Power distribution line distance protection method, electronic device and computer storage medium

Abstract

The application relates to the technical field of power system relay protection, in particular to a power distribution line distance protection method, an electronic device and a computer storage medium. The method comprises the following steps: acquiring a first measurement impedance corresponding to a fault phase, a preset unit inductance value and a preset step difference time. According to the preset unit inductance value, the preset step difference time and a first time interval, a target impedance rate is determined, the target impedance rate is positively correlated with the preset unit inductance value, and the target impedance rate is negatively correlated with the preset step difference time. According to the target impedance rate, a target inductance value and a target impedance value are determined. If the absolute value of the real part impedance of the first measurement impedance is less than the target impedance value, and the absolute value of the imaginary part inductance of the first measurement impedance is less than the target inductance value, the circuit breaker is instructed to change the line state to a disconnected state. The application can make the line protection device closest to the fault point act when a fault occurs in the power distribution line, and realize the minimization of fault area isolation.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of power system relay protection, and particularly relates to a power distribution line distance protection method, an electronic device and a computer storage medium. BACKGROUND

[0002] In a power system, distance protection is a widely used backup protection mode in high-voltage power grids of the power system. A line protection device can determine the distance between the line protection device and a fault point by calculating the difference between a measured impedance and a preset impedance when a fault occurs.

[0003] However, the preset impedance needs to be set based on accurate line parameter measurement. Since the existing power distribution lines are of various types and have a large number of lines, it is difficult to accurately measure the line parameters of each line between multiple line protection devices, and the distance protection mode of the power distribution line has low realizability.

[0004] In addition, when the lengths of the upper and lower lines are greatly different, the distance protection of the adjacent upper and lower line protection devices can easily lose selectivity, which can easily cause the line protection device to overstep and misoperate or refuse to operate when a line fault occurs. The distance protection mode of the power distribution line is difficult to implement in the application scenario where the lengths of the upper and lower lines are greatly different. SUMMARY

[0005] The present application provides a power distribution line distance protection method, an electronic device and a computer readable storage medium. When a fault occurs in a power distribution line, the line protection device closest to the fault point is enabled to act, without the need for accurate measurement of the line parameters of the protection line and without being affected by the length of the line, thereby improving the reliability of the line protection device action, minimizing the isolation of the fault area, and improving the reliability of the operation of the power distribution line.

[0006] In a first aspect, the present application provides a power distribution line distance protection method applied to a first line protection device for monitoring the line state of a first line section. The method comprises: obtaining a first measured impedance corresponding to a fault phase, and obtaining a preset unit reactance value and a preset step difference time. A target impedance rate is determined according to the preset unit reactance value, the preset step difference time and a first time interval. The target impedance rate is positively correlated with the preset unit reactance value, and the target impedance rate is negatively correlated with the preset step difference time. The starting time of the first time interval is the fault time, and the ending time of the first time interval is the current time. A target reactance value and a target impedance value are determined according to the target impedance rate. The target reactance value and the target impedance value are both positively correlated with the target impedance rate. If the absolute value of the real part impedance of the first measured impedance is less than the target impedance value, and the absolute value of the imaginary part reactance of the first measured impedance is less than the target reactance value, a disconnecting instruction is sent to a circuit breaker. The disconnecting instruction is used to instruct the circuit breaker to change the line state to a disconnected state.

[0007] In some embodiments, before the step of sending the opening instruction to the circuit breaker, the method further comprises: based on a preset sampling frequency, continuously obtaining a plurality of second measurement impedances corresponding to the fault phase within a preset time period, the preset time period being a time period after the current time and spaced from the current time by a second time interval.

[0008] In some embodiments, the step of sending the opening instruction to the circuit breaker comprises: if the absolute values of the real part impedances of the plurality of second measurement impedances are all less than the target impedance value, and the absolute values of the imaginary part reactances of the plurality of second measurement impedances are all less than the target reactance value, then sending the opening instruction to the circuit breaker.

[0009] In some embodiments, the step of obtaining the first measurement impedance corresponding to the fault phase comprises: obtaining a plurality of first line currents at a first time, the first time being any time before the first line protection device starts the distance protection process. If there is a line current greater than or equal to a preset overcurrent setting value in the plurality of first line currents, then recording the first time as the fault time, and determining the phase corresponding to the line current with the largest current amplitude in the plurality of first line currents as the fault phase. Obtaining a second line voltage and a second line current corresponding to the fault phase at a second time. Determining the ratio of the second line voltage to the second line current as the first measurement impedance.

[0010] In some embodiments, the line length corresponding to the first line section is a first line length, the line protection device adjacent to the first line protection device is a second line protection device, the second line protection device is configured to monitor the line state of a second line section, the line length corresponding to the second line section is a second line length. The target impedance rate is determined according to a preset unit reactance value, a preset differential time and a first time interval, comprising: if the first time interval is less than or equal to the preset differential time, then determining the target impedance rate as a first ratio value of the product of the preset unit reactance value and the first line length to the preset differential time. If the first time interval is greater than the preset differential time and less than or equal to twice the preset differential time, then determining the target impedance rate as a second ratio value of the product of the preset unit reactance value and the second line length to the preset differential time. If the first time interval is greater than twice the preset differential time, then determining the target impedance rate as the smaller one of the first ratio value and the second ratio value.

[0011] In some embodiments, determining a target inductive reactance value and a target impedance value based on a target impedance rate includes: if the first time interval is less than or equal to a preset step difference time, determining the target inductive reactance value as the product of the target impedance rate and the first time interval. If the first time interval is greater than the preset step difference time and less than or equal to twice the preset step difference time, determining the target inductive reactance value as the sum of a first additive term and a second additive term, wherein the first additive term is the product of a preset unit inductive reactance value and the first line length, and the second additive term is the product of the difference between the first time interval and the preset step difference time and the target impedance rate. If the first time interval is greater than twice the preset step difference time, determining the target inductive reactance value as the sum of a third additive term and a fourth additive term, wherein the third additive term is the product of the sum of the first line length and the second line length and the preset unit inductive reactance value, and the fourth additive term is the product of the difference between the first time interval and twice the preset step difference time and the target impedance rate. The target impedance value is determined based on the target impedance rate and a preset ratio coefficient, wherein the target impedance value is positively correlated with both the target inductive reactance value and the preset ratio coefficient.

[0012] In some embodiments, if the second line protection device does not exist, the value of the first line length is assigned to the second line length.

[0013] In some embodiments, the target impedance value is the product of the target inductive reactance value and a preset ratio coefficient.

[0014] In a second aspect, the present application provides a distribution line distance protection device, which may be a first line protection device, configured to monitor a line status of a first line segment, the device comprising: an acquisition module and a processing module;

[0015] The acquisition module is used to acquire the first measurement impedance corresponding to each fault phase, and to acquire a preset unit inductive reactance value and a preset step time.

[0016] The processing module is used to determine the target impedance rate based on the preset unit inductive reactance value, the preset step difference time and the first time interval, wherein the target impedance rate is positively correlated with the preset unit inductive reactance value and negatively correlated with the preset step difference time. The starting time of the first time interval is the fault time, and the ending time of the first time interval is the current time.

[0017] The processing module is further configured to determine a target inductive reactance value and a target impedance value based on the target impedance rate, wherein the target inductive reactance value and the target impedance value are both positively correlated with the target impedance rate. If the absolute value of the real impedance of the first measured impedance is less than the target impedance value, and the absolute value of the imaginary inductive reactance of the first measured impedance is less than the target inductive reactance value, a disconnect instruction is sent to the circuit breaker, wherein the disconnect instruction is configured to instruct the circuit breaker to change the line state to the disconnected state.

[0018] In a third aspect, the present application provides a chip, which is configured to execute the method in any one of the first aspect.

[0019] In a fourth aspect, the present application provides an electronic device, which comprises a processor and a memory, and the processor is configured to execute a computer program stored in the memory to implement the method in any one of the first aspect.

[0020] The electronic device comprises the chip in the third aspect.

[0021] In a fifth aspect, the present application provides a computer readable storage medium, which stores a computer program, and the computer program is configured to be executed by a processor to implement the method in any one of the first aspect.

[0022] In a sixth aspect, the present application provides a computer program product, which stores a computer program, and the computer program is configured to be executed by a processor to implement the method in any one of the first aspect.

[0023] In the technical solution provided in the present application, after the first line protection device obtains the first measurement impedance corresponding to the fault phase, and the preset unit inductance value and the preset differential time, the target impedance rate is determined according to the preset unit inductance value, the preset differential time and the first time interval, the target impedance rate is positively correlated with the preset unit inductance value, the target impedance rate is negatively correlated with the preset differential time, the starting time of the first time interval is the fault time, and the ending time of the first time interval is the current time. Then, the target inductance value and the target impedance value are determined according to the target impedance rate, and the target inductance value and the target impedance value are positively correlated with the target impedance rate. If the absolute value of the real part impedance of the first measurement impedance is less than the target impedance value, and the absolute value of the imaginary part inductance of the first measurement impedance is less than the target inductance value, a disconnection instruction is sent to the circuit breaker, and the disconnection instruction is used to instruct the circuit breaker to change the line state to a disconnected state. The technical solution provided in the present application can determine the specific area where the fault point is located when the distribution line fails, so that the line protection device closest to the fault point acts, the line parameters of the protection line do not need to be accurately measured, and the line length does not affect the action reliability of the line protection device, the reliability of the distribution line operation can be improved, and the fault area is minimized. BRIEF DESCRIPTION OF DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the embodiments or prior art description will be briefly introduced as follows. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0025] Figure 1 is a system architecture schematic diagram provided by an embodiment of the present application;

[0026] Figure 2 is a distance protection starting flow schematic diagram provided by an embodiment of the present application;

[0027] Figure 3 is a distance protection flow schematic diagram of a power distribution line distance protection method provided by an embodiment of the present application;

[0028] Figure 4 is a protection action area schematic diagram provided by an embodiment of the present application;

[0029] Figure 5 is a power distribution line distance protection device schematic diagram provided by an embodiment of the present application;

[0030] Figure 6 is an electronic device schematic diagram provided by an embodiment of the present application. DETAILED DESCRIPTION

[0031] In the following description, for the purposes of explanation and not limitation, specific details are set forth, such as particular system architectures, techniques, etc. in order to provide a thorough understanding of the embodiments of the present application. However, it will be apparent to those skilled in the art that the present application can be practiced in other embodiments that depart from these specific details. In other instances, detailed descriptions of well-known systems, devices, circuits, and methods are omitted so as not to obscure the description of the present application with unnecessary detail.

[0032] It is to be understood that the terminology "includes", "has", "holds", "contains" and / or "comprising", when used in this specification and in the following claims, indicates the presence of the 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.

[0033] It is also to be understood that the terminology "and / or" when used in this specification and in the following claims, refers to at least one of the items, or any combination of one or more of the items, associated with the "and / or" term.

[0034] As used in this specification and in the claims, the term "if" can be interpreted as meaning "when", or "once", or "in response to a determination", or "in response to detecting", as appropriate, depending on the context. Similarly, the phrase "if determined", or "if detected [the described condition or event]" can be interpreted as meaning "once determined", or "in response to a determination", or "once detected [the described condition or event]", or "in response to detecting [the described condition or event]", as appropriate, depending on the context.

[0035] 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.

[0036] 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.

[0037] Stepped overcurrent protection is a key method for achieving selective protection in distribution networks. By combining hierarchically set operating times and current settings, it ensures that only the protection closest to the fault point activates when a fault occurs, preventing over-tripping. It includes both time and current steps.

[0038] Time Ladder: The operating time increases gradually from the load side to the power side. Specifically, the line protection device closest to the load has the shortest operating delay, the line protection device closest to the power source has the longest operating delay, and the operating delays on the line protection devices in between increase in sequence.

[0039] For example, the operating time set on the line protection device from the load side to the power side is an arithmetic progression between 0.1s and 0.5s.

[0040] Current ladder: The current setting on the upper-level line protection device must be greater than that on the lower-level protection devices. This means that the current setting decreases step by step from the power source to the load. Specifically, the line protection device closest to the power source has the highest current setting, the line protection device closest to the load has the lowest overcurrent threshold, and the action delays on the intermediate line protection devices decrease in descending order.

[0041] For example, the current setting value set on the upper-level line protection device may be 1.2 to 1.5 times the current setting value set on the adjacent lower-level protection device.

[0042] For example, Figure 1 A schematic diagram of a system architecture provided in an embodiment of the present application. Figure 1As shown, the power grid side is the power supply side, and the line protection device 1, the line protection device 2 and the line protection device 3 are installed in turn from the power grid side to the load side. The line protection device 1 is the adjacent upper line protection device of the line protection device 2, and the line protection device 2 is the adjacent upper line protection device of the line protection device 3. The current setting corresponding to the line protection device 1 is the largest, and is 1.2 times of the current setting corresponding to the line protection device 2, and the current setting corresponding to the line protection device 2 is 1.2 times of the current setting corresponding to the line protection device 3.

[0043] The line protection device can realize the current step cooperation of overcurrent protection through the collected fault current. However, since the distribution line is usually short, when faults occur at different positions of the distribution line, the difference of the fault current flowing through the distribution line is usually small, which makes it difficult to realize the current step cooperation, and the line protection device cannot accurately isolate the fault area.

[0044] Distance protection is a widely used backup protection method for high-voltage power grids in power systems. The line protection device can determine the distance between the line protection device and the fault point by calculating the difference between the measured impedance and the preset impedance when a fault occurs.

[0045] However, the setting of the preset impedance requires accurate line parameter measurement, and since the existing distribution lines are of various types and have a large number of lines, it is difficult to accurately measure the line parameters of each line between multiple line protection devices, and the distance protection method of the distribution line has low realizability.

[0046] In addition, when the lengths of the upper and lower lines are greatly different, the distance protection of the adjacent upper and lower line protection devices can easily lose selectivity, which can easily cause the line protection device to overstep and misoperate or refuse to operate when a line fault occurs. The distance protection method of the distribution line is difficult to implement in the application scenario where the lengths of the upper and lower lines are greatly different.

[0047] Therefore, the embodiments of the present application provide a distance protection method for a distribution line, which can determine the specific area where the fault point is located when a fault occurs in the distribution line, so that the line protection device closest to the fault point operates. The line protection device does not need to accurately measure the line parameters of the protection line, and is not affected by the length of the line, which can improve the reliability of the operation of the line protection device, realize the minimization of the isolation of the fault area, and improve the reliability of the operation of the distribution line.

[0048] The technical solutions of the embodiments of the present application will be described below with reference to the examples in the drawings.

[0049] Figure 2 A distance protection starting process diagram is provided for the embodiments of the present application. As shown in the figure, Figure 1 Before starting the distance protection method for the distribution line, the line protection device can also perform the following steps:

[0050] Step S201: Obtain a plurality of first phase currents corresponding to the multi-phase power distribution line at a first time, the plurality of first phase currents correspond to the multi-phase power distribution line one by one, and the first time is any time before the first line protection device starts the distance protection process.

[0051] Before starting the power distribution line distance protection method, the line protection device can obtain a plurality of phase currents (first phase currents) corresponding to the multi-phase power distribution line in real time, and determine whether to start the power distribution line distance protection process according to the plurality of first phase currents. The multi-phase power distribution line can be three-phase lines in a three-phase system, which are A-phase line, B-phase line and C-phase line, and the first phase currents can be represented as I A , I B and I C , respectively.

[0052] The line protection device can be any line protection device in a power system.

[0053] For example, continuing to refer to Figure 1 , the line protection device can be line protection device 1, line protection device 2 or line protection device 3.

[0054] Step S202: Determine a plurality of first line currents according to the plurality of first phase currents, the plurality of first line currents being the same in number as the plurality of first phase currents.

[0055] The line protection device can obtain a plurality of phase currents (i.e. first phase currents) corresponding to the multi-phase power distribution line in real time, and calculate a plurality of line currents (i.e. first line currents) in real time according to the plurality of phase currents.

[0056] For example, the plurality of phase currents can be currents flowing through the A-phase line, the B-phase line and the C-phase line, represented as I A , I B and I C , respectively, and the plurality of line currents can be differences between currents in the conductors corresponding to the A-phase line and the B-phase line, differences between currents in the conductors corresponding to the B-phase line and the C-phase line, and differences between currents in the conductors corresponding to the C-phase line and the A-phase line, represented as I AB , I BC and I CA , respectively. Wherein, I AB =I A -I B ; I BC =I B -I C ; I CA =I C -IA .

[0057] Step S203: judging whether there is a line current greater than or equal to the preset overcurrent setting value in the plurality of first line currents.

[0058] The line protection device can be pre-configured with the preset overcurrent setting value I set When the power distribution line is in normal operation, the line current of the power distribution line usually does not exceed the rated line current of the protection device. When the line current exceeds the rated line current, the probability of the power distribution line being in a short-circuit fault state is higher. Therefore, the preset overcurrent setting value can be a value greater than the rated line current. For example, the preset overcurrent setting value can be 1.2 times the rated line current. The present application does not limit the specific multiple relationship between the preset overcurrent setting value and the rated line current.

[0059] In some embodiments, the line protection device can also set the preset overcurrent setting value according to the estimated current size when the line is in a fault state.

[0060] If there is a line current greater than or equal to the preset overcurrent setting value in the plurality of first line currents, the line protection device performs step S204. If there is no line current greater than or equal to the preset overcurrent setting value in the plurality of first line currents, the line protection device does not need to perform subsequent steps until there is a line current greater than or equal to the preset overcurrent setting value in the plurality of line currents obtained, and then the distance protection process of the power distribution line is started.

[0061] Step S204: If there is a line current greater than or equal to the preset overcurrent setting value in the plurality of first line currents, the first time is recorded as the fault time, and the phase corresponding to the line current with the largest current amplitude in the plurality of first line currents is determined as the fault phase.

[0062] For example, if I AB , I BC , and I CA , I AB has the largest current amplitude, the line protection device can determine that the AB phase is the fault phase; if I BC has the largest current amplitude, the line protection device can determine that the BC phase is the fault phase; and if I CA has the largest current amplitude, the line protection device can determine that the CA phase is the fault phase.

[0063] After the line protection device determines that the power distribution line is in a fault state and determines the fault phase, it can determine whether to perform a distance protection action. Figure 3 A distance protection process schematic diagram of a power distribution line distance protection method provided by an embodiment of the present application is shown in FIG. 2. As shown in FIG. 2, the process of the line protection device performing distance protection can include the following steps: Figure 3

[0064] ​Step S301: obtaining a first measured impedance corresponding to the fault phase type, and obtaining a preset unit reactance value and a preset differential time.

[0065] The determination method of the fault phase type can refer to the above Figure 2 The determination method of the fault phase type in the corresponding embodiment will not be repeated here.

[0066] The line protection device can be a first line protection device, and the first line protection device is configured to monitor a line state of a first line section.

[0067] For example, continuing to refer to Figure 1 , if the first line protection device is the line protection device 1, the first line section is the distribution line 1; if the first line protection device is the line protection device 2, the first line section is the distribution line 2; if the first line protection device is the line protection device 3, the first line section is the distribution line 3.

[0068] The line protection device can determine the first measured impedance according to a second line voltage and a second line current corresponding to the fault phase type obtained at a second time. Specifically, the first measured impedance may be a ratio of the second line voltage to the second line current.

[0069] That is, ;

[0070] wherein, represents the fault phase type, when the fault phase type is the AB phase, is AB; when the fault phase type is the BC phase, is BC; when the fault phase type is the CA phase, is CA. represents the second line voltage, represents the second line current.

[0071] The second time can be any time (first time) after the fault time, or can be the fault time (first time). It should be understood that before starting the distance protection process, if it is detected that there is a line fault (there is a line current greater than or equal to a preset overcurrent setting value in the plurality of first line currents), the line protection device starts the distribution line distance protection process and executes step S301.

[0072] The preset unit reactance value X1 can be a preset unit line length corresponding reactance estimation value, and the preset unit reactance value X1 can be an empirical value. For example, the preset unit reactance value X1 can be 0.3-0.6 Ω / km, for example, X1=0.3 Ω / km, and the specific value of the preset unit reactance value X1 is not limited in the present application.

[0073] The preset differential time T setThe difference between the action time set on the line protection devices of the two adjacent lines can be, for example, if the action time set on the line protection devices from the load side to the power supply side is 0.1s, 0.2s, 0.3s, 0.4s and 0.5s respectively, the preset level difference time T set is 0.1s.

[0074] Step S302: determining a target impedance rate according to the preset unit inductive reactance value, the preset level difference time and the first time interval, the target impedance rate being positively correlated with the preset unit inductive reactance value, the target impedance rate being negatively correlated with the preset level difference time, the starting time of the first time interval being the fault time, and the ending time of the first time interval being the current time.

[0075] In the embodiments of the present application, the line protection device performing the power distribution line distance protection method can be a first line protection device, the first line protection device being any one of the line protection devices in the power distribution line, the first line protection device being configured to monitor the line state of a first line section, the line length corresponding to the first line section being a first line length L1. The line protection device adjacent to the first line protection device is a second line protection device, the second line protection device being configured to monitor the line state of a second line section, the line length corresponding to the second line section being a second line length L2.

[0076] When the first line protection device has an adjacent lower-level line protection device, the second line length L2 is the line length of the second line section monitored by the second line protection device. If there is no second line protection device, the first line protection device can assign the value of the first line length L1 to the second line length L2.

[0077] For example, continuing to refer to Figure 1 , if the first line protection device is the line protection device 1, the first line length is 2km and the second line length is 3km; if the first line protection device is the line protection device 2, the first line length is 3km and the second line length is 4km; if the first line protection device is the line protection device 3, the first line length is 4km, and since the line protection device 3 has no adjacent lower-level line protection device, the line protection device 3 can assign the first line length to the second line length, and the second line length is also 4km.

[0078] In the embodiments of the present application, the current time can be a second time T2, and if the fault time is T1, the first time interval t = T2-T1. The first line protection device determines the target impedance rate according to the preset unit inductive reactance value X1, the preset level difference time T set and the first time interval t. The method for determining the target impedance rate can include: if the first time interval t is less than or equal to the preset level difference time T set, the first line protection device determines a target impedance rate as a first ratio k1 of a preset unit inductance value X1 and the first line length L1 over the preset differential time T set . If the first time interval t is greater than the preset differential time T set and less than or equal to twice the preset differential time 2T set , the first line protection device determines a target impedance rate as a second ratio k2 of the preset unit inductance value X1 and the second line length L2 over the preset differential time T set . If the first time interval is greater than twice the preset differential time 2T set , the first line protection device determines a target impedance rate as a smaller value k3 of the first ratio k1 and the second ratio k2.

[0079] That is, when the first time interval t is less than or equal to the preset differential time T set and greater than or equal to 0, a calculation formula of the target impedance rate is:

[0080] Formula 1;

[0081] If the first time interval t is greater than the preset differential time T set and less than or equal to twice the preset differential time, a calculation formula of the target impedance rate is:

[0082] Formula 2;

[0083] If the first time interval is greater than twice the preset differential time, a calculation formula of the target impedance rate is:

[0084] Formula 3.

[0085] Step S303: determining a target inductance value and a target impedance value according to the target impedance rate, the target inductance value and the target impedance value being positively correlated with the target impedance rate.

[0086] In the embodiment of the application, the method for determining the target inductance value X set according to the target impedance rate by the first line protection device can include: if the first time interval t is less than or equal to the preset differential time T set , determining the target inductance value X set as a product of the target impedance rate k1 and the first time interval t. If the first time interval t is greater than the preset differential time T set and less than or equal to twice the preset differential time 2T set , determining the target inductance value X setis the sum of a first addition term and a second addition term, the first addition term is a product of a preset unit inductive reactance value X1 and the first line length L1, the second addition term is a product of the first time interval t minus a preset step time T from a target inductive reactance value X set . If the first time interval t is greater than twice the preset step time 2T set , the target inductive reactance value X set is the sum of a third addition term and a fourth addition term, the third addition term is a product of a sum of the first line length L1 and the second line length L2 and the preset unit inductive reactance value X1, the fourth addition term is a product of the first time interval t minus twice the preset step time 2T set from a target impedance rate k3.

[0087] That is, when the first time interval t is less than or equal to the preset step time T set , and greater than or equal to 0, the first line protection device can calculate the target inductive reactance value X set by the target impedance rate k1 calculated by the above formula 1, and the calculation formula of the target inductive reactance value X set is:

[0088] Formula 4;

[0089] If the first time interval t is greater than the preset step time T set , and less than or equal to twice the preset step time 2T set , the first line protection device can calculate the target inductive reactance value X set by the target impedance rate k2 calculated by the above formula 2, and the calculation formula of the target inductive reactance value X set is:

[0090] Formula 5;

[0091] If the first time interval t is greater than twice the preset step time 2T set , the first line protection device can calculate the target inductive reactance value X set by the target impedance rate k3 calculated by the above formula 1, formula 2 and formula 3, and the calculation formula of the target inductive reactance value X set is:

[0092] Formula 6;

[0093] The first line protection device can determine a target impedance value according to the target impedance rate and a preset ratio coefficient, the target impedance value is positively correlated with the target inductive reactance value and the preset ratio coefficient. Specifically, the target impedance value R set may be the target inductive reactance value Xset a product of the preset ratio coefficient kr and the target impedance value R

[0094] i.e. the target impedance value R set = kr x X set Equation 7

[0095] The preset ratio coefficient kr can be a ratio coefficient of the target impedance value R set , the preset ratio coefficient kr is greater than 1, and the preset ratio coefficient kr can be used to increase the transition resistance short-circuit fault resistance of the distance protection. It should be understood that the greater the preset ratio coefficient kr, the stronger the transition resistance short-circuit fault resistance. Exemplarily, the preset ratio coefficient kr can be 10, or other values, which are not limited herein.

[0096] Step S304: If the absolute value of the real part impedance of the first measured impedance is less than the target impedance value, and the absolute value of the imaginary part reactance of the first measured impedance is less than the target reactance value, a disconnecting instruction is sent to the circuit breaker, the disconnecting instruction being used to instruct the circuit breaker to change the line state to a disconnected state.

[0097] The first line protection device can determine whether to perform the action of isolating the fault area according to the first measured impedance. Specifically, the first line protection device can determine whether the first measured impedance falls into a protection area composed of the target reactance value X set and the target impedance value R set according to the real part impedance Rm and the imaginary part reactance Xm of the first measured impedance. If the first measured impedance satisfies the instantaneous action condition 1 and the instantaneous action condition 2 at the same time, the first line protection device can determine whether the first measured impedance falls into the protection area composed of the target reactance value X set and the target impedance value R set . The instantaneous action condition 1 and the instantaneous action condition 2 are respectively:

[0098] The instantaneous action condition 1: the absolute value |Rm| of the real part impedance of the first measured impedance is less than the target impedance value R set , i.e. |Rm| < R set .

[0099] The instantaneous action condition 2: the absolute value |Xm| of the imaginary part reactance of the first measured impedance is less than the target reactance value X set , i.e. |Xm| < X set .

[0100] Figure 4 Fig. 1 is a schematic diagram of a protection action area of a power distribution line distance protection method provided by an embodiment of the present application. The horizontal (real part impedance direction) range of the protection action area is from -R set to R setthe longitudinal direction (imaginary part of the inductive reactance direction) of the protection action area is in the range of to the range of. If the first measurement impedance satisfies the instantaneous action condition 1 and the instantaneous action condition 2 at the same time, it indicates that the first measurement impedance falls within the dashed line area shown in the figure, and the first line protection device can set the distribution line distance protection action flag to 1; if the first measurement impedance cannot satisfy the instantaneous action condition 1 and the instantaneous action condition 2 at the same time, it indicates that the first measurement impedance does not fall within the dashed line area shown in the figure, and the first line protection device can set the distribution line distance protection action flag to 0.

[0101] In the embodiments of the present application, when the distribution line distance protection action flag is 1, the first line protection device can send an opening instruction to the circuit breaker corresponding to the three-phase line, and the first line protection device can isolate the fault area.

[0102] Continuing to refer to Figure 1 , if a phase-to-phase short-circuit fault occurs at the point F1, the line protection device 3 is closest to the fault point F1, and the line protection device 1 is farthest from the fault point. The first measurement impedance measured by the line protection device 1 is the largest, and the first measurement impedance measured by the line protection device 3 is the smallest. According to the formulas 1 to 7, as the first time interval gradually increases, the target inductive reactance value X set and the target impedance value R set of the line protection devices 1 to 3 gradually increase, that is, the protection area composed of the target inductive reactance value X set and the target impedance value R set gradually increases, and the line protection device 3 closest to the fault point F1 first satisfies the instantaneous action condition 1 and the instantaneous action condition 2, so the line protection device 3 closest to the fault point F1 first acts to send an opening instruction to the circuit breaker corresponding to the three-phase line to isolate the fault area, which can avoid overstepping misoperation of the line protection device or refusal of the line protection device, and realize accurate fault area isolation.

[0103] When the distribution line distance protection action flag is 0, the first line protection device does not act, which can avoid overstepping misoperation of the line protection device.

[0104] In some embodiments, to avoid misoperation of the line protection device caused by single-time judgment error, the first line protection device can further set a preset time period Td, and if the distribution line distance protection action flag is continuously 1 within the preset time period Td, the first line protection device sends an opening instruction to the circuit breaker corresponding to the three-phase line to isolate the fault area.

[0105] Specifically, after the first measurement impedance satisfies the instantaneous action condition 1 and the instantaneous action condition 2 at the same time, the first line protection device can maintain the current target inductive reactance value X set and the target impedance value R setInvariable, that is, keeping the range of the protection area unchanged, a plurality of second measurement impedances corresponding to the fault phase are continuously acquired within a preset time period Td based on a preset sampling frequency, the preset time period Td is a time period after the current time and spaced from the current time by a second time interval. Exemplarily, the time length corresponding to the preset time period Td can be 5s, or can be other time values, which are not limited in the present application.

[0106] If the power distribution line distance protection action flag is continuously 1 within the preset time period, that is, the absolute values of the real part impedances of the plurality of second measurement impedances are all less than the target impedance value, and the absolute values of the imaginary part reactances of the plurality of second measurement impedances are all less than the target reactance value, the first line protection device can send a disconnecting instruction to the circuit breaker.

[0107] The present application can improve the accuracy and reliability of the action of the first line protection device by setting the preset time period.

[0108] In the technical scheme provided by the embodiments of the present application, the first line protection device can determine a target impedance rate according to the preset unit reactance value, the preset differential time and a first time interval after acquiring the first measurement impedance corresponding to the fault phase, and the preset unit reactance value, the preset differential time and the first time interval. The target impedance rate is positively correlated with the preset unit reactance value, and the target impedance rate is negatively correlated with the preset differential time. The starting time of the first time interval is the fault time, and the ending time of the first time interval is the current time. Then, the target reactance value and the target impedance value are determined according to the target impedance rate, and the target reactance value and the target impedance value are both positively correlated with the target impedance rate. If the absolute value of the real part impedance of the first measurement impedance is less than the target impedance value, and the absolute value of the imaginary part reactance of the first measurement impedance is less than the target reactance value, a disconnecting instruction is sent to the circuit breaker, and the disconnecting instruction is used to instruct the circuit breaker to change the line state to a disconnected state. The technical scheme provided by the embodiments of the present application can determine the specific area where the fault point is located when the power distribution line fails, so that the line protection device closest to the fault point acts, without the need to accurately measure the line parameters of the protection line and without being affected by the length of the line, which can improve the reliability of the action of the line protection device, realize the minimization of the isolation of the fault area, and improve the reliability of the operation of the power distribution line.

[0109] It should be understood that, without logical conflicts, each of the above application embodiments can be combined with each other to adapt to actual application requirements. These combined embodiments or implementation schemes still belong to the protection scope of the present application.

[0110] Corresponding to the power distribution line distance protection method in the above embodiment, an embodiment of the present application provides a power distribution line distance protection device 50, which can be a first line protection device, and the first line protection device is used to monitor the line state of the first line section. The power distribution line distance protection device 50 can be realized by software, hardware or a combination of the two to become part or all of a computer device, and is used to execute the steps in the power distribution line distance protection method in the above embodiment.

[0111] Figure 5 A structure diagram of a power distribution line distance protection device provided by an embodiment of the present application is shown, and only parts related to the embodiment of the present application are shown for ease of description.

[0112] With reference to Figure 5 The power distribution line distance protection device 50 includes an acquisition module 510 and a determination module 520.

[0113] The acquisition module 510 is used to acquire the first measurement impedance corresponding to the fault phase, and acquire the preset unit reactance value and the preset differential time.

[0114] The determination module 520 is used to determine a target impedance rate according to the preset unit reactance value, the preset differential time and a first time interval, the target impedance rate is positively correlated with the preset unit reactance value, the target impedance rate is negatively correlated with the preset differential time, the starting time of the first time interval is the fault time, and the ending time of the first time interval is the current time.

[0115] The determination module 520 is also used to determine a target reactance value and a target impedance value according to the target impedance rate, and the target reactance value and the target impedance value are both positively correlated with the target impedance rate. If the absolute value of the real part impedance of the first measurement impedance is less than the target impedance value, and the absolute value of the imaginary part reactance of the first measurement impedance is less than the target reactance value, a disconnecting instruction is sent to the circuit breaker, and the disconnecting instruction is used to instruct the circuit breaker to change the line state to a disconnected state.

[0116] In some embodiments, the determination module 520 is specifically configured to: based on a preset sampling frequency, continuously acquire a plurality of second measurement impedances corresponding to the fault phase within a preset time period, and the preset time period is a time period after the current time and spaced from the current time by a second time interval.

[0117] In some embodiments, the determination module 520 is specifically configured to: if the absolute values of the real part impedances of the plurality of second measurement impedances are all less than the target impedance value, and the absolute values of the imaginary part reactances of the plurality of second measurement impedances are all less than the target reactance value, a disconnecting instruction is sent to the circuit breaker.

[0118] In some embodiments, the acquisition module 510 is specifically configured to: acquire a plurality of first line currents at a first time, the first time being any time before the first line protection device starts the distance protection process. If there is a line current greater than or equal to a preset overcurrent setting value in the plurality of first line currents, the first time is recorded as the fault time, and the phase corresponding to the line current with the largest current amplitude in the plurality of first line currents is determined as the fault phase. Acquire the second line voltage and the second line current corresponding to the fault phase at a second time. Determine the ratio of the second line voltage to the second line current as the first measured impedance.

[0119] In some embodiments, the first line section corresponds to a first line length, and the lower-level line protection device adjacent to the first line protection device is a second line protection device, the second line protection device being configured to monitor the line state of a second line section, the second line section corresponding to a second line length. The determination module 520 is specifically configured to: if the first time interval is less than or equal to a preset level difference time, determine the target impedance rate as a first ratio of a preset unit inductance value multiplied by the first line length to the preset level difference time. If the first time interval is greater than the preset level difference time and less than or equal to twice the preset level difference time, determine the target impedance rate as a second ratio of the preset unit inductance value multiplied by the second line length to the preset level difference time. If the first time interval is greater than twice the preset level difference time, determine the target impedance rate as the smaller of the first ratio and the second ratio.

[0120] In some embodiments, the determination module 520 is specifically configured to: if the first time interval is less than or equal to the preset level difference time, determine the target inductance value as the product of the target impedance rate and the first time interval. If the first time interval is greater than the preset level difference time and less than or equal to twice the preset level difference time, determine the target inductance value as the sum of a first added term and a second added term, the first added term being the product of the preset unit inductance value and the first line length, and the second added term being the product of the difference between the first time interval and the preset level difference time and the target impedance rate. If the first time interval is greater than twice the preset level difference time, determine the target inductance value as the sum of a third added term and a fourth added term, the third added term being the product of the sum of the first line length and the second line length and the preset unit inductance value, and the fourth added term being the product of the difference between the first time interval and twice the preset level difference time and the target impedance rate. According to the target impedance rate and a preset ratio coefficient, determine the target impedance value, the target impedance value being positively correlated with the target inductance value and the preset ratio coefficient.

[0121] In some embodiments, if there is no second line protection device, the value of the first line length is assigned to the second line length.

[0122] In some embodiments, the target impedance value is the product of the target inductance value and the preset ratio coefficient.

[0123] It should be noted that the information interaction, execution process and the like between the above apparatuses / units are based on the same concept as the method embodiments of the present application, and the specific functions and the brought technical effects can be referred to the method embodiments part, which will not be repeated here.

[0124] It should be understood that the size of the serial number of each step in the above embodiments does not mean the order of execution, and the execution order of each process should be determined according to its function and inherent logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0125] Based on the same inventive concept, the embodiments of the present application also provide an electronic device.

[0126] Figure 6 is a structural schematic diagram of an electronic device provided by the embodiments of the present application. As shown in Figure 6 , the electronic device 60 of this embodiment includes at least one processor 610 (only one is shown in Figure 6 ), a memory 620, and a communication module 640, and the memory 620 stores a computer program 630 that can run on the processor 610. The processor 610 implements the steps in the power distribution line distance protection method embodiments when executing the computer program 630, such as Figure 2 steps S201 to S204 shown in Figure 3 or steps S301 to S304 shown in. Alternatively, the processor 610 implements the functions of each module / unit in each of the above apparatus embodiments when executing the computer program 630, such as Figure 5 the functions of the modules 510 to 520 shown in, and the communication module 640 can be a separate communication unit for communicating with an external server or terminal device.

[0127] The electronic device 60 can include, but is not limited to, the processor 610 and the memory 620. Those skilled in the art can understand that Figure 6 the electronic device 60 is only an example and does not constitute a limitation on the electronic device 60, and can include more or fewer components than shown, or combine certain components, or different components, for example, the electronic device 60 can also include an input sending device, a network access device, a bus, etc.

[0128] The processor 610 can be a central processing unit (CPU), and can also be other general-purpose processors, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or the like. The general-purpose processor can be a microprocessor or the processor can also be any conventional processor.

[0129] The memory 620 can be an internal storage unit of the electronic device 60, such as a hard disk or a memory of the electronic device 60 in some embodiments. The memory 620 can also be an external storage device of the electronic device 60, such as a plug-in hard disk, a smart media card (SMC), a secure digital (SD) card, a flash card, or the like equipped on the electronic device 60. The memory 620 can also include both the internal storage unit and the external storage device of the electronic device 60. The memory 620 is used to store an operating system, an application program, a boot loader, data, and other programs, such as program codes of the computer program 630. The memory 620 can also be used to temporarily store data that has been transmitted or will be transmitted.

[0130] In addition, it can be clearly understood by those skilled in the art that, for the convenience and brevity of description, only the division of the above functional units and modules is taken as an example for description, and in actual application, the above functions can be completed by different functional units and modules according to needs, that is, the internal structure of the apparatus is divided into different functional units or modules to complete all or part of the above described functions. The functional units in each embodiment of the present application can be integrated in one processing unit, or each unit can be physically present separately, or two or more units can be integrated in one unit. The integrated unit can be realized in the form of hardware or in the form of a software functional unit.

[0131] The embodiments of the present application provide 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 each method embodiment.

[0132] The embodiment of the present application provides a chip, the chip includes a processor and a memory, the computer program is stored in the memory, and the computer program is executed by the processor to realize the steps in each method embodiment.

[0133] The embodiment of the present application provides a computer program product, when the computer program product runs on an electronic device, the electronic device executes the steps in each method embodiment.

[0134] It should be understood that the processor mentioned in the embodiment of the present application can be a central processing unit (CPU), and can also be other general-purpose processors, digital signal processors (DSP), application specific integrated circuits (ASIC), ready programmable gate arrays (FPGA) or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components, etc. The general-purpose processor can be a microprocessor or the processor can also be any conventional processor, etc.

[0135] It should also be understood that the memory mentioned in the embodiments of the present application can be a volatile memory or a non-volatile memory, or can include both volatile and non-volatile memories. Among them, the non-volatile memory can be a read-only memory (Read-only Memory, ROM), a programmable read-only memory (Programmable ROM, PROM), an erasable programmable read-only memory (Erasable PROM, EPROM), an electrically erasable programmable read-only memory (Electrically EPROM, EEPROM) or a flash memory. The volatile memory can be a random access memory (Random access Memory, RAM) used as an external cache. By way of example but not limitation, many forms of RAM are available, such as static random access memory (Static RAM, SRAM), dynamic random access memory (Dynamic RAM, DRAM), synchronous dynamic random access memory (Synchronous DRAM, SDRAM), double data rate synchronous dynamic random access memory (Double Data Rate SDRAM, DDR SDRAM), enhanced synchronous dynamic random access memory (Enhanced SDRAM, ESDRAM), synchronous link dynamic random access memory (Synchlink DRAM, SLDRAM) and direct memory bus random access memory (Direct Rambus RAM, DR RAM).

[0136] Those skilled in the art can clearly understand that, for the convenience and brevity of description, only the above-mentioned division of each functional unit and module is exemplified, and in actual application, the above-mentioned functions can be completed by different functional units and modules according to needs, that is, the internal structure of the device is divided into different functional units or modules to complete all or part of the functions described above. Each functional unit and module in the embodiment can be integrated in one processing unit, or each unit can exist physically, or two or more units can be integrated in one unit, and the integrated unit can be realized in the form of hardware or software. In addition, the specific name of each functional unit and module is only for easy distinction, and does not limit the protection scope of the present application. The specific working process of the unit and module in the above system can refer to the corresponding process in the foregoing method embodiments, which will not be repeated here.

[0137] In the above embodiments, the description of each embodiment has its own emphasis, and the parts not described or recorded in detail in a certain embodiment can be referred to the related description of other embodiments.

[0138] Those skilled in the art can understand that the units and algorithm steps of each example described in combination with the embodiments disclosed herein can be realized in electronic hardware or a combination of computer software and electronic hardware. Whether the functions are realized in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to realize the described functions for each specific application, but such implementation should not be considered beyond the scope of the present application.

[0139] In the embodiments provided in the present application, it should be understood that the disclosed apparatus and method can be implemented in other ways. For example, the above-described system embodiments are merely illustrative. For example, the division of the modules or units is only a logical function division, and there can be another division manner in actual implementation. For example, a plurality of units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the coupling or direct coupling or communication connection between the units shown or discussed can be indirect coupling or communication connection through some interface, device or unit, and can be electrical, mechanical or other forms.

[0140] The units described as separate components can or can not be physically separated, and the components shown as units can or can not be physical units, i.e. they can be located in one place or distributed on a plurality of network units. Part or all of the units can be selected according to actual needs to achieve the purpose of the embodiments.

[0141] In addition, each functional unit in each embodiment of the present application can be integrated into a processing unit, or each unit can exist physically independently, or two or more units can be integrated into one unit. The integrated unit can be realized in the form of hardware or in the form of a software functional unit.

[0142] The integrated unit, if implemented in the form of a software function unit and sold or used as an independent product, can be stored in a computer readable storage medium. Based on such understanding, the present application can implement all or part of the processes in the above-mentioned embodiment methods through a computer program to instruct related hardware to complete, and the computer program can be stored in a computer readable storage medium. When the computer program is executed by a processor, the steps of the above-mentioned various method embodiments can be implemented. The computer program includes computer program code, which can be in the form of source code, object code, executable files or some intermediate forms, etc. The computer readable medium at least includes any entity or device capable of carrying the computer program code to the large screen device, recording medium, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signal, telecommunication signal and software distribution medium. For example, U disk, mobile hard disk, magnetic disk or optical disk, etc. In some jurisdictions, according to legislation and patent practice, the computer readable medium cannot be an electrical carrier signal and a telecommunication signal.

[0143] Finally, it should be noted that: the above is only a specific implementation of the present application, but the protection scope of the present application is not limited to this, any change or replacement within the technical scope disclosed in the present application should be covered in the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A power distribution line distance protection method characterized by, The method is applied to a first line protection device used for monitoring a line state of a first line section, and comprises the following steps: obtaining a first measured impedance corresponding to a fault phase, and obtaining a preset unit inductance value and a preset differential time; determining a target impedance rate according to the preset unit inductance value, the preset differential time and a first time interval, the target impedance rate being positively correlated with the preset unit inductance value, the target impedance rate being negatively correlated with the preset differential time, a starting time of the first time interval being a fault time, and an ending time of the first time interval being a current time; determining a target inductance value and a target impedance value according to the target impedance rate, the target inductance value and the target impedance value being positively correlated with the target impedance rate; if an absolute value of a real part impedance of the first measured impedance is less than the target impedance value and an absolute value of an imaginary part inductance of the first measured impedance is less than the target inductance value, sending a disconnecting instruction to a circuit breaker, the disconnecting instruction being used for instructing the circuit breaker to change the line state to a disconnected state.

2. The power distribution line distance protection method of claim 1, wherein, Before the step of sending the disconnecting instruction to the circuit breaker, the method further comprises the following steps: continuously obtaining a plurality of second measured impedances corresponding to the fault phase in a preset time period based on a preset sampling frequency, the preset time period being a time period after the current time and spaced from the current time by a second time interval.

3. The power distribution line distance protection method of claim 2, wherein, The step of sending the disconnecting instruction to the circuit breaker comprises the following steps: if absolute values of real part impedances of the plurality of second measured impedances are all less than the target impedance value and absolute values of imaginary part inductances of the plurality of second measured impedances are all less than the target inductance value, sending the disconnecting instruction to the circuit breaker.

4. The power distribution line distance protection method of claim 1, wherein, The step of obtaining the first measured impedance corresponding to the fault phase comprises the following steps: obtaining a plurality of first line currents at a first time, the first time being any time before a distance protection process of the first line protection device is started; if there is a line current greater than or equal to a preset overcurrent setting value in the plurality of first line currents, recording the first time as the fault time, and determining a phase corresponding to a line current with the largest current amplitude in the plurality of first line currents as the fault phase; obtaining a second line voltage and a second line current corresponding to the fault phase at a second time; determining a ratio of the second line voltage to the second line current as the first measured impedance.

5. The power distribution line distance protection method of claim 1, wherein, A line length corresponding to the first line section is a first line length, and a lower-level line protection device adjacent to the first line protection device is a second line protection device, the second line protection device being used for monitoring a line state of a second line section, a line length corresponding to the second line section being a second line length; The step of determining the target impedance rate according to the preset unit inductance value, the preset differential time and the first time interval comprises the following steps: if the first time interval is less than or equal to the preset differential time, determining the target impedance rate as a first ratio value of a product of the preset unit inductance value and the first line length to the preset differential time. if the first time interval is greater than the preset step time and less than or equal to twice the preset step time, the target impedance rate is determined as a second ratio value of the preset unit inductive reactance value and the second line length divided by the preset step time; if the first time interval is greater than twice the preset step time, the target impedance rate is determined as a smaller value between the first ratio value and the second ratio value.

6. The power distribution line distance protection method of claim 5, wherein, The method further comprises: if the first time interval is less than or equal to the preset step time, the target inductive reactance value is determined as a product of the target impedance rate and the first time interval; if the first time interval is greater than the preset step time and less than or equal to twice the preset step time, the target inductive reactance value is determined as a sum of a first added term and a second added term, the first added term being a product of the preset unit inductive reactance value and the first line length, the second added term being a product of a difference between the first time interval and the preset step time and the target impedance rate; if the first time interval is greater than twice the preset step time, the target inductive reactance value is determined as a sum of a third added term and a fourth added term, the third added term being a product of a sum of the first line length and the second line length and the preset unit inductive reactance value, the fourth added term being a product of a difference between the first time interval and twice the preset step time and the target impedance rate; The target inductive reactance value is positively correlated with the target impedance rate and a preset ratio coefficient.

7. The power distribution line distance protection method of claim 5, wherein, if the second line protection device does not exist, the first line length is assigned to the second line length.

8. The power distribution line distance protection method according to any one of claims 1 to 7, characterized by, The target inductive reactance value is positively correlated with the target impedance rate and a preset ratio coefficient.

9. An electronic device, comprising: The computer program is executed by the processor to implement the power distribution line distance protection method as claimed in any one of claims 1-8.

10. A computer-readable storage medium storing a computer program, the computer program comprising instructions that, when executed by a computer, cause the computer to perform the method of any one of claims 1 to 9. The computer program is executed by the processor to implement the power distribution line distance protection method as claimed in any one of claims 1-8.

Images