JPH11153628A - Received voltage detecting device for gas insulated electric equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the received voltage detecting device capable of easily knowing the level of the voltage that the gas insulated electric equipment is receiving on the spot of the equipment. SOLUTION: An electrode 3 for detection is arranged opposite the main circuit conductor 2 in the metal container 1 of the gas insulated electric equipment. A current detecting coil 5 which has one end grounded is arranged outside the metallic container 1 and the other end of the current detecting coil 5 is connected to the electrode 3 for detection through the center conductor of an insulation bushing 4. An ammeter 9 is provided which detects the current flowing to the current detecting coil 5 through a current transformer constituted by winding a secondary coil around an iron core 901 having a magnetic path cross- linked with the current detecting coil 5 and this ammeter 9 measures a leak current flowing through the electrostatic capacity between the main circuit conductor 2 and electrode 3 for detection. The display of the ammeter 9 is matched with the display of a received voltage by adjusting the resistance value of a variable resistor 8 connected in parallel to the current detecting coil 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a circuit breaker, a disconnector,
A gas insulated switchgear in which components of a switching circuit such as a bus conductor are housed in a metal container filled with insulating gas, and a gas insulated disconnector in which a disconnector is housed in a metal container filled with insulating gas. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a receiving voltage detecting device for a gas-insulated electric device for detecting a receiving voltage of a gas-insulated electric device such as a heater.

[0002]

2. Description of the Related Art A receiving voltage detecting device provided in a gas-insulated electrical device such as a gas-insulated switchgear or a gas-insulated disconnector uses a measuring transformer (PT or VT) to detect a main circuit conductor in a container. Either the voltage is detected, or the voltage of the main circuit conductor is detected through a voltage dividing circuit using capacitance.

A conventional receiving voltage detecting device is provided for the purpose of obtaining a voltage for operating a protection relay,
Since it was provided for the purpose of operating the display instrument provided on the monitoring panel, it was not possible to easily know the receiving voltage at the installation site of the gas-insulated electrical equipment.

Accordingly, the present applicant has previously described a gas-insulated electric device in which components of an electric device including a main circuit conductor to which a received voltage is applied are housed in a metal container filled with an insulating gas. An electrode for voltage detection arranged opposite to the main circuit conductor in the container and a center conductor of an insulating bushing arranged outside the metal container and having one end grounded and the other end airtightly penetrating the wall of the metal container. A current detecting coil connected to the charging electrode, and a current for detecting a small current flowing through the current detecting coil through a current transformer having a configuration in which a secondary coil is wound around an iron core having a magnetic path interlinked with the current detecting coil. Power supply applied to the main circuit conductor by detecting the leakage current flowing to the ground circuit through the capacitance between the main circuit conductor and the voltage detection electrode and the current detection coil with the ammeter. Voltage It was proposed to detect.

[0005]

As in the above-mentioned proposed invention, a current detection coil is inserted into a path of a leakage current flowing to a ground circuit through a capacitance between a main circuit conductor and a detection electrode. When a leakage current is detected by an ammeter through a current transformer in which a secondary coil is wound around an iron core having a magnetic path interlinking with the current detection coil, a minute leakage current is amplified and detected with high sensitivity. The received voltage of the gas-insulated electric device can be obtained from the detected value.

However, in the above method, the magnitude of the received voltage cannot be immediately known from the display of the ammeter, and in order to determine the magnitude of the received voltage, an operation for converting the display of the ammeter into a voltage value is performed. Due to the necessity, there is a problem that an operator who performs maintenance and inspection at the installation site of the gas insulated electric device cannot easily know the magnitude of the receiving voltage.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a receiving voltage detecting device for gas insulated electric equipment which enables an operator to easily know the magnitude of the receiving voltage at the installation site of the equipment.

[0008]

SUMMARY OF THE INVENTION The present invention is directed to a gas-insulated electrical device in which components of the electrical device including a main circuit conductor to which a received voltage is applied are housed in a metal container filled with an insulating gas. The present invention relates to a device for detecting a receiving voltage.

A power receiving voltage detection device to be improved by the present invention is a power detection electrode disposed in a metal container so as to face a main circuit conductor, and a power detection electrode disposed outside the metal container and having one end grounded.
At the other end, a secondary coil is wound around a current detection coil connected to the voltage detection electrode through the center conductor of an insulating bushing that penetrates the wall of the metal container in an airtight manner, and an iron core having a magnetic path linked to the current detection coil. An ammeter for detecting a minute current flowing through the current detection coil through the current transformer having a turned configuration, and a grounding circuit through the capacitance between the main circuit conductor and the detection electrode and the current detection coil. The power supply voltage applied to the main circuit conductor is detected by detecting the leakage current flowing through the main circuit conductor.

According to the present invention, the number of windings of the current detecting coil is adjusted in the above-described receiving voltage detecting device so that the value displayed on the ammeter can be used as it is as the value indicating the receiving voltage. It is necessary to connect a variable resistor in parallel with the current detection coil and adjust the resistance value of the variable resistor so that the value displayed on the ammeter can be used as it is as the value indicating the receiving voltage. Features.

In order that the numerical value displayed on the ammeter can be used as it is as the numerical value indicating the receiving voltage, it is, of course, necessary to appropriately select the display unit of the ammeter. . For example, if the receiving voltage is 66
When the current detected by the ammeter is 66000 [μA] at [kV], the unit of display is [μA].
Instead of [mA], the display of the ammeter is 6
6 [mA].

[0012] With the above configuration, the received voltage can be known simply by reading the ammeter display while changing the unit, so that the operator can easily determine the received voltage at the installation site of the gas-insulated electrical equipment. Will be able to know.

[0013] In order to improve the safety of the gas-insulated electrical equipment during maintenance and inspection, the magnitude of the receiving voltage can be determined from the reading of a measuring instrument, and at the same time, the electrical equipment receives power. It is preferable to display an indication that the device is in a power receiving state so that the operator can immediately detect that the device is receiving power.

For this purpose, it is preferable to connect a light emitting display element (light emitting diode, neon tube, etc.) which emits light when a current flows, in series with the current detecting coil.

In order to secure the safety of operations such as maintenance and inspection, it is preferable to provide a grounding switch for grounding the center conductor of the bushing as required outside the metal container.

[0016]

FIG. 1 shows an embodiment of the present invention, in which 1 is a metal container of a gas-insulated electric device. The components of the electrical equipment including the main circuit conductor (conductor through which the main circuit current flows) 2 are housed inside the metal container 1. The components contained in the metal container differ depending on the configuration of the electric device. For example, in the case of a gas insulated switchgear constituting a switchgear circuit of an electric substation such as a substation, a circuit breaker,
Switchgear such as disconnectors and earthing switches, connection conductors connecting the devices, bus conductors, or cable heads connecting the terminals of the power cables, etc. are appropriately divided as components into a plurality of metal containers. Either stored or collectively stored in a single metal container. The metal container 1 is maintained at a ground potential, and an insulating gas (usually SF ₆ gas) is sealed therein at a predetermined pressure.

An electrode 3 for electric detection is provided in the metal container 1, and the electrode 3 for electric detection is opposed to the main circuit conductor 2 with a predetermined gap therebetween.

In the present invention, the main circuit conductor 2 facing the voltage detection electrode 3 may be a conductor through which a main circuit current flows, and its shape is arbitrary, but the area facing the voltage detection electrode 3 is sufficient. Preferably, the shape is such that the shape can be taken. The detection electrode 3 is formed in an appropriate shape in accordance with the shape of the main circuit conductor 2 so that the area facing the main circuit conductor 2 can be sufficiently large.

In the illustrated example, the main circuit conductor 2 is formed in a columnar or tubular shape. The voltage detection electrode 3 is formed in a flat plate shape, and is arranged to face the main circuit conductor 2 with its plate surface parallel to the central axis of the main circuit conductor 2.

When the main circuit conductor 2 is formed in a columnar or tubular shape, the detection electrode 3 does not necessarily need to be formed in a flat plate shape, but may be curved to form a recess on the main circuit conductor 2 side, for example. (For example, a shape curved along a cylindrical surface extending substantially concentrically with the main circuit conductor 2).

In the example shown in the figure, an insulating bushing is formed in a state where the wall portion of the metal container 1 is airtightly penetrated (an insulator attached in a state penetrating the wall portion of the container and a center conductor which is airtightly penetrated the center portion thereof). The insulating electrode 4 is attached to the end of the center conductor 4a of the insulating bushing 4 located in the metal container 1, and the electrode 3 for electrical detection is electrically and mechanically connected and supported.

An air-core current detection coil 5 wound N turns (N = several hundreds to thousands) is disposed outside the metal container 1. One end of the current detection coil 5 is grounded through a ground wire 6. I have. The other end of the current detection coil 5 is connected to the detection electrode 3 through the center conductor 4 a of the insulating bushing 4.

A grounding switch 7 is arranged outside the metal container 1, and the grounding switch 7 is connected between the center conductor 4 a of the insulating bushing 4 and the ground. A variable resistor 8 is connected in parallel to both ends of the current detection coil 5.

An ammeter 9 with a current transformer is attached to the current detection coil 5. The ammeter 9 includes a current transformer CT having an iron core 901 having a magnetic path interlinked with the current detection coil 5 and a secondary coil 902 wound around the iron core 901.
A display instrument 90 for amplifying the output of the secondary coil 902 of the current transformer and displaying the current value of the current flowing through the current detection coil 5
3 is provided. The illustrated ammeter 9 has an iron core 90.
A well-known clamp-type micro-ammeter which is formed so as to be openable and closable and forms a closed magnetic circuit by clamping a core through which a current to be measured flows inside a core 901. The display instrument 903 digitally displays the current value. This ammeter 9
As shown in FIG. 2, the iron core 901 is attached in a state where it is linked with the current detection coil 5.

The ammeter 9 may be always attached to the current detection coil 5, or may be attached to the current detection coil 5 only when necessary. The display of the ammeter 9 may be an analog type or a digital type.

The electrode 3 for electric detection and the insulating bushing 4
The current detection coil 5, the variable resistor 8, the ammeter 9, and the grounding switch 7 constitute a receiving voltage detection device according to the present invention. When the received voltage is detected by using the received voltage detection device, the grounding switch 7 is opened to bring the power detection electrode 3 into the non-ground state, and between the main circuit conductor 2 and the power detection electrode 3. The minute leakage current Ileak flowing to the ground circuit through the current detection coil 5 due to the generated electrostatic induction is detected by the ammeter 9. In this case, the current transformer provided in the ammeter 9
Since the current Ict given by Ict = Ileak × N is detected, the leakage current Ileak is apparently amplified N times and detected. Therefore, by sufficiently increasing the number of turns N of the current detection coil 5, the leakage current can be detected with high sensitivity.

In the receiving voltage detector shown in FIG. 1, the resistance of the variable resistor is adjusted so that the value displayed on the ammeter can be used as it is as the value indicating the receiving voltage. By adjusting the resistance value of the variable resistor 8 in this manner, the magnitude of the receiving voltage can be known by looking at the display of the ammeter 9 and reading only the unit.

For example, when the receiving voltage of the gas insulated switchgear is 7
In the case of 7 [kV], the capacitance between the main circuit conductor 2 and the detection electrode 3 is 2 [pF], and the frequency f of the receiving voltage is 50.
[Hz], the main circuit conductor 2 and the voltage detection electrode 3
The leakage current Ileak flowing through the capacitance between
leak = 77000 / ｛1 / (2π × 50 × 2 × 10 -1
2)｝ = 48 [μA]. Here, assuming that the resistance value of the variable resistor 8 is infinite and the number of turns N of the current detection coil 5 is 2000 turns, the current Ict detected by the ammeter 9 is Ict = 48 × 10 ⁻⁶ × 2000 = 96.8
[MA], and the received voltage value cannot be directly known from this display. Therefore, in the present invention, the variable resistor 8
Is adjusted to adjust the magnitude of the current shunted through the variable resistor 8 so that the display of the ammeter 9
7 [mA]. With such adjustment, the magnitude of the charging voltage can be known by reading the display of the ammeter while replacing the unit [mA] with [kV].

Similarly, when the receiving voltage is 66 [kV] and the capacitance between the main circuit conductor 2 and the detection electrode 3 is 3 [p
F], assuming that the frequency f of the received voltage is 50 [Hz], the leakage current Ileak flowing through the capacitance between the main circuit conductor 2 and the detection electrode 3 is 62 [μA]. Assuming that the number of turns of the current detection coil 5 is 2000 turns, the current value Ict detected by the ammeter when the resistance value of the variable resistor 8 is infinite is 124.4 [mA]. In this case, the resistance value of the variable resistor 8 is adjusted so that the display of the ammeter is 66 [mA].

When the number of turns of the current detection coil is increased, the capacitance between turns of the coil becomes nonnegligible, and a detection error occurs. It is preferable to take the following measures. For example, as shown in FIG. 5A, when the current detection coil is curved so that the turns of the current detection coil are arranged in a radial or fan shape, the capacitance between the turns can be reduced. it can. Further, as shown in FIG. 5B, the cross-winding of the current detection coil 5 can also reduce the capacitance between turns.

FIG. 3 shows another embodiment of the receiving voltage display device according to the present invention. In this embodiment, a light emitting display element 10 which emits light when a current flows is connected in series to a current detecting coil 5. It is connected to the. In the illustrated example, a light emitting diode is used as the light emitting display element 10. When the light emitting display element is connected in series to the current detection coil in this way, the light emission of the light emitting display element makes it possible to immediately know that the electric device is in the power receiving state, and the operator may mistakenly use the bushing. It is possible to prevent an electric shock accident from being caused by touching the center conductor 4a or the like 4. The light emitting display element 10 is not necessarily limited to a light emitting diode, and a neon tube or the like may be used as the light emitting display element 10.

In a gas-insulated electric device, a voltage detecting device of a capacitance division type is often provided in order to detect a voltage of a main circuit conductor in a metal container. The voltage detecting device of the capacitance-divided type is connected between a grounding electrode arranged opposite to the main circuit conductor in the metal container, a conductor drawn out of the metal container from the detecting electrode, and ground. And a capacitor voltage dividing circuit for supplying the divided voltage output of the capacitor voltage dividing circuit to an instrument provided on a monitor panel or the like. When such a voltage detecting device of the capacitance division type is provided in the gas insulated electric equipment, the current detection coil is inserted in series with the capacitor voltage dividing circuit of the detection device, so that the current detection coil is inserted. The receiving voltage detection device according to the present invention can be simply configured.

FIG. 4 shows an example in which the present invention is applied to a case where a capacitance-divided voltage detecting device is provided. In FIG. 4, reference numeral 11 denotes a plurality of capacitors connected in series. The voltage dividing output Vo of the capacitor voltage dividing circuit 11 is provided to an indicating instrument of a monitoring panel. As described above, when the voltage detecting device of the capacitive voltage dividing type is provided, the current detecting coil 5 is connected between the ground side terminal of the capacitor voltage dividing circuit 11 and the ground.
Is inserted, a variable resistor 8 is connected in parallel with the current detection coil 5, and the resistance value of the variable resistor 8 is adjusted as described above. Can be configured.

In the above example, the variable resistor 8 is connected in parallel to the current detecting coil 5 and the resistance value of the variable resistor 8 is adjusted, so that the value displayed on the ammeter is changed to a value indicating the receiving voltage. However, by adjusting the number of turns of the current detection coil 5 without connecting the variable resistor 8, the value displayed on the ammeter may be made to match the value indicating the receiving voltage. Good.

In the above example, a clamp type current transformer attached to the ammeter is used. However, when a current meter is permanently installed, it is necessary to use an ammeter having a clamp type current transformer. Instead, it is possible to use an ammeter which measures the current through a current transformer in which a secondary coil is wound around a closed magnetic circuit core interlinking with the current detection coil.

[0036]

As described above, according to the present invention, by adjusting the number of turns of the current detecting coil, or by adjusting the resistance value of the variable resistor connected in parallel to the current detecting coil, Since the numerical value displayed on the ammeter can be used as it is as the numerical value indicating the receiving voltage, there is an advantage that the operator can easily know the magnitude of the receiving voltage at the installation site of the gas insulated electric device. .

Further, according to the present invention, the display of the ammeter can be made to match the display of the receiving voltage only by adjusting the number of turns of the current detecting coil or adjusting the resistance value of the variable resistor connected in parallel to the current detecting coil. The received voltage can be displayed without providing an arithmetic unit for converting the current value to the voltage value, and the configuration of the received voltage detection device can be simplified.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a main part showing a configuration example of a received voltage detection device according to the present invention.

FIG. 2 is an explanatory diagram showing a state in which an ammeter is attached to a current detection coil in the receiving voltage detection device of FIG.

FIG. 3 is a configuration diagram of a main part showing another configuration example of the received voltage detection device according to the present invention.

FIG. 4 is a configuration diagram of a main part showing still another configuration example of the reception voltage detection device according to the present invention.

FIGS. 5A and 5B are perspective views each showing a preferred configuration example of a current detection coil used in the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Metal container 2 Main circuit conductor 3 Electrode detection electrode 4 Insulation bushing 5 Current detection coil 6 Ground wire 7 Ground switch 8 Variable resistor 9 Ammeter

Claims (4)

[Claims] 1. A main circuit in a metal container of a gas-insulated electric device, wherein components of the electric device including a main circuit conductor to which a received voltage is applied are housed in a metal container filled with an insulating gas. An electrode for electric detection arranged opposite to the conductor, and one end grounded at the outside of the metal container, and the other end passes through a center conductor of an insulating bushing that air-tightly penetrates a wall of the metal container. A current detecting coil connected to an electrode, and a current for detecting a small current flowing through the current detecting coil through a current transformer having a configuration in which a secondary coil is wound around a core having a magnetic path interlinking with the current detecting coil. A leakage current flowing through a ground circuit through the capacitance and the current detection coil between the main circuit conductor and the voltage detection electrode, and the leakage current is applied to the main circuit conductor by detecting the leakage current with the ammeter. In the receiving voltage detection device for a gas-insulated electrical device that detects the receiving voltage, the number of turns of the current detection coil is adjusted so that the value displayed on the ammeter can be used as it is as a value indicating the receiving voltage. A receiving voltage detecting device for gas-insulated electrical equipment, comprising: 2. The main circuit in a metal container of a gas-insulated electric device in which components of the electric device including a main circuit conductor to which a received voltage is applied are housed in a metal container filled with an insulating gas. An electrode for electric detection arranged opposite to the conductor, and one end grounded at the outside of the metal container, and the other end passes through a center conductor of an insulating bushing that air-tightly penetrates a wall of the metal container. A current detecting coil connected to an electrode, and a current for detecting a small current flowing through the current detecting coil through a current transformer having a configuration in which a secondary coil is wound around a core having a magnetic path interlinking with the current detecting coil. A leakage current flowing through a ground circuit through the capacitance and the current detection coil between the main circuit conductor and the voltage detection electrode, and the leakage current is applied to the main circuit conductor by detecting the leakage current with the ammeter. In a receiving voltage detecting device for a gas insulated electric device that detects a receiving voltage, a variable resistor is connected in parallel to the current detecting coil, and a numerical value displayed on the ammeter is used as a numerical value indicating the receiving voltage. A receiving voltage detecting device for a gas-insulated electric device, wherein a resistance value of the variable resistor is adjusted so as to be used. 3. The receiving voltage for gas-insulated electric equipment according to claim 1, wherein a light-emitting display element that emits light when a current flows is connected in series to the current detection coil. Detection device. 4. The gas-insulated electric device according to claim 1, wherein a grounding switch for grounding a center conductor of the bushing is provided outside the metal container. Receiving voltage detection device.