JP2015046458A - Minor oil leakage detection device of transformer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a minor oil leakage detection device of a transformer capable of detecting minor oil leakage without depending on changes in oil level.SOLUTION: The device comprises: an airflow sensor 21 for detecting the flow rate of the air flowing into and out of a conservator 10 via an air passage 14; an air temperature sensor 22 for detecting the temperature of the air passing through the air passage 14; an insulating oil temperature sensor 24 for detecting the temperature of insulating oil F; oil amount increasing/decreasing conversion means 25 for calculating an increase/decrease in volume of the insulating oil F due to a temperature change based on the signal from the airflow sensor 21 and the signal from the air temperature sensor 22; and insulating oil leakage determination means 26 for accumulating correlation data G between the oil temperature and the increase/decrease of the oil amount based on the signal from the insulating oil temperature sensor 24 and the value obtained by calculating the increase/decrease of the volume of the insulating oil F by the oil amount increasing/decreasing conversion means 25, and thereby determining the leakage of the insulating oil F to the outside based on the control value of the correlation data G.

Description

  The present invention relates to a micro oil leakage detection device for a transformer capable of detecting micro oil leakage from a transformer having a conservator.

  Insulation oil is sealed in large transformers installed at power stations, and it is regularly checked for leaks of insulation oil. The presence or absence of leakage of the insulating oil is determined, for example, by checking the oil level gauge of the conservator that communicates with the transformer and the temperature of the insulating oil at the time of patrol, and by changes due to trend management. The leakage of insulating oil from a large transformer has a great effect if it leaks even if it is a small amount, so it is required to detect the oil leak as soon as possible.

  Conventionally, as a prior art related to oil leakage, an abnormality monitoring device for an oil feeder and an oil leakage detection device for a hydraulic elevator are known (for example, see Patent Literatures 1 and 2). The equipment samples the oil level signal from the oil level detector of the conservator and the oil temperature signal from the oil temperature detector of the insulating oil of the transformer at regular intervals, and the oil level change rate or oil amount with respect to oil temperature change. The rate of change is calculated. The oil leakage detection device for a hydraulic elevator disclosed in Patent Document 2 floats a float in a tank containing hydraulic oil, and detects oil leakage based on a signal from a differential transformer interlocked with the float.

JP-A-5-182838 JP 2007-302365 A

  However, the temperature of the insulating oil in the transformer is remarkably changed, and the oil level changes greatly even if the oil leaks due to expansion and contraction. In order to absorb expansion and contraction of insulating oil due to temperature changes, the transformer has a conservator at the top that communicates with the interior of the transformer. Exists.

  FIG. 6 shows the relationship between the shape of the conservator 10 and the oil level of the insulating oil F. When the conservator 10 having a cylindrical shape is managed by the oil level, for example, the maximum oil level and the intermediate oil level In some cases, the change in the oil level with respect to the increase or decrease in the oil amount is significantly different. That is, in the horizontal cylindrical conservator 10 of FIG. 6, as shown in FIG. 6A, the change in the oil level F1 when the oil amount is changed from 50% to 49%, and FIG. As shown in Fig. 6, the change in the oil level F2 when the oil amount is changed from 95% to 94%, the change in the oil level is larger in Fig. 6 (b), and the oil leakage based on the change in the oil level There is a problem with detection. Since the technologies related to Patent Documents 1 and 2 described above are detection based on the oil level as in FIG. 6, it is difficult to detect with high accuracy, and there is a limit to detection of minute oil leakage.

  Accordingly, an object of the present invention is to provide a transformer minute oil leakage detection device capable of detecting minute oil leakage without being based on a change in oil level.

  In order to achieve the above object, the invention according to claim 1 is provided in an air passage for introducing the atmosphere into a conservator attached to an upper portion of the transformer, and is adapted to the temperature change of the insulating oil in the transformer. An air flow sensor for detecting a flow rate of air flowing into and out of the conservator via the air passage according to a change in volume of the insulating oil, and an air temperature sensor for detecting a temperature of the air flowing through the air passage; An oil amount increase / decrease for calculating an increase / decrease in the volume of the insulating oil due to a temperature change based on an insulating oil temperature sensor for detecting the temperature of the insulating oil, a signal from the air flow sensor and a signal from the air temperature sensor Correlation data between the oil temperature of the insulating oil and the oil amount increase / decrease based on the conversion means, the signal from the insulating oil temperature sensor and the calculated increase / decrease in volume of the insulating oil by the oil amount increase / decrease conversion means In addition, the present invention provides a micro oil leakage detection device for a transformer, comprising: insulation oil leakage determination means for determining whether there is an abnormality in leakage of the insulation oil to the outside based on a management value of the correlation data. .

  According to this invention, based on the signal from the air flow sensor and the signal from the air temperature sensor, the increase / decrease in the volume of the insulating oil due to the temperature change is calculated by the oil amount increase / decrease conversion means. Correlation data between the oil temperature of the insulating oil and the increase / decrease in the oil amount is accumulated based on the signal from the insulating oil temperature sensor and the calculated value of the increase / decrease in the volume of the insulating oil by the oil amount increase / decrease conversion means. Based on the value, the insulating oil leakage determining means determines whether there is an abnormality in leakage of the insulating oil to the outside.

  According to a second aspect of the present invention, there is provided the micro oil leakage detection device for a transformer according to the first aspect, wherein the insulating oil leakage determination means provides a centralized control station in a remote location with an abnormal alarm of the insulating oil leakage. It is characterized in that alarm output means for outputting is connected.

  According to the first aspect of the present invention, the change in the volume of the insulating oil of the transformer with respect to the temperature change is replaced with the volume of air entering and exiting the conservator using the air flow sensor and the air temperature sensor. Regardless of the shape, the increase / decrease in the volume of the insulating oil with respect to the temperature change can be calculated with high accuracy, and a minute oil leak from the transformer can be detected quickly. Therefore, it is possible to prevent the insulating oil leaking from the transformer from flowing into the irrigation channel.

  According to the second aspect of the present invention, the insulating oil leakage determining means is connected to the alarm output means for outputting an abnormality alarm of the insulating oil leakage to the centralized control station at a remote location. Even when it is installed in a remote place, it is possible to quickly cope with leakage of insulating oil from the transformer.

It is a block diagram which shows the outline | summary of the micro oil leakage detection apparatus of the transformer concerning embodiment of this invention. It is an expanded sectional view of the conservator regarding the micro oil leakage detection apparatus of the transformer of FIG. It is sectional drawing at the time of seeing the conservator of FIG. 2 from the horizontal direction. It is a whole block diagram of the micro oil leakage detection apparatus of the transformer of FIG. It is a flowchart which shows the flow of the detection processing procedure in the micro oil leakage detection apparatus of the transformer of FIG. It is a perspective view which shows the difference of the change of the oil level in the conservator of a transformer.

  Next, embodiments of the present invention will be described in detail with reference to the drawings.

  1 to 5 show an embodiment of the present invention, and particularly show a case where the present invention is applied to a large transformer 1 arranged in a facility of a power supply company. As shown in FIG. 2, a conservator 10 is provided on the upper portion of the transformer 1. The conservator 10 includes a tank body 11, a connecting pipe 12, an oil discharge valve 13, a breather pipe 14 as an air passage, a rubber film 15, an oil level gauge 16, an air vent valve 17, a vacuum valve 18, And a shutoff prevention valve 19.

  The connecting pipe 12 has a function of communicating the transformer 1 and the conservator 10. When the insulating oil F in the transformer 1 expands or contracts due to a temperature change, the insulating oil F in the conservator 10 is provided. The amount of oil increases and decreases. There is a negative pressure between the upper part of the conservator 10 and the rubber film 15, and the rubber film 15 is swollen by the negative pressure. The rubber film 15 communicates with the atmosphere via the breather pipe 14, and air A 1 from the atmosphere flows into the rubber film 15. The oil level gauge 16 is interlocked with a float 16 a provided in the conservator 10 so that the position of the oil level of the insulating oil F can be grasped by the dial type oil level gauge 16 from the outside.

  In the vicinity of the transformer 1, a transformer minute oil leakage detection device 20 is provided. As shown in FIG. 1, the transformer minute oil leakage detection device 20 includes an air flow rate sensor 21, an air temperature sensor 22, an insulating oil temperature sensor 24, an oil amount increase / decrease conversion means 25, and an insulating oil leak determination means. 26 and an alarm output means 27.

  As shown in FIG. 4, an air flow sensor 21 and an air temperature sensor 22 are provided in the middle of the breather pipe 14 as an air passage. A breather 23 is attached to the end of the breather tube 14. The breather 23 functions as a respiratory organ, and has a function of introducing the atmosphere into the conservator 10 and releasing the air A1 in the conservator 10 to the atmosphere side. The breather 23 also has a dehumidifying function for removing moisture contained in the passing air A2. In this embodiment, an air flow sensor 21 is disposed between the air temperature sensor 22 and the breather 23.

  The air flow rate sensor 21 measures the flow rate of the air A2 that enters and exits the conservator 10 via the breather pipe 14 serving as an air passage according to the volume change of the insulation oil F accompanying the temperature change of the insulation oil F in the transformer 1. It has a function to detect. The air temperature sensor 22 has a function of detecting the temperature of the air A2 flowing through the breather pipe 14 serving as an air passage. The signal from the air flow sensor 21 and the signal from the air temperature sensor 22 are input to the oil amount increase / decrease conversion means 25. The oil amount increase / decrease conversion means 25 includes a passing air amount (density) detection circuit 25a and an oil amount increase / decrease conversion circuit 25b. The oil amount increase / decrease conversion means 25 has a function of calculating an increase / decrease in the volume of the insulating oil F due to a temperature change based on a signal from the air flow sensor 21 and a signal from the air temperature sensor 22.

  On the transformer 1 side, an insulating oil temperature sensor 24 that detects the temperature of the insulating oil F in the transformer 1 is provided. The output signal from the oil amount increase / decrease conversion means 25 and the output signal from the insulating oil temperature sensor 24 are input to the insulating oil leakage determination means 26. The insulating oil leakage determination means 26 includes an oil temperature detection circuit 26a, an oil temperature-oil amount increase / decrease correlation data storage circuit 26b, a variation allowable value determination circuit 26c at the time of a new product and after repair, and an oil amount decrease tendency detection circuit 26d. , An oil amount reduction continuity evaluation circuit 26e and a management value deviation detection circuit 26f are provided. The insulating oil leakage determination means 26 correlates the oil temperature of the insulating oil F with the oil amount increase / decrease based on the signal from the insulating oil temperature sensor 24 and the calculated value of the increase / decrease in the volume of the insulating oil F by the oil amount increase / decrease conversion means 25. Data G is accumulated, and based on the management value of the correlation data G, it has a function of determining whether there is an abnormality in leakage of the insulating oil F to the outside. The management value deviation detection circuit 26f of the insulating oil leakage determination means 26 is connected to an alarm output means 27 for outputting an abnormality alarm for leakage of the insulating oil F to a centralized control station at a remote location.

  Correlation data G includes the relationship between the oil temperature of the insulating oil F and the amount of oil for a period of, for example, several months from the completion of installation or refurbishment of the transformer 1 from the viewpoint of improving the detection accuracy of oil leakage. Periodically measured values are stored as a database. As shown in FIG. 4, in the correlation data G, an average line and an alarm determination line are set, and the alarm determination line is used as a management value for oil leakage.

  Next, the detection processing procedure and operation in the transformer minute oil leakage detection device 20 will be described.

  FIG. 5 shows a flow of a detection processing procedure in the minute oil leakage detection apparatus 20. As shown in FIG. 5, in step 41, the air flow rate sensor 21 detects the flow rate of the air A <b> 2 that enters and exits the conservator 10 through the breather pipe 14 serving as an air passage. Next, the routine proceeds to step 42 where the temperature of the air A2 entering and exiting the conservator 10 via the breather pipe 14 as an air passage is detected by the air temperature sensor 22. Next, the process proceeds to step 43, and based on the signal from the air flow rate sensor 21 and the signal from the air temperature sensor 22, the increase / decrease in the volume of the insulating oil F due to the temperature change is calculated by the oil amount increase / decrease conversion means 25. In step 44, the temperature of the insulating oil F in the transformer 1 is detected by the insulating oil temperature sensor 24. In step 45, the relationship between the oil temperature of the insulating oil F and the oil amount is periodically determined based on the signal from the insulating oil temperature sensor 24 and the calculated value of the increase / decrease in the volume of the insulating oil F by the oil amount increase / decrease conversion means 25. The measured values are stored as a database.

  In step 46, it is determined whether or not the oil amount tends to decrease by the oil amount decrease tendency detection circuit 26d. Here, when the amount of oil does not tend to decrease, the process returns to step 41 and the above-described processing is repeated. If it is determined in step 46 that the oil amount tends to decrease, the process proceeds to step 47. In step 47, it is determined by the oil quantity reduction continuity evaluation circuit 26e whether or not the oil quantity reduction has continuity. If it is determined in step 47 that the oil amount does not have a continuity, the process returns to step 41 and the above-described processing is repeated. If it is determined in step 47 that the oil amount decreasing tendency is continuous, the process proceeds to step 48. In step 48, it is determined by the management value deviation detection circuit 26f whether or not the oil leakage management value has deviated from the oil leakage reduction value. If it is determined in step 48 that the oil amount decrease does not deviate from the oil leakage management value, the process returns to step 41 and the above-described processing is repeated. If it is determined in step 48 that the oil amount decrease has deviated from the oil leakage management value, the routine proceeds to step 49, where the alarm output means 27 outputs an abnormality alarm for leakage of the insulating oil F, and this abnormality alarm is Sent to a centralized control station at a remote location.

  Thus, in the present invention, the change in the volume of the insulating oil F of the transformer 1 with respect to the temperature change is replaced with the volume of air entering and exiting the conservator 10 using the air flow rate sensor 21 and the air temperature sensor 22. Regardless of the shape of the conservator 10, the increase / decrease of the volume of the insulating oil F with respect to the temperature change can be calculated with high accuracy, and a minute oil leak from the transformer 1 can be detected quickly. Therefore, it is possible to prevent the insulating oil F leaking from the transformer 1 from flowing into the irrigation channel. That is, as shown in FIG. 6, in the horizontal cylindrical conservator 10 shown in FIG. 6, as described above, even when the insulating oil F increases or decreases by the same volume depending on the temperature, FIG. 6 (b), the change in the oil level is larger in the change in the oil level F1 in FIG. 6 (a) and the change in the oil level F2 in FIG. 6 (b), and the oil leak is detected based on the change in the oil level. However, as in the present invention, the change in the volume of the insulating oil F of the transformer 1 with respect to the temperature change is replaced with the volume of the air entering and exiting the conservator 10, regardless of the shape of the conservator 10. Therefore, the change in the volume of the insulating oil F of the transformer 1 can be grasped with high accuracy, and a minute oil leak from the transformer 1 can be detected quickly.

  The insulating oil leakage determination means 26 is connected to an alarm output means 27 for outputting an abnormality alarm of leakage of the insulating oil F to a centralized control station located at a remote location, so that the transformer 1 is installed at a remote location. Even if it is, it becomes possible to cope with the leakage of the insulating oil F at an early stage.

  The embodiment of the present invention has been described in detail above, but the specific configuration is not limited to the above-described embodiment, and even if there is a design change or the like without departing from the gist of the present invention, It is included in this invention. For example, in this embodiment, the temperature of the insulating oil F is detected only by the insulating oil temperature sensor 24 provided on the transformer 1 side, but measured at a plurality of locations such as the conservator 10 and the connecting pipe 12. The average value may be used as the temperature of the insulating oil F.

1 transformer 10 conservator 12 connecting pipe 14 breather pipe (air passage)
21 Air flow sensor 22 Air temperature sensor 24 Insulating oil temperature sensor 25 Oil amount increase / decrease conversion means 25a Passed air amount detection circuit 25b Oil amount increase / decrease conversion circuit 26 Insulated oil leak determination means 26a Oil temperature detection circuit 26b Oil temperature-oil amount increase / decrease correlation Property data storage circuit 26c variation allowance value determination circuit 26d when new and after repair 26d oil amount decrease tendency detection circuit 26e oil amount decrease continuity evaluation circuit 26f management value deviation detection circuit 27 alarm output means F insulating oil

Claims (2)

Provided in an air passage for guiding the atmosphere into a conservator attached to the upper part of the transformer, and through the air passage according to the volume change of the insulating oil accompanying the temperature change of the insulating oil in the transformer An air flow sensor for detecting the flow rate of air entering and exiting the conservator;
An air temperature sensor for detecting the temperature of the air flowing through the air passage;
An insulating oil temperature sensor for detecting the temperature of the insulating oil;
Based on a signal from the air flow sensor and a signal from the air temperature sensor, an oil amount increase / decrease conversion means for calculating an increase / decrease in the volume of the insulating oil due to a temperature change;
Based on a signal from the insulating oil temperature sensor and a calculated value of increase / decrease in volume of the insulating oil by the oil amount increase / decrease conversion means, correlation data between oil temperature of the insulating oil and increase / decrease in oil amount is accumulated, Insulating oil leakage determination means for determining whether there is an abnormality in leakage of the insulating oil to the outside based on a management value of data;
A micro-leakage detection device for a transformer characterized by comprising:   2. The transformer according to claim 1, wherein the insulating oil leakage determination unit is connected to an alarm output unit that outputs an abnormality alarm of the insulating oil leakage to a centralized control station at a remote location. Micro oil leakage detection device.

Images