CN217642693U

CN217642693U - Protective grounding protection device

Info

Publication number: CN217642693U
Application number: CN202221825676.0U
Authority: CN
Inventors: 冯敏杰; 邓北玲
Original assignee: Xi'an Apt Power Technology Co ltd
Current assignee: Xi'an Apt Power Technology Co ltd
Priority date: 2022-07-14
Filing date: 2022-07-14
Publication date: 2022-10-21
Anticipated expiration: 2032-07-14

Abstract

The utility model discloses a protection ground protection device, include: the voltage detection unit is used for detecting the voltage between the metal shell and the grounding electrode, and when the detected voltage exceeds a set threshold value, the voltage detection unit generates a trigger signal; and the intermediate relay is provided with a normally closed contact which is used for being connected in series in a breaker closing circuit of the main circuit, and when the intermediate relay receives a trigger signal, the normally closed contact is opened to control the main circuit to be powered off. The utility model discloses a to the real-time measurement to ground voltage of equipment metal casing to safe voltage triggers the main loop circuit breaker as the threshold value, thereby forms the protection of new one deck to protection ground connection.

Description

Protective grounding protection device

Technical Field

The utility model relates to a power electronics technical field, in particular to protection ground protection device.

Background

The protective grounding is commonly formed by shell grounding and is widely adopted in an electrical system, and the effectiveness of protective grounding protection does not need to be questioned. The grounding is simply an electrical connection between an electrical device and the ground. The grounding device comprises a grounding terminal, a grounding wire, a grounding electrode/grounding pile and a grounding grid on the electrical equipment. In practical application, the grounding terminal and the grounding pile may be in cold joint or fall off, and the connection between the grounding wire and the grounding terminal and the grounding pile may also be loosened in the power utilization process to cause grounding failure. Under these circumstances, the ground protection does not function as an electric shock protection.

Because the grounding terminal and the grounding wire on the electrical equipment are connected in series with the grounding electrode/grounding pile and the grounding grid, the current grounding protection has the greatest defect of poor reliability. Once a link has a problem, the protection grounding fails. In addition, an electric shock protector can be selected in the market, seems to make up the deficiency of ground protection, but also has the deficiency. The mechanism of the electric shock protector is to detect and control zero sequence current, and the zero sequence current can trip only when leakage current or personnel electric shock accident occurs between the phase line and the ground and the zero sequence current reaches the current setting value of the electric shock protector. The degree of injury of human body electric shock depends on the magnitude of current flowing through the human body, and is divided into sensing current, breaking current and fatal current. If the trigger current of the electric shock protector is not properly set or the sensitivity of the electric shock protector is not enough, the zero sequence current can get rid of the current and even the fatal current, and the consequence is unimaginable. And after the protection grounding fails, the potential of the electric shell immediately rises to the phase voltage, zero-sequence current does not change obviously as long as no human body is electrified, but hidden danger already appears, the hidden danger is not eliminated and eliminated by an electric shock protector, and the leakage protection cannot be conditioned and at the cost of the human body electric shock.

SUMMERY OF THE UTILITY MODEL

An embodiment of the utility model provides a protection ground protection device for solve among the prior art ground protection reliability poor and the not good problem of electric shock protector effect.

On the one hand, the embodiment of the utility model provides a protection ground protection device, include:

the voltage detection unit is connected between a metal shell and a grounding electrode of the electrical equipment to detect the voltage between the metal shell and the grounding electrode, and generates a trigger signal when the detected voltage exceeds a set threshold value;

and the intermediate relay is electrically connected with the voltage detection unit and is provided with a normally closed contact, the normally closed contact is used for being connected in series in a circuit breaker closing circuit of the main circuit, and when the intermediate relay receives a trigger signal, the normally closed contact is opened to control the main circuit to be powered off.

In one possible implementation manner, the method further includes: an alarm; the intermediate relay is also provided with a normally open contact which is connected with the alarm in series, when the intermediate relay receives the trigger signal, the normally open contact is closed, and the alarm sends alarm information.

In one possible implementation, the alarm has a speaker, and the alarm information gives out a warning voice to the speaker.

In one possible embodiment, the alarm device has a light-emitting unit, for which the alarm information emits light.

In one possible implementation, the voltage detection unit has a display screen for displaying the detected voltage.

The utility model provides a protection ground protection device has following advantage:

1. the grounding protection reliability can be fundamentally improved without considering which reason causes the grounding protection failure, and the reason of the grounding protection failure is carefully checked after the grounding protection action.

2. Ground protection no longer is the preliminary examination, stresses the safety measure repeatedly, the utility model discloses ground protection's overall process protection is realized to state that can real time monitoring ground protection.

3. When the voltage to earth of the shell is detected to be larger than a threshold value in real time, tripping is carried out, so that electric shock of personnel can be effectively avoided; rather than detecting a fault in the ground protection at the expense of an electric shock to the person.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.

Fig. 1 is a schematic diagram illustrating a protective ground protection device according to an embodiment of the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative efforts all belong to the protection scope of the present invention.

Fig. 1 is a schematic diagram illustrating a protective ground protection device according to an embodiment of the present invention. An embodiment of the utility model provides a protection ground protection device, include:

the voltage detection unit is connected between a metal shell and an earth electrode of the electrical equipment to detect the voltage between the metal shell and the earth electrode, and when the detected voltage exceeds a set threshold value, the voltage detection unit generates a trigger signal;

For example, the voltage detection unit may employ a single-phase digital display voltmeter having a display screen for displaying the detected voltage. In the embodiment of the utility model, the input power of the voltage detection unit is 220V,50Hz commercial power, 5W power consumption, 1.0% precision, the measurement result is the true effective value of voltage, the unit is V, the display screen can adopt 4-bit LED, and the sampling frequency can be selected between 2-20 times/second. The output trigger signal can be selected from 12V, 24V and 36V.

The embodiment of the present invention provides a sampling frequency of the voltage detection unit is set to 20 times/second, so the sampling frequency of the voltage detection unit is required to be 0.05 second, i.e. 20 times per second, because the current affects the human body and is related to the size of the electric shock current, the length of the power-on time, the frequency of the ac power supply, and the path of the current. For 50Hz alternating current, the electric shock current reaches 50-100mA, and the death can be caused when the electrifying time exceeds 3 seconds. 0.05 second is 60 times less than 3 seconds. Moreover, the alternating current effective value of the set threshold value of the voltage detection unit can be selected in 12V, 24V and 36V, therefore the utility model discloses guarantee the safety of electric shock current and circular telegram time from two dimensions of trigger voltage and sampling period.

Normally, the main circuit is generally provided with a circuit breaker, and the circuit breaker is also provided with a tripping coil. If the main circuit is provided with a breaker, the normally closed contact of the intermediate relay can be connected in series in the closing circuit of the breaker. When the intermediate relay receives the trigger signal sent by the voltage detection unit, the normally closed contact is automatically disconnected, so that the main circuit is powered off, and the risk of electric shock of personnel is eliminated.

In one possible embodiment, the method further comprises: an alarm; the intermediate relay is also provided with a normally open contact which is connected with the alarm in series, when the intermediate relay receives the trigger signal, the normally open contact is closed, and the alarm sends alarm information.

Illustratively, the alarm has a speaker and/or a light-emitting unit, and when the speaker is employed, the alarm information gives an alarm voice to the speaker. And when the light-emitting unit is adopted, the alarm information is that the light-emitting unit emits light.

In the embodiment of the present invention, the capacity of the normally open contact and the normally closed contact is 250V/3A. The input power supply of the alarm is 220V,50Hz commercial power, when the mode that the luminous unit emits light is adopted to generate alarm information, the luminous unit can flash at the set frequency, when the mode that the loudspeaker emits warning voice is adopted to generate alarm information, voice can be recorded in advance and stored in the alarm, and the alarm volume can be adjusted between 1 decibel and 120 decibel.

Besides the above-mentioned advantage of ensuring personnel safety, the utility model discloses a protection device still has low-cost advantage. The electric shock protector in the traditional grounding protection mode detects zero-sequence current at milliampere level, and has higher requirement on the precision of an ammeter. And the utility model discloses the voltage that the single-phase digital display voltmeter of well adoption surveyed is the volt level, and is very low to the required precision of voltmeter, and the precision is low, and the cost is just low. In addition, if the alarm is not installed, the core performance of the alarm cannot be influenced, but the cost can be further reduced.

While the preferred embodiments of the present invention have been described, additional variations and modifications in those embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. It is therefore intended that the appended claims be interpreted as including the preferred embodiment and all such alterations and modifications as fall within the scope of the invention.

It will be apparent to those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims and their equivalents, the present invention is also intended to include such modifications and variations.

Claims

1. A protective earth protection device, comprising:

the intermediate relay is electrically connected with the voltage detection unit and provided with a normally closed contact, the normally closed contact is used for being connected in series in a circuit breaker closing circuit of a main circuit, and when the intermediate relay receives the trigger signal, the normally closed contact is opened to control the main circuit to be powered off.

2. A protective earth protection device according to claim 1, further comprising:

an alarm;

the intermediate relay is also provided with a normally open contact which is connected with the alarm in series, when the intermediate relay receives the trigger signal, the normally open contact is closed, and the alarm sends alarm information.

3. A protective earth protection device according to claim 2, wherein the alarm has a speaker, and the alarm information gives out an alarm voice to the speaker.

4. A protective earth protection device according to claim 2, wherein said alarm has a light emitting unit, and said alarm information is said light emitting unit.

5. The device of claim 1, wherein the voltage detection unit has a display screen for displaying the detected voltage.