Intelligent alarm device and method for monitoring open circuit of secondary circuit of running current transformer

Abstract

The invention provides an intelligent alarm device for monitoring an open circuit of a secondary circuit of a running current transformer, which is used on the secondary circuit led out from a current transformer body and comprises four current collectors with polarity directions and an alarm. The four current collectors have the same polarity setting corresponding to the secondary circuit, and collect the current magnitude and direction of the A-phase line, the B-phase line, the C-phase line and the N-phase line on the secondary circuit in real time; the alarm receives the magnitude and the direction of the current collected by the four current collectors, judges whether at least one of the A phase line, the B phase line, the C phase line and the N phase line of the secondary circuit has an open circuit or not according to the pre-stored phase line conditions of the corresponding four current collectors connected to the secondary circuit, and gives an alarm when at least one of the A phase line, the B phase line, the C phase line and the N phase line is judged to have the open circuit. According to the invention, the problem that the open circuit condition of the secondary circuit of the current transformer cannot be monitored in the electrified mode in the prior art is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of power systems, and in particular to an intelligent alarm device and method for monitoring the open circuit of a secondary circuit of a running current transformer. Background Art

[0002] The current transformer first uses the principle of electromagnetic induction to convert the primary large current into the secondary small current, and then introduces the secondary current into the corresponding device through the secondary circuit wiring, providing information data for various protection, metering, recording and other devices based on the current principle in the plant (station), thereby realizing the current data collection of each component in the station. Figure 1 As shown, the current transformer is divided into a primary part and a secondary part. The secondary part is led out through four wires A, B, C, and N respectively, and connected to the protection device through the terminal box.

[0003] At present, with the increase in substations and power plants, the secondary circuit of current transformers may open due to reasons such as long connection distance, loose wiring and aging equipment, resulting in high voltage damage to equipment, even endangering personnel safety and incorrect protection operation.

[0004] However, the existing technology for detecting the open circuit condition of the secondary circuit of the current transformer requires power outage, resulting in a lack of monitoring the open circuit condition of the secondary circuit of the current transformer in the live mode. Therefore, it is necessary to provide a device and method for monitoring the open circuit condition of the secondary circuit of the current transformer in the live mode. Summary of the Invention

[0005] The technical problem to be solved by the embodiments of the present invention is to provide an intelligent alarm device and method for monitoring the open circuit of the secondary circuit of a running current transformer, thereby solving the problem in the prior art that the open circuit of the secondary circuit of the current transformer cannot be monitored in the energized mode.

[0006] In order to solve the above technical problems, an embodiment of the present invention provides an intelligent alarm device for monitoring the open circuit of the secondary circuit of a running current transformer, which is used on the secondary circuit derived from the current transformer body and includes four current collectors with polarity directions and an alarm; wherein,

[0007] One end of the four current collectors is respectively mounted on the A phase line, the B phase line, the C phase line and the N phase line of the secondary circuit and the polarity is set in the same direction, and the other end is connected to the alarm device, and is used to collect the current magnitude and direction of the A phase line, the B phase line, the C phase line and the N phase line of the secondary circuit in real time;

[0008] The alarm is used to receive the current magnitude and direction collected by the four current collectors, and combined with the pre-stored phase line conditions corresponding to the four current collectors connected to the secondary circuit, determine whether at least one of the A phase line, B phase line, C phase line and N phase line of the secondary circuit has an open circuit, and when it is determined that at least one has an open circuit, an alarm is issued.

[0009] The polarity directions of the four current collectors are all set to face the current transformer body.

[0010] The alarm device includes a receiving unit, a pre-storage unit, a judgment unit and an alarm unit; wherein,

[0011] One end of the receiving unit is connected to the four current collectors, and the other end is connected to an input end of the judging unit, for receiving the magnitude and direction of the current collected by the four current collectors;

[0012] The pre-storage unit is used to pre-store the phase line conditions of the four current collectors connected to the secondary circuit respectively;

[0013] The other input end of the judgment unit is connected to the pre-storage unit, and the output end is connected to the alarm unit, and is used to judge whether at least one of the phase A line, the phase B line, the phase C line, and the phase N line on the secondary circuit is open according to the magnitude and direction of the current collected by the four current collectors and in combination with the phase line conditions of the four current collectors respectively connected to the secondary circuit, and when it is determined that at least one of the phase A line, the phase B line, the phase C line, and the phase N line on the secondary circuit is open, generate an alarm signal and send it to the alarm unit;

[0014] The alarm unit is used to issue an alarm when receiving the alarm signal output by the judgment unit.

[0015] Wherein, the judgment unit includes a first judgment module, a second judgment module and a signal sending module; wherein,

[0016] The first judgment module is configured to determine that none of the four phases A, B, C, and N on the secondary circuit are open circuits, and not generate an alarm signal, when it is determined that the currents of the three phases A, B, and C on the secondary circuit are equal and greater than the current of the corresponding N phase, and that the currents of the three phases A, B, and C on the secondary circuit are in the same direction and opposite to the current direction of the corresponding N phase;

[0017] The second judgment module is configured to determine that at least one of the four phase lines A, B, C and N on the secondary circuit is open when it is determined that the current magnitudes of the three phase lines A, B and C on the secondary circuit are unbalanced or zero; and / or when it is determined that the current magnitude of the N phase on the secondary circuit is zero; and / or when it is determined that the current direction of the N phase on the secondary circuit is the same as the current direction of at least one of the corresponding phase lines A, B and C, and to generate an alarm signal;

[0018] The signal sending module is used to send the alarm signal to the alarm unit.

[0019] Wherein, the alarm unit is formed by a sound alarm circuit and / or a light alarm circuit.

[0020] An embodiment of the present invention further provides an intelligent alarm method for monitoring an open circuit in the secondary circuit of a running current transformer, which is implemented on the aforementioned intelligent alarm device for monitoring an open circuit in the secondary circuit of a running current transformer. The method comprises the following steps:

[0021] Four current collectors collect the current magnitude and direction of the A-phase, B-phase, C-phase and N-phase lines on the secondary circuit derived from the current transformer in real time;

[0022] The alarm receives the current magnitude and direction collected by the four current collectors, and combines the pre-stored phase line conditions corresponding to the four current collectors connected to the secondary circuit to determine whether at least one of the A phase line, B phase line, C phase line and N phase line of the secondary circuit is open, and when it is determined that at least one is open, an alarm is issued.

[0023] The alarm receives the current magnitude and direction collected by the four current collectors, and combines the pre-stored phase line conditions corresponding to the four current collectors connected to the secondary circuit to determine whether at least one of the A phase line, B phase line, C phase line and N phase line of the secondary circuit has an open circuit. When it is determined that at least one of the phase lines is open, the specific steps of issuing an alarm include:

[0024] When the alarm device determines that the currents of the three phases A, B, and C on the secondary circuit are equal in magnitude and greater than the current of the corresponding N phase, and that the currents of the three phases A, B, and C on the secondary circuit are in the same direction and opposite to the current direction of the corresponding N phase, it determines that none of the four phases A, B, C, and N on the secondary circuit are open circuits, and no alarm signal is generated;

[0025] When the alarm device determines that the current magnitudes of the A-phase line, the B-phase line and the C-phase line on the secondary circuit are unbalanced or are 0; and / or when the alarm device determines that the current magnitude of the N-phase line on the secondary circuit is 0; and / or when the alarm device determines that the current direction of the N-phase line on the secondary circuit is the same as the current direction of at least one of the corresponding A-phase line, the B-phase line and the C-phase line, it determines that at least one of the A-phase line, the B-phase line, the C-phase line and the N-phase line on the secondary circuit has an open circuit and generates an alarm signal.

[0026] The specific steps of determining that at least one of the four phases A, B, C and N on the secondary circuit is open and generating an alarm signal when the alarm device determines that the current magnitudes of the three phases A, B and C on the secondary circuit are unbalanced or zero; and / or when the current magnitude of the N phase on the secondary circuit is zero; and / or when the current direction of the N phase on the secondary circuit is the same as the current direction of at least one of the corresponding phases A, B and C, include:

[0027] When the alarm device determines that the currents of the three phase lines A, B and C on the secondary circuit are unbalanced or zero, it determines that at least one of the three phase lines A, B and C on the secondary circuit is open and generates an alarm signal;

[0028] When the alarm device determines that the current of the N-phase line on the secondary circuit is 0, it determines that there is an open circuit in the N-phase line on the secondary circuit and generates an alarm signal;

[0029] When the alarm device determines that the current direction of the N phase line on the secondary circuit is the same as the current direction of at least one of the corresponding A phase line, B phase line and C phase line, it determines that there is an open circuit in the phase line on the secondary circuit with the same current direction as the N phase line, and generates an alarm signal.

[0030] The implementation of the embodiments of the present invention has the following beneficial effects:

[0031] The present invention uses four current collectors to collect the current magnitudes and directions of the A-phase line, the B-phase line, the C-phase line and the N-phase line on the secondary circuit led out of the current transformer body in real time. On the alarm device, based on the current magnitudes and directions collected by the four current collectors and combined with the pre-stored phase line conditions of the four current collectors connected to the secondary circuit, it is judged whether at least one of the A-phase line, the B-phase line, the C-phase line and the N-phase line of the secondary circuit is open. If at least one of them is open, an alarm is automatically issued, thereby solving the problem in the prior art that it is impossible to monitor the open circuit condition of the secondary circuit of the current transformer in the energized mode. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, without paying any creative work, other drawings obtained based on these drawings still fall within the scope of the present invention.

[0033] Figure 1 This is a schematic diagram of the structure of a three-phase four-wire access protection device for the secondary winding of a current transformer in the prior art;

[0034] Figure 2 This is a structural diagram of an intelligent alarm device for monitoring an open circuit in the secondary circuit of a running current transformer provided in an embodiment of the present invention, connected to the secondary circuit of the current transformer;

[0035] Figure 3 A schematic diagram of the structure of an alarm in an intelligent alarm device for monitoring the secondary circuit open of a running current transformer provided in an embodiment of the present invention

[0036] Figure 4 The present invention provides a flowchart of an intelligent alarm method for monitoring an open circuit in the secondary circuit of a running current transformer. DETAILED DESCRIPTION

[0037] In order to make the objectives, technical solutions and advantages of the present invention more clear, the present invention will be described in further detail below with reference to the accompanying drawings.

[0038] like Figure 2 and Figure 3 As shown in the figure, an intelligent alarm device for monitoring the open circuit of the secondary circuit of the running current transformer is proposed in an embodiment of the present invention, which is used on the secondary circuit led out of the current transformer body, including four current collectors 1 with polarity directions and an alarm 2; wherein,

[0039] One end of the four current collectors 1 is respectively mounted on the A phase line, B phase line, C phase line and N phase line of the secondary circuit and the polarity is set in the same direction (such as towards the current transformer body at the same time), and the other end is connected to the alarm 2, which is used to collect the current magnitude and direction of the A phase line, B phase line, C phase line and N phase line of the secondary circuit in real time;

[0040] Alarm device 2 is used to receive the magnitude and direction of the current collected by the four current collectors 1 and, in combination with the pre-stored phase line conditions corresponding to the four current collectors 1 connected to the secondary circuit, determine whether at least one of the secondary circuit's phase lines A, B, C, and N is open circuit, and issue an alarm if at least one is determined to be open circuit. It should be noted that the phase line conditions of the four current collectors 1 connected to the secondary circuit are pre-stored on alarm device 2 based on the actual conditions of the four current collectors 1 being installed on the secondary circuit's phase lines A, B, C, and N, so that the alarm device 2 can subsequently quickly identify the phase lines where the four current collectors 1 are collecting the secondary circuit current.

[0041] In the embodiment of the present invention, the alarm device 2 includes a receiving unit 21, a pre-storage unit 22, a judgment unit 23 and an alarm unit 24; wherein,

[0042] One end of the receiving unit 21 is connected to the four current collectors 1, and the other end is connected to an input end of the judging unit 23, for receiving the current magnitude and direction collected by the four current collectors 1;

[0043] The pre-storage unit 22 is used to pre-store the phase line conditions of the four current collectors 1 connected to the secondary circuit respectively;

[0044] The other input end of the judgment unit 23 is connected to the pre-storage unit 22, and the output end is connected to the alarm unit 24. The judgment unit 23 is used to judge whether at least one of the phase lines A, B, C, and N on the secondary circuit is open-circuited based on the magnitude and direction of the current collected by the four current collectors 1 and the phase line conditions of the four current collectors 1 connected to the secondary circuit. When it is determined that at least one of the phase lines A, B, C, and N on the secondary circuit is open-circuited, an alarm signal is generated and sent to the alarm unit 24.

[0045] The alarm unit 24 is formed by a sound alarm circuit and / or a light alarm circuit, and is used to issue an alarm when receiving the alarm signal output by the judgment unit.

[0046] In the embodiment of the present invention, the judgment unit 23 includes a first judgment module 231, a second judgment module 232 and a signal sending module 233; wherein,

[0047] The first judgment module 231 is configured to determine that none of the four phases A, B, C, and N on the secondary circuit are open circuits, and not generate an alarm signal, when it is determined that the currents of the three phases A, B, C, and N on the secondary circuit are equal and greater than the current of the corresponding phase N, and that the currents of the three phases A, B, C, and N on the secondary circuit are in the same direction and opposite to the current of the corresponding phase N.

[0048] The second judgment module 232 is configured to determine that at least one of the four phases A, B, C, and N on the secondary circuit is open when it is determined that the currents of the three phases A, B, and C on the secondary circuit are unbalanced or zero; and / or when it is determined that the current of the N phase on the secondary circuit is zero; and / or when it is determined that the current direction of the N phase on the secondary circuit is the same as the current direction of at least one of the corresponding phases A, B, and C, and to generate an alarm signal;

[0049] The signal sending module 233 is configured to send an alarm signal to the alarm unit 24 .

[0050] In one example, when the second determination module 232 determines that the currents of phase A, phase B, and phase C on the secondary circuit are unbalanced or zero, it determines that at least one of the phase A, phase B, and phase C on the secondary circuit is open and generates an alarm signal.

[0051] For example, if the currents of phase A and phase B are equal and greater than the current of phase C, then there is an open circuit in phase C; for another example, if the currents of phase B and phase C are equal and greater than the current of phase A, then there is an open circuit in phase A; for another example, if the currents of phase A, phase B and phase C are all 0, then there are open circuits in phase A, phase B and phase C; for another example, if the current of phase B is 0, then there is an open circuit in phase B.

[0052] In another example, when the second determination module 232 determines that the current of the N-phase line on the secondary circuit is 0, it determines that there is an open circuit in the N-phase line on the secondary circuit and generates an alarm signal.

[0053] In another example, when the second judgment module 232 determines that the current direction of the N-phase line on the secondary circuit is the same as the current direction of at least one of the corresponding A-phase line, B-phase line, and C-phase line, it determines that there is an open circuit in the phase line on the secondary circuit with the same current direction as the N-phase line, and generates an alarm signal.

[0054] For example, if the current direction of the N phase line is the same as that of the A phase line, then there is an open circuit in the A phase line; for another example, if the current direction of the N phase line is the same as that of the A phase line and the C phase line, then there are open circuits in both the A phase line and the C phase line.

[0055] like Figure 4 As shown in FIG, an intelligent alarm method for monitoring an open circuit of a secondary circuit of a running current transformer is provided in an embodiment of the present invention. The method is implemented on an intelligent alarm device for monitoring an open circuit of a secondary circuit of a running current transformer provided in an embodiment of the present invention. The method includes the following steps:

[0056] Step S1: Four current collectors collect the current magnitude and direction of the A-phase line, the B-phase line, the C-phase line, and the N-phase line on the secondary circuit led out of the current transformer body in real time;

[0057] Step S2: The alarm receives the current magnitude and direction collected by the four current collectors, and combines the pre-stored phase line conditions corresponding to the four current collectors connected to the secondary circuit to determine whether at least one of the A phase line, B phase line, C phase line and N phase line of the secondary circuit has an open circuit, and issues an alarm when it is determined that at least one has an open circuit.

[0058] The specific process is that in step S1, after the four current collectors are correspondingly installed on the A-phase line, B-phase line, C-phase line and N-phase line of the secondary circuit led out from the current transformer body and the polarities are set in the same direction (such as simultaneously facing the current transformer body), the current magnitude and direction of the A-phase line, B-phase line, C-phase line and N-phase line on the secondary circuit collected in real time by the four current collectors are obtained.

[0059] In step S2, first, the alarm receives the current magnitude and direction collected by the four current collectors.

[0060] Secondly, the alarm device extracts the pre-stored phase line conditions corresponding to the four current collectors connected to the secondary circuit. When it is determined that the currents of the three phase lines A, B and C on the secondary circuit are equal and greater than the current of the corresponding N phase line, and that the current directions of the three phase lines A, B and C on the secondary circuit are the same and opposite to the current direction of the corresponding N phase line, it is determined that there is no open circuit in the four phase lines A, B, C and N on the secondary circuit, and no alarm signal is generated.

[0061] Also, when it is determined that the current magnitudes of the A-phase line, the B-phase line, and the C-phase line on the secondary circuit are unbalanced or are 0; and / or, when it is determined that the current magnitude of the N-phase line on the secondary circuit is 0; and / or, when it is determined that the current direction of the N-phase line on the secondary circuit is the same as the current direction of at least one of the corresponding A-phase line, the B-phase line, and the C-phase line, it is determined that at least one of the A-phase line, the B-phase line, the C-phase line, and the N-phase line on the secondary circuit is open, and an alarm signal is generated.

[0062] For example, when the alarm device determines that the currents of phase A, phase B and phase C on the secondary circuit are unbalanced or zero, it determines that at least one of the phase A, phase B and phase C on the secondary circuit is open and generates an alarm signal.

[0063] For another example, when the alarm device determines that the current of the N-phase line on the secondary circuit is 0, it determines that there is an open circuit in the N-phase line on the secondary circuit and generates an alarm signal.

[0064] For example, when the alarm device determines that the current direction of the N phase line on the secondary circuit is the same as the current direction of at least one of the corresponding A phase line, B phase line and C phase line, it determines that there is an open circuit in the phase line on the secondary circuit with the same current direction as the N phase line, and generates an alarm signal.

[0065] The implementation of the embodiments of the present invention has the following beneficial effects:

[0066] The present invention uses four current collectors to collect the current magnitudes and directions of the A-phase line, the B-phase line, the C-phase line and the N-phase line on the secondary circuit led out of the current transformer body in real time. On the alarm device, based on the current magnitudes and directions collected by the four current collectors and combined with the pre-stored phase line conditions of the four current collectors connected to the secondary circuit, it is judged whether at least one of the A-phase line, the B-phase line, the C-phase line and the N-phase line of the secondary circuit is open. If at least one of them is open, an alarm is automatically issued, thereby solving the problem in the prior art that it is impossible to monitor the open circuit condition of the secondary circuit of the current transformer in the energized mode.

[0067] It is worth noting that in the above-mentioned device embodiment, the various device units included are only divided according to functional logic, but are not limited to the above-mentioned division, as long as the corresponding functions can be realized; in addition, the specific names of the various functional units are only for the convenience of distinguishing each other, and are not used to limit the scope of protection of the present invention.

[0068] The above disclosure is merely a preferred embodiment of the present invention and certainly cannot be used to limit the scope of the present invention. Therefore, equivalent changes made according to the claims of the present invention are still within the scope of the present invention.

Claims

1. An intelligent alarm device for monitoring the open circuit of the secondary circuit of a running current transformer, used on the secondary circuit derived from the current transformer body, characterized in that: It includes four current collectors with polarity directions and an alarm; among them, One end of the four current collectors is respectively mounted on the A phase line, the B phase line, the C phase line and the N phase line of the secondary circuit and the polarity is set in the same direction, and the other end is connected to the alarm device, and is used to collect the current magnitude and direction of the A phase line, the B phase line, the C phase line and the N phase line of the secondary circuit in real time; The alarm is used to receive the current magnitude and direction collected by the four current collectors, and combined with the pre-stored phase line conditions corresponding to the four current collectors connected to the secondary circuit, determine whether at least one of the A phase line, B phase line, C phase line and N phase line of the secondary circuit has an open circuit, and when it is determined that at least one has an open circuit, an alarm is issued.

2. The intelligent alarm device for monitoring the secondary circuit open of the operating current transformer according to claim 1, characterized in that: The polarity directions of the four current collectors are all set to face the current transformer body.

3. The intelligent alarm device for monitoring the secondary circuit open of the operating current transformer according to claim 1, characterized in that: The alarm device includes a receiving unit, a pre-storage unit, a judgment unit and an alarm unit; wherein, One end of the receiving unit is connected to the four current collectors, and the other end is connected to an input end of the judging unit, for receiving the magnitude and direction of the current collected by the four current collectors; The pre-storage unit is used to pre-store the phase line conditions of the four current collectors connected to the secondary circuit respectively; The other input end of the judgment unit is connected to the pre-storage unit, and the output end is connected to the alarm unit, and is used to judge whether at least one of the phase A line, the phase B line, the phase C line, and the phase N line on the secondary circuit is open according to the magnitude and direction of the current collected by the four current collectors and in combination with the phase line conditions of the four current collectors respectively connected to the secondary circuit, and when it is determined that at least one of the phase A line, the phase B line, the phase C line, and the phase N line on the secondary circuit is open, generate an alarm signal and send it to the alarm unit; The alarm unit is used to issue an alarm when receiving the alarm signal output by the judgment unit.

4. The intelligent alarm device for monitoring the secondary circuit open of the operating current transformer according to claim 3, characterized in that: The judgment unit includes a first judgment module, a second judgment module and a signal sending module; wherein, The first judgment module is configured to determine that none of the four phases A, B, C, and N on the secondary circuit are open circuits, and not generate an alarm signal, when it is determined that the currents of the three phases A, B, and C on the secondary circuit are equal and greater than the current of the corresponding N phase, and that the currents of the three phases A, B, and C on the secondary circuit are in the same direction and opposite to the current direction of the corresponding N phase; The second judgment module is configured to determine that at least one of the four phase lines A, B, C and N on the secondary circuit is open when it is determined that the current magnitudes of the three phase lines A, B and C on the secondary circuit are unbalanced or zero; and / or when it is determined that the current magnitude of the N phase on the secondary circuit is zero; and / or when it is determined that the current direction of the N phase on the secondary circuit is the same as the current direction of at least one of the corresponding phase lines A, B and C, and to generate an alarm signal; The signal sending module is used to send the alarm signal to the alarm unit.

5. The intelligent alarm device for monitoring the secondary circuit open of the operating current transformer according to claim 4, characterized in that: The alarm unit is formed by a sound alarm circuit and / or a light alarm circuit.

6. An intelligent alarm method for monitoring the open circuit of the secondary circuit of a running current transformer, characterized in that: It is implemented on the intelligent alarm device for monitoring the secondary circuit open of the operating current transformer as claimed in claim 5, and the method The following steps are involved: Four current collectors collect the current magnitude and direction of the A-phase, B-phase, C-phase and N-phase lines on the secondary circuit derived from the current transformer in real time; The alarm receives the current magnitude and direction collected by the four current collectors, and combines the pre-stored phase line conditions corresponding to the four current collectors connected to the secondary circuit to determine whether at least one of the A phase line, B phase line, C phase line and N phase line of the secondary circuit is open, and when it is determined that at least one is open, an alarm is issued.

7. The intelligent alarm method for monitoring the secondary circuit open of a current transformer according to claim 6, characterized in that: The alarm receives the magnitude and direction of the current collected by the four current collectors, and combines the pre-stored phase line conditions corresponding to the four current collectors connected to the secondary circuit to determine whether at least one of the A phase line, the B phase line, the C phase line, and the N phase line of the secondary circuit has an open circuit. When it is determined that at least one of the phase lines is open, the specific steps of issuing an alarm include: When the alarm device determines that the currents of the three phases A, B, and C on the secondary circuit are equal in magnitude and greater than the current of the corresponding N phase, and that the currents of the three phases A, B, and C on the secondary circuit are in the same direction and opposite to the current direction of the corresponding N phase, it determines that none of the four phases A, B, C, and N on the secondary circuit are open circuits, and no alarm signal is generated; When the alarm device determines that the current magnitudes of the A-phase line, the B-phase line and the C-phase line on the secondary circuit are unbalanced or are 0; and / or when the alarm device determines that the current magnitude of the N-phase line on the secondary circuit is 0; and / or when the alarm device determines that the current direction of the N-phase line on the secondary circuit is the same as the current direction of at least one of the corresponding A-phase line, the B-phase line and the C-phase line, it determines that at least one of the A-phase line, the B-phase line, the C-phase line and the N-phase line on the secondary circuit has an open circuit and generates an alarm signal.

8. The intelligent alarm method for monitoring the secondary circuit open of a current transformer according to claim 7, characterized in that: The specific steps of determining that at least one of the four phases A, B, C and N on the secondary circuit is open and generating an alarm signal when the alarm device determines that the current magnitudes of the three phases A, B and C on the secondary circuit are unbalanced or zero; and / or when the alarm device determines that the current magnitude of the N phase on the secondary circuit is zero; and / or when the alarm device determines that the current direction of the N phase on the secondary circuit is the same as the current direction of at least one of the corresponding phases A, B and C, and generates an alarm signal include: When the alarm device determines that the currents of the three phase lines A, B and C on the secondary circuit are unbalanced or zero, it determines that at least one of the three phase lines A, B and C on the secondary circuit is open and generates an alarm signal; When the alarm device determines that the current of the N-phase line on the secondary circuit is 0, it determines that there is an open circuit in the N-phase line on the secondary circuit and generates an alarm signal; When the alarm device determines that the current direction of the N phase line on the secondary circuit is the same as the current direction of at least one of the corresponding A phase line, B phase line and C phase line, it determines that there is an open circuit in the phase line on the secondary circuit with the same current direction as the N phase line, and generates an alarm signal.

Images