JP3395401B2 - Instrument transformer equipment - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an instrument transformer connected to a busbar having a switchgear and detecting the voltage of the busbar. The present invention relates to a transformer device for an instrument that suppresses

[0002]

2. Description of the Related Art For example, in an instrument transformer connected to a gas-insulated switchgear disclosed in Japanese Utility Model Laid-Open No. 59-99609, a switching surge occurs when a disconnector is opened and closed.
This switching surge consists of a high frequency with a voltage that is about twice as high as the voltage at steady state, enters the primary side of the transformer for instruments via the busbar of this disconnector, and further the stray capacitance and electromagnetic force of the transformer for instruments. Transfer to the secondary side of the instrument transformer via coupling.
In the high frequency region of several MHz of switching surge, the voltage that shifts to the secondary side reaches about 20 times the steady partial pressure (about 350 V) of the switching surge voltage due to the resonance phenomenon of the instrument transformer. There were cases in which electrical damage to equipment such as protective relays connected to the secondary side line was caused. Conventionally, with respect to such switching surges, for example, a protective device such as a surge arrester or a capacitor is provided on the secondary side of the instrument transformer to suppress the transition voltage to the secondary side.
It was configured to prevent electrical breakdown of equipment such as protective relays connected to the secondary line.

[0003]

However, the phenomenon of secondary transfer of high-frequency switching surge is complicated, and even if the above-mentioned protective device is used, the effect differs depending on the insertion location, and the secondary device is connected to the secondary side. Since the level of the abnormal voltage due to the surge varies depending on the installation location of the device, there is a problem that the surge measurement test must be repeated many times in the field. Also, with the above protection device alone,
There is a problem in that the level of the abnormal voltage cannot be suppressed and the abnormal voltage may reach 4 KV.

The present invention has been made to solve the above problems, and is more effective and economical in order to suppress abnormal voltage generation on the secondary side of a transformer for instruments due to switching surge. The purpose is to obtain a typical instrument transformer device.

[0005]

SUMMARY OF THE INVENTION An instrument transformer device according to the present invention is a resistor connected to a conductor branched from a bus bar having a switchgear, and an instrument connected via the resistor. Equipped with a transformer, the resistor is the primary side of the instrument transformer
Is provided adjacent to . Further, the resistor is provided in a case accommodating the main body of the instrument transformer. Further, a resistance conductor combination unit in which the periphery of the central conductor is covered with a resistance body instead of the above resistance body is provided.

[0006]

In the instrument transformer device according to the present invention, the resistor provided on the primary side of the instrument transformer restricts the switching surge generated in the switch device from entering the instrument transformer main body. Suppresses abnormal voltage that moves to the secondary side of the instrument transformer. In addition, the resistor that is built into the case that houses the main body of the instrument transformer and is installed on the primary side of the instrument transformer prevents the switching surge generated by the switchgear from entering the instrument transformer body. To limit the abnormal voltage that shifts to the secondary side of the instrument transformer. In addition, the resistance conductor combination unit, which is provided on the primary side of the instrument transformer and covers the center conductor with a resistor, restricts the switching surge generated in the switchgear from entering the instrument transformer main body. , Suppress the abnormal voltage that shifts to the secondary side of the instrument transformer.

[0007]

【Example】

Example 1. 1 is a structural view showing a transformer device for meters according to a first embodiment of the present invention (in the drawings, the hatched portion shows a cross section, and other drawings are the same). In FIG. 1, 1 is a container of a gas-insulated switchgear. Reference numeral 2 is a container for a connecting busbar, 3 is a transformer for a gas insulation instrument, 4 is a container for a transformer for a gas insulation instrument, 5 is a main body provided in the container 3 and including a winding portion of the transformer for a gas insulation instrument. Part, 6 is an insulating spacer for separating the container 2 and the container 4, 6a is a conductor attached to the insulating spacer 6, 7a
Is a conductor connecting the primary side of the main body 5 and the conductor 6a, 8 is a conductor provided in the container 1 and branched from the busbar of the switchgear, 9
Is a connecting conductor for connecting the conductor 8 and the gas insulation voltage transformer, 10 is a resistor connecting the conductor 6a of the insulating spacer 6 and the connecting conductor 9 and having a predetermined electric resistance. Is the solid resistance 11 and this solid resistance 11
And an end fitting 13 and 14 which is provided at both ends of the insulating pipe 12 and covers the solid resistor 11 and the connecting conductor 9 and the conductor 6a, respectively.
Have and.

FIG. 2 is a circuit diagram showing an equivalent circuit of the transformer device for a meter of the first embodiment. In FIG.
Is a transformer included in the instrument transformer main body 5, 16 is an electric resistance of the resistor 10, 17 is a high-voltage side circuit connected to the conductor 8, and 18 is a low-voltage side circuit connected to the secondary side of the transformer 15.

Next, the operation will be described. The high-frequency surge due to the switching surge generated in the gas-insulated switchgear enters the main body 5 of the instrument transformer through the bus 8, the conductor 8, the connecting conductor 9, the resistor 10, the conductor 6a, and the conductor 7. As shown in FIG. 2, which is an equivalent circuit, the resistor 16 of the resistor 10 is inserted between the high voltage side circuit 17 and the instrument transformer 15.
The high frequency surge from the high voltage side circuit 17 is suppressed by the resistor 16. Therefore, the resonance phenomenon in the transformer 15 is also suppressed, and the voltage to the low voltage side circuit 18 of the transformer 15 is reduced.
The next transition can also be prevented. If the resistor 16 is selected from 10 Ω to several hundreds Ω, the high-frequency surge voltage will be reduced to about half, compared with the case where the resistor 16 of the resistor 10 is directly passed through the path and entered into the transformer 15 as it is. Can be suppressed. Therefore, the conventional protection device connected to the low voltage side circuit 18 becomes unnecessary, and by providing the resistor 16 on the primary side of the transformer 15, high frequency surge can be suppressed. The larger the resistance value of the resistor 16 of the resistor 10, the greater the effect of suppressing the surge voltage, but if the resistance value becomes too large, the error in the steady state of the instrument transformer 3 becomes large, and therefore the resistance value becomes large. It is desirable that the value is 1Ω or more and 10 MΩ or less. The steady-state current on the primary side of the instrument transformer 3 is 1A.
Since it is as small as follows, the heat loss due to the resistor 10 does not become so large. In FIG. 1, the resistor 1
Although the solid resistance 11 is used for the example of 0, the resistance is ferrite, zinc oxide type resistance, winding type resistance,
Alternatively, the same effect can be obtained with a thin film resistor.

Embodiment 2. Second Embodiment FIG. 3 is a structural diagram of an instrument transformer device showing a second embodiment of the present invention.
Is a conductor that connects the connecting conductor 9 and the conductor 6a, and 20 is a conductor 6a of the insulating spacer 6 and 1 of the main body 5 of the instrument transformer 3.
The resistor 20 is a resistor that has a predetermined electric resistance and is connected to the next side. As in the case of the first embodiment, the resistor 20 includes a solid resistor 21 and an insulating pipe 22 that covers the solid resistor 21. It has end fittings 23 and 24 which are provided at both ends of the insulating pipe 22 and which connect the solid resistor 21 to the conductor 6a and the primary side of the main body 5, respectively. Other reference numerals are the same as those in FIG. 1 showing the first embodiment. In the instrument transformer device of the second embodiment, the resistor 20 is provided in the container 4 of the main body 5 of the instrument transformer in place of the resistor 10 of the first embodiment. The same effect as can be obtained. Further, since the resistor 20 is provided in the same container 4 as the main body 5 of the instrument transformer 3 with the insulating spacer 6 interposed therebetween, the resistor 20 is separated from the gas-insulated switchgear side and the container 4 of the instrument transformer 3 is separated. This has the effect that the resistor 20 can be maintained simply by removing.

Embodiment 3. FIG. 4 is a structural diagram of an instrument transformer device showing a third embodiment, in which a capacitor type instrument transformer is used instead of the instrument transformer 3 of FIG. 1 showing the first embodiment. In FIG. 4, reference numeral 25 is a capacitor type instrument transformer, and 26 is this capacitor type instrument transformer 2
5, a container accommodating the porcelain insulator 27 and the conductor 7, 28 is a capacitor, and other reference numerals are the same as those in FIG. 1 showing the first embodiment. In the third embodiment, the resistor 10 is provided on the primary side of the capacitor type instrument transformer 25.
The same effect as that of the first embodiment is obtained.

Embodiment 4. FIG. 5 is a structural diagram of an instrument transformer device showing a fourth embodiment, in which an optical instrument transformer is used instead of the instrument transformer 3 of FIG. 1 showing the first embodiment. In FIG. 5, 29 is a transformer for an optical instrument, 30 is a container in which the main body of the transformer for an optical instrument is housed, 31 is a conductor provided inside the transformer, 32 is an intermediate electrode, 33
Is a secondary side capacitor, 34 is an optical sensor, 35 is a conductor connecting the circuits of the capacitor 33 and the optical sensor, and other reference numerals are the same as those in FIG. 1 showing the first embodiment. In the fourth embodiment, the resistor 10 is provided on the primary side of the optical instrument transformer 29, and the resistor 10 suppresses surge inflow to the primary side of the optical instrument transformer 29. An abnormal voltage is prevented from being generated in the capacitor 33 and the optical sensor 34, which are the secondary circuit, and the same effect as that of the first embodiment is achieved.

Embodiment 5. FIG. 6 is a structural diagram of a resistance conductor combination unit showing a fifth embodiment, and this resistance conductor combination unit is used, for example, in place of the resistor 10 of FIG. 1 of the first embodiment. In FIG. 6, 36 is a resistance conductor combination unit, 37 is a conductor, and this conductor 37 is provided with conductor ends 37a and 37c formed on a plate at both ends of the center conductor 37b, and the periphery of the center conductor 37b. Is covered with a cylindrical resistor 38. The resistance conductor combination unit 36 works as an electric resistance only against the high frequency surge due to the switching surge due to the high frequency skin effect. Therefore, if it is used in place of the resistor 10 or 20, the same effect as that of the other embodiments can be obtained. be able to. Further, since the resistance conductor combination unit 36 functions as a conductor in the normal frequency region, the resistance value in the high frequency region due to the high frequency surge is increased and the surge suppression is performed without causing an error in the steady state of the instrument transformer. There is an effect that the effect can be set large. .

[0014]

Since the instrument transformer device of the present invention is constructed as described above, it has the following effects. Since the resistor suppresses the switching surge that flows into the primary side of the instrument transformer, the surge has an effect of preventing an abnormal voltage generated on the secondary side of the instrument transformer. Furthermore, there is an effect that an instrument transformer device having an effective and economical switching surge suppression effect can be obtained with a simple configuration using only resistors. Further, since the resistor is provided in the case accommodating the main body of the instrument transformer, there is an effect that the resistor can be maintained only by removing the case of the instrument transformer.
In addition, instead of the above resistor, a resistance conductor combination unit in which the center conductor is covered with a resistor is provided, so that the high frequency skin effect allows it to act as an electrical resistance against the high frequency surge due to the switching surge. There is an effect that the resistance value in the high frequency region can be increased and the surge suppression effect can be set large.

[Brief description of drawings]

FIG. 1 is a structural diagram showing an instrument transformer device according to a first embodiment of the present invention.

FIG. 2 is an equivalent circuit diagram showing a transformer device for a meter according to the first embodiment of the present invention.

FIG. 3 is a structural diagram showing an instrument transformer device according to a second embodiment of the present invention.

FIG. 4 is a structural diagram showing an instrument transformer device according to a third embodiment of the present invention.

FIG. 5 is a structural diagram showing an instrument transformer device according to a fourth embodiment of the present invention.

FIG. 6 is a structural diagram of a resistance conductor combination unit according to a fifth embodiment of the present invention.

[Explanation of symbols]

3 Instrument transformer 5 Instrument transformer main body 10 Resistor 20 Resistor 25 Capacitor type instrument transformer 29 Optical instrument transformer 36 Resistor conductor combination unit 37b Center conductor 38 Resistor

Claims (4)

(57) [Claims] 1. A conductor branched from a bus bar having a switchgear.
Connected thereto resistor to comprise a voltage transformer which is connected via the resistor, resistor, et al provided adjacent to the primary side of the voltage transformer
A transformer device for instruments characterized by being 2. A closing device is a gas insulated switchgear, instrument transformer according to claim 1 Symbol placement, wherein the instrument transformer is a transformer for a gas insulated instrument. The 3. A resistor, characterized in that provided in the casing that contains the body of the transformer for a gas insulated instrument according to claim 1
Or the transformer for measuring instrument according to 2 . Wherein instead of the resistor, instrument unit according to any one of claims 1 to 3, characterized in that it comprises a resistance conductor combination unit covering the periphery of the central conductor in the resistor.