JPH01320481A - Thunderbolt detecting system for electricity transmission line - Google Patents

Abstract

PURPOSE:To detect a thunderbolt by installing sensors to detect signals for thunder surge on the constituting elements of an electricity transmission line with a distribution in the direction of the line and comparing the signals of the sensors on two different points. CONSTITUTION:The thunder surge detecting sensors 1 are installed on an overhead grounding line A and near the positions of steel towers numbered. Among these sensors 1, the distances between the steel towers #49-#7, #7-#16, #16-ST are divided to each block, and discriminating parts 2 and transmitting devices 3 are provided in each block. The thunder surge waveforms transmitted from each sensor 1 are entered to the discriminating parts 2 wherein converted to the 60Hz to make phase comparisons. An existence of the thunderbolt between the adjacent sensors 1 is thereby decided and the data are sent to the devices 3 in each block. The data on the devices 3 are sent to a central wherein a final decision for the thunderbolt is made from the phase distribution on the entire line.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a lightning strike detection system for an overhead power transmission line, which detects lightning strikes on the line and locates the lightning strike point.

(Prior art and problems to be solved) When an accident occurs on an overhead power transmission line due to a lightning strike or other cause, conventional technologies include one-type pulse radar, surge reception method, impedance There are methods etc.

With these conventional technologies, even if a lightning strike occurs on a power transmission line, if it does not cause an accident, it is not detected and overlooked, and if an accident occurs, an inspection will determine whether it was caused by lightning or not. There were cases in which it was possible to determine whether or not the

(Means for Solving the Problems) The present invention provides a lightning strike detection system for overhead power transmission lines that detects lightning strikes and locates lightning strike points in order to monitor the occurrence of damage to overhead power transmission lines due to lightning strikes. Its feature is that sensors for detecting lightning surges are attached to components of the power transmission line distributed in the line direction, and lightning strikes are detected by comparing the signals of the sensors at at least two different points.

FIG. 1 is an explanatory diagram of the basic principle of the lightning detection system of the present invention.

In the drawing, (A) is an overhead ground wire, which is one of the components of the power transmission line, and (Ia) (16) (IC) is an overhead ground wire (A).
) Light C for detecting lightning surge installed in the direction of the railway line
Adjust the output using a detection sensor such as T so that the output is in a fixed direction relative to the direction of the current.

(2) is a discrimination unit, which is a detection sensor (Ia) (16) (
A receiving PD (2
1), signal amplification circuit (22), filter circuit (2)
3) Amplification circuit for the filtered signal (24)
, a phase comparison circuit for two signal waveforms (25), a signal level comparison circuit (211i), a device m that collectively judges the compared data and transmits it to the transmission device (3).
27).

(3) is a transmission device that transmits the judgment result of the compared data to the central processing unit.

(Function) The surge current flowing through the overhead ground wire (A) is detected by the detection sensors (Ia), (16), and (Ic) such as optical CT and transmitted to the discrimination section (2) for data processing.

The surge signals of the detection sensors (la) (+6) (lc) are received by each PD (21) and sent to the amplifier circuit (
22), the signal is amplified to an appropriate signal level, and passed through a filter circuit (23) to extract only low frequency components around 10 Hz, for example. Next, the level and phase difference of the obtained signal are compared by a level comparison circuit (26) and a phase comparison circuit (25), and the signal exceeds a certain level and a predetermined phase difference, for example, 90' to 2700. If there is a phase difference, it is determined that there has been a lightning strike, and the signal is sent to the transmission device (3), from where it is transmitted to the central processing unit.

The effect of the filter by the filter circuit (23) is that when an impulse is input, for example, fiO
Low frequency components such as Hz components can be extracted, and the output waveform characteristics appear with a certain delay time depending on the polarity of the input impulse. As such a filter, a normal C-R filter or an active filter is used, and the specific frequency is around 60 Hz or 50 Hz, which is a commercial frequency.

The advantage of doing this is that if you try to process the surge at a high speed, the processing circuit will be required to be fast, but if you process the surge as a low frequency component such as 60Hz, it will be easier to determine the polarity and the phase. This makes it easier to judge. As a result, a circuit with a slow processing speed can be used, and power consumption can be reduced. In other words, if the characteristics of the optical CT that received the surge are even slightly different, it cannot be determined that there is a phase difference when compared at the same time as shown in Figure 2 (A), whereas for BGHz, there is a difference in phase as shown in Figure 2 (A). Even if there is a slight deviation in the phase difference determination element, it can be easily dealt with.

Also, as a circuit for phase comparison, the difference between zero-crossing signals of two waveforms is observed.

Further, by using the phase comparison described above in conjunction with accident detection that detects follow-on current in the event of an accident, it is possible to distinguish between an accident and a lightning strike, depending on whether there is any trip information at the substation.

In this case, the data for a certain period of time is monitored by storing the surge waveform and its follow-on current through A/D conversion, etc., and based on the pattern shown in Figure 3, it is possible to determine whether or not there has been an accident. A decision can be made without receiving a signal.

(Embodiment) FIG. 4(A) is an explanatory diagram of a specific example in which the detection system of the present invention is applied to an overhead ground wire, and FIG. 4(N) is a system diagram thereof.

・Lightning surge detection sensor 0) such as optical CT is installed on the overhead ground wire (A) near the steel tower NO shown in the figure (shaded).
Among these detection sensors 0), steel towers #43 to #7,
#7 to #IG, #16NST are divided into blocks, and each block is equipped with a discriminator (2) and a transmission device (3).
) is installed.

The lightning surge waveform transmitted from each detection sensor (1) enters the discriminator (2), where it is determined by the method described above.
By replacing it with the 0Hz component and performing phase comparison,
The presence or absence of a lightning strike between adjacent detection sensors (1) is determined and sent to the transmission device (3) of each block. Data from each transmission device (3) is sent to a solid device, and a lightning strike is finally determined based on the phase distribution of the entire line.

(Effects of the Invention) As explained above, according to the lightning detection system of the present invention, steep surges such as lightning can be treated as low frequency signals, so lightning strikes or induced lightning are always detected like on overhead power transmission and distribution lines. It is effective as a system for locating lightning strike points or sections in areas exposed to lightning. In particular, it is extremely effective for monitoring deterioration and damage in overhead power transmission lines, where communication lines are constructed horizontally using optical fiber composite overhead ground wires and require high reliability.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of the basic principle of a system for detecting lightning strikes on power transmission lines according to the present invention. FIGS. 2A and 2B are explanatory diagrams of phase comparison using low frequency components. FIG. 3 is a pattern diagram of an example of accident judgment. FIG. 4(A) is an explanatory diagram of a specific example in which the detection system of the present invention is applied to an overhead ground wire, and FIG. 4(B) is a system diagram thereof. A... Overhead ground wire, is fa, IJx lc... Lightning surge detection sensor, 2... Discrimination section, 21... Receiving PD, 22... Amplifying circuit, 23... Filter circuit, 24...Amplification circuit, 25...Phase comparison circuit, 2
6...Level comparison circuit, 27...Storage device, 3...
・Transmission device. Dice 2wJ (U) Aoi 3rd

Claims (4)

[Claims] (1) A power transmission line characterized in that sensors for detecting lightning surge signals are installed on components of the power transmission line distributed in the line direction, and lightning strikes are detected by comparing the signals of the sensors at at least two different points. lightning detection system. (2) Several hundred Hz from the signal detected by the sensor
2. The lightning strike detection system for a power transmission line according to claim 1, wherein the following low frequency components are extracted and the phases or amplitudes of the low frequency components are compared. (3) The lightning strike detection system for a power transmission line according to claim (1), characterized in that all sensors are monitored at one location or each sensor is divided into blocks for monitoring. (4) Claim (1) characterized in that the data within a certain period of time is monitored by storing the surge waveform and its follow-on current, and the presence or absence of an accident is determined without receiving a trip signal from the substation. ) method for detecting lightning strikes on power transmission lines.