A three-phase power distribution system fault detection method and device

Abstract

The present application provides a fault detection method and device for a three-phase power distribution system, wherein the three-phase power distribution system includes three phase lines and a neutral line; wherein the three phase lines intersect with the neutral line at a neutral point, and the three phase lines include: a first phase line, a second phase line, and a third phase line; and at least one of the three phase lines is connected to the neutral line. The method includes: obtaining the voltage between every two phase lines; determining the voltage between each phase line and the neutral point based on the voltage between every two phase lines; determining the voltage between the neutral line and the neutral point based on the voltage between each phase line and the neutral line, and the voltage between each phase line and the neutral point; and determining whether a neutral line break fault has occurred based on the voltage between the neutral line and the neutral point. The solution provided in the present application is used to improve the accuracy of detecting a neutral line break fault.

Description

Technical Field

[0001] The present application relates to the field of circuit technology, and in particular to a fault detection method and device for a three-phase power distribution system. Background Art

[0002] In a three-phase, four-wire, or three-phase, five-wire low-voltage power distribution system, the neutral line effectively maintains a zero potential at the neutral point. However, if a neutral line break occurs, the neutral point potential shifts, and loads behind the break experience varying degrees of overvoltage, significantly impacting the inverter's normal operation and control performance. Therefore, accurately determining whether a neutral line break has occurred is crucial.

[0003] Currently, a three-phase voltage common-mode component solution is commonly used to detect neutral line break faults. However, this method has poor grid adaptability and may cause false detection in some special scenarios, resulting in low fault detection accuracy. Summary of the Invention

[0004] The present application provides a fault detection method and device for improving the accuracy of detecting a neutral line break fault in a three-phase power distribution system.

[0005] In a first aspect, the present application provides a fault detection method for a three-phase power distribution system, wherein the three-phase power distribution system includes three phase lines and a neutral line; wherein the three phase lines intersect the neutral line at a neutral point, and the three phase lines include: a first phase line, a second phase line, and a third phase line; and at least one of the three phase lines is connected to the neutral line;

[0006] The method includes: obtaining the voltage between every two phase lines; determining the voltage between each phase line and the neutral point based on the voltage between every two phase lines; determining the voltage between the neutral line and the neutral point based on the voltage between each phase line and the neutral line, and the voltage between each phase line and the neutral point; and judging whether a neutral line break fault occurs based on the voltage between the neutral line and the neutral point.

[0007] In this method, by connecting the neutral line and some or all of the phase lines in the three-phase distribution system, the deviation of the voltage on the three phase lines relative to the neutral line voltage and the voltage on the three phase lines relative to the true neutral line voltage in the three-phase distribution system increases. The voltage between the neutral line and the neutral point is calculated based on the voltage between each phase line and the neutral line, and the voltage between each phase line and the neutral point. The voltage can be calculated with high accuracy, thereby improving the accuracy of judging whether a neutral line break fault has occurred based on the voltage. The detection accuracy is high in scenarios such as PE line not being connected, unbalanced three-phase power grid, and harmonics. Therefore, this method has good grid adaptability, can reduce false detection problems, and improve detection accuracy.

[0008] In a possible design, any phase line connected to the neutral line is connected to the neutral line through a resistance element.

[0009] In this method, the phase line and the neutral line are connected in a three-phase power distribution system through a resistance element, which has a very low implementation cost, is simple to operate, and is easy to implement.

[0010] In a possible design, obtaining the voltage between every two phase lines includes: obtaining the voltage between each phase line and the neutral line; and determining the voltage between every two phase lines based on the voltage between each phase line and the neutral line.

[0011] In this method, after obtaining the voltage between each phase line and the neutral line, combined with the vector characteristics of the voltage, the voltage between each two phase lines can be simply and quickly calculated. Therefore, on the basis of improving the detection accuracy, the complexity of the calculation process can be ensured to be very low, which facilitates the subsequent determination of the voltage between each phase line and the neutral point.

[0012] In one possible design, obtaining the voltage between every two phase lines includes: obtaining the voltage between the first phase line and the neutral line, the voltage between the second phase line and the neutral line, and the voltage between the first phase line and the third phase line; determining the voltage between the first phase line and the second phase line based on the voltage between the first phase line and the neutral line and the voltage between the second phase line and the neutral line; determining the voltage between the third phase line and the neutral line based on the voltage between the first phase line and the neutral line and the voltage between the first phase line and the third phase line; determining the voltage between the second phase line and the third phase line based on the voltage between the second phase line and the neutral line and the voltage between the third phase line and the neutral line.

[0013] In this method, after obtaining the voltage between any two phase lines and the neutral line among the three phase lines, and the voltage between any phase line of the any two phase lines and a phase line other than the any two phase lines, combined with the vector characteristics of the voltage, the voltage between each two phase lines and the voltage between any phase line and the neutral line can be simply and quickly calculated. Therefore, on the basis of improving the detection accuracy, the complexity of the calculation process can be ensured to be very low, which facilitates the subsequent determination of the voltage between each phase line and the neutral point.

[0014] In one possible design, the voltage between the first phase line and the second phase line satisfies the following formula:

[0015]

[0016] Wherein, V1 is the voltage between the first phase line and the second phase line, V2 is the voltage between the first phase line and the neutral line, V3 is the voltage between the second phase line and the neutral line, and θ is the phase difference between V2 and V3.

[0017] In this method, a triangle model can be obtained based on the vector diagram of the voltage between each phase line and the neutral line. Combined with the characteristics of the triangle line, the voltage between each two phase lines can be determined simply and quickly.

[0018] In a possible design, the voltage between the third phase line and the neutral line conforms to the following formula:

[0019]

[0020] Wherein, V4 is the voltage between the third phase line and the neutral line, V5 is the voltage between the first phase line and the neutral line, V6 is the voltage between the first phase line and the third phase line, and σ is the phase difference between V5 and V6.

[0021] In this method, after establishing a triangle model based on the voltage between the first phase line and the neutral line, the voltage between the first phase line and the third phase line, and the voltage between the third phase line and the neutral line, the cosine theorem of the triangle line model can be combined to simply and quickly determine the third voltage based on any two of the voltages.

[0022] In one possible design, the voltage between each phase line and the neutral point is determined based on the voltage between each two phase lines, including: constructing a target triangle model in a set coordinate system based on the voltage between each two phase lines, wherein the three side lengths of the target triangle model are the voltage between each two phase lines; determining a target point corresponding to the target triangle model in the set coordinate system, wherein the target point and the line connecting any two endpoints of the target triangle model can form an angle of 120° after intersecting; determining the distance from the target point to each endpoint in the target triangle model; and using the distance from the target point to each endpoint as the voltage value between each phase line and the neutral point.

[0023] In this method, a target triangle model is constructed based on the voltage data between every two phase lines, and a target point used to represent the neutral point is determined based on the target triangle model. This ensures the accuracy of the parameters of the determined neutral point, greatly reduces the error of directly detecting the neutral point voltage, and thus improves the accuracy of detecting line break faults based on the voltage between the neutral point and the neutral line, reducing the problem of false detection.

[0024] In a possible design, if the three internal angles of the target triangular model are all less than 120°, the target point is a Fermat point of the target triangular model; or the target point is an isometric center point of the target triangular model.

[0025] In this method, the isometric center point of a triangle or the Fermat point of a triangle whose three internal angles are all less than 120°, divides the circumference of the point into three equal parts, and its characteristics are the same as those of the neutral point in a three-phase distribution system. Therefore, by calculating the isometric center point or Fermat point of the target triangle model, the voltage of the neutral point can be accurately determined.

[0026] In one possible design, the three side lengths of the target triangle model are the first side length, the second side length and the third side length; in the set coordinate system, the target point corresponding to the target triangle model is determined, including: in the set coordinate system, constructing a first target circle model corresponding to the first side length and a second target circle model corresponding to the second side length, wherein the first target circle model includes the two endpoints of the first side length and the target point, and the second target circle model includes the two endpoints of the second side length and the target point; determining the coordinates of the center of the first target circle model according to the coordinates of the two endpoints of the first side length; and determining the coordinates of the center of the second target circle model according to the coordinates of the two endpoints of the second side length; determining the coordinates of the target point according to the coordinates of the center of the first target circle model and the coordinates of the center of the second target circle model.

[0027] In this method, the target point representing the neutral point in the target triangle model is determined based on the auxiliary circle model (the first target circle model and the second target circle model). The calculation method of the mathematical model can be used to improve the detection accuracy and thus ensure the reliability of the detection results.

[0028] In a possible design, the coordinate origin of the set coordinate system is any endpoint of the target triangle model, and a coordinate axis in the set coordinate system coincides with a side length of the target triangle model at the coordinate origin.

[0029] In this method, a set coordinate system is established based on the target triangle model. The side length and angle relationship of the target triangle model can be combined to simplify the coordinate calculation steps, reduce the amount of data calculation for calculating the relevant coordinates in the coordinate system, and thus determine the coordinates of the target point more quickly and easily.

[0030] In one possible design, the voltage between the neutral line and the neutral point is determined based on the voltage between each phase line and the neutral line, and the voltage between each phase line and the neutral point, including: determining a target difference corresponding to each phase line, wherein the target difference corresponding to the target phase line is the difference between the following two: the voltage between the target phase line and the neutral line, and the voltage between the target phase line and the neutral point; and taking the maximum value of the target differences corresponding to the three phase lines as the voltage between the neutral line and the neutral point.

[0031] In this method, the maximum value of the difference between the three-phase neutral line voltage and the sampled three-phase reference ground (neutral line) voltage is used as the voltage between the neutral line and the neutral point, and fault detection is performed based on this voltage, which can further improve the fault tolerance rate and reduce the problem of false detection.

[0032] In one possible design, whether a neutral line break fault occurs is determined based on the voltage between the neutral line and the neutral point, including: determining whether the voltage between the neutral line and the neutral point is greater than a set threshold; if it is determined that the voltage between the neutral line and the neutral point is greater than the set threshold, determining that a neutral line break fault occurs; otherwise, determining that no neutral line break fault occurs.

[0033] In this method, under normal circumstances, when there is no current flowing on the neutral line in a three-phase power distribution system, the voltage between the neutral line and the neutral point should be zero. If the voltage between the neutral line and the neutral point is not zero, it indicates that the neutral line may be faulty. Therefore, this method can quickly determine whether the neutral line is broken.

[0034] In a second aspect, the present application provides a fault detection device for a three-phase power distribution system, wherein the three-phase power distribution system includes three phase lines and a neutral line; wherein the three phase lines intersect the neutral line at a neutral point, and the three phase lines include: a first phase line, a second phase line, and a third phase line; and at least one of the three phase lines is connected to the neutral line;

[0035] The fault detection device includes a transceiver module and a processing module; the transceiver module is used to obtain the voltage between each two phase lines; the processing module is used to determine the voltage between each phase line and the neutral point based on the voltage between each two phase lines; based on the voltage between each phase line and the neutral line, and the voltage between each phase line and the neutral point, determine the voltage between the neutral line and the neutral point; based on the voltage between the neutral line and the neutral point, determine whether the neutral line has a broken line fault.

[0036] In a possible design, any phase line connected to the neutral line is connected to the neutral line through a resistance element.

[0037] In one possible design, when the transceiver module obtains the voltage between each two phase lines, it is specifically used to: obtain the voltage between each phase line and the neutral line; and determine the voltage between each two phase lines based on the voltage between each phase line and the center line.

[0038] In a possible design, when the transceiver module obtains the voltage between each two phase lines, it is specifically used to: obtain the voltage between the first phase line and the neutral line, the voltage between the second phase line and the neutral line, and the voltage between the first phase line and the third phase line; determine the voltage between the first phase line and the second phase line based on the voltage between the first phase line and the neutral line and the voltage between the second phase line and the neutral line; determine the voltage between the third phase line and the neutral line based on the voltage between the first phase line and the neutral line and the voltage between the first phase line and the third phase line; determine the voltage between the second phase line and the third phase line based on the voltage between the second phase line and the neutral line and the voltage between the third phase line and the neutral line.

[0039] In one possible design, the voltage between the first phase line and the second phase line satisfies the following formula:

[0040]

[0041] Wherein, V1 is the voltage between the first phase line and the second phase line, V2 is the voltage between the first phase line and the neutral line, V3 is the voltage between the second phase line and the neutral line, and θ is the phase difference between V2 and V3.

[0042] In a possible design, the voltage between the third phase line and the neutral line conforms to the following formula:

[0043]

[0044] Wherein, V4 is the voltage between the third phase line and the neutral line, V5 is the voltage between the first phase line and the neutral line, V6 is the voltage between the first phase line and the third phase line, and σ is the phase difference between V5 and V6.

[0045] In one possible design, when the processing module determines the voltage between each phase line and the neutral point based on the voltage between each two phase lines, it is specifically used to: construct a target triangle model in a set coordinate system based on the voltage between each two phase lines, wherein the three side lengths of the target triangle model are the voltage between each two phase lines; determine the target point corresponding to the target triangle model in the set coordinate system, wherein the target point and the line connecting any two endpoints of the target triangle model can form an angle of 120° after intersecting; determine the distance from the target point to each endpoint in the target triangle model; and use the distance from the target point to each endpoint as the voltage value between each phase line and the neutral point.

[0046] In a possible design, if the three internal angles of the target triangular model are all less than 120°, the target point is a Fermat point of the target triangular model; or the target point is an isometric center point of the target triangular model.

[0047] In a possible design, the three side lengths of the target triangle model are the first side length, the second side length and the third side length; when the processing module determines the target point corresponding to the target triangle model in the set coordinate system, it is specifically used to: construct a first target circle model corresponding to the first side length and a second target circle model corresponding to the second side length in the set coordinate system, wherein the first target circle model includes the two endpoints of the first side length and the target point, and the second target circle model includes the two endpoints of the second side length and the target point; determine the coordinates of the center of the first target circle model according to the coordinates of the two endpoints of the first side length; and determine the coordinates of the center of the second target circle model according to the coordinates of the two endpoints of the second side length; determine the coordinates of the target point according to the coordinates of the center of the first target circle model and the coordinates of the center of the second target circle model.

[0048] In a possible design, the coordinate origin of the set coordinate system is any endpoint of the target triangle model, and a coordinate axis in the set coordinate system coincides with a side length of the target triangle model at the coordinate origin.

[0049] In one possible design, when the processing module determines the voltage between the neutral line and the neutral point based on the voltage between each phase line and the neutral line, and the voltage between each phase line and the neutral point, it is specifically used to: determine the target difference corresponding to each phase line, wherein the target difference corresponding to the target phase line is the difference between: the voltage between the target phase line and the neutral line, and the voltage between the target phase line and the neutral point; and take the maximum value of the target differences corresponding to the three phase lines as the voltage between the neutral line and the neutral point.

[0050] In one possible design, when the processing module determines whether the neutral line has a broken line fault based on the voltage between the neutral line and the neutral point, it is specifically used to: determine whether the voltage between the neutral line and the neutral point is greater than a set threshold; if it is determined that the voltage between the neutral line and the neutral point is greater than the set threshold, it is determined that the neutral line has a broken line fault; otherwise, it is determined that the neutral line has not a broken line fault.

[0051] In a third aspect, the present application provides a fault detection device for a three-phase power distribution system, wherein the three-phase power distribution system includes three phase lines and a neutral line; wherein the three phase lines intersect the neutral line at a neutral point, and the three phase lines include: a first phase line, a second phase line, and a third phase line; and at least one of the three phase lines is connected to the neutral line;

[0052] The fault detection device includes a transceiver and at least one processor; the transceiver is used to obtain the voltage between each two phase lines; the processor is used to determine the voltage between each phase line and the neutral point based on the voltage between each two phase lines; determine the voltage between the neutral line and the neutral point based on the voltage between each phase line and the neutral line, and the voltage between each phase line and the neutral point; and determine whether a neutral line break fault occurs based on the voltage between the neutral line and the neutral point.

[0053] In a possible design, any phase line connected to the neutral line is connected to the neutral line through a resistance element.

[0054] In one possible design, when the transceiver obtains the voltage between each two phase lines, it is specifically used to: obtain the voltage between each phase line and the neutral line; and determine the voltage between each two phase lines based on the voltage between each phase line and the center line.

[0055] In a possible design, when the transceiver obtains the voltage between each two phase lines, it is specifically used to: obtain the voltage between the first phase line and the neutral line, the voltage between the second phase line and the neutral line, and the voltage between the first phase line and the third phase line; determine the voltage between the first phase line and the second phase line based on the voltage between the first phase line and the neutral line and the voltage between the second phase line and the neutral line; determine the voltage between the third phase line and the neutral line based on the voltage between the first phase line and the neutral line and the voltage between the first phase line and the third phase line; determine the voltage between the second phase line and the third phase line based on the voltage between the second phase line and the neutral line and the voltage between the third phase line and the neutral line.

[0056] In one possible design, the voltage between the first phase line and the second phase line satisfies the following formula:

[0057]

[0058] Wherein, V1 is the voltage between the first phase line and the second phase line, V2 is the voltage between the first phase line and the neutral line, V3 is the voltage between the second phase line and the neutral line, and θ is the phase difference between V2 and V3.

[0059] In a possible design, the voltage between the third phase line and the neutral line conforms to the following formula:

[0060]

[0061] Wherein, V4 is the voltage between the third phase line and the neutral line, V5 is the voltage between the first phase line and the neutral line, V6 is the voltage between the first phase line and the third phase line, and σ is the phase difference between V5 and V6.

[0062] In one possible design, when the processor determines the voltage between each phase line and the neutral point based on the voltage between each two phase lines, it is specifically used to: construct a target triangle model in a set coordinate system based on the voltage between each two phase lines, wherein the three side lengths of the target triangle model are the voltage between each two phase lines; determine the target point corresponding to the target triangle model in the set coordinate system, wherein the target point and the line connecting any two endpoints of the target triangle model can form an angle of 120° after intersecting; determine the distance from the target point to each endpoint in the target triangle model; and use the distance from the target point to each endpoint as the voltage value between each phase line and the neutral point.

[0063] In a possible design, if the three internal angles of the target triangular model are all less than 120°, the target point is a Fermat point of the target triangular model; or the target point is an isometric center point of the target triangular model.

[0064] In one possible design, the three side lengths of the target triangle model are the first side length, the second side length and the third side length; when the processor determines the target point corresponding to the target triangle model in the set coordinate system, it is specifically used to: construct a first target circle model corresponding to the first side length and a second target circle model corresponding to the second side length in the set coordinate system, wherein the first target circle model includes the two endpoints of the first side length and the target point, and the second target circle model includes the two endpoints of the second side length and the target point; determine the coordinates of the center of the first target circle model according to the coordinates of the two endpoints of the first side length; and determine the coordinates of the center of the second target circle model according to the coordinates of the two endpoints of the second side length; determine the coordinates of the target point according to the coordinates of the center of the first target circle model and the coordinates of the center of the second target circle model.

[0065] In a possible design, the coordinate origin of the set coordinate system is any endpoint of the target triangle model, and a coordinate axis in the set coordinate system coincides with a side length of the target triangle model at the coordinate origin.

[0066] In one possible design, when the processor determines the voltage between the neutral line and the neutral point based on the voltage between each phase line and the neutral line, and the voltage between each phase line and the neutral point, it is specifically used to: determine the target difference corresponding to each phase line, wherein the target difference corresponding to the target phase line is the difference between: the voltage between the target phase line and the neutral line, and the voltage between the target phase line and the neutral point; and take the maximum value of the target differences corresponding to the three phase lines as the voltage between the neutral line and the neutral point.

[0067] In one possible design, when the processor determines whether a disconnection fault occurs in the neutral line based on the voltage between the neutral line and the neutral point, it is specifically used to: determine whether the voltage between the neutral line and the neutral point is greater than a set threshold; if it is determined that the voltage between the neutral line and the neutral point is greater than the set threshold, it is determined that a disconnection fault occurs in the neutral line; otherwise, it is determined that no disconnection fault occurs in the neutral line.

[0068] In one possible design, the fault detection device further includes a memory, wherein the memory is used to store computer program code, wherein the computer program code includes computer instructions, and the computer program code is used to be provided to the processor for execution.

[0069] In a fourth aspect, an embodiment of the present application provides a computer-readable storage medium, which stores computer program instructions. When the computer program instructions are run on a fault detection device, the fault detection device executes the method described in the first aspect or any possible design of the first aspect.

[0070] In a fifth aspect, an embodiment of the present application provides a computer program product, which, when run on a fault detection device, enables the fault detection device to execute the method described in the first aspect or any possible design of the first aspect.

[0071] In a sixth aspect, an embodiment of the present application provides a chip, which is used to read a computer program stored in a memory and execute the method described in the above-mentioned first aspect or any possible design of the first aspect.

[0072] For the beneficial effects of the second to sixth aspects mentioned above, please refer to the description of the beneficial effects of the first aspect mentioned above, and will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0073] Figure 1a This is a circuit diagram of a three-phase four-wire power distribution system;

[0074] Figure 1bThis is a circuit diagram of a three-phase five-wire power distribution system;

[0075] Figure 2a A circuit diagram of a three-phase power distribution system provided in an embodiment of the present application;

[0076] Figure 2b A circuit diagram of another three-phase power distribution system provided in an embodiment of the present application;

[0077] Figure 3 A schematic diagram of a fault detection method for a three-phase power distribution system provided in an embodiment of the present application;

[0078] Figure 4 A schematic diagram of voltage vectors in a three-phase power distribution system provided in an embodiment of the present application;

[0079] Figure 5 A schematic diagram of a target triangle model and a target circle model provided in an embodiment of the present application;

[0080] Figure 6 A schematic diagram of a target triangle model and a target circle model provided in an embodiment of the present application;

[0081] Figure 7 A schematic diagram of a fault detection device provided in an embodiment of the present application;

[0082] Figure 8 A schematic structural diagram of a fault detection device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0083] To make the objectives, technical solutions, and advantages of the embodiments of the present application more clear, the embodiments of the present application will be further described in detail below with reference to the accompanying drawings. In the description of the embodiments of the present application, the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of technical features indicated. Therefore, features defined as "first" or "second" may explicitly or implicitly include one or more of such features.

[0084] It should be understood that in the embodiments of the present application, "at least one" refers to one or more, and "more" refers to two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone, where A and B can be singular or plural. The character " / " generally indicates that the previous and next associated objects are in an "or" relationship. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single or plural items. For example, at least one of a, b or c can represent: a, b, c, a and b, a and c, b and c, or a, b and c, where a, b, c can be single or multiple.

[0085] To facilitate understanding, exemplary descriptions of concepts related to this application are provided for reference.

[0086] 1) A three-phase power distribution system is a power distribution system that uses a three-phase circuit, such as a three-phase four-wire or three-phase five-wire distribution system. A three-phase circuit is powered by a three-phase AC power source, which can provide three voltages or electromotive forces with the same frequency, equal amplitude, and 120° phase difference to the three transmission lines (three phases) in the three-phase circuit. The three-phase AC power source can be a generator or a transformer.

[0087] In the embodiment of the present application, the three-phase power distribution system can be, but is not limited to, a three-phase four-wire system and a three-phase five-wire system.

[0088] A three-phase, four-wire system refers to a three-phase power distribution system consisting of three phase lines plus a neutral line (working neutral). In this system (hereinafter referred to as the three-phase, four-wire system), one end of the three phase lines intersects at the neutral point, and the other end is connected to the load. The neutral line is connected to the load at one end, extending from the neutral point. The three phase lines transmit power, while the neutral line and the three phase lines form a working circuit, maintaining voltage balance among the three phase lines. This means that the phase difference between any two of the three phase lines is 120°. In a three-phase, four-wire system, when the three phases are balanced, no current flows in the neutral line.

[0089] A three-phase, five-wire system refers to a three-phase power distribution system consisting of three phase wires, a neutral wire, and a protective neutral wire. This system is based on a three-phase, four-wire system but adds a protective ground wire to prevent the neutral wire from becoming energized.

[0090] 2) Neutral Point: Also known as the zero point, the neutral point is the common point in a three-phase power distribution system connected in a star configuration. Depending on the operating mode, it can operate in either grounded or ungrounded modes. A neutral wire can be drawn from the neutral point and then grounded through it.

[0091] 3) Load: In physics, load refers to the electronic components, devices or equipment connected to both ends of the power supply in the circuit, which is used to convert electrical energy into other forms of energy. It is also called an electrical appliance.

[0092] Figure 1a This is a circuit diagram of a three-phase four-wire power distribution system. Figure 1a As shown in the figure, lines A, B, and C are the three phase lines in the power distribution system, line O is the neutral line, and point N is the neutral point. The transformer can act as a voltage source to provide three-phase AC power. One end of the three phase lines intersects at the neutral point after passing through the transformer. One end of the neutral line also connects to the neutral point. The other ends of the three phase lines and the other end of the neutral line can be connected to a load (not shown in the figure).

[0093] Figure 1b This is a circuit diagram of a three-phase five-wire power distribution system. Figure 1a A protection line, namely PE line, is added to the circuit of the three-phase four-wire power distribution system shown in the figure, and the result is as follows Figure 1b The three-phase, five-wire power distribution system shown in the figure. In a three-phase, five-wire power distribution system, the PE line is used to ensure circuit safety. One end of the PE line is connected to the neutral point, and the other end can be connected to the load (not shown in the figure).

[0094] In the above Figure 1a The circuit of the three-phase four-wire power distribution system shown in Figure 1b In the circuit of the three-phase five-wire power distribution system shown in the figure, if a neutral line fault occurs (for example Figure 1b When a neutral line fault occurs (as shown in the dashed box), it can significantly impact the normal operation and performance of the circuit. Currently, detecting whether a neutral line fault has occurred in the power distribution system circuit is typically done using a three-phase voltage common-mode component solution. Specifically, a neutral line fault can be determined by detecting whether the three-phase zero-sequence voltage or the voltage between the neutral point and the PE line (neutral-to-PE voltage) is greater than a preset threshold.

[0095] The three-phase zero-sequence voltage is calculated according to the following formula:

[0096] v ON =(v AO +v BO +v CO ) / 3

[0097] Among them, v ON is the three-phase zero-sequence voltage, v AO is the voltage measured between line A and the neutral line, v BO is the voltage measured between line B and neutral line, v COis the voltage measured between the C line and the neutral line.

[0098] The aforementioned disconnection fault detection method has poor grid adaptability and can cause false detection in some scenarios. For example, when the three-phase voltage is unbalanced or contains odd-order harmonics, the detected zero-sequence voltage can be greater than the actual zero-sequence voltage, causing false alarms and malfunctioning electrical equipment. For another example, when the PE line is not connected to the circuit, detecting the voltage between the neutral and PE lines can also cause false alarms and malfunction electrical equipment.

[0099] In view of this, an embodiment of the present application provides a fault detection method for a three-phase power distribution system, so as to improve the accuracy of detecting a neutral line break fault.

[0100] The following first introduces the three-phase power distribution system provided in the embodiment of the present application.

[0101] In an embodiment of the present application, a three-phase power distribution system, such as a three-phase four-wire power distribution system or a three-phase five-wire power distribution system, includes at least three phase lines and a neutral line, wherein the three phase lines intersect with the neutral line at a neutral point, and the three phase lines include: a first phase line, a second phase line, and a third phase line; and at least one of the three phase lines is connected to the neutral line, so that when a line break fault occurs in the neutral line, the phase difference of the voltage between two of the three phase lines is not 120°.

[0102] In some embodiments of the present application, any phase line connected to the neutral line is connected to the neutral line through a resistance element.

[0103] In some embodiments of the present application, at least one phase line is connected to the neutral line via a resistor element. Among all phase lines connected to the neutral line, at most two phase lines are connected to the neutral line via resistor elements of the same resistance value.

[0104] Optionally, the three-phase power distribution system can be obtained by connecting at least one of the three phase lines and the neutral line through a resistance element on the basis of an existing three-phase circuit.

[0105] The three-phase power distribution system is exemplarily described below with reference to specific examples.

[0106] Example 1

[0107] Figure 2a This is a circuit diagram of a three-phase power distribution system provided in an embodiment of the present application. Figure 2aAs shown, the power distribution system can adopt a three-phase five-wire distribution system. In this three-phase five-wire distribution system, the first, second, and third phases are A, B, and C, respectively. One end of each of A, B, and C intersects at the neutral point after passing through a transformer, and the other end can be connected to an inverter. One end of the neutral line is connected to the neutral point (point N), and the other end can be connected to the inverter. The dashed box in the figure indicates a break in the neutral line. When the neutral line is not faulty, the lines O and N are connected. The neutral point is grounded. One end of the PE line is grounded (and connected to the neutral point), and the other end can be connected to the inverter. In this three-phase five-wire distribution system, each of A, B, and C is connected to the neutral line via a resistor element, ensuring that the phase difference between any two phases of A, B, and C is not 120° in the event of a neutral line break.

[0108] The resistance element may be a variable resistor or a resistor with a fixed resistance.

[0109] For example, Figure 2a As shown in , line A is connected to the neutral line through a variable resistor R1, line B is connected to the neutral line through a variable resistor R2, and line C is connected to the neutral line through a variable resistor R3. The resistance values ​​of resistors R1, R2, and R3 can be any of the following:

[0110] 1) R1=R2≠R3, that is, the resistance between line A, line B and the neutral line is the same, and different from the resistance between line C and the neutral line.

[0111] 2) R1≠R2=R3, that is, the resistance between line B, line C and the neutral line is the same, and different from the resistance between line A and the neutral line.

[0112] 3) R1=R3≠R2, that is, the resistance between line A, line C and the neutral line is the same, and different from the resistance between line B and the neutral line.

[0113] 4) R1≠R2≠R3, that is, the resistances between line A, line B, line C and the neutral line are different.

[0114] Example 2

[0115] Figure 2b This is a circuit diagram of another three-phase power distribution system provided in an embodiment of the present application. Figure 2bAs shown, the power distribution system can adopt a three-phase five-wire distribution system. In this three-phase five-wire distribution system, the first, second, and third phases are Line A, Line B, and Line C, respectively. Lines A, B, and C intersect at the neutral point after passing through a transformer, and their other ends can be connected to an inverter. The neutral line has one end connected to the neutral point, and its other end can be connected to the inverter. The neutral point is grounded. The PE line has one end connected to the ground (and connected to the neutral point), and its other end can be connected to the inverter. Any two of the three phase lines (A, B, and C) are connected to the neutral line via resistors. This ensures that the voltage phase difference between any two of the three phase lines (A, B, and C) is not 120° in the event of a neutral line fault.

[0116] For example, the arbitrary two phase lines may be line A and line B, such as Figure 2b As shown, line A is connected to the neutral line via a variable resistor R4, and line B is connected to the neutral line via a variable resistor R5. The resistances of R4 and R5 can be the same or different, meaning that the resistances between line A, line B, and the neutral line can be the same or different.

[0117] For another example, the arbitrary two phase lines may be line A and line C, or may be line B and line C, and the resistance between the arbitrary two phase lines and the neutral line may be the same or different.

[0118] Example 3

[0119] In a three-phase power distribution system, only any one of the three phase lines can be connected to the neutral line through a resistor element, which can also ensure that when a neutral line fault occurs, the phase difference between the voltages of any two of the three phase lines (A, B, and C) is not 120°.

[0120] For example, as mentioned above Figure 2a In the three-phase five-wire power distribution system shown in FIG, only the variable resistor between any one of the three phase lines and the neutral line can be retained, and the variable resistors between the other two phase lines and the neutral line can be removed. Figure 2b In the three-phase five-wire power distribution system shown, only the variable resistor between any one phase line and the neutral line may be retained, and the variable resistor between the other phase line and the neutral line may be removed.

[0121] It should be noted that the above Figure 2a or Figure 2b The three-phase five-wire power distribution system is used as an example for illustration, but does not limit the circuit composition of the three-phase power distribution system to which the method provided in this application is applicable. The three-phase power distribution system in this application can also be a three-phase four-wire power distribution system or other three-phase power distribution system that adopts the above-mentioned wiring method between the phase line and the neutral line.

[0122] above Figure 2a or Figure 2b The inverter shown can also be an electrical device such as a rectifier or a load. Figure 2a or Figure 2b Some electrical equipment may also be added or removed from the power distribution system shown.

[0123] In the above embodiments of the present application, the resistance of the resistor connected between the phase line and the neutral line can take a relatively large resistance value, for example, a resistance value greater than a set threshold value, to reduce the power consumed by the resistor, thereby minimizing the impact on the three-phase circuit while shifting the phase angle of the voltage on the three phase lines.

[0124] In the above embodiment, a three-phase unbalanced circuit is formed by connecting some or all of the phase lines to the neutral line on the side of the AC port of the electrical equipment connected to the three-phase power distribution system. That is, in the three-phase power distribution system, when a neutral line fault occurs, the phase difference of the voltage between the three phase lines and the neutral line is not all 120°. This circuit can ensure that the phase difference of the voltage between at least two of the three phase lines is not 120°, and in the event of a neutral line fault, the deviation of the voltage of the three phase lines relative to the reference ground (point O) and the voltage of the three phase lines relative to the true neutral line can be increased.

[0125] The following is a detailed introduction to the fault detection method of the three-phase power distribution system provided in the embodiment of the present application.

[0126] It should be noted that the fault detection method provided in the embodiment of the present application can be executed based on the three-phase power distribution system provided in the above embodiment.

[0127] The following description will take a fault detection device as an example of an execution entity of the fault detection method, wherein the fault detection device can be any entity with data processing capabilities, such as a computer, a server, a terminal device, etc.

[0128] Figure 3 A schematic diagram of a fault detection method for a three-phase power distribution system provided in an embodiment of the present application. The three-phase power distribution system includes three phase lines and a neutral line; wherein the three phase lines intersect with the neutral line at a neutral point, and the three phase lines include: a first phase line, a second phase line, and a third phase line; at least one of the three phase lines is connected to the neutral line, so that when a neutral line fault occurs, the phase difference between the voltages of two of the three phase lines is not 120°. Figure 3 As shown, the method includes:

[0129] S301: The fault detection device obtains the voltage between every two phase lines.

[0130] The fault detection device first obtains the voltage between every two phase lines of the three-phase power distribution system, which can be done in any of the following ways:

[0131] Method 1

[0132] The fault detection device obtains the voltage between each two phase lines by sampling. Specifically, the fault detection device can measure the voltage between each two phase lines respectively through a set voltage measurement circuit, or the fault detection device can receive the voltage between each two phase lines input by a user.

[0133] Method 2

[0134] The fault detection device may first obtain the voltage between each phase line and the neutral line, and then determine the voltage between each pair of phase lines based on the voltage between each phase line and the neutral line. The voltage between each phase line and the neutral line is obtained through sampling. Specifically, the fault detection device may measure the voltage between each phase line and the neutral line using a predetermined voltage measurement circuit, or the fault detection device may receive user input of the voltage between each phase line and the neutral line.

[0135] Method 3

[0136] The fault detection device may first obtain the voltage between the first phase line and the neutral line, the voltage between the second phase line and the neutral line, and the voltage between the first phase line and the third phase line, and then determine the voltage between every two phase lines based on the three voltages obtained. Specifically, the fault detection device may first determine the voltage between the first phase line and the second phase line based on the voltage between the first phase line and the neutral line and the voltage between the second phase line and the neutral line; and determine the voltage between the third phase line and the neutral line based on the voltage between the first phase line and the neutral line and the voltage between the first phase line and the third phase line; and then determine the voltage between the second phase line and the third phase line based on the voltage between the second phase line and the neutral line and the voltage between the third phase line and the neutral line, and finally obtain the voltage between every two phase lines.

[0137] Among them, the method for obtaining the voltage between the first phase line and the neutral line, the voltage between the second phase line and the neutral line, and the voltage between the first phase line and the third phase line can refer to the above-mentioned method for obtaining the voltage between every two phase lines or the method for obtaining the voltage between each phase line and the neutral line, which will not be repeated here.

[0138] For example, in the above Figure 2a or Figure 2bIn the circuit of the three-phase power distribution system shown in the figure, the voltage vector corresponding to the voltage between each phase line and the neutral line is as follows Figure 4 shown.

[0139] Figure 4 This is a voltage vector diagram of a three-phase power distribution system provided in an embodiment of the present application. Figure 4 As shown in the figure, vector OA represents the voltage V between line A and neutral line. AO , vector OB represents the voltage V between line B and neutral line BO 、 Vector OC represents the voltage V between line C and neutral line CO Vector AB represents the voltage V between line A and line B. AB , vector AC represents the voltage V between line A and line C AC , vector BC represents the voltage V between line B and line C BC .

[0140] The angle between vector OA and vector OB represents V AO With V BO The phase difference between them, the angle between vector OA and vector OC represents V AO With V CO The phase difference between them, the angle between vector OB and vector OC represents V BO With V CO The phase difference between them. The angle between vector AB and vector AC represents V AB With V BC The phase difference between them, the angle between vector AB and vector BC represents V AB With V BC The phase difference between them, the angle between vector AC and vector BC represents V AC With V BC The phase difference between them.

[0141] In some embodiments of the present application, the voltage between the first phase line and the second phase line conforms to the following formula:

[0142]

[0143] Wherein, V1 is the voltage between the first phase line and the second phase line, V2 is the voltage between the first phase line and the neutral line, V3 is the voltage between the second phase line and the neutral line, and θ is the phase difference between V2 and V3.

[0144] The formulas that the voltage between the first phase line and the third phase line and the voltage between the second phase line and the third phase line conform to can refer to the formula that the voltage between the first phase line and the second phase line conforms to, and are not repeated here.

[0145] In the above-mentioned method 2, the fault detection device can determine the voltage between every two phase lines according to the above-mentioned formula; in the above-mentioned method 3, the fault detection device can also determine the voltage between the first phase line and the second phase line, and the voltage between the second phase line and the third phase line according to the above-mentioned formula.

[0146] For example, in the above method 2, if Figure 4 As shown in FIG, the fault detection device obtains the voltage V AO 、V BO 、V CO After that, we can use the above formula to calculate the value of V AO 、V BO and V AO and V BO The voltage V between line A and line B is calculated by the phase angle between them. AB According to V AO 、V CO and V AO and V CO The voltage V between line A and line C is calculated by the phase angle between them. AC According to V BO 、V CO and V BO and V CO The voltage V between line B and line C is calculated by the phase angle between them. BC .

[0147] In some embodiments of the present application, the voltage between the third phase line and the neutral line conforms to the following formula:

[0148]

[0149] Wherein, V4 is the voltage between the third phase line and the neutral line, V5 is the voltage between the first phase line and the neutral line, V6 is the voltage between the first phase line and the third phase line, and σ is the phase difference between V5 and V6.

[0150] In the above-mentioned method three, the fault detection device can determine the voltage between the third phase line and the neutral line according to the formula, so as to determine the voltage between the second phase line and the third phase line according to the voltage between the third phase line and the neutral line, and the voltage between the second phase line and the neutral line.

[0151] S302: The fault detection device determines the voltage between each phase line and the neutral point according to the voltage between every two phase lines.

[0152] After determining the voltage between every two phase lines of the three phase lines, the fault detection device constructs a target triangle model in a set coordinate system according to the voltage between every two phase lines, wherein the three side lengths of the target triangle model are the voltage between every two phase lines.

[0153] As an optional implementation, the set coordinate system may be any coordinate system in which the target triangular model is established. As another optional implementation, the coordinate origin of the set coordinate system is any endpoint of the target triangular model, and a coordinate axis in the set coordinate system coincides with a side length of the target triangular model at the coordinate origin.

[0154] For example, the target triangle model can be Figure 4 The triangle model ABC shown in .

[0155] After constructing the target triangle model, the fault detection device determines a target point corresponding to the target triangle model in the set coordinate system, wherein the target point forms an angle of 120° when intersected with a line connecting any two endpoints of the target triangle model. In the three-phase power distribution system, when the voltages on the three phase lines are balanced, the phase difference between the voltages of any two phase lines relative to the neutral point is 120°. Therefore, the target point corresponding to the target triangle model corresponds to the neutral point of the three-phase power distribution system.

[0156] For example, Figure 4 As shown in , the target point corresponding to the target triangle model ABC can be marked as point N, wherein the line between point N and points A, B, and C divides the circumference angle where point N is located equally, and angles ANB, ANC, and BNC are all 120°.

[0157] In some embodiments of the present application, if the three internal angles of the target triangular model are all less than 120°, the target point is the Fermat point of the target triangular model; or, the target point is the isometric center point of the target triangular model.

[0158] Among them, the Fermat point refers to a point located in a triangle and having the shortest sum of distances to the three vertices of the triangle. If the three internal angles of the triangle are all less than 120°, the line connecting the distances between the Fermat point and the three vertices just divides the circumference angle where the Fermat point is located into three equal parts, that is, the three angles of the three sides of the triangle opposite to the Fermat point are equal, all of which are 120°. Therefore, when the three internal angles of the target triangle model are all less than 120°, the method of calculating the Fermat point of the target triangle model can be used to determine the N points. The line connecting the distances between the isotropic center point and the three vertices also just divides the circumference angle where the isotropic center point is located into three equal parts, that is, the three angles of the three sides of the triangle opposite to the isotropic center point are equal, all of which are 120°. Therefore, in the embodiment of the present application, the method of calculating the isotropic center point of the target triangle model can also be used to determine the N points.

[0159] In some embodiments of the present application, the three side lengths of the target triangle model are the first side length, the second side length and the third side length, respectively. When determining the target point corresponding to the target triangle model, a first target circle model corresponding to the first side length and a second target circle model corresponding to the second side length can be first constructed in the set coordinate system, wherein the first target circle model includes the two endpoints of the first side length and the target point, and the second target circle model includes the two endpoints of the second side length and the target point; then, according to the coordinates of the two endpoints of the first side length, the coordinates of the center of the first target circle model are determined; and according to the coordinates of the two endpoints of the second side length, the coordinates of the center of the second target circle model are determined; finally, according to the coordinates of the center of the first target circle model and the coordinates of the center of the second target circle model, the coordinates of the target point are determined.

[0160] After determining the coordinates of the target point, the fault detection device determines the distance from the target point to each endpoint in the target triangular model, and uses the distance from the target point to each endpoint as the voltage value between each phase line and the neutral point. The fault detection device may calculate the distance from the target point to each endpoint based on the coordinates of the target point and the coordinates of each endpoint in the target triangular model using a Euclidean distance calculation formula.

[0161] For example, Figure 4 As shown in , in the target triangle model ABC, the distances from point N to each endpoint are AN, BN, and CN, respectively, corresponding to the voltage between each phase line and the neutral point.

[0162] S303: The fault detection device determines the voltage between the neutral line and the neutral point according to the voltage between each phase line and the neutral line and the voltage between each phase line and the neutral point.

[0163] After the above-mentioned fault detection device determines the voltage between each phase line and the neutral point, it first determines the target difference corresponding to each phase line based on the voltage between each phase line and the neutral line, and the voltage between each phase line and the neutral point, wherein the target difference corresponding to the target phase line is the difference between the following two: the voltage between the target phase line and the neutral line, and the voltage between the target phase line and the neutral point; and then the maximum value of the target differences corresponding to the three phase lines is used as the voltage between the neutral line and the neutral point.

[0164] S304: The fault detection device determines whether a disconnection fault occurs in the neutral line according to the voltage between the neutral line and the neutral point.

[0165] After the fault detection device determines the voltage between the neutral line and the neutral point, it determines whether the voltage between the neutral line and the neutral point is greater than a set threshold; if it is determined that the voltage between the neutral line and the neutral point is greater than the set threshold, it is determined that a neutral line break fault has occurred; otherwise, it is determined that no neutral line break fault has occurred.

[0166] In some embodiments of the present application, after the fault detection device determines that a neutral line break fault occurs, it can output a prompt message indicating that a neutral line break fault occurs.

[0167] In the above embodiment, a three-phase unbalanced circuit is formed to increase the deviation between the voltage on the three phase lines relative to the neutral line voltage and the voltage on the three phase lines relative to the true neutral line voltage in a three-phase power distribution system. A target triangle model is then established based on the sampled voltages between the three phase lines and the neutral line. A target point corresponding to the exact neutral point is determined based on plane geometry principles. The distance between the target point and each endpoint of the target triangle model is then determined as the voltage between each phase line and the target point. Finally, the voltage between the neutral line and the neutral point is determined by comparing the calculated three-phase-to-neutral voltage difference with the sampled three-phase-to-reference ground (neutral) voltage difference, and fault detection is performed. This method directly determines whether a neutral line fault has occurred based on the voltage between the neutral point and the neutral line. It can accurately detect the three-phase-to-true neutral line voltage and thus determine whether a neutral line fault has occurred in scenarios such as a disconnected PE line, an unbalanced three-phase power grid, and the presence of harmonics. Therefore, this method has good grid adaptability, reduces false detection issues, and improves detection accuracy. Furthermore, in this method, different voltage data in the three-phase power distribution system are mapped into a mathematical model, and mathematical calculations are used instead of some sampling measurements, which can further reduce the errors caused by sampling measurements and improve the accuracy of fault detection.

[0168] The method for determining the target point corresponding to the target triangle model in step S302 is described in detail below.

[0169] Figure 5 A schematic diagram of a target triangle model and a target circle model provided in an embodiment of the present application.

[0170] For example, Figure 5 As shown in , assuming that in the target triangle model ABC, the first side length is AB and the second side length is BC. Assume that the circle with point O1 as the center and r1 as the radius is the first target circle model, and the circle with point O2 as the center and r2 as the radius is the second target circle model.

[0171] The terminal device may determine the coordinates of the target point N by using either the following method 1 or method 2.

[0172] Method 1

[0173] In this manner, the set coordinate system may be any coordinate system where the target triangle model is established.

[0174] like Figure 5 As shown, in the first target circle model, triangles AO1N, BO1N, and O1BA are all isosceles triangles. Therefore, it can be determined that the sum of the angles O1AN and O1BN is equal to the angle ANB, which is 120° (i.e., ∠O1AN+∠O1BN=∠ANB=120°). Furthermore, it can be determined that the angle AO1B is also 120°, and the angle O1BA is 30°. The relationship between the radius r1 and the length AB satisfies the following formula:

[0175]

[0176] Among them, V AB is the length of side AB, which represents the voltage between line A and line B in a three-phase power distribution system.

[0177] The V AB It also satisfies the following formula:

[0178]

[0179] Among them, x 11 、y 11 and x 12 、y 12 They are the coordinates of the endpoint A and the endpoint B of the first side length AB respectively.

[0180] Similarly, in the second target circle model, the relationship between the radius r2 and the BC length satisfies the following formula:

[0181]

[0182] Among them, V BCis the length of the BC side, which represents the voltage between lines B and C in a three-phase distribution system.

[0183] The V BC It also satisfies the following formula:

[0184]

[0185] Among them, x 12 、y 12 and x 13 、y 13 They are respectively the coordinates of the endpoints B and C of the first side length BC.

[0186] Based on the Euclidean distance formula, the length of AB can be determined according to the coordinates of points A and B, and then the size of r1 can be determined. At the same time, the size of r1 can also be determined according to the coordinates of point O1 and point A or according to the coordinates of point O1 and point B. Therefore, the following set of equations can be obtained:

[0187]

[0188] Among them, x1 and y1 are the coordinates of the center point O1 of the first target circle model, x 11 、y 11 and x 12 、y 12 are the coordinates of the endpoints A and B of the first side AB, V AB is the length of the first side AB.

[0189] The coordinates of point O1 can be obtained by solving the above equations.

[0190] Similarly, the coordinates of the center point O2 of the second target circle model can be obtained by referring to the above method.

[0191] After the fault detection device determines the coordinates of the center point O1 of the first target circle model and the center point O2 of the second target circle model respectively by the above method, the following set of equations can be obtained:

[0192]

[0193] Among them, x and y are the coordinates of the target point, x1 and y1 are the coordinates of the center point O1, x2 and y2 are the coordinates of the center point O2, V AB is the length of the first side AB, V BC is the length of the first side BC.

[0194] The coordinates of the target point can be obtained by solving the above equations.

[0195] In this method, after establishing the set coordinate system where the target triangle model is located, the coordinates of each endpoint of the target triangle in the set coordinate system can be determined. Combined with the planar geometric features of the target triangle model and the established target circle model, the coordinates of the center of the target circle model can be calculated based on the coordinates of each endpoint of the target triangle model, and then the coordinates of the target point can be calculated based on the coordinates of the relevant feature points.

[0196] Method 2

[0197] In this method, the coordinate origin of the set coordinate system can be any endpoint of the target triangle model, one coordinate axis of the set coordinate system coincides with any side length where the coordinate origin is located, and the other coordinate axis is perpendicular to the side length.

[0198] Figure 6 A schematic diagram of a target triangle model and a target circle model provided in an embodiment of the present application.

[0199] For example, in this manner, the fault detection device may be Figure 5 In the target triangle model shown in , the endpoint B of triangle ABC is selected as the origin of the set coordinate system, the second side length BC is selected as the horizontal axis (X axis) of the set coordinate system, and the straight line perpendicular to the second side length BC and passing through point B is used as the vertical axis (Y axis) of the set coordinate system, and the following is obtained: Figure 6 The XBY coordinate system shown.

[0200] like Figure 6 As shown in , the angle AO1B is 120° and the angle O1BA is 30°, then the relationship between the radius r1 and the length AB satisfies the following formula:

[0201]

[0202] Among them, V AB is the length of side AB, which represents the voltage between line A and line B in a three-phase power distribution system.

[0203] According to the sine and cosine theorems of a triangle, we can get the coordinates of point O1 and point O2.

[0204] The coordinates of point O1 are:

[0205]

[0206] Among them, x1 and y1 are the coordinates of point O1, V BC is the length of the BC side, which represents the voltage between lines B and C in a three-phase distribution system.

[0207] The coordinates of point O2 are:

[0208]

[0209] in, x2, y2 are the coordinates of point O2, V AB is the length of side AB and represents the voltage between line A and line B in a three-phase power distribution system, V BC is the length of the BC side and represents the voltage between the B and C lines in the three-phase distribution system, V CA is the length of the CA side and represents the voltage between line C and line A in the three-phase distribution system. For angle ABC, V AB With V BC The phase difference between them.

[0210] The fault detection device obtains the coordinates of point O1 and point O2, and the following equations can be obtained based on the circumferential distance formula:

[0211]

[0212] Among them, x and y are the coordinates of the target point, x1 and y1 are the coordinates of point O1, and x2 and y2 are the coordinates of point O2.

[0213] Solving this system of equations yields:

[0214]

[0215] Among them, x and y are the coordinates of the target point, x1 and y1 are the coordinates of point O1, and x2 and y2 are the coordinates of point O2.

[0216] Then the distance from the target point to each endpoint can be obtained as follows:

[0217]

[0218] Among them, V AN is the length of line segment AN and represents the voltage between line A and the neutral point in the three-phase distribution system, V BN is the length of line segment BN and represents the voltage between line B and the neutral point in the three-phase distribution system, V CN is the length of the line segment CN, and represents the voltage between line C and the neutral point in the three-phase power distribution system. x and y are the coordinates of the target point. is angle ABC, represents V AB With V BC The phase difference between them.

[0219] In this method, by setting the set coordinate system in a specific manner so that some reference points (such as the center point of the target circle model) fall on a right triangle with a specific angle, the coordinates of the reference point can be determined directly based on the side length, angle and geometric distribution characteristics of the right triangle, avoiding a large number of related coordinate calculations. Therefore, the calculation steps can be simplified, the amount of data calculation can be reduced, and the coordinates of the target point can be determined more quickly and easily.

[0220] In the embodiments provided in the present application above, the fault detection method for the three-phase power distribution system provided in the embodiments of the present application is introduced from the perspective of the fault detection device as the execution subject. In order to realize the various functions in the fault detection method for the three-phase power distribution system provided in the embodiments of the present application above, the fault detection device may include a hardware structure and / or a software module, and realize the above functions in the form of a hardware structure, a software module, or a hardware structure plus a software module. Whether one of the above functions is executed in the form of a hardware structure, a software module, or a hardware structure plus a software module depends on the specific application and design constraints of the technical solution.

[0221] Based on the above embodiments and the same technical concept, embodiments of the present application further provide a fault detection device for a three-phase power distribution system, for implementing the fault detection function of the three-phase power distribution system provided in the present application. The three-phase power distribution system includes three phase lines and a neutral line; wherein the three phase lines intersect the neutral line at a neutral point, and the three phase lines include: a first phase line, a second phase line, and a third phase line; and at least one of the three phase lines is connected to the neutral line.

[0222] Figure 7 This is a schematic diagram of a fault detection device provided in an embodiment of the present application. Figure 7 As shown, the fault detection device 700 may include a transceiver module 701 and a processing module 702:

[0223] The transceiver module 701 is used to obtain the voltage between every two phase lines;

[0224] The processing module 702 is used to determine the voltage between each phase line and the neutral point based on the voltage between each two phase lines; determine the voltage between the neutral line and the neutral point based on the voltage between each phase line and the neutral line, and the voltage between each phase line and the neutral point; and determine whether the neutral line has a broken line fault based on the voltage between the neutral line and the neutral point.

[0225] In a possible design, any phase line connected to the neutral line is connected to the neutral line through a resistance element.

[0226] In one possible design, when the transceiver module 701 obtains the voltage between each two phase lines, it is specifically used to: obtain the voltage between each phase line and the neutral line; and determine the voltage between each two phase lines based on the voltage between each phase line and the center line.

[0227] In a possible design, when the transceiver module 701 obtains the voltage between each two phase lines, it is specifically used to: obtain the voltage between the first phase line and the neutral line, the voltage between the second phase line and the neutral line, and the voltage between the first phase line and the third phase line; determine the voltage between the first phase line and the second phase line based on the voltage between the first phase line and the neutral line and the voltage between the second phase line and the neutral line; determine the voltage between the third phase line and the neutral line based on the voltage between the first phase line and the neutral line and the voltage between the first phase line and the third phase line; determine the voltage between the second phase line and the third phase line based on the voltage between the second phase line and the neutral line and the voltage between the third phase line and the neutral line.

[0228] In one possible design, the voltage between the first phase line and the second phase line satisfies the following formula:

[0229]

[0230] Wherein, V1 is the voltage between the first phase line and the second phase line, V2 is the voltage between the first phase line and the neutral line, V3 is the voltage between the second phase line and the neutral line, and θ is the phase difference between V2 and V3.

[0231] In a possible design, the voltage between the third phase line and the neutral line conforms to the following formula:

[0232]

[0233] Wherein, V4 is the voltage between the third phase line and the neutral line, V5 is the voltage between the first phase line and the neutral line, V6 is the voltage between the first phase line and the third phase line, and σ is the phase difference between V5 and V6.

[0234] In one possible design, when the processing module 702 determines the voltage between each phase line and the neutral point based on the voltage between each two phase lines, it is specifically used to: construct a target triangle model in a set coordinate system based on the voltage between each two phase lines, wherein the three side lengths of the target triangle model are the voltage between each two phase lines; determine the target point corresponding to the target triangle model in the set coordinate system, wherein the target point and the line connecting any two endpoints of the target triangle model can form an angle of 120° after intersecting; determine the distance from the target point to each endpoint in the target triangle model; and use the distance from the target point to each endpoint as the voltage value between each phase line and the neutral point.

[0235] In a possible design, if the three internal angles of the target triangular model are all less than 120°, the target point is a Fermat point of the target triangular model; or the target point is an isometric center point of the target triangular model.

[0236] In a possible design, the three side lengths of the target triangle model are the first side length, the second side length and the third side length; when the processing module determines the target point corresponding to the target triangle model in the set coordinate system, it is specifically used to: construct a first target circle model corresponding to the first side length and a second target circle model corresponding to the second side length in the set coordinate system, wherein the first target circle model includes the two endpoints of the first side length and the target point, and the second target circle model includes the two endpoints of the second side length and the target point; determine the coordinates of the center of the first target circle model according to the coordinates of the two endpoints of the first side length; and determine the coordinates of the center of the second target circle model according to the coordinates of the two endpoints of the second side length; determine the coordinates of the target point according to the coordinates of the center of the first target circle model and the coordinates of the center of the second target circle model.

[0237] In a possible design, the coordinate origin of the set coordinate system is any endpoint of the target triangle model, and a coordinate axis in the set coordinate system coincides with a side length of the target triangle model at the coordinate origin.

[0238] In one possible design, when the processing module 702 determines the voltage between the neutral line and the neutral point based on the voltage between each phase line and the neutral line, and the voltage between each phase line and the neutral point, it is specifically used to: determine the target difference corresponding to each phase line, wherein the target difference corresponding to the target phase line is the difference between the following two: the voltage between the target phase line and the neutral line, and the voltage between the target phase line and the neutral point; and take the maximum value of the target differences corresponding to the three phase lines as the voltage between the neutral line and the neutral point.

[0239] In one possible design, when the processing module 702 determines whether a disconnection fault occurs in the neutral line based on the voltage between the neutral line and the neutral point, it is specifically used to: determine whether the voltage between the neutral line and the neutral point is greater than a set threshold; if it is determined that the voltage between the neutral line and the neutral point is greater than the set threshold, it is determined that a disconnection fault occurs in the neutral line; otherwise, it is determined that no disconnection fault occurs in the neutral line.

[0240] The division of modules in the above embodiments of the present application is illustrative and is merely a logical functional division. In actual implementation, other division methods may be used. Furthermore, the functional modules in the various embodiments of the present application may be integrated into a single processor, or may exist physically separately, or two or more modules may be integrated into a single module. The above integrated modules may be implemented in the form of hardware or software functional modules.

[0241] Based on the above embodiments and the same technical concept, an embodiment of the present application further provides a fault detection device for a three-phase power distribution system, which is used to implement the fault detection function of the three-phase power distribution system provided by the present application. Figure 8 A schematic diagram of a fault detection device provided in an embodiment of the present application. The fault detection device may be a user device, or a chip or chip system in the user device.

[0242] In some embodiments of the present application, the fault detection device may also be a terminal device, a network device, an electronic device, or an integrated circuit structure that can execute the fault detection method for the three-phase power distribution system provided by the present application.

[0243] The three-phase power distribution system includes three phase lines and a neutral line; wherein the three phase lines intersect with the neutral line at a neutral point, and the three phase lines include: a first phase line, a second phase line, and a third phase line; at least one of the three phase lines is connected to the neutral line.

[0244] Exemplarily, the fault detection device 800 includes a transceiver 801 and at least one processor 802. The processor 802 and the transceiver 801 are coupled. In the embodiments of the present application, coupling is an indirect coupling or communication connection between devices, units, or modules, and can be electrical, mechanical, or other forms, for information exchange between devices, units, or modules.

[0245] Specifically, the transceiver 801 may be a circuit, a bus, a communication interface, or any other module that can be used for information interaction, and may be used to receive or send information.

[0246] Optionally, the communication device may further include a memory 803 , which is coupled to the transceiver 801 and the processor 802 and is configured to store program instructions.

[0247] The processor 802 is used to call the program instructions stored in the memory 803, so that the fault detection device 800 executes the fault detection method of the three-phase power distribution system provided in the embodiment of the present application, thereby realizing fault detection of the three-phase power distribution system.

[0248] The transceiver 801 can be used to receive and transmit radio frequency signals and is coupled to the receiver and transmitter of the communication fault detection device 800. The transceiver 801 can communicate with communication networks and other communication devices via radio frequency signals, such as Ethernet, Radio Access Technology (RAN), Wireless Local Area Networks (WLAN), etc. In a specific implementation, the communication protocols supported by the transceiver 801 may include WiFi protocol, 2G / 3G, Long Term Evolution (LTE), 5G New Radio (NR), etc. The transceiver 801 may also have certain data processing functions.

[0249] In a specific implementation, the memory 803 may include a high-speed random access memory, and may also include a non-volatile memory, such as one or more disk storage devices, flash memory devices or other non-volatile solid-state storage devices. The memory 802 may store an operating system (hereinafter referred to as system), such as an embedded operating system such as ANDROID, IOS, WINDOWS, or LINUX. The memory 803 may be used to store the implementation program of the embodiment of the present application. The memory 803 may also store a network communication program, which may be used to communicate with one or more additional devices, one or more user devices, or one or more network devices.

[0250] The processor 802 may be a general-purpose central processing unit (CPU), a microprocessor, an application-specific integrated circuit (ASIC), or one or more integrated circuits for controlling the execution of the program of the present application.

[0251] In some embodiments, the communication fault detection device 800 may further include an output device 804 and an input device 805. The output device 804 communicates with the processor 802 and can display information in a variety of ways. For example, the output device 804 may be a liquid crystal display (LCD), a light emitting diode (LED) display device, a cathode ray tube (CRT) display device, or a projector. The input device 805 communicates with the processor 802 and can receive user input in a variety of ways. For example, the input device 805 may be a mouse, a keyboard, a touch screen device, or a sensor device. To facilitate user use of the output device 804 and the input device 805, in some embodiments, the memory 803 may further store a user interface program. This user interface program can realistically display the content of the application through a graphical user interface and accept user control operations on the application through input controls such as menus, dialog boxes, and buttons.

[0252] The memory of the communication fault detection device 800 may store one or more software modules, which may be used to provide functions such as data calculation, model building, and disconnection fault judgment. For details, please refer to the above embodiments.

[0253] Exemplarily, the transceiver 801 is used to obtain the voltage between each two phase lines; the processor 802 is used to determine the voltage between each phase line and the neutral point based on the voltage between each two phase lines; determine the voltage between the neutral line and the neutral point based on the voltage between each phase line and the neutral line, and the voltage between each phase line and the neutral point; and determine whether the neutral line has a broken line fault based on the voltage between the neutral line and the neutral point.

[0254] In a possible design, any phase line connected to the neutral line is connected to the neutral line through a resistance element.

[0255] In one possible design, when the transceiver 801 obtains the voltage between each two phase lines, it is specifically used to: obtain the voltage between each phase line and the neutral line; and determine the voltage between each two phase lines based on the voltage between each phase line and the center line.

[0256] In a possible design, when the transceiver 801 obtains the voltage between each two phase lines, it is specifically used to: obtain the voltage between the first phase line and the neutral line, the voltage between the second phase line and the neutral line, and the voltage between the first phase line and the third phase line; determine the voltage between the first phase line and the second phase line based on the voltage between the first phase line and the neutral line and the voltage between the second phase line and the neutral line; determine the voltage between the third phase line and the neutral line based on the voltage between the first phase line and the neutral line and the voltage between the first phase line and the third phase line; determine the voltage between the second phase line and the third phase line based on the voltage between the second phase line and the neutral line and the voltage between the third phase line and the neutral line.

[0257] In one possible design, the voltage between the first phase line and the second phase line satisfies the following formula:

[0258]

[0259] Wherein, V1 is the voltage between the first phase line and the second phase line, V2 is the voltage between the first phase line and the neutral line, V3 is the voltage between the second phase line and the neutral line, and θ is the phase difference between V2 and V3.

[0260] In a possible design, the voltage between the third phase line and the neutral line conforms to the following formula:

[0261]

[0262] Wherein, V4 is the voltage between the third phase line and the neutral line, V5 is the voltage between the first phase line and the neutral line, V6 is the voltage between the first phase line and the third phase line, and σ is the phase difference between V5 and V6.

[0263] In one possible design, when the processor 802 determines the voltage between each phase line and the neutral point based on the voltage between each two phase lines, it is specifically used to: construct a target triangle model in a set coordinate system based on the voltage between each two phase lines, wherein the three side lengths of the target triangle model are the voltage between each two phase lines; determine the target point corresponding to the target triangle model in the set coordinate system, wherein the target point and the line connecting any two endpoints of the target triangle model can form an angle of 120° after intersecting; determine the distance from the target point to each endpoint in the target triangle model; and use the distance from the target point to each endpoint as the voltage value between each phase line and the neutral point.

[0264] In a possible design, if the three internal angles of the target triangular model are all less than 120°, the target point is a Fermat point of the target triangular model; or the target point is an isometric center point of the target triangular model.

[0265] In one possible design, the three side lengths of the target triangle model are the first side length, the second side length and the third side length; when the processor determines the target point corresponding to the target triangle model in the set coordinate system, it is specifically used to: construct a first target circle model corresponding to the first side length and a second target circle model corresponding to the second side length in the set coordinate system, wherein the first target circle model includes the two endpoints of the first side length and the target point, and the second target circle model includes the two endpoints of the second side length and the target point; determine the coordinates of the center of the first target circle model according to the coordinates of the two endpoints of the first side length; and determine the coordinates of the center of the second target circle model according to the coordinates of the two endpoints of the second side length; determine the coordinates of the target point according to the coordinates of the center of the first target circle model and the coordinates of the center of the second target circle model.

[0266] In a possible design, the coordinate origin of the set coordinate system is any endpoint of the target triangle model, and a coordinate axis in the set coordinate system coincides with a side length of the target triangle model at the coordinate origin.

[0267] In one possible design, when the processor 802 determines the voltage between the neutral line and the neutral point based on the voltage between each phase line and the neutral line, and the voltage between each phase line and the neutral point, it is specifically used to: determine the target difference corresponding to each phase line, wherein the target difference corresponding to the target phase line is the difference between the following two: the voltage between the target phase line and the neutral line, and the voltage between the target phase line and the neutral point; and take the maximum value of the target differences corresponding to the three phase lines as the voltage between the neutral line and the neutral point.

[0268] In one possible design, when the processor 802 determines whether a disconnection fault occurs in the neutral line based on the voltage between the neutral line and the neutral point, it is specifically used to: determine whether the voltage between the neutral line and the neutral point is greater than a set threshold; if it is determined that the voltage between the neutral line and the neutral point is greater than the set threshold, it is determined that a disconnection fault occurs in the neutral line; otherwise, it is determined that no disconnection fault occurs in the neutral line.

[0269] Need to explain, Figure 8 This is only one implementation of the embodiment of the present application. In actual applications, the communication device 800 may also include more or fewer components, which is not limited here.

[0270] Based on the above embodiments and the same technical concept, an embodiment of the present application also provides a computer-readable storage medium, which stores computer program instructions. When the computer program instructions are run on a fault detection device, the fault detection device executes the fault detection method for the three-phase power distribution system provided in the above embodiment.

[0271] Based on the above embodiments and the same technical concept, an embodiment of the present application also provides a computer program product. When the computer program product runs on a fault detection device, the fault detection device executes the fault detection method for the three-phase power distribution system provided in the above embodiments.

[0272] Based on the above embodiments and the same technical concept, an embodiment of the present application further provides a chip, which is used to read a computer program stored in a memory and execute the fault detection method for a three-phase power distribution system provided in the above embodiments.

[0273] Those skilled in the art will appreciate that the embodiments of the present application can be provided as methods, systems, or computer program products. Therefore, the present application can adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application can adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to magnetic disk storage, CD-ROM, optical storage, etc.) that contain computer-usable program code.

[0274] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the present application. It should be understood that each flow and / or box in the flow chart and / or block diagram, as well as the combination of the flow chart and / or box in the flow chart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device produce a device for implementing the functions specified in one or more flow charts and / or one or more boxes in the block diagram.

[0275] These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce a product including an instruction device that implements the functions specified in one or more processes in the flowchart and / or one or more boxes in the block diagram.

[0276] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, so that the instructions executed on the computer or other programmable device provide steps for implementing the functions specified in one or more processes in the flowchart and / or one or more boxes in the block diagram.

[0277] Obviously, those skilled in the art may make various modifications and variations to this application without departing from the scope of protection of this application. Thus, if such modifications and variations fall within the scope of the claims of this application and their equivalents, this application is intended to include such modifications and variations.

Claims

1. A fault detection method for a three-phase power distribution system, characterized in that: The three-phase power distribution system includes three phase lines and a neutral line; wherein the three phase lines intersect the neutral line at a neutral point, and the three phase lines include: a first phase line, a second phase line, and a third phase line; at least one of the three phase lines is connected to the neutral line; and the method includes: Get the voltage between every two phase lines; Determining the voltage between each phase line and the neutral point according to the voltage between each two phase lines; determining the voltage between the neutral line and the neutral point based on the voltage between each phase line and the neutral line and the voltage between each phase line and the neutral point; Whether a neutral line break fault occurs is determined based on the voltage between the neutral line and the neutral point.

2. The method according to claim 1, characterized in that Any phase line connected to the neutral line is connected to the neutral line through a resistance element.

3. The method according to claim 1 or 2, characterized in that Get the voltage between every two phase lines, including: obtaining the voltage between each phase line and the neutral line; The voltage between each two phase lines is determined according to the voltage between each phase line and the neutral line.

4. The method according to claim 1 or 2, characterized in that Get the voltage between every two phase lines, including: Acquire a voltage between the first phase line and the neutral line, a voltage between the second phase line and the neutral line, and a voltage between the first phase line and the third phase line; determining a voltage between the first phase line and the second phase line based on a voltage between the first phase line and the neutral line and a voltage between the second phase line and the neutral line; determining a voltage between the third phase line and the neutral line according to a voltage between the first phase line and the neutral line and a voltage between the first phase line and the third phase line; The voltage between the second phase line and the third phase line is determined based on the voltage between the second phase line and the neutral line and the voltage between the third phase line and the neutral line.

5. The method according to claim 3 or 4, characterized in that The voltage between the first phase line and the second phase line meets the following formula: Wherein, V1 is the voltage between the first phase line and the second phase line, V2 is the voltage between the first phase line and the neutral line, V3 is the voltage between the second phase line and the neutral line, and θ is the phase difference between V2 and V3.

6. The method according to any one of claims 1 to 5, characterized in that: Determining the voltage between each phase line and the neutral point according to the voltage between each two phase lines, including: According to the voltage between every two phase lines, a target triangle model is constructed in a set coordinate system, wherein the three side lengths of the target triangle model are the voltage between every two phase lines respectively; In the set coordinate system, determining a target point corresponding to the target triangle model, wherein the target point and a line connecting any two endpoints of the target triangle model can form an angle of 120° after intersecting; Determine the distance from the target point to each endpoint in the target triangle model; The distance from the target point to each endpoint is respectively used as the voltage value between each phase line and the neutral point.

7. The method according to claim 6, characterized in that If the three internal angles of the target triangle model are all less than 120°, the target point is a Fermat point of the target triangle model; or The target point is the isotropic center point of the target triangle model.

8. The method according to claim 6 or 7, characterized in that The three side lengths of the target triangle model are a first side length, a second side length, and a third side length; and determining a target point corresponding to the target triangle model in the set coordinate system includes: In the set coordinate system, constructing a first target circle model corresponding to the first side length and a second target circle model corresponding to the second side length, wherein the first target circle model includes two endpoints of the first side length and the target point, and the second target circle model includes two endpoints of the second side length and the target point; Determining the coordinates of the center of the first target circle model based on the coordinates of the two endpoints of the first side length; and determining the coordinates of the center of the second target circle model based on the coordinates of the two endpoints of the second side length; The coordinates of the target point are determined according to the coordinates of the center of the first target circle model and the coordinates of the center of the second target circle model.

9. The method according to any one of claims 6 to 8, characterized in that: The coordinate origin of the set coordinate system is any endpoint of the target triangle model, and a coordinate axis in the set coordinate system coincides with a side length of the target triangle model at the coordinate origin.

10. The method according to any one of claims 1 to 9, characterized in that: Determining the voltage between the neutral line and the neutral point based on the voltage between each phase line and the neutral line and the voltage between each phase line and the neutral point includes: Determine a target difference value corresponding to each phase line, wherein the target difference value corresponding to the target phase line is a difference between: a voltage between the target phase line and the neutral line, and a voltage between the target phase line and the neutral point; The maximum value of the target differences corresponding to the three phase lines is used as the voltage between the neutral line and the neutral point.

11. The method according to any one of claims 1 to 10, characterized in that: Determining whether a neutral line disconnection fault occurs according to a voltage between the neutral line and the neutral point includes: Determining whether the voltage between the neutral line and the neutral point is greater than a set threshold; If it is determined that the voltage between the neutral line and the neutral point is greater than the set threshold, it is determined that a disconnection fault occurs in the neutral line; otherwise, it is determined that no disconnection fault occurs in the neutral line.

12. A fault detection device for a three-phase power distribution system, characterized in that: The three-phase power distribution system includes three phase lines and a neutral line; wherein the three phase lines intersect the neutral line at a neutral point, and the three phase lines include: a first phase line, a second phase line, and a third phase line; at least one of the three phase lines is connected to the neutral line; The fault detection device includes a transceiver module and a processing module; The transceiver module is used to obtain the voltage between every two phase lines; The processing module is used to determine the voltage between each phase line and the neutral point based on the voltage between each two phase lines; determine the voltage between the neutral line and the neutral point based on the voltage between each phase line and the neutral line, and the voltage between each phase line and the neutral point; and determine whether the neutral line has a broken line fault based on the voltage between the neutral line and the neutral point.

13. The fault detection device according to claim 12, characterized in that: Any phase line connected to the neutral line is connected to the neutral line through a resistance element.

14. The fault detection device according to claim 12 or 13, characterized in that: When the transceiver module obtains the voltage between each two phase lines, it is specifically used to: obtaining the voltage between each phase line and the neutral line; The voltage between each two phase lines is determined according to the voltage between each phase line and the neutral line.

15. The fault detection device according to claim 12 or 13, characterized in that: When the transceiver module obtains the voltage between each two phase lines, it is specifically used to: Acquire a voltage between the first phase line and the neutral line, a voltage between the second phase line and the neutral line, and a voltage between the first phase line and the third phase line; determining a voltage between the first phase line and the second phase line based on a voltage between the first phase line and the neutral line and a voltage between the second phase line and the neutral line; determining a voltage between the third phase line and the neutral line according to a voltage between the first phase line and the neutral line and a voltage between the first phase line and the third phase line; The voltage between the second phase line and the third phase line is determined based on the voltage between the second phase line and the neutral line and the voltage between the third phase line and the neutral line.

16. The fault detection device according to claim 14 or 15, characterized in that: The voltage between the first phase line and the second phase line meets the following formula: Wherein, V1 is the voltage between the first phase line and the second phase line, V2 is the voltage between the first phase line and the neutral line, V3 is the voltage between the second phase line and the neutral line, and θ is the phase difference between V2 and V3.

17. The fault detection device according to any one of claims 12 to 16, characterized in that: When the processing module determines the voltage between each phase line and the neutral point based on the voltage between each two phase lines, it is specifically used to: According to the voltage between every two phase lines, a target triangle model is constructed in a set coordinate system, wherein the three side lengths of the target triangle model are the voltage between every two phase lines respectively; In the set coordinate system, determining a target point corresponding to the target triangle model, wherein the target point and a line connecting any two endpoints of the target triangle model can form an angle of 120° after intersecting; Determine the distance from the target point to each endpoint in the target triangle model; The distance from the target point to each endpoint is respectively used as the voltage value between each phase line and the neutral point.

18. The fault detection device according to claim 17, characterized in that: If the three internal angles of the target triangle model are all less than 120°, the target point is a Fermat point of the target triangle model; or The target point is the isotropic center point of the target triangle model.

19. The fault detection device according to claim 17 or 18, characterized in that: The three side lengths of the target triangle model are a first side length, a second side length, and a third side length; and when the processing module determines the target point corresponding to the target triangle model in the set coordinate system, it is specifically configured to: In the set coordinate system, constructing a first target circle model corresponding to the first side length and a second target circle model corresponding to the second side length, wherein the first target circle model includes two endpoints of the first side length and the target point, and the second target circle model includes two endpoints of the second side length and the target point; Determining the coordinates of the center of the first target circle model based on the coordinates of the two endpoints of the first side length; and determining the coordinates of the center of the second target circle model based on the coordinates of the two endpoints of the second side length; The coordinates of the target point are determined according to the coordinates of the center of the first target circle model and the coordinates of the center of the second target circle model.

20. The fault detection device according to any one of claims 17 to 19, characterized in that: The coordinate origin of the set coordinate system is any endpoint of the target triangle model, and a coordinate axis in the set coordinate system coincides with a side length of the target triangle model at the coordinate origin.

21. The fault detection device according to any one of claims 12 to 20, characterized in that: When the processing module determines the voltage between the neutral line and the neutral point based on the voltage between each phase line and the neutral line and the voltage between each phase line and the neutral point, it is specifically used to: Determine a target difference value corresponding to each phase line, wherein the target difference value corresponding to the target phase line is a difference between: a voltage between the target phase line and the neutral line, and a voltage between the target phase line and the neutral point; The maximum value of the target differences corresponding to the three phase lines is used as the voltage between the neutral line and the neutral point.

22. The fault detection device according to any one of claims 12 to 21, characterized in that: When the processing module determines whether a neutral line disconnection fault occurs based on the voltage between the neutral line and the neutral point, it is specifically configured to: Determining whether the voltage between the neutral line and the neutral point is greater than a set threshold; If it is determined that the voltage between the neutral line and the neutral point is greater than the set threshold, it is determined that a disconnection fault occurs in the neutral line; otherwise, it is determined that no disconnection fault occurs in the neutral line.

23. A computer-readable storage medium, characterized in that The computer-readable storage medium stores computer program instructions, and when the computer program instructions are executed on the fault detection device, the fault detection device is caused to execute the method according to any one of claims 1 to 11.

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