JP5127736B2 - Accident location detection system and accident section identification method - Google Patents

Description

  The present invention relates to an accident location detection system that detects the location of an accident that has occurred on a power line, and an accident section identification method that uses the accident location detection system.

  There are various methods for locating the failure point of a transmission line, but it is necessary to attach various sensors near the power line or an overhead ground line in order to separate the signal indicating failure and unnecessary noise. there were. The background will be described below.

  FIG. 6 is a diagram illustrating the influence on the steel tower when a fault surge current flows through the power line. Fig.6 (a) shows the top view of a steel tower. The power line EW and the overhead ground line GW have different heights, but are installed substantially parallel between the steel towers. When a ground fault occurs at one location of the power line EW, a fault surge current flows toward the fault location (failure point). And the induction surge current flows into the overhead ground wire GW by the electromagnetic induction resulting from the failure surge current. The direction of this induced surge current is opposite to the direction of the fault surge current.

  If there is a difference in electromagnetic coupling between the power line EW and the overhead ground wire GW between the left side and the right side of the steel tower in FIG. 6 (a) due to the difference in the span length of the steel tower, the left side and the right side of the overhead ground wire GW A difference occurs in the magnitude of the induced surge current flowing through the tower, and the difference current flows through the steel tower.

  FIG.6 (b) shows the side view (A arrow directional view of Fig.6 (a)) of some steel towers. The magnetic flux created by the fault surge current flowing through the power line EW is linked to the loop-shaped portion of the tower member, and an induced surge current flows through the tower legs. See Patent Document 1 for details.

  FIG.6 (c) shows the side view (B arrow view of Fig.6 (a)) of the whole steel tower. In order to determine the location (section) where the ground fault occurs, it is necessary to detect the direction of the magnetic field generated by the fault surge current flowing through the power line EW. However, near the ground, the magnetic field intensity due to the fault surge current is weak, and the influence of the induced surge current flowing through the tower base cannot be ignored, so it is difficult to detect the direction of the magnetic field due to the fault surge current.

  As described above, the conventional detector is placed not near the ground but near the power line.

JP 2008-39549 A Japanese Patent No. 3226554

  According to the above-described conventional configuration, it is necessary to perform work at a high place where the detector is located or dangerous work such as approaching the power line being charged, which increases the cost of detector installation and maintenance. There is. Therefore, there is a demand for a method capable of separating a signal indicating a failure from unnecessary noise even at the bottom of the steel tower.

  Patent Document 2 discloses a method for locating an accident occurrence section by installing a plurality of sensors for detecting a magnetic field formed by a power transmission line in the vicinity of a lower part of a steel tower. Current is not considered.

  The present invention has been made in view of the above problems, and its main purpose is to separate a signal indicating a power line failure and unnecessary noise near the ground.

  In order to solve the above-mentioned problem, the present invention is an accident location detection system for detecting the location of an accident that has occurred in a power line installed on a steel tower, wherein the fault flows through the power line near the ground in the steel tower. A first surge magnetic field is installed perpendicular to both the direction of the surge current and the direction of the induced surge current flowing through the tower pedestal, and detects a first surge magnetic field that is a magnetic field due to the fault surge current and the induced surge current. And a second surge that is a magnetic field generated by the induced surge current and is installed near the ground, parallel to the direction of the fault surge current and perpendicular to the direction of the induced surge current. Difference between the second coil for detecting a magnetic field, the first surge magnetic field detected by the first coil, and the second surge magnetic field detected by the second coil Based on, characterized in that it comprises a current direction determination section determines the direction of the fault surge currents.

  According to this configuration, since the first coil is installed perpendicular to the direction of the fault surge current flowing through the power line and the direction of the induced surge current flowing through the tower base, the magnetic field due to the fault surge current and the magnetic field due to the induced surge current are generated. Both are detected. On the other hand, since the second coil is installed in parallel to the direction of the fault surge current and perpendicular to the direction of the induced surge current, the magnetic field caused by the fault surge current is not detected, and the magnetic field caused by the tower base induced surge current is detected. Is detected. Therefore, by taking the difference between the surge magnetic field detected by the first coil and the surge magnetic field detected by the second coil, the direction of the magnetic field due to the fault surge current in the power line can be known, and consequently the direction of the fault surge current. Can be determined. According to this, it is possible to separate a signal indicating a power line failure (failure surge current) and unnecessary noise (inductive surge current) near the ground.

  Moreover, this invention is an accident location detection system, Comprising: The said electric current direction determination part outputs the voltage which the said 1st coil outputs with a change of the said 1st surge magnetic field, and the said 2nd coil is the said It is characterized in that a difference from a voltage output in accordance with a change in the second surge magnetic field is taken, and the direction of the fault surge current is determined according to the sign of the difference.

  The present invention is also an accident location detection system, wherein the tower is near the ground, parallel to the direction of the fault surge current and perpendicular to the direction of the commercial frequency current flowing through the tower legs. A third coil that detects a commercial frequency magnetic field that is a magnetic field generated by the commercial frequency current and outputs a first voltage; and A / D converts the first voltage output from the third coil. When the state where the effective value of the A / D converter that outputs the second voltage and the second voltage output from the A / D converter is equal to or greater than a predetermined value continues for a predetermined time or longer, And a self-tower accident determination unit that determines that an accident has occurred in the steel tower in which the third coil is installed.

  According to this configuration, the third coil is installed near the ground in parallel to the direction of the fault surge current flowing through the power line and perpendicular to the direction of the commercial frequency current flowing through the tower base. The magnetic field by can be detected. According to this, it can be known that an accident has occurred in the steel tower in which the third coil is installed.

  Further, the present invention is an accident location detection system, wherein the first coil and the second coil are installed on a concentric circle centered on the axis of the tower base, and have the same electromagnetic induction characteristics It is characterized by having.

  According to this configuration, since the two coils are located at the same distance from the tower base axis and have the same electromagnetic induction characteristics, the conditions except for the installation direction are the same, and the magnetic field due to the induced surge current flowing through the tower base is the same. Are detected equally. According to this, it is possible to accurately specify the fault surge current flowing through the power line, and to accurately determine the direction thereof.

  Further, the present invention provides an accident section identification method for identifying an accident section in the power line using the accident location detection system, wherein each of a plurality of the towers connected to each other is near the ground. A step of installing the first coil and the second coil, a step of acquiring the direction of the fault surge current determined by the current direction determination unit for each tower when an accident occurs in the power line, When the direction of the fault surge current determined by the current direction determination unit relating to the two towers is reversed, the step of identifying the section between the two towers as an accident section is performed.

  According to this method, because the accident section is identified using a coil installed near the ground in the steel tower, dangerous high-altitude work is eliminated, and installation work costs and maintenance costs for the accident location detection system are reduced. Is possible.

  In addition, the problems disclosed by the present application and the solutions thereof will be clarified by the description of the mode for carrying out the invention and the drawings.

  According to the present invention, a signal indicating a power line failure and unnecessary noise can be separated near the ground. According to this, it is possible to install a coil for detecting a signal indicating a power line failure near the ground, and there is no dangerous work in high places, so it is possible to reduce the installation cost and maintenance cost of the accident location detection system become.

It is a figure explaining the principle of the method of locating an accident area. It is a figure explaining the principle of the method of detecting a ground fault other than the own tower, (a) shows a front view of the tower, (b) and (c) show a top view of the tower, (c) In particular, the method of attaching the coil when the power line has a horizontal angle is shown. It is a figure explaining the principle of the method of detecting the ground fault accident of the own steel tower, (a) shows the front view of a steel tower, (b) shows the top view of a steel tower. 1 is a diagram illustrating a configuration of a detection system 1. FIG. 3 is a flowchart showing processing of the detection system 1. It is a figure which shows the influence on a steel tower when a fault surge current flows through a power line, (a) shows the top view of a steel tower, (b) shows the side view of a part of steel tower, (c) is the whole steel tower The side view of is shown.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. The detection system (accident location detection system) according to the embodiment of the present invention is configured so that, for accidents other than the own tower, both directions of the fault surge current flowing through the power line and the induced surge current flowing through the tower base are near the ground. And a second coil having an axial direction parallel to the direction of the fault surge current and perpendicular to the direction of the induced surge current (the second coil is a column base) A current transformer that detects only the current) is installed, and the magnetic field created by the induced surge current is determined based on the difference between the surge magnetic field detected by the first coil and the surge magnetic field detected by the second coil. The direction of the magnetic field generated by the failure surge current is canceled (and the direction of the failure surge current is detected).

  On the other hand, for the determination of the ground fault of the own tower, the commercial frequency magnetic field is detected near the ground, with the axis direction parallel to the direction of the fault surge current and perpendicular to the direction of the commercial frequency magnetic field flowing through the tower base. A third coil to be installed is further installed, and the magnetic field generated by the commercial frequency current of the accident tower base detected by the third coil is used.

  According to this, by arranging a detection system on each of a plurality of consecutive steel towers, when two detection systems are arranged across an accident point, the direction of the magnetic field detected by the two detection systems Since the situation is reversed, the accident section can be located. In addition, high reliability can be obtained when identifying a ground fault.

  FIG. 1 is a diagram for explaining the principle of a method for locating an accident section. As shown in FIG. 1, a detection system 1 for detecting the direction of a magnetic field (further, the direction of current) is installed at the lower part (near the ground) of a plurality of towers, and the magnetic fields detected by the plurality of detection systems 1 are detected. Of the directions (and the current direction), the section where the direction is reversed is determined as the accident section.

  Specifically, when a ground fault occurs at an accident point on the power line EW shown in the center of the figure, a fault surge current flows toward the accident point. As a result, the detection systems 1a, 1b, and 1c installed on the steel tower on the left side of the accident point in the figure detect that the fault surge current flows in the right direction. On the other hand, the detection systems 1d, 1e, and 1f installed on the steel tower on the right side of the accident point in the figure detect that a fault surge current flows in the left direction. Therefore, when the current directions detected by the detection systems 1a to 1f are viewed in order, it is understood that the current direction is reversed between the detection systems 1c and 1d. Thereby, it can be determined that a ground fault has occurred in the section between the detection systems 1c and 1d. For the orientation of the accident section, a computer system that can communicate with each detection system 1 may be used, or a person may grasp and judge the output information (current direction) of each detection system 1.

  FIG. 2 is a diagram for explaining the principle of a method of detecting a ground fault other than the own tower, FIG. 2 (a) shows a front view of the steel tower, and FIG. 2 (b) shows a top view of the steel tower. FIG.2 (c) shows the top view of a steel tower, and shows the attachment method of a coil especially when a power line has a horizontal angle.

  When a ground fault occurs in the power line EW, the direction of the fault surge current propagating in the vicinity of two adjacent towers across the fault point in the power line EW is different. By detecting the direction of the magnetic field to be created, the tower section where the direction of the magnetic field is reversed can be specified as the accident section (failure section). However, the difference of the induced surge current flowing through the overhead ground wire GW and the induced surge current induced in the loop of the steel tower member flow to the steel tower leg, and create a magnetic field around the steel tower leg. That is, since a magnetic field due to a fault surge current and a magnetic field due to an induced surge current are created around the tower pedestal, it is necessary to detect only the fault surge current. The induced surge current flowing through the overhead ground wire GW also creates a magnetic field, but the influence is small because the overhead ground wire GW is farther from the power line EW from the lower part of the tower.

  Therefore, as shown in FIG. 2, the coils C1 and C2 of the detection system 1 are installed in the lower part of the steel tower, that is, near the ground. In this case, the coil C1 and the coil C2 are at the same height (concentric circles centered on the axis of the tower pedestal, but are not allowed to be misaligned within a range in which changes in the magnetic field due to the current flowing through the tower pedestal are equally detected. The characteristics (for example, the number of turns of the coil) related to electromagnetic induction are the same, and a surge magnetic field that is a magnetic field due to a surge current is detected.

The coil C1 is installed such that its axial direction is perpendicular to the direction of the fault surge current flowing through the power line EW and the direction of the induced surge current flowing through the tower base. As a result, the coil C1 is linked to the magnetic flux generated by the fault surge current propagating through the power line EW and also linked to the magnetic flux generated by the induced surge current flowing in the tower base. Both magnetic fields due to current are detected. On the other hand, the coil C2 is installed such that its axial direction is parallel to the direction of the fault surge current and perpendicular to the direction of the induced surge current. As a result, the coil C2 is not linked to the magnetic flux generated by the fault surge current, and is linked to the magnetic flux generated by the induced surge current, so that only the magnetic field due to the induced surge current is detected. Then, the detection system 1 takes the difference between the magnetic field detected by the coil C1 and the magnetic field detected by the coil C2, thereby removing the influence of the induced surge current flowing through the tower base, and by the failure surge current flowing through the power line EW. The direction of the magnetic field (and hence the direction of the fault surge current) is determined.
Although the coil C3 is illustrated, it is not used in principle.

  FIG. 3 is a diagram for explaining the principle of a method for detecting a ground fault in the own tower, in which FIG. 3 (a) shows a front view of the tower and FIG. 3 (b) shows a top view of the tower.

  Since the fault surge current flowing through the power line EW flows toward the accident point, the magnetic field distribution immediately below the fault point becomes a complex aspect, and it is considered that the magnetic field generated by the fault surge current cannot be detected well. For this reason, the determination of the direction of the magnetic field due to the fault surge current cannot be used to identify the accident point. Therefore, although the coil C1 is illustrated, it is not used in principle. When a ground fault occurs in the steel tower, the fault current that has flowed into the point of the accident is shunted to the overhead ground wire GW side and the ground side, together with the surge component and the commercial frequency component.

  Therefore, as shown in FIG. 3, the detection system 1 includes coils C2 and C3 having different frequency bands to be detected. The coils C2 and C3 are installed so that the axial direction thereof is parallel to the direction of the fault surge current flowing through the power line EW and perpendicular to the direction of the current flowing through the tower base. And coil C2 captures only the surge magnetic field which a surge current makes among fault currents which flow through a tower. On the other hand, the coil C3 captures only the commercial frequency magnetic field generated by the commercial frequency current among the fault currents flowing through the tower legs. In the detection system 1, an AND of the output of the coil C2 and the output of the coil C3 is taken and it is determined that the accident of the own tower. Specifically, in order to suppress standby power, the output voltage of the coil C3 is A / D (Analog / Digital) converted by using the output of the coil C2 to be a predetermined value or more as a trigger, and the digitized output is effective. Determine the validity of the value and duration.

  FIG. 4 is a diagram illustrating a configuration of the detection system 1. The detection system 1 includes coils C1, C2, C3, a threshold storage unit 11, a voltage determination unit 12, an A / D conversion unit 13, an effective value duration measurement unit 14, an own tower accident determination unit 15, a current direction determination unit 16, and A determination result output unit 17 is provided.

  The coil C1 detects a magnetic field component (1 kHz or more) due to a fault surge current of the power line EW and a surge magnetic field component (1 kHz or more) due to a tower leg current. The coil C2 detects only a surge magnetic field component (1 kHz or more) due to the tower base current. The coil C3 detects a commercial magnetic field component (50 Hz or 60 Hz) due to the tower base current.

  The threshold storage unit 11 is a part that stores thresholds used in the detection system 1 (threshold values of magnetic field components output by the coils C1 and C2, and threshold values of magnetic field components output by the coil C3). This is realized by a non-volatile storage device such as a hard disk device. The voltage determination unit 12 determines whether or not the voltage of the magnetic field component output from the coils C1 and C2 and passed through the HPF (High Pass Filter) is greater than a threshold value. If only the voltage of the magnetic field component of the coil C2 is greater than the threshold value, the A / D converter 13 is instructed to start processing. If the voltages of the magnetic field components of the coils C1 and C2 are both greater than the threshold value, the current direction determination unit 16 is instructed to start processing. In addition, the accuracy of the current direction determination may be improved by adjusting the voltage level of the magnetic field component output from the coils C1 and C2 to the voltage determination unit 12.

  The A / D converter 13 receives the trigger from the voltage determination unit 12 and performs A / D conversion on the voltage output from the coil C3 and passed through the LPF (Low Pass Filter). It is realized by an electronic circuit that converts it into an electrical signal. The effective value duration measurement unit 14 is a part that measures the effective value and duration of the voltage from the digital waveform output from the A / D conversion unit 13, and is realized by an electronic circuit that processes the digital waveform. The own tower accident determination unit 15 compares the effective value and duration of the voltage measured by the effective value duration measurement unit 14 with the threshold value stored in the threshold value storage unit 11, and the own tower (the detection system 1 is installed). It is determined whether or not there is an accident. The current direction determination unit 16 takes the difference between the voltage output by the coil C1 with the change of the surge magnetic field and the voltage output by the coil C2 with the change of the surge magnetic field, and the failure of the power line EW according to the positive / negative of the difference Determine the direction of the surge current. The determination result output part 17 is a part which outputs the determination result of the own tower accident determination part 15 and the electric current direction determination part 16, and may display it on a display and may notify another apparatus through a network.

  In addition, the voltage determination part 12, the own tower failure determination part 15, and the current direction determination part 16 are implement | achieved when CPU (Central Processing Unit) runs the program stored in the predetermined memory. Moreover, although the coils C1, C2, and C3 are installed on the tower base of the steel tower, the installation locations of the other parts 11 to 17 are not limited to the steel tower.

  FIG. 5 is a flowchart showing the processing of the detection system 1. In the detection system 1, first, the voltage determination unit 12 determines whether or not the voltage output from the coil C2 is greater than a threshold value (S501). If the voltage of the coil C2 is less than or equal to the threshold (NO in S501), the determination in S501 is repeated. If the voltage of the coil C2 is greater than the threshold (YES in S501), the voltage determination unit 12 determines whether the voltage output from the coil C1 is greater than the threshold (S502).

  If the magnetic field of the coil C1 is smaller than or equal to the threshold (NO in S502), the own tower accident determination unit 15 determines whether or not the own tower accident occurred (S503). For example, the effective value of the voltage output by the coil C3, converted by the A / D conversion unit 13, and measured by the effective value duration measurement unit 14 is equal to or greater than the threshold value (predetermined value) stored in the threshold value storage unit 11, In addition, it is determined whether or not the duration time of the measured voltage is equal to or longer than 3 cycles (= 0.05 seconds) of 60 Hz that is the stored threshold value. The 60 Hz three-cycle period is the time from the occurrence of a ground fault to the disconnection of the substation circuit breaker in response to an instruction from the control station. In order to determine that it is an accident in the own tower, it is necessary to certify the fact that sufficient commercial frequency current has continued for a sufficient amount of time.

  If the accident is not in the own tower (NO in S503), the process returns to the determination in S501. If the accident is in the own tower (YES in S503), the determination result output unit 17 outputs that the accident is in the own tower.

  If the magnetic field of the coil C1 is larger than the threshold value in S502 (YES in S502), the current direction determination unit 16 determines the direction of the fault surge current of the power line EW (S505). And the determination result output part 17 outputs that it is an other tower accident and the direction of a failure surge current (S506).

  According to the embodiment of the present invention described above, in the detection system 1 in which the coil is installed near the ground, by taking the difference between the surge magnetic field detected by the coil C1 and the surge magnetic field detected by the coil C2. The direction of the magnetic field due to the fault surge current flowing through the power line EW is known. According to this, a fault surge current in a desired power line and an induced surge current that is unnecessary noise can be separated near the ground, and the direction of the fault surge current can be determined.

  Further, when the coil 3 detects the commercial frequency magnetic field near the ground, it can be known that a ground fault has occurred in the steel tower where the detection system 1 is installed.

  According to the above, since the accident section is specified using the coil installed near the ground, dangerous high place work is eliminated and the installation work cost and the maintenance cost of the detection system 1 can be reduced.

  As mentioned above, although the form for implementing this invention was demonstrated, the said embodiment is for making an understanding of this invention easy, and is not for limiting and interpreting this invention. The present invention can be changed and improved without departing from the gist thereof, and equivalents thereof are also included in the present invention.

1 Detection system (accident detection system)
DESCRIPTION OF SYMBOLS 12 Voltage determination part 13 A / D conversion part 14 RMS value continuation time measurement part 15 Self tower failure determination part 16 Current direction determination part C1 coil (1st coil)
C2 coil (second coil)
C3 coil (third coil)
EW power line

Claims (5)

An accident location detection system that detects the location of an accident that occurred in a power line installed on a steel tower,
Among the towers, the fault surge current and the induced surge are installed near the ground, perpendicular to both the direction of the fault surge current flowing through the power line and the direction of the induced surge current flowing through the tower base of the tower. A first coil that detects a first surge magnetic field that is a magnetic field due to an electric current;
Among the steel towers, a second surge magnetic field is installed near the ground, parallel to the direction of the fault surge current and perpendicular to the direction of the induced surge current, and is a magnetic field caused by the induced surge current. A second coil;
A current direction determination unit that determines the direction of the fault surge current based on a difference between the first surge magnetic field detected by the first coil and the second surge magnetic field detected by the second coil. When,
An accident point detection system comprising: The accident point detection system according to claim 1,
The current direction determination unit
The difference between the voltage output by the first coil in accordance with the change of the first surge magnetic field and the voltage output by the second coil in accordance with the change of the second surge magnetic field is taken. A fault location detection system, characterized in that the direction of the fault surge current is determined according to the sign of. The accident location detection system according to claim 1 or claim 2,
Among the towers, near the ground, parallel to the direction of the fault surge current and perpendicular to the direction of the commercial frequency current flowing through the tower legs of the tower, the commercial frequency which is a magnetic field by the commercial frequency current A third coil that detects a magnetic field and outputs a first voltage;
An A / D converter that performs A / D conversion on the first voltage output from the third coil and outputs the second voltage as a second voltage;
When the state in which the effective value of the second voltage output from the A / D converter is equal to or greater than a predetermined value continues for a predetermined time or more, it is determined that an accident has occurred in the tower where the third coil is installed. Own steel tower accident judgment department,
An accident location detection system further comprising: An accident point detection system according to any one of claims 1 to 3,
The accident location detection system, wherein the first coil and the second coil are installed on concentric circles centered on the axis of the tower base and have the same electromagnetic induction characteristics. An accident section identification method for identifying an accident section in the power line using the accident location detection system according to any one of claims 1 to 4,
For each of the plurality of towers connected, the step of installing the first coil and the second coil near the ground among the towers;
When an accident occurs in the power line, obtaining the direction of the fault surge current determined by the current direction determination unit for each of the towers;
When the direction of the fault surge current determined by the current direction determination unit related to two adjacent towers is reversed, the step of identifying the interval between the two towers as an accident section;
A method for identifying an accident section, characterized in that

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