Fault identification method, electronic device and computer readable storage medium

Abstract

The present application relates to the technical field of relay protection for electric power systems, and in particular to a fault identification method, an electronic device and a computer-readable storage medium, the method comprising: determining the angle of a first equivalent potential, the angle of the first equivalent potential being the angle of the equivalent potential corresponding to the first phase line. Determine a first offset angle according to the angle of the first equivalent potential and the angle of the first positive sequence voltage of the line protection device, the first offset angle being positively correlated with the angle of the first equivalent potential. If the first offset angle is within a first preset angle range, determine a first compensation angle according to the first offset angle, the first compensation angle being positively correlated with the first offset angle. Correct the first initial angle difference according to the first compensation angle to obtain a first corrected angle difference. If the first corrected angle difference is within a second preset angle range, it is determined that there is an intra-zone fault. The present application can improve the accuracy of fault category identification, thereby improving the stability of power system operation.

Description

Technical Field

[0001] The present application relates to the technical field of relay protection for power systems, and in particular to a fault detection method, an electronic device, and a computer-readable storage medium. Background Art

[0002] Distance protection is a commonly used fault protection method in power systems. Its main function is to cut off the faulty power supply by detecting the distance and direction of the fault point when a short circuit or other abnormal situation occurs in the power system, thereby avoiding the expansion of the fault, protecting equipment from damage, and ensuring the safe and stable operation of the power system.

[0003] Phase-comparison distance protection is a common distance protection method. In the traditional phase-comparison distance protection technical solution, the line protection device usually determines whether the fault type is an internal fault or an external fault by the working voltage and polarization voltage of the distance relay. When the phase-comparison angle difference between the working voltage and the polarization voltage is within the angle range of 90°~270°, the line protection device determines that the fault type of the transmission line is an internal fault. If the phase-comparison angle difference between the working voltage and the polarization voltage is not within the angle range of 90°~270°, the line protection device determines that the fault type of the transmission line is an external fault.

[0004] However, with the development of power systems, new energy equipment such as photovoltaic power generation and wind power generation are playing an increasingly important role in power systems. Since new energy equipment such as photovoltaic power generation and wind power generation contain controllable power electronic devices, when a transmission line fails, the controllable power electronic devices are affected by the control strategy, and the operating voltage and polarization voltage are changed compared to the traditional power grid, which makes it impossible for the line protection device to judge the fault type by comparing the phase angle difference, and there are hidden dangers in the stability of the power system operation. Summary of the invention

[0005] The present application provides a fault detection method, device, electronic device and computer-readable storage medium, which can improve the accuracy of fault type identification, thereby improving the stability of power system operation.

[0006] In the first aspect, the present application provides a fault identification method, which is applied to a line protection device, and the line protection device is used to monitor the line state of a multi-phase line. The method includes: determining the angle of a first equivalent potential, the angle of the first equivalent potential is the angle of the equivalent potential corresponding to the first phase line in the multi-phase line, and the first phase line is a phase line in the multi-phase line. Determine a first offset angle according to the angle of the first equivalent potential and the angle of the first positive sequence voltage of the line protection device, and the first offset angle is positively correlated with the angle of the first equivalent potential. If the first offset angle is within a first preset angle range, determine a first compensation angle according to the first offset angle, and the first compensation angle is positively correlated with the first offset angle. Correct the first initial angle difference according to the first compensation angle to obtain a first corrected angle difference, and the first initial angle difference is the difference between the angle of the first working voltage corresponding to the first phase line and the angle of the first positive sequence voltage. If the first corrected angle difference is within a second preset angle range, it is determined that there is an intra-zone fault.

[0007] In some embodiments, the method further includes: if the first offset angle is not within a first preset angle range, and / or the first corrected angle difference is not within a second preset angle range, determining that an out-of-zone fault exists.

[0008] In some embodiments, determining the angle of the first equivalent potential includes: obtaining multiple voltages and multiple currents, where the multiple voltages are operating voltages of the multi-phase line, and the multiple currents are operating currents of the multi-phase line. Determining the zero-sequence current corresponding to the multi-phase line based on the multiple currents. Determining the angle of the first equivalent potential based on the multiple voltages, the multiple currents, and the zero-sequence current.

[0009] In some embodiments, determining the angle of the first equivalent potential according to multiple voltages, multiple currents, and zero-sequence current includes: obtaining an amplitude coefficient of the first equivalent potential, and obtaining a zero-sequence compensation coefficient and a line positive-sequence impedance value, wherein the amplitude coefficient of the first equivalent potential is an amplitude coefficient corresponding to the angle of the first equivalent potential. The angle of the first equivalent potential is determined according to the first equivalent potential amplitude coefficient, the zero-sequence compensation coefficient, the line positive-sequence impedance value, the first voltage, the first current, and the zero-sequence current, wherein the first voltage is a voltage corresponding to the first phase line among the multiple voltages, and the first current is a current corresponding to the first voltage among the multiple currents.

[0010] In some embodiments, determining the first offset angle according to the angle of the first equivalent potential and the angle of the first positive sequence voltage of the line protection device includes: determining the angle of the first positive sequence voltage corresponding to the multi-phase line according to multiple voltages. Determining the first offset angle according to the angle of the first equivalent potential and the angle of the first positive sequence voltage.

[0011] In some embodiments, the angle of the first equivalent potential is the angle of the potential difference between the first phase line and the neutral point in the multi-phase line, and if the first corrected angle difference is within the second preset angle range, it is determined that there is an intra-zone fault, including: if the first corrected angle difference is within the second preset angle range, it is determined that there is an intra-zone fault in the first phase line. Or, the angle of the first equivalent potential is the angle of the potential difference between the first phase line and the second phase line in the multi-phase line, and the second phase line is a phase line in the multi-phase line that is different from the first phase line. If the first corrected angle difference is within the second preset angle range, it is determined that there is an intra-zone fault, including: if the first corrected angle difference is within the second preset angle range, it is determined that there is an intra-zone fault in the first phase line and the second phase line.

[0012] In some implementations, if the first offset angle is within a first preset angle range, the fault direction is determined to be a positive direction. If the first offset angle is not within the first preset angle range, the fault direction is determined to be a negative direction.

[0013] In some embodiments, the first preset angle range includes a first sub-range, a second sub-range, and a third sub-range, the first sub-range is a range between the first angle and the second angle, the second sub-range is a range between the second angle and the third angle, the third sub-range is a range between the third angle and the fourth angle, the angles of the first angle, the second angle, the third angle, and the fourth angle are increased in sequence, the first angle is the smallest angle in the first preset angle range, and the fourth angle is the largest angle in the first preset angle range, and determining the first compensation angle according to the first offset angle includes: if the first offset angle is within the first sub-range, determining the first compensation angle as the first correction angle. If the first offset angle is within the second sub-range, determining the first compensation angle as the product of the first offset angle and the second correction angle. If the first offset angle is within the third sub-range, determining the first compensation angle as the third correction angle, and the angles of the first correction angle, the second correction angle, and the third correction angle are increased in sequence.

[0014] In a second aspect, the present application provides a fault identification device, which may be a line protection device, and the line protection device is used to monitor the line status of a multi-phase line, including a determination module and a correction module.

[0015] The determination module is used to determine the angle of the first equivalent potential, where the angle of the first equivalent potential is the angle of the equivalent potential corresponding to the first phase line in the multi-phase line, and the first phase line is one phase line in the multi-phase line.

[0016] The determination module is further used to determine a first offset angle according to an angle of the first equivalent potential and an angle of a first positive sequence voltage of the line protection device, wherein the first offset angle is positively correlated with the angle of the first equivalent potential.

[0017] The determination module is further used to determine a first compensation angle according to the first offset angle when the first offset angle is within a first preset angle range, and the first compensation angle is positively correlated with the first offset angle.

[0018] The correction module is used to correct the first initial angle difference according to the first compensation angle to obtain a first corrected angle difference, where the first initial angle difference is the difference between the angle of the first working voltage corresponding to the first phase line and the angle of the first positive sequence voltage.

[0019] The determination module is further used to determine that there is an in-zone fault when the first corrected angle difference is within a second preset angle range.

[0020] 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.

[0021] 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 first aspects above.

[0022] In the technical solution provided by the present application, the line protection device can determine the first offset angle according to the angle of the first equivalent potential and the angle of the first positive sequence voltage of the line protection device, and determine the degree to which the phase-to-phase distance protection is affected by the new energy control strategy through the first offset angle. And when the first offset angle is within the first preset angle range, the first compensation angle is determined according to the first offset angle, and the first initial angle difference is corrected by the first compensation angle to obtain the first corrected angle difference. When the phase-to-phase distance protection is highly affected by the new energy control strategy, the first initial angle difference can be corrected to reduce the impact of the new energy control strategy on the phase-to-phase distance protection, and the fault state of the line can be determined by the corrected first corrected angle difference. If the first corrected angle difference is within the second preset angle range, it is determined that there is an intra-zone fault. The accuracy of fault category discrimination can be improved, thereby improving the stability of power system operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. 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 paying any creative work.

[0024] Figure 1 This is a schematic diagram of an application scenario of a fault detection method provided in an embodiment of the present application;

[0025] Figure 2 It is a flowchart of a fault detection method provided by an embodiment of the present application;

[0026] Figure 3 is another flow chart of a fault detection method provided in an embodiment of the present application;

[0027] Figure 4 This is a schematic diagram of an intra-area fault scenario of a fault detection method provided in an embodiment of the present application;

[0028] Figure 5 This is a schematic diagram of an angle difference before correction of a fault detection method provided in an embodiment of the present application;

[0029] Figure 6 It is a schematic diagram of a corrected angle difference of a fault detection method provided in an embodiment of the present application;

[0030] Figure 7 This is another flowchart of a fault detection method provided in an embodiment of the present application;

[0031] Figure 8 is a schematic diagram of a fault detection device provided in an embodiment of the present application;

[0032] Fig. 9 It is a schematic diagram of an electronic device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0033] In the following description, specific details such as specific system structures, technologies, etc. are provided for the purpose of illustration rather than limitation, so as to provide 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 also 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 prevent unnecessary details from obstructing the description of the present application.

[0034] It should be understood that when used in the present specification and the appended claims, the term "comprising" indicates the presence of described features, wholes, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components and / or combinations thereof.

[0035] It should also be understood that the term “and / or” used in the specification and appended claims refers to any and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0036] As used in the specification and appended claims of this application, the term "if" can be interpreted as "when" or "uponce" 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 "uponce it is determined" or "in response to determining" or "uponce [described condition or event] is detected" or "in response to detecting [described condition or event]", depending on the context.

[0037] 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.

[0038] References to "one embodiment" or "some embodiments" etc. described in the specification of this application mean that one or more embodiments of the present application include specific features, structures or characteristics described in conjunction with the embodiment. Therefore, the statements "in one embodiment", "in some embodiments", "in some other embodiments", "in some other embodiments", etc. that appear in different places in this specification do not necessarily refer to the same embodiment, but mean "one or more but not all embodiments", unless otherwise specifically emphasized in other ways. The terms "including", "comprising", "having" and their variations all mean "including but not limited to", unless otherwise specifically emphasized in other ways.

[0039] The network structure of the power system consists of multiple links such as power generation, transmission, distribution and consumption. In this system, the safe and stable operation of power equipment and lines is crucial. In order to protect these equipment and circuits, the power system adopts a variety of protection measures, among which distance protection is one of the important protection methods. Phase-comparison distance protection is a way to implement distance protection. It can use the phase-comparison angle difference between the working voltage and polarization voltage of the distance relay to determine the type of fault (internal fault or external fault). The polarization voltage can be a positive sequence voltage.

[0040] When the phase angle difference between the working voltage and the polarization voltage is close to 180°, the line protection device determines that an in-zone fault has occurred, and the line protection device can control the circuit breaker corresponding to the disconnection fault to avoid the expansion of the fault range. In order to improve the fault tolerance of the judgment result, the phase angle difference range for judging as an in-zone fault can be set, such as 90°≤in-zone fault phase angle difference<270°. When the phase angle difference between the working voltage and the polarization voltage is close to 0°, the line protection device determines that an out-of-zone fault has occurred, and the line protection device does not need to act. In order to improve the fault tolerance of the judgment result, the phase angle difference range for judging as an out-of-zone fault can be set, such as 270°(-90°)≤out-of-zone fault phase angle difference<90°.

[0041] However, since new energy equipment such as photovoltaic power generation and wind power generation contain controllable power electronic devices, when a transmission line fails (in-zone fault or out-of-zone fault), the controllable power electronic devices, under the influence of the control strategy, change the operating voltage and polarization voltage compared with the traditional power grid, resulting in a change in the phase angle difference between the operating voltage and the polarization voltage. For example, when an in-zone metallic fault occurs, the phase angle difference between the operating voltage and the polarization voltage is greater than 270°, which does not meet the conditions for determining it as an in-zone fault phase angle difference. The line protection device will determine the in-zone metallic fault as an out-of-zone fault, that is, it will not control the circuit breaker corresponding to the disconnection fault, and the protection device will be at risk of refusing to operate.

[0042] For another example, when an out-of-zone fault occurs, the phase angle difference between the operating voltage and the polarization voltage is greater than 90°, which does not meet the conditions for determining it as an out-of-zone fault phase angle difference. The line protection device will determine the out-of-zone fault as an in-zone fault, and the line protection device will control the circuit breaker corresponding to the disconnection fault, and the protection device will be at risk of false operation.

[0043] Therefore, affected by the new energy control strategy, the line protection device cannot accurately determine the fault type by comparing the phase angle difference, and there are hidden dangers in the stability of the power system operation.

[0044] In view of this, the embodiments of the present application provide a fault identification method, an electronic device and a computer-readable storage medium, which can correct the phase angle difference under the influence of the new energy control strategy, improve the accuracy of the identification of in-zone and out-of-zone faults, and thus improve the stability of the system operation.

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

[0046] In the technical solution provided in the embodiment of the present application, the line protection device can obtain multiple phase voltages, multiple phase currents, multiple line voltages and multiple line currents corresponding to the multi-phase lines in real time.

[0047] For example, Figure 1 As shown, when the multi-phase lines are: A phase line, B phase line and C phase line, the multiple phase voltages can be: the voltage of the A phase line, the voltage of the B phase line and the voltage of the C phase line, respectively expressed as: U A , U B and U C The multiple phase currents can be: the current flowing through the load of the A phase line, the current flowing through the load of the B phase line, and the current flowing through the load of the C phase line, respectively expressed as: I A ,I B and I CThe multiple line voltages can 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 The multiple line currents can be respectively: the difference between the current in the wire corresponding to the A phase line and the current in the wire corresponding to the B phase line, the difference between the current in the wire corresponding to the B phase line and the current in the wire corresponding to the C phase line, and the difference between the current in the wire corresponding to the C phase line and the current in the wire corresponding to the A phase line, which are respectively expressed as: I AB ,I BC and I CA .

[0048] When the device state of the line protection device is the start state, the line protection device can calculate the equivalent potential behind the line protection device in real time according to multiple phase voltages, multiple phase currents, multiple line voltages and multiple line currents, and distinguish the line fault according to the angle of the equivalent potential. If the device state of the line protection device is the non-start state, the line protection device continues to monitor the device state and does not perform the line fault judgment.

[0049] The line protection device calculates the equivalent potential behind the line protection device according to multiple phase voltages, multiple phase currents, multiple line voltages and multiple line currents, and the process of judging the line fault according to the perspective of the equivalent potential can be as follows: Figure 2 As shown, including:

[0050] Step S201: Acquire multiple voltages and multiple currents, where the multiple voltages are operating voltages of a multi-phase line, and the multiple currents are operating currents of a multi-phase line.

[0051] The multi-phase line may be a three-phase line of the power system, and the multiple voltages may be multiple phase voltages corresponding to the three-phase line, or multiple line voltages corresponding to the three-phase line. The multiple currents may be multiple phase currents corresponding to the three-phase line, or multiple line currents corresponding to the three-phase line. The embodiment of the present application takes the multiple voltages as multiple phase voltages and the multiple currents as multiple phase currents as an example to exemplarily illustrate the process of fault identification.

[0052] For example, when the three-phase lines are A-phase line, B-phase line and C-phase line, the multiple voltages can be: the voltage of the A-phase line, the voltage of the B-phase line and the voltage of the C-phase line, respectively expressed as: U A , U B and U C The multiple currents can be: the current flowing through the load of the A phase line, the current flowing through the load of the B phase line, and the current flowing through the load of the C phase line, respectively expressed as: I A ,I Band I C .

[0053] The line protection device determines in sequence whether there is a fault in the three-phase line, and disconnects the circuit breaker corresponding to the fault when the fault type is an in-zone fault, and does not operate when the fault type is an out-of-zone fault. This application takes the fault determination process of any phase line in the three-phase line by the line protection device as an example to illustrate the fault determination process. For example, this phase line can be the A phase line. It can be understood that the line fault determination method of the B phase line and the C phase line has the same or similar principles as the A phase line, and this application will not elaborate on it here.

[0054] The line protection device can obtain multiple currents corresponding to the multi-phase lines through multiple CTs (Current Transformers, current transformers) and multiple voltages corresponding to the multi-phase lines through multiple PTs (Potential Transformers, voltage transformers). This application does not limit the method of obtaining multiple currents and multiple voltages.

[0055] Step 202: Determine the zero-sequence current corresponding to the multi-phase line according to the multiple currents.

[0056] For example, the zero sequence current 3I 0 The calculation formula can be:

[0057] 3I 0 =I A +I B +I C ;

[0058] I A ,I B ,I C They represent the currents corresponding to the A phase line, the B phase line and the C phase line respectively.

[0059] Optionally, the line protection device may also determine the zero-sequence current corresponding to the multi-phase line by an existing zero-sequence current calculation method, which is not limited in the present application.

[0060] After determining the zero-sequence current, the line protection device can make a fault judgment on the phase A line according to the zero-sequence current and the voltage and current corresponding to the phase A line. The process of the line protection device making a fault judgment on the phase A line can be as follows: Figure 3 As shown, including:

[0061] Step S301: determining an angle of a first equivalent potential, where the angle of the first equivalent potential is an angle of an equivalent potential corresponding to a first phase line in a multi-phase line, where the first phase line is one phase line in the multi-phase line.

[0062] The first phase line is the A phase line, and the line protection device can determine the angle of the first equivalent potential corresponding to the first phase line (A phase line) according to the first voltage, the first current and the zero-sequence current. The first voltage is a voltage corresponding to the first phase line (A phase line) among multiple voltages, and the first current is a current corresponding to the first phase line (A phase line) among multiple currents.

[0063] The line protection device can calculate the angle θ of the first equivalent potential corresponding to the first phase line (phase A line) by the following equation: φ :

[0064] ;

[0065] Among them, E φ Indicates the first equivalent potential corresponding to the first phase line (phase A line), and the first equivalent potential can be composed of the amplitude coefficient of the first equivalent potential and the angle of the first equivalent potential. φ It represents the amplitude coefficient of the first equivalent potential corresponding to the first phase line (phase A line), which is a set constant. Since the amplitude of the generator potential is usually about 1.05 times the rated voltage, α φ The value of can be set to a value greater than 1.05 and less than 1.2 according to the actual situation, for example, φ =1.1, this application applies to α φ The specific value of θ is not limited. φ The angle representing the first equivalent potential corresponding to the first phase line (phase A line) is an unknown number. j represents the complex exponential function.

[0066] U φ Indicates the first voltage (the voltage corresponding to the A phase line), I φ represents the first current (the current corresponding to the A phase line), k Z Indicates the positive sequence impedance of the entire line length, which is a fixed value. 0 Represents zero sequence current, β φ Represents the impedance coefficient corresponding to the equivalent potential, which is an unknown number. L It represents the positive sequence impedance of the entire line length, which is a fixed value.

[0067] In the above equation, only the angle θ of the first equivalent potential corresponding to the first phase line (phase A line) φ The impedance coefficient β corresponding to the equivalent potential φ is an unknown number. The line protection device can calculate the impedance coefficient β corresponding to the equivalent potential through the above equation. φ Solve it and substitute the obtained value into the above equation to obtain the angle θ of the first equivalent potential corresponding to the first phase line (phase A line) φ .

[0068] Step S302: determining a first offset angle according to an angle of the first equivalent potential and an angle of a first positive sequence voltage of the line protection device, wherein the first offset angle is positively correlated with the angle of the first equivalent potential.

[0069] In the embodiment of the present application, the first offset angle may be the angle difference between the first equivalent potential and the first positive sequence voltage. That is, the first offset angle ang1=θ φ -arg(U 1-φ ). Among them, θ φ The angle representing the first equivalent potential, arg(U 1-φ ) represents the angle of the first positive sequence voltage.

[0070] The line protection device may determine the first positive sequence voltage based on a plurality of voltages.

[0071] Exemplarily, the first positive sequence voltage U of phase A corresponding to the multi-phase line 1-φ The calculation formula can be:

[0072] U 1-φ =(U A +a 2 U B +aU C ) / 3;

[0073] U A Indicates the voltage corresponding to phase A, U B Indicates the voltage corresponding to the B phase line, U C represents the voltage corresponding to the C phase line, a represents the positive sequence rotation factor, a=e （j2π / 3） .

[0074] Optionally, the line protection device may also determine the first positive sequence voltage by other methods, which is not limited in the present application.

[0075] When there is a fault in the power system, the angle of the first equivalent potential of the power system is usually close to the angle of the first positive sequence voltage, that is, the first offset angle is usually small. However, when the controllable power electronic devices contained in the new energy equipment in the power system are affected by the control strategy, the angles of the first equivalent potential and the first positive sequence voltage will be affected, causing the first offset angle to become larger. Therefore, the line protection device can determine the degree of influence of the new energy equipment on the distance protection judgment result through the first offset angle.

[0076] Step S303: if the first offset angle is within a first preset angle range, determining a first compensation angle according to the first offset angle, wherein the first compensation angle is positively correlated with the first offset angle.

[0077] Exemplarily, the first preset angle range may be an angle range between -45° (315°) and 135°.

[0078] In the embodiment of the present application, if the first offset angle is within the first preset angle range, it indicates that the angle difference between the angle of the first equivalent potential and the angle of the first positive sequence voltage is within the range of the positive direction fault, and the line protection device can determine that the current fault is a positive direction fault. Since the positive direction fault may be an in-zone fault or an out-zone fault. The reverse direction fault is an out-zone fault. It can be seen that when the first offset angle is within the first preset angle range, the probability that the current fault is an out-zone fault is high.

[0079] The positive fault location of the transmission line can be Figure 4 The fault current direction is shown in .

[0080] If the first offset angle is not within the first preset angle range, it means that the angle difference between the equivalent potential angle and the first positive sequence voltage angle is large, and the line protection device can determine that the current fault is a reverse direction fault (out-of-zone fault).

[0081] The method for the line protection device to determine the first compensation angle according to the first offset angle may be:

[0082] A1: Divide the first preset angle range into multiple sub-ranges, and set multiple different compensation angle calculation methods for the multiple sub-ranges respectively.

[0083] Exemplarily, the first preset angle range can be divided into a first sub-range, a second sub-range and a third sub-range. The first sub-range is the range between the first angle and the second angle, the second sub-range is the range between the second angle and the third angle, and the third sub-range is the range between the third angle and the fourth angle. The angles of the first angle, the second angle, the third angle and the fourth angle increase in sequence, the first angle is the smallest angle in the first preset angle range, and the fourth angle is the largest angle in the first preset angle range.

[0084] For example, when the first preset angle range can be an angle range between -45° (315°) and 135°, the first angle, the second angle, the third angle and the fourth angle can be respectively: -45°, 45°, 105° and 135°, then the first sub-range can be [-45°, 45°], the second sub-range can be (45°, 105°), and the third sub-range can be [105°, 135°].

[0085] A2: If the first offset angle is within the first sub-range, the first compensation angle is determined to be the first correction angle.

[0086] The first correction angle can be close to 0°. If the first offset angle is within the first sub-range, it means that the angle difference between the first equivalent potential angle and the first positive-sequence voltage angle is small, and the influence of new energy equipment on the distance protection judgment result is small. The line protection device can set the first compensation angle to an angle close to 0° or to 0°, that is, if -45°≤ang1≤45°, then ang2=0°, ang1 represents the first offset angle, and ang represents the first compensation angle.

[0087] A3: If the first offset angle is within the second sub-range, the first compensation angle is determined to be the product of the first offset angle and the second correction angle.

[0088] For example, if 45°<ang1<105°, then .

[0089] A4: If the first offset angle is within the third sub-range, the first compensation angle is determined to be the third correction angle, and the angles of the first correction angle, the second correction angle, and the third correction angle are increased in sequence.

[0090] Exemplarily, the third correction angle may be 45°, that is, the first compensation angle is 45°.

[0091] It can be understood that, based on the embodiments of the present application, different calculation rules for the first correction angle, the second correction angle and the third correction angle can be set according to actual conditions to determine the first compensation angle. The present application does not limit the calculation method of the first compensation angle.

[0092] Step S304: correcting the first initial angle difference according to the first compensation angle to obtain a first corrected angle difference, where the first initial angle difference is a difference between an angle of a first operating voltage corresponding to the first phase line and an angle of a first positive sequence voltage.

[0093] In the embodiment of the present application, the first corrected angle difference may be a difference between the first initial angle difference and the first compensation angle.

[0094] The calculation method of the first correction angle difference can be:

[0095] B1: Calculate the first operating voltage of the first phase line (phase A line).

[0096] For example, the first operating voltage U of the first phase line (A phase line) is OP_φ The calculation formula can be:

[0097] U OP_φ =U φ -(I φ +kz×3I 0 )Z set ;

[0098] Among them, Z set Indicates the impedance setting value of distance protection, which is a constant, U φ Indicates the voltage corresponding to the first phase line (phase A line), I φ Indicates the current corresponding to the first phase line (phase A line), 3I 0 represents the zero-sequence current, and kz represents the positive-sequence impedance of the entire line length.

[0099] B2: Determine a first corrected angle difference according to an angle of a first working voltage of a first phase line (A phase line) and an angle of a first positive sequence voltage.

[0100] Exemplarily, the calculation formula of the first correction angle difference ang3 may be:

[0101] ang3=arg(U OP_φ )-arg(U 1_φ )-ang2;

[0102] Among them, arg(U OP_φ ) represents the angle of the first working voltage of the first phase line (phase A line), arg (U 1_φ ) represents the angle of the first positive sequence voltage.

[0103] Step S305: If the first corrected angle difference is within the second preset angle range, it is determined that an intra-zone fault exists.

[0104] In the embodiment of the present application, the second preset angle range may be a range between 90° and 270°. If the first corrected angle difference is within the second preset angle range, the line protection device determines that there is an in-zone fault in the first phase line (phase A line). After determining that there is an in-zone fault in the phase A line, the line protection device may issue a disconnection instruction to the circuit breaker corresponding to the phase A line, instructing to disconnect the circuit breaker corresponding to the faulty phase (phase A line) to prevent the expansion of the fault range.

[0105] In the technical solution provided by the embodiment of the present application, the line protection device can determine the first offset angle according to the angle of the first equivalent potential and the angle of the first positive sequence voltage of the line protection device, and determine the degree to which the phase-to-phase distance protection is affected by the new energy control strategy through the first offset angle. When the first offset angle is within the first preset angle range, the first compensation angle is determined according to the first offset angle, and the first initial angle difference is corrected by the first compensation angle to obtain the first corrected angle difference. When the phase-to-phase distance protection is highly affected by the new energy control strategy, the first initial angle difference can be corrected to reduce the impact of the new energy control strategy on the phase-to-phase distance protection, and the fault state of the line can be determined by the corrected first corrected angle difference. If the first corrected angle difference is within the second preset angle range, it is determined that there is an intra-zone fault. The accuracy of fault category identification can be improved, thereby improving the stability of power system operation.

[0106] When there is an internal fault on the line, if the initial angle difference of the phase-to-phase distance protection is not corrected, the line protection device will misjudge the internal fault as an external fault. Figure 5 The technical solution provided in the embodiment of the present application corrects the first initial angle difference by using the first compensation angle to obtain the following: Figure 6 The first corrected angle difference shown enables the line protection device to identify the fault within the zone and perform a protection action (instructing to disconnect the circuit breaker corresponding to the fault).

[0107] It can be understood that the fault determination method for the B-phase line and the C-phase line has the same or similar determination principle as the fault determination method for the A-phase line. When the line protection device identifies that there is an in-zone fault in the B-phase line, a disconnection instruction is issued to the circuit breaker corresponding to the B-phase line, instructing to disconnect the circuit breaker corresponding to the fault phase (B-phase line). When the line protection device identifies that there is an in-zone fault in the C-phase line, a disconnection instruction is issued to the circuit breaker corresponding to the C-phase line, instructing to disconnect the circuit breaker corresponding to the fault phase (C-phase line) to prevent the expansion of the fault range.

[0108] Optionally, the line protection device can also perform fault identification on the line protection device according to multiple line voltages corresponding to the three-phase line and multiple line currents corresponding to the three-phase line. The process of calculating the equivalent potential behind the line protection device according to the multiple line voltages and multiple line currents and identifying the line fault according to the perspective of the equivalent potential can be as follows: Figure 7 As shown, including:

[0109] Step S701: Acquire multiple line voltages and multiple line currents.

[0110] The multiple line voltages may be the multiple voltages between the three-phase lead wires of the three-phase line in the three-phase line, that is, the voltage between phases, and the line voltage is also called the phase-to-phase voltage. The multiple line currents may be the difference between the currents in any two of the three wires drawn from the power supply by the power system.

[0111] For example, when the three-phase lines are A-phase, B-phase and C-phase, the multiple line voltages can be: the voltage between A-phase and B-phase, expressed as U AB The voltage between the B phase line and the C phase line is expressed as U BC The voltage between the C phase line and the A phase line is expressed as U CA The multiple line currents can be respectively: the difference between the current in the wire corresponding to the A phase line and the current in the wire corresponding to the B phase line, the difference between the current in the wire corresponding to the B phase line and the current in the wire corresponding to the C phase line, and the difference between the current in the wire corresponding to the C phase line and the current in the wire corresponding to the A phase line, which are respectively expressed as: I AB ,I BC and I CA .

[0112] The line protection device determines in turn whether there is a fault on the AB phase line, the BC phase line and the CA phase line, and instructs to disconnect the circuit breaker corresponding to the fault when the fault type is an internal fault, and does not operate when the fault type is an external fault.

[0113] The present application takes the fault identification process of any one of the AB phase line, the BC phase line and the CA phase line by the line protection device as an example to illustrate the fault identification process. For example, the phase line can be the AB phase line. It can be understood that the line fault identification method of the BC phase line and the CA phase line has the same or similar principles as the AB phase line, and the present application will not elaborate on them here.

[0114] The method for the line protection device to obtain multiple line voltages and multiple line currents may be an existing method for obtaining and calculating line voltages and line currents, and this application does not limit this.

[0115] Exemplarily, the line protection device may obtain multiple currents corresponding to the multi-phase lines through multiple CTs, obtain multiple voltages corresponding to the multi-phase lines through multiple PTs, and calculate multiple line voltages and multiple line currents through the multiple currents and the multiple voltages.

[0116] Step S702: determining an angle of a second equivalent potential according to the first line voltage and the first line current.

[0117] The first line voltage may be a voltage corresponding to the AB phase line among the multiple line voltages, and the first line current may be a current corresponding to the AB phase line among the multiple line currents.

[0118] The line protection device can calculate the angle θ of the second equivalent potential by the following equation: φφ :

[0119] ;

[0120] Among them, E φφ represents the second equivalent potential, α φφ Represents the amplitude coefficient of the second equivalent potential, which is a set constant α φφ The value of can be set to a value greater than 1.05 and less than 1.2 according to the actual situation, for example, φφ =1.15, this application applies to α φ The specific value of θ is not limited. φφ The angle representing the second equivalent potential is an unknown number. j represents the complex exponential function.

[0121] U φφ Indicates the first line voltage, I φφ Indicates the first line current. β φφ Represents the impedance coefficient corresponding to the second equivalent potential, which is an unknown number. Z L It represents the positive sequence impedance of the entire line length, which is a fixed value.

[0122] In the above equation, only the angle θ of the second equivalent potential φφ The impedance coefficient β corresponding to the second equivalent potential φφ is an unknown number, the line protection device can calculate the impedance coefficient β corresponding to the second equivalent potential through the above equation φφ Solve it and substitute the obtained value into the above equation to obtain the angle θ of the second equivalent potential φφ .

[0123] Step S703: determining a second positive sequence voltage according to a plurality of line voltages.

[0124] For example, the second positive sequence voltage U of the AB phase 1_φφ The calculation formula can be:

[0125] U 1_φφ =(U AB +a 2 U BC +aU CA ) / 3;

[0126] U AB Indicates the voltage between phase A and phase B, U BC Indicates the voltage between phase B and phase C, U CA represents the voltage between phase C and phase A, a represents the positive sequence rotation factor, a=e（j2π / 3） .

[0127] Optionally, the line protection device may also determine the positive-sequence voltage corresponding to the multi-phase line by an existing positive-sequence voltage calculation method, which is not limited in the present application.

[0128] Step S704: determining a second offset angle according to the angle of the second equivalent potential and the angle of the second positive-sequence voltage, wherein the second offset angle is positively correlated with the angle of the second equivalent potential.

[0129] The second offset angle may be an angular difference between an angle of the second equivalent potential and an angle of the second positive sequence voltage.

[0130] When there is a fault in the power system, the angle of the second equivalent potential of the power system is usually close to the angle of the second positive sequence voltage, that is, the second offset angle is usually small. However, when the controllable power electronic devices contained in the new energy equipment in the power system are affected by the control strategy, the angle of the second equivalent potential and the second positive sequence voltage will be affected, causing the second offset angle to become larger. Therefore, the line protection device can determine the degree of influence of the new energy equipment on the distance protection judgment result through the second offset angle.

[0131] Step S705: if the second offset angle is within the third preset angle range, determining a second compensation angle according to the second offset angle, wherein the second compensation angle is positively correlated with the second offset angle.

[0132] The third preset angle range may be the same as or different from the first preset angle range, and the present application does not limit the specific value of the third preset angle range.

[0133] The method in which the line protection device determines the second compensation angle based on the second offset angle has the same or similar calculation principle as the method in which the line protection device determines the first compensation angle based on the first offset angle in the above steps A1 to A4. The calculation process in the above steps A1 to A4 can be referred to, and this application will not elaborate on it here.

[0134] Step S706: correcting the second initial angle difference according to the second compensation angle to obtain a second corrected angle difference, where the second initial comparison angle difference is the angle difference between the second operating voltage angle and the second positive sequence voltage angle.

[0135] In the embodiment of the present application, the second correction angle difference may be the difference between the second initial angle difference and the second compensation angle. Exemplarily, the calculation method of the second correction angle difference may be:

[0136] C1: Calculate the second working voltage of the AB phase line.

[0137] Exemplarily, the second operating voltage U OP_φφThe calculation formula can be:

[0138] U OP-φφ =U φφ -I φφ ×Z set ;

[0139] Among them, Z set Indicates the impedance setting value of distance protection, which is a constant, U φφ Indicates the first line voltage, I φφ Indicates the first line current.

[0140] C2: Determine the second corrected angle difference according to the angle of the second operating voltage and the angle of the second positive sequence voltage.

[0141] Exemplarily, the calculation formula of the second correction angle difference ang3 may be:

[0142] ang3=arg(U OP-φφ )-arg(U 1-φφ )-ang2;

[0143] Among them, arg(U OP-φφ ) represents the angle of the second operating voltage, arg(U 1-φφ ) represents the angle of the second positive sequence voltage.

[0144] Step S707: If the second corrected angle difference is within a fourth preset angle range, it is determined that an intra-zone fault exists.

[0145] In an embodiment of the present application, the fourth preset angle range may be the same as or different from the second preset angle range, and the present application does not limit the specific value of the fourth preset angle range. If the second corrected angle difference is within the fourth preset angle range, the line protection device determines that there is an in-zone fault in the AB phase line. After the line protection device determines that there is an in-zone fault in the AB phase line, it can issue a disconnection instruction to the circuit breakers corresponding to the A phase line, the B phase line, and the C phase line, instructing to disconnect the circuit breakers corresponding to the A phase line, the B phase line, and the C phase line to prevent the expansion of the fault range.

[0146] It can be understood that the fault determination method of the BC phase line and the CA phase line has the same or similar determination principle as the fault determination method of the AB phase line. When the line protection device identifies that there is an in-zone fault in the BC phase line, a disconnection instruction is issued to the circuit breakers corresponding to the A phase line, the B phase line and the C phase line, instructing to disconnect the circuit breakers corresponding to the A phase line, the B phase line and the C phase line. When the line protection device identifies that there is an in-zone fault in the CA phase line, a disconnection instruction is issued to the circuit breakers corresponding to the A phase line, the B phase line and the C phase line, instructing to disconnect the circuit breakers corresponding to the A phase line, the B phase line and the C phase line, so as to prevent the expansion of the fault range.

[0147] It should be understood that, under the premise of no logical conflict, the above-mentioned various application embodiments can be implemented in combination with each other to meet actual application requirements. The specific embodiments or implementation plans obtained after these combinations still fall within the protection scope of this application.

[0148] Corresponding to the fault identification method in the above embodiment, the embodiment of the present application provides a fault identification device 80, which can be a line protection device. The line protection device is respectively connected to multiple current transformers, and the multiple current transformers are used to collect currents of multi-phase lines. The multiple current transformers correspond one-to-one to the multi-phase lines. The fault identification device 80 can be implemented by software, hardware, or a combination of both to become part or all of a computer device, and is used to execute the steps in the fault identification method in the above embodiment.

[0149] Figure 8 A structural schematic diagram of a fault identification 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.

[0150] Reference Figure 8 The fault identification device 80 includes a determination module 810 and a correction module 820.

[0151] The determination module 810 is used to determine the angle of the first equivalent potential, where the angle of the first equivalent potential is the angle of the equivalent potential corresponding to the first phase line in the multi-phase line, and the first phase line is one phase line in the multi-phase line.

[0152] The determination module 810 is further configured to determine a first offset angle according to an angle of the first equivalent potential and an angle of a first positive sequence voltage of the line protection device, wherein the first offset angle is positively correlated with the angle of the first equivalent potential.

[0153] The determination module 810 is further configured to determine a first compensation angle according to the first offset angle when the first offset angle is within a first preset angle range, wherein the first compensation angle is positively correlated with the first offset angle.

[0154] The correction module 820 is used to correct the first initial angle difference according to the first compensation angle to obtain a first corrected angle difference, where the first initial angle difference is the difference between the angle of the first working voltage corresponding to the first phase line and the angle of the first positive sequence voltage.

[0155] The determination module 810 is further configured to determine that an intra-zone fault exists when the first corrected angle difference is within a second preset angle range.

[0156] In some embodiments, the determination module 810 is further used to determine that an out-of-zone fault exists when the first offset angle is not within a first preset angle range and / or when the first corrected angle difference is not within a second preset angle range.

[0157] In some embodiments, the determination module 810 is specifically used to: obtain multiple voltages and multiple currents, the multiple voltages are the operating voltages of the multi-phase line, and the multiple currents are the operating currents of the multi-phase line. According to the multiple currents, determine the zero-sequence current corresponding to the multi-phase line. Determine the angle of the first equivalent potential according to the multiple voltages, the multiple currents and the zero-sequence current.

[0158] In some embodiments, the determination module 810 is specifically used to: obtain an amplitude coefficient of the first equivalent potential, and obtain a zero-sequence compensation coefficient and a line positive-sequence impedance value, wherein the amplitude coefficient of the first equivalent potential is an amplitude coefficient corresponding to the angle of the first equivalent potential. The angle of the first equivalent potential is determined according to the first equivalent potential amplitude coefficient, the zero-sequence compensation coefficient, the line positive-sequence impedance value, the first voltage, the first current, and the zero-sequence current, wherein the first voltage is a voltage corresponding to the first phase line among multiple voltages, and the first current is a current corresponding to the first voltage among multiple currents.

[0159] In some embodiments, the determination module 810 is specifically configured to: determine the angle of the first positive sequence voltage corresponding to the multi-phase line according to the multiple voltages, and determine the first offset angle according to the angle of the first equivalent potential and the angle of the first positive sequence voltage.

[0160] The angle of the first equivalent potential is the angle of the potential difference between the first phase line and the neutral point in the multi-phase line, and the determination module 810 is specifically used to: if the first corrected angle difference is within the second preset angle range, then determine that there is an intra-zone fault in the first phase line. Or, the angle of the first equivalent potential is the angle of the potential difference between the first phase line and the second phase line in the multi-phase line, and the second phase line is a phase line in the multi-phase line that is different from the first phase line. The determination module 810 is specifically used to: if the first corrected angle difference is within the second preset angle range, then determine that there is an intra-zone fault in the first phase line and the second phase line.

[0161] In some embodiments, the determination module 810 is further configured to: determine the fault direction as a positive direction if the first offset angle is within a first preset angle range, and determine the fault direction as a negative direction if the first offset angle is not within the first preset angle range.

[0162] In some embodiments, the first preset angle range includes a first sub-range, a second sub-range, and a third sub-range, the first sub-range is a range between the first angle and the second angle, the second sub-range is a range between the second angle and the third angle, the third sub-range is a range between the third angle and the fourth angle, the angles between the first angle, the second angle, the third angle, and the fourth angle are increased in sequence, the first angle is the smallest angle in the first preset angle range, and the fourth angle is the largest angle in the first preset angle range, and the determination module 810 is further used to: if the first offset angle is within the first sub-range, determine the first compensation angle as the first correction angle. If the first offset angle is within the second sub-range, determine the first compensation angle as the product of the first offset angle and the second correction angle. If the first offset angle is within the third sub-range, determine the first compensation angle as the third correction angle, and the angles of the first correction angle, the second correction angle, and the third correction angle are increased in sequence.

[0163] 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 the present application. Their specific functions and technical effects can be found in the method embodiment part and will not be repeated here.

[0164] 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 the present application.

[0165] Based on the same inventive concept, an embodiment of the present application also provides an electronic device.

[0166] Fig. 9 Schematic diagram of the structure of the electronic device provided in the embodiment of the present application. Fig. 9 As shown, the electronic device 90 of this embodiment includes: at least one processor 910 ( Fig. 9 Only one is shown in the figure), memory 920, and communication module 940, memory 920 stores a computer program 930 that may be run on processor 910. When processor 910 executes computer program 930, steps in the above-mentioned fault identification method embodiment are implemented, such as Figure 3 Alternatively, when the processor 910 executes the computer program 930, the functions of each module / unit in the above-mentioned device embodiments are implemented, for example Figure 8 The functions of modules 810 to 820 are shown, and the communication module 940 can be a separate communication unit for communicating with an external server or terminal device.

[0167] The electronic device 90 may include, but is not limited to: a processor 910 and a memory 920. Those skilled in the art will appreciate that Fig. 9 It is only an example of the electronic device 90 and does not constitute a limitation of the electronic device 90. 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 90 may also include an input sending device, a network access device, a bus, etc.

[0168] The processor 910 may be a central processing unit (CPU), or 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. A general-purpose processor may be a microprocessor or the processor may be any conventional processor, etc.

[0169] In some embodiments, the memory 920 may be an internal storage unit of the electronic device 90, such as a hard disk or memory of the electronic device 90. The memory 920 may also be an external storage device of the electronic device 90, such as a plug-in hard disk, a smart memory card (Smart Media Card, SMC), a secure digital (Secure Digital, SD) card, a flash card (Flash Card), etc. equipped on the electronic device 90. The memory 920 may also include both an internal storage unit of the electronic device 90 and an external storage device. The memory 920 is used to store an operating system, an application program, a boot loader (BootLoader), data, and other programs, such as program codes of a computer program 930, etc. The memory 920 may also be used to temporarily store data that has been sent or is to be sent.

[0170] 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 assigned to 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 each embodiment of the present application can be integrated into a processing unit, or each unit can exist physically separately, 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.

[0171] 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.

[0172] 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.

[0173] 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 method embodiments.

[0174] It should be understood that the processor mentioned in the embodiments of the present application may be a central processing unit (CPU), or 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. A general-purpose processor may be a microprocessor or the processor may also be any conventional processor, etc.

[0175] 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 memory bus random access memory (Direct Rambus RAM, DR RAM).

[0176] The technicians in the relevant field 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 for illustration. In practical applications, the above-mentioned function allocation can be 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 in a processing unit, or each unit can exist physically separately, or two or more units can be integrated in 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, which will not be repeated here.

[0177] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0178] Those of ordinary skill 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 to be beyond the scope of this application.

[0179] In the embodiments provided in the present 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 only a logical function division. There may be other division methods in actual implementation, 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.

[0180] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0181] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0182] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the present application implements all or part of the processes in the above-mentioned embodiment method, which can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a computer-readable storage medium. When the computer program is executed by the processor, the steps of the above-mentioned various method embodiments can be implemented. Among them, the computer program includes computer program code, and the computer program code can be in source code form, object code form, executable file or some intermediate form. The computer-readable medium may at least include: any entity or device that can carry the computer program code to a large-screen device, a recording medium, a computer memory, a read-only memory (ROM, Read-Only Memory), a random access memory (RAM, Random Access Memory), an electric carrier signal, a telecommunication signal, and a software distribution medium. For example, a USB flash drive, a mobile hard disk, a magnetic disk or an optical disk. In some jurisdictions, according to legislation and patent practice, computer-readable media cannot be electric carrier signals and telecommunication signals.

[0183] 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 thereto. Any changes or substitutions within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A fault identification method, characterized in that: Applied to a line protection device, the line protection device is used to monitor the line status of a multi-phase line, the method comprises: Acquire multiple voltages and multiple currents, wherein the multiple voltages are operating voltages of the multi-phase line, and the multiple currents are operating currents of the multi-phase line; Determining a zero-sequence current corresponding to the multi-phase line according to the multiple currents; Obtaining an amplitude coefficient of a first equivalent potential, as well as a zero-sequence compensation coefficient and a line positive-sequence impedance value, wherein the amplitude coefficient of the first equivalent potential is an amplitude coefficient corresponding to an angle of the first equivalent potential; The angle of the first equivalent potential is determined according to the first equivalent potential amplitude coefficient, the zero-sequence compensation coefficient, the line positive-sequence impedance value, the first voltage, the first current and the zero-sequence current, wherein the first voltage is a voltage corresponding to a first phase line among the multiple voltages, the first current is a current corresponding to the first voltage among the multiple currents, the angle of the first equivalent potential is an angle of an equivalent potential corresponding to the first phase line in the multi-phase line, and the first phase line is a phase line in the multi-phase line; determining an angle of a first positive sequence voltage corresponding to the multi-phase line according to the multiple voltages; determining a first offset angle according to an angle of the first equivalent potential and an angle of the first positive-sequence voltage, wherein the first offset angle is positively correlated with an angle of the first equivalent potential; If the first offset angle is within a first preset angle range, determining a first compensation angle according to the first offset angle, wherein the first compensation angle is positively correlated with the first offset angle; Correcting a first initial angle difference according to the first compensation angle to obtain a first corrected angle difference, where the first initial angle difference is a difference between an angle of a first voltage corresponding to the first phase line and an angle of the first positive sequence voltage; If the first corrected angle difference is within a second preset angle range, it is determined that an intra-zone fault exists.

2. The fault identification method according to claim 1, characterized in that: The method further comprises: If the first offset angle is not within the first preset angle range, and / or the first correction angle difference is not within the second preset angle range, it is determined that an out-of-zone fault exists.

3. The fault identification method according to claim 1, characterized in that: The angle of the first equivalent potential is an angle of a potential difference between a first phase line and a neutral point in the multi-phase line, and if the first corrected angle difference is within a second preset angle range, determining that there is an intra-zone fault includes: If the first corrected angle difference is within a second preset angle range, it is determined that there is an intra-area fault on the first phase line; Or, the angle of the first equivalent potential is the angle of the potential difference between the first phase line and the second phase line in the multi-phase line, and the second phase line is a phase line in the multi-phase line different from the first phase line; If the first corrected angle difference is within a second preset angle range, determining that there is an in-zone fault includes: If the first corrected angle difference is within a second preset angle range, it is determined that there is an intra-zone fault between the first phase line and the second phase line.

4. The fault identification method according to claim 1, characterized in that: If the first offset angle is within the first preset angle range, determining that the fault direction is a positive direction; If the first offset angle is not within the first preset angle range, it is determined that the fault direction is the reverse direction.

5. The fault identification method according to claim 1, characterized in that: The first preset angle range includes a first sub-range, a second sub-range and a third sub-range, the first sub-range is a range between the first angle and the second angle, the second sub-range is a range between the second angle and the third angle, the third sub-range is a range between the third angle and the fourth angle, the first angle, the second angle, the third angle and the fourth angle increase in size in sequence, the first angle is the smallest angle in the first preset angle range, the fourth angle is the largest angle in the first preset angle range, and determining the first compensation angle according to the first offset angle includes: If the first offset angle is within the first sub-range, determining the first compensation angle as a first correction angle; If the first offset angle is within the second sub-range, determining the first compensation angle as the product of the first offset angle and the second correction angle; If the first offset angle is within the third sub-range, the first compensation angle is determined to be a third correction angle, and the first correction angle, the second correction angle, and the third correction angle are increased in order.

6. 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 fault identification method as described in any one of claims 1 to 5.

7. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the fault identification method as described in any one of claims 1 to 5 is implemented.

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