JPS6111540B2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a local overheating diagnosis device for a rotating electrical machine,
In particular, the present invention relates to a device for diagnosing local overheating of a portion covered with a thermally deteriorating organic insulating material, such as a stator core, in a gas-cooled rotating electric machine.

Conventionally, it has been known to provide particulate monitors in generators, particularly large-capacity hydrogen-cooled turbine generators, in order to detect local overheating at an early stage.

Generally, at the initial stage of burnout of a stator core, a part of the core becomes overheated, and organic insulators attached to the core and organic insulators placed near the core, such as varnish applied to the core, become overheated. , the insulation of the coils decomposes thermally and becomes suspended inside the aircraft as fine particles. Therefore, the particulates contained in the refrigerant gas inside the machine increase not only during abnormal heating of the iron core, but also at the initial stage, so by measuring the particulate concentration in the refrigerant gas inside the machine, Abnormal heating can be monitored.

Fig. 1 shows a conventional diagnostic device using such a particulate monitor. The refrigerant gas inside the generator 1 is circulated by a fan 2 attached to the rotor, and a part of the refrigerant gas is circulated by the high pressure of the fan 2. Introduced into the particulate monitor 3 from the gas outlet 4 provided on the side,
After the particulate concentration is checked here, the gas is returned through the gas return port 5 provided on the low pressure side.

The refrigerant gas monitored by the particulate monitor in this way is a gas with an average particulate concentration that circulates inside the machine, and the heating area is small and the temperature is relatively low, as in the early stages of abnormal heating of the iron core. When the amount of particulates is low and the number of particulates generated is small, they are diluted by a large amount of internal circulating gas, making it difficult to distinguish the increase in particulate concentration from other disturbances such as background noise, making early detection of local heating difficult.

In addition, the present inventors have recently discovered that hydrocarbons are generated during thermal decomposition of organic insulating materials, and have measured the concentration of hydrocarbons in refrigerant gas using an analyzer that uses infrared absorption wavelengths. Although a method has been proposed in which local overheating of a rotating electric machine is monitored using a hydrocarbon monitor, the same problems as those described above occur in the monitoring method using the hydrocarbon monitor or in the monitoring method using the hydrocarbon monitor in combination with a particulate monitor.

An object of the present invention is to provide a local overheat diagnosis device for a rotating electric machine that can detect local overheating at an early stage by improving the detection sensitivity of fine particles or hydrocarbons in refrigerant gas, while eliminating the drawbacks of the prior art described above. It is in.

In order to achieve this objective, the present invention focuses on the fact that most of the local overheating of a rotating electrical machine occurs at the end of the stator core, and the present invention has developed a gas outlet for introducing refrigerant gas into the detection device at the end of the stator core. The refrigerant gas containing many particulates and hydrocarbons passing near the end of the stator core is introduced into the detection device while being distinguished from other circulating gases. do.

Generally, the end portion of the stator core of a generator tends to have a higher temperature than other portions because the field magnetic flux generated by the rotor concentrates thereon. To prevent this, the second
As shown in the figure, the inner diameter of the core is gradually increased in multiple steps as it approaches the end, over a range of about 20 cm at the end of the core, so-called "paralleling" is carried out to increase the magnetic resistance in this area and to increase the magnetic flux. Measures are taken to reduce loss and temperature rise by cutting slits 7 in the teeth of the core 6 over a range of about 10 cm at the end of the core to narrow the range of the core where eddy currents flow. It's straining. Furthermore, the second
In the figure, 8 is an end duct and 9 is an air duct.

However, when the slits 7 are cut in this way, the rigidity of the iron core decreases, and the insulation coating between each iron plate is damaged due to mechanical and electromagnetic vibrations of the iron core, leading to the risk of short circuits occurring between each iron plate. is high. Normally, the entire core with slits is bonded and solidified with adhesive to increase rigidity, but even so, the slitted core ends are more prone to short circuits between steel plates than other core parts. easy. In addition, if the core ends are stepped as described above, the tightening surface pressure will decrease, which will also generate mechanical and electromagnetic vibrations, causing deterioration of the insulation coating between the steel plates and This can easily cause a short circuit. Note that if these measures are not taken, the temperature at the end of the iron core will rise, promoting deterioration of the insulation coating between the iron plates, and short circuits between the iron plates will likely occur.

An embodiment of the present invention will be described below with reference to FIG.

In Figure 3, 1 is a generator, 2 is a fan, 3
is a particle monitor, 4 is a hydrogen gas outlet, 5 is a hydrogen gas return port, 6 is a stator core, 8 is an end duct,
10 is a rotor, and 11 is a heat exchanger.

The hydrogen gas filled in the generator 1 is transferred to the rotor 1
The fan 2 attached to the stator core 6
The heated gas is circulated through a duct provided in the rotor 10 as shown by the broken line arrows, and after cooling each part, the warmed gas is cooled in a heat exchanger 11 and circulated again by a fan 2. Ru.

By the way, in this embodiment, the hydrogen gas outlet 4
extends inward to near the outer periphery of the stator core 6 end where the hydrogen gas that has passed near the stator core 6 end is discharged, and discharges the hydrogen gas that has passed near the stator core 6 end to other parts. The hydrogen gas is introduced into the particle monitor 3 separately from the hydrogen gas that has passed through the particle monitor 3.

Therefore, local overheating occurs at the 6 ends of the stator core (as mentioned above, most of the local overheating in rotating electric machines occurs at the ends of the stator core), and thermal decomposition of the organic insulating material occurs. If particulates are generated, the hydrogen gas containing the particulates that passes through the end of the iron core will not mix with the large amount of hydrogen gas that has passed through other normal parts of the machine, and will not be diluted. Since the particles are introduced into the particle monitor 3 in a high concentration state, the particle concentration can be detected with high sensitivity, and local overheating can be detected early and reliably.
In addition, since the hydrogen gas introduced into the particulate monitor does not pass through the heat exchanger 11 as in the conventional case, the particulates contained in the hydrogen gas are adsorbed by the heat exchanger 11. There is no decrease in concentration.

In the above-mentioned embodiment, a case was explained in which a particulate monitor was used as a monitor for monitoring local overheating. However, the present invention is not limited to this, and the present invention is not limited to this. The same application can be made when a monitor is also used.

In addition, since the ends of the stator core are on both sides in the axial direction, it is desirable to monitor gas from both sides.Furthermore, it is desirable to monitor gas that has passed not only at the ends of the stator core but also through other parts. It is preferable that the system be monitored by another separate monitor.

As explained above, according to the present invention, the refrigerant gas passing near the end of the stator core, where local overheating occurs frequently, is introduced into the detection device while being distinguished from other circulating gases. If this occurs, the detection sensitivity of particulates or hydrocarbons in the refrigerant gas can be increased, so that local overheating can be detected early and reliably, and its reliability can be improved.

[Brief explanation of drawings]

Fig. 1 is a schematic configuration diagram of a conventional local overheating diagnosis device using a particle monitor, Fig. 2 is a perspective view showing the end of a stator core of a rotating electric machine, and Fig. 3 is a local overheating diagnosis according to an embodiment of the present invention. It is a schematic block diagram of the generator provided with the apparatus. 1... Generator, 2... Fan, 3... Particulate monitor, 4... Hydrogen gas outlet, 5... Hydrogen gas return port, 6... Stator core.

Claims (1)

[Claims] 1. A gas-cooled rotating electric machine having a stator core covered with an organic insulating material that thermally decomposes and generates fine particles and hydrocarbons in the refrigerant gas when exposed to high temperatures; and and a detection device that detects the concentration of at least one of the hydrocarbons, and diagnoses that local overheating has occurred in the rotating electric machine when the detected concentration of the detection device exceeds a predetermined value. A local overheat diagnosis device for a rotating electrical machine, characterized in that a gas outlet for introducing the gas into the detection device extends to near the outer periphery of an end of the stator core.