JP5022746B2 - Insulation abnormality diagnosis method and insulation abnormality diagnosis apparatus for electrical equipment - Google Patents

Description

  The present invention relates to an insulation abnormality diagnosis method and an insulation abnormality diagnosis apparatus for an electrical facility that determines the presence or absence of an insulation abnormality location by detecting ultraviolet rays radiated along with creeping discharge generated on the surface of the electrical facility in operation. .

  In electrical equipment such as transformers, fouling substances such as salt and dust adhere to the insulation over time or the environment, and if such fouling material absorbs moisture, the electrical resistance of the insulation surface decreases, causing failure or accidents. May cause. It is known that when the electrical resistance of the insulator surface decreases, creeping discharge occurs on the equipment surface, and discharge current flows and electromagnetic waves, ultrasonic waves, ultraviolet rays, etc. are radiated simultaneously. For this reason, conventionally, the presence or absence of abnormal insulation has been diagnosed by detecting these physical quantities. However, since the physical quantity generated along with the discharge is very weak, it has become a problem how to accurately extract only the physical quantity associated with the discharge from the measurement signal including noise.

  FIG. 17A shows an example of a waveform of a current flowing through the ground line when a discharge occurs, and FIG. 17B shows an example of an AC voltage waveform applied to the electrical equipment at that time. Discharge occurs when the voltage applied to the location where the discharge occurs exceeds a certain threshold value, and stops when the voltage falls below the threshold value. For this reason, it often has a specific pattern that occurs twice during one cycle of the applied AC voltage. In addition, once discharge starts, it often continues for a certain period of time. The presence or absence of discharge is determined based on the characteristics of such a discharge phenomenon.

  As prior art, Patent Documents 1 and 2 disclose a method for detecting and judging ultrasonic waves accompanying discharge. This method extracts the frequency component peculiar to the discharge from the signal captured by the ultrasonic sensor and detects the envelope, and then extracts the frequency component twice the applied AC voltage from the signal, The presence / absence of discharge is judged by strength.

In Patent Document 3, the current waveform flowing in the ground line due to the occurrence of partial discharge is measured over several tens of cycles, and frequency components that are significantly different from the background noise are extracted from the current waveform. An apparatus to be presented is disclosed.
JP 2001-305178 A Japanese Patent Laid-Open No. 09-127181 JP 2004-101418 A

  However, in the conventional method for detecting ultrasonic waves and grounding line current, when the creeping discharge intensity is weak, the signal level of the discharge sound and discharge current contained in the ultrasonic wave and grounding line current is low. It is difficult to separate a signal and noise, and it is difficult to determine whether or not a discharge has occurred.

  SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and the purpose of the present invention is to diagnose the insulation abnormality of electrical equipment that can detect the presence or absence of insulation abnormality by reliably detecting the presence or absence of creeping discharge even with a weak discharge. A method and an insulation abnormality diagnosis apparatus are provided.

In order to achieve the above object, an insulation abnormality diagnosis method for electrical equipment according to claim 1 and an insulation abnormality diagnosis device for electrical equipment according to claim 6 are accompanied by creeping discharge generated on the surface of the electrical equipment in operation. An insulation abnormality diagnosis method and an insulation abnormality diagnosis apparatus for an electrical facility that determines the presence or absence of an insulation abnormality by detecting emitted ultraviolet light, measuring the accumulated number of times of ultraviolet light detection, and measuring the accumulated number of times of detection within a predetermined time. It is characterized in that it is determined that there is an abnormality in insulation when the inclination exceeds a predetermined threshold value.

The slope of the cumulative number of UV detections when discharge is not occurring (that is, UV light due to ambient light) is almost constant over time, whereas the slope of the cumulative number of UV detections when discharge is occurring Will change. According to the first and sixth aspects of the present invention, it can be determined that the discharge has occurred when the slope of the cumulative number of UV detections within a predetermined time changes and exceeds a predetermined threshold value.

Ultraviolet rays emitted during discharge can be detected even when the discharge intensity is weak, but at the same time, ultraviolet rays caused by causes other than discharge such as disturbance light are also detected. On the other hand, according to the configuration of claims 1 and 6 , since the presence or absence of an insulation abnormality point is determined based on whether or not the slope of the cumulative number of UV detection times within a predetermined time satisfies a predetermined condition, It is possible to determine the presence or absence of an abnormal insulation location more accurately.

The insulation abnormality diagnosis method for electrical equipment according to claim 2 and the insulation abnormality diagnosis apparatus for electrical equipment according to claim 7 measure a time interval at which ultraviolet rays are detected, and specify an ultraviolet detection time interval measured within a predetermined time. It is characterized in that it is judged that there is an insulation abnormality part when it is concentrated in the interval range.

The UV detection time interval when there is no discharge (that is, the UV detection time interval due to ambient light) varies widely and the data is distributed over a wide range, whereas the UV detection time interval when discharge is occurring Variation is small and data is concentrated and distributed at a specific time interval. According to the configurations of claims 2 and 7 , it can be determined that a discharge has occurred when the UV detection time intervals measured within a predetermined time are concentrated and distributed in a specific interval range.

Insulation abnormality diagnosis apparatus for electrical equipment according to claim 3 of the electrical equipment according insulating abnormality diagnosis method and claim 8 measures the applied voltage phase of the electrical equipment at the time of detection of the UV was measured within a predetermined time It is characterized in that it is determined that there is an insulation abnormality location when the voltage phase at the time of UV detection is concentrated and distributed in a specific phase range.

The applied voltage phase at the time of detecting the ultraviolet ray when no discharge has occurred (that is, the applied voltage phase when detecting the ultraviolet ray due to disturbance light) is evenly distributed from 0 to 360 degrees, whereas the discharge is generated. The applied voltage phase at the time of detecting the ultraviolet rays in the case where the light is present concentrates on a specific phase. According to the configurations of claims 3 and 8 , it can be determined that discharge has occurred when the voltage phase during UV detection measured within a predetermined time is concentrated and distributed in a specific phase range.

The insulation abnormality diagnosis method for electrical equipment according to claim 4 and the insulation abnormality diagnosis apparatus for electrical equipment according to claim 9 measure an applied voltage phase of the electrical equipment at the time when ultraviolet rays are detected and are measured within a predetermined time. It is characterized in that it is determined that there is an insulation abnormality part when the number of voltage phases at the time of detecting a specific ultraviolet ray exceeds a predetermined threshold value.

The number of times the voltage phase during UV detection when the discharge is occurring is a specific phase is the voltage phase when UV is detected when there is no discharge (that is, the voltage phase when UV light is detected due to ambient light) More than the number of phases. According to the configurations of claims 4 and 9 , it can be determined that a discharge has occurred when the number of times of a specific UV detection voltage phase measured within a predetermined time exceeds a predetermined threshold.

An insulation abnormality diagnosis method for electrical equipment according to claim 5 and an insulation abnormality diagnosis device for electrical equipment according to claim 10 include the number of times of detection of ultraviolet rays, the time interval at which ultraviolet rays are detected, and the electrical equipment at the time of detection of ultraviolet rays. The applied voltage phase is measured, and the number of UV detection times within a predetermined time, the UV detection time interval measured within the predetermined time, and the number of voltage phases during specific UV detection measured within the predetermined time are used as variables. It is characterized in that the presence / absence of an insulation abnormality point is determined by comparing the calculated Mahalanobis distance with a predetermined threshold value.

The Mahalanobis distance when the discharge is generated is distributed to a relatively small value, whereas the Mahalanobis distance when the discharge is not generated is distributed to a larger value. According to the structure of Claim 5 and 10 , the presence or absence of discharge can be determined by comparing the Mahalanobis distance with a predetermined threshold value.

  Even if it is difficult to determine only the number of UV detection times within a predetermined time, only the UV detection time interval within a predetermined time, or only the number of voltage phases during UV detection within a predetermined time, it is based on the Mahalanobis distance. Thus, the presence / absence of the occurrence of discharge can be determined, the accuracy of determining the presence / absence of an insulation abnormality location is increased, and the reliability of the diagnosis result is improved.

  According to the present invention, it is possible to determine whether or not a discharge has occurred based on whether or not various kinds of information obtained from the detected ultraviolet rays within a predetermined time satisfy a predetermined condition, and even creeping discharge can be reliably performed. The presence or absence of insulation abnormality can be determined by detecting the presence or absence of occurrence.

(First embodiment)
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. 1 to 3. FIG. 1 is a block diagram showing the configuration of an insulation abnormality diagnosis apparatus. The insulation abnormality diagnosis device 1 judges (diagnosis) the presence or absence of an insulation abnormality part by detecting ultraviolet rays radiated along with the creeping discharge generated on the surface of the electrical equipment (transformer) in operation. It comprises an ultraviolet sensor 2 (corresponding to ultraviolet detection means) and a signal processing device 3 (corresponding to judgment means, measurement means, detection frequency measurement means, time interval measurement means, voltage phase measurement means, Mahalanobis distance calculation means). Yes. The ultraviolet sensor 2 is installed in the vicinity of an electrical facility that is an object of insulation abnormality diagnosis, for example, the transformer 4, and detects ultraviolet rays generated by discharge at an insulation abnormality portion on the surface of the transformer 4. The ultraviolet sensor 2 outputs a pulsed voltage signal when detecting ultraviolet rays.

  The signal processing device 3 includes a signal processing circuit 5 and an information processing device 6 such as a personal computer. The signal processing circuit 5 includes a detection frequency data memory 7, a voltage phase data memory 8, a CPU (not shown), and the like. The signal processing circuit 5 includes the voltage signal output from the ultraviolet sensor 2 and the voltage transformation. The phase signal (applied voltage phase signal) of the voltage applied to the device 4 is input. The signal processing circuit 5 stores the number (number of pulses) of the voltage signal output from the ultraviolet sensor 2 in the detection number data memory 7 as the ultraviolet detection number data Ci, and applies the transformer 4 at the time when the ultraviolet ray is detected. The voltage phase signal is stored in the voltage phase data memory 8 as the voltage phase data Pi when UV is detected.

  The information processing device 6 includes a CPU, a RAM, a ROM, an input / output interface, a bus connecting them, a power supply device, a hard disk device, and the like (not shown). This information processing device 6 receives the UV detection frequency data Ci stored in the detection frequency data memory 7 and the UV detection voltage phase data Pi stored in the voltage phase data memory 8 for a certain period of time (waiting described later). They are taken in every time T1). Then, the information processing device 6 diagnoses the presence or absence of an insulation abnormality portion of the transformer 4 in accordance with the diagnostic program, using the acquired ultraviolet detection number data Ci and ultraviolet detection voltage phase data Pi.

Next, an insulation abnormality diagnosis method executed by the information processing apparatus 6 in the insulation abnormality diagnosis apparatus 1 will be described.
FIG. 2 is a flowchart showing an insulation abnormality diagnosis procedure in the present embodiment. First, in step S <b> 1, ultraviolet detection frequency data Ci is acquired from the signal processing circuit 5. Next, in step S2, the ultraviolet detection frequency data Ci acquired in step S1 is added to the cumulative detection frequency data Cs to obtain new cumulative detection frequency data Cs. While the inclination calculation target time T2 does not elapse as the predetermined time (step S3: NO), the information processing apparatus 6 proceeds to step S7 and waits until the standby time T1 elapses (S7: NO). When T1 has elapsed (S7: YES), the process returns to step S1.

  In step S3 described above, when the inclination calculation target time T2 has elapsed (YES), the information processing apparatus 6 proceeds to step S4, and based on the cumulative detection count data Cs, the cumulative detection count within the tilt calculation target time T2 is set. A slope D (increase in the cumulative number of detections) is calculated. In step S5, the slope D of the cumulative number of detections calculated in step S4 is compared with a predetermined threshold value Dth. When the slope D exceeds the threshold value Dth (S5: YES), the information processing apparatus 6 determines that there is an insulation abnormality part, and proceeds to the insulation abnormality process in step S6. In step S6, for example, a predetermined process is performed when an insulation abnormality occurs, such as generating an alarm or describing a diagnosis result in a file. If the slope D is equal to or less than the threshold value Dth (S5: NO), the process waits until the standby time T1 elapses in step S7, and then returns to step S1.

  FIG. 3A shows an example of the cumulative number of times of detection of ultraviolet rays (that is, ultraviolet rays due to disturbance light) when no creeping discharge occurs in the transformer 4 (when no discharge occurs), and FIG. An example of the cumulative number of UV detection times when a creeping discharge has occurred (during discharge) is shown. In this case, the standby time T1 in step S7 is 10 seconds, the slope calculation target time T2 in step S3 is 60 minutes, and the total ultraviolet measurement time is 120 minutes.

  In FIG. 3A, the slope D of the cumulative detection count for 60 minutes from the start of measurement is 8 times / hour, and the slope D of the cumulative detection count for 60 minutes from 60 minutes to 120 minutes is 13 times / hour. On the other hand, in FIG. 3B, the slope D of the cumulative detection frequency for 60 minutes from the start of measurement is 13 times / hour, and the slope D of the cumulative detection frequency for 60 minutes from 60 minutes to 120 minutes changes at 63 times / hour. To do. Thus, while the slope D of the cumulative number of UV detections due to ambient light is substantially constant, the slope D changes when creeping discharge occurs. Therefore, the presence or absence of discharge can be determined by setting the threshold value Dth to 20 times / hour, for example.

  As described above, in the present embodiment, the cumulative number of detection times of ultraviolet rays is measured, and discharge occurs when the slope D of the cumulative number of detections within a predetermined time (inclination calculation target time T2) exceeds a predetermined threshold value Dth. Therefore, it is possible to reliably detect the presence or absence of creeping discharge and determine the presence or absence of an insulation abnormality with high reliability even with a weak discharge having the same intensity as ambient light.

(Second Embodiment)
Next, a second embodiment of the present invention will be described with reference to FIGS. In the present embodiment and third to sixth embodiments described later, the configuration of the insulation abnormality diagnosis device is the same as that shown in FIG.

  FIG. 4 is a flowchart showing an insulation abnormality diagnosis procedure in the present embodiment. First, in step S <b> 21, ultraviolet detection frequency data Ci is acquired from the signal processing circuit 5. Next, in step S22, the ultraviolet detection number data Ci acquired in step S21 is stored in the array CNT holding the number of ultraviolet detections. The information processing device 6 proceeds to step S27 and waits until the standby time T1 elapses (S27: NO) while the calculation target time T3 of the detection count sum does not elapse as the predetermined time (step S23: NO). When the standby time T1 has elapsed (S27: YES), the process returns to step S21.

  In step S23 described above, when the detection time sum calculation target time T3 has elapsed (YES), the information processing apparatus 6 proceeds to step S24, and calculates the sum of the elements of the array CNT as the ultraviolet detection number CS. In step S25, the number of UV detection times CS calculated in step S24 is compared with a predetermined threshold value CSth. When the number of UV detection times CS exceeds the threshold value Cth (S25: YES), it is determined that there is an insulation abnormality part, and the process proceeds to an insulation abnormality process in step S26. If the number of UV detection times CS is equal to or less than the threshold value Cth (S25: NO), after waiting in step S27 until the waiting time T1 has elapsed, the process returns to step S21.

  FIG. 5 shows an example of the frequency distribution of the number of UV detections CS for 10 minutes when no creeping discharge occurs in the transformer 4 (when not discharging) and when creeping discharge occurs (when discharging). In this case, the waiting time T1 in step S27 was 10 seconds, the calculation target time T3 of the sum of detection times in step S23 was 10 minutes, and the total ultraviolet measurement time was 120 minutes. The number of UV detection times CS when not discharged is distributed from 0 to 9 times and does not exceed 10 times. On the other hand, the number of UV detection times CS at the time of discharge is distributed from 0 to 46 times, and is frequently 10 times or more. This is because the number of times of detection of ultraviolet rays by discharge light is added to the number of times of detection of ultraviolet rays by disturbance light when a discharge occurs. As described above, the number of times of UV detection during the calculation target time T3 of the sum of detection times is larger during discharge than during non-discharge. Therefore, the presence or absence of discharge can be determined by setting the threshold value CSth to ten.

  As described above, in this embodiment, it is determined that the discharge has occurred when the number of UV detection times CS within a predetermined time (the calculation target time T3 of the detection frequency sum) exceeds a predetermined threshold value CSth. Even with a weak discharge having the same strength, it is possible to reliably detect the presence or absence of creeping discharge and determine the presence or absence of an insulation abnormality with high reliability.

It is technically difficult to accurately measure the number of creeping discharges depending on the degree of soiling and moisture on the surface of an insulator in an operating electrical facility with a poor noise environment.
In the present embodiment, the presence / absence of an abnormal insulation point is determined based on the number of UV detection times CS correlated with the number of discharges, not the number of discharges. In other words, since the presence or absence of an insulation abnormality location is determined based on whether or not the number of UV detections within a predetermined time satisfies a predetermined condition, even if the actual number of discharges cannot be measured, the presence or absence of an insulation abnormality location is more accurately detected. Can be judged.

(Third embodiment)
Next, a third embodiment of the present invention will be described with reference to FIGS.
FIG. 6 is a flowchart showing an insulation abnormality diagnosis procedure in the present embodiment. First, in step S31, ultraviolet detection frequency data Ci is acquired from the signal processing circuit 5. Next, in step S32, the ultraviolet detection number data Ci acquired in step S31 is stored in the array CNT holding the number of ultraviolet detections. While the predetermined time T4 has not elapsed since the previous calculation of the kurtosis K (see step S35) (step S33: NO), the information processing apparatus 6 proceeds to step S38 and waits until the standby time T1 has elapsed. (S38: NO) When the standby time T1 has elapsed (S38: YES), the process returns to step S31.

  In step S33 described above, when the predetermined time T4 has elapsed (YES), the information processing apparatus 6 proceeds to step S34, calculates the ultraviolet detection time interval using the elements of the array CNT, and holds this ultraviolet detection time interval. An array INT is generated.

Here, a method of generating the array INT will be described with reference to FIG. When data is stored in the array CNT as shown in FIG. 7, ultraviolet rays are detected at least once by CNT [j + 0], CNT [j + 3], and CNT [j + 8]. Therefore, when calculating the difference between the indexes of adjacent arrays (in this case, CNT [j + 0] and CNT [j + 3], CNT [j + 3] and CNT [j + 8]) among the arrays CNT that detect these ultraviolet rays,
(J + 3)-(j + 0) = 3
(J + 8)-(j + 3) = 5
It becomes. Since the index of the array CNT increases by 1 for each waiting time T1, if the index difference is 3, 3T1 is stored in INT [0], and if the index difference is 5, 5T1 is stored in INT [1]. . This procedure is repeated from index [j + 0] to [j + T4 / T1].

In step S35, the kurtosis K is calculated using the elements of the generated array INT. In this case, the kurtosis K is expressed by the following equation (1), where m is the average of the array INT (INT [0], INT [1],..., INT [n−1]), and σ is the standard deviation. calculate.

  The kurtosis degree K is a scale indicating the degree of concentration of data around the average, and the value increases as the data concentrates. In step S36, the calculated kurtosis K is compared with a predetermined threshold value Kth. When the kurtosis K exceeds the threshold value Kth (S36: YES), the information processing apparatus 6 determines that there is an insulation abnormality part, and proceeds to insulation abnormality processing in step S37. If the kurtosis K is equal to or less than the threshold value Kth (S36: NO), after waiting in step S38 until the waiting time T1 elapses, the process returns to step S31.

  FIG. 8 shows an example of the frequency distribution of the UV detection time interval when no creeping discharge occurs in the transformer 4 (when not discharging) and when creeping discharge occurs (when discharging). In this case, the waiting time T1 in step S38 is 10 seconds, and the predetermined time T4 in step S33 is 120 minutes. When the discharge occurs, the ultraviolet detection time interval is shortened, and therefore, the ultraviolet detection time interval data at the time of discharge is concentrated in a shorter time interval range (a range on the left end side in FIG. 8) than at the time of non-discharge. Further, when the kurtosis K of the detection time interval data is calculated based on the data shown in FIG. 8, the kurtosis K at the time of discharge is 14.2 and the kurtosis K at the time of non-discharge is 5.3. Therefore, by setting the threshold value Kth to 10, the presence or absence of discharge can be determined.

  As described above, in the present embodiment, the time intervals (array INT) at which ultraviolet rays are detected are measured, and it is determined that a discharge has occurred when the ultraviolet ray detection time intervals within the predetermined time T4 are concentrated in a specific interval range. Therefore, even with a weak discharge having the same intensity as that of disturbance light, it is possible to reliably detect the presence or absence of creeping discharge and determine the presence or absence of an insulation abnormality with high reliability.

As described in the second embodiment, it is difficult to measure the exact number of discharges. In the present embodiment, the presence / absence of an abnormal insulation portion is determined based on the UV detection time interval correlated with the number of discharges, not the number of discharges. In other words, since the presence or absence of abnormal insulation is determined based on whether or not the UV detection time interval measured within a predetermined time satisfies a predetermined condition, insulation can be performed more accurately even if the actual number of discharges cannot be measured. The presence or absence of abnormal parts can be determined.
In the present embodiment, an example in which the kurtosis K is used as an index for concentrating data is shown, but an index indicating the degree of data variation such as variance may be used.

(Fourth embodiment)
Next, a fourth embodiment of the present invention will be described with reference to FIGS.
FIG. 9 is a flowchart showing a procedure for diagnosing insulation abnormality in the present embodiment. First, in step S41, the voltage phase data Pi at the time of ultraviolet detection is acquired from the signal processing circuit 5. Next, in step S42, the ultraviolet detection voltage phase data Pi acquired in step S41 is stored in the array PHS that holds the detection phase. As long as the predetermined time T5 has not elapsed since the previous calculation of the degree of distortion S (see step S44) (step S43: NO), the information processing apparatus 6 proceeds to step S47 and waits until the standby time T1 has elapsed. (S47: NO) When the standby time T1 has elapsed (S47: YES), the process returns to step S41.

In step S43 described above, when the predetermined time T5 has elapsed (YES), the information processing apparatus 6 proceeds to step S44, and calculates the degree of distortion S using the elements of the array PHS. In this case, the degree of distortion S is expressed by the following equation (2), where m is the average of the array PHS (PHS [0], PHS [1],..., PHS [n−1]), and σ is the standard deviation. Calculated by

  The degree of distortion S is a scale indicating the degree to which the data is not distributed around the average, and the value becomes smaller as the data is evenly distributed. In step S45, the calculated degree of distortion S is compared with a predetermined threshold value Sth. If the degree of distortion S exceeds the threshold value Sth (S45: YES), the information processing apparatus 6 determines that there is an insulation abnormality part and proceeds to the insulation abnormality process in step S46. If the degree of distortion S is less than or equal to the threshold value Sth (S45: NO), the process waits until the waiting time T1 elapses in step S47, and then returns to step S41.

  FIG. 10 (a) shows an example of the frequency distribution of the voltage phase at the time of UV detection when creeping discharge is not generated in the transformer 4 (when not discharged), and FIG. 10 (b) shows that creeping discharge occurs. The example of the frequency distribution of the voltage phase at the time of ultraviolet detection in the case of (when discharging) is shown. In this case, the waiting time T1 in step S47 is 10 seconds, and the predetermined time T5 in step S43 is 120 minutes. In general, it is known that creeping discharge occurs when the applied voltage of the electrical equipment (transformer 4) is in the vicinity of the peak, and the voltage phase at the time of detecting the ultraviolet rays is concentrated around 90 degrees and 270 degrees. On the other hand, the voltage phase at the time of UV detection at the time of non-discharge (that is, the applied voltage phase at the time of detecting UV by disturbance light) is evenly distributed from 0 degrees to 360 degrees. If the degree of distortion S is calculated based on the data shown in FIG. 10A (data at the time of non-discharge), it becomes 0.04, and the degree of distortion S is calculated based on the data shown in FIG. 10B (data at the time of discharge). When calculated, it becomes 0.46. Therefore, the presence or absence of discharge can be determined by setting the threshold value Sth to 0.1.

  As described above, in the present embodiment, the voltage phase applied to the transformer 4 at the time of detecting ultraviolet rays is measured, and the voltage phase at the time of detecting ultraviolet rays within a predetermined time T5 is within a specific phase range (near 90 degrees and 270 degrees). It is judged that there is an insulation abnormality location when it is concentrated in the area, so even if it is a weak discharge with the same intensity as the disturbance light, the presence or absence of the insulation abnormality location is detected reliably. Can be determined with high reliability.

(Fifth embodiment)
Next, a fifth embodiment of the present invention will be described with reference to FIGS.
FIG. 11 is a flowchart showing a procedure for diagnosing insulation abnormality in the present embodiment. First, in step S51, the UV detection voltage phase data Pi is acquired from the signal processing circuit 5. Next, in step S52, the ultraviolet detection voltage phase data Pi acquired in step S51 is stored in the array PHS that holds the detection voltage phase. While the predetermined time T6 has not elapsed (step S53: NO) from the calculation of the number of times CP of the specific UV detection voltage phase (see step S54) last time (step S53: NO), the information processing apparatus 6 proceeds to step S57 and waits for Wait until T1 has elapsed (S57: NO), and when the standby time T1 has elapsed (S57: YES), the process returns to step S51.

  In step S53 described above, when the predetermined time T6 has elapsed from the previous calculation of the specific UV detection voltage phase count CP (YES), the information processing apparatus 6 proceeds to step S54, and the elements of the array PHS are voltage peaks. The number of objects in the vicinity (that is, near 90 degrees or 270 degrees) is calculated (counted) as the frequency CP of the specific UV detection voltage phase. The calculated number UV of the voltage phase at the time of UV detection is the number of times UV is detected near the peak of the applied voltage (phase when the amplitude is maximum) within the predetermined time T6 (the number of UV detections near the voltage peak). Indicates. In step S55, the calculated number of times of UV detection voltage phase CP is compared with a predetermined threshold value CPth. If the number of times UV of the specific UV detection voltage phase exceeds the threshold value CPth (S55: YES), it is determined that there is an insulation abnormality part, and the process proceeds to the insulation abnormality process of step S56. If the number CP of the voltage phase at the time of detecting the specific ultraviolet ray is equal to or less than the threshold value CPth (S55: NO), it is determined that there is no insulation abnormality, and after waiting until the standby time T1 elapses in step S57. Return to step S51.

  FIG. 12 shows the number of times that ultraviolet rays are detected in the vicinity of the applied voltage peak when the creeping discharge is not generated in the transformer 4 (at the time of non-discharge) and when the creeping discharge is generated (at the time of discharge). An example of the frequency distribution of the number of times CP of the voltage phase at the time of UV detection is shown. In this case, the waiting time T1 was 10 seconds, and the predetermined time T5 was 10 minutes. The number of UV detection times near the applied voltage peak is concentrated to 4 times or less when not discharged, and 5 times or more when discharged. Therefore, the presence or absence of discharge can be determined by setting the threshold value CPth to 5 times.

  As described above, in the present embodiment, the voltage phase applied to the transformer 4 at the time when ultraviolet rays are detected is measured, and the specific ultraviolet detection voltage phase (90 degrees or around 270 degrees) measured within a predetermined time T6. When the number of times CP exceeds a predetermined threshold value CPth, it is determined that there is an insulation abnormality, so it is possible to reliably detect the occurrence of creeping discharge even with a weak discharge having the same intensity as ambient light. Thus, the presence or absence of an abnormal insulation point can be determined with high reliability.

(Sixth embodiment)
Next, a sixth embodiment of the present invention will be described with reference to FIGS.
FIG. 13 is a flowchart showing a procedure for diagnosing insulation abnormality in the present embodiment. First, in step S61, ultraviolet detection number data Ci is acquired from the signal processing circuit 5, and in step S62, the acquired ultraviolet detection number data Ci is stored in an array CNT that holds the number of ultraviolet detections. Next, in step S63, the ultraviolet detection voltage phase data Pi is acquired, and in step S64, the acquired ultraviolet detection voltage phase data Pi is stored in the array PHS that holds the ultraviolet detection voltage phase. While the predetermined time T7 does not elapse (step S65: NO), the information processing apparatus 6 proceeds to step S72 and waits until the standby time T1 elapses (S72: NO), and when the standby time T1 elapses ( (S72: YES), the process returns to step S61.

  In step S65 described above, when the predetermined time T7 has elapsed (YES), the information processing apparatus 6 calculates the sum of elements of the array CNT, that is, the number of UV detection times CS in step S66. In step S67, an ultraviolet detection time interval is obtained from the array CNT (see FIG. 7), and an average value IM is calculated. In step S68, the number of elements in the array PHS that have a voltage peak vicinity, that is, the number CP of the specific UV detection voltage phase is counted. In step S69, the number of UV detection times CS within the predetermined time T7, the average value IM of the UV detection time intervals measured within the predetermined time T7, and the number CP of the specific UV detection voltage phase measured within the predetermined time T7. , The Mahalanobis distance MD is calculated, and the process proceeds to step S70 to compare the calculated Mahalanobis distance MD with a predetermined threshold value MDth. If the Mahalanobis distance MD is smaller than the threshold value MDth (S70: YES), it is determined that there is an insulation abnormality part, and the process proceeds to an insulation abnormality process in step S71. If the Mahalanobis distance MD is greater than or equal to the threshold value MDth (S70: NO), it is determined that there is no insulation abnormality, and the process waits until the standby time T1 elapses in step S72. Return.

  Here, the Mahalanobis distance will be described. In MT method (Mahalanobis-Taguchi method), which is one of the quality engineering methods used for pattern recognition for prediction and diagnosis, how similar to this reference data group is based on a certain state described in multivariate. A measure that expresses whether or not it takes into account the correlation between variables is called the Mahalanobis distance. In the present embodiment, the number of UV detection times CS within a predetermined time T7, the average value IM of the UV detection time intervals measured within the predetermined time T7, and the specific measurement measured within the predetermined time T7 in a state where discharge is occurring. The number of times CP of the voltage phase during UV detection is calculated, and a set of data with these values as variables is used as a reference data group.

A procedure for calculating the Mahalanobis distance using the reference data group will be described.
FIG. 14 shows the variable 1, variable 2, and variable 3 as the number of UV detections CS, the average value IM of UV detection time intervals, and the number CP of specific UV detection voltage phases calculated (measured) within a predetermined time T7, respectively. A reference data group is shown. Here, averages m1 to m3 of variables 1 to 3 and standard deviations σ1 to σ3 are calculated for the prepared n pieces of reference data.

Subsequently, each element yi1, yi2, yi3 (i = 1, 2,..., N) of the n reference data is normalized by the following equation (3) using averages m1 to m3 and standard deviations σ1 to σ3. Turn into. FIG. 15 shows a reference data group with normalized elements Yi1, Yi2, Yi3 (i = 1, 2,..., N).

A correlation coefficient is calculated from the normalized variables shown in FIG. 15, and a correlation coefficient matrix R shown in Expression (4) is created.

  Here, since there are three variables, the correlation coefficient matrix R is a 3 × 3 matrix. Expression (5) is an expression for deriving the element rpq (= rqp) of the correlation coefficient matrix R.

Subsequently, an inverse matrix R ⁻¹ of the correlation coefficient matrix R shown in Expression (6) is calculated.

Expression (7) represents the determinant | R | of the correlation coefficient matrix R. The Mahalanobis distance MD includes a variable number (here, 3), a certain normalized UV detection count CS, UV detection time interval average value IM, specific UV detection voltage phase count CP data, and inverse matrix R. ^-1 is used to calculate the following equation (8).

  As the calculated Mahalanobis distance MD is smaller, it means that it is closer to the reference data group, and it can be determined that discharge has occurred.

  FIG. 16 shows a reference data group (average number of UV detection times CS and UV detection time interval) when no creeping discharge occurs in the transformer 4 (when not discharging) and when creeping discharge occurs (when discharging). This is an example in which the Mahalanobis distance MD is calculated from the value IM and the specific UV detection voltage phase count CP). In this case, the waiting time T1 was 10 seconds, and the predetermined time T7 was 10 minutes. The Mahalanobis distance MD at the time of discharge is concentrated in the vicinity of 0, and the Mahalanobis distance MD at the time of non-discharge is distributed to 5 or more. Accordingly, in this example, by setting the threshold value MDth to 5, it can be determined that there is a discharge when the Mahalanobis distance is less than 5, and there is no discharge when the distance is 5 or more.

  As described above, in the present embodiment, the number of detection times of ultraviolet rays, the time interval at which the ultraviolet rays are detected, and the voltage phase applied to the transformer 4 when the ultraviolet rays are detected are measured, and the number of detection times of ultraviolet rays CS within a predetermined time. And calculating the Mahalanobis distance MD using the average value IM of the UV detection time intervals measured within the predetermined time and the number of times CP of the specific UV detection voltage phase measured within the predetermined time as variables. When the Mahalanobis distance MD is smaller than the predetermined threshold value MDth, it is determined that there is an abnormality in insulation. Therefore, whether or not creeping discharge has occurred is surely detected even with a weak discharge having the same intensity as disturbance light. By detecting it, it is possible to determine with high reliability the presence or absence of an insulation abnormality.

  In the present embodiment, the number of UV detection times CS during discharge, the average value IM of UV detection time intervals, and the number CP of specific UV detection voltage phases are used as reference data. The average value IM of the UV detection time intervals and the number CP of the specific UV detection voltage phase may be used as reference data. In this case, when the calculated Mahalanobis distance MD is greater than or equal to the threshold value MDth, it can be determined that a discharge has occurred.

(Other embodiments)
In addition, this invention is not limited to each embodiment shown above and shown in drawing, For example, it can deform | transform or expand as follows.
The UV detection frequency data Ci and the UV detection voltage phase data Pi acquired at each standby time T1 are stored (stored) in a file, and after the measurement time, the same insulation abnormality diagnosis is performed using the data stored in the file. May be performed.

A configuration may be adopted in which the cumulative detection frequency data Cs is stored in the detection frequency data memory 7 and the ultraviolet detection frequency data Ci is acquired using the cumulative detection frequency data Cs.
The waiting time T1 and the predetermined times T2 to T7 can be changed as appropriate.

The block diagram which shows the insulation abnormality diagnostic apparatus of this invention The flowchart which shows the control content of the insulation abnormality diagnosis of the 1st Embodiment of this invention. (A) is the time of non-discharge, (b) is a figure which shows the example of the cumulative detection frequency at the time of discharge. FIG. 2 equivalent view showing the second embodiment of the present invention The figure which shows the example of the frequency distribution of the number of times of ultraviolet-ray detection for 10 minutes at the time of non-discharge and discharge FIG. 2 equivalent view showing the third embodiment of the present invention The figure for demonstrating the production | generation method of array INT The figure which shows the example of frequency distribution of the ultraviolet detection time interval at the time of non-discharge and discharge FIG. 2 equivalent view showing a fourth embodiment of the present invention (A) is the time of undischarge, (b) is a figure which shows the example of frequency distribution of the voltage phase at the time of ultraviolet detection at the time of discharge FIG. 2 equivalent view showing a fifth embodiment of the present invention The figure which shows the example of the frequency distribution of the frequency | count which detected the ultraviolet-ray in the vicinity of an applied voltage peak at the time of undischarge and discharge FIG. 2 equivalent view showing a sixth embodiment of the present invention Diagram showing reference data group before normalization Diagram showing standard data group after normalization The figure which shows the distance of Mahalanobis calculated from the reference data group at the time of non-discharge and discharge This figure is used for explanation of the prior art, and (a) a waveform showing a current waveform flowing in a ground line when a discharge occurs, and (b) a waveform showing an AC voltage waveform applied to electrical equipment.

Explanation of symbols

  In the drawings, 1 is an insulation abnormality diagnosis device, 2 is an ultraviolet sensor (ultraviolet detection means), 3 is a signal processing device (determination means, measurement means, detection frequency measurement means, time interval measurement means, voltage phase measurement means, Mahalanobis distance calculation. Means), 4 is a transformer (electrical equipment), and 6 is an information processing apparatus.

Claims (10)

A method for diagnosing an insulation abnormality in an electrical facility that determines the presence or absence of an insulation abnormality location by detecting ultraviolet rays radiated along with a creeping discharge generated on the surface of the electrical facility in operation,
A method for diagnosing an insulation abnormality in electrical equipment, wherein the number of times of cumulative detection of ultraviolet rays is measured, and when an inclination of the cumulative number of detections within a predetermined time exceeds a predetermined threshold, it is determined that an insulation abnormality location exists. A method for diagnosing an insulation abnormality in an electrical facility that determines the presence or absence of an insulation abnormality location by detecting ultraviolet rays radiated along with a creeping discharge generated on the surface of the electrical facility in operation,
The time interval at which ultraviolet rays are detected is measured, and when the ultraviolet ray detection time intervals measured within a predetermined time are concentrated and distributed in a specific interval range, it is determined that there is an insulation abnormality part . Insulation abnormality diagnosis method. A method for diagnosing an insulation abnormality in an electrical facility that determines the presence or absence of an insulation abnormality location by detecting ultraviolet rays radiated along with a creeping discharge generated on the surface of the electrical facility in operation,
Measure the applied voltage phase of the electrical equipment at the time of detecting the ultraviolet ray, and determine that there is an insulation abnormality location when the ultraviolet detection voltage phase measured within a predetermined time is concentrated and distributed in a specific phase range An insulation abnormality diagnosis method for electrical equipment, characterized by: A method for diagnosing an insulation abnormality in an electrical facility that determines the presence or absence of an insulation abnormality location by detecting ultraviolet rays radiated along with a creeping discharge generated on the surface of the electrical facility in operation,
Measures the voltage phase applied to the electrical equipment at the time of detecting ultraviolet rays, and determines that there is an abnormal insulation location when the number of times of the specific ultraviolet detection voltage phase measured within a specified time exceeds a specified threshold value. An insulation abnormality diagnosis method for electrical equipment, comprising: A method for diagnosing an insulation abnormality in an electrical facility that determines the presence or absence of an insulation abnormality location by detecting ultraviolet rays radiated along with a creeping discharge generated on the surface of the electrical facility in operation,
Measure the number of detection times of ultraviolet rays, the time interval when ultraviolet rays were detected, and the applied voltage phase of the electrical equipment at the time of detecting ultraviolet rays,
The Mahalanobis distance calculated using the number of UV detection times within a predetermined time, the UV detection time interval measured within the predetermined time, and the number of specific UV detection voltage phases measured within the predetermined time as variables An insulation abnormality diagnosis method for electrical equipment, wherein the presence or absence of an insulation abnormality part is determined by comparing with a threshold value . Ultraviolet detecting means for detecting ultraviolet rays radiated along with creeping discharge generated on the surface of the electrical equipment in operation, and judging means for judging the presence or absence of an insulation abnormality by detecting the ultraviolet rays by the ultraviolet detecting means. An insulation abnormality diagnosis device for electrical equipment provided,
Measuring means for measuring the cumulative number of detection times of ultraviolet rays detected by the ultraviolet detection means,
The determining means, the slope of the cumulative number of times of detection in the measuring means a predetermined time of the electrical equipment, characterized in that it is determined that the insulation abnormality location is present if it exceeds a predetermined threshold insulation abnormality diagnosis device . Ultraviolet detecting means for detecting ultraviolet rays radiated along with creeping discharge generated on the surface of the electrical equipment in operation, and judging means for judging the presence or absence of an insulation abnormality by detecting the ultraviolet rays by the ultraviolet detecting means. An insulation abnormality diagnosis device for electrical equipment provided,
A measuring means for measuring a time interval at which the ultraviolet ray detecting means detects the ultraviolet ray;
The determination means determines that there is an abnormal insulation location when the UV detection time intervals measured within a predetermined time by the measurement means are concentrated in a specific interval range. Abnormality diagnosis device. Ultraviolet detecting means for detecting ultraviolet rays radiated along with creeping discharge generated on the surface of the electrical equipment in operation, and judging means for judging the presence or absence of an insulation abnormality by detecting the ultraviolet rays by the ultraviolet detecting means. An insulation abnormality diagnosis device for electrical equipment provided,
A measuring means for measuring the applied voltage phase of the electrical equipment at the time when the ultraviolet detecting means detects the ultraviolet light,
The determination means determines that an insulation abnormality location exists when the voltage phase at the time of ultraviolet detection measured by the measurement means within a predetermined time is concentrated and distributed in a specific phase range . Insulation abnormality diagnosis device. Ultraviolet detecting means for detecting ultraviolet rays radiated along with creeping discharge generated on the surface of the electrical equipment in operation, and judging means for judging the presence or absence of an insulation abnormality by detecting the ultraviolet rays by the ultraviolet detecting means. An insulation abnormality diagnosis device for electrical equipment provided,
A measuring means for measuring the applied voltage phase of the electrical equipment at the time when the ultraviolet detecting means detects the ultraviolet light,
The determination means determines that an insulation abnormality portion exists when the number of times of a specific UV detection voltage phase measured within a predetermined time by the measurement means exceeds a predetermined threshold value. Equipment insulation abnormality diagnosis device. Ultraviolet detecting means for detecting ultraviolet rays radiated along with creeping discharge generated on the surface of the electrical equipment in operation, and judging means for judging the presence or absence of an insulation abnormality by detecting the ultraviolet rays by the ultraviolet detecting means. An insulation abnormality diagnosis device for electrical equipment provided,
A detection frequency measuring means for measuring the number of times of detection of ultraviolet rays by the ultraviolet light detection means;
A time interval measuring means for measuring a time interval when the ultraviolet ray detecting means detects the ultraviolet ray; and
Voltage phase measuring means for measuring the applied voltage phase of the electrical equipment at the time when the ultraviolet ray detecting means detects ultraviolet rays;
The number of UV detection times measured within a predetermined time by the detection number measuring means, the UV detection time interval measured within a predetermined time by the time interval measuring means, and the voltage phase measuring means measured within a predetermined time A Mahalanobis distance calculating means for calculating the Mahalanobis distance using the number of times of a specific UV detection voltage phase as a variable,
The determination means determines the presence / absence of an insulation abnormality portion by comparing the Mahalanobis distance calculated by the Mahalanobis distance calculation means with a predetermined threshold value .

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