KR20190050947A - Apparatus and method for surveying power lines - Google Patents

Abstract

Disclosed is a device for receiving a power line exploration signal for power line exploration. The device comprises: a magnetic field sensor detecting magnetic field signals generated by a power line, wherein the magnetic field signal is discarded by a load current and a current signal for exploration; a band-pass filter removing the magnetic field signal discarded by the load current among the magnetic field signals inputted to the magnetic field sensor to generate a magnetic field signal for exploration; and a digital converter digitizing a signal having passed through the band-pass filter. The device determines whether the magnetic field signal for exploration includes a predetermined signal, determines whether the same magnetic field signal for exploration is sensed after a predetermined time interval when the magnetic field signal for exploration includes the predetermined signal, and determines that the magnetic field signal for exploration has been sensed when the same magnetic field signal for exploration is sensed after the predetermined time interval. Even after filtering, signals similar to current pulses for path seeking are included in a large amount such that exploration signals cannot be accurately distinguished only with a simple detection of the maximum value. Accordingly, a method for detecting an exploration signal synchronized with a current signal generation time is invented as follows. The method detects signals only in a time zone, in which signal pulses are generated, and compares the signals, not determining by comparing the entire signals unnecessarily. The conventional method has measured magnetic field signals measured in one-cycle units (for 16.7 msec) and compared the measured magnetic field signals with previously measured values to determine the presence or absence of exploration signals. The present invention can improve accuracy of a path exploration, and reduce effects of environments.

Description

TECHNICAL FIELD [0001] The present invention relates to a power line inspection apparatus,

The present invention relates to a surveying technique for grasping the installation (buried) route of a power line that is buried or hidden in the ground and can not be visually recognized, or for identifying a line (configuration) such as power line, And more particularly, to a method of exploring a place where a magnetic field signal is affected by a load current or the like in a power transformer or the like in which power lines and the like are concentrated.

In order to explore the installation route of the power line that is buried or concealed in the ground and can not be visually confirmed, the inventor of the present invention has found that the load side of the power line in operation in the Korean Patent No. 10-0778089 (underground low voltage line survey system and method at the installation site of the multi- (Current impulse) signal using a terminal device, and a magnetic field signal induced by the flowing current is detected by contacting the surface of the power line on the intermediate path of the power line or by detecting the magnetic field signal on the ground in a non- We introduced a system and method for grasping the buried path of a surveying device, grasping a master value installed in a transformer (power source), and transmitting the power line information to a terminal device to grasp the circuit configuration.

SUMMARY OF THE INVENTION The present invention has been made in response to the above-described background art, and an object thereof is to provide an apparatus and method for accurately searching a buried path of a power line through a magnetic field signal for probe use.

An apparatus for receiving a power line probe signal for power line probing according to an embodiment of the present disclosure for realizing the above-described problems is disclosed. The power line probe signal receiving apparatus includes a magnetic field sensor for detecting a magnetic field signal generated from a power line, the magnetic field signal being generated by a load current and a probe use current signal, And a digital converter for digitizing a signal that has passed through the band filter, the method comprising: determining whether the tom seek magnetic field signal is composed of a predetermined signal; Determining if the same probing magnetic field signal is detected after a predetermined time interval and if the same probing magnetic field signal is detected after a predetermined time interval, if the probing magnetic field signal is detected .

Improved path probe accuracy and minimized ambient effects

Figure 1 is a schematic diagram of the path probe configuration
[Fig. 2] shows the comparison between the voltage waveform and the current probe signal generation time
[Fig. 3] shows a comparison of the downward upward direction zero crossing time
[Figure 4] shows a comparison between a 0 value and a 1 value
[Fig. 5] shows a waveform of a probe signal included in a large current load
Fig. 6 is a graph showing a value obtained by interpreting a probe signal contained in a large current load
[Figure 7] shows the comparison of the phase current and the neutral current waveform
[Figure 8] shows the waveform of the neutral current
[Figure 9] shows the phase change order of the neutral line current
[Fig. 10] shows a pulse analysis example included in the neutral current
[Fig. 11] shows an example of a probe signal input stage change (improvement) circuit example
[Fig. 12] shows the relationship between the phase current and the neutral current waveform
[Fig. 13] shows an example of a method of classifying a probe signal when the synchronization is not performed (prior art)
[Fig. 14] shows a case in which the peak waveform of the load current is continuously generated
[Fig. 15] shows a time synchronization frame description for improving the accuracy of the detection of the probe signal
FIG. 16 is a diagram for explaining a method of discriminating a probe signal by comparing peak values (when it is not a signal)
[FIG. 17] is a diagram for explaining a method of discriminating a probe signal (in the case of a signal)
[Fig. 18] is a diagram for explaining the polarity classification method of the probe signal

In order to probe the power line installation (buried) path on the ground or the circuit configuration information in the transformer, manhole, etc., it is crucial how accurately the magnetic field signal induced by the generation of the current signal can be detected near the power line or on the ground .

First, FIG. 1 shows an example of a configuration of a device for a power line installation path and a line search in the existing technology. That is, in order to probe the circuit configuration and the installation path of the power lines connected to the transformer 10 to supply power, the power supply side power supply side 20 and the load side side terminal device 30 are connected to the power supply line 11 Connect to the neutral line (12) to allow a signal with a scan current of 60 ~ 100A to flow in a very short time (0.5 ~ 1.5 msec). A magnetic field signal 32 is formed along the power line in accordance with the probe use current flow 31 and is detected by a path search device (not shown) that detects the installation (buried) path of the embedded power line using a sensor such as a ferrite coil 40) and ferrite coils or Rogowski coils (22) are contacted to the surface of the power line without removing the insulation from the exposed power line, such as a transformer or a manhole, so as to grasp the configuration information of the power line, (Configuration) search 21 using a coil 22 or the like.

FIG. 2 illustrates generation of the test current 104. FIG. The power frequency (50 or 60 Hz) voltage signal waveform 101 includes an uplink zero crossing point 106 and a downlink zero crossing point 105 at which the load current becomes minimum (0) The generation of the ramp-up current-use pulse 104 is greater than the maximum point 103 of the load current waveform 102 to detect the magnetic-field signal at the path probe or master and detect the magnetic field signal at random (arbitrary) (16.7 msec at 60 Hz), it is possible to easily distinguish between (1) and (2) where the probe signal is present. [Figure 3] shows the generation relationship of the downward and upward zero crossing points and the probe current pulse.

However, when the magnitude of the test current 104 is larger than the load current 102 as shown in FIG. 4, one cycle (16.7 msec, at 60 Hz) at a random (arbitrary) (1, 0) of the signal value by comparing the measured value of the accumulated value of the magnetic field signal with the value of the previous cycle.

However, the above method can clearly distinguish the probe signal when the load current size is smaller than the probe current and there is only one power line. However, when a plurality of power lines are concentrated such as near a transformer or a manhole, It can not be applied where complex waveforms appear

The following is a waveform that measures the magnetic field signal near the transformer. The peak point of the yellow point is continuously appearing with the same value of + -. In this case, the magnetic field signal due to the probe current is not very large and can be accurately explored only if it is analyzed in detail.

In order to prevent the error that occurs when detecting the magnetic field signal induced by adding the load current and the probe current signal as described above and detecting the existence of the probe signal,

Changed and added functions

1. Remove load current

2. Time synchronization function

First, the magnetic field signal value derived from the load current was removed in order to compare only the generated magnetic field signal generation period by the probe use current signal generated by the terminal without comparing the entire magnetic field signals in the path probe

As described above, in the conventional technology, the magnetic field signal induced by the sum of the load current and the probe current signal is compared every cycle, and if there is a change in the signal value, it is detected as 1 or 0. However, in order to eliminate the magnetic field signal induced by the load current (60 Hz to 300 Hz) in order to solve the problem, the detection signal is detected between the input signal and the digital converter A 600 Hz bandpass filter was added to detect only the magnetic field signal induced by the probe current signal.

After filtering, the input signal of the digital converter (ADC) of the path probe is as shown below, and the sine wave of the 60 Hz power frequency is removed and only the high frequency component of the 600 Hz band is shown. Where the digital converter (ADC) can digitize the signal passed through the bandpass filter. More specifically, the digital converter (ADC) may perform digitization to divide the probing magnetic field signal generated by the bandpass filter on a cycle-by-cycle basis and convert each cycle to a digital number including signal 1 or signal 0. Here, the output unit of the digital converter may be one bit.

In order to improve the accuracy of the detection signal detection, we synchronize the signal generation time with the signal detection time in the following order and minimize the influence of other signals by reducing the detection time

1. Connect the terminal to the power line and switch to the path probe current pulse generation mode. More specifically, a terminal device for transmitting a power line probe signal can be connected to a power line. Then, the power frequency flowing through the power line through the terminal device can be measured. In addition, the terminal device can generate a probe magnetic field signal and transmit it on the power line.

2. A terminal device for transmitting a power line probe signal can generate a pattern on a current pulse by generating or not generating a current pulse based on the waveform of the power frequency. More specifically, the terminal device can identify a downward zero crossing point passing 0V in the negative direction and an upward zero crossing point passing in the positive direction in the waveform of the power frequency. Then, the terminal device can generate a current pulse at the downward zero crossing point. For example, the terminal device generates a current pulse of 1 to 1.5 msec (signal 1) close to the downward zero crossing point of the power frequency and does not occur (signal 0) in the next cycle (1T = 16.7 msec or later) In the next cycle, a current pulse is generated (signal 1) to generate a 1010 signal once. Then, after 1.9 seconds (in the case of 114 cycles and 60 Hz), it sends again the 1010 signal and the additional 3 zeros so that the detection signal can be detected. The generation of the above-described current pulse is only an example, and the present disclosure is not limited thereto.

3. In the noisy region, the wrong peak may occur. Therefore, the magnetic field sensor of the route probe detects the first peak value of the received magnetic field signal and confirms that the same signal continues in the next cycle. If the same peak value is continuous, this peak point is ignored.

That is, since the peak of FIG. 16 repeats at the next cycle (D), it is ignored and it is checked whether there is a next peak in the third peak.

4. Detect the first peak of the magnetic field generated by the current pulse near the power line from the path probe in the peak.

However, even after the filtering, since the signals including the pulse current pulse are still contained in a large amount, it is impossible to accurately discriminate the probe signal only by the maximum value detection. Thus, the probe signal detection method synchronized with the current signal generation time was invented as follows

It is not necessary to compare all of the signals unnecessarily, but to detect signals only during the time period in which the signal pulses are generated, and to compare them

In the previous method, the signal of the magnetic field measured in one cycle (for 16.7 msec) was measured and compared with the previous measurement value to determine the presence of the probe signal

This program is the operation program of the path finding device that detects the installation (buried) path by detecting (detecting) the magnetic field signal generated by the current impulse signal through the power line from the ground to the power line installation (buried) path. Previously, only the peak value was compared at zero crossing point of each cycle to determine 1 or 0. However, in this program, the Ta function that compares the average value and the T function that compares the peak value were alternately used for comparison.

1. After the initialization of the device, it is possible to synchronize the starting point of the average value for comparison in synchronization with the scanning period (cycle) by the initial current impulse signal. More specifically, the digital converter can determine whether the probing magnetic field signal is composed of a predetermined signal and digitize it. Then, it is possible to determine whether or not the first pulse signal of the probing magnetic field signal output from the digital converter is recognized. Digital converter can detect the first peak value of the magnetic field signal and confirm that the same peak value is continuous in the next period. Then, the digital converter can ignore the first peak value when the same peak value is continuous. Further, when the successive peak values are different, the digital converter can convert a high peak value among successive peak values into signal 1 and output it. Accordingly, the digital converter can match the comparison average value starting point by the starting point of the peak value at which the signal is output as 1.

2. Current impulse signaling occurring every 1.9 seconds In order to synchronize the signal, it is detected from 1.9 sec -7Cycle time point after detection of the first detected pulse signal. If 7bit value is 0101000, it can be recognized as a probe signal. have. More specifically, when the first pulse signal is recognized in the digital converter, it can be determined whether the pulse signal detected during a predetermined time interval is a predetermined signal pattern. When a predetermined signal pattern is detected in the pulse signal, it can be determined that the probing magnetic field signal is detected. Digital converter can recognize the digitized signal value for each cycle for a predetermined time interval from the signal output to 1 in the digital converter. For example, from the point where the first recognized pulse signal is at 1, we can check the 7 bit values output from the digital converter for 1.9 seconds corresponding to 7 cycles at 60 Hz. When 7 bits is 0101000, it can be judged that the probing magnetic field signal is detected. The specific numerical description of the detection determination of the above-described probe magnetic field signal is only an example, and the present disclosure is not limited thereto.

3. The presence or absence of the signal can be determined by comparing the magnitude of the mean value with the previous value, and the value of the signal magnitude can be expressed as the peak magnitude value. The digital converter according to an embodiment of the present disclosure can determine the value of the magnetic field signal to be 0 or 1 based on the magnitude of the average value of the magnetic field signal for one cycle. Alternatively, the value of the magnetic field signal may be determined as signal 1 or signal 0 based on the peak value of the magnetic field signal at the zero crossing point of each cycle.

Claims (1)

A power line probe signal receiving device for power line probing,
A magnetic field sensor for detecting a magnetic field signal generated by a power line, the magnetic field signal being generated by a load current and a tomizing current signal;
A band pass filter for removing a magnetic field signal induced by a load current among the magnetic field signals input to the magnetic field sensor to generate a seek magnetic field signal; And
A digital converter for digitizing a signal passed through the bandpass filter;
Lt; / RTI >
Determine whether the probing magnetic field signal is comprised of a predetermined signal, determine if the same probing magnetic field signal is sensed after a predetermined time interval when configured with a predetermined signal, Wherein when the same probing magnetic field signal is detected, it is determined that the probing magnetic field signal is detected,
Power line probe signal receiving device.

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