JP7560367B2 - Method and device for diagnosing insulation deterioration in a rotating electrical machine - Google Patents

Description

The present invention relates to a method and device for diagnosing insulation deterioration in rotating electrical machines.

In rotating electric machines, if corona discharge occurs through the insulator, the insulator may deteriorate. Conventionally, insulation deterioration diagnosis methods for diagnosing the deterioration of the insulator are known. For example, there is an insulation deterioration diagnosis method that corrects the ozone concentration inside the rotating electric machine using the temperature and humidity inside the rotating electric machine, and diagnoses the deterioration of the insulation based on the corrected ozone concentration.

JP 2020-061797 A

It would be beneficial for this type of insulation deterioration diagnosis device to improve the accuracy of detecting corona discharges.

Therefore, one of the objectives of the present invention is to improve the accuracy of diagnosing insulation deterioration in rotating electrical machines.

A method for diagnosing insulation deterioration of a rotating electric machine according to an embodiment of the present invention includes an acquisition step of acquiring an ozone concentration, temperature, humidity, and wind speed of the airflow inside a housing of a rotating electric machine including a housing, a stator housed in the housing, a rotor housed in the housing and rotating relative to the stator, an insulator housed in the housing, and a fan that generates an airflow inside the housing, and a diagnosis step of diagnosing deterioration of the insulator based on the ozone concentration, temperature, humidity, and wind speed, wherein in the diagnosis step, an ozone generation rate, which is the number of ozone molecules generated per unit time in a specified volume, is calculated based on the ozone concentration, temperature, humidity, and half-life of ozone at the ozone concentration, temperature, humidity, and wind speed, and a discharge power of corona discharge generated inside the housing is calculated based on the ozone generation rate .

The method for diagnosing insulation deterioration of a rotating electric machine according to an embodiment of the present invention can improve the accuracy of diagnosing insulation deterioration of a rotating electric machine.

FIG. 1 is a diagram illustrating an example of a configuration of a rotating electrical machine system according to an embodiment. FIG. 2 is a cross-sectional view illustrating an example of a stator winding of a stator in a rotating electric machine according to the embodiment. FIG. 3 is a block diagram illustrating an example of the configuration of an insulation degradation diagnosis device according to an embodiment. FIG. 4 is a flowchart illustrating an example of an insulation degradation diagnosis process executed by a calculation unit of the insulation degradation diagnosis device according to the embodiment. FIG. 5 is a diagram showing the relationship between the discharge power of corona discharge and the deterioration state of the insulating coating in the rotating electric machine of the embodiment.

The following describes exemplary embodiments of the present invention. The configurations (technical features) of the embodiments described below, as well as the actions and results (effects) brought about by the configurations, are all merely examples.

<Rotating Electric Machine System 1>
Fig. 1 is a diagram illustrating an example of a configuration of a rotating electric machine system 1 according to an embodiment. As illustrated in Fig. 1, the rotating electric machine system 1 includes a totally enclosed fan-cooled rotating electric machine 100 and an insulation degradation diagnosis device 200. The rotating electric machine 100 is, for example, a three-phase induction motor. However, the rotating electric machine 100 is not limited to the above. The insulation degradation diagnosis device 200 diagnoses insulation degradation of the rotating electric machine 100.

<Configuration of rotating electric machine 100>
As shown in Fig. 1, the rotating electric machine 100 includes a rotating electric machine main body 2 that rotates, a cooler 3, and a housing 5. The housing 5 is provided between the rotating electric machine main body 2 and the cooler 3. Inside the rotating electric machine 100, a closed space 4 filled with a cooling gas (hereinafter simply referred to as gas) is provided between the rotating electric machine main body 2 and the cooler 3. The gas is, for example, air. The gas inside the closed space 4 that is heated by heat generated by a stator 13, which is an example of a heating element, is heat-exchanged with outside air by the cooler 3, thereby cooling the rotating electric machine main body 2.

The rotating electric machine body 2 has a frame 11a, a rotor 12, and a stator 13.

The frame 11a is formed in a box shape with an open top. The frame 11a houses a part of the rotor 12 and the stator 13. A partition plate 11c is installed at the top end of the frame 11a, and the top end of the frame 11a is closed by the partition plate 11c. The frame 11a and the partition plate 11c form the first housing 5a. The frame 11a is also referred to as a housing member.

The rotor 12 has a rotor shaft 14 and a rotor core 15. The rotor core 15 is fixed to the portion of the rotor shaft 14 between both axial ends.

The rotor shaft 14 is rotatably supported by the frame 11a via two bearings 16. The two bearings 16 are located on both sides of the rotor core 15 in the axial direction of the rotor shaft 14. The bearings 16 are, for example, sliding bearings or rolling bearings.

Both axial ends of the rotor shaft 14 protrude from the frame 11a to the outside of the frame 11a. A coupling portion 14a is provided at one axial end of the rotor shaft 14. The coupling portion 14a is coupled to a rotating machine (not shown). An outer fan 17 is fixed to the other axial end of the rotor shaft 14. The outer fan 17 rotates integrally with the rotor shaft 14. An inner fan 18 is fixed between each of the two bearings 16 and the rotor core 15 on the rotor shaft 14. The inner fan 18 rotates integrally with the rotor shaft 14. By rotating, the inner fan 18 circulates gas between the stator 13 and the rotor 12 and the cooler 3 (more specifically, the heat exchanger 31 described later). That is, the inner fan 18 generates an air flow within the housing 5. The inner fan 18 is an example of a fan.

The stator 13 has a stator core 19 and a stator winding 20. The stator core 19 is located outside the rotor core 15 in the radial direction of the rotor shaft 14, and is formed in a cylindrical shape surrounding the rotor core 15. The stator winding 20 passes through a plurality of slots 23 (see FIG. 2) formed in the inner peripheral surface 19a of the stator core 19 so as to extend in the axial direction of the rotor shaft 14, and is fixed to the stator core 19 by wedges 22 (see FIG. 2).

The cooler 3 has a heat exchanger 31, an external fan cover 32, and an outlet guide 33.

The heat exchanger 31 has a plurality of cooling pipes 41, an inlet end plate 42, an outlet end plate 43, and a cooler cover 45. The cooling pipes 41 are arranged in parallel with each other. The inlet end plate 42 and the outlet end plate 43 support both ends of the cooling pipes 41 in the axial direction. The cooler cover 45 is provided across the inlet end plate 42 and the outlet end plate 43, and houses the cooling pipes 41.

The inlet end plate 42, the outlet end plate 43, and the cooler cover 45 form the frame 11b. The frame 11b is fixed to the upper end of the rotating electric machine body 2. A partition plate 11c is installed at the lower end of the frame 11b, and the lower end of the frame 11b is closed by the partition plate 11c. The frame 11b and the partition plate 11c form the second housing 5b. That is, the housing 5 is composed of the second housing 5b that houses the cooler 3 and the first housing 5a that houses the rotating electric machine body 2. The first housing 5a and the second housing 5b are separated by the partition plate 5c. The frame 11b is also called a housing member.

The cooling pipe 41, the inlet end plate 42, the outlet end plate 43, the cooler cover 45, and the frame 11a are connected to each other to form the closed space 4. The space 4a in the frame 11a and the space 4b in the cooler cover 45 in the closed space 4 are both connected to each other by the inlet 10a and two outlets 10b formed in the partition plate 11c. The inlet 10a is formed in the part of the frame 11a above the stator 13. The two outlets 10b are formed in the part of the frame 11a diagonally above the inner fan 18. In other words, the inlet 10a is located between the two outlets 10b.

Two guide plates 44 are provided inside the cooler cover 45. The two guide plates 44 are arranged at a distance from each other in the axial direction of the cooling pipe 41 between the inlet end plate 42 and the outlet end plate 43. The two guide plates 44 extend upward from the bottom of the space 4b inside the cooler cover 45, and divide the space 4b inside the cooler cover 45, excluding the upper communication space 4c, in the axial direction of the cooling pipe 41.

The external fan cover 32 is fixed to the inlet end plate 42 and houses the external fan 17. The external fan cover 32 is provided with an inlet 37, and as the external fan 17 rotates, external air flows into the external fan cover 32 from the inlet 37. The external fan cover 32 is connected to the inlet end plate 42 so that the external air flowing into the external fan cover 32 by the external fan 17 flows inside the multiple cooling pipes 41. A guide member 46 is provided inside the external fan cover 32 to guide the external air that flows into the external fan cover 32 from the inlet 37 so that it passes through the external fan 17 and flows into the multiple cooling pipes 41.

The outlet guide 33 is fixed to the outlet end plate 43. The outlet guide 33 guides the outside air flowing out of the multiple cooling tubes 41 so that it flows in a predetermined direction.

The rotating electric machine 100 also includes an ozone concentration meter 211, a thermometer 212, a hygrometer 213, and an anemometer 214. The ozone concentration meter 211, the thermometer 212, the hygrometer 213, and the anemometer 214 are housed in the first housing 5a of the housings 5. The ozone concentration meter 211, the thermometer 212, and the hygrometer 213 are installed, for example, near the end of the stator winding 20 protruding from the stator core 19. The ozone concentration meter 211 measures, for example, the ozone concentration in the first housing 5a. The thermometer 212 measures the temperature in the first housing 5a. The hygrometer 213 measures the humidity in the first housing 5a. The anemometer 214 measures the wind speed (gas speed) of the airflow in the first housing 5a. The anemometer 214 is disposed, for example, downstream of the internal fan 18. Here, the wind speed in the first housing 5a is approximately constant during constant speed rotation of the rotating electric machine 100. The installation positions of the ozone concentration meter 211, the thermometer 212, the hygrometer 213, and the anemometer 214 are not limited to the positions shown in FIG. 1. In addition, the ozone concentration meter 211, the thermometer 212, the hygrometer 213, and the anemometer 214 are, for example, housed (installed) in the first housing 5a only when the measurement target is being measured. That is, the ozone concentration meter 211, the thermometer 212, the hygrometer 213, and the anemometer 214 do not have to be housed (installed) in the first housing 5a at all times. The ozone concentration meter 211, the thermometer 212, the hygrometer 213, and the anemometer 214 may be housed (installed) in the first housing 5a at all times.

<Gas Flow in Rotating Electric Machine 100>
Next, the flow of gas inside the rotating electrical machine 100 will be described.

First, the cooling gas (gas) in the closed space 4 will be described. The gas in the space 4a in the frame 11a in the closed space 4 is compressed by two internal fans 18 that rotate together with the rotor shaft 14, flows along the rotor 12 and the stator 13 to cool the rotor 12 and the stator 13, and then flows out radially outward of the stator core 19. At this time, the gas passes through the ventilation passages provided in the rotor 12 and the stator 13. The gas that flows out radially outward of the stator core 19 forms an airflow F1 and flows into the space 4b in the cooler 3 via the inlet 10a. In the process of passing outside the cooling pipe 41, the gas that flows into the space 4b of the cooler 3 exchanges heat with the outside air flowing in the cooling pipe 41 and is cooled, while rising between the two guide plates 44 and flowing out into the upper communication space 4c.

The gas in the upper communication space 4c branches off in opposite directions along the axial direction of the cooling pipe 41, and flows down between the inlet end plate 42 and the guide plate 44, and between the outlet end plate 43 and the guide plate 44, while being cooled by heat exchange with the outside air in the cooling pipe 41. The gas then forms air flows F2 and F3, returning to the space 4a in the frame 11a via the outlet 10b, and again flowing into the inner fan 18.

Next, the flow of outside air will be explained. Outside air flows into the outside fan cover 32 from the suction port 37 by the outside fan 17 that rotates together with the rotor shaft 14, passes through the inside of the outside fan cover 32, and reaches the inlet end plate 42. The outside air that reaches the inlet end plate 42 flows into each cooling pipe 41 that opens at the inlet end plate 42, receives heat from the gas outside the cooling pipe 41 in the cooling pipe 41, passes through the cooling pipe 41 while increasing in temperature, and then flows out of the cooler 3 from the opening on the outlet end plate 43 side. In this way, heat is exchanged between the outside air inside the cooling pipe 41 and the gas outside the cooling pipe 41, thereby cooling the rotor 12 and the stator 13.

<Winding Structure of Stator 13>
Next, the winding structure of the stator 13 will be described with reference to Fig. 2. Fig. 2 is a cross-sectional view showing an example of the stator winding 20 of the stator 13 in the rotating electric machine 100 of the embodiment.

As shown in FIG. 2, the stator core 19 that constitutes the stator 13 has multiple slots 23 formed along the inner peripheral surface 19a. Inside the slots 23, the stator winding 20 is wound in two layers, one above the other. The surface of the stator winding 20 is covered with an insulating coating 21. The insulating coating 21 is an example of an insulator.

A wedge 22 is fitted above the stator winding 20. The wedge 22 is made of an insulating material such as a resin material. The wedge 22 prevents the stator winding 20 from falling out of the slot 23 due to vibrations that occur when the rotating electric machine 100 rotates.

<Configuration of insulation deterioration diagnosis device 200>
Next, the insulation degradation diagnosis device 200 will be described with reference to Fig. 3. Fig. 3 is a block diagram showing an example of the configuration of the insulation degradation diagnosis device 200 according to the embodiment.

As shown in FIG. 3, the insulation deterioration diagnosis device 200 includes a calculation unit 201, a storage device 202, a communication unit 203, and an input/output unit 204. The calculation unit 201, the storage device 202, the communication unit 203, and the input/output unit 204 are connected to each other so that information and signals can be exchanged.

The storage device 202 stores various types of information. The storage device 202 is a well-known storage medium.

The communication unit 203 is a communication interface for communicating with other devices. For example, the communication unit 203 communicates by wire with the ozone concentration meter 211, the thermometer 212, the hygrometer 213, and the anemometer 214. The communication unit 203 may also communicate wirelessly with the ozone concentration meter 211, the thermometer 212, the hygrometer 213, and the anemometer 214.

The input/output unit 204 includes an input unit that receives operation instructions from an operator such as a worker, and a display unit that displays images. The input unit is, for example, a keyboard, a mouse, etc. The display unit is, for example, a liquid crystal display device, an organic EL (Electro Luminescence) display, etc. The input/output unit 204 may be a touch panel display that has an input unit and a display unit integrated together.

The calculation unit 201 has a CPU (Central Processing Unit), a ROM (Read Only Memory), and a RAM (Random Access Memory). In other words, the calculation unit 201 is a computer. The CPU reads out and executes programs stored in the ROM, etc. The CPU is also configured to be capable of parallel processing of various calculation processes. The RAM temporarily stores various data used when the CPU executes programs to perform various calculation processes. The calculation unit 201 is also referred to as a calculation unit or an information processing unit.

The calculation unit 201 has, as its functional components, an acquisition unit 201a and a diagnosis unit 201b. These functional components are realized as a result of the CPU executing a program stored in a ROM or the like. Note that some or all of the above functional components may be realized by dedicated hardware (circuitry).

The acquisition unit 201a acquires various information and signals. For example, the acquisition unit 201a acquires the ozone concentration, temperature, humidity, and wind speed within the first housing 5a from the ozone concentration meter 211, the thermometer 212, the hygrometer 213, and the anemometer 214.

The diagnosis unit 201b diagnoses the deterioration of the insulating coating 21 based on the information (ozone concentration, temperature, humidity, wind speed) acquired by the acquisition unit 201a.

<Deterioration diagnosis method>
A deterioration diagnosis method for diagnosing deterioration of the insulating coating 21 will be described below.

この式（１）の解は、初期条件であるＮ（０）=Ｎ_０から、

となる。
一方、オゾン分子が、単位時間、単位体積あたりにｑ個生成され、オゾン分解定数λで分解されると考えると、オゾンの発生と分解は、次の微分方程式（式（３））で与えられる。なお、筐体５からのオゾンの漏れを考慮する場合は（λ）に替えて（λ+α）とすればよい。αは、所定の定数である。

この式（３）の解は、次式（４）で示される。

十分に時間が経ったとき（平衡時）の分子数は、ｑ／λとなり、平衡状態に達した後で測定したオゾン濃度［О_３］と所定の容積Ｖとから、所定の容積Ｖでのオゾン分子数はＶ[О_３］となる。ここで、所定の容積Ｖ全体での単位時間あたりのオゾン発生個数をＱとし、発生したオゾンは速やかに所定の容積内に拡散するものとする。所定の容積Ｖ全体での単位時間あたりのオゾン発生個数＝オゾン発生速度とする。よって、以降では、オゾン発生速度にもＱが用いられる。Ｑ＝ｑＶおよびｑ／λ＝［О_３］より、オゾン発生速度（すなわち、所定の容積Ｖ全体での単位時間あたりのオゾン発生個数）Ｑは、次式（５）により求めることができる。

(Ozone generation and decomposition)
First, the generation and decomposition of ozone will be explained. In the natural decomposition of ozone, the change in the number of ozone molecules per unit volume (ozone concentration) over time can be described as a differential equation. First, if the decomposition constant of ozone (hereinafter also referred to as the ozone decomposition constant) is λ, the time is t, and the number of ozone molecules at t=0 is _N0 , then the number of ozone molecules N(t) at time t follows the following differential equation (Equation (1)).

The solution of this equation (1) is given by the initial condition N(0)=N ₀ as follows:

It becomes.
On the other hand, if it is considered that q ozone molecules are generated per unit time and unit volume and are decomposed with an ozone decomposition constant λ, the generation and decomposition of ozone is given by the following differential equation (Equation (3)). Note that when considering the leakage of ozone from the housing 5, (λ) can be replaced with (λ+α), where α is a predetermined constant.

The solution of this equation (3) is given by the following equation (4).

The number of molecules after a sufficient amount of time has passed (at equilibrium) is q/λ, and the number of ozone molecules in the specified volume V is V[ _O3 ] from the ozone concentration [ _O3 ] measured after reaching equilibrium and the specified volume V. Here, the number of ozone molecules generated per unit time in the entire specified volume V is Q, and the generated ozone is assumed to diffuse quickly within the specified volume. The number of ozone molecules generated per unit time in the entire specified volume V = the ozone generation rate. Therefore, hereafter, Q will also be used for the ozone generation rate. From Q = qV and q/λ = [ _O3 ], the ozone generation rate Q (i.e., the number of ozone molecules generated per unit time in the entire specified volume V) can be calculated by the following formula (5).

が得られる。すなわち、

である。
したがって、オゾンの半減期（ｔ_１／２）の測定結果（算出結果）からλを求めることができる。上記文献では様々な環境条件の下でオゾンの半減期（ｔ_１／２）が測定されているので、それを用いてλに対する温度、湿度および風量の影響を検討することができる。すなわち、回転電機１００の筐体５内の温度、湿度および風量が分かれば、λが求まる。ここで、本実施形態では、風量として内扇１８の風量が用いられる。内扇１８の風量は、風速および内扇１８の羽根の径から求めることができる。 (Estimation of ozone decomposition constant)
The ozone decomposition constant is calculated using the following formula (11) shown in the literature (Half-life time of ozone as a function of air movement and conditions in a sealed container).
Y=2274.4+0.483×x1-8.49×x2-51.64×x3-12.01×x4 (Formula 11)
Here, in the above formula (11), Y = ozone half-life, x1 = initial ozone concentration, x2 = air volume, x3 = temperature, and x4 = humidity.
In the above document, the half-life of natural decomposition of ozone under various environmental conditions (temperature, humidity, air volume) is calculated. Since the natural decomposition of ozone follows the above-mentioned formula (2), the definition of the half-life in formula (11) is as follows:

That is,

It is.
Therefore, λ can be obtained from the measurement (calculation) results of the half-life (t _1/2 ) of ozone. In the above-mentioned document, the half-life (t _1/2 ) of ozone is measured under various environmental conditions, and the influence of temperature, humidity, and air volume on λ can be considered using the measurements. That is, λ can be obtained if the temperature, humidity, and air volume inside the housing 5 of the rotating electric machine 100 are known. Here, in this embodiment, the air volume of the internal fan 18 is used as the air volume. The air volume of the internal fan 18 can be obtained from the wind speed and the diameter of the blades of the internal fan 18.

ｋ_１とｋ_４とは、放電状態すなわち電子のエネルギ分布のみで決まる反応速度定数であり、ｋ₂とｋ_３とは、気体の温度で決まる反応速度定数である。 (Ozone generation due to corona discharge)
The reaction of ozone generation by discharge in the atmosphere is considered to be as follows: where, "k"
represents the reaction rate constant.

_k1 and _k4 are reaction rate constants determined only by the discharge state, i.e., the energy distribution of electrons, and _k2 and _k3 are reaction rate constants determined by the gas temperature.

である。 moreover,

It is.

ここで、上記式（３７）におけるｘは全圧に対する酸素の分圧比であり、ｃ_１は所定の定数である。すなわち、

である。
したがって、

である。
すなわち、オゾン濃度が低濃度の場合、単位時間当たりのオゾン収量（＝オゾン発生量）は放電電力Ｗに比例する。上記のオゾン発生速度と合わせて考えると、

となり、オゾン濃度と放電電力Ｗとの関係はオゾン分解定数に依存する。上記式（４０）のｃ_２は、所定の定数である。 Equation (31) is the same as equation (22) in the case where the third body is _N2 (nitrogen), and the ratio of _k2 to _k'2 is 1:0.89, and there is no significant difference in the effects of oxygen and nitrogen as the third body. Equation (32) is the excitation of _N2 to _N2 ^* by electrons, equation (33) is the dissociation of _O2 (oxygen) by _N2 ^* , equations (34) and (35) are the deexcitation of _N2 ^* , and equation (36) is the decomposition reaction of _O3 by _N2 ^* . Here, _kN1 is determined by E/n, and _kN2 , kN3, _{k'N3 ,} and _kN4 are mainly determined by the gas temperature. Here, E/n is the reduced electric field, E is the electric field, and n is the air density. In the initial stage of ozone generation, equations (31) to (35) can be added to equations (21) and (22). Therefore, the maximum ozone yield ( _Yo3 /W) _max is given by the following equation (37), where _Yo3 is the amount of ozone generated and W is the discharge power.

Here, in the above formula (37), x is the partial pressure ratio of oxygen to the total pressure, and _c1 is a predetermined constant. That is,

It is.
therefore,

It is.
That is, when the ozone concentration is low, the ozone yield (= amount of ozone generated) per unit time is proportional to the discharge power W. Considering this together with the above ozone generation rate,

The relationship between the ozone concentration and the discharge power W depends on the ozone decomposition constant. _c2 in the above formula (40) is a predetermined constant.

From the above, the discharge power W of the corona discharge can be calculated from the ozone concentration, temperature, humidity, and wind speed inside the housing 5. Here, the relationship between the discharge power W and the discharge area of the insulator (insulating coating 21) is obtained, for example, through an experiment, and a relational equation showing this relationship is stored in the memory device 202. This allows the relationship between the calculated discharge power W and the deterioration state of the insulator to be calculated. Also, as can be seen from the above, the reaction rate coefficient of the gas (oxygen, nitrogen) is used in calculating the discharge power W of the corona discharge.

The ozone concentration is measured while the rotating electric machine 100 is in operation. Because ozone is easily decomposed by heat, it is desirable to measure the ozone concentration at a location in the rotating electric machine 100 where the temperature is as low as possible. The ozone concentration during operation may be estimated while the machine is stopped. For example, the ozone concentration during operation may be estimated from the measured ozone concentration, taking into account the attenuation characteristics of temperature and humidity, using the temperature and humidity inside the housing 5 when the ozone concentration is measured, and information on the temperature, humidity, flow rate, and time from the stop of operation to the measurement of ozone.

<Insulation Deterioration Diagnosis Processing>
Next, the insulation degradation diagnosis process executed by the calculation unit 201 of the insulation degradation diagnosis device 200 will be described with reference to Fig. 4 and Fig. 5. The insulation degradation diagnosis process performs degradation diagnosis using the insulation degradation method described above.

Figure 4 is a flowchart showing an example of the insulation deterioration diagnosis process executed by the calculation unit 201 of the insulation deterioration diagnosis device 200 of the embodiment. Figure 5 is a diagram showing the relationship between the discharge power of corona discharge and the deterioration state of the insulation coating 21 in the rotating electric machine 100 of the embodiment.

First, as shown in FIG. 4, the acquisition unit 201a acquires the ozone concentration, temperature, humidity, and wind speed within the first housing 5a from the ozone concentration meter 211, the thermometer 212, the hygrometer 213, and the anemometer 214 (S101: acquisition step). Here, the acquired wind speed of the airflow within the first housing 5a is the wind speed at the location where the anemometer 214 is installed.

Next, the diagnosis unit 201b calculates the ozone decomposition constant λ based on the temperature, humidity, and wind speed inside the first housing 5a acquired by the acquisition unit 201a (S102). The ozone decomposition constant λ is found from equation (14). Next, the diagnosis unit 201b calculates the ozone generation rate Q based on the ozone concentration and the ozone decomposition constant λ (S104). The ozone generation rate Q is found from equation (5). Next, the diagnosis unit 201b calculates the discharge power of the corona discharge based on the ozone generation rate Q (S104). The discharge power W can be found using equations (40) and (5).

Next, the diagnostic unit 201b judges the deterioration state of the insulator, specifically the deterioration state of the insulating coating 21, based on the calculated discharge power W (S105). At this time, the diagnostic unit 201b judges the deterioration state of the insulating coating 21 from the relationship between the discharge power W of the corona discharge and the deterioration state of the insulating coating 21 shown in FIG. 5. That is, the diagnostic unit 201b judges that the greater the discharge power of the corona discharge, the more severe the deterioration of the insulating coating 21, i.e., the greater the degree of deterioration. The diagnostic unit 201b outputs the judgment result, i.e., the diagnosis result, from the input/output unit 204 (S106). Furthermore, if the deterioration of the insulating coating 21 exceeds a specified state, the diagnostic unit 201b outputs a warning from the input/output unit 204. S102 to S106 constitute the diagnostic steps.

Here, as described above, in this embodiment, as an example, the wind speed in the first housing 5a is approximately constant during constant speed rotation operation of the rotating electric machine 100. Therefore, in the insulation deterioration diagnosis process during constant speed rotation operation of the rotating electric machine 100, the measurement of the wind speed in the first housing 5a only needs to be performed at least once. At this time, for example, the wind speed in the first housing 5a is measured once by the anemometer 214, and the measurement result (wind speed) is stored in the storage device 202. As a result, in S101, the acquisition unit 201a can acquire (read) the wind speed stored in the storage device 202. In this case, in the first insulation deterioration diagnosis process, the acquisition unit 201a may acquire the wind speed from the anemometer 214 and store it in the storage device 202 in S101, and in the second or subsequent insulation deterioration diagnosis processes, the wind speed may be acquired from the storage device 202 in S101. As another example, the acquisition unit 201a may store the wind speed acquired from the anemometer 214 in the storage device 202 before the insulation degradation diagnosis process, and acquire the wind speed from the storage device 202 in each insulation degradation diagnosis process, including the first one. The acquisition unit 201a may acquire the wind speed from the anemometer 214 in each insulation degradation diagnosis process, including the first one.

Effects of the embodiment
As described above, the insulation deterioration diagnosis method of the present embodiment is an insulation deterioration diagnosis method for a rotating electric machine 100 including a housing 5, a stator 13 housed in the housing 5, a rotor 12 housed in the housing 5 and rotating relative to the stator 13, an insulating coating 21 (insulator) housed in the housing 5, and an internal fan 18 (fan) that generates an airflow within the housing 5. The insulation deterioration diagnosis method includes an acquisition step and a diagnosis step. In the acquisition step, the acquisition unit 201a acquires the ozone concentration, temperature, humidity, and airflow speed within the housing 5 of the rotating electric machine 100. In the diagnosis step, the diagnosis unit 201b diagnoses the deterioration of the insulating coating 21 based on the ozone concentration, temperature, humidity, and airflow speed. Therefore, in order to diagnose deterioration of the insulating coating 21, in addition to the ozone concentration, temperature, and humidity, the air flow speed inside the housing 5 is also used, so that the accuracy of the diagnosis can be improved compared to when the deterioration of the insulating coating 21 is diagnosed using only the ozone concentration, temperature, and humidity.

In addition, in this embodiment, in the diagnosis step, the diagnosis unit 201b calculates the discharge power W of the corona discharge generated inside the housing 5 based on the ozone concentration, temperature, humidity, and wind speed, and diagnoses the deterioration of the insulating coating 21 insulator based on the discharge power W. This further improves the accuracy of the diagnosis.

In the above embodiment, the insulating coating 21 of the stator core 19 is shown as an example of an insulator, but this is not limiting. For example, if the rotor 12 is provided with a rotor winding as a winding, the insulating coating of the rotor winding may be an example of an insulator.

Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the gist of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are included in the scope of the invention and its equivalents described in the claims.

5...Housing, 12...Rotor, 13...Stator, 18...Inner fan, 21...Insulation coating (insulator), 100...Rotating electric machine, 200...Insulation deterioration diagnosis device, 201a...Acquisition unit, 201b...Diagnostic unit.

Claims (2)

an acquisition step of acquiring an ozone concentration, a temperature, a humidity, and a wind speed of the airflow in a housing of a rotating electric machine including a housing, a stator housed in the housing, a rotor housed in the housing and rotating relative to the stator, an insulator housed in the housing, and a fan that generates an airflow in the housing;
a diagnosis step of diagnosing deterioration of the insulator based on the ozone concentration, the temperature, the humidity, and the wind speed;
Including,
In the diagnosis step, an ozone generation rate, which is the number of ozone molecules generated per unit time in a predetermined volume, is calculated based on the ozone concentration, the temperature, the humidity, and a half-life of ozone at the wind speed, and a discharge power of a corona discharge generated in the housing is calculated based on the ozone generation rate.
A method for diagnosing insulation deterioration in rotating electrical machines. an acquisition unit that acquires an ozone concentration, a temperature, a humidity, and a wind speed of the airflow in a housing of a rotating electric machine including a housing, a stator housed in the housing, a rotor housed in the housing and rotating relative to the stator, an insulator housed in the housing, and a fan that generates an airflow in the housing;
a diagnosis unit that diagnoses deterioration of the insulator based on the ozone concentration, the temperature, the humidity, and the wind speed of the airflow;
Equipped with
the diagnostic unit calculates an ozone generation rate, which is the number of ozone molecules generated per unit time in a predetermined volume, based on the ozone concentration, the temperature, the humidity, and a half-life of ozone at the wind speed, and calculates a discharge power of a corona discharge generated in the housing based on the ozone generation rate.
Insulation deterioration diagnostic device.

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