JPH0583875B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a lightning strike area locating device for an overhead power transmission line that detects the lightning strike itself that induces a flash accident that interrupts the power transmission system, and particularly relates to a device that accurately determines the location of a lightning strike. . [Prior Art] Overhead power transmission lines or distribution lines are indispensable equipment for power transmission operations today, and accidents in these equipment can have a very serious impact on today's highly electrified society, and in some cases, Social functions in all areas may be paralyzed. For this reason, to protect overhead power transmission lines from lightning strikes, overhead ground wires are installed, and extremely reliable insulated support methods are adopted to prevent lightning strikes. We have not yet reached the point where accidents and flash-and-fall accidents have been completely eliminated. Therefore, in the event that such an accident occurs on an overhead power transmission line, etc., the next best challenge is to quickly determine the location where the accident occurred. Conventionally, the following three methods are mainly known as methods for detecting the location of a flash accident. In other words, the pulse radar method sends out a high-frequency pulse immediately after an accident occurs and determines the distance from the time it takes to receive the reflected wave at the accident point, the surge reception method uses the difference in arrival time of the accident surge to the measurement point, and determines the distance. This is an impedance method that locates the fault point based on the voltage and current at the time of the fault, and these so-called fault locators are used to find the fault location by determining the line length from the measurement point to the fault point. It's summery. These conventional fault locators are detection systems intended for flash accidents that cause power transmission system interruptions, and do not detect the lightning strikes themselves that cause these accidents. However, even if the power transmission system does not actually shut down, there is a risk that lightning will cause serious damage to the power transmission line, which will have a significant impact on future reliability. Therefore, it is important to take measures to prevent future serious accidents by quickly detecting lightning strikes and conducting thorough inspections. Therefore, conventional methods of detecting lightning strike points have been devised using such measures. That is, a method that detects lightning current flowing through an overhead ground wire or a steel tower and makes judgments based on the magnitude of the lightning current (for example,
142479), one that determines based on the direction of lightning current flow (e.g., JP-A-55-93067), and one that determines based on both the magnitude and direction (e.g., JP-A-54-107780). be. [Problems to be solved by the invention] However, depending on the line constant, it is not possible to clearly determine the location of a lightning strike from the magnitude of the lightning current, and even from the directionality of the lightning current, it is difficult to determine the reflected round trip waves from various parts of the transmission line. There was a problem that the lightning strike position could not be accurately determined due to the unavoidable influence of the superimposition of lightning. [Object of the Invention] An object of the present invention is to provide a lightning strike section locating device for an overhead power transmission line that can accurately detect a lightning strike section of a power transmission line regardless of the magnitude or direction of lightning current by solving the above-mentioned conventional problems. The goal is to provide the following. [Summary of the Invention] As shown in FIG. 1 corresponding to an embodiment, the configuration of the present invention in accordance with the above-mentioned object is such that a plurality of lightning current detectors 3 are spaced apart from each other along an overhead ground wire 2 of an overhead power transmission line 1. They are individually arranged. A determination circuit 4 is provided which determines which of the adjacent lightning current detectors the lightning current has reached first from the lightning current arrival information obtained from these lightning current detectors 3. This makes it possible to identify the lightning current detector where the lightning current from a lightning strike quickly reached, and to know that a lightning strike has struck a power transmission line near the identified lightning current detector. . [Example] An example of the present invention will be described below based on FIGS. 1 to 3. FIG. 1 shows a lightning strike area locating device for an overhead power transmission line according to the present invention. 1 is an overhead power transmission line, 5 is a transmission line tower, and 2 is an overhead ground wire, and this overhead ground wire 2 is provided with a lightning current detector 3. Lightning current detector 3
A plurality of (three in this embodiment) are arranged along the overhead ground wire 2 near each steel tower. These lightning current detectors 3 are connected to a determination circuit 4 via an optical fiber 6 to receive lightning current signals to prevent malfunctions due to electromagnetic induction noise. This determination circuit 4 has a function of determining which of the adjacent lightning current detectors 3 the lightning current has reached first. Here, the central steel tower 5 is called the own steel tower S, and the steel towers on both sides are called the adjacent steel towers R and L, and the signal from the lightning current detector 3 installed near the own steel tower is referred to as s, and the lightning current detectors installed on the left and right sides. Let the signals from 3 and 3 be r and l, respectively. FIG. 2 shows the circuit configuration of the lightning current detector 3. 7 is a lightning current detection coil, and the lightning current information flowing through the overhead ground wire 2 detected by this coil is voltage limited by the Zener diode 8. After that, a full-wave rectifier circuit 10 configured by a diode 9
The light is guided to the light emitting diode 11 through the light emitting diode 11, from which the light signal is extracted. Therefore, the lightning current information is voltage-limited to an appropriate value by the Zener diode 8, so it is accurately transmitted regardless of the size of the lightning current, and since it is full-wave rectified by the full-wave rectifier circuit 10, the lightning current information is The current is transmitted regardless of its direction. Moreover, since the lightning current energy is used as the transmission energy, the lightning current detector does not require an external power source. FIG. 3 shows the circuit configuration of the determination circuit 4 that determines the lightning current arrival information from each lightning current detector 3 that has been optically transmitted through the optical fiber 6. The determination circuit 4 includes a conversion section 12, first and second priority circuits 13 and 14, and an AND circuit 15.
The converting unit 12 includes three photoelectric converters 16 that photoelectrically convert optical signals s, r, and l respectively extracted from three sequentially arranged lightning current detectors into electrical logic signals (lightning electrical signals). The first priority circuit 13 uses an AND circuit 18 to AND the lightning electric signal r, which is one of the outputs of the photoelectric conversion section, and the second latch output inverted by the NOT circuit 17, and outputs the AND output to the first priority circuit 13. The latch circuit 19 outputs a judgment signal R corresponding to the lightning electric signal r, and the judgment signal R is inverted by a NOT circuit 17 to produce an inverted output, and a delay circuit 20 delays the second photoelectric conversion section. An AND circuit 18 performs an AND with the output lightning electrical signal s, and leads the AND output to the second latch circuit 21 that outputs the second latch output to generate one of the judgment signals corresponding to the lightning electrical signal s. S1 is output. Note that, like the delay circuit 20 described later, the above-described delay circuit 20 is a lightning current arrival information determination circuit 4.
This is to delay the own tower information by the optical transmission delay time from the adjacent towers R and L required to reach , and to increase the detection information by imparting simultaneity to subsequent processing. Furthermore, the second priority circuit 14 performs an AND operation between the lightning electrical signal s similarly delayed by the delay circuit 20 and the fourth latch output inverted by the NOT circuit 17.
The AND circuit 18 leads the AND output to the third latch circuit 22 to output another judgment signal S2 corresponding to the lightning electric signal s, and the NOT circuit 17 inverts and inverts this output S2. output and
The AND circuit 18 performs an AND with the lightning electric signal l, which is the third output of the photoelectric converter 12, and
The output is led to the fourth latch circuit 23 which outputs the fourth latch output described above, and outputs a judgment signal L corresponding to the lightning electric signal l. Then, the two steel tower determination signals S1 and S2 taken out from the first and second priority circuits 13 and 14
The determination circuit 4 is configured by connecting an AND circuit 24 that takes out the AND output of the . Now, in the above configuration, the power transmission line 1
When lightning strikes and the lightning current detector 3 detects lightning current, the detection information reaches the determination circuit 4 through the optical fiber 6. The lightning current arrival information s, r, and l that have reached the judgment circuit 4 are each converted into electrical logic signals by the photoelectric converter 12, and then passed through the AND circuit 18 to set the latch circuit to the "H" level. is inverted by the NOT circuit 17 and entered into another adjacent AND circuit 18, so one of the adjacent latch circuits in the priority circuit goes to "H" first.
When it reaches the "H" level, input to the other latch circuit is prohibited, so even if a lightning signal is input later than the others, that latch circuit will not go to the "H" level.
That is, the priority circuit blocks lightning current information that arrives with a time delay. Therefore, among the signals from the adjacent lightning current detectors 3, only the output of the priority circuit that arrived earlier in time is obtained as the "H" level. In this case, as can be seen from the following table, S-
When lightning strikes near the adjacent right steel tower R in the R section or near the adjacent left steel tower L in the LS section, the "H" level will be output to both priority circuits 13 and 14, so the judgment signals S1 and AND circuit 2 with S2
4 and performs an AND operation to unify the output, and ensure that only one output terminal is at the "H" level. In particular, the AND circuit 24
When the output reaches the "H" level, it can be determined whether lightning has struck the vicinity of the steel tower.

[Table] However, , , means the order in which the signals arrive.
In the above table, combinations such as, etc. are excluded because they do not physically exist. When there is a lightning strike on the power transmission line 1, the lightning current detector 3 closest to the lightning spot detects the lightning current before the others, and as the lightning current detector 3 moves away, the detection time is Become slow. Therefore, when detecting lightning current from sequentially arranged lightning current detectors 3, for example, when lightning strikes the first one,
This is because the second one is detected after the second one, and the second one is not detected as the third one. As is clear from the table above, by examining the levels of the three outputs R, S, and L of the determination circuit 4,
It is possible to determine which section was struck by lightning, and furthermore, which steel tower in that section was struck by lightning.
In this way, according to this embodiment, the determination is not made based on the magnitude of the lightning current or the direction in which it flows, but rather which of the adjacent lightning currents the lightning current has reached first, so the line constant There is no possibility that the location of a lightning bolt cannot be determined clearly due to the influence of the superposition of reflected back and forth waves from various parts of the power transmission line. In the above embodiment, the information from the lightning current detector 3 is transmitted through the optical fiber 6, but a composite overhead ground wire (OPGW) integrated with the overhead ground wire 2 is used for the optical fiber 6. Good too. Furthermore, although the case is shown in which lightning current detectors 3 are installed at three locations on the overhead ground wire 2, it is also possible to install more lightning current detectors 3 to extend the detection section. [Effects of the Invention] In summary, according to the present invention, one lightning current detector to which a lightning current quickly reaches from among a plurality of lightning current detectors is identified, and the power transmission line near the identified lightning current detector is Since you can know when a lightning strike has occurred, regardless of the size or direction of the lightning flow,
It is possible to accurately detect lightning strike sections on power transmission lines. Therefore, it exhibits an excellent effect of preventing serious accidents on power transmission lines.

[Brief explanation of the drawing]

FIG. 1 is an overall configuration diagram showing a preferred embodiment of a lightning strike section locating device for an overhead power transmission line according to the present invention;
This figure is a circuit diagram showing details of the lightning current detector shown in FIG. 1, and FIG. 3 is a circuit diagram showing details of the determination circuit. In the figure, 1 is an overhead power transmission line, 2 is an overhead ground wire, 3 is a lightning current detector, and 4 is a determination circuit.

Claims (1)

[Scope of Claims] 1. A plurality of lightning current detectors arranged apart from each other along the overhead ground wire of an overhead power transmission line, and which of the adjacent lightning current detectors is the lightning current reaching first? and an optical fiber that connects the lightning current detector and the determination circuit, and the lightning current detector includes a current detection coil that detects lightning current flowing through the overhead ground wire. , a rectifier circuit that performs full-wave rectification of the detection current of the coil, and a light emitting diode that converts the rectified output of the rectifier circuit into an optical signal, and the judgment circuit is connected to three lightning current detectors arranged in sequence. a converting unit that converts the extracted optical signals into first, second, and third lightning electrical signals;
and a first corresponding to the second lightning electrical signal input terminal.
and a second output terminal, and compares the two lightning electrical signals and outputs a determination signal to the output terminal corresponding to the input terminal that reached earlier among them; It has second and third output terminals corresponding to the input terminals of the second and third lightning electrical signals, and compares the two lightning electrical signals to determine which one of them corresponds to the input terminal that reached earlier. A second priority circuit that outputs a determination signal to an output terminal, and an AND output of the determination signals taken out from the second output terminals of the first and second priority circuits.
The first priority circuit includes a first lightning electrical signal, and an AND circuit.
The output of the second latch circuit, which will be described later, is ANDed with a signal obtained by inverting the output, the output is inputted to the first latch circuit, and the output of the first latch circuit is inputted to the first latch circuit of the first priority circuit. At the same time, the signal obtained by inverting the output of the first latch circuit and the second lightning electric signal delayed by the first delay circuit are ANDed, and the output is sent to the second latch circuit. and enter
The output of the second latch circuit is used as the second output of the first priority circuit, and the second priority circuit outputs a second lightning electrical signal delayed by a second delay circuit, and a fourth signal delayed by a second delay circuit. The output of the latch circuit is ANDed with the inverted signal, the output is inputted to the third latch circuit, and the output of the third latch circuit is inputted to the second latch circuit of the second priority circuit.
At the same time, the signal obtained by inverting the output of the third latch circuit and the third lightning electric signal are ANDed, and the output is inputted to the fourth latch circuit. A lightning strike section locating device for an overhead power transmission line, characterized in that the output is the third output of the second priority circuit.