JP2021028591A - Diagnostic system and diagnostic method for rotary electric machine - Google Patents

Abstract

To provide a diagnostic system and a diagnostic method for a rotary electric machine capable of detecting abnormality of the rotary electric machine by detecting falling of a magnetic wedge from a slot of a core of a stator or a rotor or loosening of the magnetic wedge from the slot.SOLUTION: A diagnostic system 10 for a rotary electric machine comprises: a current sensor 2 that is installed on a reciprocating cable 5 connected to a coil of a rotary electric machine 1 and measures a reciprocating current flowing in the reciprocating cable 5; and a diagnostic device 20 that inputs the reciprocating current measured by the current sensor 2 and obtains leakage current which is a difference between a current I1 flowing into the coil and a current I2 flowing out of the coil, from the reciprocating current. The diagnostic device 20 obtains a spectrum of a frequency domain of the leakage current from a waveform of the leakage current, and determines that the rotary electric machine 1 is abnormal if the obtained spectrum is different from the spectrum of the frequency domain of the leakage current when the rotary electric machine 1 is normal.SELECTED DRAWING: Figure 1

Description

The present invention relates to a diagnostic system and a diagnostic method for rotating electric machines such as electric motors, generators, and inducers.

When a sudden failure of a rotating electric machine such as an electric motor, a generator, and an induction machine causes an unexpected shutdown of the entire user's system, there is a risk of causing a great loss in social life. For example, if a rotary electric machine is stopped at an unexpected timing in various production factories, all the products being manufactured may be lost and the delivery date to the supplier may be delayed. Also, a sudden generator outage at a power plant can result in significant economic losses. It has been reported that 35% of the causes of failure of rotary electric machines are related to bearings and 35% are related to insulation. Preventing these failures before they occur greatly contributes to the stable operation of rotary electric machines. To do.

In recent years, due to technological innovations in materials and device structures, electric devices including rotary electric machines have come to be designed in a well-balanced manner against trade-offs such as device reliability and ease of manufacture. However, in harsh surrounding environments and operating conditions, there are some cases where electrical equipment breaks down, and it is becoming more important to use inexpensive and highly accurate diagnostic technology together.

As an example of a conventional diagnostic system for a rotary electric machine, Patent Document 1 measures the zero-phase current of a three-phase power supply circuit, and based on the harmonic component extracted from the measured zero-phase current, the power supply circuit of each phase An insulation deterioration diagnostic device that derives an insulation resistance value is described. Further, in Patent Document 2, a zero-phase current is obtained by using a current sensor attached to each of the lead wires of each phase of a rotary electric machine and a current sensor attached to the lead wires of all phases at once. A deterioration diagnosis system for diagnosing deterioration of the bearing and deterioration of the insulation of the stator winding by measuring the leakage current flowing through the insulating material of the stator winding is described.

Japanese Unexamined Patent Publication No. 2013-13040 JP-A-2015-215275

The rotary electric machine includes a stator and a rotor, and the coil is housed in a slot provided in the core of the stator and the rotor. The surface of the coil arranged in the slot is covered with an insulating layer. A magnetic wedge is installed in the opening of the slot to prevent the coil from falling out of the slot.

A large proportion of the causes of rotary electrical accidents is coil breakage due to the magnetic wedge falling out of the slot or loosening relative to the slot. If the magnetic wedge falls out of the slot or loosens from the slot, the magnetic wedge or fragments of the magnetic wedge destroy the insulating layer that covers the coil placed in the slot, causing dielectric breakdown in the rotary electric machine and causing an abnormality. obtain.

Conventional diagnostic systems such as those described in Patent Document 1 and Patent Document 2 cannot detect the magnetic wedge falling out of the slot or loosening in the slot. For this reason, conventionally, the magnetic wedge is mainly visually detected to fall out of the slot or loosen in the slot, and the labor required for detection is large. If there is a detection omission due to oversight, the coil is damaged and the rotary electric machine is damaged. There is a problem that dielectric breakdown may occur. Therefore, there is a demand for a diagnostic system capable of detecting abnormalities in a rotating electric machine, such as a magnetic wedge falling out of a slot or loosening in a slot.

The present invention provides a diagnostic system and a diagnostic method for a rotating electric machine capable of detecting a fall of a magnetic wedge from a slot of a stator or a rotor core or looseness to a slot and detecting an abnormality of the rotating electric machine. The purpose.

The rotary electric machine diagnostic system according to the present invention is installed in a reciprocating cable connected to the coil of the rotary electric machine, and inputs a current sensor that measures the reciprocating current flowing through the reciprocating cable and the reciprocating current measured by the current sensor. A diagnostic device for obtaining a leakage current, which is the difference between the current flowing into the coil and the current flowing out of the coil, from the reciprocating current. The diagnostic apparatus obtains a spectrum of the leakage current frequency region from the leakage current waveform, and if the obtained spectrum is different from the spectrum of the leakage current frequency region when the rotating electric machine is normal, It is determined that the rotary electric machine is abnormal.

The method for diagnosing a rotating electric machine according to the present invention is a measurement step of measuring the reciprocating current flowing through the reciprocating cable with a current sensor installed in a reciprocating cable connected to the coil of the rotating electric machine, and the reciprocating current from the reciprocating current to the coil. The leakage current acquisition step of obtaining the leakage current, which is the difference between the inflowing current and the outflowing current from the coil, and the spectrum of the leakage current frequency region obtained from the leakage current waveform are obtained, and the obtained spectrum is the rotary electric machine. If the spectrum is different from the spectrum of the frequency region of the leakage current in the normal case, the rotary electric machine is provided with a diagnostic step of determining that the abnormality is present.

INDUSTRIAL APPLICABILITY According to the present invention, it is provided a diagnostic system and a diagnostic method for a rotating electric machine capable of detecting a fall of a magnetic wedge from a slot of a stator or a rotor core or looseness to the slot and detecting an abnormality of the rotating electric machine. Can be done.

The figure which shows the structure of the diagnostic system according to Example 1 of this invention. The figure which shows the example of the time change of the earth leakage current. The figure which shows the example of the spectrum of the frequency domain of the leakage current to the ground when the magnetic wedge is normal. The figure which shows the example of the spectrum of the frequency domain of the leakage current to the ground when the magnetic wedge is abnormal. In Example 2 of this invention, the figure which showed the time zone which performs frequency analysis in the example of the time change of the earth leakage current shown in FIG. The figure which shows the structure of the diagnostic system according to Example 3 of this invention. The block diagram which shows the diagnostic system according to Example 1 of this invention, and the rotary electric machine which a diagnostic system diagnoses. The figure which shows a part of the stator of a rotary electric machine. The figure which shows the current sensor installed in the reciprocating cable which consists of a pair of power supply cables consisting of a plurality of cables.

In a rotary electric machine, when the magnetic wedges installed in the slots provided in the stator and the core of the rotor fall off from the slots or become loose with respect to the slots, the magnetic field leaking from the rotary electric machine is distorted. Therefore, by detecting the distortion of the magnetic field leaking from the rotating electric machine, it is possible to detect the falling off or loosening of the magnetic wedge, which has a large proportion of the causes of the insulation accident. The distortion of the magnetic field leaking from the rotating electric machine appears in the harmonic component of the current leaking only from the coil arranged in the slot to the insulating layer covering the surface of the coil (hereinafter referred to as "leakage current to ground").

In the present invention, the reciprocating current flowing through the reciprocating cable connected to each phase of the coil of the rotary electric machine is measured by one current sensor, and the difference between the reciprocating currents is obtained to measure the leakage current to the ground. The reciprocating cable is a pair of cables through which the current flowing into the coil of the rotary electric machine and the current flowing out of the coil flow. The difference in reciprocating current is the difference between the current flowing into the coil and the current flowing out of the coil (difference between the current flowing in one of the reciprocating cables and the current flowing in the other). The leakage current to the ground is obtained as the difference between the reciprocating currents measured by the current sensor.

In the present invention, by performing frequency analysis on the measured ground leakage current, it is possible to efficiently and accurately detect the magnetic wedge falling off from the slot or loosening from the slot.

In the present invention, it is possible to detect abnormalities in the rotating electric machine such as the magnetic wedge falling out of the slot or loosening in the slot, and it is possible to prevent the coil from being damaged and the dielectric breakdown of the rotating electric machine from occurring due to these. As a result, it is possible to provide a new diagnostic method that enables maintenance saving, and it is possible to improve the efficiency of the diagnostic service of the rotary electric machine. Further, as an amount correlating with the insulation characteristics of the rotating electric machine, it is possible to detect a change in the capacitance component of the rotating electric machine in addition to the fluctuation of the magnetic field leaking from the rotating electric machine.

The diagnostic system and diagnostic method for rotary electric machines according to the present invention can diagnose rotary electric machines such as electric motors, generators, and induction machines. In particular, it is effective for rotary electric machines with variable loads used in gas turbines, railways, automobiles, aviation, wind power generators, and the like.

Hereinafter, a diagnostic system and a diagnostic method for a rotary electric machine according to an embodiment of the present invention will be described with reference to the drawings. In the following, an example of diagnosing the stator of the rotary electric machine will be described, but the diagnostic system and the diagnostic method of the rotary electric machine according to the present invention can also diagnose the rotor in the same manner as the stator. In the drawings used in the present specification, the same or corresponding components may be designated by the same reference numerals, and repeated description of these components may be omitted.

The diagnostic system and the diagnostic method of the rotary electric machine according to the first embodiment of the present invention will be described.

FIG. 7 is a block diagram showing a diagnostic system 10 according to a first embodiment of the present invention and a rotary electric machine 1 diagnosed by the diagnostic system 10. The rotary electric machine 1 is connected to the power system 9. The diagnostic system 10 can be connected to the reciprocating cable 5 connected to the rotary electric machine 1. Further, the rotary electric machine 1 is connected to a device 50 that serves as a load.

FIG. 8 is a diagram showing a part of the stator 30 of the rotary electric machine 1. The stator 30 faces the rotor 40 with a gap in between, and includes a stator core 31 and a stator coil 32. The stator core 31 is provided with a slot 33. The stator coil 32 is housed in the slot 33, and its surface is covered with the insulating layer 34. A magnetic wedge 35 is installed in the opening of the slot 33. When the magnetic wedge 35 falls off from the slot 33 or becomes loose with respect to the slot 33, the magnetic wedge 35 and fragments of the magnetic wedge 35 destroy the insulating layer 34 covering the stator coil 32, and the stator coil 32 is damaged. An abnormality of the rotary electric machine 1 such as dielectric breakdown of the rotary electric machine 1 may occur.

FIG. 1 is a diagram showing the configuration of the diagnostic system 10 according to the present embodiment, and shows the entire circuit including the diagnostic system 10, the rotary electric machine 1, and the power system 9. In this embodiment, in the rotary electric machine 1, the three phases of the stator coil 32 are connected by Δ connection. Further, the rotary electric machine 1 is connected to the power system 9 by a power supply cable 3. The power supply cable 3 branches at the terminal block 4 of the terminal box and is connected to the rotary electric machine 1 as a reciprocating cable 5. The reciprocating cable 5 is composed of a pair of power feeding cables 3, and is connected to each phase of the stator coil 32 of the rotary electric machine 1.

The diagnostic system 10 includes a current sensor 2, a measuring device 8, and a diagnostic device 20. The measuring device 8 and the diagnostic device 20 may be composed of one device (for example, a computer) or a plurality of devices.

The current sensor 2 is installed for each phase on the reciprocating cable 5 connected to each phase of the stator coil 32 of the rotary electric machine 1, and is located between the terminal block 4 and the rotary electric machine 1. A total of three current sensors 2 are provided for each phase of the stator coil 32 of the rotary electric machine 1. One current sensor 2 is installed in a pair of power feeding cables 3 constituting the reciprocating cable 5, and measures the reciprocating current flowing through the reciprocating cable 5 (current flowing into the stator coil 32 and current flowing out from the stator coil 32). To do.

The measuring device 8 is connected to the current sensor 2 and includes at least one of a communication device and a storage medium. The communication device transmits the reciprocating current measured by the current sensor 2 to the diagnostic device 20 by wireless communication or wired communication. The storage medium stores the reciprocating current measured by the current sensor 2. The storage medium may be detachable from the measuring device 8. Further, the measuring device 8 may be attached to and detached from the diagnostic device 20. The measuring device 8 can be composed of, for example, a personal computer with a hard disk, a data logger, an oscilloscope provided with a storage device and capable of USB connection, and the like.

The diagnostic device 20 inputs the reciprocating current measured by the current sensor 2 from the measuring device 8. The diagnostic device 20 receives the reciprocating current transmitted from the communication device of the measuring device 8 and inputs the reciprocating current from the measuring device 8 by connecting the storage medium of the measuring device 8 that stores the reciprocating current. .. The diagnostic apparatus 20 obtains a ground leakage current (current leaking only from the stator coil 32 to the insulating layer 34 covering the surface of the stator coil 32) from the input reciprocating current.

In the diagnostic system 10 according to the present embodiment, the current sensor 2 is installed in the reciprocating cable 5 connected to each phase of the stator coil 32 of the rotary electric machine 1, and the reciprocating current flowing through each phase of the stator coil 32 of the rotary electric machine 1 is 1 By measuring with one current sensor 2 and obtaining the difference of the reciprocating current by the diagnostic device 20, the leakage current to the ground in each phase of the stator coil 32 of the rotary electric machine 1 is measured with high accuracy. The leakage current I to the ground is a current that leaks only from the stator coil 32 to the insulating layer 34 that covers the surface of the stator coil 32, and is fixed from the value of the current I1 that flows into the stator coil 32 of the rotary electric machine 1. It can be obtained by subtracting the value of the current I2 flowing out from the child coil 32 to obtain the difference between the reciprocating currents (I = I1-I2).

FIG. 2 is a diagram showing an example of a time change of the ground leakage current, and is a diagram created based on the experimental results of measuring the ground leakage current. The horizontal axis of FIG. 2 indicates time, and the vertical axis indicates the magnitude (amplitude) of leakage current to ground.

As shown in FIG. 2, the time change of the ground leakage current includes a time zone in which the ground leakage current takes a substantially constant value and a time zone in which the ground leakage current increases. That is, the leakage current to the ground fluctuates and increases intermittently. The leakage current to ground takes a substantially constant and stable value in a low output region where the output of the rotary electric machine 1 is small. This constant value is the minimum value of leakage current to ground. The increase in leakage current to the ground occurs when the load of the rotary electric machine 1 fluctuates and the output of the rotary electric machine 1 transitions from the low output region to the high output region and becomes large.

As shown in FIG. 2, the value of the stable leakage current to the ground (amplitude value) that appears in the low output region of the rotary electric machine 1 is referred to as the reference value 12, and the amount of increase in the leakage current to the ground with respect to the reference value 12 is the fluctuation value 11. It is called. The reference value 12 can be the minimum value of the leakage current to the ground.

The diagnostic device 20 performs frequency analysis on the obtained ground leakage current for an arbitrary time zone, and detects that the magnetic wedge 35 has fallen off from the slot 33 of the stator core 31 or loosened in the slot 33. The diagnostic apparatus 20 obtains the spectrum of the ground leakage current in the frequency domain by converting the waveform of the ground leakage current into the spectrum of the frequency domain.

FIG. 3 shows the frequency domain of the leakage current to the ground when the magnetic wedge 35 is normal, that is, when the magnetic wedge 35 has not fallen off from the slot 33 of the stator core 31 or loosened with respect to the slot 33. It is a figure which shows the example of a spectrum, and is the figure which was created based on the experimental result which measured the earth leakage current. The horizontal axis of FIG. 3 indicates the frequency, and the vertical axis indicates the leakage current to the ground (logarithmic value). The rotary electric machine 1 in which the magnetic wedge 35 is normal is, for example, a rotary electric machine after manufacturing and before the start of operation, or a rotary electric machine after repair and before the start of operation.

As shown in FIG. 3, in the rotary electric machine 1 in which the magnetic wedge 35 is normal, the peak 21 of the fundamental wave component is detected as the largest peak in the spectrum of the frequency region of the leakage current to the ground, and the slot harmonic is the next largest peak. A peak 22 due to a wave (a harmonic due to the presence of slot 33) is detected.

FIG. 4 shows the spectrum of the frequency domain of the leakage current to the ground when the magnetic wedge 35 is abnormal, that is, when the magnetic wedge 35 falls off from the slot 33 of the stator core 31 or loosens with respect to the slot 33. It is a figure which shows an example, and is the figure created based on the experimental result which measured the leakage current to the ground. The horizontal axis of FIG. 4 indicates the frequency, and the vertical axis indicates the leakage current to the ground (logarithmic value).

As shown in FIG. 4, in the rotary electric machine 1 in which the magnetic wedge 35 is abnormal, the magnetic wedge 35 is normal in the spectrum of the frequency region of the leakage current to the ground in addition to the peak 21 of the fundamental wave component and the peak 22 due to the slot harmonics. A peak 23 indicating an abnormality, which does not exist in the spectrum of the rotating electric machine 1, is detected. The peak 23 indicating this abnormality is caused by the distortion of the magnetic field leaking from the rotary electric machine 1 due to the magnetic wedge 35 falling off or loosening. In the initial stage of the abnormal state of the magnetic wedge 35, the peak 23 tends to have a smaller amplitude than the peak 22 due to the slot harmonics. However, in the rotary electric machine 1 in which the magnetic wedge 35 is abnormal, the peak 23 in which the magnetic wedge 35 is not present in the rotary electric machine 1 in which the magnetic wedge 35 is normal appears clearly.

Therefore, if the spectrum of the frequency domain of the leakage current to the ground is different from the spectrum of the frequency domain of the leakage current to the ground when the rotary electric machine 1 is normal, that is, when the magnetic wedge 35 is normal, the magnetic wedge 35 is abnormal. Can be judged. Specifically, if a peak that does not exist in the spectrum when the magnetic wedge 35 is normal (however, a peak larger than the noise level) is detected in the spectrum of the frequency region of the leakage current to the ground, the magnetic wedge 35 is abnormal. Can be judged.

The diagnostic apparatus 20 stores the spectrum of the frequency domain of the leakage current to the ground for the normal rotary electric machine 1 (that is, the rotary electric machine 1 in which the magnetic wedge 35 is normal). Then, the diagnostic apparatus 20 compares the obtained spectrum of the frequency region of the leakage current with the ground with the spectrum of the frequency region of the leakage current with respect to the normal rotary electric machine 1, and obtains the spectrum of the frequency region of the leakage current with the ground. When a peak that does not exist in the frequency domain spectrum of the leakage current to ground is detected for the normal rotary electric machine 1, the rotary electric machine 1 is abnormal, that is, the magnetic wedge 35 is dropped from the slot 33 of the stator core 31. It is determined that the slot 33 is loose and abnormal.

The current sensor 2 can also be installed on the reciprocating cable 5 connected to each phase of the stator coil 32 of the rotary electric machine 1 as follows.

The reciprocating cable 5 connected to one phase of the stator coil 32 of the rotary electric machine 1 is composed of a pair of power feeding cables 3. Each of the pair of power supply cables 3 constituting the reciprocating cable 5 can be composed of a plurality of cables. That is, the reciprocating cable 5 may be configured by a pair of power feeding cables 3 composed of a plurality of cables.

FIG. 9 is a diagram showing a current sensor 2 installed in the reciprocating cable 5 in which the reciprocating cable 5 is composed of a pair of power feeding cables 3 composed of a plurality of cables. FIG. 9 shows, as an example, a reciprocating cable 5 in which one of the pair of power supply cables 3 is composed of two cables 3a and 3b and the other is composed of two cables 3c and 3d. .. The power supply cable 3 may be composed of three or more cables.

When the reciprocating cable 5 is composed of a pair of power supply cables 3 composed of a plurality of cables, that is, a power supply cable 3 composed of cables 3a and 3b and a power supply cable 3 composed of cables 3c and 3d, a current sensor 2 can be installed in some of the plurality of cables 3a, 3b, 3c, and 3d constituting the power supply cable 3. FIG. 9 shows, as an example, a configuration in which the current sensor 2 is installed on the cable 3b of one power supply cable 3 and the cable 3c of the other power supply cable 3.

By installing the current sensor 2 on a part of the plurality of cables in this way, even if the reciprocating cable 5 is thick, the current sensor 2 depends on the size of the reciprocating cable 5 and the current sensor 2. 2 can be installed.

In the diagnostic system 10 according to the present embodiment, by performing frequency analysis on the measured ground leakage current, an abnormality of the magnetic wedge 35, that is, the magnetic wedge 35 is dropped from the slot 33 of the stator core 31 or a slot is inserted. Looseness with respect to 33 can be detected efficiently and with high accuracy, an abnormality of the rotary electric machine 1 can be detected, and damage to the stator coil 32 and dielectric breakdown of the rotary electric machine 1 can be prevented.

A diagnostic system and a diagnostic method for a rotary electric machine according to a second embodiment of the present invention will be described. Hereinafter, the differences between the present embodiment and the first embodiment will be mainly described.

The inventors have found that in a rotary electric machine having a load fluctuation, the leakage current to the ground fluctuates as described with reference to FIG. 2 in Example 1. When the ground leakage current fluctuates, the harmonic component of the ground leakage current includes a component caused by mechanical vibration. Therefore, in the spectrum of the frequency range of the ground leakage current, the peak caused by the distortion of the magnetic field leaking from the rotating electric machine. Only difficult to detect.

Therefore, in this embodiment, the diagnostic device 20 removes factors that affect the spectrum of the ground leakage current in the frequency domain other than the abnormality of the magnetic wedge 35, so that the ground leakage current is substantially constant with respect to the obtained ground leakage current. Perform frequency analysis for the time zone that is the value of.

FIG. 5 is a diagram showing a time zone in which frequency analysis is performed in the example of the time change of the leakage current to the ground shown in FIG. The diagnostic device 20 extracts a time zone 13 in which the determined magnitude of the leakage current to the ground does not include the fluctuation value 11 and is within a predetermined range. This range of magnitude of ground leakage current includes the reference value 12, and upper and lower limits can be arbitrarily set so that the ground leakage current can be regarded as approximately the reference value 12. If the magnitude of the ground leakage current is within this range, the diagnostic apparatus 20 determines that the ground leakage current is a substantially constant value (reference value 12).

Then, the diagnostic apparatus 20 performs frequency analysis of the ground leakage current only in the extracted time zone 13, and converts the waveform of the ground leakage current into a spectrum in the frequency domain. That is, the diagnostic apparatus 20 performs frequency analysis of the ground leakage current only in the time zone 13 in which the ground leakage current is approximately the reference value 12 and the fluctuation is small and the SN ratio is high.

In this embodiment, since frequency analysis is performed on the ground leakage current that does not include fluctuations caused by mechanical vibration (for example, vibration due to mechanical deterioration), an abnormality is shown in the frequency domain spectrum of the ground leakage current. The peak 23 (the peak caused by the distortion of the magnetic field leaking from the rotary electric machine 1 due to the falling or loosening of the magnetic wedge 35) can be detected with high accuracy, and the abnormality of the magnetic wedge 35 can be detected with higher accuracy and high sensitivity. ..

In the diagnostic system 10 according to the present embodiment, the abnormality of the magnetic wedge 35 is made more accurate and highly sensitive by performing frequency analysis for the time zone 13 in which the leakage current to the ground does not include the fluctuation value 11 and is a substantially constant value. It can be detected, an abnormality of the rotary electric machine 1 can be detected, and damage to the stator coil 32 and dielectric breakdown of the rotary electric machine 1 can be prevented.

The diagnostic system and the diagnostic method of the rotary electric machine according to the third embodiment of the present invention will be described. Hereinafter, the differences between the present embodiment and the first embodiment will be mainly described.

FIG. 6 is a diagram showing the configuration of the diagnostic system 10 according to the present embodiment, and like FIG. 1, shows the entire circuit including the diagnostic system 10, the rotary electric machine 1, and the power system 9.

In the diagnostic system 10 according to the present embodiment, the measuring device 8 includes at least one of the wireless communication device 7 and the large-capacity storage 6.

When the measuring device 8 includes the wireless communication device 7, the measuring device 8 transmits the measurement data such as the reciprocating current measured by the current sensor 2 to the data center by wireless communication by the wireless communication device 7 and stores it in the data center. .. Further, the measuring device 8 provided with the wireless communication device 7 can also transmit the ground leakage current obtained by the diagnostic device 20 to the data center by wireless communication.

When the measuring device 8 includes the large-capacity storage 6, the measuring device 8 stores the measurement data in the large-capacity storage 6. Further, the measuring device 8 provided with the large-capacity storage 6 can also store the ground leakage current obtained by the diagnostic device 20 in the large-capacity storage 6.

In the diagnostic system 10 according to the present embodiment, the reciprocating current and the leakage current to the ground can be continuously measured while the reciprocating cable 5 is live, so that the amount of data to be accumulated becomes enormous. Therefore, in the case of continuous measurement over a long period of time, it is effective to save the data by transferring the data by the wireless communication device 7 or saving the data in the large-capacity storage 6.

When the data is transferred to the data center by the wireless communication device 7, a problem may occur in the data transfer. Further, if data is continuously accumulated in the large-capacity storage 6 for a long period of time, a problem may occur in data storage. Therefore, in the diagnostic system 10 according to the present embodiment, it is preferable to use the wireless communication device 7 and the large-capacity storage 6 properly or to use both in combination depending on the situation.

A diagnostic system and a diagnostic method for a rotary electric machine according to a fourth embodiment of the present invention will be described. As described with reference to FIG. 7 in Example 1, the rotary electric machine 1 diagnosed by the diagnostic system 10 is connected to the device 50 which is a load. In this embodiment, an example of the rotary electric machine 1 in which the diagnostic system 10 can be diagnosed, which is connected to the device 50 in which the load fluctuation occurs and the load current fluctuates, will be described.

Examples of the rotary electric machine 1 diagnosed by the diagnostic system 10 according to the present embodiment include an automobile motor, a gas turbine generator, a wind power generator, a vehicle rotary electric machine, and an aviation motor. In addition to these, the diagnostic system 10 can diagnose the entire rotary electric machine 1 in which the amount of power generation and the output of the motor fluctuate.

The diagnostic system 10 according to the present embodiment can diagnose the above-mentioned rotary electric machine 1 and the like, can efficiently detect the abnormality of the magnetic wedge 35 with high accuracy, can detect the abnormality of the rotary electric machine 1, and the stator coil 32. It is possible to prevent the damage of the rotary electric machine 1 and the occurrence of the insulation destruction of the rotary electric machine 1.

The diagnostic system and the diagnostic method of the rotary electric machine according to the fifth embodiment of the present invention will be described. The diagnostic system 10 according to the present embodiment can detect the presence or absence of thermal deterioration and moisture absorption deterioration of the insulating layer 34 of the stator coil 32 in the rotary electric machine 1.

In the diagnostic system 10 according to the present embodiment, the capacitance component of the stator coil 32 of the rotary electric machine 1 can be accurately obtained from the leakage current to the ground. In the diagnostic device 20, since the leakage current to the ground is proportional to the capacitance of the stator coil 32, the capacitance of the stator coil 32 can be obtained from the leakage current to the ground. Therefore, the diagnostic apparatus 20 can obtain the change in the capacitance of the stator coil 32 from the change in the leakage current to the ground, and when the capacitance of the stator coil 32 decreases, the insulating layer 34 of the stator coil 32 heats up. It is possible to detect deterioration due to moisture absorption.

Such detection of thermal deterioration and moisture absorption deterioration is particularly effective for the rotary electric machine 1 in which partial discharge deterioration having a rated voltage of 2 kV or less does not occur.

The diagnostic system 10 according to the present embodiment can efficiently detect the abnormality of the magnetic wedge 35 and the thermal deterioration and moisture absorption deterioration of the stator coil 32 with high accuracy, especially for the rotary electric machine 1 having a rated voltage of 2 kV or less. An abnormality of the rotary electric machine 1 can be detected, and damage to the stator coil 32 and insulation destruction of the rotary electric machine 1 can be prevented.

The present invention is not limited to the above embodiment, and various modifications are possible. For example, the above-described embodiment has been described in detail in order to explain the present invention in an easy-to-understand manner, and the present invention is not necessarily limited to the embodiment including all the described configurations. In addition, it is possible to replace a part of the configuration of one embodiment with the configuration of another embodiment. It is also possible to add the configuration of another embodiment to the configuration of one embodiment. In addition, it is possible to delete a part of the configurations of each embodiment and add / replace other configurations.

1 ... Rotating electric machine, 2 ... Current sensor, 3 ... Power supply cable, 3a, 3b, 3c, 3d ... Cables that make up the power supply cable, 4 ... Terminal block, 5 ... Reciprocating cable, 6 ... Large capacity storage, 7 ... Wireless communication Equipment, 8 ... Measuring device, 9 ... Power system, 10 ... Diagnostic system, 11 ... Fluctuation value, 12 ... Reference value, 13 ... Time zone for frequency analysis of leakage current to ground in Example 2, 20 ... Diagnostic device, 21 ... peak of fundamental wave component, 22 ... peak due to slot harmonics, 23 ... peak indicating abnormality, 30 ... stator, 31 ... stator core, 32 ... stator coil, 33 ... slot, 34 ... insulating layer, 35 ... Magnetic wedge, 40 ... rotor, 50 ... load device.

Claims (9)

A current sensor installed on a reciprocating cable connected to the coil of a rotary electric machine and measuring the reciprocating current flowing through the reciprocating cable.
A diagnostic device that inputs the reciprocating current measured by the current sensor and obtains a leakage current that is the difference between the current flowing into the coil and the current flowing out of the coil from the reciprocating current.
With
The diagnostic apparatus obtains a spectrum of the leakage current frequency region from the leakage current waveform, and if the obtained spectrum is different from the spectrum of the leakage current frequency region when the rotating electric machine is normal, Judging that the rotary electric machine is abnormal,
A diagnostic system for rotating electric machines, which is characterized by this. When the diagnostic apparatus detects in the obtained spectrum a peak that does not exist in the spectrum in the frequency region of the leakage current when the rotary electric machine is normal, it determines that the rotary electric machine is abnormal.
The diagnostic system for a rotary electric machine according to claim 1. The diagnostic device obtains the spectrum of the frequency region of the leakage current from the waveform of the leakage current only in a time zone in which the magnitude of the leakage current is within a predetermined range.
The diagnostic system for a rotary electric machine according to claim 1. The reciprocating cable is composed of a pair of power supply cables, and the power supply cable is composed of a plurality of cables.
The current sensor is installed in a part of the plurality of cables constituting the power supply cable.
The diagnostic system for a rotary electric machine according to claim 1. The current sensor is installed in the reciprocating cable connected to the coil of the rotary electric machine whose load fluctuates.
The diagnostic system for a rotary electric machine according to claim 1. The current sensor is installed in the reciprocating cable connected to the coil of the rotating electric machine having a rated voltage of 2 kV or less.
The diagnostic system for a rotary electric machine according to claim 1. A measurement process that measures the reciprocating current flowing through the reciprocating cable with a current sensor installed on the reciprocating cable connected to the coil of the rotary electric machine.
A leakage current acquisition step of obtaining a leakage current, which is the difference between the current flowing into the coil and the current flowing out of the coil, from the reciprocating current.
The spectrum of the frequency region of the leakage current is obtained from the waveform of the leakage current, and if the obtained spectrum is different from the spectrum of the frequency region of the leakage current when the rotating electric machine is normal, the rotating electric machine is abnormal. And the diagnostic process to determine that
A method for diagnosing a rotating electric machine, which comprises. In the diagnostic step, if a peak that does not exist in the spectrum in the frequency region of the leakage current when the rotary electric machine is normal is detected in the obtained spectrum, it is determined that the rotary electric machine is abnormal.
The diagnostic method for a rotary electric machine according to claim 7. In the diagnostic step, the spectrum of the frequency region of the leakage current is obtained from the waveform of the leakage current only in the time zone in which the magnitude of the leakage current is within a predetermined range.
The diagnostic method for a rotary electric machine according to claim 7.

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