JP5036850B2 - Accident direction indicator - Google Patents

Description

  The present invention relates to an accident direction display device, and in particular, an accident direction display device that determines and displays the direction of an accident point when a ground fault or short circuit accident occurs on a high-voltage distribution line connected with a distributed power source. About.

  On the high-voltage distribution line (for example, 6.6 kV) that supplies electricity to the customer from the substation, the point of the accident when a ground fault or short-circuit accident occurs for the purpose of early detection and quick recovery of the accident point. An accident direction display device that determines and displays an accident direction that is the direction of the vehicle is installed (see, for example, Patent Document 1).

This accident direction display device monitors the zero-phase voltage (V ₀ ) and zero-phase current (I ₀ ) in the event of a ground fault, and determines the accident direction based on the phase difference between the zero-phase voltage and the zero-phase current generated by the accident To do. In the case of a short circuit accident, the direction of the accident is determined based on the phase difference between the short circuit current (I) and the voltage (V) generated by the accident. For example, if the accident point is located on the substation side when viewed from the accident direction display device, the accident direction is determined as the power source side. Conversely, if the accident point is located on the demand side, the accident direction is determined as the load side. To do.

JP-A-2-275373

  However, in recent years, the spread of distributed power sources such as solar power generation and wind power generation has progressed, and the number of high-voltage distribution lines connected to the distributed power sources has increased. When a ground fault or short circuit accident occurs on the high-voltage distribution line, a distributed power source linked to the high-voltage distribution line may cause the voltage or current at the time of the accident to be accompanied by a large frequency fluctuation. This frequency variation is prominent during the moment when an accident event occurs from the substation shutdown operation to the disconnection of the distributed power source.

  Such frequency fluctuation is a cause of misjudgment of accident direction. That is, in the determination of the accident direction based on the above-described phase difference, only the phase difference is measured. Therefore, if the frequency greatly varies as described above, it may be difficult to measure the correct phase difference. If the correct phase difference is not measured and the wrong phase difference is used to determine the accident direction, an erroneous determination of the accident direction occurs, and the erroneous accident direction is displayed.

  The present invention has been made in view of the above, and an object of the present invention is to prevent a reduction in the accuracy of accident direction determination due to a frequency fluctuation of voltage or current at the time of an accident, and to accurately determine and display the accident direction. It is to provide an accident direction display device.

  According to a first aspect of the present invention, in the accident direction display device, a detection unit that detects a voltage and a current that change due to a ground fault or a short-circuit accident on the main line of the high-voltage distribution line to which the distributed power supply is linked, and A processing unit that determines an accident direction that is a direction of an accident point on the main line using the phase of the voltage and the current detected by the detection unit, and a display that notifies the accident direction determined by the processing unit A display unit that performs the detection, the detection unit detects a frequency of a voltage or a current that changes due to a ground fault or a short circuit accident, and the processing unit detects a frequency of the voltage or the current that is detected by the detection unit. If the voltage or current frequency is not within the allowable range, the process for determining the accident direction is stopped, and the voltage or current frequency is within the allowable range. If it is determined that there is to resume the process of determining the accident direction.

  According to a second feature of the present invention, in the accident direction display device according to the first feature described above, the detection unit includes, as the voltage and the current, a zero-phase voltage and a zero-phase current caused by a ground fault, A short circuit current generated by a short circuit accident and a voltage before the short circuit accident are detected, and the processing unit detects the voltage before the short circuit accident detected by the detection unit, and the first allowable range and the second allowable range. A storage unit for storing, performing a first determination process for determining the accident direction using a phase difference between the zero-phase voltage and the zero-phase current detected by the detection unit, and detected by the detection unit; A processing unit that performs a second determination process for determining the accident direction using a phase difference between the short-circuit current that has been performed and the voltage before the short-circuit accident stored in the storage unit, and is detected by the detection unit The frequency of the zero-phase voltage is It is determined whether or not the first allowable range stored in the storage unit is within the first allowable range, and when it is determined that the frequency of the zero-phase voltage is not within the first allowable range, the first determination process is stopped. When the frequency of the zero-phase voltage is determined to be within the first allowable range, the first determination process is resumed, and the frequency of the short-circuit current detected by the detection unit is stored in the storage unit. If the frequency of the short-circuit current is determined not to be within the second allowable range, the second determination process is stopped and the short-circuit current is When it is determined that the frequency is within the second allowable range, the second determination process is restarted.

  According to the first feature of the present invention, the frequency of the voltage or current on the main line is detected by the detection unit, and the detected frequency of the voltage or current is monitored by the processing unit. When the voltage or current frequency falls outside the allowable range by this monitoring, the process for determining the accident direction is stopped, and when the voltage or current frequency falls within the allowable range, the process for determining the accident direction is resumed. Thus, as a monitoring item in the accident direction determination, in addition to the phase of voltage and current, the frequency of voltage or current is added, and the accident direction determination process is stopped based on the frequency, so the voltage or voltage with a large frequency fluctuation is The accident direction determination process is not performed using the current, and the erroneous determination of the accident direction due to the frequency fluctuation can be avoided. As a result, it is possible to prevent a reduction in the accuracy of the accident direction determination due to the frequency fluctuation of the voltage or current at the time of the accident, and to accurately determine and display the accident direction.

  According to the second feature of the present invention, the processing unit responds to both the occurrence of a ground fault and a short-circuit accident, and the processing for determining the accident direction as described above is stopped by the processing unit. Even if a ground fault accident or a short-circuit accident occurs, it is possible to prevent the deterioration of the accuracy of the accident direction judgment due to the frequency fluctuation of the voltage or current at the time of the accident, and to accurately determine and display the accident direction .

It is a figure which shows schematic structure of the accident direction display apparatus on the high voltage distribution line which concerns on embodiment of this invention. It is explanatory drawing for demonstrating the ground fault accident process which the accident direction display apparatus shown in FIG. 1 performs. It is explanatory drawing for demonstrating the determination range used for the accident direction determination process in the ground fault accident process shown in FIG. It is explanatory drawing for demonstrating the short circuit accident process which the accident direction display apparatus shown in FIG. 1 performs. It is explanatory drawing for demonstrating the determination range used for the accident direction determination process in the short circuit accident process shown in FIG.

  An embodiment of the present invention will be described with reference to the drawings.

  As shown in FIG. 1, a plurality of accident direction display devices 1 according to an embodiment of the present invention are provided on a main line 3 a of a high-voltage distribution line 3 connected to a substation 2. A distributed power source 4 such as solar power generation or wind power generation is linked to the main line 3a by a branch line 3b. Moreover, the circuit breaker 5 is provided on the trunk line 3 a, and this circuit breaker 5 is positioned between the substation 2 and the accident direction display device 1. The circuit breaker 5 disconnects the high-voltage distribution line 3 from the substation 2 according to an instruction from the substation 2 in response to the occurrence of a ground fault or a short circuit accident.

  The accident direction display device 1 described above includes a detection unit 1a that detects each phase voltage and current of each of the three phases of the main line 3a, a processing unit 1b that performs various processes such as a ground fault process and a short circuit process, And a display unit 1c that performs a display for notifying a person or the like of the accident direction.

  The detection unit 1a detects each phase voltage of each of the three phases of the trunk line 3a, each phase current, and their frequencies using a plurality of coupling capacitors for phase voltage detection, a plurality of current transformers for phase current detection, and the like. The zero-phase voltage, zero-phase current and their frequency generated by the ground fault are output to the processing unit 1b, and the short-circuit current, voltage and their frequency generated by the short-circuit accident are also output to the processing unit 1b. Each coupling capacitor and each current transformer are provided for each of the three-phase R, S, and T phases.

  The processing unit 1b detects the occurrence of a ground fault using the zero-phase voltage and the zero-phase current output by the detection unit 1a, and further uses the phase of the zero-phase voltage and the zero-phase current on the main line 3a. Ground fault processing is performed to determine the direction of the accident, which is the direction of the accident point (details will be described later). Further, the processing unit 1b detects the occurrence of a short-circuit accident using the phase current output by the detection unit 1a, that is, the short-circuit current, and further, the short-circuit current output by the detection unit 1a and the voltage before the short-circuit accident (normal A short-circuit accident process for determining the accident direction using the phase of the voltage is performed (details will be described later).

  Here, in the determination of the accident direction described above, when the accident point is located on the substation 2 side as viewed from the accident direction display device 1, the accident direction is determined as the power source side, and conversely, when the accident point is located on the demand side. Determine the direction of the accident as the load side. After this determination, the processing unit 1b outputs an accident occurrence detection and accident direction information to the display unit 1c. The processing unit 1b includes a storage unit 11 that stores various types of information used for the various types of processing described above.

  The display unit 1c performs display for notifying the operator of the accident direction of the ground fault or short circuit accident based on the detection of the occurrence of the accident and the accident direction information output from the processing unit 1b. As the display unit 1c, for example, a magnetic reversal display is used. However, when the accident direction display device 1 is provided with a power source such as a solar battery or a charging place, and power is supplied from the power source to the display unit 1c, an indicator lamp such as an LED lamp or LED is used as the display unit 1c. A display or the like may be used.

  For example, the display unit 1c performs a display notifying the occurrence of the accident only when the accident direction is the load side. Since a plurality of accident direction display devices 1 are provided on the main line 3a of the high-voltage distribution line 3, the display is performed only when the accident direction is on the load side. It is possible to notify the operator of whether or not it exists. As a result, early detection of accident points and quick recovery can be realized.

  Next, the ground fault accident process performed by the processing unit 1b will be described in detail.

As shown in FIG. 2, the zero-phase voltage (V ₀ ) and the zero-phase current (I ₀ ) are input from the detection unit 1a to the processing unit 1b. When the zero-phase voltage reaches its set value (step S1), and when the zero-phase current reaches its set value (step S2), the phase difference between these zero-phase voltage and zero-phase current is calculated, and the phase difference Based on the above, the accident direction of the ground fault on the main line 3a is determined (step S3), and it is further determined whether or not the determination result of the accident direction has been maintained for a predetermined time or more (step S4). Further, the frequency of the aforementioned zero-phase voltage is monitored, and it is determined whether or not the frequency of the zero-phase voltage is within a first allowable range (for example, rated frequency ± 1.1 Hz) (step S5). The first allowable range is stored in the storage unit 11, and is read and used as necessary.

  If a ground fault occurs, the zero-phase voltage and zero-phase current will be equal to or higher than their settling values, so a comparison between the zero-phase voltage and the settling value and a comparison between the zero-phase current and the settling value will cause a ground fault. It is possible to detect the occurrence of an accident. For example, in the case of the high voltage distribution line 3 of 6 kV, when the set value of the zero phase voltage is 380 V and the set value of the zero phase current is 100 mA, the level of the zero phase voltage reaches 380 V and the level of the zero phase current is When 100 mA is reached, the occurrence of a ground fault will be detected.

  After that, it is determined in step S4 that the accident direction determination result has been maintained for a predetermined time or more, and in step S5, if the frequency of the zero-phase voltage is determined to be within the first allowable range, Since the zero-phase voltage and the zero-phase current have reached the respective set values, the occurrence detection of the ground fault and the accident direction information are output to the display unit 1c when the AND condition is satisfied (step S6).

  On the other hand, if it is determined in step S5 that the frequency of the zero phase voltage is not within the first allowable range, the fault direction determination process for the ground fault in step S3 is stopped, and the AND condition is not satisfied. Thereafter, when it is determined again in step S5 that the frequency of the zero-phase voltage is within the first allowable range, the fault direction determination process for the ground fault in step S3 described above is resumed. This avoids the use of zero-phase voltage and zero-phase current with large frequency fluctuations in the fault direction determination process for ground faults, and prevents erroneous determination of the accident direction.

  Here, in the above-described fault direction determination process of the ground fault, for example, as shown in FIG. 3, the phase difference between the zero-phase voltage and the zero-phase current, that is, the phase angle 0 ° of the zero-phase voltage is used as a reference. When the phase of the zero-phase current is within a range of −30 ° to + 150 °, it is determined that the accident direction is the load side. On the other hand, when the phase of the zero-phase current is not within the range of −30 ° to + 150 °, that is, within the range of + 150 ° to −30 °, it is determined that the accident direction is the power supply side. These determination ranges are stored in the storage unit 11, and are read and used as necessary.

  Next, the short-circuit accident process performed by the processing unit 1b will be described in detail.

  As shown in FIG. 4, the phase current (I) and the phase voltage (V) are input from the detection unit 1a to the processing unit 1b. First, the voltage phase before the short-circuit accident, that is, before the occurrence of the short-circuit current is stored in the storage unit 11 (step S11). Thereafter, when the phase current reaches the set value (step S12), the phase difference between the short-circuit current that is the phase current and the voltage stored in the storage unit 11 is calculated, and an accident of a short-circuit accident is calculated based on the phase difference. The direction is determined (step S13), and it is further determined whether or not the determination result of the accident direction has been maintained for a predetermined time or more (step S14). In addition, the frequency of the above-described phase current, that is, the short-circuit current caused by the short-circuit accident is monitored, and whether or not the frequency of the short-circuit current is within a second allowable range (for example, the frequency before the accident ± 0.6 Hz). Determination is made (step S15). The second allowable range is stored in the storage unit 11, and is read and used as necessary.

  When a short circuit accident occurs, the phase current becomes equal to or higher than the set value, and therefore it is possible to detect the occurrence of the short circuit accident by comparing the phase current with the set value. For example, in the case of the small-capacity high-voltage distribution line 3, if the set value of the phase current is 300A, the occurrence of a short circuit accident is detected when the phase current level reaches 300A. Further, in the case of the high-capacity high-voltage distribution line 3, when the set value of the phase current is set to 600A, the occurrence of a short-circuit accident is detected when the level of the phase current reaches 600A.

  After that, it is determined in step S14 that the accident direction determination result is maintained for a predetermined time or more, and in step S15, it is determined that the frequency of the short-circuit current is within the second allowable range. Since the above-described phase current has reached a set value, detection of occurrence of a short circuit accident and accident direction information are output to the display unit 1c when the AND condition is satisfied (step S16).

  On the other hand, if it is determined in step S15 that the frequency of the short-circuit current is not within the second allowable range, the accident direction determination process for the short-circuit accident in step S13 is stopped, and the AND condition is not satisfied. Thereafter, when it is determined again in step S15 that the frequency of the short-circuit current is within the second allowable range, the accident direction determination process for the short-circuit accident in step S13 described above is resumed. Thereby, it is avoided to use a short-circuit current with a large frequency fluctuation in the accident direction determination process of the short-circuit accident, and erroneous determination of the accident direction is prevented.

  Here, in the accident direction determination process of the short-circuit accident described above, for example, as shown in FIG. 5, the phase difference between the short-circuit current and the voltage before the short-circuit accident, that is, the phase angle 0 ° of the voltage before the short-circuit accident is used as a reference. When the phase of the short circuit current is within the range of −30 ° to + 110 °, it is determined that the accident direction is the load side. On the other hand, when the phase of the short circuit current is within the range of + 150 ° to −70 °, it is determined that the accident direction is the power supply side. These determination ranges are stored in the storage unit 11, and are read and used as necessary.

  In such ground fault accident processing and short-circuit accident processing, the phase difference between the zero-phase voltage and the zero-phase current detected by the detection unit 1a is used in the fault direction determination processing of the ground fault accident. A first determination process for determining the direction is performed. Further, in the accident direction determination process of the short circuit accident, the phase difference between the short circuit current detected by the detection unit 1a and the voltage before the short circuit accident stored by the storage unit 11 is used to determine the accident direction of the short circuit accident. 2 determination processing is performed. The first determination process and the second determination process are stopped by the processing unit 1b according to the frequency fluctuation of the voltage or current at the time of the accident, and the erroneous determination of the accident direction due to the frequency fluctuation is avoided.

  For example, when a ground fault occurs, it is determined whether the frequency of the zero-phase voltage detected by the detection unit 1a is within the first allowable range stored by the storage unit 11, and the zero-phase is detected. When it is determined that the frequency of the voltage is not within the first allowable range, the first determination process described above is stopped, and when the frequency of the zero-phase voltage is determined to be within the first allowable range, The first determination process is resumed. When a short circuit accident occurs, it is determined whether or not the frequency of the short circuit current detected by the detection unit 1a is within the second allowable range stored by the storage unit 11, and the frequency of the short circuit current is determined. Is determined not to be within the second allowable range, the above-described second determination process is stopped, and when it is determined that the frequency of the short-circuit current is within the second allowable range, the above-described second determination process is stopped. The determination process is resumed.

  As described above, according to the accident direction display device 1 according to the embodiment of the present invention, the frequency of the voltage or current on the main line 3a is detected by the detection unit 1a, and the detected voltage or current frequency is processed. Monitored by the unit 1b. When the voltage or current frequency falls outside the allowable range due to this monitoring, the accident direction determination process (first determination process or second determination process) is stopped, and when the voltage or current frequency falls within the allowable range, it stops. The accident direction determination process is resumed. As described above, in addition to the voltage and current phases, the voltage or current frequency is added as a monitoring item in the accident direction determination process, and the accident direction determination process is stopped based on the frequency. Alternatively, the accident direction determination process is not performed using the current, and it is possible to avoid erroneous determination of the accident direction due to frequency fluctuation. As a result, it is possible to prevent a reduction in the accuracy of the accident direction determination due to the frequency fluctuation of the voltage or current at the time of the accident, and to accurately determine and display the accident direction.

  In addition, the processing unit 1b responds to both occurrences of ground faults and short circuit accidents, and the processing unit 1b stops the accident direction determination processing (first determination processing and second determination processing) as described above. Therefore, in the event of either a ground fault or a short-circuit accident, the accuracy of accident direction determination due to voltage or current frequency fluctuations at the time of the accident is prevented, and the accident direction is accurately determined and displayed. be able to.

  In addition, the above-mentioned embodiment which concerns on this invention is an illustration, and the scope of the invention is not limited to them. The above-described embodiment can be variously modified. For example, some components may be deleted from all the components shown in the above-described embodiment, and further, components according to different embodiments may be appropriately combined. Also good. When configuring the processing unit 1b according to the above-described embodiment, the processing unit 1b may be configured using both hardware and software, or the processing unit 1b may be configured using either one of them. You may do it. In the above-described embodiment, the first allowable range and the second allowable range may be set to different ranges, or may be set to the same range. Further, both the first determination process and the second determination process may be performed simultaneously in parallel, or only one of them may be performed.

DESCRIPTION OF SYMBOLS 1 Accident direction display apparatus 1a Detection part 1b Processing part 1c Display part 3 High voltage distribution line 3a Trunk line 4 Distributed type power supply

Claims (2)

A detection unit for detecting a voltage and a current that change due to a ground fault or a short-circuit accident on a main line of a high-voltage distribution line connected to a distributed power source;
A processing unit that determines an accident direction that is a direction of an accident point on the trunk line using the phase of the voltage and the current detected by the detection unit;
A display unit for displaying the accident direction determined by the processing unit;
With
The detection unit detects the frequency of the voltage or current that changes due to a ground fault or a short circuit accident,
The processing unit determines whether the frequency of the voltage or the current detected by the detection unit is within an allowable range, and determines that the accident occurs when the frequency of the voltage or the current is not within the allowable range. An accident direction display device characterized by stopping the process of determining the direction and restarting the process of determining the accident direction when it is determined that the frequency of the voltage or current is within an allowable range. The detector detects, as the voltage and the current, a zero-phase voltage and a zero-phase current caused by a ground fault, a short-circuit current caused by a short-circuit accident, and a voltage before the short-circuit accident,
The processor is
The storage unit stores the voltage phase before the short-circuit accident detected by the detection unit, and the first allowable range and the second allowable range, and the zero-phase voltage detected by the detection unit and the A first determination process is performed to determine the accident direction using a phase difference with a zero-phase current, and the short-circuit current detected by the detection unit and the voltage before the short-circuit accident stored by the storage unit A processing unit that performs a second determination process for determining the accident direction using a phase difference;
It is determined whether the frequency of the zero-phase voltage detected by the detection unit is within a first allowable range stored by the storage unit, and the frequency of the zero-phase voltage is within the first allowable range. If it is determined that the frequency of the zero-phase voltage is within the first allowable range, the first determination process is resumed.
It is determined whether the frequency of the short-circuit current detected by the detection unit is within the second allowable range stored by the storage unit, and the frequency of the short-circuit current is not within the second allowable range. When it is determined, the second determination process is stopped, and when it is determined that the frequency of the short-circuit current is within the second allowable range, the second determination process is resumed. The accident direction display device according to 1.

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