JPS63122965A - Aerial ground wire current sensor for overhead transmission line - Google Patents

Abstract

PURPOSE:To achieve a higher processing function of an aerial ground wire current sensor, by detecting a peak value of an aerial ground wire current as frequency information and a phase thereof as time information. CONSTITUTION:A GW (aerial ground wire) current sensor is made up of a CT1, a peak holding circuit 11, a waveform conversion circuit 12, a V/F conversion circuit 13, an AND circuit 14, a current amplification circuit 15, an LED 4 and an optical fiber 5. Then, an output of the CT1 is divided in two and one part thereof is introduced to the circuit 11 which outputs a pulse for detecting a peak while the other part thereof is done to the circuit 12 which outputs a high level when the sine wave of the input is positive while doing a low level when it is negative. Then, the circuit 11 is set or reset by an output of the circuit 12 and an AND output is amplified 15 in the current as obtained with the circuit 14 between a signal obtained by frequency conversion of an output of the circuit 11 with the circuit 13 and a peak detection pulse 17 of the circuit 11. The LED 4 emits light by an output thereof and an output of a frequency proportional to a current value of the GW is transmitted to a multiplex transmitter 6a through an optical fiber 5. This enables detection of the current value and the phase of a GW current thereby achieving a higher processing function.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field 1] The present invention relates to an overhead ground wire current sensor for an overhead power transmission line.

[Prior Art] An overhead ground wire (hereinafter referred to as GW) current sensor is described in detail in 1985 IEEJ National Conference Paper +1fi1068.

This method uses a current transformer (CT) as shown in Figure 3.
1, a Zener diode 2, a diode bridge 3, and a light emitting diode (LED) 4. The principle of this method is that the negative pole side of the CTI output is connected to the Zener diode 2.
is cut to a constant level, reversed to the positive side by diode bridge 3, and by calibrating the current peak value originally on the positive side using this constant level value, a light output with temperature fluctuations removed from the output of LED 4 is obtained. That's true.

That is, as shown in FIG. 4, the peak value -a,
A current -a/b is obtained at a constant level value.

This optical output is guided through an optical fiber 5 to a multiplex transmission device 6 at the bottom of the tower, and is subjected to O/E conversion by an O/E conversion circuit 7, and A/D conversion.
After A/D conversion by the conversion circuit 8, the multiplex transmission circuit 9 transmits the signal to a remote central monitoring station via the composite overhead ground wire (OPGW) 10, where the waveform is analyzed and the above-mentioned calibration is performed.
The W lightning current peak value is being determined. At this time, the GW lightning current can be changed from the zero-crossing point of the waveform (see Fig. 4).

[Problems to be Solved by the Invention] Although the purpose of the above conventional technology is to detect the peak value and phase of the GW lightning current, since the entire current waveform is output, the information to be multiplexed and transmitted is In many cases, when the line length increases and the number of sensors decreases, normal transmission equipment will no longer be able to transmit data.

The present invention has been made in view of the above points, and the present invention has been made in view of the above points.
It is an object of the present invention to provide an overhead ground wire current sensor for an overhead power transmission line that enables improvement in performance.

[Means for solving the problem] The above purpose is to connect the overhead ground wire current sensor to a current transformer installed on the overhead ground wire, a beak φ hold circuit, a waveform conversion circuit, a V/
A peak hold circuit consisting of an F conversion circuit, an AND circuit, a current amplification circuit, a light emitting diode, and an optical fiber, which divides the output of the current transformer into two, and one of which has the function of outputting a pulse when a peak is detected. The other side is led to a waveform conversion circuit that outputs a high level when the input sine wave is positive, and a low level when it is negative.The output of the waveform conversion circuit sets/resets the peak hold circuit, and the output of the peak hold circuit The AND output of the frequency-converted signal by the V/F" conversion circuit and the peak detection pulse of the peak hold circuit is amplified by the current amplification circuit, and this output causes the light emitting diode to emit light. This is accomplished by transmitting an output with a frequency proportional to the ground wire current value via an optical fiber to a multiplex transmission device.

[Operation] As mentioned above, the GW lightning current peak value is used as frequency information,
Also, since the phase is detected as time information, G
The current value and phase of W'l flow can now be detected,
Compared to the conventional example in which all waveforms are sampled, the number of transmissions m is extremely reduced, signals from a large number of sensors can be multiplexed and transmitted, and the processing function of the GW current sensor can be improved.

In other words, since the output of the GW current sensor is obtained as a frequency, it is not affected by temperature fluctuations or changes over time in the light output of the LED. Furthermore, since the peak value of the GWI flow can be measured in real time, the phase of the current can also be measured by measuring the time when the current reaches its peak.

In addition, the output of this GW current sensor is
The E conversion circuit and the frequency counter circuit can convert the input current value into a value proportional to it in real time, and the multiplex transmission circuit only needs to transmit this converted value, so that the number of transmissions M becomes extremely small.

[Example] The present invention will be described below based on the illustrated example. FIG. 1 shows an embodiment of the invention. It should be noted that the same parts as those in the prior art have been given the same reference numerals, so their explanations will be omitted. In this embodiment, the GW current sensor is installed at GW, CT1, peak hold circuit 11, waveform conversion circuit 12, V/F conversion circuit 13, AND circuit 14, current amplification circuit 15, LE
Consists of D4 and optical fiber 5 (), output of CT1 is 2
One is a peak hold circuit 11 with a function of outputting a pulse when a peak is detected, and the other is a high level when the input sine wave is positive, and a low level when it is negative. The waveform conversion circuit 1 is guided to the waveform conversion circuit 12.
The peak hold circuit 11 is set/reset with the output of 2, and the output of the peak hold circuit 11 (peak output 1
6) is subjected to wave number conversion by the V/F conversion conversion circuit 13 and the peak detection pulse (peak detection output) 17 of the peak hold circuit 11, and the AND output via the AND circuit 14 is current amplified by the current amplification circuit 15. This output causes the light emitting diode 4 to emit light, and the output at a frequency proportional to the current value of the overhead ground wire is sent to the multiplex transmission device Vl 6 via the optical fiber 5.
The data is now transmitted to a.

GW by doing this? It is possible to obtain a GW current sensor for an overhead power transmission line that can detect the current value and phase of the li current and has improved processing functions.

In other words, the output of CT1 is divided into two, and one is the peak
A hold circuit 11 holds the peak value, and the peak value (peak output 16) is converted into a wave number signal by a V/r conversion displacement circuit 13. The output of the other CT1 is sent to the waveform conversion circuit 12.
When the output of CT1 is positive, it is converted to a high level waveform, and when it is negative, it is converted to a low level waveform. This output causes the peak hold circuit 11 to hold the peak when it is at a high level.
By resetting when it is at a low level, the peak current value for each cycle of the commercial frequency can be obtained for that cycle. Peak detection output 17 of peak hold circuit 11
generates a pulse when the state of the peak hold circuit 11 changes from peak detection to peak hold. The AND circuit 14 is a peak detection output 17 and a V/F conversion transformation circuit 1.
Outputs 3 logical product. This output is amplified by the current amplification circuit 15, converted to optical output by the LED 4, and transmitted by the optical fiber 5. In this case, the waveforms of the CT ratio output waveform conversion circuit output, peak hold circuit output, peak detection signal, V/F conversion circuit output, and LED output, which are the output waveforms of each circuit, are shown in Figure 2. .

As shown in the figure, only the CT output waveform is a sine wave, and the others are pulse waveforms.

When the pulse width of peak detection output 17 is decreased, LED 4
The light emission time is also shortened, and power consumption is also reduced. For example, 1m5ec<leprosy is appropriate.

Since the magnitude of the GWTi current usually changes by two orders of magnitude between normal and faulty conditions, the dynamic range of the V/F conversion displacement circuit 13 is also required to be about two orders of magnitude. For example, GW lightning current 5 to 50
When the voltage changes to 0A, the V/F conversion conversion circuit 13 power is 10KH.
z to 1M1-1z is appropriate.

Since the output of this GW current sensor is thus obtained in terms of frequency, it is not affected by temperature fluctuations or changes over time in the light output of the LED 4. Furthermore, since the GW lightning current peak value can be measured in real time, the phase of the current can also be measured by measuring the time when the current reaches its peak.

In addition, the output of this GW current sensor is
The wave number counter circuit 18 can convert the input current value into a value proportional to it in real time. Multiplex transmission circuit 9
It is only necessary to transmit this converted numerical value, and the amount of transmission is extremely small.

Further, normally, this GW current sensor is located at the top of the steel tower, and the output of the multiplex transmission device 6!6a is transmitted to a distant central monitoring station at 0PGW10.

As described above, according to this embodiment, since the GW lightning current value and phase are detected, the number of transmissions m is extremely small compared to a method in which all waveforms are sampled and transmitted.

Therefore, signals from a large number of sensors can be multiplexed and transmitted. Furthermore, since the LED 4 is emitted, power consumption is low. Furthermore, since the output is obtained in frequency, the LED
It does not receive the output fluctuation III of 4.

[Effects of the Invention] As described above, the present invention provides an overhead ground wire 'r! The processing function of the first-flow sensor has been improved, and it is now possible to obtain a first-flow sensor for an overhead power transmission line whose processing function has been improved.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing the configuration of an overhead ground wire current sensor of an embodiment of the overhead ground III current sensor for an overhead power transmission line according to the present invention;
FIG. 2 is a time chart diagram showing output waveforms of each part of one embodiment, FIG. 3 is an explanatory diagram showing the configuration of a conventional overhead ground wire current sensor for an overhead power transmission line, and FIG. It is an output waveform diagram of a ground wire current sensor. 1: Current transformer (CT), 4: Light emitting diode (LED), 5: Optical fiber, 6a: Multiplex transmission device, 11: Peak hold circuit, 12: Waveform conversion circuit, 13: V/F Conversion circuit, 14: AND circuit, 15: Current amplification circuit, 16: Output of peak hold circuit (peak output) 17
:Peak detection pulse (peak detection output). Figure 2 11 m...-LED playback

Claims (2)

[Claims] (1) In an overhead ground wire current sensor for an overhead power transmission line that is installed on an overhead ground wire and detects a current flowing through the overhead ground wire in the event of a failure and transmits an optically converted signal to a multiplex transmission device, the overhead ground wire The current sensor includes a current transformer installed on the overhead ground wire, a peak hold circuit, a waveform conversion circuit, a V/F conversion circuit, an AND circuit, a current amplification circuit, a light emitting diode, and an optical fiber, and Divide the output into two,
Leading one end to the peak hold circuit which has a function of outputting a pulse when a peak is detected, and the other end to the waveform conversion circuit which outputs a high level when the input sine wave is positive and a low level when it is negative, A peak hold circuit is set/reset with the output of the waveform conversion circuit, and the output of the peak hold circuit is frequency-converted by the V/F conversion circuit, and the peak detection pulse of the peak hold circuit is combined with the AND signal. The current amplifying circuit amplifies the AND output through the circuit, causes the light emitting diode to emit light with this output, and transmits an output with a frequency proportional to the current value of the overhead ground wire to the multiplexed transmission via the optical fiber. An overhead ground wire current sensor for an overhead power transmission line, characterized in that the current sensor is configured to transmit information to a device. (2) The peak detection signal of the peak hold circuit is
An overhead ground wire current sensor for an overhead power transmission line according to claim 1, which is adapted to detect phase information of the overhead ground wire current as pulses that are sufficiently shorter than a commercial frequency.