JPH0368112A - Temperature monitoring device for power transmission and distribution system - Google Patents

Abstract

PURPOSE:To make it possible to easily monitor the temperature of each part of a power transmission and distribution system using an optical fiber by a method wherein a back scattered light is measured through the intermediary of the optical fiber which passes through each transformer successively. CONSTITUTION:An optical fiber 5 is airtightly passed through the pipe penetrating each pole-mounted transformer 4 of a power transmission and distribution line 2, and one end of the fiber 5 is connected to the back scattered light measuring device 6 such as a substrate (1) and the like. When an optical pulse is emitted from said device 6, a back scattered light is generated from the optical fiber 5 of the temperature raised transformer 4, this light is detected by the device 6, and the position of the transformer 4 is determined from the time difference between the time when the optical pulse is emitted and the time when the scattered light is received. As a result, the temperature of each part of the power transmission and distribution system can be monitored easily and accurately by the optical fiber.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a temperature monitoring device for a power transmission and distribution system, and more particularly to a device for collectively monitoring the temperature of a large number of transformers installed in a power transmission and distribution system at a remote location. (Prior art) A large number of transformers are used in power transmission and distribution systems, and it is important to monitor the temperature of each transformer in order to monitor the temperature of the power transmission and distribution system. The flow of water generates heat, so oil or gas is used as a cooling medium for cooling, but the temperature may rise excessively due to overload operation, short circuits, etc.To detect this excessive temperature rise. Conventionally, a temperature detection device made of bimetal or the like is installed in each transformer.

[Problem to be solved by the invention]

However, in power transmission and distribution systems, a large number of transformers are installed over a wide area, so if each transformer is equipped with a temperature detection device such as a bimetal, the means of transmitting temperature information from them to the monitoring location must be considered separately. However, there is a problem in that the configuration is complicated and it is difficult in practice to monitor the temperature of the power transmission and distribution system. This invention makes it possible to easily remotely monitor the temperature of each part of a power distribution system over a wide range by simply installing a single optical fiber.
The purpose is to provide a temperature monitoring device for power transmission and distribution systems.

[Means to solve the problem]

In order to achieve the above object, a temperature monitoring device for a power transmission and distribution system according to the present invention includes an optical fiber for temperature sensing laid along an electric line so as to be passed through each transformer in turn, The optical fiber is characterized by being equipped with a backscattered light measuring device connected to one end of the optical fiber to measure backscattered light from the optical fiber.

[Function 1] Optical fibers for temperature sensing are laid along the line so that they are passed through each transformer in turn. Generally, when a part of an optical fiber is heated, the amount of scattered light in the heated part increases. Therefore, pulsed light is input from one end of an optical fiber, and the backscattered light returning to the other end is observed.The temperature is measured based on the intensity of the backscattered light, and the backscattered light returns from the input of the pulsed light. The location where the temperature has increased can be measured based on the time it takes for the temperature to rise. Therefore, by connecting a backscattered light measuring device to one end of the optical fiber laid along the electric line and measuring the backscattered light of the optical fiber, we can measure the backscattered light of the optical fiber along the electric line. It becomes possible to measure the temperature at each part. In particular, since this optical fiber is laid so as to pass sequentially inside a large number of transformers, it is possible to monitor the temperature in each of those transformers. The backscattered light measurement device only needs to be installed at one end of the optical fiber, and from the location where this device is installed, it is possible to monitor the temperature of the power line, especially the temperature of each of a large number of transformers. . [Embodiment] Next, an embodiment of the present invention will be described with reference to the drawings. The embodiment shown in FIG. 1 shows an embodiment in which the present invention is applied to a power transmission and distribution system having an overhead power line. In FIG. 1, one end of a power transmission and distribution line 2 suspended in the air by a utility pole 3 is connected to a substation 1, and a pole transformer 4 is provided on the utility pole 3. Optical fibers 5 for temperature sensing are laid along the power transmission and distribution lines 2 so as to be passed through each pole transformer 4 one after another. In this embodiment, one end of the optical fiber 5 is guided to the substation 1 and connected to a backscattered light measuring device 6 installed there. As the optical fiber 5 for temperature sensing, a multi-mode or single-mode silica-based optical fiber can be used, and its coating material can be PE, PVC, PVC, etc.
Synthetic resins such as P and TFE, other engineering plastics, etc. can be used. In order to pass the optical fiber 5 into each transformer 4, each transformer 4 preferably has an insulating vibe 7 hermetically fixed therein, as shown in FIGS. 2A and 2B, for example. By providing the vibrator 7 in the transformer 4 from the beginning in this way, the optical fiber 5 can be installed by passing the optical fiber 5 through the vibrator 7 after installing it on the utility pole 3.
can be easily placed inside the transformer 4. The transformer 4 shown in FIG. 2A and B consists of a tank 41 containing windings and an iron core filled with oil, and a cover 42 with high-pressure measuring terminals, low-voltage side terminals 43, etc. above the insulator. It is set in. Both ends of the vibrator 7 disposed within the tank 41 are fixed to a cover 42 to form optical fiber insertion ports 8. It is important that the vibrator 7 is fixed to the cover 42 in an airtight manner, and for this reason, for example, a structure as shown in FIG. 3 is adopted. A hollow flanged bolt 81 is inserted into a hole in the cover 42, and a nut 83 is tightened to the upper end of the bolt 81, thereby fixing the bolt 81 to the cover 42. A cylindrical groove 82 is provided at the lower end of this bolt 81, and one end of the vibrator 7 is inserted into this groove 82. Then, the flanged nut 84 is screwed onto the lower end of the bolt 81, and the pin 85, which has a cylindrical shape as a whole and a wedge-shaped cross section, is inserted into the groove 82.
is pressed against the inner wall of the groove 82 to fix the vibrator 7 and provide airtightness. The vibrator 7 can be made of fluororesin, polyamide resin, polyimide resin, polyimide amide resin, etc., but in this embodiment, it is made of extruded FEP with an inner diameter of 0°8 mm and an outer diameter of 2.5 mm. A tube made of heat-resistant polyimide resin was used. After the transformer 4 having such a vibrator 7 is installed on the utility pole 3, in this example, a graded index type optical fiber with an outer diameter of 125 μm, a core diameter of 50 gm, and a relative refractive index difference of 1°0% is coated with silicone. Optical fiber 5 for temperature sensing is coated with a material having an outer diameter of 400 μm.
The optical fiber 5 was inserted into the above-mentioned pipe 7 through one of the insertion ports 8 by a so-called air blow method using gas pressure. 0TDR (
Optical Tinge Domain Refl.
ectometry) method, R-OTDR (Ran+an
0Ptical Time Domain Refl.
ectometry) method, OFDR(0ptica
Frequency DomainRef le
However, in this embodiment, the backscattered light measuring device 6 is a Raman scattered light detection type 0TDR device (R
-OTDR device) is used. In the case of an embodiment with such a configuration, the temperature of each of the pole transformers 4 installed every 20 m can be measured at the substation 1, and temperature abnormalities throughout the power transmission and distribution system, including abnormalities in transformer equipment, can be measured. could be monitored all at once by the backscattered light measuring device 6 at the substation 1. Note that this is done in order to increase the distance of the temperature sensing optical fiber 5 disposed in each transformer 4 in relation to the distance resolution of the backscattered light measuring device 6 used. The vibrator 7 can also be arranged to circulate within the tank 41. In addition, in the above embodiment, the temperature of a transformer installed on an overhead power line is detected, but temperature sensing can also be used for a transformer installed on an underground power line or a transformer installed at a substation, etc. By passing an optical fiber through it, its temperature can be detected. Furthermore, it goes without saying that the present invention can be applied not only to the oil-filled transformer as in the above-mentioned embodiments, but also to other types of transformers, such as gas-filled transformers.

【Effect of the invention】

According to the temperature monitoring device for a power transmission and distribution system of the present invention, the temperature at each part of a long electric line, especially the temperature at each of a large number of transformers, can be measured by installing a single temperature sensing optical fiber and connecting it to one end. By simply connecting a backscattered light measuring device, it is possible to easily monitor the temperature at a remote location, measure the temperature, and issue a temperature alarm. Therefore, it is also possible to omit maintenance and inspection work for the transformer equipment.

[Brief explanation of drawings]

Fig. 1 is a schematic diagram of an embodiment of the present invention, Fig. 2 A and B show a desirable specific example of the transformer, in which Fig. A is a plan view, Fig. B is a front view, and Fig. 3 is an optical FIG. 3 is an enlarged cross-sectional view of the vicinity of the fiber insertion port. 1... Substation, 2... Power transmission and distribution line, 3... Utility pole, 4
...Pole transformer, 41...Tank, 42...Cover, 43...Terminal, 5...Optical fiber for temperature sensing, 6...Backscattered light measuring device, 7...Pipe , 8... Optical fiber insertion port, 81... Hollow bolt with flange, 82... Groove, 83... Nut, 84... Nut with flange, 85... Pin.

Claims (1)

[Claims] (1) An optical fiber for temperature sensing is laid along the electric line so as to be passed through the inside of each transformer sequentially, and backscattered light from the optical fiber is connected to one end of the optical fiber and measured. A temperature monitoring device for a power transmission and distribution system, comprising a backscattered light measuring device.