JP6164022B2 - Interlayer insulation diagnosis method for winding equipment - Google Patents

Description

  The present invention relates to a winding interlayer insulation diagnosis method for diagnosing the winding interlayer insulation of winding equipment such as a rotating machine and a transformer.

  As a main factor of failure of winding equipment such as a rotating machine and a transformer, for example, there is a burnout accident caused by dielectric breakdown between winding layers of the winding equipment.

  The winding layers are electrically at the same potential, and no voltage is applied between the winding layers. Therefore, basically, no electrical breakdown occurs between the winding layers. However, it is well known that a high voltage is instantaneously applied between winding layers due to a surge generated when starting a winding device or operating a circuit breaker provided in the winding device. For this reason, when the dielectric strength between winding layers falls, a dielectric breakdown between winding layers will be caused by a surge, and there exists a possibility of causing the burning of a winding apparatus.

  In recent years, with the spread of inverter equipment, the stress applied between the winding layers has increased, and the importance of the insulation between the winding layers has further increased. With such an increase in stress applied between the winding layers, attention has been paid to a diagnostic technique for insulating properties between the winding layers.

  Generally, in the field of maintenance / maintenance (maintenance) of rotating equipment, insulation diagnosis between winding layers is performed by detecting and evaluating an electrical signal when an AC voltage is applied to the winding equipment (for example, patents) Literature 1-8). In particular, in the insulation diagnosis between winding layers, evaluation of partial discharge generated when a voltage is applied is considered to be most important. As described above, since the voltage between the winding layers is the same, no voltage is applied and the conventional insulation diagnosis method cannot be applied. For this reason, as a method of diagnosing the insulation between the winding layers, an impulse voltage is applied to the windings to generate a partial discharge between the winding layers, or the insulation deterioration between the winding layers during driving of the winding equipment. A method of detecting an abnormal current caused by the above, and a method of detecting a frequency function of a transfer function or impedance of an insulating layer of a winding are applied.

JP2013-88251A JP 2002-62330 A Japanese Patent Laid-Open No. 2004-45307 JP 2005-309616 A JP 2007-47184 A JP 2009-294129 A JP 2012-149971 A JP 2006-38688 A

  However, each of these methods for diagnosing insulation between winding layers has its own problems. For example, in the insulation diagnosis method using an impulse voltage, a voltage that generates a partial discharge is applied between the winding layers, and thus it is necessary to increase the power supply voltage value to some extent. For this reason, there is a risk of damaging the winding device itself, or in the case where the dielectric strength between the winding layers is remarkably lowered, there is a risk of causing dielectric breakdown by performing an insulation diagnosis. Furthermore, when a discharge occurs, it may be difficult to determine whether the discharge generation site is between the winding layers or between the ground. In the method of detecting abnormal current due to deterioration between winding layers, it is possible to detect that an abnormality has occurred between winding layers by detecting abnormal current, but to maintain and maintain the winding equipment. It may be difficult to apply in some cases. In addition, the method of detecting the frequency characteristic of the transfer function or impedance of the winding insulation layer has a problem that it is necessary to distinguish between the signal used for diagnosis and the noise detected according to the measurement environment, and it is more accurate. Therefore, there is a need for a method for diagnosing winding interlayer insulation that is high in length.

  In other words, when diagnosing the insulation between winding layers, it is difficult to acquire signals by applying an AC voltage as in the past, and when applying a method of applying a voltage between winding layers, It is necessary to consider the effects of damage and noise.

  In view of the above circumstances, an object of the present invention is to provide a winding interlayer insulation diagnosis method for a winding device that contributes to reducing damage to the winding device and the influence of noise.

  One aspect of a winding interlayer insulation diagnosis method for a winding device of the present invention that achieves the above object is a winding interlayer insulation diagnosis method for diagnosing the insulation between winding layers of a winding device, and includes a main insulation in advance. A threshold value is set for the amount of increase in the dielectric tangent of the main insulation, which is an index for evaluating the insulation, and the amount of increase in the dielectric tangent of the main insulation of the winding device to be diagnosed is obtained. The insulation between the winding layers of the winding device is diagnosed by comparing with a threshold value.

  In addition, another aspect of the winding interlayer insulation diagnosis method for a winding device of the present invention that achieves the above object is the above-described winding interlayer insulation diagnosis method for a winding device. When the insulation between the winding layers is diagnosed as compared with the threshold, and further, the insulation between the winding layers of the winding equipment diagnosed as the insulation between the winding layers is reduced. It is characterized by direct diagnosis of insulation.

  In another aspect of the winding interlayer insulation diagnosis method for a winding device of the present invention that achieves the above object, in the winding interlayer insulation diagnosis method for the winding device, an impulse voltage is applied to the winding. A discharge electromagnetic wave generated between the winding layers when a voltage is applied is detected, and the insulation between the winding layers is directly diagnosed based on the detected discharge electromagnetic wave.

  Another aspect of the winding interlayer insulation diagnosis method for a winding device according to the present invention that achieves the above object is to provide a frequency characteristic of the winding impedance of the winding in the winding interlayer insulation diagnosis method for the winding device. The measurement is performed, and the insulation between the winding layers is directly diagnosed based on the measured frequency characteristic of the winding impedance.

  Another aspect of the winding interlayer insulation diagnosis method for a winding device of the present invention that achieves the above object is the method for measuring the frequency characteristics of the winding impedance in the winding interlayer insulation diagnosis method for the winding device. And correcting based on an index for evaluating the main insulation of the winding device, and diagnosing the insulation between the winding layers based on the measurement result of the frequency characteristics of the corrected winding impedance. .

  According to the above invention, in the winding interlayer insulation diagnosis method for diagnosing the winding interlayer insulation of the winding equipment, it is possible to contribute to the reduction of damage to the winding equipment and the influence of noise.

It is explanatory drawing explaining the outline | summary of the winding interlayer insulation diagnostic method of the winding equipment of this invention. (A) The expanded sectional view of the coil | winding part of a coil | winding apparatus, (b) The schematic diagram of the coil | winding part of a coil | winding apparatus. It is a characteristic view which shows the change of (DELTA) tan (delta) of the main insulation (between ground) and winding interlayer insulation with respect to deterioration time. FIG. 6 is a characteristic diagram showing a relationship between Δtan δ of main insulation and a winding interlayer residual breakdown voltage. FIG. 7 is a characteristic diagram showing a relationship between winding interlayer residual breakdown voltage (when Δtan δ of the main insulation is the same) with respect to deterioration time. It is the schematic of the winding interlayer insulation diagnostic system which diagnoses the winding interlayer insulation of a winding apparatus directly. It is a figure which shows the result of having simulated the voltage shared by each coil | winding when an impulse voltage is applied to a coil | winding. It is a figure which shows the measurement result of the discharge start voltage of the main insulation in each winding apparatus, and the discharge start voltage between winding layers. It is a characteristic view which shows the change of the winding impedance with respect to the applied power supply frequency, and an electrostatic capacitance. It is a characteristic view showing the relationship between the shift rate of the peak frequency of winding impedance and the winding interlayer residual breakdown voltage.

  A winding interlayer insulation diagnosis method for a winding device according to an embodiment of the present invention will be described in detail with reference to the drawings.

  A winding interlayer insulation diagnosis method for a winding device according to an embodiment of the present invention evaluates insulation between winding layers based on a diagnostic parameter for evaluating insulation of main insulation of the winding device. The cause of insulation deterioration of the winding equipment is mainly a thermal factor, an electrical factor, a mechanical factor, and an environmental factor, and it is said that the thermal factor is particularly dominant. The thermal stress level is affected by operating conditions and aging time, and it is considered that deterioration progresses according to the aging time of the main insulation and the winding interlayer insulation. Therefore, among the diagnostic parameters for evaluating the insulation of the main insulation of the winding device, parameters due to thermal factors are selected, and the dielectric strength between the winding layers is evaluated based on the selected parameters. Examples of the parameter resulting from the thermal factor include a dielectric tangent of main insulation and a capacitance.

  As shown in FIG. 1, the winding interlayer insulation diagnosis method for a winding device according to an embodiment of the present invention diagnoses the insulation of the main insulation of the winding device and uses diagnostic parameters for diagnosing the insulation of the main insulation. A parameter caused by a thermal factor is selected from the inside, and the insulation between the winding layers is diagnosed using this parameter (STEP 1). In this diagnostic method, since the insulation state between the winding layers is estimated based on the diagnostic parameter of the main insulation, the insulation between the winding layers can be diagnosed without performing the insulation diagnosis directly on the winding layers. it can.

  Further, in another aspect of the winding interlayer insulation diagnosis of the winding device according to the embodiment of the present invention, the insulating property between the winding layers is lowered in STEP 1 (the insulating layer between the winding layers is deteriorated). Further, the insulation between the winding layers is directly diagnosed for the winding device determined to be (STEP 2). In this diagnosis method, the insulation state between the winding layers can be diagnosed in more detail by performing STEP2. In STEP 1, since the insulation state between the winding layers is estimated in advance, the number of times of directly diagnosing the insulation between the winding layers can be reduced, and the insulation diagnosis work of the winding device can be simplified.

  The winding interlayer insulation diagnosis method for a winding device of the present invention will be described below in detail with specific embodiments.

[First Embodiment]
The winding interlayer insulation diagnosis method for a winding device according to the first embodiment of the present invention diagnoses the insulation of the main insulation of the winding device, and determines the thermal factor from among the diagnostic parameters for diagnosing the insulation of the main insulation. The parameter (dielectric loss tangent) resulting from the above is selected, and the insulation between the winding layers is diagnosed using this parameter.

  For example, a sine wave voltage, a superimposed voltage of a sine wave voltage and an impulse voltage, or an impulse voltage is applied to the winding device to be diagnosed.

  For example, in the diagnostic field of a high-voltage rotating machine with a rating of 3 kV or higher, the test voltage is 1 / √3 times the device rated voltage or 1 / √3 × 1.25 times the rated voltage. The quality of the device is determined from the diagnostic parameters (for example, the presence or absence of dielectric loss tangent or partial discharge). That is, when diagnosing a 6.6 kV rotating machine, a test voltage of about 3.8 kV or 4.8 kV is applied.

  Next, the insulation between the winding layers is diagnosed based on a characteristic value (for example, dielectric loss tangent or the like) that determines the degree of deterioration caused by a thermal factor. If the diagnostic parameters for judging the quality of the equipment and the diagnostic parameters for diagnosing the insulation between the winding layers are the same, measuring the same diagnostic parameters, Diagnosis of insulation between layers can be performed. In addition, when the diagnostic parameter for judging the quality of the equipment is different from the diagnostic parameter for diagnosing the insulation between the winding layers, the judgment of the quality of the equipment and the winding layers are determined based on the measured diagnostic parameters. Diagnosis of insulation is performed.

[Evaluation of insulation between main insulation and winding layers]
First, the insulation characteristics of the main insulation of the model coil and the insulation characteristics between the winding layers of the model coil were measured using a model coil that was accelerated and deteriorated in a high temperature environment. The main insulation of the model coil (winding device) is, for example, the insulation characteristic of the ground-main insulating layer 4 provided so as to cover the outer periphery of the coil as shown in FIG. Moreover, the insulation characteristic between winding layers is the insulation characteristic of the interlayer insulation 3 of the coil | winding (the electric wire 1 and the coating layer 2 of the electric wire 1) wound around the iron core, for example. Note that the voltage sharing ratio of the windings in the winding device is not uniform among the windings, and the first coil (first pole) closest to the motor terminal as shown in FIG. 2B has a large voltage sharing ratio. It is known that Therefore, when evaluating the voltage sharing ratio and the insulation characteristics, the voltage sharing ratio and the insulation characteristics between the first coil (first pole) and the second coil (second pole) adjacent to the first coil. Evaluate.

  The evaluation of the main insulation and the winding interlayer insulation was performed based on the increase of the dielectric loss tangent (Δtan δ) by calculating the dielectric loss tangent (tan δ) between the main insulation and the winding interlayer.

  Tan δ can be measured, for example, directly with an LCR meter or using a bridge circuit. Δtan δ is obtained when a dielectric tangent (tan δ) when a predetermined reference voltage (for example, 1 kV or 2 kV) is applied and a test voltage (for example, 1 / √3 of the rated voltage) is applied. Is calculated by the difference from tan δ.

  FIG. 3 is a diagram illustrating a change in Δtan δ of the sample with respect to the accelerated deterioration time. As samples for determining the degree of deterioration between winding layers, three samples deteriorated under the same deterioration conditions were prepared, and the degree of deterioration between winding layers was determined. As shown in FIG. 3, Δtan δ showed an increasing tendency with respect to the deterioration time in both cases of determining the degree of deterioration of the main insulation (between ground) and determining the degree of deterioration between the winding layers. . The change in Δtanδ of the main insulation and the change in Δtanδ between the winding layers have a certain degree of correlation, and the deterioration degree of the winding interlayer insulation is based on Δtanδ, which is an index for determining the deterioration degree of the main insulation. Can be estimated.

  Note that Δtan δ of the undegraded product between the winding layers is larger than that of the sample deteriorated for five years. This is because the polymer (resin) impregnated in the rotating machine adheres to the coil surface. The reason for this is that a current path is created. Since this polymer penetrates the entire device due to heat during operation, it is considered that the influence of the polymer is reduced with deterioration.

  FIG. 4 is a diagram showing the relationship between the value of Δtan δ of the main insulation of the winding device and the inter-winding layer residual breakdown voltage. Δtan δ of the main insulation was obtained by applying a normal ground voltage (voltage applied between the circuit of the main circuit and the ground in a normal operation state) to the winding of the winding device. The residual breakdown voltage is the ratio of the breakdown voltage after deterioration to the breakdown voltage before deterioration, and indicates the inter-winding breakdown value.

  As shown in FIG. 4, when the increase amount (Δtan δ) of the dielectric tangent of the main insulation when the normal ground voltage is applied is 1.0 or more, the value of the inter-winding layer residual breakdown voltage decreases. This indicates that it is possible to evaluate the winding interlayer insulation based on the non-destructive diagnostic parameter (Δtan δ) of the main insulation.

  FIG. 5 is a diagram showing a result of measuring the inter-winding layer residual breakdown voltage in an initial deterioration sample and an aged deterioration sample in which Δtan δ shows the same value. As shown in FIG. 5, a sample having a small value of Δtanδ (Δtanδ = 0.4), a sample having a large value of Δtanδ (Δtanδ = 2), regardless of whether the sample is initially deteriorated or aged. .0) is less likely to cause dielectric breakdown between windings. However, even if the value of Δtan δ is the same (for example, Δtan δ = 2.0), the sample with aged deterioration has a higher possibility of the winding interlayer dielectric breakdown than the sample with the initial deterioration. Therefore, even if Δtan δ is small, a winding device having a long period of use may cause a dielectric breakdown between windings. For example, for a winding device having a history of use for more than 50 years and remarkable deterioration over time, Even if the value of Δtanδ is small, it is necessary to consider the possibility of dielectric breakdown between windings.

  Next, for the above diagnostic method, Bayes' theorem was applied, and the probability that a decrease in insulation (deterioration degree) between winding layers could be detected from Δtanδ of the main insulation was obtained. The basic formula of Bayes' theorem is shown in Equation 1.

  Table 1 shows the result of analyzing the results of the diagnosis of the insulation properties of the main insulation and the winding interlayer insulation obtained experimentally by Bayes' theorem.

P (H1 | D): Probability that the winding interlayer insulation is deteriorated under the condition of Δtanδ ≧ 1 P (H1): Prior probability that deterioration of the winding interlayer insulation is confirmed: 0.25
P (H2): Prior probability that deterioration of winding interlayer insulation was not confirmed: 0.75
P (D | H1): Probability that Δtanδ ≧ 1 and the winding interlayer insulation is deteriorated under the condition that the deterioration of the winding interlayer insulation is confirmed with the prior probability: 0.33
P (D | H2): Probability of Δtanδ ≧ 1 and deterioration of winding interlayer insulation under the condition that deterioration of winding interlayer insulation is not confirmed with prior probability: 0.67
As shown in Equation 2, by substituting the values shown in Table 1 into the Bayes' theorem shown in Equation 1, deterioration of the winding interlayer insulation can be detected under the condition of Δtanδ ≧ 1 of the main insulation. Probability was calculated.

  In the experiment, 71% of the samples satisfying Δtanδ ≧ 1.0 of the main insulation, and among them, the possibility of detecting a confirmed decrease in the winding interlayer dielectric breakdown value was 33%. The probability that the winding interlayer insulation is deteriorated when Δtanδ ≧ 1.0 of the main insulation calculated based on Bayes' theorem is about 14%.

[Insulation diagnosis of winding equipment actually operated]
With the winding interlayer insulation diagnosis method for a winding device according to the first embodiment, a diagnosis was made on a winding device that is actually operating (rated voltage = 6 kV, aging time = about 15 years).

  When Δtan δ of the main insulation of the target device was measured, it was 0.8, and the discharge electromagnetic wave due to the impulse voltage application was not detected. When the insulation characteristic measurement result of the main insulation is applied to the winding interlayer insulation diagnosis of the first embodiment and the diagnosis between the winding layers of the target device is performed, the Δtanδ of the main insulation of the target winding device is more than 1.0. Since it is small, the inter-winding insulation is diagnosed as sound.

  In order to confirm this diagnosis result, when an impulse voltage of about 5 times the rated voltage was actually applied between the winding layers, dielectric breakdown did not occur between the winding layers. As described above, it was confirmed that the winding interlayer insulation of the winding device can be evaluated based on the insulation characteristic diagnosis parameter of the main insulation of the winding device.

  According to the winding interlayer insulation diagnosis method for a winding device according to the first embodiment of the present invention as described above, by evaluating the insulation characteristics between the winding layers based on the diagnostic parameter of the main insulation, It is possible to easily evaluate the deterioration state of the.

  That is, the winding interlayer insulation diagnosis method for a winding device according to the first embodiment of the present invention focuses on the fact that the same thermal stress is applied to the main insulation of the winding device and the winding interlayer insulation. The insulation between winding layers is evaluated based on a diagnosis parameter (for example, Δtan δ) due to a thermal factor among parameters for performing insulation diagnosis. As a result, for example, when Δtan δ of the main insulation at the time of normal ground voltage application exceeds a predetermined reference value of caution, it is determined that the dielectric strength between the winding layers is similarly lowered to a dangerous level. It is possible. Even if it is determined that Δtanδ of the main insulation is healthy, it can be determined that the dielectric strength between the winding layers is reduced if the operation history is sufficiently long.

  In addition, since the insulation characteristics between the winding layers are evaluated based on the diagnostic parameters for diagnosing the insulation of the main insulation, damage to the windings and the like due to the separate insulation diagnosis between the winding layers can be eliminated. .

  In addition, by using a data analysis method based on probability and statistics such as Bayes' theorem, it is possible to make a diagnosis taking into account multiple factors, and the accuracy of insulation evaluation between winding layers is improved. For example, in addition to main insulation diagnosis data, equipment operation history, detection of discharge electromagnetic waves when impulse voltage is applied to the winding, frequency characteristics data of winding impedance, temperature / humidity data of equipment usage environment, equipment load factor, etc. Is incorporated into the Bayes' theorem and analyzed, so that the insulation diagnosis accuracy between the winding layers can be improved.

[Second Embodiment]
In the winding interlayer insulation diagnosis method for a winding device according to the second embodiment of the present invention, the insulation between winding layers is reduced in the winding interlayer insulation diagnosis method for a winding device according to the first embodiment. The insulation between the winding layers is directly diagnosed for the determined winding equipment.

  In the winding interlayer insulation diagnosis method for a winding device according to the second embodiment, the insulation characteristic between winding layers is diagnosed based on the diagnostic parameter of the main insulation as shown in FIG. 1 (STEP 1). Then, for the winding device evaluated as having deteriorated the insulation characteristics between the winding layers by this diagnosis, the discharge start voltage measurement between the winding layers is further performed to directly diagnose the insulation between the winding layers ( (Step 2).

  Note that the diagnosis procedure of STEP 1 of the winding interlayer insulation diagnosis method for a winding device according to the second embodiment is the same as that of the winding interlayer insulation diagnosis method for the winding device according to the first embodiment. Therefore, in the following description, the diagnosis procedure of STEP 2 that is not explained in the winding interlayer insulation diagnosis method for the winding device according to the first embodiment will be described in detail.

  FIG. 6 is a diagram showing an outline of a winding interlayer insulation diagnosis system 7 used in the STEP2 diagnosis procedure of the winding interlayer insulation diagnosis method for winding equipment according to the second embodiment of the present invention. The winding interlayer insulation diagnosis system 7 applies an impulse voltage to the winding 9 of the winding device 8 and detects a discharge electromagnetic wave generated between the windings 9 to diagnose the insulation characteristics between the winding layers.

  As shown in FIG. 6, the winding interlayer insulation diagnosis system 7 includes an impulse voltage application device 10 and a discharge electromagnetic wave detection device 11.

  The impulse voltage application device 10 applies an impulse voltage to the winding 9 of the winding device 8. When an impulse voltage is applied to the winding 9, if this value is too large, the winding device 8 is not only damaged, but also a discharge electromagnetic wave is generated from the ground, making it difficult to specify the discharge generation site. Therefore, the impulse voltage application device 10 applies to the winding device 8 an impulse voltage that generates a discharge electromagnetic wave between the windings 9 and does not generate a discharge electromagnetic wave in the main insulation (between ground). For example, an impulse voltage of 3 kV or less is applied to the winding 9 of the winding device 8.

  The condition under which the partial discharge does not occur due to the main insulation is set using, for example, an actual measurement value with a model coil. That is, the electromagnetic wave when the impulse voltage is applied to the model coil is detected by the sensor, and the lowest voltage value at which the electromagnetic wave is detected is investigated. Since the model coil is a single coil used in an actual device, a voltage value at which no discharge occurs in the model coil can be regarded as a voltage at which no discharge occurs in the actual device. According to this method, it is possible to determine a condition in which partial discharge does not occur due to main insulation even for winding devices having different ratings.

  The discharge electromagnetic wave detection device 11 includes an electromagnetic wave sensor 12 for detecting a discharge electromagnetic wave generated between the windings 9, a log amplifier 13 for amplifying a signal received by the electromagnetic wave sensor 12, and a discharge electromagnetic wave from the signal amplified by the log amplifier 13. And a detection device 15 for detecting a partial discharge between the windings 9 based on the signal detected by the electromagnetic wave sensor. Discharge electromagnetic waves generated between the winding 9 layers are received by the electromagnetic wave sensor 12 and input to the detection device 15 via the log amplifier 13 and the high-pass filter 14.

  As shown in FIG. 2B, when an impulse voltage is applied to the winding device 8, 60% to 80% of the applied voltage is applied to the first coil (first pole) that is said to be most deteriorated. Is done. As shown in FIG. 7, when the voltage assigned to each winding 9 is simulated, when an impulse voltage is applied to the coil, the voltage assigned to each winding 9 is the first coil closest to the motor terminal (first coil). The closer to the pole, the larger.

[Evaluation of insulation between winding layers]
In the winding interlayer insulation diagnosis method for a winding device according to the second embodiment, first, the insulation of the main insulation is evaluated, and the insulation between the winding layers is evaluated using diagnostic parameters for evaluating the insulation of the main insulation. Is evaluated (STEP 1). Then, an impulse voltage is applied to the windings of the winding equipment evaluated as having deteriorated insulation between the winding layers in STEP 1, and a discharge start voltage generated between the winding layers is measured to insulate the winding layers. Sex is diagnosed directly (STEP2).

  In FIG. 8, the impulse voltage is applied to each winding device (model coil) with different deterioration levels, and the value of the discharge start voltage is measured between the main insulation and the winding layer (between the first and second poles). The results are shown. When measuring the discharge start voltage of the main insulation, the impulse voltage was applied between the winding and the iron core.

  When measuring the discharge start voltage when performing insulation diagnosis between winding layers, if the applied impulse voltage is larger than the discharge start voltage of the main insulation, partial discharge occurs between the ground and insulation from the partial discharge generated between the ground. Discrimination from partial discharge generated between layers becomes difficult. Therefore, if the discharge start voltage between the winding layers can be measured under the condition that the partial discharge does not occur in the main insulation, it is possible to suppress the damage to the winding device and perform an accurate insulation diagnosis between the winding layers. It can be carried out.

  As shown in FIG. 8, the discharge start voltage between the winding layers is lower than the discharge start voltage of the main insulation. Therefore, in the inter-winding insulation diagnosis method of the second embodiment, the impulse voltage applied to the winding in the insulation diagnosis (STEP 2) between the inter-winding layers is set to a magnitude that does not cause partial discharge in the main insulation (between ground). Thus, the discharge start voltage between the winding layers is measured under the condition that the generation of the partial discharge in the main insulation is suppressed. Then, a threshold value is set for the discharge start voltage between the winding layers, and when the measured discharge start voltage falls below the threshold value, it is evaluated that the insulation between the winding layers is lowered. For example, in the example shown in FIG. 8, the magnitude of the impulse voltage applied to the winding is set to 3.0 kV or less, and the threshold value of the discharge start voltage is set to 1.0 kV.

  In the winding interlayer insulation diagnosis method for a winding device according to the second embodiment of the present invention as described above, the insulation between the winding layers is evaluated based on the diagnostic parameter for diagnosing the insulation of the main insulation, and The insulation breakdown voltage between the winding layers of the winding equipment that is judged to have deteriorated by the evaluation is measured directly and the insulation between the winding layers is directly diagnosed.

  That is, the winding interlayer insulation diagnosis method for a winding device according to the second embodiment of the present invention focuses on the fact that the discharge start voltage between the winding layers decreases as the deterioration between the winding layers proceeds. The insulation between the winding layers is directly diagnosed based on the dielectric breakdown voltage between the layers.

  The inter-winding layer insulation diagnosis method according to the second embodiment of the present invention estimates the insulation state between the winding layers based on diagnostic parameters for diagnosing the insulation of the main insulation in advance. Direct diagnosis between winding layers that may cause damage to the winding equipment or cause breakdown of the winding equipment that is estimated to have not progressed (for example, measurement of dielectric breakdown voltage between winding layers, etc.) ), The insulation characteristics between the winding layers can be diagnosed. Further, since the direct diagnosis between the winding layers is performed on the sample estimated to be deteriorated between the winding layers, the insulation diagnosis between the winding layers is simplified.

  Also, when measuring the discharge start voltage between winding layers, applying a voltage that does not cause discharge between the ground and between the winding layers does not damage the winding equipment. In addition, the insulation between the winding layers can be diagnosed with high accuracy.

[Third Embodiment]
In the winding interlayer insulation diagnosis method for a winding device according to the third embodiment of the present invention, the insulation between winding layers is reduced in the winding interlayer insulation diagnosis method for a winding device according to the first embodiment. The insulation between the winding layers is directly evaluated for the determined winding equipment.

  In the winding interlayer insulation diagnosis method for a winding device according to the third embodiment, the insulation characteristic between winding layers is diagnosed based on the diagnostic parameter of the main insulation as shown in FIG. 1 (STEP 1). Then, the frequency characteristic of the winding impedance of the winding device evaluated that the insulation characteristics between the winding layers are deteriorated by this diagnosis is calculated, and the insulation between the winding layers is directly evaluated (STEP 2).

  Note that the diagnosis procedure of STEP 1 of the winding interlayer insulation diagnosis method for a winding device according to the third embodiment is the same as that of the winding interlayer insulation diagnosis method for the winding device according to the first embodiment. Therefore, in the following description, the diagnosis procedure of STEP 2 that is not explained in the winding interlayer insulation diagnosis method for the winding device according to the first embodiment will be described in detail.

  In the diagnosis procedure of STEP2 of the winding interlayer insulation diagnosis method for a winding device according to the third embodiment of the present invention, AC voltages of different frequencies are applied to the windings of the winding device to be diagnosed, and the alternating current of each frequency is applied. The winding impedance is calculated based on the voltage value and the current that flows when this AC voltage is applied. Then, the insulation between the winding layers is directly diagnosed based on the frequency characteristics (for example, peak shift ratio) of the winding impedance.

[Evaluation of insulation between winding layers]
In the winding interlayer insulation diagnosis method for a winding device according to the third embodiment of the present invention, first, the insulation of the main insulation is evaluated, and using the diagnostic parameter for evaluating the insulation of the main insulation, The insulating property is evaluated (STEP 1). Then, the frequency characteristic of the winding impedance is calculated for the winding device evaluated in STEP1 as having deteriorated insulation between the winding layers, and the insulation between the winding layers is directly diagnosed (STEP2).

  As shown in FIG. 9, it was confirmed that the resonance frequency of the winding impedance changes as the deterioration of the winding progresses in the winding device. Therefore, the ratio (peak shift) of the increase amount of the peak value of the resonance frequency after deterioration to the peak value of the resonance frequency before deterioration was calculated, and the insulation between the winding layers was evaluated based on this peak shift value. .

  As shown in FIG. 10, when the resonance frequency shift (peak shift) is compared with the winding interlayer residual breakdown voltage, it can be confirmed that the winding interlayer residual breakdown voltage decreases as the peak shift increases. Therefore, by setting a threshold value in advance for the deviation (peak shift) of the resonance frequency, it is possible to evaluate the insulation characteristics between the winding layers based on the peak shift. In the example shown in FIG. 10, the peak shift threshold value is 4.0%, but the threshold value can be set as appropriate according to the winding device to be evaluated.

  It is known that the measured value of the winding impedance of a winding device is affected by environmental noise. For example, as a noise source in winding impedance measurement, the influence of electrical equipment driven in a measurement environment, the influence of moisture absorption during rainy weather (the apparent capacitance changes due to moisture absorption during rainy weather), and the like.

  Regarding the noise of electrical equipment, the influence of the noise can be reduced by making the ground wire independent. In addition, with respect to the influence of moisture absorption, winding devices are installed based on diagnostic parameters for diagnosing the insulation of the main insulation (for example, measured values of insulation resistance of the main insulation, measured values of dielectric loss tangent, etc.) By estimating the environment and correcting the measured value of the winding impedance according to the estimated environment, the influence of environmental noise can be reduced.

  In the winding interlayer insulation diagnosis method for a winding device according to the third embodiment of the present invention as described above, the insulation characteristics between the winding layers are evaluated based on the diagnostic parameter for diagnosing the insulation of the main insulation, Winding impedance is measured for the winding equipment that is judged to have poor insulation between the winding layers in the evaluation, and the insulation between the winding layers is directly diagnosed.

  That is, the winding interlayer insulation diagnosis method for a winding device according to the third embodiment of the present invention pays attention to the fact that the winding interlayer capacitance decreases as the deterioration between the winding layers progresses. Based on the above, the insulation between the winding layers is directly diagnosed. Since the voltage applied to the winding in the winding impedance measurement is at most several volts, damage to the winding equipment due to direct diagnosis of the insulation between the winding layers can be reduced.

  In addition, it is a diagnostic parameter for diagnosing the insulation of the main insulation in advance, and by estimating the deterioration state between the winding layers, the insulation between the winding layers is compared with the sample evaluated that the deterioration between the winding layers is progressing. Therefore, the diagnosis of insulation between winding layers can be simplified.

  Also, based on diagnostic parameters for diagnosing the insulation of the main insulation (for example, the insulation resistance of the main insulation and the value of the dielectric loss tangent), the installation environment of the winding equipment (such as the degree of moisture absorption) is judged and By correcting the measured value, the diagnostic accuracy of the insulation between the winding layers is further improved.

  As mentioned above, although the specific embodiment was shown and demonstrated about the winding interlayer insulation diagnostic method of the winding apparatus of this invention, the winding interlayer insulation diagnostic method of the winding apparatus of this invention is restricted to embodiment mentioned above. However, the design can be changed as appropriate without departing from the characteristics of the present invention, and such a modified form also belongs to the technical scope of the present invention.

  For example, the inter-winding layer direct diagnosis procedure (STEP 2) of the second embodiment and the inter-winding layer direct diagnosis procedure (STEP 2) of the third embodiment are performed in combination, thereby further improving the diagnostic accuracy of the insulation between the winding layers. Can be improved.

  In the description of the embodiment, the threshold value of Δtanδ of the main insulation, which is an index for evaluating the deterioration of the winding interlayer insulation, is set to 1.0, and the winding of the rated voltage 3 kV or 6 kV class winding device is set based on this threshold value. It was shown that the interlayer insulation can be evaluated. Similarly, in the description of Embodiment 2, the upper limit of the impulse voltage is set to 3.0 kV as a condition in which no discharge occurs in the main insulation when the impulse voltage is applied, and the rated voltage of 3 kV or 6 kV class winding equipment It was shown that insulation evaluation between winding layers can be performed. The threshold value of Δtanδ and the upper limit of the impulse voltage may be set to optimal values as appropriate according to the size and structure of the device.

  Also, by correcting the measurement results between the winding layers using data such as temperature / humidity data on the usage environment of the winding devices and the load factor of the winding devices, the detection accuracy of the insulation characteristics between the winding layers is improved. In addition, the diagnostic accuracy of insulation between winding layers is further improved.

1 ... Wire 2 ... Coating (wire insulation)
3 ... Interlayer insulation 4 ... Ground-to-earth insulation 5 ... Semiconductive layer 6 ... Iron core (slot)
DESCRIPTION OF SYMBOLS 7 ... Winding interlayer insulation diagnostic system 8 ... Winding equipment 9 ... Winding 10 ... Impulse voltage application apparatus 11 ... Discharge electromagnetic wave detection apparatus 12 ... Electromagnetic wave sensor 13 ... Log amplifier 14 ... High pass filter 15 ... Detection apparatus

Claims (4)

A winding interlayer insulation diagnostic method for diagnosing insulation between winding layers of a winding device comprising a winding and a main insulation provided so as to cover the outer periphery of the wound winding ,
The difference between the dielectric tangent of the main insulation when a predetermined reference voltage is applied to the winding and the dielectric tangent of the main insulation when a test voltage different from the reference voltage is applied to the winding. A threshold is set in advance for the amount of increase in the dielectric tangent of a certain main insulation,
Determine the amount of increase in dielectric loss tangent of the main insulation in the winding device to be diagnosed,
By comparing the obtained increase of the dielectric loss tangent and the threshold value, the insulation between the winding layers of the winding device is diagnosed ,
When the amount of increase in the dielectric tangent of the main insulation is compared with the threshold value and it is diagnosed that the insulation between the winding layers is reduced, the insulation between the winding layers is further reduced. A method of diagnosing a winding interlayer insulation of a winding device, wherein the insulation between the winding layers of the diagnosed winding device is directly diagnosed. Applying an impulse voltage to the winding, and detecting a discharge electromagnetic wave generated between the winding layers when the voltage is applied;
Based on the detected discharge wave, winding interlayer insulation diagnosis method of winding device according to claim 1, wherein the diagnosing insulation of the winding layers directly. Measure the frequency characteristics of the winding impedance of the winding,
Based on the frequency characteristics of the measured winding impedance, the winding interlayer insulation diagnosis method of winding device according to claim 1, wherein the diagnosing insulation of the winding layers directly. The measurement result of the frequency characteristic of the winding impedance is corrected based on an index for evaluating the main insulation of the winding device,
4. The winding interlayer insulation diagnosis method for a winding device according to claim 3 , wherein the insulation between the winding layers is diagnosed based on the measurement result of the corrected frequency characteristic of the winding impedance.

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