the two-phase stationary coordinate system for analysis and control, that is, the power distribution line in the fault quadrant is converted from the three-phase stationary coordinate system to the two-phase stationary coordinate system by Clarke transformation, and in this embodiment, the three-phase stationary coordinate system is the abc coordinate system, and the two-phase stationary coordinate system is the coordinate system in the first modal phase and the coordinate system in the second modal phase, so as to obtain the target phase, and in this embodiment, the target phase includes the first modal phase and the second modal phase, which is obtained by Clarke transformation.

[0163] Figure 3 An illustrative structure diagram of a main line section and a branch line section of a power distribution network according to an embodiment of the application is shown, as shown in the figure, the main line of the power distribution line includes a terminal node and a branch node, the line between the terminal node and the branch node is the branch line section, and the line between the branch node and the adjacent branch node is the main line section;

[0164] After obtaining the target phase of the power distribution line, the terminal nodes and branch nodes in the target phase of the power distribution line are obtained. In this embodiment, the branch nodes are located at the connection between the branch line of the power distribution line and the main line of the power distribution line, and the terminal nodes are located at the connection between the branch line of the power distribution line and the load device. The branch node refers to the position where the current or signal is branched or merged in the power distribution line. In the power distribution network, the branch node is usually located at the connection between the main line and the branch line, and plays the role of distributing or collecting current. The terminal node refers to the final receiving point or sending point of the current or signal in the power distribution line. In the power distribution system, the terminal node usually refers to the node directly connected to the power supply or load. As the end of the power distribution line, the terminal node is directly connected to the load or user device, which is the starting point of the use of electric energy and is also a key node in the power distribution line.

[0165] After obtaining the terminal nodes and branch nodes in the target phase of the power distribution line, the terminal nodes and branch nodes form a section of the power distribution line. In this embodiment, the section of the power distribution line includes a main line section and a branch line section, wherein the line between the terminal node and the branch node is the branch line section, and the line between the branch node and the adjacent branch node is the main line section. The main line section refers to the line part connecting adjacent branch nodes, which is usually the backbone part in the power distribution network and is responsible for transmitting electric energy from the power supply end to each branch node. The branch line section refers to the line part from the branch node to the terminal node, which is responsible for distributing electric energy from the main line section to specific load points.

[0166] After determining the main line section and the branch line section in the power distribution line, the influence degree of each section is determined. In this embodiment, the influence degree of each section refers to the influence of the fault line on the fluctuation of the electrical parameter of other lines, and the target line is determined according to the influence degree. That is, by judging the change of the electrical parameter in the power distribution line, the influence degree of each section is determined, and the target line is determined according to the influence degree of each section. In this embodiment, the target line is the section with an influence degree greater than a preset threshold value, and the section with an influence degree greater than the preset threshold value is taken as the target section.

[0167] According to the fault current phase angle difference, the fault type is determined, and the target quadrant of the fault type in the four-quadrant of the power distribution network is determined, that is, by comparing the fault current phase angle difference with the known fault type characteristics, the fault type is obtained, for example, in the case of symmetric fault, the phase angle difference of three-phase voltage and current is 120°, and the phase angles of positive sequence components are consistent, and the phase angle of negative sequence component is 0°. In the case of asymmetric fault, the phase angle difference of three-phase voltage and current is not 120°, and the phase angles of positive sequence components and negative sequence components are different. Common asymmetric fault types include single-phase ground fault, two-phase short circuit fault, etc. Asymmetric fault refers to the fault that the three-phase voltage and current are asymmetric in amplitude or phase. This is because asymmetric fault will cause the size and phase of three-phase current to be no longer equal or differ by a fixed angle, so the phase angle difference also presents the characteristics of asymmetric distribution. If the phase angle difference meets the characteristics of symmetric fault, such as the phase angle difference of three-phase is 120°, and the phase angles of positive sequence components are consistent, and the phase angle of negative sequence component is 0°, it is judged as symmetric fault, if the phase angle difference does not meet the characteristics of symmetric fault, it is further analyzed whether it meets the characteristics of asymmetric fault. After determining the fault type, the fault type is determined, and the target quadrant of the fault type in the four-quadrant of the power distribution network is determined, specifically, the preset angle range of the phase angle difference is determined, and the user type corresponding to the target line is determined through the preset angle range, after obtaining the user type, the target quadrant corresponding to the user type in the four-quadrant of the power distribution network is determined, for example, the phase difference is between 0° and 90°, and the power factor is greater than 0, the target user is in the first quadrant; the phase difference is between -90° and 0°, and the power factor is less than 0, indicating that active power is sent and reactive power is absorbed, the target user is in the second quadrant; the phase difference is between -90° and -180°, and the power factor is less than 0, indicating that active power and reactive power are sent, the target user is in the third quadrant; the phase difference is between 0° and 90°, and the power factor is greater than 0, but the current direction is opposite to the voltage direction, the target user is in the fourth quadrant.

[0168] In another embodiment of the present embodiment, after determining the target line, the determination of the fault type is realized by the following steps, specifically, this step simplifies the analysis of complex three-phase asymmetric circuit by decomposing asymmetric components such as current or voltage in three-phase circuit into three groups of symmetric components, namely positive sequence, negative sequence and zero sequence components. In the first modal phase, the first phase angle difference value of each target line is determined, and according to the first phase angle difference value, whether it is a preset first fault type is determined, if it is the first fault type, the target fault type is determined, specifically, in the present embodiment, the first phase angle difference value refers to the phase angle difference value of the target line in the first modal phase, first, the current value of the target line in the first modal phase is obtained, and the first phase angle difference value is derived by using the Clarke transformation formula and the current value in the first modal phase, the Clarke transformation formula is as follows:

[0169]

[0170] wherein, represents the current value in the first modal phase, I a , I b and I c represents the three-phase current phasor value, represents the first phase angle difference value in the first modal phase;

[0171] Therefore, the formula of the phase angle difference in the first modal phase can be calculated by using the following transformation formula, as shown below:

[0172]

[0173] represents the first phase angle difference value in the first modal phase, θ a , θ b and θ c represents the three-phase corresponding phasor angle;

[0174] When the a-phase fault occurs in the three-phase circuit, the first phase angle difference value in the first modal phase is not 0. When the b-phase and c-phase faults occur, the first phase angle difference value in the first modal phase is also not 0. When the fault type is bc-phase short circuit, the first phase angle difference value in the first modal phase is 0.

[0175] Therefore, by analyzing the first phase angle difference value to determine whether the first phase angle difference value is 0, and further determining whether the first fault type is bc-phase short circuit or a-phase fault, b-phase and c-phase fault. For example, when the first phase angle difference value is 0, it can be determined that the first fault type is bc-phase short circuit; when the first phase angle difference value is not 0, it is determined that the first fault type is a-phase fault or b-phase and c-phase fault, when the first phase angle difference value is not 0, the phase angle difference needs to be analyzed in the second modal phase to further determine the fault type.

[0176] Subsequently, in the second modal phase, the second phase angle difference value of each target line is determined, and the second target fault line is obtained, wherein the second phase angle difference value in the second modal phase refers to the phase angle difference value of the target line at both ends in the second modal phase. First, the current value in the second modal phase at both ends of the target line is obtained, and the second phase angle difference value is derived by using the transformation formula and the current value in the second modal phase, and the transformation formula is shown as follows:

[0177]

[0178] wherein, I β represents the current value in the first modal phase, I b and Ic θ represents the b-phase current and c-phase current in a three-phase system. β This represents the numerical value of the second phase angle difference within the second mode phase;

[0179] Therefore, the formula for the phase angle difference within the second mode phase can be derived using the transformation formula, as shown below:

[0180]

[0181] θ β θ represents the numerical value of the second phase angle difference within the second mode phase. b and θ c I represents the phasor angles corresponding to phases b and c in the three-phase system. b and I c This represents the b-phase current and c-phase current in a three-phase system.

[0182] The second target faulty line is determined by the second phase angle difference value. Specifically, when a fault occurs in phase b or phase c, the second phase angle difference value within the second mode phase is not 0. When a fault occurs in phase a, the second phase angle difference value is 0.

[0183] Therefore, by analyzing the value of the second phase angle difference, it can be determined whether the second fault type is a short circuit between phases b and c, a fault in phase a, or a fault in both phases b and c. For example, when the value of the second phase angle difference is not 0, it can be determined that the fault type is a fault in phase b or phase c; when the value of the second phase angle difference is 0, it can be determined that the fault type is a fault in phase a.

[0184] Determining the target quadrant of the distribution network by measuring the phase angle difference at the moment of a fault allows for faster fault location, shortens fault investigation time, helps to promptly identify and address potential power system instability factors, and improves power system stability.

[0185] In one embodiment of this example, determining the degree of impact for each segment and, based on the degree of impact, determining at least one target line includes:

[0186] S801, Obtain the transmission power of each segment at the time of the fault;

[0187] S802. Compare each transmission power with a preset reference power, mark the segments that exceed the preset reference power, and obtain the super-reference power segments.

[0188] S803. Compare the transmission power of each segment at the time of the fault with the preset reference power, and mark the segments that do not exceed the preset reference power to obtain the segments that do not exceed the reference power.

[0189] S804, determine the difference between each super-reference power section and the preset reference power, and obtain a first power number set;

[0190] S805, determine the difference between each non-super-reference power section and the preset reference power, and obtain a second power number set;

[0191] S806, construct a matrix with the first power number set and the second power number set, wherein the row vectors in the matrix represent each section, and the column vectors in the matrix are composed of the first power number set and the second power number set;

[0192] S807, determine the influence degree of each section based on the preset risk assessment matrix;

[0193] S808, multiply the influence degree of each section with the power value of each corresponding section in the matrix to obtain an influence degree matrix;

[0194] S809, mark the sections in the influence degree matrix that exceed the preset threshold value as target lines.

[0195] Determine the influence degree of each section, and determine the target line according to the influence degree. Specifically, first, obtain the transmission power of each section at the fault time, which can be directly measured by a power measuring device such as a power meter. Transmission power represents the electrical energy transmitted by a certain circuit or device in a unit of time. In a power system, the size of transmission power is directly related to the distribution, utilization and efficiency of electrical energy.

[0196] After determining the transmission power, compare each transmission power with the preset reference power, mark the sections that exceed the preset reference power, and obtain the super-reference power section. The preset reference power can be determined according to the capacity, load demand and safety of the actual power system. That is, compare the transmission power data of each section with the preset reference power, and identify the sections that exceed the reference power. The sections that exceed the reference power may have problems such as overload, voltage fluctuation or power oscillation, and are marked for subsequent analysis and processing, so as to determine the super-reference power section. In this embodiment, the super-reference power section is the section that exceeds the preset reference power.

[0197] Similarly, the transmission power of each section at the fault moment is compared with the preset reference power, and the section that does not exceed the preset reference power is marked to obtain a section that does not exceed the reference power. The preset reference power can be determined according to the capacity, load demand and safety of the actual power system. In this embodiment, the section that does not exceed the reference power is the section that does not exceed the preset reference power. That is, the transmission power data of each section is compared with the preset reference power, and the section that does not exceed the reference power is identified and marked for subsequent analysis and processing, so as to determine the section that does not exceed the reference power.

[0198] After determining the section that does not exceed the reference power and the section that exceeds the reference power, the difference between the section that exceeds the reference power and the preset reference power is determined to obtain a first power number set. In this embodiment, the first power number set is a set of power difference values obtained by subtracting the reference power from the transmission power. That is, the power difference values are obtained by subtracting the reference power from the transmission power. Since the power value of the section that does not exceed the reference power is less than the preset reference power, the power value in the first power number set is 0 or negative.

[0199] After obtaining the first power number set, the difference between the section that exceeds the reference power and the preset reference power is determined to obtain a second power number set. In this embodiment, the second power number set is a set of power difference values obtained by subtracting the reference power from the transmission power. That is, the power difference values are obtained by subtracting the reference power from the transmission power. Since the power value of the section that exceeds the reference power is greater than the preset reference power, the power value in the first power number set is positive.

[0200] After obtaining the first power number set and the second power number set, the first power number set and the second power number set form a matrix, wherein the row vectors in the matrix represent each section, and the column vectors in the matrix are composed of the first power number set and the second power number set. That is, each section is taken as a row vector of the matrix, and the difference between the section that exceeds the reference power and the preset reference power and the difference between the section that exceeds the reference power and the preset reference power are taken as column vectors of the matrix, so as to obtain the matrix.

[0201] Based on the preset risk assessment matrix, the influence degree of each section is determined. The preset risk assessment matrix is usually composed of a two-dimensional table. The horizontal axis represents the possibility of risk occurrence, and the vertical axis represents the influence degree of risk. The cells in the matrix can be classified and color-coded according to the possibility and influence degree of risk to reflect the level of risk. Common color coding includes red high risk, yellow medium risk and green low risk. That is, the influence degree value of each section due to the failure of the power distribution network is determined through the preset risk assessment matrix, and the target line is determined through the influence degree of each section.

[0202] After the influence degree of each section is obtained, the influence degree of each section is multiplied by the power value of each corresponding section in the matrix to obtain an influence degree matrix, which in this embodiment refers to a matrix of the influence degree of the power distribution line fault on other middle section lines. Each row of the matrix represents a line section, and the value in the matrix represents the influence degree product of the section.

[0203] Sections in the influence degree matrix that exceed a preset threshold value are marked as target lines. The preset threshold value can be determined according to actual conditions, that is, sections exceeding the threshold value are marked to obtain target lines.

[0204] By determining the influence degree of each section and finally determining the target lines, the risk sections can be accurately identified, the risk influence can be quantified, the operation efficiency of the power system can be improved, and the safe, stable and efficient operation of the power system can be ensured.

[0205] The embodiment of the application further provides a machine readable storage medium, which stores instructions for causing a machine to execute the power distribution network four-quadrant adaptive intelligent current protection method.

[0206] The embodiment of the application further provides a power distribution network four-quadrant adaptive intelligent current protection system, which comprises:

[0207] a memory configured to store instructions; and

[0208] a processor configured to call the instructions from the memory and capable of implementing the power distribution network four-quadrant adaptive intelligent current protection method when the instructions are executed.

[0209] Those skilled in the art should understand that the embodiments of the application can be provided as a method, a system or a computer program product. Therefore, the application can be in the form of a complete hardware embodiment, a complete software embodiment or an embodiment combining software and hardware aspects. Moreover, the application can be in the form of a computer program product implemented on one or more computer usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer usable program code.

[0210] The computer program instructions can also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer-implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart block or blocks. Figure 1 one or more flowcharts and / or blocks in the flowcharts and / or combination thereof. Figure 1 one or more flowcharts and / or blocks in the flowcharts and / or combination thereof.

[0211] The computer program instructions can also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer-implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart block or blocks. Figure 1 one or more flowcharts and / or blocks in the flowcharts and / or combination thereof. Figure 1 one or more flowcharts and / or blocks in the flowcharts and / or combination thereof.

[0212] The computer program instructions can also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer-implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart block or blocks. Figure 1 one or more flowcharts and / or blocks in the flowcharts and / or combination thereof. Figure 1 one or more flowcharts and / or blocks in the flowcharts and / or combination thereof.

[0213] In one typical configuration, the computing device includes one or more processors (CPUs), input / output interfaces, network interfaces, and memory.

[0214] The memory can include non-persistent memory and / or volatile memory, such as a random access memory (RAM) including a cache area for the temporary storage of data. The memory can also include non-volatile memory, such as read only memory (ROM) for storing structural information and / or instruction code to implement the functions of the computing device. The memory can additionally or alternatively include mass storage for persistent storage of information and instructions.

[0215] Computer-readable media includes permanent and non-permanent, movable and non-movable media that can implement information storage by any method or technology. The information can be computer-readable instructions, data structures, program modules or other data. Examples of computer storage media include, but are not limited to, phase-change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technologies, compact disc read-only memory (CD-ROM), digital versatile disc (DVD) or other optical storage, magnetic cassette, magnetic tape disk storage or other magnetic storage devices, or any other non-transmission medium that can be used to store information accessible to a computing device. According to the definition herein, computer-readable media does not include transitory media such as modulated data signals and carriers.

[0216] It should also be noted that the terms "comprising", "containing", or any other variant thereof are intended to cover a non-exclusive inclusion, such that a process, method, article or apparatus that comprises a list of elements does not only include those elements, but can also include other elements not expressly listed or inherent to such process, method, article or apparatus. Without more limitations, the element defined by the statement "comprising a" does not exclude the presence of additional identical elements in the process, method, article or apparatus that includes the element.

[0217] The above is only an embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the scope of claims of the present application.

Claims

1. A four-quadrant adaptive intelligent current protection method for power distribution network, characterized in that, The method comprises the following steps: obtaining fault current data and fault voltage data of a target line in a power distribution network at a fault moment; determining the phase angle difference of the target line according to the fault current data and the fault voltage data; determining the fault type and the target quadrant of the fault type in the four-quadrant of the power distribution network according to the phase angle difference of the target line, wherein the fault type includes a resistive and inductive load user fault, a non-clean energy power generation user fault, a clean energy power generation user, a resistive and capacitive load user fault, and a line fault after the power flow direction changes after the operation mode changes; determining whether the fault current data is greater than the current setting value corresponding to the target quadrant, and performing overcurrent protection on the target user fault and the line fault after the power flow direction changes after the operation mode changes due to the different fault currents under different operation modes when the fault current data is greater than the current setting value.

2. The method of claim 1, wherein, In the four-quadrant of the power distribution network, the resistive and inductive load user is located in the first quadrant of the four-quadrant, the non-clean energy power generation user is located in the second quadrant of the four-quadrant, the clean energy power generation user is located in the third quadrant of the four-quadrant, and the resistive and capacitive load user is located in the fourth quadrant of the four-quadrant, wherein the resistive and inductive load user is used to input active power and input reactive power to the power distribution network, the non-clean energy power generation user is used to output active power and input reactive power to the power distribution network, the clean energy power generation user is used to output active power and output reactive power to the power distribution network, and the resistive and capacitive load user is used to input active power and output reactive power to the power distribution network. Before the step of obtaining the fault current data and the fault voltage data of the target line in the power distribution network at the fault moment, the method comprises the following steps: obtaining current data and voltage data of the power distribution network in real time, and determining whether there is a fault in the power distribution network according to the current data and the voltage data; if there is a fault in the power distribution network, performing the step of obtaining the fault current data and the fault voltage data of the target line in the power distribution network at the fault moment.

3. The method of claim 2, wherein, The step of determining the phase angle difference of the target line according to the fault current data and the fault voltage data comprises the following steps: obtaining the instantaneous power value of the power distribution network at the fault moment through the fault current data and the fault voltage data, wherein the instantaneous power value includes the reactive power and the active power; determining the input value and the output value of the reactive power and the input value and the output value of the active power based on the reactive power and the active power; calculating the power factor of the target line at the fault moment through the input value and the output value of the reactive power and the input value and the output value of the active power; calculating the phase angle difference of the target line according to the power factor by using a preset phase angle formula.

4. The method of claim 3, wherein, The step of determining whether there is a fault in the power distribution network according to the current data and the voltage data comprises the following steps: obtaining historical sample current data and historical sample voltage data; constructing a historical current spectrum diagram and a historical voltage spectrum diagram according to the historical sample current data and the historical sample voltage data; constructing a real-time current spectrum and a real-time voltage spectrum according to the real-time current data and the real-time voltage data; extracting a historical current feature vector of the historical current spectrum and a historical voltage feature vector of the historical voltage spectrum; extracting a real-time current feature vector of the real-time current spectrum and a real-time voltage feature vector of the real-time voltage spectrum; calculating a first similarity between the historical current feature vector and the real-time current feature vector; calculating a second similarity between the historical voltage feature vector and the real-time voltage feature vector; determining that the power distribution network has a fault if any one of the first similarity and the second similarity is less than a preset similarity threshold.

5. The method of claim 4, wherein, The real-time current feature vector includes a current amplitude and a current phase, and the real-time voltage feature vector includes a voltage amplitude and a voltage phase. After the real-time current data and the real-time voltage data are constructed into the real-time current spectrum and the real-time voltage spectrum, the method further includes: determining whether the real-time current spectrum has signal interference through the current amplitude and the current phase of the real-time current spectrum; determining that the real-time current spectrum has signal interference if the current amplitude in the real-time current spectrum is greater than a preset reference amplitude and an offset value of the current phase is greater than a preset phase threshold; correcting the real-time current spectrum by using a preset spectrum correction method; determining whether the real-time voltage spectrum has signal interference through the voltage amplitude and the voltage phase of the real-time voltage spectrum; determining that the real-time voltage spectrum has signal interference if the voltage amplitude in the real-time voltage spectrum is greater than a preset reference amplitude and an offset value of the voltage phase is greater than a preset phase threshold; correcting the real-time voltage spectrum by using a preset spectrum correction method.

6. The method of claim 1, wherein, The method further includes: calculating a complex power of a fault line through the fault current data and the fault voltage data; determining a power range in which the complex power is located; determining a preliminary fault type and a preliminary fault severity through the power range; dividing the target line to obtain a plurality of sub-lines based on the preliminary fault type and the preliminary fault severity; determining a fault sub-line and a fault position in the fault sub-line by using a preset fault locating technology for each of the sub-lines.

7. The method of claim 6, wherein, Before the method of acquiring the fault current data of the target line of the power distribution network at the fault moment, the method further includes: acquiring a terminal node and a branch node in the power distribution line of the target phase, wherein the branch node is located at a connection between a branch line of the power distribution line and a main line of the power distribution line, and the terminal node is located at a connection between the branch line of the power distribution line and a load device; The terminal node and the branch node constitute a section of the power distribution line. The section of the power distribution line includes a main line section and a branch line section. The line between the terminal node and the branch node is the branch line section, and the line between the branch node and the adjacent branch node is the main line section. Determine the degree of impact for each of the aforementioned segments, and based on the degree of impact, determine at least one target route; The step of determining the fault type based on the phase angle difference of the target line, and determining the target quadrant of the fault type in the four quadrants of the distribution network, includes: Determine the preset angle range in which the phase angle difference lies, and determine the user fault type corresponding to the target line through the preset angle range; Based on the user fault type, determine the target quadrant corresponding to the user type in the four quadrants of the distribution network.

8. The method of claim 7, wherein, Determining the degree of impact for each of the aforementioned segments, and determining at least one target route based on the degree of impact, includes: Obtain the transmission power of each segment at the time of the fault; Each transmission power is compared with a preset reference power, and the segments that exceed the preset reference power are marked to obtain the super reference power segments; The transmission power of each segment at the time of the fault is compared with a preset reference power, and the segments that do not exceed the preset reference power are marked to obtain the segments that do not exceed the reference power. The difference between each of the super-reference power segments and the preset reference power is determined to obtain the first power set; The difference between the power exceeding the preset reference power in each of the non-exceeding reference power segments is determined to obtain the second power set; The first power data set and the second power data set are used to form a matrix, wherein the row vectors in the matrix represent each segment, and the column vectors in the matrix are composed of the first power data set and the second power data set; Based on a pre-set risk assessment matrix, the degree of impact of each segment is determined; The degree of influence of each segment is multiplied by the power value of the corresponding segment in the matrix to obtain the degree of influence matrix; The segments in the influence degree matrix that exceed a preset threshold are marked, and the segments that exceed the preset threshold are taken as the target lines.

9. A machine-readable storage medium, characterized in that, The machine-readable storage medium stores instructions for causing the machine to execute the four-quadrant adaptive intelligent current protection method for distribution networks according to any one of claims 1 to 8.

10. A four-quadrant adaptive intelligent current protection system for a power distribution network, characterized by, include: The memory is configured to store instructions; as well as The processor is configured to retrieve the instructions from the memory and, when executing the instructions, to implement the four-quadrant adaptive intelligent current protection method for distribution networks according to any one of claims 1 to 8.

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