JPS6396566A - Gas insulating current transformer - Google Patents

Abstract

PURPOSE:To remarkably improve the measurement accuracy of a current transformer by providing a heat transfer element consisting of a heat pipe provided with a cooling fin on its one end, etc., on the inside of a conductor for passing through a shielding case. CONSTITUTION:In a gas insulating current transformer, even when a current flaws to a conductor 22v and the temperature of a conductor part rises, its heat is emitted to an adjacent conductor 60 connected to the conductor 22v by a heat transfer element 51 provided on the inside of the conductor 22v. Also, this emitted heat is diffused to the outside of the adjacent conductor 60 by a cooling fin 52 provided on the end part of the heat transfer element 51 and a projecting part 61 formed in the adjacent conductor. In this way, even if a current flows to conductors 22u-22w and the temperature of the conductor part is varied, its heat can suppress to the minimum a temperature change in the vicinity of a magneto-optical field sensor 23 provided in the periphery of the conductors 22u-22w by the heat transfer element 51, and prevents an output error from being generated in the current transformer.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a gas-insulated current transformer, and in particular, a gas-insulated current transformer that is equipped with an optical magnetic field sensor and its detection device, and that transmits light between them. It pertains to a gas insulated current transformer having the following configuration.

(Prior Art) Conventionally, a gas insulated current transformer used in a gas insulated switchgear has been configured with an iron core type current transformer core made by winding a coil around a silicon steel plate.

Such a conventional gas insulated current transformer will be described with reference to FIG. 2, taking as an example a gas insulated current transformer used in a three-phase disposable type gas insulated switchgear.

Inside the cylindrical tank 1 are three-phase conductors 2u of U, V, and W phases.
~2W is installed. Insulating spacers 3 are provided before and after the tank 1, and the conductors 2u to 2W are supported by these spacers. The tank 1 is divided into front and rear parts perpendicular to its axis, and consists of a tank 1a at the front having the original diameter and a tank 1b at the rear having a diameter increased by the dimension of the current transformer core 4. has been done. Current transformer cores 4 are installed on the extensions of the conductors 2u to 2w at the inner end of the tank 1b, respectively. A support plate 5 is provided in front of the current transformer core 4 (that is, at the end of the rear tank 1b),
An insulating shield 6 is connected to the inside of the current transformer core 4.
are provided to support the current transformer core 4 and insulate it from the conductors 2u to 2w. Furthermore, a sealed terminal 7 is provided at the bottom of the tank 1 for drawing out the current from the current transformer core 4.

By the way, in such a gas-insulated three-phase current transformer, three
Because the current transformer core is heavy, the supports, support plates, insulation shields, etc. required for it are quite large, and in order to install these in three locations, the equipment becomes multi-fiber and larger, and even AAA In addition, since the current transformer core is cocoa and can only be used for one purpose, multiple cores are required for relays, measurements, etc., which not only causes the size to increase, but also increases the cost. It ends up being expensive.

In view of these shortcomings, measurement technology using optical fibers, which have excellent characteristics such as small diameter, insulation, non-induction, and environmental resistance, has recently attracted attention. Attempts are being made to construct vessels.

FIG. 3 shows the configuration of a gas insulated current transformer using such an optical magnetic field sensor.

In FIG. 3(B), in the tank 21 of the breaker,
Three-phase conductors 22u to 22W are arranged, and these conductors 2
Connection portions 22a and 22b are formed at both ends of 2u to 22W for connection to adjacent conductors disposed within the gas insulated switchgear. Approximately at the center of these conductors 22u to 22W, there is a shield case 2 in which a magneto-optical field sensor 23, which is attached so as to go around each conductor, can be housed therein.
6 is installed. This shield case 26 is made of copper.
It is made of a conductive material such as aluminum or a combination of such a conductive material and a magnetic material such as a silicon steel plate, and also functions as an electric field shield. Further, this shield case 26 is composed of three parts: a case 26a, a 7-ring 26b, and an insulating ring 26c, and one of the two conductor penetration parts of the shield case 26 is welded so that the conductor is connected to the conductor 26a. are fixed, and the other penetrating portion is connected to the case 26a via the insulating ring 26c and the lid 26b.
The conductor is fixed to.

In addition, as shown in FIG. 3 (A>), the tank 21 has three
Opening portions 21u, 21v, and 21w are formed at equal intervals in the circumferential direction, and the support container 2 is attached to the flanges of the opening portions.
9 is removably fixed with a bolt. An insulating cylinder 2 for supporting the shield case 26 and the conductors 22u to 22W is provided between the support container 29 and the shield case 26.
8 is provided perpendicularly to each conductor 22u to 22W. Furthermore, gas seals using O-rings 35 to 41 are provided at the connection parts of the conductor 22, shield case 26, insulating tube 28, support container 29, lid 34 disposed on the outside of the support container, etc. is an airtight conductor unit, and an insulating gas such as SF6 gas with the same pressure as in the tank 21 is sealed in this unit, and an adsorbent case (not shown) and a density switch are installed to manage moisture and gas pressure for each phase unit. etc.

On the other hand, inside the shield case 26, an optical magnetic field sensor 23 consisting of 7 Radhe elements is fixed by a support base 25 so as to circulate around each of the conductors 22u to 22W and not to come into contact with each of the conductors 22u to 22W. There is. This optical magnetic field sensor 23 has a substantially square cross section with only a total reflection surface, a reflection mirror, and the like.

The optical magnetic field sensor 23 is made of glass such as lead glass that generates a Faraday rotation angle depending on the strength of the magnetic field, and is constructed by combining a Faraday element with a total reflection surface on each corner and a reflecting mirror, so that the light transmitted through the Faraday element is The structure is such that the light goes around a conductor, and the optical path is made to reciprocate using a reflective mirror, making it possible to perform highly accurate and sensitive measurements without being affected by external magnetic fields.

In addition, holes 27 and 30 for light passage are formed in opposing surfaces of the shield case 26 and the support container 29, which are disposed at opposing positions with a space in the insulating cylinder 28 interposed therebetween.

Furthermore, within the support container 29, a light emitting/receiving section 32 consisting of a lens, a polarizer, an analyzer, etc. is attached to the support container 2 by a support member 31.
The light emitting/receiving section 32 and the first entrance/exit surface 24 of the optical magnetic field sensor 23 are arranged to face each other on the optical axis of the optical path, and light is transmitted through the space within the insulating cylinder 28. It is configured so that

Further, a lid 34 attached to the support container 29 is provided with a sealed terminal 33, and the light emitting/receiving section 32 and the detection bag @44 provided outside the tank 21 are connected via the sealed terminal 33 for light transmission and detection. They are connected by optical fibers 42 and 43 for light reception.

In the gas insulated current transformer having the above configuration, the optical magnetic field sensor 23 is placed inside the shield case 26 which also serves as an electric field shield, so that the optical magnetic field sensor 923 can be prevented from being affected by external magnetic fields. , optical magnetic field sensor 2
3 can also be prevented from being exposed to high electric fields.

Furthermore, since the magneto-optical field sensor 23 is fixed in the shield case 26 by the support stand 25 and is configured so as not to come into contact with the conductor 22, expansion, contraction, bending, etc. of the conductor have no effect on the optical characteristics of the magneto-optical field sensor 23. It is also possible to prevent the optical axis from being shifted.

In addition, the conductor 22, the shield case 26, the insulating tube 28,
Two support containers, O-rings 35 at each connection part of the lid 34, etc.
- 41 are provided to form a gas-tight integral unit, and the optical magnetic field sensor 23,
By housing optical parts such as the light emitting/receiving section 32, it is possible to prevent flashes of arcs, etc. that occur near current transformers, gaseous and solid decomposition products of insulating gas that occur when arcs are interrupted in gas-insulated switchgear, or during ground faults. It is also possible to protect these optical components from

However, in the conventional gas insulated current transformer having the above configuration, when current flows through the conductors 22U to 22W of each phase, the temperature around these conductors increases. Accordingly, the temperature distribution also changes in the vicinity of the optical magnetic field sensor 23, which is attached so as to go around each conductor. As a result, the optical parameters of the optical elements such as the Faraday element constituting the magneto-optical field sensor 23 become non-uniform, and the degree of polarization of the light transmitted through the Faraday element changes, as shown in FIG. This method has the disadvantage that the output error of the flow meter increases, making it impossible to perform highly accurate measurements.

That is, as shown in FIG. 4, when a constant current is passed through a conductor, the temperature of the conductor increases as the current-carrying time increases, and an error occurs in the output of the current transformer.

Therefore, there has been a strong desire to develop a highly accurate gas-insulated current transformer that takes into account the effects of temperature changes in the vicinity of the optical magnetic field sensor.

(Problems to be Solved by the Invention) As mentioned above, in a conventional gas-insulated current transformer, when current flows through the conductor, the temperature of the conductor rises, and accordingly, the temperature of the conductor rises. The optical parameters of the optical element such as the Faraday element became non-uniform, the degree of polarization of the light transmitted through the Faraday element changed, and the output error of the current transformer increased, making it impossible to perform highly accurate measurements.

Therefore, the present invention was proposed to solve the problems of the prior art as described above, and its purpose is to prevent the influence of heat generated inside the conductor from reaching the vicinity of the optical magnetic field sensor. An object of the present invention is to provide a gas-insulated current transformer that greatly improves the measurement accuracy of the current transformer.

[Structure of the Invention] (Means for Solving the Problems) In order to achieve the above object, the gas insulated current transformer of the present invention includes a cooling fin provided at one end inside the conductor penetrating the shield case. A heat transfer element made of a heat pipe or the like is installed.

(Function) The gas insulated current transformer of the present invention having the above-described configuration has the following effects when current flows through the conductor and the temperature of the conductor portion changes:
A Faraday element that constitutes a magneto-optical field sensor uses a heat transfer element placed inside the conductor to dissipate the heat to the outside of the conductor so that the heat does not affect the magneto-optic field sensor placed around the conductor. The optical parameters of the optical elements such as the above do not change.

(Example) Hereinafter, an example of the present invention will be specifically described based on FIG. Note that the same members as those of the conventional type shown in FIG. 3 are given the same reference numerals, and explanations thereof will be omitted.

Configuration of this embodiment * In FIG. 1, a heat transfer element 51 made of a heat pipe or the like is disposed inside a conductor 22V so as to penetrate through connection parts 22a and 22b formed at both ends of the conductor 22V. A cooling fin 52 is attached to one end of the heat transfer element 51, and the cooling fin 52 is arranged in an adjacent conductor 60 of a gas-insulated switchgear connected to both sides of the conductor 22V. .

On the other hand, the adjacent conductor 60 transfers the heat transferred by the heat transfer element 51 to the location where the cooling fins 52 are disposed.
A hole 61 is formed for dissipating to the outside.

Effect of this embodiment* In the gas insulated current transformer of this embodiment having the above-described configuration, even if current flows through the conductor 22v and the temperature of the conductor portion rises, the heat is dissipated inside the conductor 22v. The provided heat transfer element 51 radiates into an adjacent conductor 60 which is connected to conductor 22V. Further, the heat released from the conductor 22V to the adjacent conductor 60 is roughly transferred to the heat transfer element 5.
The heat is dissipated to the outside of the adjacent conductor 60 by the cooling fins 52 provided at the end of the conductor 1 and the holes 61 formed in the adjacent conductor.

In this way, even if current flows through the conductors 22LJ to 22w and the temperature of the conductor portion changes, the heat is dissipated to the outside of the conductors 22u to 22W by the heat transfer element 51, so the surroundings of the conductors 22u to 22W Optical magnetic field sensor 23 arranged in
Temperature changes in the vicinity can be minimized. As a result, the optical parameters of the optical elements such as the Faraday element that make up the optical magnetic field sensor can be made uniform, and the degree of polarization of the light transmitted through the Faraday element can also be maintained constant, thereby preventing output errors from occurring in the current transformer. It can be prevented.

[Effects of the Invention] As explained above, according to the present invention, by the simple means of arranging a heat transfer element inside the conductor, the influence of heat generated inside the conductor can be reduced to the vicinity of the optical magnetic field sensor. Therefore, it is possible to provide a gas-insulated current transformer in which the measurement accuracy of the current transformer is greatly improved.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an embodiment of a gas insulated current transformer according to the present invention, and FIGS. Front view and side sectional view shown,
Figure 3 (A>, (B)) is a longitudinal cross-sectional view and a side cross-sectional view showing a conventional gas-insulated current transformer using an optical magnetic field sensor, and Figure 4 is a gas-insulated current transformer using a conventional optical magnetic field sensor. 1 is a diagram showing an example of output measurement by a device. 1... Tank, 2u~2W... Conductor, 3... Insulating spacer, 4... Current transformer core, 5... Support plate, 6...
...Insulation shield, 7...Sealed terminal, 21...Tank, 22U~22W...Conductor, 22a, 22b...
Connection part, 23... Optical magnetic field sensor, 24... First entrance/exit surface, 25... Support stand. 26... Magnetic shield case, 26a... Case,
26b...Lid, 26C...Insulation ring, 27...
- Hole, 28... Insulating cylinder, 29... Support container, 30.
... Hole, 31... Support member, 32... Light emitting/receiving section, 3
3... Sealed terminal, 34... Lid, 35-41...
O-ring, 42.43...Optical fiber, 44...
- Detection device, 51... Heat transfer element, 52... Cooling fin, 60... Conductor, 61... Hole.

Claims (4)

[Claims] (1) A shield case supported by an insulator is installed in the tank of a gas-insulated electrical device such as a circuit breaker, a conductor is fixed so as to pass through the shield case, and both ends of the conductor are fixed. A gas insulated current transformer is provided with a connecting portion to be connected to a conductor of a gas insulated electric device adjacent to the gas insulated current transformer, and an optical magnetic field sensor is arranged around the conductor located within the shield case. A gas insulated current transformer characterized by having a heat transfer element arranged inside the conductor. (2) The gas insulated current transformer according to claim 1, wherein the heat transfer element has a cooling fin provided at one end thereof. (3) A cooling fin is disposed within the conductor of the gas-insulated electrical device, and the conductor has a hole at the location where the cooling fin is disposed for dissipating heat transferred by the heat transfer element to the outside of the conductor. 3. A gas insulated current transformer according to claim 2, which is formed of a gas insulated current transformer. (4) The gas insulated current transformer according to claim 1 or 2, wherein the heat transfer element is a heat pipe.