JP2019068009A - Management and maintenance method of on-load tap changer - Google Patents

Abstract

To provide a maintenance control method for preventing insulation performance of insulating oil and sealing performance of a diaphragm from being adversely affected by a gas generated from a switch in a sealed on-load tap changer with a diaphragm conservator.SOLUTION: When manufacturing an on-load tap changer 1, by filling insulating oil subjected to a degassing treatment to a total of oxygen and nitrogen gas concentrations of 20,000 [ppm] or less in a switch 2, gas generated by switching operation of the switch 2 is dissolved in an insulating oil 7 with a margin. Although the gas concentration in the insulating oil 7 increases with use over time, degassing is performed again in the insulating oil 7 before the gas bubbles.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a management and maintenance method for maintaining the insulation performance of insulating oil with which the on-load tap changer is filled.

  A transformer having a structure in which insulating oil filled in the container of the on-load tap switching device connected to the oil expansion chamber is prevented from coming into contact with air by a bag body (rubber bag) in the oil expansion chamber (conservator) Are conventionally known (see Patent Document 1 below).

Patent No. 5209581 JP 2015-115397

  As in the transformer described in Patent Document 1, by filling vegetable oil such as rapeseed oil as insulation oil in the container of the on-load tap changer, contributing to reduction of environmental load tends to increase in recent years .

  Further, the transformer described in Patent Document 1 adopts a vacuum valve type contact as a switching switch of the on-load tap switching device, and the arc at the time of the contact switching of the device generates sludge and contaminates the vegetable oil. It also has a feature that can prevent

  However, since the on-load tap changer generates a cracked gas in the insulating oil by the tap switching operation of the switch, the cracked gas needs to be released from the consor to the outside through the hygroscopic ventilator. Therefore, it is usual that the consorbeta is configured in a so-called open type without providing a rubber film or a rubber bag (see Patent Document 2 above).

  This is the same as when using vegetable oil as the insulating oil. Further, when a vacuum valve type contact is adopted as the switching switch, decomposition gas by the arc at the time of contact switching does not occur, but decomposition gas by the tap switching operation occurs. When the insulating oil is sealed with a rubber bag (or a rubber film) as in Patent Document 1 above, the gas in the insulating oil increases and bubbles, which may affect the insulating performance of the insulating oil, or may increase the consumption of the conditioner oil. May affect the sealing performance of the rubber film and the rubber bag.

  Therefore, in the present invention, in order to solve the above-mentioned problems, the gas generated by the tap switching operation of the switching switch is also the insulating performance of the insulating oil and the rubber bag (rubber film) even in the load type tap switching device of sealed type. We present management and maintenance methods that do not affect the sealing performance of the

  According to the first aspect of the present invention, the insulating oil degassed to have a total gas concentration of oxygen and nitrogen equal to or less than 20,000 [ppm] is sealed in a container of the switching switch, When flammable gas such as hydrogen or ethane or carbon dioxide is generated along with the switching of the tap, timing before gas such as hydrogen, oxygen or nitrogen having low solubility in the insulating oil is bubbled, By deaerating the insulating oil again, the insulating oil is characterized in that the insulating performance of the insulating oil and the sealing performance of the rubber bag (rubber film) are prevented from being disturbed.

  The invention according to claim 2 relates to the timing according to claim 1 in that the hydrogen concentration in the insulating oil is 20,000 ppm, or the oxygen concentration is 30,000 ppm, or the nitrogen concentration is 60,000 ppm It is characterized in that it is a point in time before reaching any one of.

  The invention according to claim 3 is characterized in that the timing according to claim 1 is when the number of times of operation of the on-load tap change switch has reached 100,000 times and a multiple thereof.

  The invention according to claim 4 is characterized in that the timing according to claim 1 is 10 years after the start of operation of the on-load tap change switch, and a multiple year thereof.

  The invention according to claim 5 is characterized in that the insulating oil according to any of claims 1 to 4 is a vegetable oil.

  According to the first aspect of the present invention, the degassing treatment of the insulating oil is carried out by degassing so that the total gas concentration of oxygen and nitrogen in the insulating oil is 20,000 ppm or less, and the container is sealed in the switchgear container. By doing this, flammable gas and carbon dioxide generated with the tap switching of the on-load tap change switch can be dissolved with a margin.

  In addition, even if the gas concentration in the insulating oil rises, the insulating oil is deaerated again at the timing before the low solubility gas bubbles, so the insulating performance of the insulating oil and the sealing of the rubber bag or rubber film It is possible to prevent the performance from being impaired.

  According to the second aspect of the present invention, it is possible to clarify the timing before the gas having a low solubility in the insulating oil is bubbled, and to improve the accuracy of maintenance management.

  According to the third aspect of the present invention, it is possible to clarify the timing before the gas having low solubility in the insulating oil is bubbled, as the number of operations of the switchgear which can be easily grasped by the person in charge of maintenance management. .

  According to the fourth aspect of the present invention, it is possible to clarify the timing before the gas having low solubility in the insulating oil is bubbled as the operating years of the switchgear which can be easily grasped by the person in charge of maintenance management. .

  According to the fifth aspect of the invention, the use of the vegetable oil as the insulating oil can contribute to the reduction of the environmental load.

It is a front view of an on-load tap changer concerning one embodiment of the present invention. It is a figure which shows the combustible gas increase by progress of the number of years of operation.

  FIG. 1 is an enlarged view of the on-load tap changer 1 attached to the transformer. In FIG. 1, reference numeral 2 denotes a switching switch unit constituting the on-load tap switching device 1 attached to the transformer tank 3, and reference numeral 4 denotes a tap selector.

  Reference numeral 2a denotes a switching switch body housed in the container 2b of the switching switch unit 2. The switching switch body 2a employs a vacuum valve type contact (not shown) as a contact for tap switching.

  Reference numeral 5 denotes a consorter connected to the on-load tap switching device 1 via the communication pipe 6, and 7 denotes insulation filled in the container 2b of the switching switch section 2 via the communication pipe 6 from inside the container 2b. It is oil. As the insulating oil 7, a vegetable oil such as palm fatty acid ester oil or the like or a viscosity lower than that of a mineral oil may be used.

  5a is a diaphragm (rubber film) for preventing the insulating oil 7 from coming into contact with the air in the conditioner 5, and 8 is a hygroscopic ventilator (breather) connected to the conditioner 5 via a breathing tube 9. .

  When vegetable oil is used as the insulating oil, palm oil fatty acid ester is suitable as the vegetable oil, but it is not limited to this, and vegetable oil based insulating oil having the same or lower kinematic viscosity as mineral oil based insulating oil It can also be used. Moreover, if such conditions are satisfied, it is also possible to use a mixture of mineral oil and vegetable oil.

  The on-load tap switching device 1 is electrically connected to a transformer main body (not shown) housed in the transformer tank 3.

  When a vegetable oil is used as the insulating oil for the switching switch unit 2, the on-load tap switching device 1 having the above-described configuration has little influence on the environment even if an oil leakage accident occurs. In addition, if palm oil fatty acid ester oil having a viscosity lower than that of rapeseed oil or the like is used as a vegetable oil, the performance of the switchgear 2 will not be impaired.

  The insulating oil is isolated from the air by the diaphragm 5a in the conservator 5, and does not oxidatively deteriorate without the addition of an antioxidant, and if it is a vegetable oil which is easily biodegradable even if it leaks oil, It has the advantage of low environmental impact.

  When the temperature of the insulating oil in the container 2b rises / falls along with the switching operation of the switching switch main body 2a, the insulating oil changes its volume according to the temperature change, but the volume change of the insulating oil is It is suitably absorbed by the diaphragm 5b in the reference numeral 5. By the absorbing action of the diaphragm, the air in the conditioner 5 is released / sucked to the outside through the breathing tube 9 and the hygroscopic ventilator 8.

  The switching switch unit 2 adopts a vacuum valve type as a contact for tap switching during load, and the contact portion is not in contact with the insulating oil, so sludge generated by arc at the time of contact switching is insulated It does not cause oil stains.

  However, even in the vacuum valve type on-load tap changer, gas (combustible gas such as hydrogen or ethane or carbon dioxide) is generated by the tap switching operation. The gas generation amount per one vacuum valve type tap switching operation varies depending on specifications and operating conditions, and is, for example, 0.01 to 0.1 [ppm].

  FIG. 2 is a graph showing the increase in combustible gas (the most frequently generated case and the least frequently generated case).

  In the open type described in the prior art, gas can be released from the insulating oil surface in the conservator through the breather (hygroscopic ventilator), but in the sealed type on-load tap changer, it is in the conservator 5 The gas can not be released to the outside by the diaphragm 5a.

  The generated gas is dissolved in the insulating oil, and when the gas concentration in the insulating oil is increased, hydrogen, oxygen and nitrogen having low solubility are bubbled in the insulating oil. There is a possibility that the insulating performance of the insulating oil may be impaired or the sealing performance of the diaphragm 5a may be impaired by the gas bubble formation.

  Therefore, in the present invention, the insulating oil to be filled in the on-load tap switching device 1 is deaerated in advance. As the degassing level, the gas concentration in the insulating oil is set to 20,000 ppm or less, more preferably 10,000 ppm or less, in total of the concentration of oxygen and nitrogen.

  That is, assuming that the gas in the insulating oil increases with the operation of the switching switch body 2a, hydrogen and oxygen having a low solubility in the insulating oil at the time of manufacture of the on-load tap switching device 1 Allow room for nitrogen not to bubble.

  Further, when gas is stored in the insulating oil 7 due to the use of the device 1 over time, the degassing process is performed again. The hydrogen concentration in the insulating oil reaches 20,000 ppm, or the oxygen concentration reaches 30,000 ppm, or the nitrogen concentration reaches any one of 60,000 ppm as the degassing treatment timing. It is taken as the previous point.

  The saturated solubility of carbon dioxide in palm fatty acid ester oil assumed by the present invention is 1,000,000 [ppm], but individual gases can not be dissolved to individual saturated solubility in insulating oil, and the amount that can be dissolved is limited There is. For this reason, the gas concentration serving as the above-mentioned judgment standard was set in order to allow room for the saturation solubility of each gas.

  After the degassing process is performed according to the determination criteria, the degassing process is performed again when the determination criteria are reached, and thereafter, the same maintenance management is repeatedly performed.

  The timing may be when the number of switching operations of the switching switch body 2a reaches a specified number, for example, when it reaches 100,000 times. Degassing is performed when it reaches 100,000 times, and the same maintenance management is repeatedly executed thereafter.

  Although 100,000 times as the prescribed number of times is the optimum timing, the number of times shorter or longer than this may be set depending on the characteristics of the device, the load, and the like.

  Although the amount of gas generation per vacuum valve type tap switching operation varies depending on the specifications and operating conditions, for example, assuming that it is 0.01 to 0.1 [ppm], the switching operation reached 200,000 times The amount of gas generated is also 2,000 to 20,000 ppm even at the time point. Incidentally, when a vegetable oil is used as the insulating oil, the saturated solubility of carbon dioxide of a typical cracked gas of palm fatty acid ester oil assumed by the present invention is 1,000,000 [ppm].

  Still another timing may be ten years after the start of operation of the switching switch. Even if the diaphragm 5a having sealing performance is adopted, oxygen and nitrogen in the air are gradually dissolved in the insulating oil via the diaphragm 5a, and the concentration is increased. Although depending on the installation environment and load, it is generally after 20 to 30 years that the concentration of oxygen and nitrogen in the insulating oil reaches the bubble formation. By performing the degassing process 10 years before the concentration of oxygen or nitrogen increases, it is possible to ensure that the on-load tap changer is not disturbed.

  Therefore, the degassing process is performed once 10 years after the start of the operation, and the degassing process is performed again after 10 years. The degassing process is similarly performed when the multiple year of 10 years is reached similarly.

  Although 10 years as the standard year and its multiple years are optimum timings, a short period or a long period may be set according to the characteristics and load of the device.

  Even if the insulating oil (vegetable oil) is sealed with a diaphragm by maintenance (degassing treatment) at the above timing, hydrogen, oxygen and nitrogen in the insulating oil are bubbled to cause various adverse effects. It can prevent.

  In the above-mentioned embodiment, although the case where diaphragm 5a was provided in consorbeta 5 was explained, it is natural that it is applicable also to the case where a rubber bag is provided. Further, the technology of the present invention is of course not limited to the on-load tap changer, and can be applied to general electrical appliances sealed with insulating oil.

  As described above, according to the maintenance management method of the present invention, in the load-time tap switching device configured in a sealed type, the gas generated by the tap switching operation of the switching switch and dissolved in the insulating oil (vegetable oil) Since it is possible to prevent the formation of bubbles, it is possible to reliably prevent the adverse effect on the insulation performance of the insulating oil (vegetable oil) or the hindrance to the sealing performance of the diaphragm.

  It can be used for various electrical devices sealed with insulating oil.

1, 10 Load tap switching device 2 Switching switch part 2a Switching switch body 2b Container of switching switch 3 Transformer tank 4 Tap selector 5 Conservator 5a Diaphragm (rubber film)
6 connecting pipe 7 insulating oil (vegetable oil)
8 hygroscopic ventilator 9 respiratory tube

Claims (5)

  Insulating oil degassed to a total of oxygen and nitrogen gas concentration of 20,000 [ppm] or less is sealed in the container of the switchgear, and flammable due to the switching of the tap of the vacuum valve switchgear. When a gas or carbon dioxide is generated, the insulating oil is deaerated again at a timing before the gas having a low solubility in the insulating oil is bubbled. Management of the on-load tap switching device Maintenance method.   The timing is the time before the hydrogen concentration in the insulating oil reaches 20,000 [ppm], or the oxygen concentration reaches 30,000 [ppm], or the nitrogen concentration reaches any one of 60,000 [ppm]. The method of managing and maintaining the on-load tap changer according to claim 1, wherein the on-load tap changer comprises:   The method according to claim 1, wherein the timing is when the number of times of operation of the vacuum valve switch has reached 100,000 times and a multiple thereof.   The method according to claim 1, wherein the timing is 10 years after the start of operation of the vacuum valve type switching switch and a time point when it has reached its multiple years.   The method according to any one of claims 1 to 4, wherein the insulating oil is a vegetable oil.

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