JP2003232815A - Optical current measuring device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To elongate the service life of a sensor, and to measure a current flowing in an energizing conductor in gas insulating equipment compactly and highly accurately. <P>SOLUTION: In the gas insulating equipment, an insulating gas is filled in a closed tank formed by connecting, through interposed metal rings, respective metal flanges having a plurality of tubular tanks on each connection end, and the energizing conductor arranged in the longitudinal direction is supported, and the circumferential part of an insulating spacer for gas-partitioning the inside of the closed tank is interposed and fixed on the inner circumferential side of the metal rings between respective metal flanges. In the equipment, an insulating ring is disposed between one side of the metal flange and the metal ring to thereby insulate the interval between the metal flanges where the insulating spacer is interposed, and a circular case for storing an optical fiber sensor for measuring the current flowing in the energizing conductor based on the polarized state received by light circulating around the energizing conductor and passing through it is provided, supported on one side, on a support member mounted on the metal flange. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical current measuring device for measuring a current flowing through a power device or power system of a substation or a power plant using an optical transformer.

[0002]

2. Description of the Related Art In a gas insulated switchgear such as a circuit breaker or a disconnector, an optical current measuring device using an optical transformer is adopted as a means for measuring a current flowing in an electric circuit. This optical current measuring device receives Faraday optical rotation by transmitting light incident from a light source to an optical fiber sensor that is provided around the conductor, and outputs a light intensity signal of two orthogonal components from this Faraday optical rotation. This is to take out, convert this into an electric signal and measure the value of the current flowing through the conductor.

FIG. 4 is a sectional view showing a structural example of a gas-insulated switchgear provided with such an optical fiber sensor.

In FIG. 4, 1a and 1b are tubular tanks in which a central conductor 2 is arranged along the longitudinal direction, and these tubular tanks 1a and 1b have metal flanges 3a and 3b at their connecting ends. In between, an insulating spacer 4 for supporting the central conductor 2 and partitioning an insulating gas, a metal ring 5 provided on the outer peripheral surface side of the insulating spacer 4, one end surface side of the outer peripheral portion of the insulating spacer 4 and the metal ring 5, respectively. The sensor portions 15 are respectively inserted in and are fastened integrally with the bolts 7.

The sensor portion 15 includes an annular insulating member 16 arranged on the inner diameter side of the metal flange 3a, an annular metal member 17 surrounding the outer periphery thereof, and an outer peripheral surface of the annular insulating member 16 and an inner surface of the annular metal member 17. It is composed of an optical fiber sensor 12 which is arranged around the center conductor 2 a plurality of times in between.

It should be noted that both ends of the annular insulating member 16 sandwiched between the one metal flange 3a and the annular metal member 17 and both end faces of the outer peripheral portion of the insulating spacer 4 sandwiched between the other metal flange 3b and the annular metal member 17 are overlapped. The rings 6 are respectively inserted to keep the inside of the annular tank airtight.

[0007]

As described above, the sensor unit 1
In the optical current measuring device having a structure in which 5 is arranged at the flange connection portion of the annular tanks 1a and 1b, the vibration generated when the circuit breaker or disconnector of the gas insulated switchgear (not shown) is opened and closed in the sensor portion 15 When transmitted through 1a, 1b and the metal flanges 3a, 3b, the optical fiber sensor 12 is affected by vibration, which is an error factor during current measurement. In particular, when an interference type optical current measurement sensor (Sagnac type optical CT sensor) is adopted in the sensor unit, there is a problem that the sensor is easily affected by vibration acceleration, and thus current cannot be measured with high accuracy. It was

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide an optical current measuring device capable of highly accurate measurement as a sensor support structure which is hardly affected by vibration.

[0009]

In order to achieve the above object, the present invention constitutes an optical current measuring device by the following means.

The invention corresponding to claim 1 is to fill an insulating gas into a sealed tank formed by connecting metal flanges having a plurality of tubular tanks at respective connection end portions with each other through a metal ring, and A conductive conductor is arranged in the longitudinal direction, and the outer peripheral portion of an insulating spacer that supports the conductive conductor and divides the gas in the closed tank is attached to the inner peripheral side of the metal ring between the metal flanges. In a gas insulation device, an insulating ring is provided between one side of the metal flange and the metal ring to insulate between the metal flanges sandwiching the insulating spacer, and to circulate and transmit around the current-carrying conductor. An optical fiber sensor for measuring the current flowing through the current-carrying conductor based on the polarization state associated with the Faraday effect received by light is housed in an annular case. Provided in the over scan is cantilevered support member mounted on the outer circumferential surface of the one metal flange.

The invention according to claim 2 is to fill an insulating gas into a closed tank, which is formed by inserting and connecting an insulating flange between metal flanges having a plurality of tubular tanks at respective connection ends, In a gas-insulated device in which a current-carrying conductor is arranged in its longitudinal direction, a current flowing through the current-carrying conductor flows through the current-carrying conductor based on a polarization state associated with a Faraday effect of light passing through the current-carrying conductor and passing therethrough. An optical fiber sensor for measuring an electric current is housed in an annular case, and the case is cantilevered and supported by a supporting member attached to the outer peripheral surface of the one metal flange.

According to a third aspect of the present invention, in the optical current measuring device according to the first or second aspect of the present invention, the support member has an insulating ring-shaped case accommodating an optical fiber sensor having an elastic force. Composed of the body.

According to a fourth aspect of the invention, in the optical current measuring device according to the first or second aspect of the invention, the annular case accommodating the optical fiber sensor has an airtight structure and dry air inside. Filled with nitrogen / inert gas or kept in vacuum.

According to a fifth aspect of the present invention, in the optical current measuring device according to the fourth aspect of the present invention, the annular case is made of metal and is hermetically sealed by welding a cover to an opening for housing the fiber sensor. The seal is applied.

According to a sixth aspect of the present invention, in the optical current measuring device according to any one of the first to fifth aspects of the present invention, a connecting member for electrically connecting the metal flanges to each other is provided. Set up.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view showing a first embodiment of an optical current measuring device according to the present invention, and the same parts as those in FIG.

In FIG. 1, reference numerals 1a and 1b denote tubular tanks in which a conducting conductor (hereinafter referred to as a central conductor) 2 is arranged at a center position of the inside along the longitudinal direction.
Are metal flanges 3a and 3b at their respective connection ends
An insulating spacer 4 for supporting the central conductor 2 and partitioning an insulating gas is interposed between the insulating spacer 4 and a metal ring 5 provided on the outer peripheral surface side of the insulating spacer 4, and between the metal flange 3a and the metal ring 5 on one side. An insulating ring 8 is provided, and these are integrally fastened by a bolt 7. Therefore, the metal flanges 3a and 3b are electrically insulated from each other by the insulating ring 8 so that the induction current due to the magnetic flux generated from the central conductor 2 does not flow through the metal flange 3a, the metal ring 5 and the metal flange 3b.

O-rings 6 are inserted into both end surfaces of the insulating spacer 4 which contacts the metal flanges 3a and 3b.
The inside of the tank is kept airtight.

In such a flange connection portion of the annular tank, a plurality of insulators 9 having elastic force are respectively arranged on the outer peripheral surface of the metal flange 3b on the side of the one tubular tank 1b, and the optical fiber is attached to the insulator 9. An annular case 10 in which the sensor 12 is housed so as to circulate around the central conductor 2 is electrically insulated and cantilevered.

In this case, the annular case 10 is arranged at an appropriate distance from the outer peripheral surface of the metal ring 5.

On the other hand, the opening of the annular case 10 accommodating the optical fiber sensor 12 is closed by a metal cover 11 by, for example, laser welding in order to keep the internal space airtight, and the inside of the case 10 is filled with dry air. Filled with nitrogen / inert gas or kept in vacuum.

With such a structure, the annular case 10 accommodating the optical fiber sensor 12 is elastically attached to the outer peripheral surface of the metal flange 3b without being incorporated into the flange connection end of the annular tank such as the switchgear. Since it has a structure in which the vibration of the circuit breaker or the disconnecting switch is difficult to be transmitted by being cantilevered by the insulator 9 having, the vibration generated when the circuit breaker or the disconnecting switch is opened and closed is extremely attenuated and transmitted to the optical fiber sensor 12. It In this case, the vibration of the circuit breaker or the disconnecting switch is similar to the shock vibration generated at a high frequency in a very short time, but the peak value of this shock vibration can be effectively damped by the support member 9 having an elastic force. You can A specific example of the insulator 9 used as the support member is silicone rubber. Generally rubber is an effective elastic body that retains the deformability of the case while damping the impact, but with silicone rubber,
Further, it is also excellent in deterioration resistance.

Therefore, even if a sensor such as the Sagnac type optical CT sensor which is easily influenced by the vibration acceleration is adopted, the error due to the vibration can be suppressed to the minimum and the current can be measured with high accuracy.

Further, in the space between the optical fiber sensor 12 and the central conductor 2, even if the metal ring 5 is provided on the outer peripheral surface side of the insulating spacer 4, the metal flanges 3a and 3b are provided.
They are electrically insulated from each other by an insulating ring 8 and an induced current due to a magnetic field generated from the central conductor 2 does not flow through the metal flange 3a, the metal ring 5 and the metal flange 3b. There is no error factor due to the effect on the polarization state associated with the effect, and high-precision current measurement can be performed.

Furthermore, since the atmosphere around the optical fiber sensor 12 is protected from components such as moisture that deteriorate the fiber, it is possible to measure the current with high accuracy and to extend the life of the optical fiber sensor 12.
Further, since the cover 11 of the ring-shaped case 12 has an airtight sealing structure which is hermetically sealed by laser welding without using an O-ring or the like, the size of the case can be made very compact.

Here, the reason why laser welding is adopted is that the case is heated in ordinary resistance welding and the like, which deteriorates or damages the optical fiber sensor 12, but in the case of laser welding, the temperature is lower than that of the base material. This is because welding is possible.

FIG. 2 is a sectional view showing a second embodiment of the present invention. The same parts as those in FIG. 1 are designated by the same reference numerals and the description thereof will be omitted. Only different points will be described here.

In the second embodiment, as shown in FIG. 2, the metal flanges 3a and 3b are electrically connected by a conductive cover or a shunt bar 14, and the other portions are the first. The configuration is similar to that of the above embodiment.

With such a structure, it is suitable as an optical current measuring device for a gas-insulated switchgear of a multipoint grounding system. That is, in the first embodiment, the tubular tanks are electrically insulated from each other by the insulating spacers 4 and therefore are suitable for the gas insulated switchgear of the single-point grounding system. It is not suitable for gas-insulated switchgear of multi-point grounding system that needs to be electrically connected.

However, in the second embodiment, since the tubular tanks of the gas insulated switchgear can be electrically connected by the conductive cover or the shunt bar 14, the gas insulated switchgear of the multipoint grounding system is suitable. is there. It is also suitable for a gas-insulated switchgear of a single-point ground system.

FIG. 3 is a sectional view showing a third embodiment of the present invention. The same parts as those in FIG.

In FIG. 3, 1a and 1b are tubular tanks in which the central conductor 2 is arranged along the longitudinal direction, and these tubular tanks 1a and 1b are metal flanges 3a, which are provided at their respective connection ends. An annular insulating flange 13 between 3b
These are integrally fastened by bolts 7 by inserting.

The O-rings 6 are inserted into both end portions of the insulating flange 13 which is in contact with the metal flanges 3a and 3b to keep the inside of the tank airtight.

Even at the flange connection end of the annular tank using the insulating flange 13, the metal flanges sandwiching the insulating flange 13 can be electrically insulated from each other, so that the insulating ring 8 in the first embodiment is unnecessary. Becomes

In the flange connection portion of the annular tanks 1a and 1b having such a structure, a plurality of insulators 9 having elastic force are arranged on the outer peripheral surface of the metal flange 3b of the one tubular tank 1b, respectively, and the insulation is obtained. An annular case 10 accommodating an optical fiber sensor 12 is supported by a body 9 in a cantilevered manner, and is electrically insulated and attached.

In this case, the annular case 10 is arranged at an appropriate distance from the outer peripheral surface of the insulating flange 13.

On the other hand, the opening of the annular case 10 accommodating the optical fiber sensor 12 is closed by a metal cover 11 by laser welding in order to keep the internal space airtight, and the inside of the case 10 is dry air / nitrogen. • Filled with an inert gas or kept in a vacuum.

Even with such a structure, it is possible to obtain the same effects as those of the first embodiment.

Also in this embodiment, the metal flanges 3a and 3b may be electrically connected by a conductive cover or a shunt bar 14 as in the second embodiment. Needless to say.

[0041]

As described above, according to the present invention, since the sensor support structure is less susceptible to the vibration of the circuit breaker or the disconnecting switch of the gas switchgear, the life of the sensor can be extended. At the same time, it is possible to provide an optical current measuring device that is compact and can measure with high accuracy.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a flange connection part of an annular tank to which a first embodiment of an optical current measuring device according to the present invention is applied.

FIG. 2 is a cross-sectional view showing a flange connection portion of an annular tank to which the second embodiment of the optical current measuring device according to the present invention is applied.

FIG. 3 is a sectional view showing a flange connection portion of an annular tank to which an optical current measuring device according to a third embodiment of the present invention is applied.

FIG. 4 is a cross-sectional view showing a flange connection portion of an annular tank to which a conventional optical current measuring device is applied.

[Explanation of symbols]

1a, 1b ... annular tank 2 ... Central conductor 3a, 3b ... Metal flange 4 ... Insulating spacer 5 ... Metal ring 6… O-ring 7 ... bolt 8 ... Insulation ring 9 ... Insulator 10 ... Case 11 ... Cover 12 ... Optical fiber cable 13 ... Insulation flange

Claims (6)

[Claims] 1. An insulating gas is filled in a sealed tank formed by connecting metal flanges having a plurality of tubular tanks at their respective connection end portions with a metal ring interposed therebetween, and a conducting conductor is provided in the longitudinal direction thereof. A gas-insulated device in which an outer peripheral portion of an insulating spacer that is arranged and supports the current-carrying conductor and that divides gas in the closed tank is inserted and attached to an inner peripheral side of the metal ring between the metal flanges, An insulating ring is arranged between one side of the metal flange and the metal ring to insulate between the metal flanges sandwiching the insulating spacer, and circulates around the current-carrying conductor, and is in a polarization state in which the transmitted light receives. Based on this, an optical fiber sensor for measuring the current flowing through the current-carrying conductor is housed in an annular case, and this case is attached to the outer peripheral surface of the one metal flange. Optical current measuring device was kicked were the support member cantilevered, characterized in that provided. 2. A closed tank, which is formed by connecting an insulating flange between metal flanges having a plurality of tubular tanks at respective connection ends, is filled with an insulating gas, and a conducting conductor is provided in a longitudinal direction thereof. In the arranged gas-insulated equipment, an optical fiber sensor for measuring the current flowing through the current-carrying conductor based on the polarization state in which the current flowing through the current-carrying conductor is circulated around the current-carrying conductor and the light passing therethrough is received. An optical current measuring device, characterized by being housed in a case, and being cantilevered by a supporting member attached to the outer peripheral surface of the one metal flange. 3. The optical current measuring device according to claim 1 or 2, wherein the supporting member is formed of an insulator having an elastic force in an annular case accommodating an optical fiber sensor. An optical current measuring device. 4. The optical current measuring device according to claim 1, wherein the annular case accommodating the optical fiber sensor has an airtight structure, and the inside is dry air / nitrogen.
An optical current measuring device characterized by being filled with an inert gas or being kept in a vacuum state. 5. The optical current measuring device according to claim 4, wherein the annular case is made of metal and is hermetically sealed by welding a cover to an opening for housing the fiber sensor. Optical current measuring device. 6. The optical current measuring device according to claim 1, further comprising: a connecting member for electrically connecting the metal flanges to each other. Current measuring device.