JP5269052B2 - Switchgear, switchgear insulation performance evaluation method, and insulation resistance test piece - Google Patents

Description

  The present invention relates to a switchgear, a performance evaluation method for an insulator of a switchgear, and a test piece for measuring insulation resistance.

  In switchgear that houses main busbars, devices such as circuit breakers and lightning arresters connected to the main busbars, cables connected to these circuit breakers, etc. in a metal housing, the compartment is partitioned by a metal partition A main bus, a circuit breaker, a lightning arrester, a cable and the like are accommodated in the housing, and are attached to the partition wall by a support insulator in order to insulate the main bus from the support. In such a switchgear, the insulation resistance of the support insulator is reliably measured by making the switchgear in a power failure state by, for example, opening the accommodated circuit breaker. (For example, see Patent Document 1)

JP 2007-274861 A

  By the way, as a factor that decreases the insulation resistance of an insulator such as a support insulator of the switch gear, the ambient relative humidity at the time of measurement can be cited in addition to the deterioration of the insulator. For this reason, when the ambient relative humidity is high and the insulation resistance is low, it cannot be determined whether the cause of the decrease in the insulation resistance is the influence of the deterioration of the insulator or the influence of the surrounding relative humidity. Therefore, the measurement of insulation resistance temporarily performed at the time of inspection cannot accurately determine the quality of an insulator or grasp the tendency of deterioration.

  In addition, the insulation resistance measurement at the time of inspection is performed by removing the partition plate, etc. inside the switchgear. However, in the actual operation state, the insulation is closed by a partition wall, etc. The state around the object is different from the state during operation. For this reason, in the measurement of the insulation resistance performed at the time of inspection, it is not possible to evaluate the performance of an appropriate insulator in accordance with the actual operation state.

  Also, since insulation resistance cannot be measured during operation, if insulation resistance decreases due to environmental factors surrounding the insulation inside the switchgear, it cannot be detected, and the insulation remains normal. I can't figure out if it's done.

  This invention is made | formed in view of the said situation, and makes it a subject to improve the reliability of evaluation of the insulation performance of the insulator installed in the switchgear inside.

In order to solve the above-mentioned problems, a switchgear according to the present invention is provided with a compartment partitioned by a partition wall in an internal space in which a busbar and a device connected to the busbar are accommodated, and an insulator in the compartment A test piece for measuring insulation resistance, which is provided in the compartment so as to be connected to an insulation performance management device having an insulation resistance measurement function, and made of the same material as the insulator. And a humidity detector that detects the relative humidity of the compartment, relational data indicating the relationship between the relative humidity detected by the humidity detector and the insulation resistance of the test piece measured by the insulation performance management device And a determination unit for determining the insulation performance of the insulator based on the relation data recorded in the recording unit, the determination unit being obtained from the relation data, Characteristics of humidity-insulation resistance Slope of the curve you determine whether or not the normal range.

  The switch gear may include an alarm unit that warns when the determination result of the determination unit is negative.

In order to solve the above-described problems, the method for evaluating the performance of a switchgear insulator according to the present invention is provided with a compartment partitioned by a partition wall in an internal space in which a busbar and a device connected to the busbar are accommodated. A switchgear in which an insulator is installed in the compartment, a method for evaluating the insulation performance of the insulator in the compartment, and a test piece for measuring insulation resistance made of the same material as the insulator, Installed in the compartment and connected to an insulation performance management device having an insulation resistance measurement function, and the relative humidity of the compartment is detected by a humidity detector, and the insulation resistance of the test piece is determined by the insulation performance management device. Measure and record the relationship data indicating the relationship between the relative humidity detected by the humidity detector and the insulation resistance of the test piece measured by the insulation performance management device, and obtain from the recorded relationship data is, relative humidity - the insulation resistance characteristic It determines whether the slope of the line is in the normal range.

  ADVANTAGE OF THE INVENTION According to this invention, the reliability of evaluation of the insulation performance of the insulator installed in the switchgear can be improved.

It is a figure which shows schematic structure of the switchgear which concerns on one Embodiment. It is a figure which shows the electrode which expands a test piece and measures insulation resistance. It is a block diagram which shows schematic structure of an insulation performance management apparatus. It is a graph which shows the characteristic curve of the relative humidity-insulation resistance of the soiled object. (A) is a graph showing a characteristic curve of relative humidity-surface resistivity of an insulator that has not deteriorated immediately after the start of use, and (B) is an insulation that has deteriorated significantly after a long period of time has elapsed since the start of use. It is a graph which shows the characteristic curve of the relative humidity-surface resistivity of an object.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. FIG. 1 is a side sectional view showing a schematic configuration of a switchgear 10 according to an embodiment. As shown in this figure, the switchgear 10 includes a grounded metal casing 50, an upper duct 22 disposed on the top plate of the casing 50, and a main bus 12 installed in the casing 50. , A bus bar 13, a lightning arrester 14, a circuit breaker 16, a power cable 18 and a control panel 20. The main bus 12 connects the lightning arrester 14 and the circuit breaker 16, and the bus 13 connects the circuit breaker 16 and the power cable 18. The control panel 20 is provided with a protective relay and the like.

  Opening / closing doors 57 and 58 are respectively provided on the front surface on the left side of the housing 50 in the drawing and the rear surface on the right side in the drawing. The inside of the housing 50 is partitioned by a metallic partition wall 52 into a compartment 50F on the left side of the control panel 20 in the drawing and a compartment 50R on the right side in the drawing. Further, the compartment 50R on the device side of the housing 50 is cut off by a metal partition wall 54 in which a main bus room 50A for storing the main bus bar 12, a lightning arrester room 50B for storing the lightning arrester 14, and a circuit breaker 16 are stored. It is partitioned into a chamber 50C, a bus 13 connected to the device, and a cable chamber 50D for storing the power cable 18.

  The cable room 50D is arranged on the control panel 20 side (left side in the figure), and on the opposite side (right side in the figure), a lightning arrester room 50B and a circuit breaker room 50C are arranged one above the other. A bus bar room 50A is arranged. In addition, a part (lower part) of the partition wall 54 that partitions the main bus room 50A and the cable room 50D is opened, and is partitioned by an insulating (non-metallic) partition plate 56.

  Vents 57A and 58A are provided at the lower portions of the opening and closing doors 57 and 58, respectively. The upper duct 22 is provided with vent holes 22A and 22B on the front side and the rear side, respectively, and a ventilation fan 24 is provided facing the vent hole 22A. Further, the top plate 23 and the partition walls 52 and 54 of the housing 50 are provided with vent holes, and when the ventilation fan 24 is operated, the air in each compartment such as the main bus room 50A in the housing 50 is supplied. Ventilated.

  Here, in the main bus chamber 50A, the main bus 12 is supported by a metal partition wall 54 via a support insulator 26 that is an insulator. Also, a humidity detector 28 and a test piece 30 for measuring insulation resistance are installed in the main bus room 50A. An insulation performance management device 40 is installed in the compartment 50F on the control panel 20 side in the housing 50. The insulation performance management device 40 is connected to the humidity detector 28 and the test piece 30 by a coaxial cable 32 such as an X-ray cable. The humidity detector 28 detects the relative humidity in the main bus room 50 </ b> A and outputs it to the insulation performance management device 40.

  FIG. 2 is a diagram showing an electrode 34 for measuring the insulation resistance by enlarging the test piece 30. As shown in this figure, the test piece 30 is provided with a pair of electrodes 34, and the terminals of the coaxial cable 32 are fixed to the electrodes 34. Here, the test piece 30 is an insulator formed of the same material as the support insulator 26 and having the same shape as the support insulator 26.

  FIG. 3 is a block diagram showing a schematic configuration of the insulation performance management device 40. As shown in this figure, the insulation performance management device 40 includes an insulation resistance measuring device 42 that measures the insulation resistance of the test piece 30 and an alarm device 44 that warns when the insulation performance evaluation of the support insulator 26 is outside the normal range. And a control device 46 that controls the insulation resistance measuring device 42 and the alarm device 44.

  The control device 46 includes a recording measurement control unit 46A, a recording unit 46B, a determination unit 46C, and an alarm control unit 46D. When the relative humidity detected by the humidity detector 28 reaches a predetermined relative humidity value, the recording measurement control unit 46A controls the insulation resistance measuring device 42 to measure the insulation resistance. At this time, the recording measurement control unit 46A detects the humidity. Collect relative humidity. The recording unit 46B controls the recording measurement control unit 46A and records the insulation resistance measured by the insulation resistance measuring device 42 and the relative humidity detected by the humidity detector 28 in association with each other. The determination unit 46C determines whether the insulating performance of the support insulator 26 is good or bad. When the determination result is negative, the determination unit 46C controls the alarm control unit 46D and the alarm device 44 issues an alarm.

  By the humidity detector 28, a first predetermined relative humidity value (a predetermined lower limit value, for example, 70% RH) and second to fourth predetermined humidity values higher than the first predetermined relative humidity value. When any of the relative humidity values (values increasing by 10% RH, for example, 80% RH, 90% RH, 100% RH) is detected, the recording measurement control unit 46A causes the insulation resistance measuring device 42 to Outputs a measurement instruction signal.

  When receiving the measurement instruction signal from the recording measurement control unit 46A, the insulation resistance measuring instrument 42 starts measuring the insulation resistance of the test piece 30 and outputs the measurement value to the recording measurement control unit 46A. When the measurement value is input from the insulation resistance measuring device 42, the recording measurement control unit 46A records the measurement value in the recording unit 46B together with the relative humidity detected by the humidity detector 28. Here, when a plurality of relative humidity values (for example, 70% RH and 80% RH) are detected by the humidity detector 28, a characteristic curve of relative humidity-insulation resistance is created. When the relative humidity of the same value is detected again, the insulation resistance is measured again, and the insulation resistance corresponding to the relative humidity recorded in the recording unit 46B is updated.

  The determination unit 46C determines whether the slope of the created characteristic curve of relative humidity-insulation resistance (ratio of the decrease amount of the insulation resistance value with respect to the increase amount of the relative humidity value) is within the normal range. When it is outside, a determination signal is output to the alarm control unit 46D. When the alarm control unit 46D receives the determination signal from the determination unit 46C, the alarm control unit 46D outputs an alarm instruction signal to the alarm device 44, whereby the alarm device 44 issues an alarm.

  By the way, when the surface of an insulator such as the support insulator 26 is fouled by adhering fouling substances and the humidity around the insulator rises due to weather conditions, the insulation resistance of the insulators rapidly decreases. When a voltage is applied to the insulator in this state, a leakage current flows intermittently and a minute discharge current is generated.

  Here, when the applied voltage is low, the Joule heat of the leakage current causes the water to evaporate uniformly over the entire surface of the insulator, and the entire surface is uniformly dried. However, when the applied voltage is high, a local dry band (dryness) is formed, and a minute discharge (scintillation or the like) occurs due to the voltage being concentrated on the dry band. As a result, depending on the insulating material, a tracking phenomenon, that is, a part of the insulating material is thermally decomposed by discharge, and carbon is liberated to form a carbonized conductive path, thereby causing a phenomenon of dielectric breakdown peculiar to organic insulating materials. .

FIG. 4 is a graph showing a characteristic curve of relative humidity-insulation resistance of a soiled insulator. In order to obtain the characteristic curve, the characteristic curve of this graph has a degree of fouling of 0.03 mg / cm ² (the amount of sodium chloride attached per unit area) on the surface of a 10 mm × 10 mm × 70 mm rectangular parallelepiped test piece. Is a characteristic curve of an experimental example in the case where the fouling liquid of (1) is applied after spraying and then dried, and the humidity is changed in a constant temperature / humidity tank at a constant temperature (40 ° C.).

  As shown in the graph of FIG. 4, when the relative humidity increases exceeding 70% RH, the insulation resistance rapidly decreases. Such a phenomenon occurs because when the relative humidity exceeds 70% RH, the salinity in the dried fouling liquid causes deliquescence. For this reason, when the degree of contamination of the insulator is low, it is said that the insulation resistance does not rapidly decrease until the relative humidity exceeds 85% RH, whereas an insulator with a high degree of contamination is treated with high humidity. When used in an environment, when the relative humidity exceeds 70% RH, the leakage current increases and the decrease in insulation resistance accelerates rapidly.

  FIG. 5A is a graph showing a characteristic curve of relative humidity-surface resistivity of an insulator that has not deteriorated immediately after the start of use. FIG. 5B is a graph showing a relative humidity-surface resistivity characteristic curve of an insulator that has deteriorated significantly after a long period of time has elapsed since the start of use. As shown in the graph of FIG. 5A, when the insulator is not deteriorated immediately after the start of use, the degree of decrease in surface resistivity (insulation resistance) due to increase in relative humidity is small. On the other hand, as shown in the graph of FIG. 5 (B), the degree of decrease in the surface resistivity (insulation resistance) due to the increase in relative humidity increases remarkably as a long period of time elapses from the start of use and the deterioration of the insulator becomes significant. .

  In view of the above, it is necessary to grasp the correlation between the insulation resistance of the support lever 26 and the surrounding relative humidity during the operation of the switchgear 10, and to grasp the tendency of deterioration of the support lever 26 based on the correlation. However, in order to directly increase the insulation resistance of the support insulator 26, the switchgear 10 needs to be in a power failure state.

  Therefore, in the present embodiment, a test piece 30 having the same shape and the same material as that of the support insulator 26 is installed in the main bus chamber 50A in which the support insulator 26 is installed, and the insulation resistance of the test piece 30 is measured. . That is, the insulation resistance of the test piece 30 is used as a substitute value for the insulation resistance of the support insulator 26. Further, the humidity detector 28 detects the relative humidity in the main bus room 50A. Then, by recording the measured insulation resistance of the test piece 30 and the relative humidity in the main bus room 50A at the time of measuring the insulation resistance, the insulation resistance of the test piece 30 and the relative humidity in the main bus room 50A are recorded. “Insulation resistance-relative humidity characteristic curve” is created. And the quality determination of the insulation performance of the support insulator 26 is performed based on the created characteristic curve.

  As described above, according to the switchgear 10 according to the present embodiment, when the relative humidity in the main bus chamber 50A is high and the insulation resistance of the support insulator 26 is low, the cause of the decrease in the insulation resistance is the deterioration of the insulator. Or the influence of the relative humidity of the surroundings. Therefore, unlike the measurement of the insulation resistance temporarily performed at the time of inspection, it is possible to accurately determine the quality of the insulation performance of the support insulator 26 and to grasp the tendency of deterioration.

  In addition, the insulation resistance of the test piece 30 that is the same insulator as the support insulator 26 and in the same environment can be measured in a state in which the periphery of the support insulator 26 is closed by the partition wall 54 or the like, that is, in an operating state. . Therefore, unlike the measurement of the insulation resistance performed at the time of inspection, it is possible to evaluate the insulation performance of the support insulator 26 appropriate to the actual operation state.

  In addition, since the insulation resistance of the test piece 30 that is the same insulator as the support insulator 26 during operation and is in the same environment can be measured, the environmental factors around the support insulator 26 in the switchgear 10 cause the support insulator 26 to When insulation resistance falls, it can be detected and it can grasp | ascertain whether the support insulator 26 has maintained the normal state.

  Therefore, according to the switch gear 10 according to the present embodiment, the reliability of the performance evaluation of the support lever 26 in the switch gear 10 can be improved.

  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. For example, in the above embodiment, the present invention has been described by taking the support insulator 26 installed in the main bus room 50A as an insulator for evaluating the insulation performance, but the lightning arrester room 50B, the circuit breaker room 50C, and the like. The present invention may be applied to evaluate the insulation performance of the insulators installed in other compartments.

  In the present embodiment, the humidity detector 28 is installed in the compartment of the switchgear 10 to detect the relative humidity in the compartment, and the insulation performance of the support insulator 26 is evaluated based on the detected value. However, even if the relative humidity outside the compartment or the outside of the switchgear 10 is detected and the detected value is used as a substitute value for the relative humidity inside the compartment in which the insulator is installed, the insulation performance of the support insulator 26 is evaluated. Good.

DESCRIPTION OF SYMBOLS 10 Switch gear 12 Main bus line 13 Bus line 14 Lightning arrester 16 Circuit breaker 18 Power cable 20 Control panel 22 Upper duct 22A, 22B Exhaust port 23 Top plate 24 Ventilation fan 26 Support insulator (insulator)
28 Humidity detector 30 Test piece 32 Coaxial cable 34 Electrode 40 Insulation performance management device 42 Insulation resistance measuring device 44 Alarm (alarm unit)
46 control device 46A recording measurement control unit 46B recording unit 46C determination unit 46D alarm control unit 50 housing 50A main bus room (partition room)
50B Lightning Arrestor Room 50C Breaker Room 50D Cable Room 50F, 50R Partition 52, 54 Partition 56 Partition Plate 57, 58 Opening Door 57A, 58A Vent

Claims (3)

A switchgear in which a compartment partitioned by a partition wall is provided in an internal space in which a busbar and a device connected to the busbar are stored, and an insulator is installed in the compartment,
A test piece for measuring insulation resistance, which is provided in the compartment so as to be connected to an insulation performance management device having an insulation resistance measurement function, and made of the same material as the insulator ;
A humidity detector for detecting the relative humidity of the compartment;
A recording unit that records relationship data indicating a relationship between the relative humidity detected by the humidity detector and the insulation resistance of the test piece measured by the insulation performance management device;
A determination unit for determining the insulation performance of the insulator based on the relation data recorded in the recording unit;
Equipped with a,
The determination unit is determined from the relationship data, relative humidity - switchgear you determine whether the slope of the characteristic curve of the insulation resistance is normal range. The switchgear according to claim 1 , further comprising an alarm unit that warns when the determination result of the determination unit is negative. Insulation of the insulation of the switchgear of the switchgear in which a compartment partitioned by a partition wall is provided in an internal space in which a busbar and a device connected to the busbar are stored, and an insulator is installed in the compartment A method for evaluating performance,
A test piece for measuring insulation resistance made of the same material as the insulator is installed in the compartment and connected to an insulation performance management device having an insulation resistance measurement function.
While detecting the relative humidity of the compartment with a humidity detector, the insulation performance management device measures the insulation resistance of the test piece,
Record the relationship data indicating the relationship between the relative humidity detected by the humidity detector and the insulation resistance of the test piece measured by the insulation performance management device,
A method for evaluating the performance of an insulator of a switchgear that determines whether or not the slope of a characteristic curve of relative humidity-insulation resistance obtained from the recorded relational data is within a normal range .

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