Three-phase switch device and method capable of monitoring voltage abnormity caused by null line virtual connection

Abstract

The invention relates to the technical field of power equipment detection equipment, in particular to a three-phase switch device and method capable of monitoring voltage abnormity caused by null line virtual connection, and the three-phase switch device comprises a first voltage detection unit, a second voltage detection unit, a data processing module, a control module and an alarm unit. The virtual connection of the null line can be judged through the data processing module only by measuring the voltage values of the phase voltage UA, the phase voltage UB, the phase voltage UC, the line voltage UAB, the line voltage UBC and the line voltage UCA, before the virtual connection of the null line is judged, whether the phase line is abnormal or not is firstly determined, and the abnormal conditions of the phase voltage and the line voltage caused by phase line faults are eliminated.

Description

Technical Field

[0001] The present application relates to the technical field of power equipment detection equipment, and in particular to a three-phase switch device and method capable of monitoring voltage anomalies caused by virtual connection of a neutral line. Background Art

[0002] The statements in this section merely provide background technical information related to the present application and do not necessarily constitute prior art.

[0003] A virtual connection of the neutral line is equivalent to adding an extra resistor in the circuit, which will increase the impedance of the entire circuit. For electrical equipment with heavy loads, the current flowing through the neutral line is large, and even a small contact resistance will produce a large voltage drop on the neutral line, causing the voltage at the end of the electrical equipment to be lower than normal. In a three-phase four-wire power supply system, the correct connection of the neutral line is essential to maintain the balance of the three-phase voltage. If the neutral line is virtual connected, this balance will be destroyed, causing some phase voltages to increase and some phase voltages to decrease, causing voltage instability. This effect is especially obvious when the load is unbalanced.

[0004] In the prior art, the determination of virtual connection of the neutral line is generally performed in combination with the voltage between the neutral line and the phase line. However, this determination method is easily affected by a phase line fault because when a phase line fault occurs, the phase voltage will also change.

[0005] In view of this, it is necessary to provide a three-phase switch device and method that can monitor voltage anomalies caused by virtual connection of the neutral line to solve the above technical problems. Summary of the invention

[0006] Based on this, in order to solve the above technical problems, the present application provides a three-phase switch device and method that can monitor voltage anomalies caused by virtual connection of the neutral line.

[0007] The technical solution adopted by this application to solve the problems existing in the prior art is:

[0008] The present application proposes a three-phase switch device capable of monitoring voltage anomalies caused by virtual connection of a neutral line, comprising:

[0009] The first voltage detection unit is used to obtain the line voltage U AB , line voltage U BC And line voltage U CA Voltage value;

[0010] The second voltage detection unit is used to obtain the phase voltage U A , phase voltage U B , phase voltage U C and neutral voltage U N Voltage value;

[0011] A data processing module is used to compare each voltage value obtained by the first voltage detection unit with a set threshold value U max Perform one-to-one comparison and two-to-two comparison of each voltage value, and send the phase line abnormality information to the control module when an abnormality occurs;

[0012] The phase voltage U obtained by the second voltage detection unit is used to A , phase voltage U B And phase voltage U C The voltage values ​​are respectively related to the set threshold U avg Compare one by one; the zero line voltage U N The voltage value and the set threshold U NN For comparison, the phase voltage U A , phase voltage U B And phase voltage U C The voltage values ​​are compared in pairs; when an abnormality occurs, the zero line abnormality information is sent to the control module;

[0013] The control module is used to receive the phase line abnormality information and the neutral line abnormality information sent by the data processing module, and control the alarm unit to issue the phase line abnormality alarm information when the phase line abnormality information is received; and control the alarm unit to issue the neutral line virtual connection alarm information when the neutral line abnormality information is received and the phase line abnormality alarm information is not received.

[0014] Preferably, the data processing module processes the data of each voltage including the following steps:

[0015] S1: The line voltage U AB , line voltage U BC and line voltage U CA The voltage value and the set threshold U max Compare one by one:

[0016] U AB -U max =β1;

[0017] U BC -U max =β2;

[0018] U CA -U max =β3;

[0019] If β1∈Q, β2∈Q and β3∈Q, the data enters step S2 normally, otherwise the phase line abnormality information is sent to the control module;

[0020] Where Q = [u1, u2], u1 is the minimum allowable value of the line voltage, u2 is the maximum allowable value of the line voltage; Q is the allowable fluctuation range of the line voltage;

[0021] S2: The line voltage UAB , line voltage U BC And line voltage U CA The voltage values ​​are compared pairwise:

[0022] U AB -U BC =γ1;

[0023] U BC -U CA =γ2;

[0024] U CA -U AB =γ3;

[0025] If γ1∈P, γ2∈P and γ3∈P, the data enters step S3 normally, otherwise the phase line abnormality information is sent to the control module;

[0026] Where P = [c1, c2], c1 is the minimum allowable difference in line voltage, c2 is the maximum allowable difference in line voltage; P is the allowable fluctuation range of the line voltage difference;

[0027] S3: The phase voltage U obtained by the second voltage detection unit A , phase voltage U B And phase voltage U C The voltage values ​​are respectively related to the set threshold U avg Compare one by one; N The voltage value and the set threshold U NN For comparison, the phase voltage U A , phase voltage U B And phase voltage U C The voltage values ​​are compared in pairs; when an abnormality occurs, the zero line abnormality information is sent to the control module.

[0028] Preferably, S3 comprises the following steps:

[0029] S31: The phase voltage U A , phase voltage U B And phase voltage U C The voltage values ​​are respectively related to the set threshold U avg Compare one by one:

[0030] U A -U avg =α1;

[0031] U B -U avg =α2;

[0032] U C -U avg =α3;

[0033] The neutral voltage U N The voltage value and the set threshold U NN For comparison:

[0034] U N -U NN =α4;

[0035] If α1∈T, α2∈T, α3∈T and α4=0, the data enters step S32 normally, otherwise the zero line abnormality information is sent to the control module;

[0036] S32: The phase voltage U A , phase voltage U B And phase voltage U C The voltage values ​​are compared pairwise:

[0037] U A -U B =δ1;

[0038] U B -U C =δ2;

[0039] U C -U A =δ3;

[0040] If δ1∈D, δ2∈D and δ3∈D, the data is normal and the process returns to step S1, otherwise the phase line abnormality information is sent to the control module;

[0041] Where: D = [d1, d2], d1 is the minimum allowable difference between phase voltages, d2 is the maximum allowable difference between phase voltages; D is the allowable fluctuation range of the phase voltage difference.

[0042] Preferably, it also includes:

[0043] A housing, comprising an upper wire inlet and a lower wire outlet;

[0044] A circuit breaker is fixedly arranged in the housing, and an upper line terminal of the circuit breaker is electrically connected to an external power supply;

[0045] The power distribution equipment includes a plurality of air switches, the air switches are electrically connected to the circuit breakers, the output end of the air switches is connected to one end of the power distribution line, and the power distribution line is connected to the power consumption equipment after being led out from the lower outlet of the housing;

[0046] The first voltage detection unit, the second voltage detection unit, the data processing module, the control module and the alarm unit are arranged in the shell.

[0047] Preferably, the voltages detected by the first voltage detection unit and the second voltage detection unit are both voltages on the line before entering the circuit breaker.

[0048] Preferably, the control module and the alarm unit are connected to the DTU module through the MQTT protocol; the DTU module is wirelessly connected to the cloud platform; the cloud platform is wirelessly connected to the applet on the mobile phone of the operation and maintenance personnel;

[0049] When the alarm unit sends out an alarm message, the operation and maintenance personnel can receive the alarm message through the mini program on the mobile phone.

[0050] Preferably, it also includes a zero-sequence current transformer, which is used to detect three-phase unbalanced current; when the zero-sequence current transformer detects that the three-phase unbalanced current is not equal to zero, the control module controls the alarm unit to issue a zero-line virtual connection alarm message.

[0051] Preferably, the zero-sequence current transformer is sleeved outside the three phase lines above the circuit breaker.

[0052] Preferably, the zero-sequence current transformer is an open-type zero-sequence current transformer.

[0053] A method for monitoring voltage anomalies caused by virtual connection of a neutral line comprises the following steps:

[0054] S10: Get line voltage U AB , line voltage U BC And line voltage U CA The voltage value of the line voltage U AB , line voltage U BC And line voltage U CA With the threshold value U max Compare one by one:

[0055] U AB -U max =β1;

[0056] U BC -U max =β2;

[0057] U CA -U max =β3;

[0058] If β1∈Q, β2∈Q and β3∈Q, the data enters step S2 normally, otherwise the phase line abnormality information is sent to the control module;

[0059] Where Q = [u1, u2], u1 is the minimum allowable value of the line voltage, u2 is the maximum allowable value of the line voltage; Q is the allowable fluctuation range of the line voltage;

[0060] S11: The line voltage U AB , line voltage U BC And line voltage U CA The voltage values ​​are compared pairwise:

[0061] U AB -U BC =γ1;

[0062] U BC -U CA =γ2;

[0063] U CA -U AB =γ3;

[0064] If γ1∈P, γ2∈P and γ3∈P, the data enters step S12 normally, otherwise the phase line abnormality information is sent to the control module;

[0065] Where P = [c1, c2], c1 is the minimum allowable difference in line voltage, c2 is the maximum allowable difference in line voltage; P is the allowable fluctuation range of the line voltage difference;

[0066] S12: Get phase voltage U A , phase voltage U B And phase voltage U C The voltage value of the phase voltage U A , phase voltage U B And phase voltage U C The voltage values ​​are respectively related to the set threshold U avg Compare one by one:

[0067] U A -U avg =α1;

[0068] U B -U avg =α2;

[0069] U C -U avg =α3;

[0070] The neutral voltage U N The voltage value and the set threshold U NN For comparison:

[0071] U N -U NN =α4;

[0072] If α1∈T, α2∈T, α3∈T and α4=0, the data enters step S13 normally, otherwise the zero line abnormality information is sent to the control module;

[0073] S13: The phase voltage U A , phase voltage U B And phase voltage U C The voltage values ​​are compared pairwise:

[0074] UA -U B =δ1;

[0075] U B -U C =δ2;

[0076] U C -U A =δ3;

[0077] If δ1∈D, δ2∈D and δ3∈D, the data is normal and the process returns to step S10, otherwise the phase line abnormality information is sent to the control module;

[0078] Where: D = [d1, d2], d1 is the minimum allowable difference between phase voltages, d2 is the maximum allowable difference between phase voltages; D is the allowable fluctuation range of the phase voltage difference.

[0079] Compared with the prior art, the beneficial effects of this application are:

[0080] 1. Before judging whether the neutral line is loosely connected, first determine whether the phase line is abnormal, and eliminate the abnormal conditions of phase voltage and line voltage caused by phase line fault.

[0081] 2. The judgment process is simple, only the phase voltage U A , phase voltage U B And phase voltage U C And the line voltage U AB , line voltage U BC And line voltage U CA The voltage value of the neutral line can be used to determine whether the neutral line is virtually connected through the data processing module.

[0082] 3. The MQTT protocol is highly real-time. When it is determined that the neutral line is loosely connected, the operation and maintenance personnel will be notified through the mini program, and the warning will be timely. BRIEF DESCRIPTION OF THE DRAWINGS

[0083] The drawings in the specification, which constitute a part of the present application, are used to provide further understanding of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute improper limitations on the present application.

[0084] Figure 1 This is a judgment flow chart of a method for monitoring voltage anomalies caused by virtual connection of a neutral line in the present application. DETAILED DESCRIPTION

[0085] The present application is further described below in conjunction with the accompanying drawings and embodiments.

[0086] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present disclosure. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0087] In the present disclosure, terms such as "upper", "lower", "left", "right", "front", "back", "vertical", "horizontal", "side", "bottom" and the like indicating directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings. They are relational words determined only for the convenience of describing the structural relationships of the various parts or elements of the present disclosure, and do not specifically refer to any part or element in the present disclosure and should not be understood as limitations on the present disclosure.

[0088] A three-phase switch device capable of monitoring voltage abnormality caused by virtual connection of a neutral line in the present application comprises:

[0089] The first voltage detection unit is used to obtain the line voltage U AB , line voltage U BC and line voltage U CA Voltage value;

[0090] The second voltage detection unit is used to obtain the phase voltage U A , phase voltage U B , phase voltage U C and neutral voltage U N Voltage value;

[0091] A data processing module is used to compare each voltage value obtained by the first voltage detection unit with a set threshold value U max Perform one-to-one comparison and two-to-two comparison of each voltage value, and send the phase line abnormality information to the control module when an abnormality occurs;

[0092] The phase voltage U obtained by the second voltage detection unit is used to A , phase voltage U B And phase voltage U C The voltage values ​​are respectively related to the set threshold U avg Compare one by one; the zero line voltage U N The voltage value and the set threshold U NN For comparison, the phase voltage U A , phase voltage U B And phase voltage U C The voltage values ​​are compared in pairs; when an abnormality occurs, the zero line abnormality information is sent to the control module;

[0093] The control module is used to receive the phase line abnormality information and the neutral line abnormality information sent by the data processing module, and control the alarm unit to issue the phase line abnormality alarm information when the phase line abnormality information is received; and control the alarm unit to issue the neutral line virtual connection alarm information when the neutral line abnormality information is received and the phase line abnormality alarm information is not received.

[0094] The data processing module processes the data of each voltage including the following steps:

[0095] S1: The line voltage U AB , line voltage U BC And line voltage U CA The voltage value and the set threshold U max Compare one by one:

[0096] U AB -U max =β1;

[0097] U BC -U max =β2;

[0098] U CA -U max =β3;

[0099] If β1∈Q, β2∈Q and β3∈Q, the data enters step S2 normally, otherwise the phase line abnormality information is sent to the control module;

[0100] Where Q = [u1, u2], u1 is the minimum allowable value of the line voltage, u2 is the maximum allowable value of the line voltage; Q is the allowable fluctuation range of the line voltage;

[0101] S2: The line voltage U AB , line voltage U BC And line voltage U CA The voltage values ​​are compared pairwise:

[0102] U AB -U BC =γ1;

[0103] U BC -U CA =γ2;

[0104] U CA -U AB =γ3;

[0105] If γ1∈P, γ2∈P and γ3∈P, the data enters step S3 normally, otherwise the phase line abnormality information is sent to the control module;

[0106] Where P = [c1, c2], c1 is the minimum allowable difference in line voltage, c2 is the maximum allowable difference in line voltage; P is the allowable fluctuation range of the line voltage difference;

[0107] S3: The phase voltage U obtained by the second voltage detection unit A , phase voltage U B And phase voltage U C The voltage values ​​are respectively related to the set threshold U avg Compare one by one; N The voltage value and the set threshold U NN For comparison, the phase voltage U A , phase voltage U B And phase voltage U C The voltage values ​​are compared in pairs; when an abnormality occurs, the zero line abnormality information is sent to the control module.

[0108] The S3 comprises the following steps:

[0109] S31: The phase voltage U A , phase voltage U B And phase voltage U C The voltage values ​​are respectively related to the set threshold U avg Compare one by one:

[0110] U A -U avg =α1;

[0111] U B -U avg =α2;

[0112] U C -U avg =α3;

[0113] The neutral voltage U N The voltage value and the set threshold U NN For comparison:

[0114] U N -U NN =α4;

[0115] If α1∈T, α2∈T, α3∈T and α4=0, the data enters step S32 normally, otherwise the zero line abnormality information is sent to the control module;

[0116] S32: The phase voltage U A , phase voltage U B And phase voltage U C The voltage values ​​are compared pairwise:

[0117] U A -U B=δ1;

[0118] U B -U C =δ2;

[0119] U C -U A =δ3;

[0120] If δ1∈D, δ2∈D and δ3∈D, the data is normal and the process returns to step S1, otherwise the phase line abnormality information is sent to the control module;

[0121] Where: D = [d1, d2], d1 is the minimum allowable difference between phase voltages, d2 is the maximum allowable difference between phase voltages; D is the allowable fluctuation range of the phase voltage difference.

[0122] In some embodiments, a three-phase switch device capable of monitoring voltage abnormality caused by virtual connection of a neutral line of the present application further includes:

[0123] A housing, comprising an upper wire inlet and a lower wire outlet;

[0124] The circuit breaker is fixedly arranged in the housing, and the upper incoming terminal of the circuit breaker is electrically connected to the external power supply; the power distribution equipment includes a plurality of air switches, the air switches are electrically connected to the circuit breaker, the output end of the air switch is connected to one end of the power distribution line, and the power distribution line is connected to the power consumption equipment after being led out from the lower outlet of the housing; the first voltage detection unit, the second voltage detection unit, the data processing module, the control module and the alarm unit are arranged in the housing. The voltages detected by the first voltage detection unit and the second voltage detection unit are both the voltages on the line before entering the circuit breaker.

[0125] In some embodiments, the control module and the alarm unit are connected to the DTU module via the MQTT protocol; the DTU module is wirelessly connected to the cloud platform; the cloud platform is wirelessly connected to the mini-program on the mobile phone of the operation and maintenance personnel; when the alarm unit issues an alarm message, the operation and maintenance personnel can receive the alarm message through the mini-program on the mobile phone.

[0126] In some embodiments, a three-phase switching device of the present application that can monitor voltage anomalies caused by virtual connection of the neutral line also includes a zero-sequence current transformer, which is used to detect three-phase unbalanced current; when the zero-sequence current transformer detects that the three-phase unbalanced current is not equal to zero, the control module controls the alarm unit to issue a neutral line virtual connection alarm message.

[0127] The zero-sequence current transformer is sleeved outside the three phase lines above the circuit breaker.

[0128] In some embodiments, the zero-sequence current transformer is an open-type zero-sequence current transformer to facilitate secondary installation after the line is installed.

[0129] The present application also provides a method for monitoring voltage anomalies caused by virtual connection of the neutral line. Based on the above-mentioned three-phase switch device capable of monitoring voltage anomalies caused by virtual connection of the neutral line, reference is made to Figure 1 , Figure 1 This is a judgment flow chart of a method for monitoring voltage anomalies caused by virtual connection of the neutral line in the present application. The method for monitoring voltage anomalies caused by virtual connection of the neutral line in the present application includes the following steps:

[0130] S10: Get line voltage U AB , line voltage U BC And line voltage U CA The voltage value of the line voltage U AB , line voltage U BC And line voltage U CA With the threshold value U max Compare one by one:

[0131] U AB -U max =β1;

[0132] U BC -U max =β2;

[0133] U CA -U max =β3;

[0134] If β1∈Q, β2∈Q and β3∈Q, the data enters step S2 normally, otherwise the phase line abnormality information is sent to the control module;

[0135] Where Q = [u1, u2], u1 is the minimum allowable value of the line voltage, u2 is the maximum allowable value of the line voltage; Q is the allowable fluctuation range of the line voltage;

[0136] S11: The line voltage U AB , line voltage U BC And line voltage U CA The voltage values ​​are compared pairwise:

[0137] U AB -U BC =γ1;

[0138] U BC -U CA =γ2;

[0139] U CA -U AB =γ3;

[0140] If γ1∈P, γ2∈P and γ3∈P, the data enters step S12 normally, otherwise the phase line abnormality information is sent to the control module;

[0141] Where P = [c1, c2], c1 is the minimum allowable difference in line voltage, c2 is the maximum allowable difference in line voltage; P is the allowable fluctuation range of the line voltage difference;

[0142] S12: Get phase voltage U A , phase voltage U B And phase voltage U C The voltage value of the phase voltage U A , phase voltage U B And phase voltage U C The voltage values ​​are respectively related to the set threshold U avg Compare one by one:

[0143] U A -U avg =α1;

[0144] U B -U avg =α2;

[0145] U C -U avg =α3;

[0146] The neutral voltage U N The voltage value and the set threshold U NN For comparison:

[0147] U N -U NN =α4;

[0148] If α1∈T, α2∈T, α3∈T and α4=0, the data enters step S13 normally, otherwise the zero line abnormality information is sent to the control module;

[0149] S13: The phase voltage U A , phase voltage U B And phase voltage U C The voltage values ​​are compared pairwise:

[0150] U A -U B =δ1;

[0151] U B -U C =δ2;

[0152] U C -U A =δ3;

[0153] If δ1∈D, δ2∈D and δ3∈D, the data is normal and the process returns to step S10, otherwise the phase line abnormality information is sent to the control module;

[0154] Where: D = [d1, d2], d1 is the minimum allowable difference between phase voltages, d2 is the maximum allowable difference between phase voltages; D is the allowable fluctuation range of the phase voltage difference.

[0155] The present invention discloses a three-phase switch device and method capable of monitoring voltage abnormality caused by virtual connection of the neutral line. Before judging whether the neutral line is virtual connected, first determine whether the phase line is abnormal, and exclude the abnormal conditions of phase voltage and line voltage caused by phase line fault. The judgment process is simple, and only needs to measure the phase voltage U A , phase voltage U B And phase voltage U C And the line voltage U AB , line voltage U BC And line voltage U CA The voltage value of the neutral line can be used to determine whether the neutral line is virtually connected through the data processing module.

[0156] The above are only preferred embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

[0157] Although the above describes the specific implementation methods of the present application in conjunction with the accompanying drawings, it is not intended to limit the scope of protection of the present application. Technical personnel in the relevant field should understand that on the basis of the technical solution of the present application, various modifications or deformations that can be made by technical personnel in this field without creative work are still within the scope of protection of the present application.

Claims

1. A three-phase switch device capable of monitoring voltage anomalies caused by virtual connection of the neutral line, characterized in that: include: The first voltage detection unit is used to obtain the line voltage U AB , line voltage U BC and line voltage U CA Voltage value; The second voltage detection unit is used to obtain the phase voltage U A , phase voltage U B , phase voltage U C and neutral voltage U N Voltage value; A data processing module is used to compare each voltage value obtained by the first voltage detection unit with a set threshold value U max Perform one-to-one comparison and two-to-two comparison of each voltage value, and send the phase line abnormality information to the control module when an abnormality occurs; The phase voltage U obtained by the second voltage detection unit is used to A , phase voltage U B And phase voltage U C The voltage values ​​are respectively related to the set threshold U avg Compare one by one; N The voltage value and the set threshold U NN For comparison, the phase voltage U A , phase voltage U B And phase voltage U C The voltage values ​​are compared in pairs; when an abnormality occurs, the zero line abnormality information is sent to the control module; The control module is used to receive the phase line abnormality information and the neutral line abnormality information sent by the data processing module, and control the alarm unit to issue the phase line abnormality alarm information when the phase line abnormality information is received; and control the alarm unit to issue the neutral line virtual connection alarm information when the neutral line abnormality information is received and the phase line abnormality alarm information is not received.

2. A three-phase switch device capable of monitoring voltage abnormality caused by virtual connection of the neutral line according to claim 1, characterized in that: The data processing module processes the data of each voltage including the following steps: S1: The line voltage U AB , line voltage U BC and line voltage U CA The voltage value and the set threshold U max Compare one by one: And AB -U max =β1; U BC -U max =β2; U CA -U max =β3; If β1∈Q, β2∈Q and β3∈Q, the data enters step S2 normally, otherwise the phase line abnormality information is sent to the control module; Where Q = [u1, u2], u1 is the minimum allowable value of the line voltage, u2 is the maximum allowable value of the line voltage; Q is the allowable fluctuation range of the line voltage; S2: Line voltage U AB , line voltage U BC and line voltage U CA The voltage values ​​are compared pairwise: U AB -U BC = γ1; U BC -U CA =γ2; IN CA -IN AB =γ3; If γ1∈P, γ2∈P and γ3∈P, the data enters step S3 normally, otherwise the phase line abnormality information is sent to the control module; Where P = [c1, c2], c1 is the minimum allowable difference in line voltage, c2 is the maximum allowable difference in line voltage; P is the allowable fluctuation range of the line voltage difference; S3: The phase voltage U obtained by the second voltage detection unit A , phase voltage U B And phase voltage U C The voltage values ​​are respectively related to the set threshold U avg Compare one by one; N The voltage value and the set threshold U NN For comparison, the phase voltage U A , phase voltage U B And phase voltage U C The voltage values ​​are compared in pairs; when an abnormality occurs, the zero line abnormality information is sent to the control module.

3. A three-phase switch device capable of monitoring voltage abnormality caused by virtual connection of the neutral line according to claim 2, characterized in that: The S3 comprises the following steps: S31: The phase voltage U A , phase voltage U B And phase voltage U C The voltage values ​​are respectively related to the set threshold U avg Compare one by one: IN A -IN avg =α1; U B -U avg =α2; U C -U avg =α3; The neutral voltage U N The voltage value and the set threshold U NN For comparison: U N -U NN =α4; If α1∈T, α2∈T, α3∈T and α4=0, the data enters step S32 normally, otherwise the zero line abnormality information is sent to the control module; S32: The phase voltage U A , phase voltage U B And phase voltage U C The voltage values ​​are compared pairwise: The A -U B =δ1; IN B -IN C =δ2; The C -U A =δ3; If δ1∈D, δ2∈D and δ3∈D, the data is normal and the process returns to step S1, otherwise the phase line abnormality information is sent to the control module; Where: D = [d1, d2], d1 is the minimum allowable difference between phase voltages, d2 is the maximum allowable difference between phase voltages; D is the allowable fluctuation range of the phase voltage difference.

4. A three-phase switch device capable of monitoring voltage abnormality caused by virtual connection of the neutral line according to claim 1, characterized in that: Also includes: A housing, comprising an upper wire inlet and a lower wire outlet; A circuit breaker is fixedly arranged in the housing, and an upper line terminal of the circuit breaker is electrically connected to an external power supply; The power distribution equipment includes a plurality of air switches, the air switches are electrically connected to the circuit breakers, the output end of the air switches is connected to one end of the power distribution line, and the power distribution line is connected to the power consumption equipment after being led out from the lower outlet of the housing; The first voltage detection unit, the second voltage detection unit, the data processing module, the control module and the alarm unit are arranged in the shell.

5. A three-phase switch device capable of monitoring voltage abnormality caused by virtual connection of the neutral line according to claim 4, characterized in that: The voltages detected by the first voltage detection unit and the second voltage detection unit are both voltages on the line before entering the circuit breaker.

6. A three-phase switch device capable of monitoring voltage anomalies caused by virtual connection of the neutral line according to claim 4, characterized in that: The control module and the alarm unit are connected to the DTU module through the MQTT protocol; the DTU module is wirelessly connected to the cloud platform; the cloud platform is wirelessly connected to the applet on the mobile phone of the operation and maintenance personnel; When the alarm unit sends out an alarm message, the operation and maintenance personnel can receive the alarm message through the mini program on the mobile phone.

7. A three-phase switch device capable of monitoring voltage abnormality caused by virtual connection of the neutral line according to claim 4, characterized in that: It also includes a zero-sequence current transformer, which is used to detect three-phase unbalanced current; when the zero-sequence current transformer detects that the three-phase unbalanced current is not equal to zero, the control module controls the alarm unit to issue a zero-line virtual connection alarm message.

8. A three-phase switch device capable of monitoring voltage anomalies caused by virtual connection of the neutral line according to claim 7, characterized in that: The zero-sequence current transformer is sleeved outside the three phase lines above the circuit breaker.

9. A three-phase switch device capable of monitoring voltage anomalies caused by virtual connection of the neutral line according to claim 8, characterized in that: The zero-sequence current transformer is an open-type zero-sequence current transformer.

10. A method for monitoring voltage anomalies caused by virtual connection of a neutral line, based on a three-phase switch device capable of monitoring voltage anomalies caused by virtual connection of a neutral line as claimed in any one of claims 1 to 8 above, characterized in that: The following steps are involved: S10: Get line voltage U AB , line voltage U BC and line voltage U CA The voltage value of the line voltage U AB , line voltage U BC and line voltage U CA With the threshold value U max Compare one by one: And AB -U max =β1; U BC -U max =β2; U CA -U max =β3; If β1∈Q, β2∈Q and β3∈Q, the data enters step S2 normally, otherwise the phase line abnormality information is sent to the control module; Where Q = [u1, u2], u1 is the minimum allowable value of the line voltage, u2 is the maximum allowable value of the line voltage; Q is the allowable fluctuation range of the line voltage; S11: The line voltage U AB , line voltage U BC and line voltage U CA The voltage values ​​are compared pairwise: U AB -U BC = γ1; U BC -U CA =γ2; IN CA -IN AB =γ3; If γ1∈P, γ2∈P and γ3∈P, the data enters step S12 normally, otherwise the phase line abnormality information is sent to the control module; Where P = [c1, c2], c1 is the minimum allowable difference in line voltage, c2 is the maximum allowable difference in line voltage; P is the allowable fluctuation range of the line voltage difference; S12: Get phase voltage U A , phase voltage U B And phase voltage U C The voltage value of the phase voltage U A , phase voltage U B And phase voltage U C The voltage values ​​are respectively related to the set threshold U avg Compare one by one: IN A -IN avg =α1; U B -U avg =α2; U C -U avg =α3; The neutral voltage U N The voltage value and the set threshold U NN For comparison: U N -U NN =α4; If α1∈T, α2∈T, α3∈T and α4=0, the data enters step S13 normally, otherwise the zero line abnormality information is sent to the control module; S13: The phase voltage U A , phase voltage U B And phase voltage U C The voltage values ​​are compared pairwise: The A -U B =δ1; IN B -IN C =δ2; The C -U A =δ3; If δ1∈D, δ2∈D and δ3∈D, the data is normal and the process returns to step S10, otherwise the phase line abnormality information is sent to the control module; Where: D = [d1, d2], d1 is the minimum allowable difference between phase voltages, d2 is the maximum allowable difference between phase voltages; D is the allowable fluctuation range of the phase voltage difference.

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