JP2017083456A - Dew condensation detection method of switch gear - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a dew condensation detection method of a switch gear for detecting a dew condensation state of the switch gear during periodic inspection etc. to enable countermeasures for dew condensation.SOLUTION: A dew condensation detection device of a switch gear comprises: a sensor 1 having a pair of comb-shaped electrodes on a surface of an insulator; a power supply 2 for applying voltage to the sensor; and a leakage current detector 3 for detecting leakage current from the sensor 1. Leakage current characteristics to humidity of the sensor are preliminarily measured to define a surface resistivity showing prescribed leakage current, as a determination value, and the sensor 1 is arranged in the switch gear to detect leakage current from the leakage current detector 3 during an operation state of the switch gear. The detected leakage current is converted to a surface resistivity, and this surface resistivity is compared with the determination value to determine occurrence of a dew condensation state.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a switchgear dew condensation detection method for detecting dew condensation that causes insulation deterioration of an insulator.

  Insulation deterioration of an insulator in a metal closed switchgear that houses a switch that opens and closes the main bus and the electric circuit in a metal box, in addition to the deterioration over time of the material itself, also condensation on the surface of the insulator One of the factors. In particular, indoor switchgear generally does not include a space heater inside, and generally manages the temperature and humidity of the electrical room. However, depending on the electrical room, outside air is taken in, and the temperature and humidity in the electrical room change due to the influence of the outside air. There is also a switchgear, and condensation may occur when the back side of the switchgear is cooled.

When such condensation occurs, it is known that the surface of the insulator chemically changes and causes deterioration of insulation. By eliminating the external factor of insulation deterioration called condensation, a switch used for a long time The insulation performance of the gear can be maintained.
However, since the internal state of the switchgear cannot be grasped during operation, cleaning is performed at the time of periodic inspection.

On the other hand, the environment in which the switchgear is arranged varies, and the periodic inspection cycle varies. For this reason, it is important to immediately monitor the state change by monitoring the internal state of the switchgear.
For monitoring such an internal state of the switchgear, for example, as shown in Patent Document 1, a sensor for measuring the surface resistivity and a sensor for measuring the humidity are provided inside the switchgear, and the correlation between them is provided. Some have been proposed for diagnosing the lifetime of an insulator based on the relationship.

JP 2009-8427 A

  However, in the thing of such patent document 1, since the state in a board differs according to arrangement conditions, the power distribution equipment comprised by several surfaces differs from the sensor and humidity which measure surface resistivity to each switchgear of each board Therefore, there is a problem that an apparatus becomes expensive. In addition, there is a problem that replacement should be considered in terms of the life of the humidity sensor.

  This invention was made to solve the above problems, and provides a switchgear dew condensation detection method that detects the dew condensation state of the switchgear during periodic inspections and enables countermeasures thereof. The purpose is to reduce the price of the equipment.

  The dew condensation detection method for a switchgear according to the present invention includes a sensor provided with a pair of comb electrodes on the surface of an insulator, a power supply device that applies a voltage to the sensor, and a leakage current detection that detects a leakage current from the sensor. And measuring the leakage current characteristics with respect to the humidity of the sensor in advance to set a surface resistivity indicating a predetermined leakage current as a set judgment value, and placing the sensor inside the switchgear to operate the switchgear. The leakage current from the leakage current detection device in a state is detected and converted into a surface resistivity, and the occurrence of a dew condensation state is determined by comparison with the determination value.

  According to the present invention, when the switchgear needs to be inspected, a sensor composed of a pair of comb electrodes can be attached to detect the occurrence of the dew condensation state, the switchgear can be provided at a low cost, and the switchgear of the switchgear can be provided. It is possible to contribute to suppression of deterioration of insulation performance.

It is a block diagram which shows the dew condensation detection apparatus of the switchgear which is Embodiment 1 of this invention. It is a figure which shows the operating characteristic of the dew condensation detection apparatus of the switchgear in Embodiment 1 of this invention. It is a figure which shows the operation | movement flow of the dew condensation detection apparatus of the switchgear in Embodiment 1 of this invention. It is a figure explaining the operating characteristic of the dew condensation detection apparatus of the switchgear in Embodiment 2 of this invention. It is a figure explaining the operating characteristic of the dew condensation detection apparatus of the switchgear in Embodiment 3 of this invention. It is a figure explaining the operating characteristic of the dew condensation detection apparatus of the switchgear in Embodiment 3 of this invention.

Embodiment 1 FIG.
Hereinafter, the present invention will be described with reference to the drawings which are the first embodiment.
FIG. 1 is a configuration diagram showing a switchgear dew condensation detection device according to a first embodiment of the present invention. In the figure, a sensor 1 is formed by arranging a pair of comb-shaped electrodes facing each other on an insulator, and the sensor. 1 includes a power supply device 2 that supplies a current to 1 and a leakage current detector 3 that detects a leakage current from the current supplied to the sensor 1 and the output current and converts it to a surface resistivity.

Using the sensor 1 having such a configuration, first, the surface resistivity with respect to a change in humidity as shown in FIG. 2 is obtained, and from this result, for example, the surface resistivity in a high humidity state where the humidity is 80% is determined. When it is set as a value A (for example, 10 ⁸ Ω / □) and a surface resistivity smaller than the determination value A is determined, it is determined that a dew condensation state is present.

  Next, when the actual switchgear is periodically inspected, the sensor 1 is disposed therein, and as shown in FIG. 3, the sensor 1 is kept at a constant interval Δt (for example, every hour) for a predetermined period (for example, one day). A leakage current generated in the sensor 1 by applying a voltage from the power supply device 2 is measured by the leakage current detector 3 (step S1). This leakage current value is converted into the surface resistivity R and compared with the determination value A (step S2). If the surface resistivity R is larger, the measurement time of the state and the data of the surface resistivity R are recorded ( Step S3). If the measured surface resistivity R is smaller, the measurement time and the surface resistivity R at that time are output and displayed (step S4). In addition, data of measurement time and surface resistivity R is recorded. Thereafter, when the next measurement timing comes, measurement is repeated by repeating the above steps.

In this way, by outputting the measurement time and the surface resistivity R, dew condensation has occurred inside the switchgear even when monitoring is performed in a location different from the electrical room where the switchgear is installed. It is possible to grasp the necessity of measures such as improving the environment in the electric room.
Further, when it is detected that dew condensation has occurred, the setting environment of the switch gear is improved by changing the setting of the space heater inside the switch gear or adjusting the temperature or humidity of the electric chamber.
Thereafter, in the subsequent measurement, if the dew condensation state is not detected, it can be confirmed that the installation environment has been improved. If the surface resistivity R is further below the judgment value A, the switchgear is It can be determined that insulation deterioration has occurred, and the replacement of the device can be promoted.
As a result, the continuation of the dew condensation state inside the switch gear can be suppressed, so that the insulation deterioration of the switch gear can be suppressed and the occurrence of the insulation deterioration can be detected.

  After the determination of the surface resistivity R, the tendency of the surface resistivity R can be displayed or recorded on the screen by transmitting all the determination results to a monitoring device or a computer that is monitoring, Furthermore, by arranging the sensors 1 in all the switch gears, the degree of change in the surface resistivity R can be grasped in one array or in the entire electric chamber, and dew condensation in all the switch gears can be detected.

Embodiment 2. FIG.
By the way, the switchgear that performs periodic inspection may have passed several years or several decades since installation. On the other hand, since the sensor 1 is new, the surface resistivity R of the insulator in the sensor 1 is obtained. Even so, the surface resistivity R of the new insulator is obtained, and the surface resistivity R of the insulator in the existing switchgear is not obtained, so that dew condensation cannot be detected. .

  In order to cope with such a difference in the surface resistivity R, first, the existing switchgear is held in a stopped state, and the surface resistivity RR of the insulator in this state is measured. As shown in FIG. The surface resistivity obtained from 1 is replaced with the surface resistivity RR of the existing panel, and then the leakage current value of the sensor 1 attached to this switchgear is measured with the existing switchgear in the operating state, and this is the surface resistivity. When the value falls below the judgment value A in terms of, it is judged that there is a dew condensation state. Thus, by obtaining the surface resistivity of the switch gear in the stopped state and taking the measured value of the sensor 1 into consideration, it is possible to detect the dew condensation state due to deterioration over time.

Embodiment 3 FIG.
In the second embodiment, the surface resistivity is replaced with the surface resistivity RR of the existing switchgear so that the dew condensation state on the existing panel is detected. However, the insulation in the sensor 1 is deteriorated and measured. Even if it is made to do, it can be made to carry out similarly. That is, the surface of the sensor 1 made of an insulator provided with comb-shaped electrodes is deteriorated in advance with nitric acid or the like, and the relationship between the exposure time with nitric acid and the surface resistivity is obtained as shown in FIG.

  Next, the existing switchgear is held in a stopped state, the surface resistivity RR in this state is measured, and the nitric acid exposure time at which the surface resistivity is the same as the surface resistivity RR is obtained to determine the insulator of the sensor 1 Exposure to deteriorate the surface. Thereafter, the deteriorated sensor 1 is installed in the existing switchgear, the leakage current by the sensor 1 is measured with the switchgear in the operating state, and the converted surface resistivity is compared with the determination value A. With this configuration, when the value falls below the determination value A as shown in FIG.

As described above, according to the present invention, the dew condensation state in the switch gear can be detected with a simple configuration, and by displaying this, measures such as improvement of the installation environment can be promoted, and as a result, insulation deterioration can be suppressed. Is possible.
In the present invention, each embodiment can be appropriately modified or omitted within the scope of the invention.

1: Sensor 2: Power supply 3: Leakage current detector

The dew condensation detection method for a switchgear according to the present invention includes a sensor provided with a pair of comb electrodes on the surface of an insulator, a power supply device that applies a voltage to the sensor, and a leakage current detection that detects a leakage current from the sensor. Device and means for determining the occurrence of condensation based on the output of the leakage current detection device, and measuring the leakage current characteristics with respect to the humidity of the sensor in advance and setting the surface resistivity indicating the predetermined leakage current as the determination value The sensor is arranged inside the switchgear, the leakage current from the sensor when the switchgear is stopped is detected by the leakage current detector and converted into the surface resistivity, and the converted surface resistivity is is replaced with the initial value of the surface resistivity of the sensor, the leakage current from the sensor in the leakage current detection device in the operating state of the switch gear Detected and converted into surface resistivity in consideration of the initial value, the measurement value is obtained so as to determined to be in condensation state by said determining means when lower than the determination value.

Claims (4)

  A sensor provided with a pair of comb-shaped electrodes on the surface of an insulator; a power supply device that applies a voltage to the sensor; and a leakage current detection device that detects a leakage current from the sensor. Measure the current characteristics, set the surface resistivity indicating the predetermined leakage current as the judgment value, and place the sensor inside the switchgear to detect the leakage current from the leakage current detector in the switchgear operating state Then, it is converted into surface resistivity and compared with the determination value to determine the occurrence of the dew condensation state, and the switch gear dew condensation detection method is characterized.   2. The detection of dew condensation in a switchgear according to claim 1, wherein when the surface resistivity in the operating state of the switchgear falls below the judgment value, an output is generated to indicate that a dew condensation state has occurred. Method.   The surface resistivity in the stop state of the switchgear is obtained, the initial value of the surface resistivity of the sensor is replaced with the surface resistivity, and the surface resistivity in the operation state of the switchgear is measured. 3. The method for detecting dew condensation in a switchgear according to claim 1 or 2, wherein the occurrence of dew condensation is determined when the value is less than.   The surface resistivity of the switchgear when it is stopped is acquired, the surface of the sensor is deteriorated to the same surface resistivity as that of the switchgear, and the sensor is placed on the switchgear to operate the switchgear. 3. The switchgear dew condensation detection method according to claim 1, wherein the surface resistivity is measured and the occurrence of dew condensation is determined when the measured value falls below the determination value.

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