Distribution line overcurrent protection method, electronic equipment and computer storage medium

Abstract

The present application relates to the technical field of relay protection for power systems, and in particular to a method for overcurrent protection of distribution lines, an electronic device, and a computer storage medium. The method comprises: obtaining a plurality of line voltages and a plurality of line currents. According to a preset unit impedance value, a variable impedance is determined, and the variable impedance amplitude is positively correlated with the preset unit impedance value and the line length of the distribution line. According to the variable impedance, the first line current, and the first line voltage, an operating voltage is determined, and the first line current is any line current among the plurality of line currents that is greater than or equal to a preset overcurrent threshold. According to the operating voltage and the polarization voltage, a phase angle is determined. If the phase angle is within the preset angle range, a target action delay is determined, and the target action delay is negatively correlated with the variable impedance amplitude. The present application can determine the action delay corresponding to the line protection device, so that the action delay corresponding to each line protection device can be reliably distinguished, thereby increasing the number of line protection devices put into step-by-step coordination.

Description

Technical Field

[0001] The present application relates to the technical field of power system relay protection, and in particular to a distribution line overcurrent protection method, electronic equipment, and computer storage medium. Background Art

[0002] In power systems, stepped coordination is a strategy for overcurrent protection of distribution network lines (hereinafter referred to as distribution lines). Stepped coordination of action delays is a key method of this overcurrent protection step-by-step coordination. By gradually varying the action delays of individual line protection devices from the power source side to the load side, selective protection of distribution lines is achieved. The more line protection devices implemented in this stepped coordination method, the more accurately the fault point can be located, the smaller the isolated fault area, and the less impact the fault has on the power system.

[0003] To achieve step-by-step coordination, the time difference between the operating delays set on each line protection device must not be less than a certain time difference threshold. However, to ensure rapid fault clearing, the longest operating delay must also not exceed a certain operating delay threshold. Therefore, within a certain operating delay threshold, the number of operating delays that can be set to change in a step-by-step manner is limited, and the number of line protection devices actually operating in step-by-step coordination on distribution lines is relatively small. This results in lower fault location and isolation accuracy, a wider range of fault isolation, and a greater impact on the power system. Summary of the Invention

[0004] This application provides a method, device, electronic device, and computer-readable storage medium for overcurrent protection of distribution lines. These methods can determine the action delay corresponding to a line protection device, allowing the action delays corresponding to individual line protection devices to be reliably distinguished, thereby increasing the number of line protection devices deployed in a step-by-step coordination manner, thereby narrowing the scope of faults and reducing the impact of line faults on the power system.

[0005] In a first aspect, the present application provides a distribution line overcurrent protection method, which is applied to a line protection device, which is used to monitor the line status of a multi-phase distribution line. The method includes: obtaining multiple line voltages and multiple line currents, wherein the multiple line voltages and multiple line currents correspond one to one. Determining a variable impedance based on a preset unit impedance value, wherein the variable impedance amplitude is positively correlated with the preset unit impedance value, the variable impedance amplitude is the amplitude corresponding to the variable impedance, and the preset unit impedance value is positively correlated with the line length of the distribution line. Determining an operating voltage based on the variable impedance, a first line current, and a first line voltage, wherein the first line current is any line current among the multiple line currents that is greater than or equal to a preset overcurrent threshold, and the first line voltage is the line voltage among the multiple line voltages that corresponds to the first line current. Determining a phase angle based on the operating voltage and the polarization voltage. If the phase angle is within a preset angle range, determining a target action delay based on the variable impedance and a preset action delay, wherein the target action delay is negatively correlated with the variable impedance amplitude.

[0006] In some embodiments, determining the variable impedance based on a preset unit impedance value includes: obtaining a line impedance angle. The variable impedance is determined based on the line impedance angle, the preset unit impedance value, and a first time period. The variable impedance angle corresponding to the variable impedance is the same as the line impedance angle. The variable impedance amplitude is positively correlated with the first time period. The first time period starts at a first moment, which is when the line protection device detects a start signal. The first time period ends at the current moment.

[0007] In some embodiments, determining the variable impedance based on the line impedance angle, a preset unit impedance value, and a first time period includes: determining the quotient of the first time period divided by the sampling period as an amplitude coefficient; determining the product of the amplitude coefficient and the preset unit impedance value as the variable impedance amplitude; and determining the variable impedance based on the variable impedance amplitude and the line impedance angle.

[0008] In some embodiments, determining a target action delay based on a variable impedance and a preset action delay includes: obtaining a reference impedance; determining a ratio of a variable impedance amplitude to the reference impedance; determining an acceleration time of the line protection device based on the ratio and the preset action delay; and determining a target action delay based on the acceleration time and the preset action delay. If the difference between the preset action delay and the acceleration time is greater than or equal to the shortest action delay, determining the target action delay as the difference between the preset action delay and the acceleration time. If the difference between the preset action delay and the acceleration time is less than the shortest action delay, determining the target action delay as the shortest action delay.

[0009] In some embodiments, determining the operating voltage based on the variable impedance, the first line current, and the first line voltage includes determining the operating voltage as a difference between the first line voltage and the product of the variable impedance and the first line current.

[0010] In some embodiments, determining a phase angle based on an operating voltage and a polarization voltage includes: obtaining a rated voltage amplitude. Determining a minimum voltage amplitude based on the rated voltage amplitude, where the minimum voltage amplitude is proportional to the rated voltage amplitude. If multiple line voltages are less than or equal to the minimum voltage amplitude, determining a polarization voltage based on multiple reference line voltages, where the multiple reference line voltages are line voltages collected by the line protection device at a second moment, where the second moment is a moment k sampling periods before the first moment when the line protection device detects a start signal, where k is an integer greater than 0 and less than 5. If a second line voltage among the multiple line voltages is greater than the minimum voltage amplitude, determining the positive sequence voltage corresponding to the first line voltage as the polarization voltage. The angle of the ratio of the operating voltage to the polarization voltage is determined as the phase angle.

[0011] In some embodiments, multiple reference line voltages correspond one-to-one to multiple line voltages, and determining a polarization voltage based on the multiple reference line voltages includes: obtaining a sampling sequence number corresponding to a first line voltage, the sampling sequence number representing the number of times the line protection device has sampled the line voltage since a first moment; obtaining a number of cycle sampling points; determining a ratio of 360° to the number of cycle sampling points as a sampling angle step; determining a polarization voltage angle corresponding to the polarization voltage as the product of the sampling angle step and the sampling sequence number, and the sum of the first reference line voltage angle, where the first reference line voltage is one of the multiple reference line voltages corresponding to the first line voltage, and the first reference line voltage angle is the angle corresponding to the first reference line voltage; and determining the polarization voltage based on the polarization voltage angle.

[0012] In some embodiments, after determining a target action delay based on the variable impedance and a preset action delay, the method further includes: continuously acquiring multiple sets of second line currents within a second time period based on a preset sampling frequency, each set of second line currents including multiple second line currents, the multiple second line currents corresponding one-to-one to the multiple line currents, the start time of the second time period being the current time, and the time interval of the second time period being the target action delay. If the multiple target second line currents corresponding to the multiple sets of second line currents are all greater than or equal to a preset overcurrent threshold, then sending disconnect instructions to the multiple circuit breakers, the target second line current being the line current corresponding to the first line current among the multiple second line currents, the multiple circuit breakers corresponding one-to-one to the multi-phase distribution lines, the multiple circuit breakers being used to change the line state of the multi-phase distribution lines, and the disconnect instructions being used to instruct the circuit breakers to change the line state to a disconnected state.

[0013] In a second aspect, the present application provides a distribution line overcurrent protection device, which may be a line protection device. The distribution line overcurrent protection device is used to monitor the line status of a multi-phase distribution line. The device includes: an acquisition module and a determination module.

[0014] The acquisition module is used to acquire multiple line voltages and multiple line currents, where the multiple line voltages and the multiple line currents correspond to each other one by one.

[0015] The determination module is used to determine the variable impedance according to the preset unit impedance value, the variable impedance amplitude is positively correlated with the preset unit impedance value, the variable impedance amplitude is the amplitude corresponding to the variable impedance, and the preset unit impedance value is positively correlated with the line length of the distribution line.

[0016] The determination module is also used to determine the operating voltage based on the variable impedance, the first line current and the first line voltage, where the first line current is any line current among multiple line currents that is greater than or equal to a preset overcurrent threshold, and the first line voltage is the line voltage among multiple line voltages corresponding to the first line current.

[0017] The determination module is further configured to determine a phase angle based on the operating voltage and the polarization voltage. If the phase angle is within a preset angle range, a target action delay is determined based on the variable impedance and a preset action delay, where the target action delay is negatively correlated with the variable impedance amplitude.

[0018] In a third aspect, the present application provides an electronic device comprising a processor and a memory, wherein the processor is configured to execute a computer program stored in the memory to implement a method as described in any one of the first aspects above.

[0019] In a fourth aspect, the present application provides a computer-readable storage medium, which stores a computer program. When the computer program is executed by a processor, it implements the method as described in any one of the above-mentioned first aspects.

[0020] In the technical solution provided by this application, a line protection device can obtain multiple line voltages and currents in real time and determine a variable impedance based on a preset unit impedance value. The variable impedance amplitude is positively correlated with the preset unit impedance value, which is positively correlated with the length of the distribution line. Based on a preset overcurrent threshold, the operating voltage corresponding to the faulty distribution line is determined. A phase angle is then determined based on the operating voltage and polarization voltage. If the phase angle is within a preset angle range, a target action delay is determined based on the variable impedance and a preset action delay. The target action delay is negatively correlated with the variable impedance amplitude. This ensures that the target action delay corresponding to the line protection device closest to the fault point is minimized, allowing the action delays corresponding to each line protection device to be reliably distinguished. This increases the number of target action delays that can be set within the preset action delay range, thereby increasing the number of line protection devices activated for overcurrent protection. Once the line protection device closest to the fault point is activated, the fault range can be narrowed, reducing the impact of the line fault on the power system. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the embodiments or descriptions of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0022] Figure 1 This is a schematic diagram of the arrangement structure of a line protection device provided in an embodiment of the present application;

[0023] Figure 2 This is a schematic diagram of a circuit device for actual step-by-step coordination provided by an embodiment of the present application;

[0024] Figure 3 This is a flowchart of a fault diagnosis method provided by an embodiment of the present application;

[0025] Figure 4 This is a flow chart of a method for overcurrent protection of a power distribution line provided in an embodiment of the present application;

[0026] Figure 5 This is a schematic diagram of a distribution line overcurrent protection device provided in an embodiment of the present application;

[0027] Figure 6 This is a schematic diagram of an electronic device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0028] In the following description, specific details such as specific system structures and technologies are provided for illustration rather than limitation to facilitate a thorough understanding of the embodiments of the present application. However, it should be clear to those skilled in the art that the present application may be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to avoid obstructing the description of the present application with unnecessary details.

[0029] It should be understood that when used in the present specification and the appended claims, the term "comprising" indicates the presence of described features, integers, steps, operations, elements and / or components, but does not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or groups thereof.

[0030] It will also be understood that the term "and / or" used in this specification and the appended claims refers to and includes any and all possible combinations of one or more of the associated listed items.

[0031] As used in this specification and the appended claims, the term "if" can be interpreted as "when" or "upon" or "in response to determining" or "in response to detecting," depending on the context. Similarly, the phrase "if it is determined" or "if [described condition or event] is detected" can be interpreted as meaning "upon determination" or "in response to determining" or "upon detection of [described condition or event]" or "in response to detecting [described condition or event]," depending on the context.

[0032] In addition, in the description of the present application specification and the appended claims, the terms "first", "second", "third", etc. are only used to distinguish the descriptions and cannot be understood as indicating or implying relative importance.

[0033] References to "one embodiment" or "some embodiments" in this specification mean that a particular feature, structure, or characteristic described in conjunction with that embodiment is included in one or more embodiments of the present application. Thus, phrases such as "in one embodiment," "in some embodiments," "in other embodiments," and "in other embodiments" appearing in various places in this specification do not necessarily refer to the same embodiment, but rather mean "one or more but not all embodiments," unless otherwise specifically emphasized. The terms "including," "comprising," "having," and variations thereof all mean "including but not limited to," unless otherwise specifically emphasized.

[0034] Stepped coordination of overcurrent protection is a common protection strategy in power systems. It aims to achieve selective protection by setting the operation delay and overcurrent threshold of line protection devices in a hierarchical manner. This ensures that in the event of a fault, the line protection device closest to the fault point operates first, quickly isolating the fault and minimizing the scope of the power outage.

[0035] Stepped coordination of overcurrent protection includes step-by-step coordination of overcurrent thresholds (also known as current settings or overcurrent settings) and step-by-step coordination of action delays. The overcurrent thresholds are set on the line protection devices, and they change gradually from the power source side to the load side. The line protection devices closest to the source have the highest overcurrent thresholds, while those in the middle decrease in order, and the line protection devices closest to the end (load) have the lowest thresholds.

[0036] For example, Figure 1This is a schematic diagram of the arrangement architecture of line protection devices provided in an embodiment of the present application. The grid side is the power supply side, and line protection device 1, line protection device 2, line protection device 3, and so on are installed in order from the grid side to the load side. Line protection device 1 has the highest overcurrent threshold, while line protection device N has the lowest. The overcurrent thresholds for the line protection devices between line protection device 1 and line protection device N decrease in order.

[0037] Stepped delay coordination means that the delays set on the line protection devices gradually change from the power source to the load. The line protection device closest to the source has the longest delay, while those in the middle decrease in delay, and the line protection device closest to the end (load) has the shortest delay.

[0038] For example, see Figure 1 , the same overcurrent threshold is set for line protection devices 1 to line protection devices N, the action delay corresponding to line protection device 1 is the largest, the action delay corresponding to line protection device N is the smallest, and the action delays corresponding to the line protection devices between line protection device 1 and line protection device N decrease in sequence.

[0039] However, since distribution lines are usually short, when a fault occurs in the distribution line, the difference in fault current collected by each line protection device on the distribution line is usually small, making it difficult to achieve step-by-step coordination of overcurrent thresholds.

[0040] For example, see Figure 1 Line protection devices 1 through N divide the distribution line into multiple line segments: distribution line 1, distribution line 2, distribution line 3, and so on to distribution line N. Each line protection device corresponds to a specific line segment. When a fault occurs at point F1, ideally, line protection device 2 will clear the fault, minimizing the scope of the fault. However, due to the small differences in the fault currents detected by line protection devices 1 through N, it's difficult to determine which line protection device will clear the fault, making step-by-step coordination of overcurrent thresholds difficult.

[0041] Furthermore, to ensure rapid fault clearing, the operating delays set on line protection devices near the source (power source) must be limited to a minimum, and the differences between the operating delays set on each line protection device must be significant. This allows for reliable differentiation of the operating delays and the implementation of step-by-step coordination. Therefore, within a certain operating delay threshold range, the number of step-by-step operating delays that can be set is relatively small, and the number of line protection devices actually operating in step-by-step coordination on the line is also relatively small.

[0042] For example, for Figure 1Each line protection device in the circuit is configured so that the corresponding action delay of the line protection device presents an obvious step-by-step change. Figure 1 The actual step-by-step coordination of line protection devices is as follows: Figure 2 As shown, Figure 2 The line protection device M in Figure 1 The line protection device corresponding to the line protection device closest to the middle of the line, line protection device 1, line protection device M and line protection device N correspond to distribution line 1, distribution line M and distribution line N respectively.

[0043] When the line protection device investment is small, the distance of the distribution line corresponding to each line protection is longer. For example, continue to see Figure 2 If a fault occurs at point F2, the line protection device M will cut off the fault, but the fault range after isolation is large. The larger the fault range, the greater the impact on the power system.

[0044] In view of this, an embodiment of the present application provides a distribution line overcurrent protection method, which can determine the action delay corresponding to the line protection device, so that the action delay corresponding to each line protection device can be reliably distinguished, thereby increasing the number of line protection devices put into step-by-step coordination, so as to narrow the fault scope and reduce the impact of line faults on the power system.

[0045] The technical solutions of the embodiments of the present application are described below with reference to the examples in the accompanying drawings.

[0046] Figure 3 This is a flow chart of a fault identification method provided in an embodiment of the present application. The line protection device can perform fault identification by calculating the action delay. The method includes the following steps:

[0047] Step S301: Acquire multiple line voltages and multiple line currents, where the multiple line voltages and the multiple line currents correspond one to one.

[0048] In the technical solution provided in the embodiment of the present application, the line protection device can obtain multiple phase voltages and multiple phase currents corresponding to the multi-phase distribution line in real time, and calculate multiple line voltages and multiple line currents based on the multiple phase voltages and multiple phase currents.

[0049] In the embodiment of the present application, the multiple phase voltages and the multiple phase currents may be the phase voltages and phase currents corresponding to the three-phase distribution lines in a three-phase system.

[0050] For example, see Figure 1 , the line protection device can be Figure 1When the line protection device is line protection device 2, the multi-phase distribution line may be a three-phase line corresponding to distribution line 2, the multiple phase voltages may be three phase voltages corresponding to distribution line 2, and the multiple phase currents may be three phase currents corresponding to distribution line 2.

[0051] For example, the multi-phase distribution lines can be phase A, phase B, and phase C. The multiple phase voltages are: the voltage of phase A, the voltage of phase B, and the voltage of phase C, respectively expressed as: U A 、U B and U C The multiple phase currents can be: the current flowing through the A phase line, the current flowing through the B phase line, and the current flowing through the C phase line, respectively expressed as: I A , I B and I C .

[0052] In the embodiment of the present application, the line protection device can make a difference between any two voltages among a plurality of phase voltages to obtain a plurality of line voltages, and make a difference between any two currents among a plurality of phase currents to obtain a plurality of line currents.

[0053] For example, the multiple line voltages may be: the voltage between the A-phase line and the B-phase line, the voltage between the B-phase line and the C-phase line, and the voltage between the C-phase line and the A-phase line, respectively expressed as: U AB 、U BC and U CA .

[0054] Among them, U AB =U A -U B ;

[0055] U BC =U B -U C ;

[0056] U CA =U C -U A ;

[0057] The multiple line currents can be respectively: the difference between the current in the conductor corresponding to the A phase line and the current in the conductor corresponding to the B phase line, the difference between the current in the conductor corresponding to the B phase line and the current in the conductor corresponding to the C phase line, and the difference between the current in the conductor corresponding to the C phase line and the current in the conductor corresponding to the A phase line, respectively expressed as: I AB , I BC and I CA .

[0058] Among them, I AB =IA -I B ;

[0059] I BC =I B -I C ;

[0060] I CA =I C -I A .

[0061] Step S302: When the line protection device detects a start signal, the moment of detecting the start signal is recorded as a first moment, and a plurality of baseline line voltages are obtained. The plurality of baseline line voltages are the line voltages obtained by the line protection device at a second moment.

[0062] If the line protection device does not detect a start signal, it indicates that the distribution line in the power system is operating normally, and the line protection device does not need to perform fault diagnosis, thus saving computing power. If the line protection device detects a start signal, it indicates that there may be a fault in the distribution line in the power system, and the line protection device initiates fault diagnosis and executes the protection process.

[0063] During normal operation, the line protection device typically collects a line voltage angle that is close to the line voltage angle collected one or several sampling cycles prior. Furthermore, after a distribution line fault occurs (after the line protection device detects a start signal), the corresponding line voltage may change significantly. Therefore, the line protection device can use the line voltage angle collected k sampling cycles prior as the power supply potential angle. That is, the second moment is a moment k sampling cycles prior to the first moment. In this embodiment of the present application, k can be an integer greater than 0 and less than 5.

[0064] For example, when k is 2 and the sampling period is 20ms, the multiple reference line voltages can be the multiple reference line voltages collected by the line protection device 40ms before the first moment, which are recorded as U 3AB 、U 3BC and U 3CA .

[0065] Step S303: Determine the faulty phase distribution line according to a preset overcurrent threshold.

[0066] In the embodiment of the present application, the line protection device can continuously determine the faulty phase distribution line according to the sampling frequency of the line voltage and the line current after detecting the start signal.

[0067] For example, after the line protection device detects a start signal at time T1 (i.e., the first time), it can obtain multiple line currents at time T1 and determine the line corresponding to the line current greater than a preset overcurrent threshold as the faulty phase distribution line. It is understood that the faulty phase distribution line can be single-phase or multi-phase, and this application does not limit this.

[0068] For example, the preset overcurrent threshold is I set , the multiple line currents obtained by the line protection device at time T1 are I 1AB , I 1BC and I 1CA , if I 1AB >I set , I 1BC >I set And I 1CA <I set , the line protection device can determine that the faulty phase distribution lines are the AB phase line and the BC phase line. The line protection device then performs fault discrimination on the AB phase line and the BC phase line respectively. The embodiment of the present application uses the line protection device's discrimination process for one phase faulty phase distribution line as an example to illustrate. It should be understood that the line protection device's discrimination process for other phase faulty phase distribution lines has the same or similar discrimination principles as the fault discrimination process provided in the embodiment of the present application.

[0069] The line protection device obtains multiple line currents I and I at time T2 (a sampling time after the first time and adjacent to the first time) according to the preset sampling frequency. 2AB , I 2BC and I 2CA , if I 2AB >I set , I 2BC >I set And I 2CA <I set , the line protection device can determine that the AB phase line and the BC phase line are still the fault phase distribution lines at time T2.

[0070] Step S304: Determine the operating voltage corresponding to the fault phase distribution line.

[0071] At the first moment and after the first moment, the line protection device may calculate the operating voltage corresponding to the fault phase distribution line in real time based on the acquired multiple line voltages and multiple line currents. The method for the line protection device to calculate the operating voltage may be:

[0072] Step A1: Calculate the variable impedance.

[0073] In the embodiment of the present application, the variable impedance The calculation formula can be: ;

[0074] Here, n represents an amplitude coefficient, and the line protection device can determine the amplitude coefficient according to the time difference between the current moment and the first moment.

[0075] If the first time interval is a first period of time between the current moment and the first time interval, the line protection device determines the quotient of the first period of time divided by the sampling period as the amplitude coefficient. In other words, the amplitude coefficient represents the number of whole cycles between the current line voltage or current and the line voltage or current sampled at the first moment of time.

[0076] For example, if the sampling period is 20 ms and the first time period is 40 ms, n = 40 ms / 20 ms = 2, and the line protection device determines the amplitude coefficient n to be 2. If the time interval between the current line voltage or line current sampling time and the first moment is 70 ms, n = 70 ms / 20 ms = 3 ... 10 ms, and the line protection device determines n to be 3. If the current moment is the first moment and the first time period is 0, then n is 0.

[0077] Represents a preset unit impedance value, i.e., the impedance value corresponding to a distribution line. The line protection device can set the preset unit impedance value based on the length of the distribution line. The preset unit impedance value can be positively correlated with the length of the distribution line corresponding to the line protection device.

[0078] For example, see Figure 1 The preset unit impedance value may be the impedance value corresponding to 0.25 times the length of the distribution line corresponding to the line protection device. For example, if the line protection device is line protection device 2, then its corresponding distribution line is distribution line 2. If the line length corresponding to distribution line 2 is 4 km, then the line protection device may set the preset unit impedance value to the impedance value corresponding to each 1 km of distribution line. If the line protection device is line protection device 3, and the corresponding distribution line is distribution line 3. If the line length corresponding to distribution line 3 is 2 km, then the line protection device may set the preset unit impedance value to the impedance value corresponding to each 500 m of distribution line. The embodiments of the present application do not limit the specific method for setting the preset unit impedance value.

[0079] Indicates the amplitude corresponding to the variable impedance, that is, the variable impedance amplitude coefficient X.

[0080] It represents the line impedance angle, that is, the impedance angle corresponding to the distribution line, which is a known constant.

[0081] Indicates the angle corresponding to the variable impedance (variable impedance angle).

[0082] Step A2: Determine the operating voltage corresponding to the fault phase distribution line based on the variable impedance.

[0083] In the embodiment of the present application, the working voltage The calculation formula can be: ;

[0084] in, Indicates the line voltage corresponding to the fault phase distribution line, Indicates the line current corresponding to the fault phase distribution line, Indicates variable impedance.

[0085] For example, if the fault phase distribution line is the AB phase line, then Can be the line current I corresponding to the AB phase line AB , is the line voltage U corresponding to the AB phase line AB ,Right now .

[0086] Step S305: Determine the polarization voltage corresponding to the fault phase distribution line.

[0087] In an embodiment of the present application, a method for determining a polarization voltage by a line protection device may include the following steps:

[0088] Step B1: Perform low voltage determination based on multiple line voltages.

[0089] In this embodiment of the present application, the line protection device can determine whether multiple line voltages are all low voltage. If all of the multiple line voltages are low voltage, the line protection device determines the polarization voltage based on the multiple baseline line voltages. If any of the multiple line voltages is not low voltage, the line protection device directly calculates the polarization voltage based on the multiple line voltages.

[0090] The line protection device can determine a minimum voltage amplitude based on the rated voltage amplitude. The minimum voltage amplitude can be proportional to the rated voltage amplitude. For example, the minimum voltage amplitude can be 0.05 times the rated voltage amplitude. This application does not limit the specific value of the minimum voltage amplitude. The line protection device can also determine whether multiple line voltages are all less than the minimum voltage amplitude to determine whether the multiple line voltages are all low voltage.

[0091] Step B2: If the multiple line voltages are all less than the minimum voltage amplitude, then determine the polarization voltage based on the multiple reference line voltages.

[0092] If multiple line voltages are all less than the minimum voltage amplitude, the line protection device determines that the multiple line voltages are all low voltages. If multiple line voltages are all less than the minimum voltage amplitude, this indicates that the multiple line voltages are very low, close to zero, making it difficult for the line protection device to determine the voltage angles of the multiple line voltages. Therefore, the line protection device can determine the polarization voltage based on multiple baseline line voltages.

[0093] The method for the line protection device to determine the polarization voltage based on multiple reference line voltages may be:

[0094] Step B2-1: Calculate the polarization voltage angle.

[0095] Polarization voltage angle The calculation formula can be: ;

[0096] in, Indicates the angle of the reference line voltage corresponding to the fault phase distribution line, that is, the reference line voltage angle. For example, if the fault phase distribution line is the AB phase line, It means that among the multiple reference line voltages obtained by the line protection device at the second moment, the reference line voltage U corresponding to the AB phase line is 1AB The angle of for .

[0097] M represents the sampling sequence number of the baseline voltage corresponding to the faulty phase distribution line. The line protection device can record the sampling sequence number of each sampling operation, starting from the first moment. For example, the sampling sequence number of the first sampling operation can be recorded as 0, and the sampling sequence number of the next sampling operation after the first moment can be recorded as 1. For each subsequent sampling operation, the sampling sequence number is incremented by 1 to record the sampling sequence number corresponding to each sampling operation after the first moment. For example, if the current sampling operation is the 50th sampling operation performed by the line protection device after the first moment according to the sampling frequency, then M = 50.

[0098] Indicates the sampling angle step, which is the ratio of 360° to the number of sampling points in a cycle. It is understandable that if the line protection device samples according to the sampling frequency, the sampling angle will change 360° after one sampling cycle. If the line protection device samples S times in one sampling cycle, the sampling angle will change every time it is sampled. times, that is .

[0099] It is understandable that in In the process of normal operation of the line protection device, the line voltage angle collected is usually close to the line voltage angle collected one or several sampling cycles ago. Then it can represent the angle of the power supply potential corresponding to the first moment. It is used to represent the angle change of the line voltage in the first time period (the period from the first moment to the current moment). Therefore, It can represent the polarization voltage angle at the current moment.

[0100] Step B2-2: Calculate the polarization voltage according to the polarization voltage angle.

[0101] In the embodiment of the present application, if the multiple line voltages are all less than the minimum voltage amplitude, the amplitude corresponding to the polarization voltage can be set to a smaller constant. For example, the amplitude corresponding to the polarization voltage can be 1, that is, the polarization voltage Can be , Indicates the angle corresponding to the polarization voltage.

[0102] Step B3: If there is a line voltage greater than or equal to the minimum voltage amplitude among the multiple line voltages, calculate the polarization voltage based on the multiple line voltages.

[0103] The line protection device can determine the positive sequence voltage corresponding to the fault phase distribution line as the polarization voltage.

[0104] For example, if the fault phase distribution line is AB phase line, the polarization voltage The calculation formula can be:

[0105] ;

[0106] Among them, U AB Indicates the line voltage corresponding to the AB phase line obtained at the current moment, U CA It is used to indicate the line voltage corresponding to the CA phase line obtained at the current moment, U BC It represents the line voltage corresponding to the BC phase line obtained at the current moment, a represents the positive sequence rotation factor, .

[0107] Step S306: Determine the target action delay according to the operating voltage and the polarization voltage.

[0108] In the embodiment of the present application, after determining the operating voltage and the polarization voltage, the line protection device may determine a target action delay corresponding to the line protection device according to the operating voltage and the polarization voltage.

[0109] The method for determining the target action delay of a line protection device according to the operating voltage and the polarization voltage may include:

[0110] Step C1: Determine the phase angle according to the operating voltage and the polarization voltage.

[0111] Phase Angle The calculation formula can be: ;

[0112] in, Indicates the operating voltage, represents the polarization voltage, The angle that represents the ratio of the operating voltage to the polarization voltage, also known as the phase angle.

[0113] Step C2: If the phase angle is within the preset angle range, the acceleration time of the line protection device is determined according to the amplitude coefficient of the variable impedance.

[0114] In the embodiment of the present application, the preset angle range may be a preset negative angle range. For example, the preset angle range may be (125°, 325°), that is, if 125° < <325°, the line protection device determines the acceleration time of the line protection device according to the amplitude coefficient of the variable impedance.

[0115] In some embodiments, the preset angle range may also be (90°, 270°) or other preset angle ranges, which is not limited in this application.

[0116] Acceleration time The calculation formula can be: ;

[0117] in, Indicates the preset action delay. In the embodiment of the present application, the preset action delay corresponding to each line protection device on the power distribution line of the power system can be the same. For example, the preset action delay can be set to 500ms.

[0118] X represents the amplitude coefficient of the variable impedance, that is, the variable impedance The corresponding amplitude coefficient .

[0119] Z represents the reference impedance, which is a known constant. The line protection device can determine the reference impedance based on the empirical impedance value of the corresponding distribution line, for example, according to the impedance value of the length of the distribution line corresponding to the line protection device, which is not limited in this application.

[0120] Step C2: Determine the target action delay according to the acceleration time.

[0121] Target action delay The calculation formula can be: ; That is, the target action delay To preset action delay and acceleration time difference.

[0122] It is understandable that the closer the line protection device is to the fault point, the smaller the amplitude coefficient X of the variable impedance. middle, is a constant. The smaller X is, the The smaller; The smaller the The bigger; The larger the The larger it is, the smaller X is. The bigger. Because, , The larger the value, the longer the target action will be delayed. It should be understood that the closer the line protection device is to the fault point, the smaller the target action delay calculated by the embodiment of the present application.

[0123] In some embodiments, to ensure the effectiveness of fault removal, the target action delay cannot be too small. The line protection device can be set with a minimum action delay. If the difference between the preset action delay and the acceleration time is greater than or equal to the shortest action delay, the target action delay is determined to be the difference between the preset action delay and the acceleration time; if the difference between the preset action delay and the acceleration time is less than the shortest action delay, the target action delay is determined to be the shortest action delay.

[0124] Step S307: Determine the fault judgment result according to the target action delay.

[0125] In an embodiment of the present application, after the line protection device detects a start signal, it continuously acquires multiple sets of second-line currents within a second time period based on a preset sampling frequency. Each set of second-line currents includes multiple second-line currents, and the multiple second-line currents correspond one-to-one to the multiple line currents. The start time of the second time period is the current time, and the time interval of the second time period is the target action delay. If the multiple target second-line currents corresponding to the multiple sets of second-line currents are all greater than or equal to the preset overcurrent threshold, a disconnect instruction is sent to each of the multiple circuit breakers. The target second-line current is the line current among the multiple second-line currents that corresponds to the first line current. The multiple circuit breakers correspond one-to-one to the multi-phase distribution lines. The multiple circuit breakers are used to change the line state of the multi-phase distribution lines. The disconnect instruction is used to instruct the circuit breaker to change the line state to the disconnected state.

[0126] In the technical solutions provided by the embodiments of the present application, each line protection device in the power system is equipped with the same preset action delay, minimum action delay, and preset overcurrent threshold. For any of the multiple line protection devices, upon detecting a start signal, the line protection device can determine the faulty distribution line based on the preset overcurrent threshold. For any faulty distribution line, the line protection device can calculate the variable impedance, thereby determining the operating voltage based on the variable impedance, and the polarization voltage. Based on the operating voltage and polarization voltage, the target action delay corresponding to the line protection device is determined. The closer the line protection device is to the fault point, the shorter its corresponding target action delay. When the line current corresponding to the faulty distribution line remains greater than or equal to the preset overcurrent threshold within the target action delay, the line protection device can send disconnect commands to each of its corresponding multiple circuit breakers to disconnect the line. This ensures that the line protection action closest to the fault point is executed first to disconnect the fault, minimizing the scope of the fault and improving the reliability of power system operation.

[0127] Corresponding to the fault identification method provided in steps S301 to S307 above, the embodiment of the present application provides a distribution line overcurrent protection method, such as Figure 4 As shown, the following steps may be included:

[0128] Step S401: Acquire multiple line voltages and multiple line currents, where the multiple line voltages and the multiple line currents correspond one to one.

[0129] In an embodiment of the present application, the multiple line voltages and the multiple line currents may be three line voltages and three line currents collected by the line protection device in a three-phase system, namely, the line voltage and line current corresponding to the AB phase line, the line voltage and line current corresponding to the BC phase line, and the line voltage and line current corresponding to the CA phase line.

[0130] For specific acquisition methods, please refer to Figure 3 In the corresponding embodiment, the line protection device obtains descriptions corresponding to multiple line voltages and multiple line currents, which will not be elaborated in this application.

[0131] Step S402: determining a variable impedance according to a preset unit impedance value, wherein the variable impedance amplitude is positively correlated with the preset unit impedance value, the variable impedance amplitude is the amplitude corresponding to the variable impedance, and the preset unit impedance value is positively correlated with the line length of the distribution line.

[0132] The preset unit impedance value may be a known impedance value. The method for determining the variable impedance of the line protection device according to the preset unit impedance value may refer to Figure 3 In the corresponding embodiment, the line protection device determines the description corresponding to the variable impedance according to the preset unit impedance value, which is not elaborated in this application.

[0133] Step S403: Determine the operating voltage based on the variable impedance, the first line current and the first line voltage, where the first line current is any line current among the multiple line currents that is greater than or equal to the preset overcurrent threshold, and the first line voltage is the line voltage among the multiple line voltages corresponding to the first line current.

[0134] The line protection device can determine the difference between the first line voltage and the product of the variable impedance and the first line current as the operating voltage. The specific calculation method can be referred to Figure 3 In the corresponding embodiment, the line protection device determines the description of the operating voltage based on the variable impedance, the first line current and the first line voltage, which is not repeated here in this application.

[0135] Step S404: Determine the phase angle according to the operating voltage and the polarization voltage.

[0136] The phase angle can be the angle of the ratio of the working voltage to the polarization voltage. The specific calculation method of the phase angle can be referred to Figure 3 In the corresponding embodiment, the description of how the line protection device determines the phase angle is not repeated in this application.

[0137] Step S405: If the phase angle is within the preset angle range, a target action delay is determined according to the variable impedance and the preset action delay, where the target action delay is negatively correlated with the variable impedance amplitude.

[0138] The line protection device can realize overcurrent protection according to the target action delay and the preset overcurrent threshold. The specific calculation method of the target action delay can be referred to Figure 3 In the corresponding embodiment, the description of how the line protection device determines the target action delay is not repeated in this application.

[0139] In the technical solution provided by the embodiments of the present application, a line protection device can obtain multiple line voltages and currents in real time and determine a variable impedance based on a preset unit impedance value. The variable impedance amplitude is positively correlated with the preset unit impedance value, which is positively correlated with the length of the distribution line. Based on a preset overcurrent threshold, the operating voltage corresponding to the faulty distribution line is determined. A phase angle is then determined based on the operating voltage and polarization voltage. If the phase angle is within a preset angle range, the line protection device determines a target action delay based on the variable impedance and a preset action delay. The target action delay is negatively correlated with the variable impedance amplitude. This ensures that the target action delay corresponding to the line protection device closest to the fault point is minimized, allowing the action delays corresponding to each line protection device to be reliably distinguished. This increases the number of target action delays that can be set within the preset action delay range, thereby increasing the number of line protection devices activated for overcurrent protection. Once the line protection device closest to the fault point is activated, the fault range can be narrowed, reducing the impact of the line fault on the power system.

[0140] It should be understood that, provided there is no logical conflict, the above-mentioned embodiments can be combined with each other to meet actual application requirements. The specific embodiments or implementation plans obtained by these combinations still fall within the scope of protection of this application.

[0141] Corresponding to the distribution line overcurrent protection method in the above embodiment, the present embodiment provides a distribution line overcurrent protection device 50, which can be a line protection device. The distribution line overcurrent protection device 50 can be implemented as part or all of a computer device using software, hardware, or a combination of both, and is configured to execute the steps in the distribution line overcurrent protection method in the above embodiment.

[0142] Figure 5 A schematic structural diagram of a distribution line overcurrent protection device provided in an embodiment of the present application is shown. For ease of explanation, only the parts related to the embodiment of the present application are shown.

[0143] Reference Figure 5 The distribution line overcurrent protection device 50 includes an acquisition module 510 and a determination module 520 .

[0144] The acquisition module 510 is configured to acquire a plurality of line voltages and a plurality of line currents, where the plurality of line voltages and the plurality of line currents correspond one to one.

[0145] The determination module 520 is used to determine the variable impedance according to the preset unit impedance value, the variable impedance amplitude is positively correlated with the preset unit impedance value, the variable impedance amplitude is the amplitude corresponding to the variable impedance, and the preset unit impedance value is positively correlated with the line length of the distribution line.

[0146] The determination module 520 is also used to determine the operating voltage based on the variable impedance, the first line current and the first line voltage, where the first line current is any line current among multiple line currents that is greater than or equal to a preset overcurrent threshold, and the first line voltage is the line voltage among multiple line voltages corresponding to the first line current.

[0147] Determination module 520 is further configured to determine a phase angle based on the operating voltage and the polarization voltage. If the phase angle is within a preset angle range, a target action delay is determined based on the variable impedance and a preset action delay, where the target action delay is negatively correlated with the variable impedance amplitude.

[0148] In some embodiments, the determination module 520 is specifically configured to obtain a line impedance angle, determine a variable impedance based on the line impedance angle, a preset unit impedance value, and a first time period, wherein the variable impedance angle corresponding to the variable impedance is the same as the line impedance angle, and the variable impedance amplitude is positively correlated with the first time period. The first time period starts at a first moment, which is the moment when the line protection device detects a start signal, and ends at the current moment.

[0149] In some embodiments, the determination module 520 is specifically configured to: determine the quotient of the first time period divided by the sampling period as an amplitude coefficient; determine the product of the amplitude coefficient and a preset unit impedance value as a variable impedance amplitude; and determine the variable impedance based on the variable impedance amplitude and the line impedance angle.

[0150] In some embodiments, determination module 520 is specifically configured to: obtain a reference impedance; determine a ratio of a variable impedance amplitude to the reference impedance; determine an acceleration time of the line protection device based on the ratio and a preset action delay; and determine a target action delay based on the acceleration time and the preset action delay. If the difference between the preset action delay and the acceleration time is greater than or equal to the shortest action delay, determine the target action delay as the difference between the preset action delay and the acceleration time. If the difference between the preset action delay and the acceleration time is less than the shortest action delay, determine the target action delay as the shortest action delay.

[0151] In some embodiments, the determination module 520 is specifically configured to determine that the difference between the first line voltage and the product of the variable impedance and the first line current is the operating voltage.

[0152] In some embodiments, determination module 520 is specifically configured to: obtain a rated voltage amplitude. Based on the rated voltage amplitude, a minimum voltage amplitude is determined, where the minimum voltage amplitude is proportional to the rated voltage amplitude. If multiple line voltages are less than or equal to the minimum voltage amplitude, a polarization voltage is determined based on multiple reference line voltages, where the multiple reference line voltages are line voltages collected by the line protection device at a second moment, where the second moment is a moment k sampling periods before the first moment when the line protection device detects a start signal, where k is an integer greater than 0 and less than 5. If a second line voltage greater than the minimum voltage amplitude exists among the multiple line voltages, the positive sequence voltage corresponding to the first line voltage is determined to be the polarization voltage. The angle of the ratio of the operating voltage to the polarization voltage is determined to be the phase angle.

[0153] In some embodiments, determination module 520 is specifically configured to: obtain a sampling sequence number corresponding to the first line voltage, the sampling sequence number being used to indicate the number of times the line protection device has sampled the line voltage since the first moment; obtain the number of cycle sampling points; determine the ratio of 360° to the number of cycle sampling points as the sampling angle step; determine the product of the sampling angle step and the sum of the first baseline voltage angle as the polarization voltage angle corresponding to the polarization voltage, where the first baseline voltage is one of multiple baseline voltages corresponding to the first line voltage, and the first baseline voltage angle is the angle corresponding to the first baseline voltage; and determine the polarization voltage based on the polarization voltage angle.

[0154] In some embodiments, the determination module 520 is further configured to: continuously acquire multiple groups of second-line currents within a second time period based on a preset sampling frequency, each group of second-line currents including multiple second-line currents, the multiple second-line currents corresponding one-to-one to the multiple line currents, the start time of the second time period being the current time, and the time interval of the second time period being the target action delay. If the multiple target second-line currents corresponding to the multiple groups of second-line currents are all greater than or equal to a preset overcurrent threshold, then send disconnect instructions to the multiple circuit breakers, respectively, where the target second-line current is the line current corresponding to the first line current among the multiple second-line currents, the multiple circuit breakers corresponding one-to-one to the multi-phase distribution lines, the multiple circuit breakers are configured to change the line state of the multi-phase distribution lines, and the disconnect instructions are configured to instruct the circuit breakers to change the line state to the disconnected state.

[0155] It should be noted that the information interaction, execution process, etc. between the above-mentioned devices / units are based on the same concept as the method embodiment of this application. Their specific functions and technical effects can be found in the method embodiment section and will not be repeated here.

[0156] It should be understood that the size of the serial numbers of the steps in the above embodiments 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 this application.

[0157] Based on the same inventive concept, an embodiment of the present application also provides an electronic device.

[0158] Figure 6 Schematic diagram of the structure of the electronic device provided in the embodiment of the present application. Figure 6 As shown, the electronic device 60 of this embodiment includes: at least one processor 610 ( Figure 6 Only one is shown), a memory 620, and a communication module 640. The memory 620 stores a computer program 630 that may be run on the processor 610. When the processor 610 executes the computer program 630, the steps in the above-mentioned distribution line overcurrent protection method embodiment are implemented, such as Figure 3 Alternatively, when the processor 610 executes the computer program 630, the functions of the modules / units in the above-mentioned device embodiments are realized, for example, Figure 5 The functions of modules 510 to 520 are shown, and the communication module 640 can be a separate communication unit for communicating with an external server or terminal device.

[0159] The electronic device 60 may include, but is not limited to: a processor 610 and a memory 620. Those skilled in the art will appreciate that Figure 6It is only an example of the electronic device 60 and does not constitute a limitation of the electronic device 60. It may include more or fewer components than shown in the figure, or a combination of certain components, or different components. For example, the electronic device 60 may also include an input sending device, a network access device, a bus, etc.

[0160] The processor 610 may be a central processing unit (CPU), other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA), other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor may be a microprocessor or any conventional processor.

[0161] In some embodiments, the memory 620 may be an internal storage unit of the electronic device 60, such as a hard drive or memory of the electronic device 60. The memory 620 may also be an external storage device of the electronic device 60, such as a plug-in hard drive, a Smart Media Card (SMC), a Secure Digital (SD) card, a flash memory card, etc. equipped on the electronic device 60. The memory 620 may also include both an internal storage unit of the electronic device 60 and an external storage device. The memory 620 is used to store an operating system, application programs, a boot loader, data, and other programs, such as the program code of the computer program 630. The memory 620 may also be used to temporarily store data that has been sent or is about to be sent.

[0162] In addition, those skilled in the art can clearly understand that for the convenience and simplicity of description, only the division of the above-mentioned functional units and modules is used as an example. In actual applications, the above-mentioned functions can be distributed and completed by different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units in the various embodiments of the present application can be integrated into a processing unit, or each unit can exist physically alone, or two or more units can be integrated into one unit. The above-mentioned integrated units can be implemented in the form of hardware or in the form of software functional units.

[0163] An embodiment of the present application provides a computer-readable storage medium, which stores a computer program. When the computer program runs on an electronic device, the electronic device executes the steps in the above-mentioned method embodiments.

[0164] An embodiment of the present application provides a chip, which includes a processor and a memory. The memory stores a computer program, and when the computer program is executed by the processor, the steps in the above-mentioned method embodiments are implemented.

[0165] An embodiment of the present application provides a computer program product. When the computer program product is run on an electronic device, the electronic device executes the steps in the above-mentioned various method embodiments.

[0166] It should be understood that the processor mentioned in the embodiments of the present application may be a central processing unit (CPU), or may also be other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field programmable gate arrays (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or any conventional processor, etc.

[0167] It should also be understood that the memory mentioned in the embodiments of the present application may be a volatile memory or a non-volatile memory, or may include both volatile and non-volatile memories. Among them, the non-volatile memory may be a read-only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), or a flash memory. The volatile memory may be a random access memory (RAM), which is used as an external cache. By way of example and not limitation, many forms of RAM are available, such as static random access memory (SRAM), dynamic random access memory (DRAM), synchronous dynamic random access memory (SDRAM), double data rate synchronous dynamic random access memory (DDR SDRAM), enhanced synchronous dynamic random access memory (ESDRAM), synchronous link dynamic random access memory (SLDRAM), and direct RAMbus RAM (DR RAM).

[0168] Those skilled in the art can clearly understand that, for the convenience and brevity of description, only the division of the above-mentioned functional units and modules is used as an example for illustration. In actual applications, the above-mentioned functions can be distributed and completed by different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiment can be integrated into one processing unit, or each unit can exist physically alone, or two or more units can be integrated into one unit. The above-mentioned integrated unit can be implemented in the form of hardware or in the form of software functional units. In addition, the specific names of the functional units and modules are only for the convenience of distinguishing each other, and are not used to limit the scope of protection of this application. The specific working process of the units and modules in the above-mentioned system can refer to the corresponding process in the aforementioned method embodiment, and will not be repeated here.

[0169] In the above embodiments, the description of each embodiment has its own focus. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant description of other embodiments.

[0170] Those skilled in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0171] In the embodiments provided in this application, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the system embodiments described above are merely schematic. For example, the division of the modules or units is merely a logical function division. In actual implementation, there may be other division methods, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be an indirect coupling or communication connection through some interfaces, devices or units, which can be electrical, mechanical or other forms.

[0172] The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of these units may be selected to achieve the purpose of this embodiment according to actual needs.

[0173] In addition, the functional units in the various embodiments of the present application may be integrated into a single processing unit, or each unit may exist physically separately, or two or more units may be integrated into a single unit. The aforementioned integrated units may be implemented in the form of hardware or software functional units.

[0174] If the integrated unit is implemented as a software functional unit and sold or used as a standalone product, it can be stored in a computer-readable storage medium. Based on this understanding, the present application implements all or part of the process steps in the above-mentioned method embodiments by instructing the relevant hardware through a computer program. The computer program can be stored in a computer-readable storage medium. When executed by a processor, the computer program can implement the steps of each of the above-mentioned method embodiments. The computer program includes computer program code, which can be in source code form, object code form, executable file, or some intermediate form. The computer-readable medium can include at least: any entity or device capable of carrying computer program code to a large-screen device, recording medium, computer memory, read-only memory (ROM), random access memory (RAM), electric carrier signals, telecommunication signals, and software distribution media. Examples include USB flash drives, removable hard drives, magnetic disks, or optical disks. In some jurisdictions, based on legislation and patent practice, computer-readable media cannot be electric carrier signals or telecommunication signals.

[0175] Finally, it should be noted that the above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any changes or substitutions within the technical scope disclosed in this application should be included in the scope of protection of this application. Therefore, the scope of protection of this application should be based on the scope of protection of the claims.

Claims

1. A method for overcurrent protection of a distribution line, characterized in that: Applied to a line protection device for monitoring the line status of a multi-phase distribution line, the method comprises: Acquire a plurality of line voltages and a plurality of line currents, wherein the plurality of line voltages and the plurality of line currents correspond one to one; Determine a variable impedance according to a preset unit impedance value, wherein the variable impedance amplitude is positively correlated with the preset unit impedance value, the variable impedance amplitude is an amplitude corresponding to the variable impedance, and the preset unit impedance value is positively correlated with the line length of the power distribution line; determining an operating voltage based on the variable impedance, a first line current, and a first line voltage, wherein the first line current is any line current among the multiple line currents that is greater than or equal to a preset overcurrent threshold, and the first line voltage is a line voltage among the multiple line voltages that corresponds to the first line current; Determining a phase angle according to the operating voltage and the polarization voltage; If the phase comparison angle is within a preset angle range, a target action delay is determined according to the variable impedance and a preset action delay, and the target action delay is negatively correlated with the variable impedance amplitude.

2. The method for overcurrent protection of a power distribution line according to claim 1, characterized in that: The step of determining the variable impedance according to the preset unit impedance value includes: Get line impedance angle; The variable impedance is determined based on the line impedance angle, the preset unit impedance value, and the first time period. The variable impedance angle corresponding to the variable impedance is the same as the line impedance angle. The variable impedance amplitude is positively correlated with the first time period. The start time of the first time period is the first time, the first time is the time when the line protection device detects the start signal, and the end time of the first time period is the current time.

3. The method for overcurrent protection of a power distribution line according to claim 2, characterized in that: The determining the variable impedance according to the line impedance angle, the preset unit impedance value, and the first time period includes: Determine the quotient of the first time period divided by the sampling period as the amplitude coefficient; Determine the product of the amplitude coefficient and the preset unit impedance value as the variable impedance amplitude; The variable impedance is determined according to the variable impedance amplitude and the line impedance angle.

4. The method for overcurrent protection of a distribution line according to claim 2, wherein: Determining a target action delay according to the variable impedance and the preset action delay includes: Obtaining the reference impedance; determining a ratio of the variable impedance amplitude to the reference impedance; determining an acceleration time of the line protection device according to the ratio and the preset action delay; Determining the target action delay according to the acceleration time and the preset action delay; If the difference between the preset action delay and the acceleration time is greater than or equal to the shortest action delay, then determining the target action delay as the difference between the preset action delay and the acceleration time; If the difference between the preset action delay and the acceleration time is smaller than the shortest action delay, the target action delay is determined to be the shortest action delay.

5. The method for overcurrent protection of a distribution line according to claim 1, characterized in that: The determining of the operating voltage according to the variable impedance, the first line current, and the first line voltage includes: The difference between the first line voltage and the product of the variable impedance and the first line current is determined to be the operating voltage.

6. The method for overcurrent protection of a distribution line according to claim 1, characterized in that: The determining of the phase angle according to the operating voltage and the polarization voltage includes: Get the rated voltage amplitude; Determining a minimum voltage amplitude according to the rated voltage amplitude, wherein the minimum voltage amplitude is proportional to the rated voltage amplitude; If the multiple line voltages are all less than or equal to the minimum voltage amplitude, determining the polarization voltage based on multiple reference line voltages, where the multiple reference line voltages are line voltages collected by the line protection device at a second moment, where the second moment is a moment before the first moment when the line protection device detects a start signal and is separated from the first moment by k sampling periods, where k is an integer greater than 0 and less than 5; If there is a second line voltage greater than the minimum voltage amplitude among the multiple line voltages, determining the positive sequence voltage corresponding to the first line voltage as the polarization voltage; The angle of the ratio of the operating voltage to the polarization voltage is determined as the phase angle.

7. The method for overcurrent protection of a distribution line according to claim 6, characterized in that: The multiple reference line voltages correspond one-to-one to the multiple line voltages, and determining the polarization voltage according to the multiple reference line voltages includes: Obtaining a sampling sequence number corresponding to the first line voltage, where the sampling sequence number is used to represent the number of times the line protection device samples the line voltage after the first moment; Get the number of cycle sampling points; Determine the ratio of 360° to the number of cycle sampling points as the sampling angle step; Determine the sum of the product of the sampling angle step and the sampling sequence number and the first reference line voltage angle as the polarization voltage angle corresponding to the polarization voltage, where the first reference line voltage is one of the multiple reference line voltages corresponding to the first line voltage, and the first reference line voltage angle is the angle corresponding to the first reference line voltage; The polarization voltage is determined according to the polarization voltage angle.

8. The method for overcurrent protection of a distribution line according to any one of claims 1 to 7, characterized in that: After determining the target action delay according to the variable impedance and the preset action delay, the method further includes: Based on a preset sampling frequency, continuously acquiring multiple groups of second line currents within a second time period, each group of second line currents including multiple second line currents, the multiple second line currents corresponding one-to-one to the multiple line currents, the start time of the second time period being the current time, and the time interval of the second time period being the target action delay; If multiple target second-line currents corresponding to multiple groups of second-line currents are all greater than or equal to the preset overcurrent threshold, disconnection instructions are sent to multiple circuit breakers respectively, where the target second-line current is the line current corresponding to the first line current among the multiple second-line currents, and the multiple circuit breakers correspond one-to-one to the multi-phase distribution lines. The multiple circuit breakers are used to change the line status of the multi-phase distribution lines, and the disconnection instructions are used to instruct the circuit breakers to change the line status to a disconnected state.

9. An electronic device, characterized in that: The invention comprises a processor and a memory, wherein the processor is used to execute a computer program stored in the memory to implement the distribution line overcurrent protection method as described in any one of claims 1 to 8.

10. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the method for overcurrent protection of a power distribution line as described in any one of claims 1 to 8 is implemented.

Images