JPS60263870A - Detecting device for accident point - Google Patents

Abstract

PURPOSE:To detect a ground fault accident point instantaneously by providing a current transformer installed at plural spots, both a light emitting and a photodetecting element, optical fiber, exclusive OR circuit, and a section identification code output circuit. CONSTITUTION:Current transformers 20 are installed on an overhead earth-wire; and a detection part 41 using a light emitting diode with wavelength lambda1 is connected to transformers 20 at both ends and a detection part 41 using a light emitting side with wavelength lambda2 is connected to other transformers 20. Light beams from detection parts 41 and 42 are entered into optical fibers 60 and multiplexed, and the light is wavelength-demultiplexed by a long-wavelength transmission filter 70 and photodetected by corresponding photodetecting elements 81 and 82. In this case, signals from the elements 81 and 82 are inputted to the exclusive OR circuit 91 and the section identification code output circuit 92 is operated with the exclusive-OR output; and the signal is converted by an electro- optic converting circuit 93 into a light signal, which is transmitted to a remote position through an optical fiber 94, thereby displaying an accident section on an accident point display device 96.

Description

[Detailed Description of the Invention] [Cost and Purpose of the Invention] Mitsuaki Ki (, Eng.), relates to fault point detection devices, particularly fault point detection devices suitable for detecting ground fault points of electric wires and cables '11 This is something that will open up the world to you.

Overhead power transmission lines or underground power transmission lines are essential equipment for power transmission operations in each electric power company, and an accident involving this equipment would have an extremely serious impact on today's highly electrified society. It is inevitable that this will lead to the paralysis of social functions in all areas.

For this reason, various measures are being taken to prevent accidents on these power transmission lines, but at the same time, in the unlikely event that an accident occurs,
In the event of an accident, it is extremely important to quickly locate the point of the accident and minimize the spread of the accident. In particular, the electrical insulation of power transmission lines is damaged! ? A ground fault accident is a fatal accident that cannot be repeated if left untreated.
It is extremely important to know immediately where this accident occurred. However, there has been no effective means for this in the past.

1. Ground fault indicators have been commercialized for overhead power transmission lines, but maintenance personnel must go directly to inspect the display and check the status of the indicator, which immediately identifies the fault point. 1゜Also, there is no way to quickly find out the ground fault point for underground power transmission lines.For example, fault point detection methods such as the Murray loop method and pulse radar method are However, it required a great deal of time and effort, and it was nearly impossible to immediately identify the accident point.

The present invention has been made in view of the above, and its object is to provide a fault point detection device that can instantly detect a ground fault point.

[Summary of the Invention] The present invention is characterized by: a current transformer installed at multiple points on the ground wire of a power transmission line; a light emitting element connected to each current lance for controlling rectification; An optical fiber that inputs the light from each light-emitting element to the corresponding light-receiving element, and an exclusive logic circuit that manually outputs the output of the light-receiving element corresponding to a pair of adjacent points among the F-named light-receiving elements. and a section identification code output circuit which inputs the outputs of the respective exclusive logic circuits and locates the accident section.

[Example] The present invention will be described in detail below with reference to Example J shown in FIG. 3, and FIGS. 1 and 2.

Figure 1 is an explanatory diagram showing the direction of fault current flowing in the ground circuit when a ground fault occurs on a power transmission line.When dielectric breakdown occurs between the power transmission line 1 and the ground circuit 10 at point Δ, the grounding occurs. In the circuit 10, a ground fault current flows in opposite directions to the left and right across the fault point A, as shown by arrows in the figure. 11 G: i Indicates power transmission equipment (substation).

FIG. 2 is a diagram illustrating the basic structure of a fault current detection section that detects the direction of fault current using a current transformer and a light emitting element having rectifying properties. Now, considering the moment of polarity of transmission line 1, Δ
If an IX fault occurs, the ground fault will occur in the direction of the solid arrow in the diagram (
When a two-ground fault current flows, the light emitting diode 31a lights up among the light emitting diodes 3'1a and 31b, which are connected to the current transformers 20a and 20b installed in the grounding circuit 10, respectively, and are used as light emitting elements that control rectification. The light emitting diode 31b does not light up. -7j, when a ground fault occurs at point 8, a ground fault current flows in the direction of the broken line arrow in the figure, and at this time, neither of the light emitting diodes 31a and 31b lights up.

Therefore, when the polarity of the power transmission line 1 is alternating between + and - (if a ground fault occurs at point A, the light emitting diodes 31a and 31b blink alternately, and the ground fault occurs at 8 points). If a short circuit accident occurs, the light emitting diode 31
a and 31b blink at the same time.

In this case, f=, the adjacent detection units 30a.

30b, a light emitting diode 31a.

1. When 331b flashes at intersection U, a ground fault has occurred within the section. If they blink at the same time, it means that a ground fault has occurred outside the section, so the light from the light emitting diodes 31a and 31b is input into the exclusive logic circuit after photo-electrical conversion. If this is done, the accident point can be detected.
Ru. The truth table for this relationship is shown in Table 1.

Table 1 Note O: Not in the accident zone 1: In the accident zone Note that 328 and 32b in FIG. 2 are reverse voltage protection diodes.

FIG. 3 is a block diagram of one embodiment of the fault point detection device of the present invention, and shows the case where it is applied to an overhead power transmission line. Third
In the figure, the overhead ground wire 12 is connected to a current transformer (through-type C
T) 20 are installed in five locations as one phase, and the current transformers 20 at both ends each have a long wavelength (λ1) light emitting diode, and the other current transformers 20 each have a short wavelength (λ2) light emitting diode. Detectors 41 and 42 similar to those shown in FIG. 2 are connected. The light from the light emitting diodes of each detection unit 41 passes through a half mirror 51, and the light from the light emitting diodes of detections 42 other than the center of each detection unit 42 passes through a long wavelength transmission filter 52. After entering the optical fiber 60 and collecting the light, the light is separated into wavelengths by the long wavelength transmission filter 70 and received by the corresponding light receiving elements 81 and 82, respectively. On the other hand, the light emitting die J-
The light from C is directly transmitted to light receiving element 8 via optical fiber 60.
J, which receives light at 2, is a sea urchin.

The light-receiving signals from the light-receiving elements 81 and 82 are respectively amplified by amplifiers 90, and the adjacent outputs are sent to four JJI adjunctive OR circuits 91. , the section identification code output circuit 92 is operated, and the output of each section identification code output circuit 92 is converted into an optical signal by an electrical-optical signal conversion circuit 93, and transmitted to a remote location via an optical fiber 94. The light-to-electrical signal converter 95 converts it into an electrical signal, and the fault point indicator 96
Display the accident section.

By installing one set of fault point detection devices shown in Figure 3 and installing a large number of them along the power transmission line, it is possible to immediately locate the section where an accident occurs on a long-distance power transmission line at a remote point. I can do it.

As described above, according to the embodiments of the present invention, a ground fault section of a power transmission line can be instantly detected at a remote location.

In addition, in Fig. 3, five detection parts are arranged in one silk screen.
By combining a long wavelength transmission filter and a light emitting diode, each of which has a further different wavelength characteristic, a larger number of detection units can be combined into one set. Also, the third
In the figure, a half mirror 51 and a long wavelength transmission filter 52 are used to transmit transmission through one optical fiber 60 on each side. It goes without saying that the transmission may be performed using an optical fiber.

Further, although FIG. 3 shows the system applied to an overhead power transmission line, it can also be applied to an underground pull line.

However, in this case, at the connection part of the cable, a through-type C1' is installed for connecting three wires of the sheath circuit at once to detect the zero-sequence current.

[Effects of the Invention] As described above, according to the present invention, there is an effect that a ground fault point can be instantly detected.

[Brief explanation of drawings]

Figure 1 is an explanatory diagram showing the direction of fault current flowing in the ground circuit during a ground fault on a power transmission line, and Figure 2 shows the direction of fault current from current 1 to a light emitting element that has rectification properties such as a lance. Fig. 3 is a block diagram showing an embodiment of the fault point detection device of the present invention. 12: Overhead ground wire, 20: Current transformer, 41° 42: Detection section, 60: Optical fiber, 81.82: Light receiving element, 90
: Amplifier, 91: Exclusive part PP summation circuit, 92: Section identification code output circuit. 1st rhinoceros 2 mouth helmet 3 Figure 2 675

Claims (1)

[Scope of Claims] (1) Current transformers installed at multiple points on the ground wire of a power transmission line, light-emitting cables connected to each of the current lances and having rectifying properties, 1' of each optical element L] to the corresponding light receiving element.The output of the corresponding light receiving element is output from the adjacent point on the back side of each light receiving element. Exclusive inside 1
'Alli! An accident point detection device characterized by i71-. (2) The fault point detection device according to claim 1, wherein the power transmission line is an overhead power transmission line. (3) The power transmission line is an underground power transmission line, and the currents 1 to Connect 1c of the sheath circuit at point 3
711 failure point detection device according to claim 1, which is installed for all phases and is configured to detect zero-sequence current. (4) The output of the section identification code B output circuit is transformed into an optical signal and then transmitted to a remote point via an optical fiber so that the accident point can be detected centrally. Accident point detection Ff setting as described in Section 2 or 3m.