JP2008191023A - Voltage cable fault detector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a voltage cable fault detector for easily discriminating which direction a fault point exists when being positioned in the vicinity of a branch point of an electric wire. <P>SOLUTION: The voltage cable fault detector includes: a magnetic field sensor 3 for detecting a magnetic field of three orthogonal directions (X, Y, Z); an X-directional component detected with the magnetic field sensor; a Y-directional component; and MPU 7 displaying on an output displaying display 8 unit by calculating an output level based on a Z-directional component at each component. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an electric charging circuit accident survey device, and more specifically, applies a pulse voltage to the electric circuit in the accident section, receives radio waves radiated from the electric circuit on the ground, and determines the accident point. It relates to the improvement of the configuration to be performed.

  As is well known, there is a method (electric charging method) for searching for an accident point on an electric circuit by applying a pulse voltage to the electric circuit in the accident section. Known documents of this method include, for example, Patent Documents 1 to 3. As shown in FIG. 1, the technology disclosed in this publicly known document connects a power application device 50 to an electric circuit 1 in an accident section, applies a DC high voltage pulse, and charges the line 1 in the accident section. The fault point is searched from the state of the current and the discharge current. The receiver 101 having the proximity type current sensor 100 such as a current transformer is brought into contact with the electric circuit 1 to detect the pulse current, and the position of the fault point is detected. Is determined.

  As shown in FIG. 2, for example, Patent Documents 4 to 6 disclose a power-applying device 50. As shown in FIG. 2, a power supply device 51 that generates a high DC voltage, a capacitor C1 for charge storage, a resistor R1 for discharging, and a resistor R2 A waveform shaping circuit 52 in which a capacitor C2 and a capacitor C3 are connected in a π-type, a vacuum switch VS1 for switching discharge, a vacuum switch VS2 for voltage output, a switch control circuit 53, and the like. The pulse voltage is output by accumulating and discharging it in response to switching.

  That is, the power application device 50 outputs a pulse voltage at a predetermined cycle, and the power supply device 51 inputs a commercial power supply or the like to convert it into a DC high voltage of, for example, 15 kV, and charges the capacitor C1. The charge energy accumulated in the capacitor C1 is discharged to the electric circuit 1 side by the vacuum switch VS2 through the waveform shaping circuit 52. For example, the electric charge that is forcibly grounded by the vacuum switch VS1 after 10 msec and charged in the electric circuit 1 is discharged through the resistor R1. To do. This series of operations is repeated, for example, every 4 seconds. As a result, a rectangular pulse having a pulse width of 10 msec, a repetition period of 4 sec, and a peak value of 15 kV is output as shown in FIG.

  However, in this method, the proximity type current sensor 100 is hooked on the electric path 1 for detection measurement, so that an ascending work for an operator to climb up the electric pole is required, or an operation with a bucket car is required. For this reason, it takes a lot of labor and time to detect the accident point, and workers are required on the electric circuit 1 and the ground, respectively, and workability is poor.

  Therefore, for example, as can be seen in Patent Documents 7 to 12 and the like, there is a proposal of a technique capable of searching for an accident point on the ground. In this technique, the pulse current flowing in the electric circuit is received by a receiver equipped with an antenna, and the accident point is searched by performing a predetermined discrimination process on the received signal.

JP-A-57-3056 JP-A-57-3057 JP 59-24272 A JP-A-48-50238 JP 54-140929 A JP 54-140931 A JP-A-55-134365 JP-A-56-3516 JP-A-57-179964 JP 58-5676 A JP-A 63-243769 Japanese Unexamined Patent Publication No. 63-243771

  However, the apparatus configuration that searches for an accident point on the ground by such antenna reception has the following problems. In the techniques described in Patent Documents 7 to 12 and the like described above, the logic of the discrimination process is based on the idea that the detection signal is processed in a single timing, and can be discriminated theoretically for a unit pulse. Although it seems, ideal operation cannot be expected in the field environment where the noise level is high, and there is a doubt in practicality.

  Furthermore, in the conventional apparatus configuration for searching for an accident point on the ground, it is difficult to distinguish between the accident side and the non-accident side near the branch point of the distribution line.

  The present invention solves the above-described problems, and the purpose of the invention is to investigate the point of the accident on the ground and determine in which direction the point of the accident is when located near the branch point of the distribution line. It is an object of the present invention to provide an electric charging type electric circuit accident investigation device that can be easily identified.

  In order to achieve the above-mentioned object, the electric charging type electric line accident investigation device according to the present invention is an electric charging type electric line accident investigation method in which a pulse voltage is applied to the electric circuit in the accident section by the electric application device to investigate the accident point. A device that detects magnetic fields in three orthogonal directions (X, Y, Z), an X direction component detected by the magnetic field sensor, a Y direction component, and an output level based on the Z direction component. Display means for outputting and displaying each.

  Storage means for storing and holding the output level for a certain period may be provided, and the display means may display past data stored in the storage means together. Furthermore, it is preferable to provide a function for displaying the output level obtained by vector synthesis in the three directions on the display means.

  In the present invention, by detecting the magnetic field generated with the applied current, the fault point can be searched on the ground, and the fault point is located in any direction when it is located near the branch point of the distribution line. Can be easily identified.

  FIG. 4 shows a preferred embodiment of the present invention. In this embodiment, the electric power distribution type electric line accident investigation device 2 has a magnetic field sensor 3 for detecting a magnetic field, and is caused by the electric current flowing through the distribution line by applying electric power to the electric circuit 1 in the accident section by the electric power application device 50. The magnetic field f generated in this manner is detected on the ground using the magnetic field sensor 3, and the accident point is determined based on the detection result. The voltage applying device 50 has the configuration shown in FIG. 2 described above, and outputs a rectangular pulse having a pulse width of 10 msec, a repetition period of 4 sec, and a peak value of 15 kV as shown in FIG.

  FIG. 5 shows a block diagram of the charging-type circuit fault investigation device 2 of the present embodiment. In this electric charging type circuit fault investigation device 2, three uniaxial magnetic field sensors 3 a, 3 b, 3 c are prepared as magnetic field sensors 3 and arranged so as to be orthogonal to each other. As a result, the magnetic field sensors 3a, 3b, and 3c can detect magnetic fields in the three-axis directions of the XYZ orthogonal coordinate system. Hereinafter, when the three single-axis magnetic field sensors are described separately, they are referred to as an X-axis magnetic field sensor 3a, a Y-axis magnetic field sensor 3b, and a Z-axis magnetic field sensor 3c. In the present embodiment, each uniaxial magnetic field sensor 3a, 3b, 3c is formed using a solenoid or a pickup coil.

  The outputs of the uniaxial magnetic field sensors 3a, 3b and 3c are connected to a series circuit of a band pass filter 4 and an amplifier 5, respectively, and the output of each amplifier 5 is provided to the MPU 7 via the A / D converter 6. To do. As a result, magnetic field detection is provided in three systems, so that magnetic field detection can be performed separately in the three directions of the X-axis direction, the Y-axis direction, and the Z-axis direction. Can be obtained individually or as an arbitrary 2-axis or 3-axis composite value (vector synthesis) and output and displayed on the display unit 8.

  FIG. 6 shows distribution line transmission characteristics of the applied pulse. From this characteristic, since the measurement frequency is optimally 1 kHz to 100 kHz, the bandpass filter 4 is set so as to pass through the frequency band.

  FIG. 7 shows a magnetic field differential waveform by an applied voltage pulse when a ground fault has occurred. When a ground fault has occurred, as shown in FIG. 4, a ground fault current flows through the electric circuit (distribution line) 1, and accordingly, a magnetic field is generated around the electric circuit 1. Since the ground fault current flows when the applied pulse is ON, the magnetic field accompanying the ground fault current is also generated intermittently (once every 4 seconds). The measured values detected and output by the uniaxial magnetic field sensors 3a, 3b, and 3c are the differential values of the magnetic field generated by the applied current, and therefore should be integrated accurately. In the embodiment, since it is only necessary to detect the presence or absence of current, the configuration of the apparatus is simplified without performing integration processing. Of course, an integration circuit may be mounted.

  In addition, since the power application pulse is turned on once every 4 seconds and the time of 4 seconds of one cycle varies, a reference level is set in order to reliably detect the applied current and the magnetic field generated by the ON. The MPU 7 judges that a magnetic field accompanying the applied current is generated when a signal exceeding the reference level is input, and records data from data slightly before the input of the signal. .

  The MPU 7 performs predetermined processing on the input data (signal processing (frequency filtering & amplification & AD conversion) for the output of the magnetic field sensor) to display data under the conditions specified by the user, and the display unit 8 To display. Here, the instruction from the user is which display function is used to display the magnetic field in the axial direction of XYZ or the combined magnetic field. This instruction is given by pressing an input switch for giving each instruction if the electric charging type electric circuit accident investigation device 2 is a dedicated device, and the electric application type electric circuit accident investigation device 2 uses a general-purpose computer. When configured, it is given by operating a keyboard or other input device.

  The display functions prepared in this embodiment include an oscilloscope function and a bar graph function. The former oscilloscope function, like a digital oscilloscope, provides a level trigger function that sweeps when a signal exceeding a predetermined reference level is input, and displays the waveform from a time slightly before the trigger detection. To do.

  The latter bar graph function displays the level detected by the trigger (above the reference level) a plurality of times in time series. In this embodiment, as shown in FIG. 8A, the measurement level of the magnetic field near the power application point (a point 20 m away from the power application device 50) is always displayed at the left end of the display area (see FIG. 8A). (Indicated by middle hatching), the display mode displays the trigger detected level while moving to the left, and the relative level calculated based on the trigger detection is displayed while moving to the left as shown in FIG. A display form. Here, the relative level first obtains the reference measurement level of the magnetic field near the charging point (a point 20 m away from the charging device 50), and divides the level detected by each trigger by the reference measurement level. Ask for it. If the trigger is not detected even after a predetermined time (4 seconds + α) has elapsed since the previous trigger detection, the level (relative level) is set to 0 and the next level detection is prepared, assuming that no magnetic field is detected.

  This device has a storage unit for storing a reference measurement level to realize the above display function, a value input from each of the three systems of the uniaxial sensors 3a, 3b, and 3c, and / or a value obtained by vector combining them. And MPU 7 stores predetermined data in these storage units. The storage unit may be included in the MPU 7. Further, the data to be stored and held is the level detected by the trigger. If a signal exceeding the reference level is not received even after a predetermined time (4 seconds + α) has elapsed, the level of the data to be stored and held is “0”. ".

  Next, the operation principle for recognizing the direction of the accident point by the electric charging type electric circuit accident investigation device 2 of the present embodiment will be described. In a simple T-shaped branch line (point A: branch point) as shown in FIG. 9, a ground fault occurs at point B (see FIG. 9 (a)) and a point C occurs ( For each of the magnetic field distributions, see FIG. Here, a branch point (point A) exists on the wire L1, and the wire L2 connecting the point A and the point B is orthogonal to the wire L1.

  As shown in FIG. 9 (a), when a ground fault occurs at point B, the mirror image of the electric wire L2 is shorted at point B and becomes an open end at point C. In this state, when a voltage application pulse is applied to an arbitrary part of the electric wire L1 upstream from the branch point (A point), the electric current flows from the electric power application device A point to the B point, and the electric wires L1 and L2 Magnetic field is generated around. The magnetic field Ht at an arbitrary coordinate (point P) at this time is the magnetic field created by the electric wire L1 and its mirror image is H1, the magnetic field created by the electric wire L2 and its mirror image is H2, and the ground fault current (from the electric wire at the accident point toward the ground) When the magnetic field generated by the flowing current is H3, the resultant force (vector synthesis) of the magnetic fields H1, H2, and H3 is obtained (see FIG. 9A).

Then, the spatial distribution of each direction component and the magnetic field obtained by combining the three-axis vectors is as shown in FIG. This spatial distribution takes into account that the worker carries out the inspection with the electric circuit accident investigation device 2, and the vertical distance from the electric wire to the electric circuit accident investigation device 2 is 8 m (the electric wire distance from the ground is 10 m). -The ground height was 2 m), and was calculated according to Bi-Ossaber's law, which is a calculation formula for a finite length magnetic field line.

Further, the three-axis vector synthesis Ht of the magnetic field is obtained by the following equation.

  Similarly, when a ground fault occurs at point C, the magnetic field distribution at an arbitrary coordinate (point P) is as shown in FIG. 9B, and the spatial distribution of each direction component and composite component is shown in FIG. It becomes like this.

  As is clear from FIGS. 10 and 11, the magnetic field generated based on the applied current is measured separately for each component of the X, Y, and Z axes, and output to easily identify the location where the ground fault occurred. can do. For example, when moving along an electric wire, even if it moves in the wrong direction (non-accident point side), it can be understood that the magnetic field component level in the X-axis direction becomes 0 if it proceeds at least about 10 m, and even before that If it can be recognized that the level of the magnetic field component in the X-axis direction is gradually decreasing, it can be understood that there is a high possibility of being wrong.

  Further, as apparent from FIGS. 10 and 11 (a) and 11 (b) showing the spatial distribution state of the magnetic field of the X-axis direction component and the Y-axis direction component, the branch point is observed by observing only the direction perpendicular to the electric wire. It is possible to identify in which direction the ground fault has occurred when the point (A) is reached. Furthermore, since the component in the direction perpendicular to the electric wire increases sharply in the immediate vicinity of the ground fault point, the ground fault point can be easily identified from such information.

  As is apparent from FIG. 10 and FIG. 11C showing the spatial distribution state of the magnetic field of the Z-axis direction component, the polarity of the magnetic field changes on the left and right with respect to the direction perpendicular to the electric wire. Therefore, for example, when a plurality of electric wires are parallel to each other, a short-circuit accident occurs on which side of the electric wire by placing the electric charging type electric circuit accident survey device 2 between the plurality of electric wires. Can be easily recognized (the electric wire through which the charging current flows can be identified). Moreover, the path to the accident point can be traced by measuring only the polarity on one side. In this case, the final accident point is specified by measuring the X-axis component or the Y-axis component.

  As shown in FIGS. 10 and 11 (d), the three-axis vector synthesis Ht of the magnetic field also shows a different spatial distribution depending on the position of the accident point. The accident point can be identified.

  Furthermore, accidents that can be detected in the present embodiment are not only complete ground faults, but also in discharge ground faults and resistive ground faults, the applied current is only on the path from the applied point to the accident point. Since it does not flow, the route to the accident point and the accident point can be specified by the various methods described above.

  Next, an accident point search method (operation principle) in this embodiment will be described based on a specific example. As shown in FIG. 12 to FIG. 15, when searching in an area where distribution lines are laid along a road network in which two crossing intersections are provided in a linear direction, the following is performed. First, as shown in the figure, there are two branch points of the distribution line, A1 and A2, and the power-applying device and the accident point are present at the illustrated positions, respectively. In this case, the result measured at each point Pn is displayed on the display unit.

  First, FIG. 12 shows the results for the X direction component. With the application of the power application pulse, the current flows from the power application device toward the accident point, and a magnetic field is generated around the distribution line through which the current flows. Therefore, when the worker moves along the distribution line from the power application point to which the power application device is connected, the output in P1 and P2 has a constant X-axis direction component that is the traveling direction (coincident with the direction in which the applied current flows). It is a level. Then, at the first branch point A1, turn left or right and proceed along the distribution line as it is, and at points P3 and P4, no current flows through the adjacent distribution lines. The component has an output level of zero. Accordingly, the worker knows that the vehicle has traveled in the wrong direction, returns to the first branch point A1, and proceeds straight in the direction of extension of the original road.

  Then, as shown at a point P5, a certain output level appears, so it can be confirmed that the vehicle has traveled in this direction. Further, the output level of the X-axis direction component is gradually reduced. This suggests that there is no accident point in the extension direction of the current traveling direction, and it is necessary to turn in either direction at a branch point on the way. That is, the extension direction in the linear direction is an open end further than the branch point (A2 in the figure) existing in the extension direction, and the current does not flow, so the level of the X-axis direction component becomes small. Then, at the point P6 that actually exceeds the second branch point A2, the output level becomes zero.

  In addition, when the vehicle turns left at the second branch point A2 (when it proceeds to the non-accident point side), it proceeds in the opposite direction to the accident point, so the output level is reversed. Furthermore, if it proceeds as it is, it gradually moves away from the accident point, so its output level gradually decreases. Accordingly, it can be understood that the vehicle is traveling in the wrong direction (turned to the opposite side), and the vehicle can return to the second branch point A2 and travel in the correct direction.

  Conversely, when a right turn is made at the second branch point A2 (when proceeding to the accident point side), an output level above a certain level is displayed (see P8 and P9). And when it becomes close to an accident point like the point P9, the output level also becomes large gradually. Thereby, it turns out that it is approaching the accident point. Although not shown in the drawing, if the accident point is excessively exceeded, the output level is lowered, so that the accident point can be specified.

  FIG. 13 shows the results for the Y direction component. With the application of the power application pulse, the current flows from the power application device toward the accident point, and a magnetic field is generated around the distribution line through which the current flows. Therefore, when the worker moves along the distribution line from the power application point to which the power application device is connected, the output level of the Y-axis direction component, which is the direction orthogonal to the direction in which the current is flowing, is at points P1 and P2. 0. Moreover, when it stops at the point P10 in the middle and turns sideways (in the case of illustration, a distribution line is made back), the output level of the Y-axis direction component becomes a certain level or more.

  Further, when the vehicle turns left or right at the first branch point A1, the output level of the Y-axis direction component appears on the same principle as the display at the point P10. However, in the case of the point P10, since it stopped at the same place, the output level was maintained at almost the same value. However, in the case of the points P3 and P4, since the power distribution current is gradually separated from the distribution line, The output level gradually decreases.

  On the other hand, at the point P5, the magnetic field based on the applied current flowing from the second branch point A2 toward the accident point is detected, and the output level of the Y direction component gradually increases as the point approaches the second branch point A2. When the vehicle travels straight through the second branch point A2, the output level of the Y-direction component gradually decreases from the accident point as indicated by the point P6. Therefore, in this case, the worker can understand that he / she is moving in the wrong direction, returns to the second branch point A2, turns in either direction, and continues the inspection.

  In addition, when reaching the second branch point A2 from the point P5 and making a left turn there, the output level gradually decreases as shown at the point P7, so that the worker is also moving in the wrong direction. Therefore, the operator returns to the second branch point A2 and proceeds in another direction to search for the accident point.

  In addition, when reaching the second branch point A2 from the point P5 and making a right turn at that point, as shown at the point P8, it is initially affected by the magnetic field due to the applied current flowing upstream from the second branch point A2. Although the output level reaches a certain level, when it moves to a certain point and reaches the point P9, the output level of the Y-direction component decreases as with P1 and the like. As is apparent from the display states of P6, P7, and P8 that are downstream of the second branch point A2, whether the vehicle is moving toward the accident point from the history of the output level of the Y-direction component, or a non-accident point It is possible to easily identify whether the vehicle is moving toward

  FIG. 14 shows the results for the Z direction component. With the application of the power application pulse, the current flows from the power application device toward the accident point, and a magnetic field is generated around the distribution line through which the current flows. And since the magnetic field which generate | occur | produces in the circumferential direction centering on a distribution line, the direction of a magnetic field differs in the left side and right side of a distribution line. Therefore, when the worker moves along the distribution line from the power application point to which the power application apparatus is connected, the absolute values of the output levels of the Z direction components are substantially equal at the points P1 and P2 and the points P1 ′ and P2 ′. However, the polarity is reversed. Therefore, by looking at the polarity of the output level of the Z direction component, it can be seen whether the applied current is flowing through the distribution line on the left or right side of the worker.

  Since the charging current flows from the charging device → the first branch point A1 → the second branch point A2 → the accident point, when moving along the path, the absolute value of the output level of the Z direction component is It continues to output a substantially constant value (see P1, P2, P1 ', P2', P5 and P8). On the contrary, when moving along the distribution line away from the route, the output level of the Z direction component gradually decreases (see P3, P4, P6, P7).

  At the accident point, since an applied current flows from the distribution line toward the ground and a magnetic field is generated based on the Z direction, the output level of the Z direction component decreases as the accident point is approached (P9, P9 '). reference). Thus, the accident point can be reached also based on the output level of the Z direction component.

  FIG. 15 shows the results for the XYZ three-axis combined vector. As is apparent from the figure, the output level is higher than a certain level when moving along the distribution line through which the applied current flows. However, as shown in the figure, when the accident point exists in a different direction from the extension direction of the distribution line through which the charging current flows (turns to the right at the second branch point A2), for example, the branch point P5 As the point (A2) is approached, the output level gradually decreases because of the influence of the magnetic field accompanying the applied current from the branch point toward the accident point. Moreover, when it moves along the distribution line which leaves | separates from the path | route through which an applied current flows, the output level of a synthetic | combination vector becomes small gradually (refer P3, P4, P6, P7).

  In order to observe a low level signal close to the thermal noise level and improve the dynamic range, a log amplifier may be connected after the amplifier. However, since the log amplifier can be used only at the positive electrode, a half-wave or full-wave rectifier circuit or a detector circuit is provided in the previous stage.

  Furthermore, the applied pulse signal has a period of about 4 seconds, a pulse width of about 10 msec, a rising time of several tens of microseconds, and has a very long period compared to a high-speed rising edge. Therefore, if a peak hold circuit is connected to the front stage of the AD converter, a pulse can be reliably detected. At this time, if the frequency characteristic of the peak hold circuit is set to several 100 kHz and the hold time is set to several tens of msec, the peak of the applied pulse can be easily made even if the sampling period is several msec to several tens of msec, which is slower than the rising of the applied pulse. Can be caught.

It is a figure which shows an example of the past and explains the outline of the accident point search in the electric circuit. It is a circuit diagram which shows the basic composition of an electric power generation apparatus. It is a graph which shows the waveform of the pulse voltage to apply. It is a block diagram which shows the example which concerns on this invention and demonstrates the outline | summary of the accident point search in an electric circuit. 1 shows a preferred embodiment of a power transmission type circuit fault survey device according to the present invention. It is a graph which shows the frequency characteristic (P-Spice calculation value) of a distribution line. It is a graph which shows the magnetic field differential waveform by an applied pulse. It is a figure which shows an example of a display form. It is a figure explaining an operation principle. It is a figure explaining an operation principle. It is a figure explaining an operation principle. It is a figure which shows the result about a X direction component. It is a figure which shows the result about a Y direction component. It is a figure which shows the result about a Z direction component. It is a figure which shows the result of vector composition.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Electric circuit 2 Electric charging type electric circuit accident investigation apparatus 3 Magnetic field sensor 3a X-axis magnetic field sensor 3b Y-axis magnetic field sensor 3c Z-axis magnetic field sensor 4 Band pass filter 5 Amplifier 6 A / D converter 7 MPU
8 Display 50 Electric power application device f Magnetic field

Claims (3)

It is a charging-type electric circuit accident exploration device for exploring the accident point by applying a pulse voltage to the electric circuit in the accident section by means of an electric charging device,
A magnetic field sensor for detecting magnetic fields in three orthogonal directions (X, Y, Z);
Display means for outputting and displaying the output level based on the X direction component, the Y direction component, and the Z direction component detected by the magnetic field sensor;
The electric charging type electric circuit accident investigation device characterized by comprising. Storage means for storing and holding the output level for a predetermined period;
The pasting data stored in the storage means is displayed together with the display means.   2. The electric power application according to claim 1, further comprising a function of displaying on the display unit an output level obtained by vector synthesis of the three directions or an output level obtained by vector synthesis of an arbitrary two of the three directions. Type electric circuit accident investigation device.

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