JPS60261120A - Detector for voltage and current of three-phase integral type gas insulating electrical apparatus - Google Patents

Abstract

PURPOSE:To miniaturize an apparatus, and to measure voltage and currents precisely by equally dividing the inside of a tank by grounding grids and forming a voltage detector by mounting floating electrodes around conductors at each phase and a current detector by fitting Faraday elements around them. CONSTITUTION:Main circuit conductors u, v, w at three phase are arranged at the apices of an equilateral triangle in a tank vessel 11 filled with an insulating gas, and grounding grids 12a-12c are mounted at the contents of the main circuit conductors, and fitted to the tank vessel through fittings 12'. Cylindrical floating electrodes Fu, Fv, Fw are each mounted on the outer circumferences of the main circuit conductors u, v, w and connected to transformers Tu, Tv, Tw containing auxiliary capacitors on the outside of the tank vessel 11, thus constituting a voltage detector. Likewise, Faraday elements 17 for detecting currents are disposed, and optical fiber cables 18 are connected at projecting-and-emitting- beam terminals for said elements 17. The cables 18 are connected to beam- emitting-and-receiving sections 21 for optical CTs on the outside of the tank vessel 11 through sealing sections 20.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention mainly relates to a voltage and current detection device for gas-insulated electrical equipment using SFs gas as an insulating medium, and in particular, a device for detecting voltage and current of a live part using floating gummy electrodes. The present invention relates to a voltage/current detection device for a three-phase, circular gas-insulated electric appliance, which detects voltage by dividing the voltage of a capacitor and detects current by using an optical magnetic field sensor.

[Technical background of the invention and its problems] Conventionally, as devices for detecting the voltage and current of three-phase integrated gas-insulated electrical equipment, there are a voltage detection device (hereinafter referred to as PD) and a current detection device (hereinafter referred to as CT). Each term is known individually.

The technical background and problems of conventional PD and CT will be individually explained below.

(Problems with PD) Conventionally, PDs for gas insulated electrical equipment (GIS) are:
Capacitor-type instrument transformer, ■Amplification-type instrument transformer, ■
Amplifying type capacitor type instrument transformers are used. Recently, from the perspective of reducing the size of substation sites, the size of each component of gas-insulated electrical equipment has progressed, and P
As for D, the above-mentioned ■, and also the above-mentioned ■ have come to be applied rather than the above-mentioned ■.

By the way, the biggest problem when applying an amplified capacitor type voltage transformer to multi-phase equipment such as three-phase gas-insulated electrical equipment is that the voltage detection electrodes of each phase are not affected by the conductors of other phases. The problem lies in how to faithfully detect the voltage of the conductor of the own phase without receiving any error.

Conventionally, there have been such amplification type capacitor type voltage transformers as shown in FIGS. 1 and 2. 1st
The figure shows an axial cross-section of the device, and FIG. 2 shows a cross-section of the device. , each phase voltage detection electrode 4a, 4b facing each of the conductors,
4. C (not shown) has a spherical shape, and is connected to grounded shield pipes 3a, 3b,' extending in the longitudinal direction of the conductor in order to shield the vicinity of the facing portion of each phase conductor and voltage detection electrode from other phase conductors. 3c (not shown).

However, in the above example, for example, the B-phase voltage detection electrode 4
In addition to the capacitance Cbb between the conductors 2b of the own phase, b is the capacitance ff1cba with the conductor 2a of the A phase and C not shown.
It is affected by the capacitance Cbc between the phase conductor 2C. Therefore, in order to avoid the influence from other phases, Cbb>>C
In order to realize ba, Cbb>>CbC, it is necessary to increase the distance from the end of the shielded pipe 3b in Fig. 1 to the voltage detection electrode 4b, which increases the overall dimensions of the device, so gas insulation is required. This had the drawback of going against the intention of downsizing electrical equipment.

(Issues regarding CT) On the other hand, in recent years, with the increase in electricity demand in Japan, the 500KV class that has already been realized is expected to appear in the future.
The development of power transmission systems has progressed to 1,000KV class, and the transmission current has increased from 8KA to 12KA, and the short-time fault current has increased from 50KA.
It continues to grow at 63KA. However, under these circumstances, in substations and inter-stations, the influence of electromagnetic interference on the electric wires connecting current transformers and relay rooms has become significant, which has become a problem. Therefore, recently, optical fiber cables, which are completely unaffected by electrical noise, have attracted attention and their use is being considered in place of electric wire cables.

In addition, conventional wire-wound CTs have good measurement accuracy because they can integrate the magnetic path caused by conductor current over the entire circumference, but they require considerable time and effort to assemble the windings. It has drawbacks such as very high manufacturing cost, heavy weight, and large size. Therefore, in CT, instead of the wire-wound type, inexpensive, low weight, and compact magneto-optical elements that utilize the Faraday effect have recently attracted attention, and these elements can be placed around the bus conductor to measure current. A method of promoting the miniaturization of CT in gas-insulated electrical equipment and the digitalization of monitoring systems at electrical stations is being studied.

(Overall problems) In this way, in three-phase all-in-one gas insulated electrical equipment,
For both PD and CT, there is a need to improve reliability by downsizing the equipment and reducing the influence of adjacent phases.
Furthermore, there were the following problems.

In other words, each conventional detection device is installed as a separate component, and as mentioned above, each dedicated installation requires space, but in addition, a separate connection bus bar is required to connect them. It was necessary to set one up, and we also had to prepare a space for it. For example, FIG. 7 shows a gas insulated switchgear equipped with a main bus Bus i't gas breaker GOBS disconnector O8. Not only are the PDs themselves large, but the connecting bus BUS2 between them occupies a considerable amount of space.

OBJECT OF THE INVENTION The present invention was proposed in order to solve the problems of the prior art as described above, and its purpose is to reduce the current and voltage of the conductors of each phase without being influenced by other phases. An object of the present invention is to provide a voltage and current detection device for a three-phase integrated gas-insulated electric device that can accurately detect the voltage and can greatly contribute to downsizing of the gas-insulated electric device.

[Summary of the Invention 1 The voltage and current detection device for a three-phase, circular gas-insulated electrical equipment according to the present invention divides the inside of a tank container equally into three or more grounding grids in the radial direction, and connects these grids to each phase. The main circuit conductors of each phase are arranged in the center of the adjacent grids, and floating electrodes supported insulated from the tank container are arranged around the main circuit conductors of each phase. A PD is constructed by dividing the potential of a circuit conductor using a capacitor, and the voltage of each phase is detected without being affected by electromagnetic induction from other phases.

In addition, a Faraday element for CT is placed so as to surround the conductor of each phase at the location where the floating electrode of the conductor of each phase is installed, and this Faraday element is led out to the outside of the tank container via an optical fiber cable. By configuring an optical CT, it is significantly smaller than a conventional wire-wound CT, and it is also possible to integrate around the circumference of a conductor, making it possible to measure current with high accuracy. .

[Embodiments of the Invention] An embodiment of the voltage/current detection device for a three-phase/talk type gas insulated electric appliance according to the present invention as described above will be specifically described with reference to FIGS. 3 to 6.

First, a single line diagram of a voltage/current detection device for a three-phase, linear gas-insulated electric appliance according to the present invention is shown in FIG.

In carrying out the construction, the configuration of the main circuit conductor can be an equilateral triangular arrangement or an isosceles triangular arrangement.Here, we will discuss an example in which the present invention is applied to a three-phase collective busbar in an equilateral triangular arrangement. , will be explained based on FIGS. 4 and 5.

Tank container 11 filled with insulating gas such as SF6 gas
Inside, three-phase main circuit conductors U, V, and W are arranged on the vertices of an equilateral triangle. Main circuit conductor U.

At the center of each of the V and W is a grounding grid 12 that is centered on the axis of the tank container 11 and extends linearly in the radial direction.
a to 12c are provided and attached to the tank container 11 via support fittings 12-, and the tank container interior 11 is divided into three equal parts in the radial direction by these three grounding grids 12a to 12c. In addition, the main circuit conductors U, V
, W are provided with cylindrical 70-teating electrodes Fu, Fv, and Fw coaxially with the outer periphery of each of these 70
0-ting electrodes are connected to respective ground grids 12a-12c.
Each insulator 13 is attached to two adjacent grounding grids.
has been fixed through. In addition, each dielectric tank container 1
1. Main circuit conductors U, V, W, grounding grids 12a to 12
The relative positional relationship between c and the floating electrodes Fu to FW is constant. Each floating electrode Fu~FW
are each 70-ring electrode F of tank container 11, respectively.
The transformation unit TLI includes a tulip-shaped contact 14 attached at a position closest to LJ to Fw, and an auxiliary capacitor disposed outside the tank vessel 11 via a conductor 116 passing through an insulated sealed terminal 15.

Connected to Tv and Tw. Further, the floating electrodes Fu to Fw are arranged at the center of the grounding grids 12a to 12c in the axial direction, and the length of the grounding grid 1 is approximately twice or more the length IL2 of the 70-ring electrode. There is.

On the other hand, on the outer circumference of the main circuit conductors U to W of each phase at the same location as the floating electrode Fu-Fwii device, a Faraday element 17 for current detection is arranged so as to surround the main circuit conductor. An optical fiber cable 18 is connected to the input/output terminal of the element 17. Main circuit conductor U~W
An insulating cylinder 19 is provided on the extension of the insulator 13 on the ground grid side between the floating electrode F LJ -F W, and an optical fiber cable is passed through the hollow hole 19a of the insulating cylinder 19. 18 are led out to the outer space of the floating electrodes Fu to FW. Furthermore, an optical fiber sealed part 20 is provided in the tank container 11 in line with the insulated sealed terminal 15 for PD, and the optical fiber cable 18 is connected to the outside of the tank container 11 via the sealed part 20 to the same transformation part Tu-. It is connected to a light emitting/receiving section (output section) 21 for optical CT, which is arranged in parallel with Tw.

In addition, both ends of the main circuit conductors U to W of each phase in the axial direction have a detachable structure in which contacts 22 are formed outside both ends of the grounding grids 12a to 12c. The tank container 11 also has seven tank parts 11a on both sides,
It is said that it can be attached to and detached from seven tank parts of other tanks (not shown) at the same location.

The operation of this embodiment having the above configuration is as follows.

◆ That is, as a PD, the floating electrode Fu-
The potential divided at Fw is led out to the transformation unit Tu-TW outside the tank container 11 through the tulip-shaped contact 14 and the conductor 16, where the detected voltage becomes an electrical output and is isolated from the gas-insulated electrical equipment. He is guided by a guard M.

Here, the internal space of the tank container 11 is grounded by a grounding grid 12a.
Since it is electrically divided into three parts at ~12c, each phase is electrically independent, and the influence of electrostatic induction from other phases is effectively eliminated.

In this case, the floating electrodes Fu to Fw are provided in a coaxial cylindrical shape around the main circuit conductor U-W of each phase, and the distance relationship between the floating electrode F LJ -F w and the ground potential (tank container and ground grid) Since the capacitances between the floating electrodes Fu and FW surrounding the main circuit conductor U-W of each phase are made equal, respectively, the capacitances C+ u, C+ V,
C+W, and the respective capacitances IC2u, C2V, C between each 70-ring electrode Fu-FW and the tank container 11
2W are respectively C+ LJ=C+ V=C+ W, 0
2 U=C2V=C2W holds true. Therefore, 7 of each phase
The potentials of the 0-ting electrodes F u - F W can be easily shared at the same potential, and there is almost no need for capacitance adjustment to control the divided potential.

In addition, the floating electrodes Fu to Fw are arranged at the center of the grounding grids 12a to 12c in the axial direction, and the length of the grounding grid is approximately twice or more the length fL2 of the floating electrode. , the floating electrode Fu-FW is sufficiently electrically independent even at its ends, and there is no fear of being influenced by other phases here.

In addition, as a CT, the Faraday element 17 that measures the current of the main circuit conductors U-W is arranged on the outer circumference of the main circuit conductors U-W so as to surround them, so it is possible to integrate the circuit around the conductor circumference. Therefore, it can be expected to have the same measurement accuracy as a conventional wire-wound CT. Moreover, since it is possible to configure a very small size,
The space is significantly reduced.

Furthermore, when a high voltage is applied to the optical fiber cable 18, there is a risk that dielectric breakdown will occur. -Since the FW is not drawn out to the outside, insulation reliability is further improved.

In particular, the greatest advantage of the present invention is that the 3-phase PD and 0 units are all arranged around the main circuit conductor U-W at the same location in the axial direction of the same tank container 11, so gas insulation is achieved. A significant reduction in the axial length of electrical equipment is achieved.

For example, what is shown in FIG. 8 is an example in which the present invention is applied to gas-insulated electrical equipment with a single-bus cable lead-in, but compared to the conventional type shown in FIG. Since they are all housed in the same tank BUSa, the space for each is reduced, and the extra connection bus bar BUS2 is also no longer required, significantly reducing both the length and height of the entire gas-insulated electrical equipment. ing.

Furthermore, in this embodiment, the sealed terminal 15 for PD of each phase, the optical fiber sealed part 20, the transformation part for PD, and the light emitting/receiving part (output part) 21 for optical CT are installed together. , the structure is simplified and downsized, leading to improved manufacturing efficiency.

Furthermore, in this embodiment, the tank container 11 and both ends of the main circuit conductor U-W in the axial direction are designed to be detachable, so the unit can be easily replaced without affecting other equipment, and the equipment can be tested. Another advantage is that operations such as replacement in the event of damage can be done in a very short time and in a single step.

Of course, the voltage and current detection device for a three-phase, linear gas-insulated electric device of the present invention is not limited to this, and the sealed terminal and transformation section for PL and the sealed section and light emitting/receiving section for CT are located in different locations. It is also possible to have a configuration in which they are provided in a single box, or they can be stored all at once in the same box. Furthermore, it goes without saying that sufficient effects can be obtained without necessarily having a unit configuration.

In addition, when the device of the present invention is applied to a connection bus bar in which the main circuit conductors are arranged in an isosceles triangle, the tank container 31 is divided into four equal parts by four grounding grids 32a to 32d, as shown in FIG. In Figure 5, the main circuit conductor u of each phase
-7W is provided at the center between the grids 32a and 32b, between the grids 32b and 320, and between the grids 32c and 32d, respectively, and therefore the space S between the grids 32d and 32a is a space in which no conductor is accommodated. The other configurations are exactly the same as all the embodiments, and therefore the effects are also the same.

Furthermore, in the above two embodiments, the voltage detected in PDl, : is extracted as an electrical output at the transformers Tu to Tw, but the present invention is not limited to this, and the transformer is connected to the light converter. Alternatively, the detection voltage may be extracted as optical output like a CT. Furthermore, the 70-ring electrode is not limited to a cylindrical one, but may be a plate-shaped one.

Furthermore, in CT, the position where the optical fiber cable is led out to the outside of the floating electrode can be freely selected.
For example, a case may be considered in which it is led out from the sealed terminal side.

[Effects of the Invention] As explained above, according to the present invention, the inside of the tank is equally divided by a grounding grid, and 70=teating electrodes are provided around the conductor of each phase to constitute a PD. A Faraday element is provided so as to surround the main circuit conductor at the location where the 70-ring electrode is provided on the main circuit conductor, and this is connected to an optical fiber to form a CT, thereby creating a structure that combines PD and CT. While reducing the overall size of gas-insulated electrical equipment,
Moreover, it is possible to provide a voltage and current detection device for three-phase, wire-type gas-insulated electrical equipment that can accurately measure the voltage and current of the conductor of each phase without being influenced by the signal phase.

In particular, in the present invention, since the Faraday element is directly wound around the conductor in CT, it is possible to obtain high measurement accuracy, and the number of elements to be wound can also be small, making it highly economical. Also, in the manufacturing process, the work of winding elements around conductors is easier than in conventional wire-wound CTs, and the number of parts can be significantly reduced.

[Brief explanation of drawings]

1 and 2 are an axial sectional view and a transverse sectional view, respectively, showing a conventional amplification type capacitor type instrument transformer, FIG. 3 is a single line diagram showing the device of the present invention, and FIG. 4 and fifth
The figures are an axial sectional view and a cross-sectional view, respectively, showing an embodiment of a voltage and current detection device for a three-phase, circular gas-insulated electric appliance according to the present invention, and FIG. FIG. 7 is a schematic diagram showing an example of gas-insulated electric equipment constructed using conventional PD and CT, and FIG. 8 is a cross-sectional view showing another embodiment of the PD of the device. 1 is a schematic diagram showing an embodiment of a gas insulated electrical device configured using a voltage/current detection device for a gas insulated electrical device. 11.31...Tank container, 12a to 12G, 32a
~32d...Grounding grid, 13...Insulator, 14
...Tulip-shaped contact, 15...Insulated sealed terminal, 16...Conductor wire, 17...Faraday element, 1
8... Optical fiber cable, 19... Insulating tube, 2
0... Optical fiber sealed part, 21... Light emitting/receiving part (output part), 22... Contact, U-W... Main circuit conductor,
Fu-Fw...70-ding electrode, T u -T
w... Metamorphosis part. Applicant Toshiba Corporation Agent Patent Attorney Mitsuo Kiuchi, 5, - Figure 1 Figure 2 Figure 3 Figure 41! I No. 51!1 11a Figure 6

Claims (7)

[Claims] (1) Fill the tank container with insulating gas such as SF6 gas, store the three-phase main circuit conductors all together, and divide the inside of the tank container equally in the radial direction with three or more grounding grids. , these ground grids are arranged so that the main circuit conductors of each phase are located in the center between the adjacent ground grids, and the main circuit conductors of each phase are surrounded by the ground grids insulated from the tank container. Floating electrodes supported by a grounding grid are arranged respectively, and the voltage divided by the floating electrodes is drawn out from the tank container,
A voltage detection device is configured by connecting to a transformer or an optical conversion unit, and a Faraday element for current detection is arranged so as to surround the conductor at a location where the floating electrode is provided on the main circuit conductor of each phase, An optical fiber cable is connected to the light input/output terminal of the Faraday element, and the optical fiber cable is led out to the outside of the tank container and connected to the light emitting/receiving section to constitute a photocurrent detection device. - Voltage and current detection devices for spoken gas insulated electrical equipment. (2) The three-phase bulk gas insulated electrical appliance according to claim 1, wherein the optical fiber cable is drawn out to the outside of the 70-prong electrode via an insulating tube provided between the main circuit conductor and the floating electrode. Equipment voltage and current detection device. (3) The voltage and current detection device for a three-phase, linear gas-insulated electric appliance according to claim 1, wherein the main circuit conductors are arranged in an equilateral triangle and the number of grounding grids is three. (4) A voltage/current detection device for a three-phase, linear gas-insulated electric appliance according to claim 1, wherein the main circuit conductors are arranged in an isosceles triangle arrangement and the number of grounding grids is four. (5) The three-phase system according to claim 1, wherein the insulating sealed terminal and the optical fiber sealed part for the voltage detection device are installed together or integrally on the tank container for each dielectric. Voltage and current detection device for spoken gas insulated electrical equipment. (6) A patent claim in which a transformation section or a light conversion section for a voltage detection device and a light emission/reception section for a photocurrent detection device are installed together or integrally in each phase conductor in the external space of the tank container. A voltage and current detection device for a three-phase, linear gas-insulated electric appliance according to item 1. (7) Claim 1, wherein the tank container is provided with connection flanges at both ends in the axial direction, and the main circuit conductor of each phase has contacts formed at both ends in the axial direction. The voltage and current detection device for the three-phase, linear gas-insulated electrical equipment described above.