KR102018903B1 - Test Plug with Preventing Apparatus Overvoltage - Google Patents

Abstract

The present invention relates to a test plug having an overvoltage prevention device, which is inserted into a test terminal installed in a switchgear to inspect a device using a three-phase four-wire current transformer and is connected to a tester for inspecting the device. The test plug having an overvoltage prevention device of the present invention comprises: a test terminal insertion unit including each first conductor connected to a power supply side conductor on an upper part thereof, each second conductor connected to a load side conductor on a lower part of the first conductor, and an insulator interposed between the first and second conductors to electrically separate the power supply side conductor and the load side conductor from each other; a fixing unit body having one side end of the first and second conductors of the test terminal insertion unit fixed to one side thereof; a terminal for connection of each tester, penetrating the fixing unit body and protruding from the other side of the fixing unit body to be connected to a tester for inspecting a device; and an overvoltage sensing device including six first connection lines separately connected to a three-phase line of a power supply side and a load side, six second connection lines separately connected to a ground line of the power supply side and the load side among four lines, and overvoltage sensing units separately interposed between the first and second connection lines, short-circuiting the first and second connection lines at normal times and allowing the same to be conducted when an overvoltage is generated to prevent the opening of a secondary winding of a current transformer.

Description

Test Plug with Preventing Apparatus Overvoltage

The present invention is a test plug for checking the instrument, protective relay, etc. of the live switchgear using a current transformer, by preventing the opening of the secondary winding of the current transformer in the test plug itself during the inspection to prevent safety accidents due to the opening of the secondary winding The present invention relates to a test plug equipped with an overvoltage protection device to protect human life and property.

In switchboards such as instruments and protective relays of live switchboards using current transformers, test terminals are provided for connection with a tester (e.g., clamp ammeter for measuring current by CT clamp) at the time of equipment inspection.

This test terminal includes a power supply conductor electrically connected to the power supply device and a load supply conductor electrically connected to a load device such as an instrument, and these devices are normally kept in an electrically connected state.

On the other hand, during the test, the plug portion of the test plug is inserted into the test terminal so that the electrical connection between the power supply side conductor and the load side conductor is separated, so that the load side conductor is not bound by the power supply side device and the terminal for connection of the test plug. The test is carried out by connecting to a tester or the like according to the wiring through a connecting plug. After the test, the power supply side conductor and the load side conductor are electrically connected again by removing the test plug from the test terminal.

In general, when the secondary winding of the current transformer in which the current flows in the primary winding is opened, overvoltage is induced in the secondary winding, which may cause damage to the terminal block, fire or human contact.

In order to prevent this problem, the secondary winding of the current transformer during the maintenance and repair work should always be short-circuited, and this should be done using the current transformer test terminal (CTT) and the test plug installed in the switchgear.

Normally, the CTT connects the measuring or protective relay side conductor and the current transformer secondary winding side conductor by using the spring pressure, and physically separates the circuit by inserting the test plug.

The current test plug uses a short circuit bar made of metal to prevent the secondary winding of the current transformer.However, if a fault occurs between the current transformer side of the power supply unit and the meter and protective relay side of the load side device, the short circuit bar is incorrectly installed. There is a problem that can lead to the opening of the lane.

On the other hand, in order to prevent the safety accidents caused by the opening of the secondary winding to prevent damage to the equipment and damage to life, there are cases in which the switchgear panel is equipped with an instrument current transformer open state monitoring and protection device.

An example of a switchgear equipped with an instrument current transformer open state monitoring and protection device has been disclosed Korean Patent No. 10-1451389 (Invention: Switchgear equipped with an instrument current transformer open state monitoring and protection device).

The disclosed current transformer current condition monitoring and protection device outputs a secondary protection circuit generation signal to the outside when the measured voltage value is higher than the reference voltage value by the control unit for the protection circuit delay time. After outputting the protective circuit generation signal to the outside, when the measured voltage value is higher than the reference voltage value and lasts for the input short-circuit delay time, the second terminal open signal should be output to the outside. There is this. In addition, when receiving the secondary protection circuit generation signal from the control unit, the secondary protection circuit generation unit to form a circuit connected to the secondary terminal of the current transformer for the instrument as a closed circuit electrically connected only to the relay, so that the secondary The structure of the protection circuit generator also has a complicated problem.

In addition, in the case of a switchgear that is not equipped with the current transformer open state monitoring and protection device for the instrument, when a test plug is used to check the gauge and the protective relay of the live switchgear, a short circuit bar may be incorrectly installed, which may lead to the opening of the secondary winding of the current transformer. There will be a problem.

The present invention has been made to solve the above problems, an object of the present invention, to prevent the opening of the current transformer secondary winding in the test plug itself for the inspection of the instrument, protective relay, etc. of the live switchgear using a current transformer. It is to provide a test plug equipped with an overvoltage protection device to protect human life and property by preventing safety accidents due to the opening of the secondary winding.

Test plug equipped with an overvoltage protection device of the present invention for achieving the above object is inserted into a test terminal installed in the switchgear for the inspection of the instrument using a current transformer, such as a three-phase four-wire live switchgear instrument, a protective relay A test plug which separates electrical connection between the power supply conductor and the load conductor and is connected to the tester for checking the equipment, the test plug being formed long in the longitudinal direction so as to be inserted into the test terminal, and each first conductor connected to the power supply conductor at the top. (11a, 11b, 11c, 11d), and second conductors (12a, 12b, 12c, 12d) connected to the load side conductors under the first conductors (11a, 11b, 11c, 11d), and the second Interposed between the first conductors 11a, 11b, 11c, and 11d and the second conductors 12a, 12b, 12c, and 12d, and the first conductors 11a, 11b, 11c, and 11d and the second conductors 12a, 12b, 12c, and 12d are electrically insulated so that the power supply conductor and the load A test terminal insertion portion 10 formed of an insulator 13 which electrically separates the sieves from each other; One end of the first conductors 11a, 11b, 11c, and 11d of the test terminal insertion part 10 and the second conductors 12a, 12b, 12c, and 12d of the test terminal insertion part 10 on one side thereof. One end of the fixing part body 20 is fixed; One end of each of the first conductors 11a, 11b, 11c, and 11d and one end of each of the second conductors 12a, 12b, 12c, and 12d are coupled to each other and penetrate the fixing body 20. And each tester connection terminal 30 protruding to the other side of the fixing unit main body 20 so as to be connected to a tester for checking the device. The fixing part main body 20 is provided with one end portion of the first conductors 11a, 11b, 11c, and 11d and the second conductors 12a, 12b, 12c, and 12d of the test terminal inserting portion 10. Six first connection lines 41 coupled to one end or each of the tester connection terminals 30 and respectively connected to a power supply side and a load side three-phase line, and six first connection lines respectively connected to the power supply side and the load side ground wire. It is interposed between the second connection line 42 and the first connection line 41 and the second connection line 42, respectively, and short-circuits the first connection line 41 and the second connection line 42 with each other, and when an overvoltage occurs, It is characterized in that it comprises a; and an overvoltage sensing device (40) consisting of each overvoltage sensing unit (43) for energizing to prevent the opening of the secondary winding of the current transformer.

In addition, one end of the first conductors 11a, 11b, 11c, and 11d of the test terminal insertion unit 10 and the second conductors 12a, 12b, 12c of the test terminal insertion unit 10, 12d) is fixed to the fixed portion main body cover 50 is coupled to one side of the fixed portion main body 20 so as to cover the one end portion is fixed; characterized in that it is further provided.

In addition, the fixing part body 20 or the fixing part body cover 50 is provided with an accommodating part 51 for accommodating the overvoltage detecting device 40 so that the overvoltage detecting device 40 is fixed to the fixing part. It is characterized in that it is interposed between the main body 20 and the fixed part main cover 50.

The test plug provided with the overvoltage protection device of the present invention having the above-described configuration, even if the short-circuit bar which is implemented when the operator installs the test plug as in the prior art, opens the secondary winding of the current transformer, the overvoltage detecting unit operates. By preventing the secondary winding side from being opened, damage to the equipment and damage to life can be prevented. In addition, the test plug itself has a simple structure and an overvoltage detector, which does not include a complicated control unit or a complicated secondary protection circuit generation unit, compared to a conventional instrument current transformer open state monitoring and protection device. It is cheaper. In addition, it is possible to replace and reuse only the overvoltage detection unit used in the event of overvoltage, and to carry only a test plug, there is an advantage that it can be safely used in a current transformer without an instrument current monitoring and protection device installed.

1 and 2 are perspective views showing a test plug provided with an overvoltage preventing device according to the present invention.
3 is an exploded perspective view showing a test plug provided with an overvoltage preventing device according to the present invention.
4 is a view showing a schematic structure of a test plug provided with an overvoltage protection device according to the present invention.
5 is a cross-sectional view illustrating a schematic structure of an overvoltage detection device of a test plug with an overvoltage prevention device according to the present invention.

Hereinafter, a test plug provided with an overvoltage preventing device of the present invention will be described in detail with reference to the accompanying drawings.

1 and 2 is a perspective view showing a test plug with an overvoltage protection device according to the present invention, Figure 3 is an exploded perspective view showing a test plug with an overvoltage protection device according to the present invention, Figure 4 is FIG. 5 is a view illustrating a schematic structure of a test plug having an overvoltage preventing device according to the present invention, and FIG. 5 is a cross-sectional view illustrating a schematic structure of an overvoltage detecting device of a test plug having an overvoltage preventing device according to the present invention.

The test plug with an overvoltage protection device according to the present invention is inserted into a test terminal installed in the switchgear for inspection of the instrument of the three-phase four-wire live switchgear and a device using a current transformer, such as a protective relay, and the power-side conductor and the load-side conductor. It disconnects the electrical connection with the tester and serves to connect the tester to check the equipment.

Test plug provided with an overvoltage protection device according to the present invention, the test terminal insertion portion 10; A fixing unit body 20; A terminal 30 for connecting a tester; And an overvoltage detector 43.

The test terminal insertion unit 10 is inserted into the test terminal and is formed long in the longitudinal direction to be inserted into the test terminal. The test terminal is provided with a power supply conductor connected to the power supply side and a load side conductor connected to the load side on the up, down, left and right sides, respectively. In the present invention, the power supply side conductor and the load side conductor are respectively provided on the test terminal, the power supply side conductor is provided on the upper side, and the load side conductor is provided on the lower side.

In the case of a three-phase four-wire system, four power supply conductors and four load side conductors are provided. One power-side conductor is connected to the ground wire, and the other three power-side conductors are connected to each of the three phases. The same applies to the load-side conductor.

As illustrated in FIGS. 1 to 3, the test terminal inserting portion 10 includes four first conductors 11a, 11b, 11c, and 11d, four second conductors 12a, 12b, 12c, and 12d. And an insulator 13.

Each of the first conductors 11a, 11b, 11c, and 11d is connected to a power supply side conductor at an upper portion thereof. Here, the first conductor 11d is defined as being connected to the power supply ground ground.

Each of the second conductors 12a, 12b, 12c, and 12d is provided below the respective first conductors 11a, 11b, 11c, and 11d, and is connected to the load side conductor. The second conductor 12d is defined as being connected to the load side ground line.

The insulator 13 is interposed in a space between the first conductors 11a, 11b, 11c, and 11d and the second conductors 12a, 12b, 12c, and 12d, and the first conductors 11a, 11b, 11c, 11d and the second conductors 12a, 12b, 12c, and 12d are fixed, and the first conductors 11a, 11b, 11c, and 11d and the second conductors 12a, 12b, 12c, and 12d are fixed. It electrically insulates and electrically isolates the power and load conductors from each other. The insulator 13 may be four according to the shape of the test terminal, and may be one. In the present invention, four test terminals are made, and the insulator 13 is also made of four.

The test terminal insertion portion 10 is preferably made upside down symmetric so that it can be inserted upside down in the test terminal.

The fixing part main body 20 fixes the test terminal insertion part 10, and at one side, one side of each of the first conductors 11a, 11b, 11c, and 11d of the test terminal insertion part 10. An end and one end of each of the second conductors 12a, 12b, 12c, and 12d of the test terminal insert 10 are fixed (see FIG. 3).

As shown in FIG. 3, the tester connection terminal 30 has one end of each of the first conductors 11a, 11b, 11c, and 11d and the second conductors 12a, 12b, 12c, and 12d, respectively. One end of each is coupled and penetrates through the fixing unit body 20 and protrudes to the other side of the fixing unit body 20 so as to be connected to a tester for checking the device. The tester connection terminal 30 is provided with a fastener 31 for fixing a shorting bar and fixing a connecting portion connected to the tester (see FIGS. 1 to 3).

The overvoltage detecting device 40 is provided in the fixing unit main body 20 and has one end portion of the first conductors 11a, 11b, 11c, and 11d and the second conductor of the test terminal inserting portion 10 ( One end of 12a, 12b, 12c, and 12d, or each of the terminals 30 for connecting the tester.

In this case, the overvoltage detecting device 40 includes a first connecting line 41, a second connecting line 42, and an overvoltage detecting unit 43, as shown in FIGS. 4 and 5.

The first connection line 41 is connected to each of the three phases, a total of six.

The second connection line 42 is connected to the ground line among the four lines, respectively, and consists of a total of six.

The overvoltage detecting unit 43 is interposed between the first connecting line 41 and the second connecting line 42, respectively, to short-circuit the first connecting line 41 and the second connecting line 42, and to overvoltage each other. When it occurs, it is energized with each other to prevent the opening of the secondary winding of the current transformer, and is interposed between the three first connecting line 41 and three second connecting line 42, it consists of a total of six.

The power-side three-phase wire and ground wire and the load-side three-phase wire and ground wire are connected to the first conductors 11a, 11b, 11c, and 11d and the second conductors 12a, 12b, 12c, and 12d by insertion of the test terminal inserting portion 10. The one end of the first conductor (11a, 11b, 11c, 11d) and the second conductor (12a, 12b, 12c, 12d) is connected to the terminal 30 for the tester connection, The power-side three-phase wire and ground wire and the load-side three-phase wire and ground wire are electrically connected to each tester connection terminal 30. When the first connection line 41 and the second connection line 42 are connected to each of the tester connection terminals 30, it can be seen that the three-phase line and ground line and the load-side three-phase line and ground line.

As shown in the figure, the first connection line 41 and the second connection line 42 are shown to be connected to the respective tester connection terminals 30, indicating that they are connected to the power supply three-phase line and the ground line and the load-side three-phase line and the ground line. it means.

One overvoltage sensing device installed on the power supply side includes one power supply three-phase wire (i.e., a tester connection terminal 30 shown by reference numerals 1, 3, and 5 in FIG. 4) and a power supply grounding wire (i.e., FIG. 4). Means the tester connection terminal 30 shown in Fig. 7), and the other overvoltage detecting device installed on the power supply side connects the other power supply three-phase line and the power supply ground ground to each other. The other one of the overvoltage sensing devices installed in the circuit connects the remaining three-phase power line and the ground side of the power supply.

In addition, one overvoltage sensing device installed on the load side includes one load-side three-phase wire (that is, the tester connection terminal 30 shown by reference numerals 2, 4, and 6 in FIG. 4) and the load-side ground wire (that is, 4 means the tester connection terminal 30 shown in FIG. 4), and another overvoltage sensing device installed at the load side connects the other load-side three-phase line and the load-side ground line to each other. The other overvoltage sensing device installed on the load side connects the remaining three phase line of the load side and the ground side of the load side.

As described above, according to the present invention, since the overvoltage detecting device 40 is provided in the fixing unit main body 20, it is not only convenient to use, but also a secondary current transformer is installed by incorrectly installing short-circuit bars which the operator implements when installing the test plug. Even if the opening occurs, the overvoltage detection unit is operated to prevent the secondary winding side from being opened, thereby preventing damage to the equipment and human injury.

If the power supply side and the load side are firmly identified, short circuit bars may be installed on the load side and the test may be performed. Only three overvoltage sensors may be installed on the load side. However, since the test terminal inserting portion 10 is vertically symmetrical, since the test terminal inserting portion 10 can be inserted upside down and inserted into the test terminal, the six overvoltage detecting devices 40 are provided.

In this way, if the overvoltage detecting device 40 is provided at the power supply side and the load side with six, the test plug can be prevented even if opening of the current transformer secondary winding occurs when the test plug is inserted upside down.

The present invention, one end of the first conductor (11a, 11b, 11c, 11d) of the test terminal insertion section 10 and the second conductor (12a, 12b) of the test terminal insertion section 10, 12c and 12d, the fixing unit body cover 50 coupled to one side of the fixing unit main body 20 is further provided to cover a portion where the one end is fixed (see FIGS. 1 to 3), and the first conductor It is preferable not to expose a portion to which one end of (11a, 11b, 11c, 11d) and one end of the second conductor 12a, 12b, 12c, 12d of the test terminal inserting portion 10 are fixed. . The fixing unit body cover 50 is provided to be detachable from the fixing unit body 20. In FIG. 3, the fixing unit body cover 50 is coupled to the fixing unit body 20 by screwing, but the fixing unit body cover 50 has protrusions or grooves, and the fixing unit The fixing part body cover 50 and the fixing part main body 20 may be coupled to each other by a groove or a protrusion provided in the main body 20.

When the overvoltage detecting device 40 is installed, when the first connection line 41 and the second connection line 42 are connected, the overvoltage detecting device 40 may be connected to the tester connection terminal 30, but the fixing unit body 20 may be used. Since the shorting bar is installed in the tester connection terminal 30 protruding to the other side, the other side of the fixing part main body 20 may be complicated.

In order to prevent this, the overvoltage detecting device 40 is provided in the fixing part main body 20 or the fixing part main cover 50 so that the accommodating part 51 for accommodating the overvoltage detecting device 40 is provided. It is interposed between the fixing unit body 20 and the fixing unit body cover 50. In the figure, it is shown that the receiving portion 51 is provided in the fixing portion main cover 50 (see Fig. 3).

Each of the overvoltage detectors 43 includes a pair of spacer plates 43a, a low-temperature melting conductor 43b, and a housing 43c, as shown in FIG.

The spacer plate 43a is connected to the first connection line 41 and the second connection line 42, respectively, and is spaced apart from each other to short-circuit the first connection line 41 and the second connection line 42. , It consists of a pair.

The low-temperature melting conductor 43b is installed outside the separation plate 43a and is melted by overheating due to overvoltage generation, thereby connecting the separation plate 43a to each other so as to connect the first connection line 41 and the first connection line 41 to the first connection line 41. The second connection line 42 is connected to each other. The low-temperature molten conductor 43b is melted when the temperature rises when an overvoltage occurs, and the spacer 43a is connected to each other to be electrically conductive. The low temperature melting conductor 43b uses a metal body that can be melted at a low temperature.

The enclosure 43c serves to accommodate the spacer plate 43a and the low temperature molten conductor 43b.

As described above, the present invention is not only provided with a complicated control unit or a complicated secondary protection circuit generation unit, but also has a simple overvoltage sensing device in the test plug itself, which is convenient to use, as compared with the conventional instrument current transformer open state monitoring and protection device. Rather, the price is low.

In addition, it is possible to replace and reuse only the overvoltage sensing device used in the event of overvoltage, and to carry the test plug alone has the advantage that it can be safely used in the current transformer without the current transformer monitoring condition and protection device installed.

The technical idea should not be construed as being limited to the above-described embodiment of the present invention. Various modifications may be made at the level of those skilled in the art without departing from the spirit of the invention as claimed in the claims. Therefore, such improvements and modifications fall within the protection scope of the present invention as long as it will be apparent to those skilled in the art.

10: test terminal insert
11a, 11b, 11c, 11d: first conductor
12a, 12b, 12c, 12d: second conductor
13: insulator
20: fixed part body
30: Terminal for connecting tester
40: overvoltage detection device
41: first connection line
42: second connecting line
43: overvoltage detection unit
43a: separation plate
43b: Low Temperature Melt Conductor
43c: enclosure
50: fixing unit body cover
51: receptacle

Claims (3)

It is inserted into the test terminal installed in the switchgear for the inspection of the equipment using the current transformer such as the instrument and protection relay of the 3-phase 4-wire live switchgear, and it disconnects the electrical connection between the power supply conductor and the load conductor and connects to the tester for checking the equipment. To ensure that the test plug,
Long in the longitudinal direction to be inserted into the test terminal,
Each of the first conductors 11a, 11b, 11c, and 11d connected to the power supply-side conductor at an upper portion thereof, and each of the second conductors connected to the load-side conductor below the first conductors 11a, 11b, 11c, and 11d. 12a, 12b, 12c, and 12d, the first conductors 11a, 11b, 11c, and 11d and the second conductors 12a, 12b, 12c, and 12d are interposed between the first conductors 11a, 11b, A test terminal insertion portion (10) comprising an insulator (13) electrically insulating the second conductors (12a, 12b, 12c, 12d) from the power supply side conductors and the load side conductors;
One end of the first conductors 11a, 11b, 11c, and 11d of the test terminal insertion part 10 and the second conductors 12a, 12b, 12c, and 12d of the test terminal insertion part 10 on one side thereof. One end of the fixing part body 20 is fixed;
One end of each of the first conductors 11a, 11b, 11c, and 11d and one end of each of the second conductors 12a, 12b, 12c, and 12d are coupled to each other and penetrate the fixing body 20. And each tester connection terminal 30 protruding to the other side of the fixed part main body 20 so as to be connected to a tester for checking the device;
The fixing part main body 20 is provided with one end portion of the first conductors 11a, 11b, 11c, and 11d and the second conductors 12a, 12b, 12c, and 12d of the test terminal inserting portion 10. Six first connection lines 41 coupled to one end or each of the tester connection terminals 30 and respectively connected to a power supply side and a load side three-phase line, and six first connection lines respectively connected to the power supply side and the load side ground wire. It is interposed between the second connection line 42 and the first connection line 41 and the second connection line 42, respectively, and short-circuits the first connection line 41 and the second connection line 42 with each other, and when an overvoltage occurs, And an overvoltage detection device (40) comprising respective overvoltage detection parts (43) for energizing the current to prevent opening of the secondary winding of the current transformer. The method of claim 1,
One end of the first conductors 11a, 11b, 11c, and 11d of the test terminal insertion part 10 and the second conductors 12a, 12b, 12c, and 12d of the test terminal insertion part 10 on one side thereof. The test plug with an overvoltage prevention device, characterized in that it further comprises; a fixing unit body cover (50) coupled to one side of the fixing unit body (20) to cover a portion where one end of the fixing unit is fixed. The method of claim 2,
The fixing part main body 20 or the fixing part main cover 50 is provided with an accommodating part 51 for accommodating the overvoltage detecting device 40 so that the overvoltage detecting device 40 is connected to the fixing part main body. 20) and the test plug having an overvoltage preventing device, characterized in that interposed between the fixing unit body cover (50).

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