JP2685906B2 - Transmission line accident section locator - Google Patents

Description

Description: [Industrial field of use] The present invention relates to a faulty section locating device for a transmission line.

[Prior Art] The present applicant first installed an optical fiber in parallel with a power transmission line to detect a faulty section of the power transmission line, and provided a fault current direction determination device at appropriate intervals along the power transmission line. , A transmission loss imparting means for imparting a transmission loss by applying a lateral pressure of a natural period to the optical fiber according to the determination output issued by the device, and the optical fiber terminal has different periods transmitted through the optical fiber. We have proposed a faulty section locator for transmission lines that analyzes the loss frequency of the transmission line and locates the faulty section (Japanese Patent Application No.
63-240927).

[Problem to be Solved by the Invention] However, in such a conventional fault section locating device for a transmission line, mechanical lateral pressure is repeatedly applied to the optical fiber by the transmission loss giving means, so that the life of the optical fiber is shortened, There is a problem that reliability cannot be maintained for a long period of time.

An object of the present invention is to provide a faulty section locating device for a transmission line that can locate a faulty section without reducing the life of the optical fiber.

[Means for Solving the Problems] To show the configuration of the present invention for achieving the above object,
It is as follows.

The accident section locating device for a power transmission line according to claim (1) is an accident in which an optical fiber arranged in parallel with the power transmission line is installed at an appropriate interval along the power transmission line and flows into an overhead ground line of the power transmission line. A plurality of faults that determine the direction of the fault current flow according to the polarity of the first half cycle of the current and send the fault current flow direction and the determination position, which are the determination results, to the optical fiber as unique optical signals. A current direction determination device, and an inherent frequency whose frequency magnitude sequentially changes corresponding to a determination position along the line direction of the power transmission line, which is connected to the detection end of the optical fiber and receives the specific optical signal. An optical / electrical converter for converting into an electric signal of
A frequency analyzer connected to the output terminal of the electric converter to analyze the frequency of the electric signal and change the display manner in frequency order and in accordance with the direction of the fault current flow. is there.

The fault current direction determination device according to claim (2) determines the direction of the fault current flow according to the polarity of the first half cycle of the fault current, and the fault current flows in one direction of the overhead ground wire. A fault current direction determining device main body that outputs 1 when the fault current flows through the overhead ground wire in a direction opposite to the one direction, and outputs 2 when the fault current flows; A frequency that outputs a frequency signal having a natural frequency corresponding to the output position when any one of them is output and indicating a determination position as a frequency signal whose frequency magnitude sequentially changes corresponding to the determination position along the line direction of the power transmission line. It is characterized by having a signal sending unit and an electric / optical conversion unit for converting a frequency signal of the natural frequency into a unique optical signal. [Operation] In the present invention as described above, when an accident such as a ground fault accident or a short-circuit accident occurs in a power transmission line, a fault current based on the accident flows from the transmission line to the overhead ground line, and this fault current is generated before the accident occurs. If the power source is on both sides of the transmission line, the fault current flows from both sides of the transmission line into the overhead ground line.Therefore, a fault current of opposite phase flows at the fault point. That is, the first half cycle flows on one side of the overhead ground wire with one polarity, and the first half cycle flows on the other side of the overhead ground wire with the other polarity. In some cases, the accident current may flow to the overhead ground wire only from the side with the power source at the boundary of the accident point, and not to the overhead ground wire on the opposite side of the accident point. It occurred at the same time if the polarity of the first half cycle of the current was detected This was done focusing on the fact that fault currents can be detected.

In claim (1), an optical fiber is arranged in parallel in the transmission line,
In addition, the fault current direction determining devices are installed at appropriate intervals along the transmission line, and the fault current direction determining devices detect the first half cycle of the fault current flowing through the overhead ground wire, and the polarity of the fault current causes the fault current flow. Since the respective directions are determined, the fault current generated at the same time can be detected and the direction of the fault current flow at each determination position can be known. Since a unique optical signal indicating the direction of the fault current as a result of this judgment and its judgment position is formed and sent to each optical fiber, the data at all judgment positions are collected in one place by the optical fiber. be able to. At this time, the determination result can be transmitted to the optical fiber without repeatedly applying mechanical lateral pressure. At the detection end of the optical fiber, the unique optical signal sent from this optical fiber is changed by the optical-electrical converter to a unique frequency whose frequency magnitude changes in sequence according to the judgment position along the line direction of the transmission line. Convert it to an electrical signal,
The frequency of this electric signal is analyzed by a frequency analyzer, and the display method is changed according to the direction of the flow of the fault current and displayed. Therefore, the position of the fault can be known from the state of the display. .

In claim (2), since the fault current direction determination device outputs one of two types of frequency signals indicating the direction of the fault current, the fault section can be determined regardless of whether the power transmission line is a double-sided power source or a single-sided power source. Like

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 shows a first embodiment of the present invention.
As illustrated, the overhead ground wire 2 of the transmission line 1 and the transmission line 3 is supported by the tower ₄₁ to ₄ at appropriate intervals in the longitudinal direction. Each tower 4 In _{1-4 4} position, current transformer to ground wire 2 in order to detect the first polarity of half cycle of fault current (hereinafter, referred to as CT) 5 ₁ to 5 ₄ are provided. The output terminals of the CTs 5 _{1 to} 5 ₄ are connected to the fault current direction determination devices 6 _{1 to} 6 ₄ , respectively. In addition, an optical fiber 7 is installed in parallel in the power transmission line 1 by, for example, being built in the overhead ground wire 2.
Each of the fault current direction determination devices 6 _{1 to} 6 ₄ is designed to output a unique optical signal indicating the determination result of the direction of the fault current flow determined by the polarity of the first half cycle of the fault current and its determination position. There is. Specific optical signals output from the fault current direction determining device ₆₁ through _4, each fault current direction determining device ₆₁
It is adapted to be fed into the optical fiber 7 via the optical multiplexer 8 _{1-8 4} respectively provided on the optical fiber 7 so as to correspond to the 6 _4. At the terminal of the optical fiber 7, an optical-electrical conversion that converts the received unique optical signal into an electrical signal of a unique frequency whose frequency magnitude sequentially changes corresponding to the determination position along the line direction of the power transmission line 1 The container 9 is connected. For example, the unique optical signals from the fault current direction determining devices 6 _{1 to} 6 ₄ are converted by the optical / electrical converter 9 into electrical signals of natural frequencies f _{1 to} f ₄ . The electric signal from the optical / electrical converter 9 is
The signals are input to the frequency analyzer 10, the frequencies are analyzed, and the output signals are displayed in the order of the detected frequencies and the display method is changed according to the direction of the flow of the fault current as shown in FIG. It is like this. In this example, towers 3 ₂ and 3 ₃
It is shown as an example in which there is an accident point X between and.

Figure 3 is, of the fault current direction determining device ₆₁ through ₄ shows the internal structure of the fault current direction determining device ₆₁ as a representative. The fault current direction determining device ₆₁ is by the initial polarity of half cycle of fault current flowing from the power transmission line 3 at the fault point X to ground wire 2 to determine the direction of flow of the fault current, any one direction For example, the fault current direction determination device main body 11 ₁ which outputs the output 1 and outputs the output 2 in the opposite direction to the one direction, and the natural frequency f which corresponds only to the output 1 when the output 1 is output and indicates the determination position. _A frequency signal transmission unit 12 _{1 including} an oscillator that outputs a frequency signal of ₁ and an electrical / optical conversion unit 13 ₁ that converts the frequency signal of a natural frequency f ₁ into a unique optical signal and outputs the optical signal when the frequency signal of the natural frequency f ₁ is input. It is configured. Other fault current direction determining device 6 _{2-6 4} also, although not shown the internal structure includes a fault current direction determination apparatus 11 _{2-11 4} Similarly, natural frequency and operating only when the output 1 is issued Equipped with frequency signal transmitters 12 _{2 to} 12 ₄ that output f _{2 to} f ₄ and electro-optical converters 13 _{2 to} 13 ₄ that output unique optical signals to inputs of natural frequencies f _{2 to} f _4. Is configured. Each fault current direction determination apparatus 11 ₁ to 11 ₄ in the fault current direction determining device ₆₁ through _4, the first half cycle polarity detection of the fault current (i.e., the determination direction of the flow of fault current) A pair of well-known photodiodes and phototransistors is used as a pair of photocouplers CT5 _1-
5 ₄ by connecting the photodiode side in anti-parallel, respectively, and the polarity of the detected first half cycle output from the phototransistor of either photocoupler (that is, the direction of the determined fault current flow) ) Is held by each well-known latch circuit connected to the output terminals of these photocouplers, and outputs 1 when the fault current flow is in one direction, and outputs when the fault current is in the opposite direction. Two
It is designed to output. In addition, the frequency signal transmitter 12 ₁
12 _4, the natural frequency f ₁ ~ in which the magnitude of the frequency is changed sequentially in accordance with the determination position by the fault current direction determining device ₆₁ through ₄ along the line direction of the transmission line 1 when the output 1 is sent
It is designed to output a frequency signal of f ₄ .

FIG. 4 (A) (B) shows a first polarity by the fault current direction determination apparatus 11 ₁ to 11 ₄ of the output 1 and output 2 output from the relationship of the half cycle of the fault current. That is, as shown in FIG. 4 (A), if the polarity of the first half cycle of the fault current is positive, the output 1 indicating that the flow direction of the fault current is unidirectional is output. On the other hand, if the polarity of the first half cycle of the fault current is negative as shown in FIG. 4 (B), the output 2 indicating that the flow direction of the fault current is opposite to the one direction is output. put out.

Next, the operation of the faulty section locating device for the transmission line as described above will be described. As described above, an antiphase fault current flows through the overhead ground wire 2 with the fault point X as a boundary. The fault current direction determination devices main bodies 11 _{1 to} 11 ₄ of the respective fault current direction determination devices 6 _{1 to} 6 ₄ that determine the direction of the flow of the fault current have a polarity of (+) in the first half cycle of the fault current. In case of, output 1 indicating that the fault current is flowing in one direction,
When the polarity of the first half cycle of the fault current is (-), the output 2 indicating that the fault current is flowing in the opposite direction to the one direction is output. This makes it possible to know whether the fault current has flown in either direction of the overhead ground wire 2.

In this case, as shown in FIG. 5, when there are power sources 14 at both ends of the power transmission line 3, the fault current starts from the fault point X in both directions of the overhead ground wire 2, that is, the direction of each power source 14 as shown by an arrow. Flow in the opposite phase.

On the other hand, as shown in FIG. 6, when the power supply 14 is provided only on one side of the power transmission line 3, the fault current starts from the fault point X and is in the direction in which the power source 14 exists as shown by the arrow. It flows to the overhead ground line 2 only. In this way, in the case of a single power source, the fault current does not flow to the load 15 side opposite to the power source 14 side (right side in FIG. 6) from the fault point X, because the ground point of the overhead ground wire 2 on the load 15 side is From the earth to the power supply 14
This is because it is significantly longer than the earth return path from the ground point of the overhead ground wire 2 on the 14 side to the power supply 14, and the insulation resistance of the ground return path on the load 15 side is significantly larger than the insulation resistance of the ground return path on the power supply 14 side. .

Therefore, in the case of the transmission line 1 of dual power sources shown in FIG. 5, the fault current direction determination device in the section on the left side of the fault point X
6 _1, 6 ₂ of the fault current direction determination apparatus main body 11 _1, 11 ₂ Output 1 showing the direction of flow of the fault current in, only the output one of the output 2 are outputted. In addition, the fault current direction determination device main body 1 of the fault current direction determination devices 6 ₃ and 6 ₄ in the section on the right side of the fault point X
1 ₃ and 11 ₄ show output 1 and output 2 indicating the direction of fault current flow
Of these, only output 2 is output.

On the other hand, in the case of the single power transmission line 1 shown in FIG.
Fault current direction determination device 6 ₁ , 6 ₂ on the left side of the fault point X
The output 1 of the outputs 1 and 2 indicating the direction of the flow of the fault current is output from the fault current direction determination device main bodies 11 ₁ and 11 ₂ . In addition, in the fault current direction determining devices main body 11 ₃ and 11 ₄ of the fault current direction determining devices 6 ₃ and 6 ₄ on the right side of the fault point X, one of output 1 and output 2 indicating the direction of the fault current flow. Is not output.

 Table 1 shows this relationship.

In Table 1, in the case of dual power supply and single power supply, the upper row shows output 1 when the first half cycle of the fault current is (+).
Is output, and output 2 is output in the case of (-), while the lower stage outputs output 2 when the first half cycle of the fault current is (+), and (-) In this case, each output when the output 1 is output is shown.

In the case of dual power sources, if the accident point X is in Sakai and the accident current flows through the overhead ground wire 2 as shown in FIG.
Fault current direction determination device at each detection location via 5 _{1 to} 5 ₄ 6 ₁ to
It is input to the main unit 11 _{1 to} 11 ₄ of the fault current direction determination device of 6 ₄ .

In FIG. 5, the accident current direction determination device on the left side of the accident point X
6 _1, 6, the fault current direction determination apparatus main body 11 _1, 11 ₂ in the _2, CT5 _1, 5 ₂ detects and the first polarity of half cycle of fault current provided via the flow direction of the fault current from the polarity Is output respectively. These outputs 1
Is input to the corresponding frequency signal transmitters 12 ₁ and 12 ₂ to indicate the determination positions (installation positions) of the fault current direction determination devices 6 ₁ and 6 ₂ and the natural frequencies f ₁ and f that indicate the fault current flow direction. _It is converted into a frequency signal of ₂ and input to the corresponding electric / optical converters 13 ₁ and 13 ₂ . Each of the electric / optical converters 13 ₁ and 13 ₂ has a natural frequency
When the frequency signals of f ₁ and f ₂ are input, they are converted into unique optical signals. The obtained unique optical signals are sent to the optical fiber 7 via the optical multiplexers 8 ₁ and 8 ₂ and transmitted to the detection end side. In this embodiment, these peculiar optical signals are converted into optical signals of different frequencies so that they can be easily separated individually on the detection end side.

In FIG. 5, the accident current direction determination device on the right side of the accident point X
6 _3, the fault current direction determination apparatus main body 11, not shown in the 6 _4
3, in 11 _4, and outputs CT5 _3, 5 ₄ and the accident current provided through the first to detect the polarity of half cycle only output 2 showing the flow direction of the fault current from the polarity, respectively. Since these outputs 2 are not input to the frequency signal transmitters 12 ₃ and 12 _{4 (} not shown) as described in FIG. ₃ , they are unique to the fault current direction determination devices 6 ₃ and 6 ₄ on the right side of the fault point X. No optical signal is output.

At the detection end, the optical / electrical converter 9 converts the transmitted unique optical signal into the original electrical signals of the natural frequencies f ₁ and f ₂ .
The converted electric signals of the natural frequencies f ₁ and f ₂ are input to the frequency analyzer 10 and subjected to frequency analysis to obtain the natural frequencies.
The electric signals of f ₁ and f ₂ are separated, and as shown in FIG. 2, the frequency is displayed on the horizontal axis and the signal strength is displayed on the vertical axis. By looking at this display, the frequency f ₂
And the frequency f ₃ not displayed at the desired position, in other words, between the towers 4 ₂ and 4 _{3 where the} fault current direction determining devices 6 ₂ and 6 ₃ are installed, the fault point X is It turns out that it exists.

By the way, in a fault current direction determination device using only output 1 as shown in FIG. 3, in the case of dual power supplies, as is clear from Table-1, output 1 is output at any place in both upper and lower stages. Since there is no problem, the table-
As is clear from No. 1, there is a case where output 1 is not output at all in the lower stage, and it becomes impossible to judge the accident section.

This has been solved by the second embodiment of the present invention shown in FIG. Also in this embodiment, each fault current direction determination device 6 ₁
Of 6 ₄ shows the internal structure of the fault current direction determining device ₆₁ as a representative. In the fault current direction determining device _61, the output 1, the natural frequency showing the corresponding and position determination to the output 2 showing the flow direction of the fault current of the fault current direction determination apparatus main body 11 ₁
Frequency signal transmitters 12A ₁ and 12 for generating frequency signals f ₁ and f ₁ ′
B ₁ and, combining circuit 1 combines the frequency signals from the frequency signal transmitting unit 12A _1, 12B ₁ gives the electric-optical conversion unit 13 ₁
6 ₁ is different from the device 6 ₁ shown in FIG. Other fault current direction determining device 6 _{2-6 4} also, its internal structure is not shown, similarly fault current direction determination apparatus main body 11
And _{2-11. 4,} the output shows the direction of flow of the fault current 1 operates when the output 2 is issued, they output 1, the natural frequency f ₂ ~f ₄ showing the corresponding and position determination to the output 2, f ₂ a frequency signal transmitting unit _{12A 2 ~12A 4, 12B 2 ~12B} 4 to issue an output of '~f _4', the corresponding signal among the frequency signals of the natural frequency _{f 2 ~f 4, f 2 '} ~f 4' The combining circuit units 16 _{2 to} 16 ₄ for combining and the electric / electrical units for converting the frequencies f ₂ , f ₂ ′, f ₃ , f ₃ ′ or f ₄ , f ₄ ′ of the combined signals into their own optical signals. The light conversion units 13 _{2 to} 13 ₄ are provided. Each frequency signal transmitter 12A _{1 to} 12A ₄ ,
The frequencies of 12B _{1 to} 12B ₄ are sequentially changed according to the judgment position of each fault current direction judgment device 6 _{1 to} 6 ₄ along the line direction of the transmission line 1 when the output 1 and the output 2 are transmitted. It outputs the frequency signals of natural frequencies f _{1 to} f ₄ and f ₁ ′ to f ₄ ′.

Next, the operation of the accident section locating device of the second embodiment will be described. As mentioned above, the overhead ground wire 2
A fault current flows at the fault point X. Fault current direction determination device for determining the direction of such fault current flow 6 ₁ ~
The fault current direction determining device main bodies 11 _{1 to} 11 ₄ of 6 ₄ output 1 when the polarity of the first half cycle of the fault current is (+),
Output 2 is output when the polarity of the first half cycle of the fault current is (-).

At this time, in the case of the dual power source shown in FIG.
At the boundary of the fault current direction detectors 6 ₁ , 6 ₂ on the left side in FIG.
In the fault current direction determination device main bodies 11 ₁ and 11 _{2 of FIG. 1} , both the device main bodies 11 ₁ and 11 ₂ output the output 1 indicating the flow direction of the fault current, respectively, as shown in the upper row in the case of _dual power sources in Table 1. To do. Also, the fault current direction determination device main body 11 ₃ , 1 of the fault current direction determination device 6 ₃ , 6 ₄ on the right side in FIG.
In 1 ₄ , as shown in the upper part of the case of dual power sources in Table-1, both device main bodies 11 ₃ and 11 ₄ each output output 2 indicating the flow direction of the fault current. Accident current direction determination device body 1
Each output 1 from 1 ₁ and 11 ₂ corresponds to the corresponding frequency transmitter 12
A ₁ and 12 A ₂ are converted into frequency signals of natural frequencies f ₁ and f ₂ indicating the flow direction of the fault current and the judgment position, and the electric / optical conversion unit 13
_It is converted into a unique optical signal by ₁ , 13 ₂ and transmitted to the detection end side through the optical fiber 7. Each output 2 from the main units 11 ₃ and 11 ₄ of the fault current direction determining device on the opposite side corresponds to the corresponding frequency transmitting unit.
12B ₃ and 12B ₄ convert to frequency signals of natural frequencies f ₃ ′ and f ₄ ′, and electric / optical converters 13 ₃ and 13 ₄ convert to unique optical signals, which are passed through the optical fiber 7 to the detection end side. Is transmitted.

At the detection end, the transmitted unique optical signal is converted into the electrical signals of the original natural frequencies f ₁ , f ₂ , f ₃ ′ and f ₄ ′ by the optical / electrical conversion unit 9
To convert. Converted natural frequencies f ₁ , f ₂ , f ₃ ′, f ₄ ′
The electrical signal of is subjected to frequency analysis to obtain a natural frequency f ₁ ,
_{f 2, f 3 ', f} 4' are arranged in the order of magnitude of the frequency of the electric signal, the natural frequency f _1, f ₂ as shown in FIG. 8 is shown in solid line, the natural frequency f ₃ ', f ₄ 'Is displayed as a broken line. By looking at this display, between the frequency f ₂ and f _3, or a f ₂ '
It can be seen that the fault point X exists between f ₃ ′, in other words, between the towers 4 ₂ and 4 _{3 on} which the fault current direction determination devices 6 ₂ and 6 ₃ are installed.

As shown in the lower row in the case of dual power supplies in Table-1, even when the polarity of the first half cycle of the fault current is (-), the output 2 is output, and when the polarity is (+), the output 1 is output. It is possible to detect X.

In the example of the upper stage in the case of the single power supply in Table-1, only the fault current direction determining devices main bodies 11 ₁ and 11 _{2 in} the fault current direction determining devices 6 ₁ and 6 ₂ on the left side of the fault point X shown in FIG. Output 1 indicating the direction of the fault current flow. Therefore, at this time, since the frequency analyzer 10 displays as shown in FIG. 9, it is possible to know where the accident point X is in the same manner.

In the example of the lower stage in the case of the single power source in Table-1, only the fault current direction determining devices main bodies 11 ₁ and 11 _{2 in} the fault current direction determining devices 6 ₁ and 6 ₂ on the left side of the fault point X shown in FIG. Output 2 indicating the direction of the fault current flow. Therefore, at this time, since the frequency analyzer 10 displays as shown in FIG. 10, it is possible to know where the accident point X is in the same manner.

Note that the paired frequency signal transmission units in FIG. 7 may have a structure in which one oscillator transmits the same frequency signal and the other transmits a double frequency signal with the oscillator being common.

[Advantages of the Invention] As described above, according to the transmission line accident section locating apparatus of the present invention, the following effects can be obtained.

According to claim (1), the optical fibers are arranged in parallel in the power transmission line, and the fault current direction determination devices are installed at appropriate intervals along the power transmission line, and these fault current direction determination devices flow to the overhead ground wire. Since the first half cycle of the fault current is detected and the flow direction of the fault current is determined based on its polarity, the fault current generated at the same time can be detected and the direction of the fault current at each determination position can be detected. I understand. Since a unique optical signal indicating the direction of the fault current as a result of this judgment and its judgment position is formed and sent to each optical fiber, the data at all judgment positions are collected in one place by the optical fiber. be able to. At the detection end of the optical fiber, the unique optical signal sent from this optical fiber is changed by the optical-electrical converter to a unique frequency whose frequency magnitude changes in sequence according to the judgment position along the line direction of the transmission line. It is converted into an electric signal, the frequency of this electric signal is analyzed by a frequency analyzer, and the display method is changed in the order of frequency and according to the direction of the flow of the fault current. You can know the position. In the present invention as described above, since the determination result can be transmitted without repeatedly applying a mechanical lateral pressure to the optical fiber, highly reliable detection can be performed for a long period of time.

According to claim (2), since the fault current direction determination device outputs one of two types of frequency signals indicating the direction of the fault current flow and the determination position, regardless of whether the transmission line is a double-sided power source or a single-sided power source, There is an advantage that it becomes possible to judge the accident section.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a first embodiment of an accident section locating device for a power transmission line according to the present invention, and FIG. 2 is a frequency signal output display diagram showing an example of frequency signal display of the device shown in FIG. 3 is a block diagram showing the internal structure of the fault current direction determination device of the device shown in FIG. 1, FIGS. 4 (A) and 4 (B) are fault current waveform diagrams, and FIG. 5 is the device of this embodiment. Explanatory drawing showing the flow of fault current in the case of dual power supplies, FIG. 6 is an explanatory diagram showing the flow of fault current in the case of a single power supply in the device of this embodiment, FIG.
FIG. 8 is a block diagram showing an internal configuration of a fault current direction determining device in a second embodiment of a faulty area locating device for a transmission line according to the present invention, and FIG. 8 is a frequency output display diagram in the case of dual power sources in the second embodiment. 9 and 10 are frequency signal output display diagrams in the case of a single power source in the second embodiment. 1 ... Power transmission line, 2 ... Overhead ground line, 3 ... Power transmission line, 4 ₁ to 4 ₄ ... Steel tower, 5 _{1 to} 5 ₄ ... CT, 6 _{1 to} 6 ₄ ... Fault current direction determination device, 7 ...
Optical fiber, 8 _{1-8 4} ... optical multiplexer, 10 ... frequency analyzer, 11
_{1 to} 11 ₄ ... Main body of fault current direction judgment device, 12 _{1 to} 12 ₄ , 12A ₁ to
12A _4, 12B ₁ ~12B ₄ ... frequency signal transmitting unit, _131-134 ... electro-optical conversion unit, 14 ... power supply, 15 ... load, _161-164 ... composition circuit portion.

Claims (2)

(57) [Claims] 1. A fault current according to the polarity of the first half cycle of the fault current flowing in the overhead ground wire of the transmission line, which is installed at an appropriate interval along the transmission line, and optical fibers arranged in parallel in the transmission line. A plurality of fault current direction determining devices for sending a unique optical signal indicating the direction of the fault current and the determination position, which is the determination result, to the optical fiber, and the detection end of the optical fiber. And an optical-electrical converter that is connected to the optical signal and converts the received unique optical signal into an electric signal of a natural frequency whose frequency magnitude sequentially changes corresponding to a determination position along the line direction of the power transmission line. A frequency analyzer connected to the output terminal of the optical-electrical converter to analyze the frequency of the electric signal and change the display manner in frequency order and in accordance with the flow direction of the fault current. Transmission Fault section locating system of the line. 2. The fault current direction determining device determines the flow direction of the fault current according to the polarity of the first half cycle of the fault current, and when the fault current flows in one direction of the overhead ground wire. Any one of the output 1 or the output 2; a main body of a fault current direction determining device that outputs the output 1 and outputs the output 2 when the fault current flows in the overhead ground wire in a direction opposite to the one direction. When a is output, a frequency signal is output that outputs a frequency signal of a natural frequency corresponding to that and indicating a determination position as a frequency signal whose frequency magnitude sequentially changes corresponding to the determination position along the line direction of the power transmission line. The fault section locating device for a transmission line according to claim 1, further comprising a unit and an electric / optical conversion unit that converts a frequency signal of the natural frequency into a unique optical signal.