CN211718492U - TN system fault detection circuit - Google Patents
TN system fault detection circuit Download PDFInfo
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- CN211718492U CN211718492U CN202020038806.0U CN202020038806U CN211718492U CN 211718492 U CN211718492 U CN 211718492U CN 202020038806 U CN202020038806 U CN 202020038806U CN 211718492 U CN211718492 U CN 211718492U
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Abstract
The application discloses a TN system fault detection circuit, which comprises electrical equipment and electric equipment; an L-phase line and an N-neutral line are arranged between the electrical equipment and the electric equipment for connection, and the electrical equipment is connected with the ground through a ground wire; the TN system fault detection circuit further comprises a first component and a second component; one end of the first component is connected with the L-phase line, the other end of the first component is connected with one end of the second component and the grounding point of the electrical equipment, and the other end of the second component is connected with the N-neutral line. According to the method, a neutral point connected with the grounding point of the electrical equipment is constructed through the first component and the second component, and faults that a grounding wire is not connected into the neutral point and faults that an L-phase wire and an N-phase wire are reversely connected can be detected and judged according to voltages at two ends of the first component and the second component; the personal safety of the user of the electrical equipment is ensured.
Description
Technical Field
The application relates to the technical field of power electronics, in particular to a fault detection circuit of a TN system.
Background
TN systems, called protection zero-crossings. When the metal casing of the electrical equipment is electrified due to a fault, a phase line and a zero line are in short circuit, the loop resistance is small, the current is large, and the fuse wire can be quickly fused or the protection device acts to cut off the power supply.
As shown in fig. 1, in the conventional single-phase TN system, an L-line series switch K1 is generally used, an N-line is directly connected to an electrical device, and the electrical device is connected to the ground through a ground line; if the L line and the N line are reversely connected, even if the switch K1 is turned off, the electrical equipment is still electrified, which may cause electrical damage to maintenance personnel.
SUMMERY OF THE UTILITY MODEL
In view of the above, the present application is directed to a TN system fault detection circuit, so as to solve how to identify a power line of an electrical device in a TN system.
The technical scheme adopted by the application for solving the technical problems is as follows:
according to one aspect of the application, a TN system fault detection circuit is provided, which includes an electrical device and an electric device; an L-phase line and an N-neutral line are arranged between the electrical equipment and the electric equipment for connection, and the electrical equipment is connected with the ground through a ground wire; the TN system fault detection circuit further comprises a first component and a second component;
one end of the first component is connected with the L-phase line, the other end of the first component is connected with one end of the second component and the grounding point of the electrical equipment, and the other end of the second component is connected with the N-neutral line.
According to the fault detection circuit of the TN system, the neutral point connected with the grounding point of the electrical equipment is constructed through the first component and the second component, and faults that a grounding wire is not connected into, and an L-phase wire and an N-phase wire are reversely connected can be detected and judged according to voltages at two ends of the first component and the second component; the personal safety of the user of the electrical equipment is ensured.
Drawings
Fig. 1 is a schematic structural diagram of a fault detection circuit of a conventional TN system;
fig. 2 is a schematic structural diagram of a fault detection circuit of a TN system according to an embodiment of the present application;
fig. 3 is a schematic structural diagram of a specific example of a TN system fault detection circuit according to an embodiment of the present application;
fig. 4 is a schematic flow chart of a TN system fault detection method according to an embodiment of the present application.
The implementation, functional features and advantages of the objectives of the present application will be further explained with reference to the accompanying drawings.
Detailed Description
In order to make the technical problems, technical solutions and advantageous effects to be solved by the present application clearer and clearer, the present application is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present application and are not intended to limit the present application.
In the description of the present application, it is to be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", and the like, indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, are only for convenience in describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed in a specific orientation, and be operated, and thus, should not be construed as limiting the present application. Furthermore, the terms "first" and "second" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.
As shown in fig. 2, an embodiment of the present application provides a TN system fault detection circuit, where the TN system fault detection circuit includes an electrical device and an electrical device (shown as AC in the figure); an L-phase line and an N-neutral line are arranged between the electrical equipment and the electric equipment for connection, and the electrical equipment is connected with the ground through a ground wire; the TN system fault detection circuit further comprises a first component Z1 and a second component Z2;
one end of the first component Z1 is connected to the L-phase line, the other end of the first component Z1 is connected to one end of the second component Z2 and to the grounding point of the electrical equipment, and the other end of the second component Z2 is connected to the N-neutral line.
In the present exemplary embodiment, the neutral point O, which is formed by the first component Z1 and the second component Z2, is connected to the ground point of the electrical device.
In this embodiment, the first component Z1 and the second component Z2 may be any combination of a resistor, an inductor, a capacitor, and the combination of the three, and are not limited herein.
In this embodiment, the TN system fault detection circuit further includes a switch K1 connected in series in the L-phase line.
In one embodiment, the TN system fault detection circuit further comprises a first voltage sampling circuit and a second voltage sampling circuit;
the first voltage sampling circuit is used for sampling the voltage of the two ends of the first component Z1, and the second voltage sampling circuit is used for sampling the voltage of the two ends of the second component Z2; or
The first voltage sampling circuit is used for sampling the voltage at two ends of the first component Z1, and the second voltage sampling circuit is used for sampling the voltage between the L-phase line and the N-neutral line; or
The first voltage sampling circuit is used for sampling the voltage at two ends of the second component Z2, and the second voltage sampling circuit is used for sampling the voltage between the L-phase line and the N-neutral line.
In this embodiment, the voltages at the two ends of the first component Z1 and the second component Z2 can be determined by the first voltage sampling circuit and the second voltage sampling circuit, and then the fault that the ground line is not connected and the L-phase line and the N-phase line are reversely connected can be detected and judged according to the voltages at the two ends of the first component and the second component.
To better illustrate the embodiments of the present application, the following description is made with reference to fig. 3:
as shown in fig. 3, the first component Z1 and the second component Z2 select two high resistance resistors R with equal resistance, the voltage across the first component Z1 is denoted as U1, the voltage across the second component Z2 is denoted as U2, and the voltage between the L-phase line and the N-neutral line is denoted as U3. Any two voltages of U1, U2 and U3 are sampled, and the other voltage can be determined.
The fault judgment process of the circuit is as follows:
firstly, if the grounding wire is not connected, U1 is approximately equal to U2, and the equipment prompts the fault information that the grounding wire is not connected. And (4) not carrying out the next judgment until the grounding wire is connected.
Secondly, under the condition that the grounding wire is connected, if the L-phase wire and the N-neutral wire are normally connected, the U1 ≈ U3, and the U2 ≈ 0.
If the L-phase line and the N-neutral line are reversely connected, U1 is approximately equal to 0, U2 is approximately equal to U3, and the equipment prompts fault information of the reversely connected L-phase line and the N-neutral line.
According to the fault detection circuit of the TN system, the neutral point connected with the grounding point of the electrical equipment is constructed through the first component and the second component, and faults that a grounding wire is not connected into, and an L-phase wire and an N-phase wire are reversely connected can be detected and judged according to voltages at two ends of the first component and the second component; the personal safety of the user of the electrical equipment is ensured.
As shown in fig. 4, another embodiment of the present application provides a method for detecting a fault of a TN system, and a fault detection circuit of the TN system may refer to the foregoing embodiments, which are not described herein again.
The TN system fault detection method includes:
step S11, determining the voltage at two ends of the first component and the voltage at two ends of the second component;
step S12, judging whether the absolute value of the difference value between the voltage at the two ends of the first component and the voltage at the two ends of the second component is smaller than a first preset value;
and step S13, prompting the fault information that the grounding wire is not connected when the absolute value of the difference value between the voltage at the two ends of the first component and the voltage at the two ends of the second component is smaller than a first preset value.
In one embodiment, the determining whether an absolute value of a difference between a voltage across the first component and a voltage across the second component is smaller than a first preset value further includes:
determining the voltage between the L-phase line and the N-neutral line under the condition that the absolute value of the difference value between the voltage at the two ends of the first component and the voltage at the two ends of the second component is not smaller than a first preset value;
judging whether the voltage at two ends of the first component is smaller than a second preset value or not, and whether the absolute value of the difference value between the voltage at two ends of the second component and the voltage between the L-phase line and the N-middle line is smaller than a third preset value or not;
and prompting fault information of reversely connecting the L-phase line and the N-neutral line under the condition that the voltage at two ends of the first component is smaller than a second preset value and the absolute value of the difference value between the voltage at two ends of the second component and the voltage between the L-phase line and the N-neutral line is smaller than a third preset value.
According to the fault detection method of the TN system, the neutral point connected with the grounding point of the electrical equipment is constructed through the first component and the second component, and faults that a grounding line is not connected into and L-phase lines and N-phase lines are reversely connected can be detected and judged according to voltages at two ends of the first component and the second component; the personal safety of the user of the electrical equipment is ensured.
The preferred embodiments of the present application have been described above with reference to the accompanying drawings, and are not intended to limit the scope of the claims of the application accordingly. Any modifications, equivalents and improvements which may occur to those skilled in the art without departing from the scope and spirit of the present application are intended to be within the scope of the claims of the present application.
Claims (4)
1. A TN system fault detection circuit comprises electrical equipment and electric equipment; an L-phase line and an N-neutral line are arranged between the electrical equipment and the electric equipment for connection, and the electrical equipment is connected with the ground through a ground wire; the TN system fault detection circuit is characterized by also comprising a first component and a second component;
one end of the first component is connected with the L-phase line, the other end of the first component is connected with one end of the second component and the grounding point of the electrical equipment, and the other end of the second component is connected with the N-neutral line.
2. The TN system fault detection circuit of claim 1, wherein the first component and the second component comprise one of a resistor, an inductor, and a capacitor.
3. The TN system fault detection circuit of claim 1, wherein the TN system fault detection circuit further includes a switch connected in series in the L-phase line.
4. The TN system fault detection circuit of claim 1, wherein the TN system fault detection circuit further includes a first voltage sampling circuit and a second voltage sampling circuit;
the first voltage sampling circuit is used for sampling the voltage at two ends of the first component, and the second voltage sampling circuit is used for sampling the voltage at two ends of the second component; or
The first voltage sampling circuit is used for sampling voltages at two ends of the first component, and the second voltage sampling circuit is used for sampling voltages between the L-phase line and the N-neutral line; or
The first voltage sampling circuit is used for sampling the voltage at two ends of the second component, and the second voltage sampling circuit is used for sampling the voltage between the L-phase line and the N-neutral line.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202020038806.0U CN211718492U (en) | 2020-01-09 | 2020-01-09 | TN system fault detection circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202020038806.0U CN211718492U (en) | 2020-01-09 | 2020-01-09 | TN system fault detection circuit |
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| Publication Number | Publication Date |
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| CN211718492U true CN211718492U (en) | 2020-10-20 |
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| CN202020038806.0U Active CN211718492U (en) | 2020-01-09 | 2020-01-09 | TN system fault detection circuit |
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