Active distribution line harmonic injection protection method based on control and protection coordination

Abstract

The present invention provides a harmonic injection protection method for an active distribution line based on control and protection coordination, which relates to a data processing technology. The method comprises obtaining a voltage time-series variation state of a distributed inverter-type new energy power grid-connected point, and generating an injection characteristic signal of the new energy power grid-connected point when the voltage time-series variation state meets a first preset requirement; combining the injection characteristic signal with a modulation signal controlled by an inverter; extracting electric energy characteristic information on both sides of the new energy power grid-connected point, obtaining an amplitude ratio of characteristic harmonic currents on both sides according to a preset analysis model, and determining a first fault position based on the amplitude ratio; analyzing a first device attribute of the new energy power grid-connected point at the first fault position, comparing the first device attribute with a second device attribute of other new energy power grid-connected points, and determining a high-risk protection area of ​​the distribution line.

Description

Technical Field

[0001] The present invention relates to data processing technology, and in particular to a harmonic injection protection method for active distribution lines based on control and protection collaboration. Background Art

[0002] Inverter-type distributed power sources such as photovoltaics and direct-drive wind turbines are increasingly being used in distribution networks. However, there are fundamental differences in fault characteristics between these types of power sources and traditional synchronous generators. Their short-circuit currents are affected by both internal control logic and external fault conditions, exhibiting unique phenomena such as amplitude limitation, phase controllability, and frequency deviation. In addition, the multi-point decentralized access mode of distributed power sources in distribution networks makes the distribution of short-circuit currents in the event of a fault complex, posing a severe challenge to traditional relay protection strategies based on single radial grids and synchronous generator characteristics.

[0003] In the existing technology, research has mostly focused on the improvement or innovation of protection criteria, striving to passively adapt to the complex fault characteristics of renewable energy power sources. However, given the variability of the external environment and the differences in control strategies, the short-circuit current characteristics of inverter-type distributed power sources during faults are difficult to accurately characterize with a single mathematical model, resulting in the newly proposed protection criteria being often limited to specific application scenarios and lacking universality.

[0004] Therefore, how to cross the boundaries of different fault scenarios and operating conditions when a power grid fault occurs, reliably identify faults inside and outside the area, accurately determine the fault location, and thus significantly improve the reliability and adaptability of protection has become an urgent problem that needs to be solved. Summary of the invention

[0005] The present invention provides an active distribution line harmonic injection protection method based on control and protection collaboration, which can, when a power grid fault occurs, cross the boundaries of different fault scenarios and operating conditions, reliably identify faults inside and outside the area, and accurately determine the fault location, thereby significantly improving the reliability and adaptability of protection.

[0006] A first aspect of the present invention provides an active distribution line harmonic injection protection method based on control and protection coordination, comprising:

[0007] Acquire a voltage time sequence change state of a distributed inverter-type new energy power grid-connected point, and generate an injection characteristic signal of the new energy power grid-connected point when the voltage time sequence change state meets a first preset requirement;

[0008] combining the injection characteristic signal with a modulation signal controlled by an inverter;

[0009] Extracting electric energy characteristic information on both sides of the new energy power supply grid connection point, obtaining the amplitude ratio of characteristic harmonic currents on both sides according to a preset analysis model, and determining the first fault location based on the amplitude ratio;

[0010] The first equipment attribute of the renewable energy power grid connection point at the first fault location is analyzed, and the first equipment attribute is compared with the second equipment attribute of other renewable energy power grid connection points to determine the high-risk protection area of ​​the distribution line.

[0011] Optionally, in a possible implementation of the first aspect, the acquiring the voltage time sequence change state of the distributed inverter-type new energy power grid-connected point, and generating an injection characteristic signal of the new energy power grid-connected point when the voltage time sequence change state meets a first preset requirement, includes:

[0012] Continuously acquiring the voltage time sequence change state of the distributed inverter-type new energy power supply grid connection point, and if it is determined that the voltage drop amplitude is less than a preset value, then determining that the voltage time sequence change state meets the first preset requirement;

[0013] The rated power information of the new energy power grid connection point is obtained, and a corresponding injection characteristic signal is generated based on the rated power information and a preset calculation formula. The injection characteristic signal includes at least a signal amplitude and a signal frequency.

[0014] Optionally, in a possible implementation manner of the first aspect, extracting electric energy characteristic information on both sides of the new energy power supply grid connection point, obtaining an amplitude ratio of characteristic harmonic currents on both sides according to a preset analysis model, and determining the first fault location based on the amplitude ratio includes:

[0015] Extracting the electric energy amplitudes on both sides of the new energy power supply grid connection point to obtain electric energy characteristic information, wherein the electric energy characteristic information includes inner electric energy information and outer electric energy information;

[0016] Compare the harmonic current amplitudes in the inner power information and the outer power information, take the corresponding amount with the larger amplitude as the numerator and the corresponding amount with the smaller amplitude as the denominator, and calculate the amplitude ratio of the characteristic harmonic currents on both sides of the line;

[0017] The amplitude ratio is numerically analyzed to determine the first fault location.

[0018] Optionally, in a possible implementation manner of the first aspect, performing numerical analysis on the amplitude ratio to determine the first fault location includes:

[0019] If the amplitude ratio is greater than 1, the first fault location is determined to be a fault within the line area, and auxiliary judgment processing is performed based on the phase angle difference between the harmonic current and the fundamental frequency current;

[0020] If the amplitude is not greater than 1, it is determined that the first fault location is a fault outside the line area or is empty.

[0021] Optionally, in a possible implementation manner of the first aspect, if the amplitude ratio is greater than 1, determining that the first fault location is a fault within the line area, and performing auxiliary judgment processing based on the phase angle difference between the harmonic current and the fundamental frequency current includes:

[0022] Obtaining a cosine value of a phase angle difference between a harmonic current and a fundamental frequency current of a line in the area, and obtaining a first numerical attribute of the cosine value, wherein the first numerical attribute includes a positive attribute or a negative attribute;

[0023] Obtaining a cosine value of a phase angle difference between a harmonic current and a fundamental frequency current of an out-of-area line, and obtaining a second numerical attribute of the cosine value, wherein the second numerical attribute includes a positive attribute or a negative attribute;

[0024] If the product of the first numerical attribute and the second numerical attribute is a negative number, it is determined to be an in-zone fault;

[0025] If the product of the first numerical attribute and the second numerical attribute is a positive number, it is determined to be an out-of-zone fault.

[0026] Optionally, in a possible implementation of the first aspect, analyzing a first device attribute of a new energy power supply grid connection point at a first fault location, comparing the first device attribute with a second device attribute of other new energy power supply grid connection points, and determining a high-risk protection area of ​​a distribution line includes:

[0027] If the first fault location is an in-area fault, obtaining a first device attribute of a new energy power supply grid connection point in the area;

[0028] Compare the first attribute information of the first device attribute with the second attribute information in the second device attribute of other new energy power grid connection points to obtain a device similarity coefficient;

[0029] If the equipment similarity coefficient is greater than a first preset value, the first state of the equipment in the area at the first fault location when the fault occurs is obtained, and the high-risk protection area of ​​the distribution line is determined based on the equipment similarity coefficient and the first state, the high-risk protection area is the area within the area, and the first state is the environmental state corresponding to the equipment in the area.

[0030] Optionally, in a possible implementation manner of the first aspect, comparing the first attribute information of the first device attribute with the second attribute information in the second device attribute of the other new energy power supply grid connection point to obtain the device similarity coefficient includes:

[0031] The attribute information includes fixed information and dynamic information, wherein the fixed information includes at least line length information and power generation information, and the dynamic information includes at least temperature information and humidity information;

[0032] Compare the first fixed information in the first attribute information with the second fixed information in the second attribute information to obtain a first similarity sub-coefficient;

[0033] Compare the first dynamic information in the first attribute information with the second dynamic information in the second attribute information to obtain a second similarity sub-coefficient;

[0034] A fused device similarity coefficient is obtained based on the first similarity sub-coefficient and the second similarity sub-coefficient.

[0035] Optionally, in a possible implementation manner of the first aspect, determining a high-risk protection area of ​​a distribution line based on the device similarity coefficient and the first state, wherein the high-risk protection area is an area within the zone, includes:

[0036] If the power generation information in the first fixed information is greater than the power generation information in the second fixed information, the power generation value in the first state is adjusted downward based on the device similarity coefficient;

[0037] If the power generation information in the first fixed information is less than the power generation information in the second fixed information, the power generation value in the first state is adjusted upward based on the device similarity coefficient.

[0038] Optionally, in a possible implementation of the first aspect, analyzing a first device attribute of a new energy power supply grid connection point at a first fault location, comparing the first device attribute with a second device attribute of other new energy power supply grid connection points, and determining a high-risk protection area of ​​a distribution line includes:

[0039] If the first fault location is an out-of-area fault, obtaining a first device attribute of a new energy power grid connection point in the area and a first line attribute of a line where the new energy power grid connection point is located;

[0040] Compare the first attribute information of the first device attribute with the second attribute information in the second device attribute of other new energy power grid connection points to obtain a device similarity coefficient;

[0041] Compare the first line information of the first line attribute with the second line information in the second line attribute of other new energy power grid connection points to obtain a line similarity coefficient;

[0042] The device similarity coefficient and the line similarity coefficient are merged to obtain a total similarity coefficient. If the total similarity coefficient is greater than a second preset value, the second states of the equipment within the zone and the equipment outside the zone at the first fault location when the fault occurs are obtained. Based on the device similarity coefficient and the second state, the high-risk protection area of ​​the distribution line is determined, and the high-risk protection area is the area outside the zone.

[0043] Optionally, in a possible implementation manner of the first aspect, if the first fault location is an out-of-region fault, obtaining a first device attribute of a new energy power grid connection point in the region and a first line attribute of a line where the new energy power grid connection point is located includes:

[0044] Taking the grid connection point of the new energy power source as the initial point, the preset distances on both sides of the line are extended to obtain the line where it is located;

[0045] The grid-connected rated power of other coordinated new energy power grid-connected points in the line and the rated load of the load are obtained to obtain the first line attribute.

[0046] Optionally, in a possible implementation manner of the first aspect, comparing the first line information of the first line attribute with the second line information in the second line attribute of the other new energy power supply grid connection point to obtain the line similarity coefficient includes:

[0047] Compare the first number of coordinated new energy power grid connection points and the first grid-connected rated power in the first line information with the second number of coordinated new energy power grid connection points and the second grid-connected rated power in the second line information to obtain a first coordination coefficient;

[0048] Compare a first rated load of a first load in the first line information with a second rated load of a second load in the second line information to obtain a second coordination coefficient;

[0049] A line similarity coefficient is obtained based on the first cooperation coefficient and the second cooperation coefficient.

[0050] Optionally, in a possible implementation manner of the first aspect, obtaining the second state of the in-zone device and the out-zone device at the first fault location when the fault occurs, and determining the high-risk protection area of ​​the distribution line based on the device similarity coefficient and the second state, wherein the high-risk protection area is the out-zone area, includes:

[0051] The second state of the in-zone equipment and the out-zone equipment at the first fault location when the fault occurs is obtained, wherein the second state at least includes the rated power in the zone, the rated power outside the zone, and the environmental state.

[0052] According to a second aspect of the present invention, a storage medium is provided, in which a computer program is stored. When the computer program is executed by a processor, it is used to implement the method of the first aspect of the present invention and various possible designs of the first aspect.

[0053] The beneficial effects of the present invention are as follows:

[0054] 1. When a fault occurs in the power grid, the present invention can cross the boundaries of different fault scenarios and operating conditions, reliably identify faults inside and outside the area, and accurately determine the fault location, thereby significantly improving the reliability and adaptability of protection. The present invention can achieve real-time monitoring of the grid connection points of new energy power sources, accurate fault location, and efficient fault protection, and can identify high-risk protection areas in advance, thereby improving the overall protection level of the grid-connected distribution lines of new energy power sources.

[0055] 2. The present invention can accurately detect faults through real-time monitoring. Among them, by continuously acquiring the voltage time-series change state, the voltage condition of the new energy power grid connection point can be monitored in real time, and a characteristic signal can be generated when the preset conditions are met, which ensures the timeliness and accuracy of harmonic injection, thereby improving the accuracy of fault location. In addition, the present invention can quickly and accurately determine the fault location and distinguish between in-zone faults and out-of-zone faults by extracting and analyzing the electric energy characteristic information on both sides of the new energy power grid connection point and using a more complex comparison algorithm, which can effectively avoid the short-circuit current problem that occurs in traditional methods when processing distributed inverter power supplies, and improve the reliability of protection actions.

[0056] 3. The present invention can determine the high-risk protection area of ​​the distribution line in advance by analyzing the fault location and its equipment properties and comparing the properties of similar equipment and lines, so that targeted prevention and protection measures can be taken to ensure the safe and stable operation of the distribution line. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] Figure 1 A flow chart of a harmonic injection protection method for active distribution lines based on control and protection collaboration provided by the present invention. DETAILED DESCRIPTION

[0058] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0059] The terms "first", "second", "third", "fourth", etc. (if any) in the description and claims of the present invention and the above drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the numbers used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in sequences other than those illustrated or described herein.

[0060] It should be understood that in various embodiments of the present invention, the size of the sequence number of each process does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0061] It should be understood that in the present invention, "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or apparatus comprising a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to these processes, methods, products or apparatuses.

[0062] It should be understood that in the present invention, "plurality" refers to two or more than two. "And / or" is merely a description of the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. The character " / " generally indicates that the objects associated before and after are in an "or" relationship. "Contains A, B and C", "Contains A, B, C" means that A, B, and C are all included, "Contains A, B or C" means that one of A, B, and C is included, and "Contains A, B and / or C" means that any one, any two, or any three of A, B, and C are included.

[0063] It should be understood that in the present invention, "B corresponding to A", "B corresponding to A", "A corresponds to B" or "B corresponds to A" means that B is associated with A and B can be determined based on A. Determining B based on A does not mean determining B based only on A, but B can also be determined based on A and / or other information. A and B match when the similarity between A and B is greater than or equal to a preset threshold.

[0064] Depending on the context, "if" as used herein may be interpreted as "when" or "when" or "in response to determining" or "in response to detecting."

[0065] The technical solution of the present invention is described in detail with specific embodiments below. The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described in detail in some embodiments.

[0066] like Figure 1 As shown, it is a flow chart of a harmonic injection protection method for active distribution lines based on control and protection coordination provided by the present invention, and the harmonic injection protection method for active distribution lines based on control and protection coordination includes:

[0067] S1, obtaining a voltage time sequence change state of a distributed inverter-type new energy power grid-connected point, and generating an injection characteristic signal of the new energy power grid-connected point when the voltage time sequence change state meets a first preset requirement.

[0068] It should be noted that in modern power systems, with the widespread application of distributed inverter-type new energy power sources, distribution line protection and fault location have become a complex and important issue. Traditional protection methods may not be able to meet the protection needs in the new energy power grid-connected environment. Therefore, the active distribution line harmonic injection protection method with coordinated control and protection can be used to improve the protection and fault location capabilities of distribution lines.

[0069] It can be understood that by obtaining the voltage changes of the grid-connected points of renewable energy power sources, it is ensured that the voltage changes of the grid-connected points can be detected in a timely manner. When the triggering conditions of the protection mechanism are met, an injection characteristic signal is generated for subsequent combination with the modulation signal to improve the accuracy and effectiveness of harmonic injection, so as to accurately determine the fault location in the future and thus perform precise protection.

[0070] Among them, the new energy power grid connection point is the location point where the new energy power source is connected to other power grids, for example, the equipment location point where the photovoltaic power generation source is connected to the municipal power grid. The voltage timing change state is the voltage state of the voltage at the power grid connection point that changes with time. The first preset requirement is a pre-set voltage requirement for generating an injection characteristic signal. For example, when the voltage is less than a preset voltage value, it is determined to meet the first preset requirement. The injection characteristic signal is a characteristic signal for injecting harmonics into the new distribution line.

[0071] Through the above implementation, the present invention can generate a corresponding injection characteristic signal so as to be subsequently combined with a modulation signal to determine the location of a fault in the corresponding power grid.

[0072] In some embodiments, the specific implementation of step S1 (obtaining the voltage time sequence change state of the distributed inverter-type new energy power grid-connected point, and generating the injection characteristic signal of the new energy power grid-connected point when the voltage time sequence change state meets the first preset requirement) includes:

[0073] S11, continuously acquiring the voltage time sequence change state of the distributed inverter-type new energy power supply grid connection point, and if it is determined that the voltage drop amplitude is less than a preset value, then it is determined that the voltage time sequence change state meets the first preset requirement.

[0074] It can be understood that the voltage timing change state of the distributed inverter-type new energy power grid connection point is continuously obtained to realize real-time monitoring of the voltage state. When the voltage drop is less than the preset drop reference value, it can be determined that the voltage timing change state meets the first preset requirement, so as to subsequently generate the corresponding injection characteristic signal.

[0075] The voltage drop amplitude is the amplitude value of the voltage drop, and the preset value is a preset reference value of the voltage drop, which is preset.

[0076] S12, obtaining rated power information of the new energy power grid connection point, and generating a corresponding injection characteristic signal based on the rated power information and a preset calculation formula, wherein the injection characteristic signal at least includes a signal amplitude and a signal frequency.

[0077] It can be understood that after obtaining the rated power signal corresponding to the new energy power grid connection point, the rated power information can be input into the preset calculation formula for calculation to generate the corresponding injection characteristic signal, wherein the injection characteristic signal at least includes the characteristics of signal amplitude and signal frequency, so that the signal amplitude and signal frequency corresponding to the injection characteristic signal can be subsequently combined with the modulation signal to analyze the corresponding fault location.

[0078] Among them, the rated power information is the rated power corresponding to the new energy power grid connection point, and the preset calculation formula is a preset signal formula for calculating the injected characteristic signal.

[0079] S2, combining the injection characteristic signal with a modulation signal controlled by an inverter.

[0080] It can be understood that the accuracy and effectiveness of harmonic injection can be improved by combining the characteristic signal with the modulation signal.

[0081] Among them, the characteristic signal is injected into the modulation signal controlled by the inverter, and the mathematical expression of the injected characteristic harmonic amount is:

[0082] ,

[0083] In the formula, is the amplitude corresponding to the characteristic harmonic, is the amplitude of the injected harmonics, is the initial phase angle of the injected harmonic quantity, is the frequency of the injected harmonic quantity, is the frequency of the corresponding modulation signal, and regarding the values ​​of harmonic amplitude, initial phase angle and frequency, considering that the overcurrent capacity of the grid-connected inverter is limited and the injection of harmonics may affect the transient control of the inverter, the amplitude of the injected characteristic signal proposed in the present invention is Take it as 10% of the rated current of the photovoltaic power source, the frequency of the harmonic Taken as 200Hz, in order to ensure that the harmonic active injection protection mentioned later can effectively distinguish between internal and external faults, the initial phase angle of the harmonic characteristic signal here is The value is taken to be the same as the initial phase angle of the fundamental frequency voltage at the grid connection point.

[0084] S3, extracting electric energy characteristic information on both sides of the new energy power supply grid connection point, obtaining the amplitude ratio of characteristic harmonic currents on both sides according to a preset analysis model, and determining the first fault location based on the amplitude ratio.

[0085] It can be understood that by extracting the electric energy characteristic information on both sides of the new energy power grid connection point and comparing the amplitudes of the characteristic harmonic currents on both sides according to a preset model, the fault point can be accurately located.

[0086] Among them, the power characteristic information is the power information corresponding to the lines on both sides of the new energy power grid connection point, and the preset model is a pre-set calculation model, such as the FFT algorithm model to extract the amplitude of the characteristic harmonic current and , phase angle of characteristic harmonic current and , fundamental frequency current phase angle and ,in, , and They are the characteristic harmonic current amplitude, harmonic current phase angle and fundamental frequency current phase angle on the inverter power supply side. , and They correspond to the characteristic harmonic current amplitude, harmonic current phase angle and fundamental frequency current phase angle on the system side respectively. The amplitude ratio is the ratio of the amplitudes of the characteristic harmonic currents on both sides. The first fault position is the position where the fault occurs in the grid-connected line.

[0087] In some embodiments, the specific implementation of step S3 (the extraction of electric energy characteristic information on both sides of the new energy power supply grid connection point, obtaining the amplitude ratio of characteristic harmonic currents on both sides according to a preset analysis model ratio, and determining the first fault location based on the amplitude ratio) includes:

[0088] S31, extracting the electric energy amplitudes on both sides of the new energy power supply grid connection point to obtain electric energy characteristic information, wherein the electric energy characteristic information includes inner electric energy information and outer electric energy information.

[0089] It should be noted that a large number of sick anchor points appear in the grid connection of new energy power sources. Therefore, when troubleshooting the location of the fault point, it is necessary to quickly determine the location points of the corresponding in-zone faults and out-of-zone faults. Thus, the electric energy characteristic information on both sides of the grid connection point of the new energy power source can be determined to distinguish the corresponding fault point location later. Among them, in-zone and out-of-zone faults are two situations in the power system. In-zone faults refer to faults that occur inside the power system protected by the relay protection. For example, the fault may occur in power system components such as generators, transformers, cable lines, and switchgear. Out-of-zone faults refer to faults that occur outside the scope of the power system protected by the relay protection. For example, the fault may occur in transmission lines, power supply systems outside substations, equipment that is not directly connected to the power system, etc.

[0090] It can be understood that the electric energy amplitude is a characteristic amplitude related to electric energy, and accurate electric energy characteristic information is obtained by extracting the electric energy amplitude, so as to subsequently determine the corresponding first fault position.

[0091] Among them, the electric energy characteristic information includes inner electric energy information and outer electric energy information. The inner electric energy information is the electric energy characteristic parameter information of the corresponding lines within the area, and the outer electric energy information is the corresponding electric energy characteristic parameter information outside the area.

[0092] S32, compare the harmonic current amplitudes in the inner power information and the outer power information, take the corresponding amount with the larger amplitude as the numerator and the corresponding amount with the smaller amplitude as the denominator, and calculate the amplitude ratio of the characteristic harmonic currents on both sides of the line.

[0093] It can be understood that the amplitude ratio of the harmonic current is calculated by taking the larger amplitude as the numerator and the smaller amplitude as the denominator, for example: .

[0094] It is not difficult to understand that after calculating the amplitude ratio of the characteristic harmonic currents on both sides of the line, the corresponding first fault position can be determined through subsequent analysis of the amplitude ratio so that timely measures can be taken to protect the line.

[0095] S33, performing numerical analysis on the amplitude ratio to determine a first fault location.

[0096] It can be understood that when a fault occurs within the line area, the harmonic current amplitude ratio on both sides of the line will usually be greater than 1; when a fault occurs outside the line area or no fault occurs, the harmonic current amplitude ratio on both sides of the line is almost close to 1. In addition, unlike the traditional current differential protection criterion, the protection criterion proposed in the present invention judges the faults inside and outside the area according to the harmonic current amplitude ratio on both sides of the line. This can avoid the problem that the short-circuit current of the distributed inverter power supply is affected by the light illumination (or wind speed) and the like, resulting in its fault characteristics being unclear, thereby ensuring that the proposed protection criterion has good applicability in various fault scenarios and working conditions after a high proportion of distributed inverter-type new energy is connected.

[0097] In some embodiments, a specific implementation of step S33 (the numerical analysis of the amplitude ratio to determine the first fault location) includes:

[0098] S331: If the amplitude ratio is greater than 1, the first fault location is determined to be a fault within the line area, and auxiliary judgment processing is performed based on the phase angle difference between the harmonic current and the fundamental frequency current.

[0099] It can be understood that when the calculated amplitude ratio is greater than 1, it can be explained that the corresponding first fault location belongs to an intra-zone fault, and the phase angle difference between the harmonic current and the fundamental frequency current can be used for auxiliary judgment to further improve the accuracy of determining the corresponding first fault location and improve the reliability of the proposed protection action.

[0100] The phase angle difference is the phase angle difference between the harmonic current and the fundamental frequency current.

[0101] In some embodiments, the specific implementation of step S331 (if the amplitude ratio is greater than 1, the first fault location is determined to be a fault within the line area, and auxiliary judgment processing is performed based on the phase angle difference between the harmonic current and the fundamental frequency current) includes:

[0102] S3311, obtaining a cosine value of a phase difference between a harmonic current and a fundamental frequency current of a line in the area, and obtaining a first numerical attribute of the cosine value, wherein the first numerical attribute includes a positive attribute or a negative attribute.

[0103] It should be noted that the fault direction can be identified by calculating the cosine value of the phase angle difference between the harmonic current and the fundamental frequency current on the line and comparing the positive and negative relationship of the cosine value of the phase angle difference on both sides of the line.

[0104] It can be understood that the first numerical attribute is the numerical attribute of the cosine value calculated corresponding to the line in the area, including a positive attribute or a negative attribute. When the cosine value is a positive number, it corresponds to a positive attribute, and when the cosine value is a negative number, it corresponds to a negative attribute.

[0105] S3312, obtaining a cosine value of a phase angle difference between a harmonic current and a fundamental frequency current of an out-of-zone line, and obtaining a second numerical attribute of the cosine value, wherein the second numerical attribute includes a positive attribute or a negative attribute.

[0106] It can be understood that the second numerical attribute is the numerical attribute of the cosine value calculated corresponding to the out-of-zone line, including a positive attribute or a negative attribute. When the cosine value is a positive number, it corresponds to a positive attribute, and when the cosine value is a negative number, it corresponds to a negative attribute.

[0107] S3313: If the product of the first numerical attribute and the second numerical attribute is a negative number, it is determined to be an in-zone fault.

[0108] It should be noted that when an in-area fault occurs, the harmonic current flowing through the two sides of the line is mainly provided by the photovoltaic power station, wherein the direction of the harmonic current flowing through the distributed power supply side protection is from the bus to the line, while the direction of the harmonic current flowing through the system side protection is from the bus to the line. Therefore, the phase angles of the harmonic currents flowing through the protections on both sides of the line are opposite, that is, one is a positive acute angle and the other is a negative acute angle or obtuse angle. However, the fundamental frequency current flowing through the protections on both sides of the line is provided by the system power supply and the photovoltaic power station respectively, and the current flows from the bus to the line. Therefore, the values ​​of the phase angles of the fundamental frequency currents flowing through the protections on both sides of the line are basically the same, that is, both are positive angles or both are negative angles.

[0109] It can be understood that when there is an intra-zone fault, the phase angle difference between the harmonic current and the fundamental current on both sides of the line falls on the positive half-axis area of ​​the plane rectangular coordinate system X on one side and on the negative half-axis area of ​​X on the other side. This makes the cosine values ​​of the phase angle difference between the harmonic current and the fundamental frequency current measured at the protection installations on both sides of the line opposite in sign, that is, the product of the values ​​on both sides is -1, which is a negative number, and it can be determined as an intra-zone fault.

[0110] S3314: If the product of the first numerical attribute and the second numerical attribute is a positive number, it is determined to be an out-of-zone fault.

[0111] It should be noted that when an out-of-zone fault occurs, the phase angles of the fundamental frequency currents flowing through the protections on both sides of the line are opposite, and the phase angles of the harmonic frequency currents flowing through the protections on both sides of the line are also opposite. Therefore, the phase angle difference between the fundamental frequency currents and the harmonic currents flowing through the protections on both sides of the line is also opposite.

[0112] It can be understood that when an out-of-zone fault occurs, the phase difference between the harmonic current and the fundamental current on both sides of the line falls in the same X-axis area, which makes the cosine values ​​of the phase difference between the harmonic current and the fundamental frequency current measured at the protection installations on both sides of the line the same in sign, that is, the product of the values ​​on both sides is 1, which is a positive number, and it can be determined as an out-of-zone fault.

[0113] S332: If the amplitude is not greater than 1, it is determined that the first fault location is a fault outside the line area or is empty.

[0114] It can be understood that when the amplitude is not greater than 1, it can be determined that the fault occurring in the corresponding line is a fault outside the line area or is empty.

[0115] S4, analyzing the first equipment attribute of the renewable energy power grid connection point at the first fault location, comparing the first equipment attribute with the second equipment attribute of other renewable energy power grid connection points, and determining the high-risk protection area of ​​the distribution line.

[0116] It should be noted that the failure of the new energy power supply may be an intra-regional failure or an extra-regional failure. For example, when it is an intra-regional failure, the corresponding new energy power plant fails inside, and when the extra-regional failure is a failure in the mains power line, the failure may be related to the grid-connected status, power generation or power consumption. Therefore, it can be determined that the new energy grid connection point or distribution line with a similar structure to the current one may also fail. Therefore, through comparative analysis, the corresponding structural lines or equipment can be prevented from failure in advance.

[0117] It can be understood that the first device attributes of the new energy power grid connection point at the first fault location are analyzed, and then the first device attributes are compared with the second device attributes of other new energy power grid connection points, so as to determine the high-risk protection area corresponding to the distribution line, so as to provide timely protection for the high-risk protection area and ensure the normal operation of the line.

[0118] Among them, the first device attribute is the attribute of the equipment at the corresponding grid connection point, such as solar power generation attributes, wind power generation attributes, etc. The second device attribute is the attribute of the equipment at other new energy power grid connection points, and the high-risk protection area is a high-risk area to be protected.

[0119] In some embodiments, a specific implementation of step S4 (analyzing the first device attribute of the new energy power grid connection point at the first fault location, comparing the first device attribute with the second device attribute of other new energy power grid connection points, and determining the high-risk protection area of ​​the distribution line) includes:

[0120] S41: If the first fault location is an in-area fault, obtain a first device attribute of a new energy power grid connection point in the area.

[0121] It can be understood that when the first fault location is an intra-area fault, that is, an equipment fault before the corresponding new energy power grid connection point, the first equipment attribute of the new energy power grid connection point in the corresponding area can be obtained for subsequent similarity comparison to determine a power grid distribution environment with high similarity.

[0122] S42, comparing the first attribute information of the first device attribute with the second attribute information in the second device attribute of other new energy power grid-connected points to obtain a device similarity coefficient.

[0123] It is understandable that the corresponding first attribute information and second attribute information may be the same, for example, both are wind power generation or photovoltaic power generation, so that the corresponding attribute information can be calculated to obtain the equipment similarity coefficient in order to determine the high-risk protection area of ​​the entire distribution line.

[0124] Among them, the equipment similarity coefficient is the similarity coefficient between different power grid equipment.

[0125] In some embodiments, the specific implementation of step S42 (comparing the first attribute information of the first device attribute with the second attribute information in the second device attribute of other new energy power supply grid connection points to obtain the device similarity coefficient) includes:

[0126] S421, the attribute information includes fixed information and dynamic information, the fixed information includes at least line length information and power generation information, and the dynamic information includes at least temperature information and humidity information.

[0127] It can be understood that fixed information is relatively fixed information of the equipment, such as the line length and power generation of new energy. Therefore, the fixed information at least includes line length information and power generation information.

[0128] Among them, since the environment in which the device is located will constantly change, for example, the temperature and humidity of the corresponding environment, the dynamic information at least also includes temperature information and humidity information.

[0129] Through the above implementation, the attribute information is classified so that similarity calculation can be performed according to the categories later, thereby achieving a comprehensive evaluation of the similarity between different power grid devices.

[0130] S422: Compare the first fixed information in the first attribute information with the second fixed information in the second attribute information to obtain a first similarity sub-coefficient.

[0131] It can be understood that the first fixed information is the line length and power generation of the first device, the second fixed information is the line length and power generation of the equipment at other new energy power grid points, and the first similarity sub-coefficient is the similarity coefficient after comparing the fixed information.

[0132] S423: Compare the first dynamic information in the first attribute information with the second dynamic information in the second attribute information to obtain a second similarity sub-coefficient.

[0133] It can be understood that the first dynamic information is the dynamic information corresponding to the first device, the second dynamic information is the dynamic information of the devices at other new energy power grid points, and the second similarity sub-coefficient is the similarity coefficient after comparing the dynamic information.

[0134] S424: Obtain a fused device similarity coefficient based on the first similarity sub-coefficient and the second similarity sub-coefficient.

[0135] The device similarity coefficient is calculated by the following formula:

[0136] ,

[0137] in, is the equipment similarity coefficient, is the line length information in the first fixed information, is the line length information in the first fixed information, is the length coefficient value, is the power generation information in the first fixed information, is the power generation information in the second fixed information, is the power coefficient value, To fix the similarity weight, For the The first dynamic information of the dynamic dimension, For the The second dynamic information of the dynamic dimension, is the upper limit of the dynamic dimension, For the Similarity weights of dynamic dimensions, is the dynamic similarity weight.

[0138] It can be understood that when the corresponding line length and power generation in the fixed information are closer, the corresponding first similarity sub-coefficient will be larger. At the same time, when the corresponding dynamic environment information is closer, the second similarity sub-coefficient will also be larger. Therefore, the larger the equipment similarity coefficient is, the higher the similarity of the corresponding equipment is, and the corresponding high-risk protection area can be determined. Among them, the length coefficient value is the similarity weight coefficient value corresponding to the line length, and the power coefficient value is the similarity weight coefficient value corresponding to the power generation. No. The similarity weight of each dynamic dimension is the similarity comparison weight value corresponding to each type of information in the dynamic information. The weight value corresponding to the dynamic information is preset manually.

[0139] It is not difficult to understand that since there are many influencing factors in the environment, that is, there may be more than two pieces of information in the dynamic dimension, and there may be multiple ones, such as temperature, humidity, pressure, etc., so that all dynamic influences can be summed up and calculated, so that the final device similarity coefficient is more accurate.

[0140] S43, if the equipment similarity coefficient is greater than a first preset value, obtain the first state of the equipment in the area at the first fault location when the fault occurs, and determine the high-risk protection area of ​​the distribution line based on the equipment similarity coefficient and the first state, the high-risk protection area is the area within the area, and the first state is the environmental state corresponding to the equipment in the area.

[0141] It is understandable that the corresponding properties between different devices are the same, but the corresponding states may also be different. For example, if one side corresponds to continuous high temperature and the other side has high humidity, the states are different and may not cause corresponding hazards. Therefore, the high-risk protection area of ​​the distribution line can be determined based on the equipment similarity coefficient and the first state, that is, the current high-risk protection area is the area within the zone.

[0142] The in-zone device is a device that belongs to the protected area, and the first state is a state corresponding to the in-zone device, such as a temperature state, a humidity state, and the like.

[0143] In some embodiments, a specific implementation of step S43 (determining a high-risk protection area of ​​the distribution line based on the device similarity coefficient and the first state, wherein the high-risk protection area is an area within the zone) includes:

[0144] S431: If the power generation information in the first fixed information is greater than the power generation information in the second fixed information, the power generation value in the first state is adjusted downward based on the device similarity coefficient.

[0145] It should be noted that the information of two regions may be similar, but not exactly the same. Therefore, it is necessary to compare the relevant data. For example, the number of solar panels in two regions is different. One region has 10 and the other has 9. The two are similar but still different. Therefore, the related information values ​​need to be adjusted according to the actual degree of similarity.

[0146] It can be understood that when the line length information in the first fixed information is greater than the line length information in the second fixed information, the corresponding power loss of the first device will be greater than the power loss of the second device, so that the power generation value in the first state can be adjusted downward by the equipment similarity coefficient to obtain the adjusted value, so as to determine the high-risk protection area corresponding to the fault according to the adjusted value.

[0147] S432: If the power generation information in the first fixed information is less than the power generation information in the second fixed information, the power generation value in the first state is adjusted upward based on the device similarity coefficient.

[0148] It can be understood that when the line length information in the first fixed information is smaller than the line length information in the second fixed information, the corresponding power loss of the first device will be smaller than the corresponding power loss of the second device. Thus, the power generation value in the first state can be adjusted upward through the device similarity coefficient to obtain the adjusted value, so as to determine the high-risk protection area corresponding to the fault according to the adjusted value.

[0149] The adjusted power generation value in the first state is calculated by the following formula:

[0150] ,

[0151] in, is the power generation value in the first state after adjustment, is the power generation value in the first state before adjustment, is the normalized value.

[0152] It can be understood that when the line length information in the first fixed information is greater than or less than the line length information in the second fixed information, the power generation will be adjusted according to the equipment similarity coefficient, and the greater the difference between the line length information in the first fixed information and the line length information in the second fixed information, the smaller the corresponding equipment similarity coefficient, and thus the higher the proportion of adjustment of the power generation information.

[0153] in, It is a normalized value, which can be a normalized processing value set in advance manually.

[0154] In some embodiments, a specific implementation of step S4 (analyzing the first device attribute of the new energy power grid connection point at the first fault location, comparing the first device attribute with the second device attribute of other new energy power grid connection points, and determining the high-risk protection area of ​​the distribution line) includes:

[0155] S44: If the first fault location is an out-of-area fault, obtain a first device attribute of the renewable energy power grid connection point in the area and a first line attribute of the line where the renewable energy power grid connection point is located.

[0156] It can be understood that when the first fault location belongs to an out-of-zone fault, it is necessary to consider not only the status of the connected internal new energy, but also the status of the corresponding AC power line outside the corresponding zone. Therefore, it is necessary to obtain the first device attributes of the new energy power grid connection point in the zone and the first line attributes of the line where the new energy power grid connection point is located, so as to improve the accuracy of determining the high-risk protection area.

[0157] Among them, the first line attribute is the attribute information of the line where the new energy power grid connection point is located.

[0158] In some embodiments, a specific implementation of step S44 (if the first fault location is an out-of-region fault, obtaining a first device attribute of a new energy power grid connection point in the region and a first line attribute of a line where the new energy power grid connection point is located) includes:

[0159] S441, taking the grid connection point of the new energy power source as the initial point, extending to preset distances on both sides of the line to obtain the line where it is located.

[0160] It is understandable that the new energy power grid connection point is used as the initial point so as to extend a preset distance to both sides of the line to determine the power grid line where the corresponding new energy power equipment is located.

[0161] The preset distance is a preset line length distance.

[0162] S442, obtaining the grid-connected rated power of other coordinated new energy power grid-connected points in the line and the rated load of the load to obtain the first line attribute.

[0163] It is understandable that the corresponding power grid line may supply electricity to other areas. Therefore, the grid-connected rated power of other coordinated new energy power grid-connected points in the line and the rated load of the load can be obtained to obtain the first line attributes and thereby determine the corresponding high-risk protection area.

[0164] Among them, the grid-connected rated power is the rated power generated by the grid-connected new energy power source, the rated load is the rated power load in the corresponding line, and the first line attribute is the information attribute of the corresponding line, including the grid-connected rated power and the rated load of the load.

[0165] S45, comparing the first attribute information of the first device attribute with the second attribute information in the second device attribute of other new energy power supply grid-connected points to obtain a device similarity coefficient.

[0166] It can be understood that the first attribute information is the line attribute information corresponding to the first device attribute, the second attribute information is the line attribute information corresponding to the second device attribute of other new energy power grid connection points, and the equipment similarity coefficient is the similarity coefficient of the equipment corresponding to the new energy power source. The calculation method is consistent with the above logic and will not be repeated here.

[0167] S46, comparing the first line information of the first line attribute with the second line information in the second line attribute of the other new energy power grid connection point to obtain a line similarity coefficient.

[0168] It can be understood that the first line information of the first line attribute is compared with the second line information in the second line attribute of other new energy power grid connection points to obtain the line similarity coefficient.

[0169] The line similarity coefficient is the similarity coefficient value corresponding to the line information.

[0170] In some embodiments, the specific implementation of step S46 (comparing the first line information of the first line attribute with the second line information in the second line attribute of the other new energy power supply grid connection point to obtain the line similarity coefficient) includes:

[0171] S461, compare the first number of coordinated new energy power grid-connected points and the first grid-connected rated power in the first line information with the second number of coordinated new energy power grid-connected points and the second grid-connected rated power in the second line information to obtain a first coordination coefficient.

[0172] It can be understood that the first quantity is the number of coordinated new energy power grid connection points in the first line information, the first grid-connected rated power is the rated power corresponding to the coordinated new energy power grid connection points in the first line information, the second quantity is the attribute of the coordinated new energy power grid connection points in the second line information, the second grid-connected rated power is the rated power corresponding to the coordinated new energy power grid connection points in the second line information, and the first coordination coefficient is the coefficient value of the similarity comparison of corresponding information in the first line information and the second line information.

[0173] S462: Compare the first rated load of the first load in the first line information with the second rated load of the second load in the second line information to obtain a second coordination coefficient.

[0174] It can be understood that the first load is the corresponding load in the first line, the first rated load is the load power corresponding to the first load in the first line information, the second load is the corresponding load in the second line, the second rated load is the load power corresponding to the second load in the second line information, and the second coordination coefficient is the similarity comparison coefficient value between the first rated load and the second rated load.

[0175] Through the above implementation, the present invention can determine the second coordination coefficient, so as to obtain the line similarity coefficient later, thereby determining the corresponding high-risk protection area.

[0176] S463: Obtain a line similarity coefficient based on the first coordination coefficient and the second coordination coefficient.

[0177] It can be understood that the corresponding line similarity coefficient can be calculated based on the first coordination coefficient and the second coordination coefficient to determine the corresponding high-risk protection area, wherein the closer the corresponding information values ​​are, the higher the corresponding similarity coefficient is, which indicates that the similarity between different lines is higher.

[0178] The line similarity coefficient is calculated by the following formula:

[0179] ,

[0180] in, is the line similarity coefficient, The first number of new energy power grid connection points, The second number of new energy power grid connection points, is the quantity coefficient weight, is the first grid-connected rated capacity, is the second grid-connected rated capacity, is the rated power coefficient value, is the first collaborative weight, is the first rated load of the first load, is the second rated load of the second load, is the rated load factor value, is the second collaborative weight.

[0181] Understandably, is the first synergy coefficient, is the second coordination coefficient. Thus, when the first coordination coefficient and the second coordination coefficient are higher, the corresponding line similarity coefficient r will also increase accordingly, and it can be determined that the corresponding lines are more similar. Conversely, when the first coordination coefficient and the second coordination coefficient are lower, the corresponding line similarity coefficient r will also decrease accordingly, and it can be determined that the corresponding lines are more dissimilar.

[0182] Among them, the quantity coefficient weight is the similarity weight value set for the similarity of the number of grid connection points, the rated power coefficient value is the weight coefficient value set for the similarity of the rated power, the first coordination weight is the similarity weight value corresponding to the first coordination coefficient in the calculation of the line similarity coefficient, and the second coordination weight is the similarity weight value corresponding to the second coordination coefficient in the calculation of the line similarity coefficient, all of which are pre-set weight values.

[0183] S47, the device similarity coefficient and the line similarity coefficient are merged to obtain a total similarity coefficient. If the total similarity coefficient is greater than a second preset value, the second state of the equipment within the zone and the equipment outside the zone when the first fault location occurs is obtained, and the high-risk protection area of ​​the distribution line is determined based on the device similarity coefficient and the second state, and the high-risk protection area is the area outside the zone.

[0184] It can be understood that when the total similarity coefficient is greater than the second preset value, it can be said that the corresponding lines are relatively close, and the second state corresponding to the first fault location in the in-zone device and the out-zone device can be obtained to determine the high-risk protection area.

[0185] Among them, the total similarity coefficient is the fusion value of the equipment similarity coefficient and the line similarity coefficient. The second preset value is the benchmark value for judging the total similarity coefficient, which is preset manually. The second state is the equipment state of the in-zone equipment and the out-zone equipment when the first fault location occurs. The in-zone equipment is the equipment classified as the in-zone power grid, and the out-zone equipment is the equipment classified as the out-of-zone power grid.

[0186] In some embodiments, the specific implementation method of step S47 (the step of obtaining the second state of the equipment within the zone and the equipment outside the zone when the first fault location occurs, and determining the high-risk protection area of ​​the distribution line based on the equipment similarity coefficient and the second state, wherein the high-risk protection area is the area outside the zone) includes: obtaining the second state of the equipment within the zone and the equipment outside the zone when the first fault location occurs, wherein the second state includes at least the rated power within the zone, the rated power outside the zone, and the environmental state.

[0187] It can be understood that the second state includes at least the rated power within the zone, the rated power outside the zone and the environmental state, wherein the environmental state is the environmental information of the corresponding equipment inside and outside the zone, such as temperature, humidity, etc., so as to improve the accuracy of the calculation results by performing similarity comparison between the inside and outside of the zone through comprehensive information.

[0188] The present invention also provides a storage medium, in which a computer program is stored. When the computer program is executed by a processor, it is used to implement the methods provided by the various embodiments described above.

[0189] Among them, the storage medium can be a computer storage medium or a communication medium. The communication medium includes any medium that facilitates the transmission of a computer program from one place to another. The computer storage medium can be any available medium that can be accessed by a general-purpose or special-purpose computer. For example, the storage medium is coupled to the processor so that the processor can read information from the storage medium and write information to the storage medium. Of course, the storage medium can also be a component of the processor. The processor and the storage medium can be located in an application-specific integrated circuit (Application Specific Integrated Circuits, referred to as: ASIC). In addition, the ASIC can be located in a user device. Of course, the processor and the storage medium can also exist in a communication device as discrete components. The storage medium can be a read-only memory (ROM), a random access memory (RAM), a CD-ROM, a magnetic tape, a floppy disk, and an optical data storage device, etc.

[0190] The present invention also provides a program product, which includes an execution instruction, which is stored in a storage medium. At least one processor of a device can read the execution instruction from the storage medium, and at least one processor executes the execution instruction so that the device implements the methods provided in the above various embodiments.

[0191] In the above-mentioned terminal or server embodiments, it should be understood that the processor may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), etc. A general-purpose processor may be a microprocessor or any conventional processor. The steps of the method disclosed in the present invention may be directly implemented as being executed by a hardware processor, or may be executed by a combination of hardware and software modules in the processor.

[0192] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. An active distribution line harmonic injection protection method based on control and protection coordination is characterized in that: include: Acquire a voltage time sequence change state of a distributed inverter-type new energy power grid-connected point, and generate an injection characteristic signal of the new energy power grid-connected point when the voltage time sequence change state meets a first preset requirement; combining the injection characteristic signal with a modulation signal controlled by an inverter; Extracting electric energy characteristic information on both sides of the new energy power supply grid connection point, obtaining the amplitude ratio of characteristic harmonic currents on both sides according to a preset analysis model, and determining the first fault location based on the amplitude ratio; Analyze the first device attribute of the new energy power grid connection point at the first fault location, compare the first device attribute with the second device attribute of other new energy power grid connection points, and determine the high-risk protection area of ​​the distribution line; Performing numerical analysis on the amplitude ratio to determine the first fault location includes: If the amplitude ratio is greater than 1, the first fault location is determined to be a fault within the line area, and auxiliary judgment processing is performed based on the phase angle difference between the harmonic current and the fundamental frequency current; If the amplitude is not greater than 1, the first fault location is judged to be a fault outside the line area or empty; If the amplitude ratio is greater than 1, the first fault position is judged to be a fault within the line area, and auxiliary judgment processing is performed based on the phase angle difference between the harmonic current and the fundamental frequency current, including: Obtaining a cosine value of a phase angle difference between a harmonic current and a fundamental frequency current of a line in the area, and obtaining a first numerical attribute of the cosine value, wherein the first numerical attribute includes a positive attribute or a negative attribute; Obtaining a cosine value of a phase angle difference between a harmonic current and a fundamental frequency current of an out-of-area line, and obtaining a second numerical attribute of the cosine value, wherein the second numerical attribute includes a positive attribute or a negative attribute; If the product of the first numerical attribute and the second numerical attribute is a negative number, it is determined to be an in-zone fault; If the product of the first numerical attribute and the second numerical attribute is a positive number, it is determined to be an out-of-zone fault; The analyzing the first device attribute of the new energy power grid connection point at the first fault location, comparing the first device attribute with the second device attribute of other new energy power grid connection points, and determining the high-risk protection area of ​​the distribution line includes: If the first fault location is an in-area fault, obtaining a first device attribute of a new energy power supply grid connection point in the area; Compare the first attribute information of the first device attribute with the second attribute information in the second device attribute of other new energy power grid connection points to obtain a device similarity coefficient; If the device similarity coefficient is greater than a first preset value, a first state of the device in the zone at the first fault location when the fault occurs is obtained, and a high-risk protection area of ​​the distribution line is determined based on the device similarity coefficient and the first state, wherein the high-risk protection area is an area within the zone, and the first state is an environmental state corresponding to the device in the zone; The first attribute information of the first device attribute and the second attribute information in the second device attribute of other new energy power supply grid connection points are compared to obtain the device similarity coefficient, including: The attribute information includes fixed information and dynamic information, wherein the fixed information includes at least line length information and power generation information, and the dynamic information includes at least temperature information and humidity information; Compare the first fixed information in the first attribute information with the second fixed information in the second attribute information to obtain a first similarity sub-coefficient; Compare the first dynamic information in the first attribute information with the second dynamic information in the second attribute information to obtain a second similarity sub-coefficient; Based on the first similarity sub-coefficient and the second similarity sub-coefficient, a fused device similarity coefficient is obtained. The device similarity coefficient is calculated by the following formula: ， in, is the equipment similarity coefficient, is the line length information in the first fixed information, is the line length information in the first fixed information, is the length coefficient value, is the power generation information in the first fixed information, is the power generation information in the second fixed information, is the power coefficient value, To fix the similarity weight, For the The first dynamic information of the dynamic dimension, For the The second dynamic information of the dynamic dimension, is the upper limit of the dynamic dimension, For the Similarity weights of dynamic dimensions, is the dynamic similarity weight.

2. The active distribution line harmonic injection protection method based on control and protection coordination according to claim 1 is characterized in that: The step of obtaining a voltage time sequence change state of a distributed inverter-type new energy power supply grid-connected point and generating an injection characteristic signal of the new energy power supply grid-connected point when the voltage time sequence change state meets a first preset requirement includes: Continuously acquiring the voltage time sequence change state of the distributed inverter-type new energy power supply grid connection point, and if it is determined that the voltage drop amplitude is less than a preset value, then determining that the voltage time sequence change state meets the first preset requirement; The rated power information of the new energy power grid connection point is obtained, and a corresponding injection characteristic signal is generated based on the rated power information and a preset calculation formula. The injection characteristic signal includes at least a signal amplitude and a signal frequency.

3. The active distribution line harmonic injection protection method based on control and protection coordination according to claim 2 is characterized in that: The extracting of electric energy characteristic information on both sides of the new energy power supply grid connection point, obtaining the amplitude ratio of characteristic harmonic currents on both sides according to a preset analysis model, and determining the first fault location based on the amplitude ratio include: Extracting the electric energy amplitudes on both sides of the new energy power supply grid connection point to obtain electric energy characteristic information, wherein the electric energy characteristic information includes inner electric energy information and outer electric energy information; Compare the harmonic current amplitudes in the inner power information and the outer power information, take the corresponding amount with the larger amplitude as the numerator and the corresponding amount with the smaller amplitude as the denominator, and calculate the amplitude ratio of the characteristic harmonic currents on both sides of the line; The amplitude ratio is numerically analyzed to determine the first fault location.

4. The active distribution line harmonic injection protection method based on control and protection coordination according to claim 1 is characterized in that: The high-risk protection area of ​​the distribution line is determined based on the device similarity coefficient and the first state, and the high-risk protection area is an area within the zone, including: If the power generation information in the first fixed information is greater than the power generation information in the second fixed information, the power generation value in the first state is adjusted downward based on the device similarity coefficient; If the power generation information in the first fixed information is less than the power generation information in the second fixed information, the power generation value in the first state is adjusted upward based on the device similarity coefficient, The power generation value in the adjusted first state is calculated by the following formula: ， in, is the power generation value in the first state after adjustment, is the power generation value in the first state before adjustment, is the normalized value.

5. The active distribution line harmonic injection protection method based on control and protection coordination according to claim 1 is characterized in that: The analyzing the first device attribute of the new energy power grid connection point at the first fault location, comparing the first device attribute with the second device attribute of other new energy power grid connection points, and determining the high-risk protection area of ​​the distribution line includes: If the first fault location is an out-of-area fault, obtaining a first device attribute of a new energy power grid connection point in the area and a first line attribute of a line where the new energy power grid connection point is located; Compare the first attribute information of the first device attribute with the second attribute information in the second device attribute of other new energy power grid connection points to obtain a device similarity coefficient; Compare the first line information of the first line attribute with the second line information in the second line attribute of other new energy power grid connection points to obtain a line similarity coefficient; The device similarity coefficient and the line similarity coefficient are merged to obtain a total similarity coefficient. If the total similarity coefficient is greater than a second preset value, the second states of the equipment within the zone and the equipment outside the zone at the first fault location when the fault occurs are obtained. Based on the device similarity coefficient and the second state, the high-risk protection area of ​​the distribution line is determined, and the high-risk protection area is the area outside the zone.

6. The active distribution line harmonic injection protection method based on control and protection coordination according to claim 5 is characterized in that: If the first fault location is an out-of-area fault, obtaining a first device attribute of a new energy power grid connection point in the area and a first line attribute of a line where the new energy power grid connection point is located includes: Taking the grid connection point of the new energy power source as the initial point, the preset distances on both sides of the line are extended to obtain the line where it is located; The grid-connected rated power of other coordinated new energy power grid-connected points in the line and the rated load of the load are obtained to obtain the first line attribute.

7. The active distribution line harmonic injection protection method based on control and protection coordination according to claim 6 is characterized in that: The first line information of the first line attribute and the second line information in the second line attribute of other new energy power supply grid connection points are compared to obtain the line similarity coefficient, including: Compare the first number of coordinated new energy power grid connection points and the first grid-connected rated power in the first line information with the second number of coordinated new energy power grid connection points and the second grid-connected rated power in the second line information to obtain a first coordination coefficient; Compare a first rated load of a first load in the first line information with a second rated load of a second load in the second line information to obtain a second coordination coefficient; Based on the first cooperation coefficient and the second cooperation coefficient, a line similarity coefficient is obtained. The line similarity coefficient is calculated by the following formula: ， in, is the line similarity coefficient, The first number of new energy power grid connection points, The second number of new energy power grid connection points, is the quantity coefficient weight, is the first grid-connected rated capacity, is the second grid-connected rated capacity, is the rated power coefficient value, is the first collaborative weight, is the first rated load of the first load, is the second rated load of the second load, is the rated load factor value, is the second collaborative weight.

8. The active distribution line harmonic injection protection method based on control and protection coordination according to claim 6 is characterized in that: The method of obtaining the second state of the equipment within the zone and the equipment outside the zone when the first fault location occurs, and determining the high-risk protection area of ​​the distribution line based on the equipment similarity coefficient and the second state, wherein the high-risk protection area is the area outside the zone, includes: obtaining the second state of the equipment within the zone and the equipment outside the zone when the first fault location occurs, wherein the second state includes at least the rated power within the zone, the rated power outside the zone, and the environmental state.

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