JP4786436B2 - Ground fault monitoring device and ground fault monitoring method - Google Patents

Description

  The present invention relates to a ground fault monitoring apparatus and a ground fault monitoring method that detect an actual ground fault occurring during a power distribution system artificial ground fault test and enable a quick accident recovery procedure.

  Conventionally, a technique for quickly detecting a ground fault with high accuracy has been proposed. For example, Patent Document 1 proposes a technique for calculating a ground fault current including a fine ground fault with high accuracy without being affected by a ground fault outside the protection range. According to Patent Document 2, an operator can quickly identify the occurrence of a ground fault and identify the area from the state of the operation signal output when detecting a ground fault in all ground fault relays and all ground fault direction relays installed in the high-voltage power system. Is a ground fault monitoring device for a high-voltage power supply system. Patent Document 3 proposes a technique for performing high-accuracy ground fault monitoring with a small number of coefficients using numerical values measured by an artificial ground fault test.

  By the way, when an actual ground fault accident (hereinafter referred to as an actual ground fault accident) occurs during an artificial ground fault test, an abnormal voltage has been generated by connecting a voltmeter or a ground fault overvoltage relay next to GPT3. Whether the ground fault voltage is generated by the test (artificial grounding) when the relay is in operation, or is the ground fault by the test comprehensively including the switchboard display, etc. Judging whether it was a real fault.

  However, when a new artificial ground fault testing device that automatically performs measurement is introduced, even a test worker can quickly determine whether or not the ground fault is due to the operation of the new artificial ground fault testing device. It is becoming difficult to judge. For this reason, when an actual ground fault occurs in the power distribution system, it cannot be quickly shut down, and there are concerns about the impact on customers and the failure of the power distribution system and substation equipment.

In addition, switchboard alarm displays frequently occur during testing, but the test location is often far from the alarm display, leading to an increase in on-site personnel for confirming and stopping alarms.
JP-A-11-271384 Japanese Patent Laid-Open No. 11-202018 Japanese Patent Laid-Open No. 9-257858

  The present invention has been made in view of the above-described circumstances, and can be monitored by a small number of on-site personnel, and can detect a real ground fault accident that occurs during an artificial ground fault test quickly and accurately, and can perform appropriate blocking. An object of the present invention is to provide a ground fault monitoring device and a ground fault monitoring method that can be connected to a manual trip of a machine.

  In order to achieve the above object, a ground fault monitoring apparatus according to the present invention captures an alarm input / display means for capturing and displaying a simulated ground fault signal for a ground fault test, and captures an output signal of a GPT connected to a distribution system. A ground fault overvoltage detecting means that operates when the output signal exceeds a predetermined value, a feeder DG operation state input means for taking in an operation state of one or more feeder ground fault direction relays and displaying the operation state; There is provided a ground fault detecting means for detecting a ground fault when the ground fault over voltage is detected by the fault over voltage detecting means and when the ground fault direction relay of any feeder is operated.

  In the present invention, a GPT tertiary voltage signal, for example, is taken into the ground fault monitoring device as a GPT output signal, and this voltage signal is compared with a predetermined value set in advance. Outputs an overvoltage detection signal. Then, when this ground fault overvoltage detection signal is output and the ground fault direction relay of one of the feeders is operated, an actual ground fault detection display is displayed to notify that a ground fault has actually occurred. As a result, an actual ground fault accident during the artificial ground fault test can be detected, which can lead to measures such as a manual breaker operation.

  The ground fault monitoring apparatus according to the present invention is further characterized by further comprising a settling value setting means for setting a predetermined value of the ground fault overvoltage detection means.

  In the present invention, since the output signal of the GPT changes due to a normal load fluctuation, the threshold for overvoltage detection can be set.

  The ground fault monitoring apparatus according to the present invention is further characterized in that the alarm input / display means captures and displays an alarm signal for each type.

  Preferably, the ground fault monitoring device is provided with means for outputting an alarm stop and display return signal for the alarm signal. As a result, it is possible to cope with the alarm signal from the ground fault monitoring device, and it is possible to reduce the number of on-site personnel.

  Moreover, it is preferable that the power supply for input / output of the alarm signal and the power supply for operation of the ground fault monitoring device have different voltages. Not only changing the power supply system but also changing the power supply voltage can prevent malfunctions such as erroneous shut-off due to power wraparound.

  A ground fault monitoring method according to the present invention is a method of monitoring the occurrence of an actual ground fault occurring during an artificial ground fault test using the above ground fault monitoring apparatus, and comprising an artificial ground fault from an alarm means of the ground fault monitoring apparatus. If there is an alarm sound of the occurrence of a ground fault during the test, confirm the occurrence of the actual ground fault by the presence or absence of the actual ground fault detection display output by the actual ground fault detection means, and if there is an actual ground fault detection display, Check the operation status of the ground fault direction relay of each distribution line by displaying the feeder DG operation status input means, and if any ground fault direction relay is operating, interrupt the artificial ground fault test and It is characterized by hand cutting.

  In the present invention, it is possible to accurately grasp an actual ground fault accident during an artificial ground fault test by performing confirmation and operation according to a predetermined procedure in accordance with the display of the ground fault monitoring device, and when the accident occurs, the corresponding circuit breaker can be quickly found. Can be cut off.

  According to the present invention, by collecting information in the ground fault monitoring device, it is possible to monitor with a small number of on-site personnel, and it is possible to quickly and accurately detect an actual ground fault accident that occurs during an artificial ground fault test.

  Embodiments of the present invention will be described below. FIG. 1 is a functional block diagram of the ground fault monitoring apparatus according to the first embodiment.

  In this figure, a ground fault monitoring device 1 takes in a power supply unit 11 for operating this device, a power supply display means 12 for displaying a power on / off state, and an output signal of a GPT connected to a power distribution system. The ground fault overvoltage detection means 13 that operates when the output signal exceeds a predetermined value, the setting value setting means 14 that sets a threshold value for operating the ground fault overvoltage detection means 13, and the operation state of the ground fault direction relay of the feeder are fetched. Feeder DG operation state input means 15 for displaying the state, actual ground fault detection means 16 for determining the presence or absence of actual ground faults based on the various signals taken in, and taking in and displaying a simulated ground fault signal for ground fault testing Alarm input / display means 17 for outputting, alarm means 18 for outputting an alarm signal when a ground fault is detected, and switchboard alarm stop means 19 for outputting a signal for stopping the alarm of the switchboard. To have.

  FIG. 2 shows an example of a circuit corresponding to each of the above means. In this figure, the ground fault overvoltage detection means 13 connects the electric wire from the voltage sensor 21 under the lower plug of the GPT tertiary PTT, compares the input voltage with the set value set by the set value setting means 14, and setstling. When a voltage V0 greater than the value is detected, the contact 22 of the voltage sensor 21 is closed and the OVG relay 23 is operated. As a result, an alarm is output from the BZ (buzzer) 24.

  On the other hand, when a feeder DG operation state signal (an operation signal of the ground fault direction relay) is input from the switchboard to the feeder DG operation state input means 15, any of the LEDs 8 to 13 corresponding to each feeder is turned on. In the actual ground fault detection means 16, the LED 2 is turned on when the contact of the OVG relay 23 is closed. Further, when the contact of the OVG relay 23 is closed and the operation signal of the ground fault direction relay of one of the feeders is input, the LED 3 which is an actual ground fault detection display is turned on.

  The alarm input / display means 17 receives a simulated ground fault signal (OVG display) from the artificial ground fault testing apparatus. In addition, an electric station failure display panel bell alarm pulse (BLB), an electric station failure display panel buzzer alarm pulse BZB, and an electric station failure display panel chime alarm pulse CHB are input as the distribution panel alarm pulses.

  The switchboard alarm stop means 19 is configured to output an alarm stop / display return signal to a device that outputs a fault alarm such as a fault display panel by pressing a button. FIG. 3 shows the appearance of the ground fault monitoring device 1. Push button switches, LEDs, instruments, terminals, etc. are arranged at the top of the device.

  Next, a procedure for monitoring a ground fault using the ground fault monitoring apparatus 1 will be described with reference to FIG. When an alarm is sounded from the alarm means 18 of the ground fault monitoring device 1, first, the presence / absence of OVG display on the switchboard (the lighting state of the LED 4) is confirmed (S101). Then, if there is no OVG display, and if there is a switchboard BL alarm occurrence and switchboard CH alarm occurrence display, that is, if any of the LEDs 5 to 7 is lit (S102), then an artificial ground is detected as an electrical station failure. The fault test is interrupted and a fault point search is performed (S103).

  If there is an OVG display on the switchboard in step S101, then the presence / absence of a “ground fault occurrence” display (LED2) is checked (S104). If there is no “earth fault occurrence” display (“NO” in S104), the presence / absence of “switchboard BZ alarm generation” display (LED6) is checked (S105), and if there is a BZ alarm generation display (“YES” in S105). ) As an alarm by the artificial ground fault test (S106), the "Distribution board alarm stop" and "Distribution panel display return" buttons are pressed to perform the alarm / display recovery procedure (S107). If “NO” in the step S105, the procedure after the step S102 is executed.

  On the other hand, if “YES” in the step S104, the operation state of the ground fault direction relay of each distribution line is examined as the feeder DG operation state (S108). When any of the ground fault direction relays is operating, that is, when any of the LEDs 8 to 13 is lit (“YES” in S108), the “actual ground fault” display (LED 3) is lit ( (S111) At this time, the artificial ground fault test is interrupted, and the corresponding distribution line is manually cut off by the switch gear (S112). On the other hand, if “NO” in the step S108, the distribution line “fine ground fault” is set (S109), the artificial ground fault test is interrupted, and the distribution line is switched by the switch gear based on the operating state of the ground fault direction relay. Cut through sequentially.

  As described above, according to the present embodiment, the ground fault monitoring device captures the electrical signal of the GPT tertiary PTT and the feeder DG operation state signal to perform the actual ground fault monitoring, captures the alarm display of the switchboard, and the display signal and the actual ground fault. Depending on the monitoring status, ground faults caused by artificial ground fault tests or ground faults caused by actual ground faults are separated and countermeasures are implemented, so monitoring is possible with a small number of on-site personnel, and they occur during artificial ground fault tests. It is possible to quickly and accurately detect an actual ground fault.

  The present invention can be used for monitoring a ground fault in a power system.

It is a functional block diagram of the ground fault monitoring apparatus by the 1st Embodiment of this invention. FIG. 2 is a developed connection diagram of the ground fault monitoring device of FIG. 1. FIG. 2 is a layout diagram of switches, LEDs, meters, and the like of the ground fault monitoring device of FIG. 1. It is a flowchart for demonstrating the procedure of the ground fault monitoring method by the 1st Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Ground fault monitoring apparatus 11 Power supply part 12 Power supply display means 13 Ground fault overvoltage detection means 14 Setting value setting means 15 Feeder DG operation state input means 16 Actual ground fault detection means 17 Alarm input / display means 18 Alarm means 19 Switchboard alarm stop means 21 Voltage sensor 22 Voltage sensor contact 23 OVG relay 24 BZ (buzzer)

Claims (2)

Alarm input / display means for taking in a simulated ground fault signal for ground fault testing and an alarm signal from the switchboard and displaying the status of each signal ;
A ground fault overvoltage detection means that takes in an output signal of a GPT connected to a power distribution system and operates when the output signal becomes a predetermined value or more;
Settling value setting means for setting the predetermined value of the ground fault overvoltage detection means;
Feeder DG operation state input means for capturing the operation state of the ground fault direction relay of two or more feeders and displaying the operation state respectively ;
It performs ground fault occurrence displayed upon detection of a ground fault over-voltage by the ground fault over-voltage detection means detects the ground fault over voltage and ground fault the direction of one of the feeder of the earth fault directional relay of two or more feeders a hands-fault detection means for performing hands-fault failure display when the relay is activated,
Means for outputting an alarm stop and display return signal for the alarm signal;
A ground fault monitoring device characterized by comprising: A method for monitoring the occurrence of an actual ground fault occurring during an artificial ground fault test using the ground fault monitoring device according to claim 1 ,
If there is an alarm ringing of the ground fault occurs in artificial ground fault test from the alarm means of the ground絡監vision device, the confirmation of the earth絡発raw by the presence or absence of the earth絡発raw display output by the hands fault detection means As a result of confirming the occurrence of the ground fault, if there is no ground fault occurrence display and an alarm signal is displayed from the switchboard, it is determined that the alarm is due to the artificial ground fault test, and the alarm is stopped and displayed for the alarm signal. and to recover the land絡発raw confirmation result, when there is land絡発raw display, then check the operation status of the earth fault directional relay of each distribution line by a display of the feeder DG operating state input means, If any of the ground fault direction relays is operating, interrupt the artificial ground fault test and cut off the corresponding feeder, while if any of the ground fault direction relays are not operating, It is judged that the artificial ground Earth絡監vision method characterized by sequentially Tedan feeder interrupt the test.

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