JP3333734B2 - Fault location method for power system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for locating a fault in a power system such as a high-voltage distribution line, and more particularly to a method for locating a fault in a power system for specifying the position of a fault.

[0002]

2. Description of the Related Art When an accident occurs in a high-voltage distribution line or the like and a power outage occurs, the position of the accident must be immediately identified (located) in order to be able to quickly perform the restoration work. 2. Description of the Related Art Conventionally, there are specific examples listed below as an accident point location method after a power failure. (I) After applying a high DC voltage to a distribution line in a power outage state after the occurrence of an accident and firing the accident point, a change in impedance is measured by a bridge circuit. If there is a branch, the branch sections that have been sequentially separated are measured while performing the separation operation of the branch part. After limiting the section, paying attention to the fact that the impedance changes at the fault point, a pulse voltage is incident from one end of the cable, and the fault point is determined from the time difference at which the reflected wave generated at the fault point reaches the incident point.

[0003] In the case of a system having many branches and a large number of installation equipment such as pole transformers such as an overhead line, it is necessary to apply a DC high-voltage pulse voltage to the line and measure the current flowing into the accident point. This is performed while moving sequentially in section units, and the fault point is determined from the presence or absence and direction of the current. (Ii) As an orientation method in a live state, an accident signal detection device is installed at a plurality of points on a measurement line, and an accident point is calculated from a difference in signal arrival time at each accident signal detection device. In the case of this accident point locating method, a signal is transmitted to a master station which performs processing for locating an accident point in order to obtain synchronization between the respective accident signal detectors, collect measurement results from each of the accident signal detectors, and transmit the signals. Therefore, a signal transmission medium is laid. (iii) In the fault point locating method disclosed in JP-A-7-287045, signal detection devices are connected to both ends of a measurement section of a high-voltage distribution system having a fault point, and a reference signal is transmitted from one of the signal detection devices. Detecting the reference signal and the discharge pulse from the accident point, obtaining the times t1 and t2 from the time of receiving the reference signal to the time of detecting the discharge pulse in each signal detection device, and calculating the time difference (t1-t2 or t2-t1). From the accident point.

[0004]

However, according to the conventional method for locating an accident in an electric power system, in the case of the locating method (i), the operation of disconnecting the track is required, which requires a great deal of labor and the movement of the vehicle. There is a problem that the working time becomes longer due to the time and repeated measurement. Furthermore, it is not possible to measure while the power system is in a live state, and it cannot be used for locating a successful retransmission accident.

In the case of the accident point locating method (ii), (i)
In the same manner as described above, the exploration time becomes longer due to the sequential measurement, and the work of lifting and lowering the electric pole for laying the signal transmission medium requires a great deal of labor. In addition, the equipment cost becomes enormous. Said
In the case of (iii), the reference signal is applied to the high-voltage distribution system from one of the signal detection devices, so that the reference signal is not transmitted to the other signal detection device depending on the situation of the fault, Accident point location may not be possible. Further, since the reference signal is detected from the high-voltage distribution system, it is necessary to provide a means for separating the discharge pulse and the reference signal in the signal detection device, and the configuration becomes complicated. Further, the device for generating the reference signal becomes large.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for locating a fault in an electric power system, which can easily and quickly locate the fault.

[0007]

According to the present invention, in order to achieve the above object, signal detection devices are connected to both sides of a section of a power system having an accident point, and time information is provided near each of the signal detection devices. generating a plurality of <br/> time pulse as a measurement reference by receiving radio waves with the detected discharge pulses caused by the discharge pulse current generated in the fault point at the signal detection device, prior to
The discharge pulse is applied to any of the signal detection devices.
A predetermined one of the plurality of time pulses
When detected after the time of occurrence of the
The time elapsed from the time point of occurrence of the time pulse to each discharge pulse detected by each of the signal detection devices after the predetermined one time pulse is measured, and the discharge pulse is measured.
Is the predetermined one in any of the signal detection devices.
If it is detected before the time point of occurrence of one time pulse,
Of a plurality of time pulses before a given time pulse
Each emission detected by each signal detection device from the time of occurrence
Each elapsed time until the electric pulse was measured and measured
A fault location method for a power system, wherein the fault location is determined based on the respective elapsed times.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a measurement system to which an accident point locating method for a power system according to the present invention is applied. 1 is a high voltage distribution line as an electric power system. When an accident occurs in the high-voltage distribution line 1 and the line becomes a blackout line, sensors 2a and 2b are installed on both sides of the accident point 1a. A current transformer or the like is used for the sensors 2a and 2b, and the signal detectors 3a and
3b is connected. Each of the signal detection devices 3a and 3b has a GPS (Global Pos.
tioning System) Receivers 4a and 4b are connected.
The signal detection device 3a includes a detection memory 31a that stores the detection signal S1 from the sensor 2a and the time pulse C1 from the GPS receiver 4a, and an internal oscillator 32a that gives a timing for writing a signal to the detection memory 31a. Similarly, the signal detection device 3b detects the detection signal S from the sensor 2b.
2 and a detection memory 31b for storing a time pulse C2 from the GPS receiver 4b, and an internal oscillator 32b for giving a timing for writing a signal to the detection memory 31b.
In order to locate the accident point on the high voltage distribution line 1,
A power application device 6 that outputs a high DC voltage necessary to cause discharge at the accident point is connected. When setting the orientation,
This DC high voltage causes a discharge at the fault point. However, it is not necessary in the case of orientation on livelines. In a live line, discharge occurs at the accident point due to commercial power.

[0009] GPS is about 21,000km above the earth
Of the 24 satellites orbiting the orbit formed at
This is a system for receiving signals from more than one device and showing the location of a vehicle or ship equipped with a GPS device on a map displayed on a display, or as numerical data such as latitude. In the present invention, the GPS information is used to generate a reference time for obtaining the detection time of the discharge pulse current at the time of locating the fault point.

[0010] a GPS receiver 4a, 4b that receives GPS information from a satellite, process the GPS information received, generates a time pulse C ₁ in GPS receiver 4a, the time in the GPS receiver 4b generating a pulse C _2.
FIG. 2 shows a signal waveform in the fault locating method of the present invention.
The accident point locating method of the present invention will be described below with reference to FIGS.

As shown in FIG. 1, when an accident occurs in the high-voltage distribution line 1, a distance range including a position considered as the accident point 1a is set as a measurement section. Then, the sensor 2a is installed at a point X1 on one side of the accident point 1a, and the sensor 2b is installed at a point X2 on the opposite side. Signal detectors 3a and 3b are connected to the sensors 2a and 2b, respectively.
a and 4b are connected. Next, in order to cause a discharge at the fault point 1a, the power application device 6 is connected to the conductor of the high-voltage distribution line 1 near the signal detection device 3a, and a high DC voltage is applied to the high-voltage distribution line 1. Due to this power application, discharge occurs at the fault point 1a, and a discharge pulse current 7 is generated. The discharge pulse current 7 becomes discharge pulses 7a and 7b, propagates in the high-voltage distribution line 1 in a direction away from the fault point 1a, and is detected by the signal detection devices 3a and 3b, thereby detecting the detection signals S1 and S1.
S2.

By detecting the detection signals S1 and S2, it can be seen that an accident point 1a exists between the signal detection devices 3a and 3b. However, only with this, the time difference between the detection signals S1 and S2 is unknown, so that the position of the accident point 1a cannot be specified. In order to determine the time difference between the detection signals S1 and S2, the signal detection devices 3a and 3b need to have a reference for determining the detection time of the discharge pulses 7a and 7b. Therefore, time pulses C ₁ and C ₂ (C ₁ = C ₂ ) are obtained from the GPS receivers 4a and 4b, and the time difference (t1−t2) is obtained.

As shown in FIG. 2, the GPS receivers 4a, 4
The time t1 between the generation time of the time pulse C12 output from b and the detection time of the discharge pulse 7a is measured by the signal detection device 3a. At the same time, the time t2 of the generation time of the time pulse C22 and the detection time t2 of the discharge pulse 7b are signaled. The measurement is performed by the detection device 3b. As a result, when the times of occurrence of the time pulses C12 and C22 are the same, and the times t1 and t2 are measured starting from this timing, the detection signal time difference between the positions X1 and X2 becomes the difference between t1 and t2. (= T1−t2).

Here, the interval (cycle) T of the time pulse C
Are the detection memories 31a, 31 of the signal detection devices 3a, 3b.
b, the accuracy of the internal oscillators 32a and 32b,
The determination is made in consideration of the time required for the discharge pulses 7a and 7b to propagate through the high-voltage distribution line 1. Specifically, the measurement line length of the high-voltage distribution line 1 is set to be equal to or longer than the propagation time of the discharge pulses 7a and 7b. Since the interval T between the time pulses C is longer than the time required for the discharge pulses 7a and 7b to propagate through the measurement line length of the high-voltage distribution line 1, the time to be determined by the signal detection devices 3a and 3b is uniquely determined.

FIG. 3 shows the relationship between the time pulse C and the discharge pulse current when the time interval T between the time pulses is much shorter than the propagation time of the discharge pulses 7a and 7b. In this case, it is unknown which time pulse the time is measured, and unless specified, an accurate time cannot be obtained. If the time interval T between the time pulses is long, as shown in FIG. 2, if it is determined in advance that the time pulse before the discharge pulses 7a, 7b is used, the time difference (t1) from the same time pulse (C12, C22) is determined. −t2) can be obtained. However, as described above, when the interval T between the time pulses is set to be equal to or longer than the time during which the discharge pulses 7a and 7b propagate through the high-voltage distribution line 1, the time pulses C1 and C2 do not become the same depending on the generation state of the discharge pulse current 7. there is a possibility.

FIG. 4 shows a case where the time pulses C are not the same due to the state of generation of the discharge pulse. In order to avoid such a state, the time measured by the signal detection devices 3a and 3b is not only the time difference from one time pulse, but also
It is effective to measure a time difference with respect to a plurality of time pulses before that. Specifically, as shown in FIG.
When the discharge pulse 7b is before the time pulse C22,
The times t2 and t3 may be obtained based on the time pulse C21. In addition, a time range in which a measurement error is likely to occur is set in advance, and one time of the signal detection devices 3a and 3b is shorter than the set value and the other time is longer than the set value. At this time, it is also effective to set the measured value shorter than the set value to the time between the immediately preceding time pulse and the like. The set value is desirably set so that the measurement line length of the high-voltage distribution line 1 is about the time required for the discharge pulses 7a and 7b to propagate.

Therefore, it is desirable that the time pulse interval is set so that the measurement line length of the high voltage distribution line 1 is several times as long as the propagation time of the discharge pulses 7a and 7b. Time pulse interval T
Is within an interval that can be sufficiently stored in the capacity of the detection memories 31a and 31b, and the internal oscillators 32a and 32b
Is within an allowable interval as an error of the time difference to be measured. When an overhead line of about 10 km is to be measured, it is appropriate to set the interval T between time pulses to several kHz to several tens kHz. However, the duty ratio may be arbitrary.

Next, basic processing for locating an accident point using the time difference calculation result will be described. Discharge pulse 7
Assuming that a discharge pulse current 7 is generated at the center between the signal detection devices 3a and 3b when the signals a and 7b propagate in the high-voltage distribution line 1 at the same propagation speed, the time t1 and the time t2 of the signal detection devices 3a and 3b The difference is zero. That is, the times t1 and t2
Represents a deviation from the center. Therefore, a basic calculation formula for calculating the distance F from the position X1 to the accident point 1a is represented by the following formula.

F = (t1-t2) * K / 2 + L / 2 (where K is the propagation speed, and L is the signal detectors 3a, 3b)
When the high-speed distribution line 1 has a different propagation speed in the middle,
For example, when the overhead insulated line changes from underway to an underground cable or an overhead cable, the fault point may be calculated by compensating the line length based on the propagation speed difference.

Although the method of locating an accident point on an outage line after an accident has been described above, when locating an accident point on a live line according to the present invention, a power application device 6 for generating a discharge is installed. There is no need. In the above embodiment, when the location of the branch line accident is also performed at the same time, it is possible to install the signal detection devices 3a and 3b also at the branch end. Although the high-voltage distribution line 1 has been described as an example of the power system, the present invention is not limited to the high-voltage distribution line, and can be applied to all lines that generate a discharge pulse current at the point of an accident.

The output of an atomic oscillator may be used instead of the GPS receivers 4a and 4b in FIG. In addition, a radio wave having time information such as JST (standard time radio wave) can be used instead of the GPS. The selection is made in consideration of the orientation accuracy and the environment in which the signal detection device is installed.

[0022]

As described above, according to the power system fault point locating method of the present invention, a time pulse is generated based on time information and used as a measurement reference, and a reflected pulse from the fault point in the measurement section is measured. Detected by the signal detection device, each time from the time pulse to the time of occurrence of each of the detected discharge pulses is measured, and the position of the accident point is obtained by the calculated time, so that the accident point can be easily located. In addition, it becomes possible in a short time, and the power failure recovery time can be shortened. Further, a medium such as a communication line for obtaining synchronization between the signal detection devices is not required, so that the equipment can be simplified and the cost can be reduced. In addition, since it is possible to locate on a live line, it is possible to locate an extinct accident.

[Brief description of the drawings]

FIG. 1 is a system diagram showing a measurement system to which an accident point locating method for a power system according to the present invention is applied.

FIG. 2 is a waveform chart showing a signal waveform in the accident point locating method of the present invention.

FIG. 3 is a waveform diagram showing a relationship between a time pulse and a discharge pulse when an interval T between time pulses is extremely shorter than a propagation time of a discharge pulse current.

FIG. 4 is a waveform diagram showing a case where time pulses do not become the same due to a generation state of a discharge pulse current.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 High voltage distribution line 1a Accident point 2a, 2b Sensor 3a, 3b Signal detection device 4a, 4b GPS receiver 6 Power supply device 7 Discharge pulse current 7a, 7b Discharge pulse 31a, 31b Detection memory 32a, 32b Internal oscillator C1, C2 C11, C12, C21, C22 time pulse S1, S2 detection signal

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Koichi Sato 5-1-1, Hidaka-cho, Hitachi City, Ibaraki Prefecture Inside the Power System Research Laboratories Nippon Cable Co., Ltd. (72) Inventor Kazuo Kotani Hidaka, Hitachi City, Ibaraki Prefecture 5-1-1, Machida Electric Power Co., Ltd. Power System Laboratory (72) Inventor Kenichiro Soma 5-1-1, Hidaka-cho, Hitachi City, Ibaraki Pref. Chishin (56) References JP-A-1-242974 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G01R 31/08-31/11

Claims (3)

(57) [Claims] 1. A signal detection device is connected to both sides of a section of a power system having an accident point, and a plurality of time pulses serving as a measurement reference are generated by receiving a radio wave having time information near each of the signal detection devices. And detecting a discharge pulse associated with a discharge pulse current generated at the fault point in each of the signal detection devices, wherein the discharge pulse is generated in any of the signal detection devices.
Is a predetermined one of the plurality of time pulses.
If it is detected after the time of occurrence of the
The respective elapsed time from the generation time point of the time pulse to each discharge pulse detected by each of the signal detection devices is measured, and the discharge pulse is detected by any one of the signal detection devices.
Detected before the point of occurrence of the predetermined one time pulse.
When a plurality of times before the predetermined one time pulse
Is detected by each of the signal detection devices from the time of occurrence of the time pulse
The elapsed time until each of the above-mentioned discharge pulses is measured.
Constant, and the fault point locating method of a power system which determines the location of the fault point on the basis of said measured respective time elapsed. 2. The method according to claim 1, wherein the radio wave is a GPS signal. 3. The time pulse is generated at intervals of several k.
Hz~ Ri tens kHz der accident point locating method of a power system of claim 1, wherein said interval is set to about 10 km.