JP2019009948A - Accident point locating device - Google Patents

Abstract

To provide an accident point locating device of gas insulated switchgear with less gas leakage risk.SOLUTION: The accident point locating device identifies an accident point of a gas insulated switchgear which is equipped with multiple gas compartments containing conductors. When a detected current exceeds the predetermined value, the accident point in the gas compartments is identified on the basis of the signal from the recorded strain sensor.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an accident point locating device that enables a gas section in which an accident has occurred to be evaluated with a gas insulated switchgear.

  A gas-insulated switchgear is configured by connecting a number of gas compartments filled with gas as an insulating medium. Therefore, when an accident such as a ground fault or a short circuit occurs, it is necessary to promptly find the gas compartment (container) where the accident has occurred and repair or update it. However, it is difficult to determine in which pressure vessel the accident occurred visually from the outside. Since the gas is overheated and expands due to the arc generated at the time of the accident, it is thought that the pressure vessel where the accident occurred can be identified by monitoring the pressure in all the gas compartments constituting the gas insulated switchgear. .

  In Patent Document 1, a strain gauge 9 is disposed in a partition wall 10 provided outside the hermetic container 15 and communicating with the inside of the hermetic container between the first gas chamber and the second gas chamber. An internal accident in a gas insulation device is detected by detecting the pressure difference in the gas chamber.

JP-A-8-308046

  However, since the internal accident detection device in the above-mentioned patent document is configured to guide the gas in the sealed container to an external pressure sensor through a pipe, a plurality of seal portions are required for monitoring one sealed container, and there is a risk of gas leakage. was there.

    An object of the present invention is to provide an accident location system with a low risk of gas leakage.

  The object is to provide an accident point rating device for evaluating an accident point of a gas insulated switchgear having a plurality of gas compartments for accommodating conductors, each of which is attached to a metal pipe constituting the gas compartment, and the distortion of the metal pipe is reduced. A strain detecting means for detecting, a current detecting means for detecting a current flowing through the conductor, a recording device for recording a signal of the strain detecting means, and a processing means for performing a rating based on the signal of the recording device, When the current detected by the current detection means exceeds a predetermined value, the processing means evaluates the gas section at the accident point based on the signal recorded in the recording device.

  ADVANTAGE OF THE INVENTION According to this invention, the accident point location apparatus with few gas leak risks can be provided.

It is a block diagram of an accident division point location system. It is a figure which shows the attachment to the metal tube of a strain sensor. It is a figure showing an example of the single phase connection diagram of a gas insulated switchgear. It is a figure which shows the flowchart of accident point location. It is a figure which shows the example of an accident point display on a monitor screen. It is a figure which shows the relationship between the instantaneous value of an electric current, an effective value, and a threshold value. It is a block diagram which shows the calculation method of an effective value from the instantaneous value of an electric current. It is a figure which shows the output and calculation result of a strain sensor. It is a figure which shows the other flowchart of accident point location.

  Hereinafter, an example of an embodiment will be described with reference to the drawings.

  FIG. 1 is a system configuration diagram including a gas insulated switchgear and an accident point locating device according to the present embodiment.

  The gas insulated switchgear includes a plurality of gas compartments 1a, 2a, 3a filled with an insulating gas and a conductor 2 through which a high current flows. Here, the plurality of gas compartments 1a, 2a, 3a are composed of metal tubes 31a, 31b, 31c and insulating spacers 32a, 32b. In FIG. 1, the spacers at both ends constituting 1a and 3a are omitted. Moreover, the gas compartment which exists besides gas compartment 1a, 2a, 3a is also abbreviate | omitted.

  The accident point locating device includes axial strain sensors 3a, 3b, 3c installed on the outer surfaces of the metal pipes 31a, 32b, 33c constituting the gas insulated switchgear, and circumferential strain for measuring circumferential strain. Waveform recording unit 5 that can hold instantaneous waveforms of signals from sensors 4a, 4b, and 4c, current sensor 8 that detects signals from these strain sensors and current of conductor 2, waveform recording unit 5 and communication line 7 and a processing unit 6 connected for diagnosis and evaluation. Here, it is assumed that the current sensor 8 is appropriately attached to all ends as appropriate in the necessary portions of the unit of the gas insulated switchgear. Since the strain sensor is not exposed to the insulating gas in the gas compartment, there is little failure or deterioration.

  FIG. 2 is an enlarged view of the strain sensor mounting portion of FIG. The axial strain sensor 3b and the circumferential strain sensor 4b may be integrated sensors.

  FIG. 3 shows a double main bus system as an example of a single phase connection diagram of a gas insulated switchgear. In this example, there are 6 lines and terminals N1 to N6 are connected to external equipment. Each line is provided with current sensors 8a to 8f for measuring currents I1 to I6 flowing into the gas insulated switchgear, and these signals are input to the waveform recording unit 5.

  In FIG. 4, the fault point orientation performed by the processing unit 6 will be described with reference to a flowchart. The processing unit 6 constantly monitors the current sensor signal 8. First, in process S1, it is determined whether or not there is one in which the measured current of the current sensor signal 8 exceeds the rated current.

Here, since the current measured by the current sensor signal 8 is the instantaneous value current i (t), as shown in FIG. 6, once the i (t) is converted into the effective value I (t), the effective value is obtained. I (t) is rated current 1p. u. Monitor for exceeding. FIG. 7 shows a block diagram for calculating the effective value I (t) from the instantaneous value i (t) of the current. Using the instantaneous value i (t) and the instantaneous value i2 (t) whose phase is shifted by 90 degrees in electrical angle, the effective value I (t) is calculated by the following equation.
(Equation 1)
I (t) = √ (i (t) ^ 2 + i2 (t) ^ 2) / √2
If an accident occurs in the gas-insulated switchgear, the monitored current exceeds the rated current. If it exceeds, the process proceeds to the next process S2. If not, the process does not proceed to step S3.

  In the process S2, the waveform recording unit 5 records instantaneous waveforms of signals from the axial strain sensors 3a, 3b, 3c... And the axial strain sensors 4a, 4b, 4c.

  In the process S3, a gas section exceeding a predetermined threshold ε1 is specified from the axial strain sensors 3a, 3b, 3c. In the gas compartment where a ground fault has occurred due to an accident, the internal gas is overheated by the arc current and expands, so that distortion occurs in the axial direction and the circumferential direction of the gas compartment that is basically cylindrical. Therefore, by performing this process, it is possible to identify and narrow down the candidate gas compartment where the accident has occurred, and to reduce erroneous detection due to noise. Here, the accident means that a ground fault or a short circuit occurs due to foreign matter or outgassing.

  The axial strain σ1 will be described with reference to FIG. Here, it is assumed that a ground fault has occurred in the gas compartment 1b in FIG. In addition to the gas compartment 1b, the adjacent gas compartments 1a and 1c also exceed the threshold value ε1, so the gas compartments 1a, 1b, and 1c are selected among the many gas compartments, and accident points are candidates. It becomes. If the peak value does not exceed the threshold value, it is excluded from the candidates.

  If there is only one gas section that exceeds the threshold ε1, this is rated as an accident point, and the process proceeds to step S6. Further, when there are a plurality of gas sections exceeding the threshold ε1, the gas section having the maximum waveform peak value may be evaluated as an accident point, and the process may proceed to step S6.

  In the process S4, the ratio σ1 / σ2 between the circumferential strain σ1 and the axial strain σ2 is calculated for the gas section that has become the accident point candidate in the process S3. The circumferential strain σ2 is as shown in FIG. FIG. 8C shows an example of the calculation result of the ratio σ1 / σ2. The ratio of the gas section 1b where the accident has occurred is the largest.

  In process S5, the gas section 1b having the largest ratio σ1 / σ2 is evaluated as an accident point.

  In process S6, an accident occurs in the gas-insulated switchgear that is the object of diagnosis from information on the protective relay provided to operate the circuit breaker (FIG. 3) when an excessive current flows through the conductor 2. If it is determined that the occurrence of an accident is not specified by the protection relay information, the process returns to the process S1 and the evaluation is performed again.

  Next, in step S7, the evaluated gas section is displayed on the monitor screen of the processing unit 6. FIG. 5 shows a display example of the accident point on the monitor screen. The information of the gas compartment is added to the single-phase connection diagram shown in FIG. 3, and the correspondence with the gas compartment of the actual gas switchgear can be easily understood. Accident points are highlighted and can be seen at a glance. In addition, information on the accident phase is displayed in the lower right. In FIG. It is illustrated that an accident has occurred in the phase A of the portion corresponding to the gas compartment 022.

  In FIG. 9, the example of another accident point location which the process part 6 performs is shown. In the process of FIG. 9, the S1 process is omitted from the process of FIG. Since the current is not constantly monitored, the processing burden at the time of accident location can be reduced.

  According to the above embodiment, the accident point can be evaluated immediately after the accident occurs. As a result, significant labor savings can be expected. Furthermore, in this embodiment, since the insulating gas can be realized without removing the gas from the gas compartment, the risk of gas leakage is small, simple and highly reliable.

1a, 1b, 1c ... gas compartments,
2 ... conductor,
3a, 3b, 3c ... axial strain sensor,
4a, 4b, 4c ... circumferential strain sensors,
5 ... Waveform recording part,
6 ... processing part,
7 ... Ground fault,
8 ... Current sensor,
31a, 31b, 31 ... metal tube 32a, 32b ... spacer

Claims (7)

In an accident point rating device for a gas insulated switchgear having a plurality of gas compartments for storing conductors,
Strain detection means attached to each of the metal tubes constituting the gas compartment, and detecting strain of the metal tubes;
A processing means for evaluating a specific gas section as an accident point from among the gas sections in which the strain of the strain detection means exceeds a predetermined value;
Accident point rating device characterized by comprising In claim 1,
A recording device for recording the signal of the distortion detection means;
An accident point locating device, wherein the processing means locates the gas section having a maximum peak value in the waveform of a signal stored in the recording device as an accident point. In claim 1,
The strain detection means detects strain in the axial direction of the metal tube,
The accident point locating apparatus characterized in that the processing means locates a specific gas section as an accident point from the gas sections in which the axial distortion exceeds a predetermined value. In claim 1,
The strain detection means detects a circumferential strain and an axial strain of the metal tube,
The processing means determines the specific gas section as an accident point on the basis of the axial strain and the circumferential strain. In claim 4,
The processing means obtains a ratio of the circumferential strain to the axial strain, and locates the gas section having the maximum ratio as an accident point. In claim 5,
Current detecting means for detecting a current flowing through the conductor;
A blocking means for blocking the current of the conductor;
Based on the current detected by the current detection means, the protection means for operating the interruption means when an accident occurs,
An accident point locating device, wherein if the information from the protection means denies the occurrence of an accident, the processing means redoes the accident point evaluation process. In claim 6,
An accident point locating device comprising display means for displaying a gas section evaluated as an accident point.

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