JPS6114731B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a stator core overheat detection device for a rotating electrical machine, and more particularly to an overheat detection device that detects abnormal overheating of a stator core by taking into account operating conditions other than stator core temperature.

Generally, a stator core of a rotating electric machine is constructed by laminating thin iron plates and tightening and fixing the thin iron plates to a stator frame with tightening bolts via a stator core holding plate. Incidentally, in recent years, large-scale rotating electric machines such as turbine generators have a strong tendency to increase in capacity due to advances in insulation and cooling technology, and at the same time, there is a strong demand for improved reliability.

In particular, the stator core, which is the backbone of rotating electric machines,
The magnetic flux density within the core is approaching saturation, the density of loss is also high, and the possibility of core burnout or dielectric breakdown of adjacent armature windings is extremely high. For this reason, various methods and devices have been proposed for preventing the above-mentioned accidents by monitoring the temperature of the iron core.

FIG. 1 shows an example of a schematic block diagram of a generally used stator core temperature monitoring device.

A signal from the stator core temperature detection device 1 is converted into an appropriate analog or digital amount using a converter 2. The comparison controller 3 then compares the signal with the signal from the reference setting device 4, and if it exceeds the reference value, it is displayed on the monitoring device 5. Then, in the monitoring device 5, a control signal corresponding to the operating conditions of the machine is transmitted to the comprehensive monitoring and control device 6. Generally, the setting value of the reference setting device 4 is set to multiple reference values such as an alarm generation level for iron core temperature rise and a limit temperature level, each of which generates an alarm display, load reduction, or operation stop signal. There is.

By the way, in such a conventional system, a control signal such as an alarm is not transmitted unless the temperature rise of the stator core exceeds a certain level.

FIG. 2 shows the actual load condition, stator core tooth temperature Tt, and stator core back temperature Ts of a rotating electrical machine, taking the case of a turbine generator as an example. As is clear from Figure 2, the generator output MW
The stator core temperature fluctuates greatly when the reactive power MVAR changes, or when the reactive power MVAR changes even if the generator output MW is constant.

As mentioned above, the stator core is formed by laminating a large number of thin iron plates with insulating surface treatment, so repeated temperature changes in the core can damage the insulating surface treatment of the thin iron plates. This causes an interlayer short circuit between the thin iron plates, causing a local temperature rise, which further expands the destruction of the surface treatment and increases the overheated area, which eventually leads to dielectric breakdown of the adjacent armature windings and burnout of the core. There is a very high possibility that this will develop into a serious accident.

By the way, in the conventional method, control signals such as alarms are not issued unless the temperature of the iron core exceeds a certain level, so if the temperature changes less than the set value I shown in Figure 2, it will not respond to the change in the iron core temperature. No signal can be obtained. Also, as shown by T _t1 in Figure 2,
Even if an interlayer short circuit or the like occurs in the thin iron plate and the iron core temperature increases under the same load conditions, it is not possible to obtain a signal corresponding to these state changes if the temperature is below the set value I.

An object of the present invention is to provide a rotating electric machine that can eliminate the drawbacks of the prior art described above, detect abnormal overheating of a stator core properly and early, and significantly improve the reliability of the operation of the rotating electric machine. The present invention provides a stator core overheat detection device.

To achieve this objective, the present invention has been developed based on the temperature of the stator core, its temperature changes, operating conditions (magnetic flux amount, output state, relative position of the stator and rotor in the width direction, cooling conditions, etc.) and its changes. The present invention is characterized in that an evaluation set value of the stator core temperature is determined, and the evaluation set value is compared with the temperature change of the stator core to determine whether or not there is abnormal overheating of the stator core.

Hereinafter, the present invention will be explained in detail based on illustrated embodiments.

FIG. 3 shows a schematic block diagram of an embodiment of the invention.

Signals corresponding to stator core temperature, operating conditions, etc. are detected by a detector 7 and transmitted through a transmission circuit 10 to a converter 2 where they are converted into analog or digital quantities. One of the signals converted by the converter 2 is transmitted to the storage/arithmetic unit 8 and integrated as basic data, and a display signal and a control signal are transmitted to the monitoring device 5 as necessary. The other signal from the converter 2 is transmitted to a change amount calculator 9 that calculates the amount of change in the measured value, and the amount of change in the various measured values is calculated. The signal from the change amount calculator 9 is
The data is transmitted to the comparison controller 3 and the storage calculator 8, and in the storage calculator 8, using various amounts of change and the signals sent from the converter 2, set values for comparison in the comparison controller 3 are determined. calculated. The calculated set value is transmitted to the comparison controller 3 through the transmission circuit 10a, various comparisons and judgments are made, and the results are transmitted to the storage calculator 8 through the transmission circuits 10b and 10c.
and is transmitted to the monitoring device 5, and necessary control signals are transmitted to the comprehensive monitoring and control device 6.

As described above, according to this embodiment, the set value is determined in response to various detected values and the amount of change thereof, so that it is possible to check whether or not there is an abnormality in the stator core corresponding to the operating conditions of the machine. It can be detected properly and early. Therefore, in response to this, changes in operating conditions, adjustment of load conditions, etc. can be appropriately controlled, and the reliability of machine operation can be significantly improved.

FIG. 4 specifically shows an embodiment of the present invention aimed at a turbine generator.

The turbine generator includes a stator core 11, an armature winding 12, a stator frame 13, a rotor 14, a bushing 15 that takes out the output to the outside of the machine, a current transformer 16 that detects the value of output current, etc., and is enclosed inside the machine. It consists of a cooler 17 and the like for cooling the hydrogen gas.

Inside the turbine generator, there are various operating conditions (generator output voltage, current, exciting current, rotation speed, power factor, etc.), mainly a temperature sensing element that detects the stator core temperature.
Elements are installed to measure cooling conditions (hydrogen gas temperature, flow rate, etc.), mechanical conditions (relative position of stator and rotor, vibration, etc.), and electromagnetic conditions (magnetic flux distribution in each part, etc.). Since it is necessary to measure the maximum values of cooling conditions, stator core temperature, and electromagnetic conditions, multiple elements are used at appropriate locations. Acquisition of measurement data takes place through acquisition controller 18 and is transmitted to each transducer 2a-2e. Converters 2a to 2e are used that correspond to the respective detection elements, and convert the detected values into signals corresponding to the detected values. In this case, converter 2a is used to detect the operating conditions, converter 2b is used to detect the stator core temperature,
Further, the converters 2c, 2d, and 2e are used to detect the cooling condition, the mechanical condition, and the electromagnetic condition, respectively.

The signal from the converter 2 is transmitted to the storage calculator 8 through the transmission circuit 10b, and is also transmitted to the change amount calculator 9, where the amount of change in the various measured values described above is calculated. These signals are transmitted to the transmission circuits 10a, 10
The data is transmitted to the display device 19 and the storage/operation unit 8 through c. Here, the amount of change is calculated by storing the output data of the converter each time and finding the deviation from the output data of the current converter.
The deviation may be determined based on a specific time, operating conditions, cooling conditions, etc.

The signal corresponding to the stator core temperature is sent to transmission circuit 1.
It is transmitted to the comparison controller 3 through 0d and enters the comparison controller 3a. In this case, what is input to the comparison controller 3a is the amount of change in temperature calculated by the amount of change calculator 9. The comparison controller 3a determines whether there is a change in the iron core temperature, and if there is no change, a signal is sent to the display device 19 through the transmission circuit, and a next data collection command is sent to the collection controller 18 through the transmission circuit 10e.
transmitted to.

If there is a temperature change, a prediction calculation start command is transmitted to the storage calculator 8 through the transmission circuit 10f, and calculation of a set value corresponding to the operating condition is started.
Predictive calculation is to estimate the temperature of the iron core based on the operating conditions, cooling conditions, mechanical conditions, and electromagnetic conditions that are taken into the storage calculator 8 from the converters 2a, 2c, 2d, and 2e. That is, the iron core temperature is determined by each of the above conditions, but since the heat capacity of the iron core is large, there is a time lag before the iron core reaches a temperature corresponding to those conditions. Therefore, before the iron core temperature actually reaches the temperature corresponding to each of the above conditions, an estimation calculation of the temperature is performed, and this is called a predictive calculation.

Next, the temperature signal of the iron core is sent from the comparison controller 3a to 3.
b, and is compared with a preset limit value for core temperature rise. In this case, the core temperature signal may be the amount of change calculated by the amount of change calculator 9, or may be the signal of the current measurement data of the converter 2b. In the former case, the magnitude of change will be compared, and in the latter case, measured data will be compared. The storage calculator 8 stores limit set values depending on which of these is adopted, and the comparison controller 3b performs a comparison using these set values.
If the temperature exceeds the limit set value (if the absolute value of the iron core temperature exceeds the set value, or if the amount of change shows a sudden change greater than the set value), the transmission circuit 10g
A signal is sent to the alarm 20 through the monitoring device 5.
A control signal is sent from the controller to the comprehensive monitoring device 6. If it is below the limit set value, the comparison controller 3c
The amount of change in temperature is compared with a set value corresponding to the operating condition calculated by the above-mentioned predictive calculation in the storage calculator 8.

As a result of this comparison, it is determined whether or not the core temperature can be predicted. That is, as mentioned above, the core temperature can be predicted to some extent depending on each condition. For example, simply thinking, if you increase the generator output from 50% to 100% depending on the generator load, the iron core temperature will increase due to the increase in generator current, and the electromagnetic conditions due to the increase in current will also increase. This causes the iron core temperature to increase. The change in temperature increase over time can be estimated to some extent based on the above conditions, and the value calculated from this is the set value. However, if the rise in core temperature becomes different from the above-mentioned set value over time, estimation based on the above conditions is no longer possible, and in this case it must be concluded that it is impossible to predict changes in core temperature. I don't get it.

If the comparison controller 3c determines that it is unpredictable, it can be considered that an abnormal phenomenon has occurred, and therefore it is necessary to take appropriate measures. Therefore, the absolute value and change amount signal of the iron core temperature are transmitted from the comparison controller 3c to the comparator 3e through the transmission circuit 10h, and these values are stored in the storage calculator 8 as abnormal phenomenon data, and the degree of abnormality is also stored. and the number of times are determined. In this case, the degree of abnormality is determined, for example, by how much the absolute value of the iron core temperature is relative to a preset alarm level, or by the amount of change in the iron core temperature in response to changes in the generator load. It is determined based on the level of Further, the number of abnormalities is determined based on the determination result of the comparison controller 3c. Based on these determinations, the comparison controller 3c transmits signals of these determination results to the monitoring device 5, if necessary, and the monitoring device 5 determines whether these signals have a margin with respect to the set value. and if there is not enough room, a warning will be issued,
Outputs signals related to generator stop, etc. Furthermore, since these data are affected by changes over time of the machine, etc., they are stored in the storage device of the storage/arithmetic unit 8.

When the comparison controller 3c determines that the prediction is possible, the comparison controller 3c converts the conversion signal or amount of change of the detected value of each temperature detection element in the iron core to the comparison controller 3d.
As a result, the comparison controller compares and examines the presence or absence of a change in the temperature distribution form in the iron core measured last time and the temperature distribution form measured this time. If there is no change in the temperature distribution form, it is determined that there is no abnormality in the iron core temperature change, and a signal is transmitted to the monitoring device 5. When there is a change in the temperature distribution form, a conversion signal of the detection value of each detection element or a signal of the amount of change is transmitted to the comparison controller 3e as an abnormal temperature change. Based on these signals, the comparison controller 3e performs the same process as in the case of determining that temperature change is unpredictable.

FIG. 5 shows a schematic block diagram of the storage arithmetic unit 8 shown in FIG. The signals from the converter 2 and the change amount calculator 9 are transmitted to the transmission circuit 10b,
The data is transmitted to the storage computing unit 8 through 10c. In the storage computing unit 8, the computing unit 8 is used for each signal.
Arithmetic processing is performed by a to 8b.

For example, the operating characteristic curve 21 is
is created, and the driving situation and the amount of change thereof are calculated. Then, it is combined with the change in the magnetic flux B _g in the air gap calculated by the calculator 8d, and the magnetic flux B _g in the air gap is calculated for the preset power factor PF.
The amount of magnetic flux in the air gap is compared with curve 22, and if there is no other change in conditions, a signal corresponding to the power factor and air gap magnetic flux density is sent to the calculator 8f, and a predetermined program is set. The temperature of the iron core is then calculated, and a set value corresponding to the operating state is transmitted to the comparator controller 3.

In addition, when the relative position of the rotor and stator in the axial direction changes due to changes in load conditions,
The amount of change δ _R in the relative position of the rotor and stator at the core end processed by the calculator 8e, the magnetic flux density Be at the core end by the calculator 8d, and the force obtained by the calculator 8a. Using changes in the rate, etc.
Preset iron core end magnetic flux curve 23
In comparison, as described above, the temperature of the iron core is calculated in the computing unit 8f, and the set value is transmitted to the computing unit 3.

As described above, according to this embodiment, the change in stator core temperature is predicted and set based on the set value, various detected values, and the amount of change thereof. An evaluation is made by comparing the set value and the actual amount of change in stator core temperature, so it is possible to determine whether the actual temperature change deviates from the prediction, that is, whether there is an abnormal phenomenon such as overheating in the stator core. It is possible to immediately and easily determine whether or not a temperature has occurred. The presence or absence of an abnormality in the stator core corresponding to the operating conditions can be appropriately and early discovered.

In the embodiments shown in FIGS. 4 and 5, the numbers and combinations of comparison controllers, change amount calculators, and storage calculators are limited, but the present invention is not limited to this. A similar effect can be obtained by changing the parameters.

As described above, according to the present invention, the evaluation setting value for determining the presence or absence of abnormal overheating of the stator core is
It is determined based on various detected values and the amount of change thereof, and is evaluated and judged by comparing this with the actual amount of temperature change, so it is possible to determine whether there is abnormal overheating of the stator core corresponding to the operating conditions of the rotating electric machine. It can be detected properly and early, and the reliability of the operation of the rotating electric machine can be greatly improved.

[Brief explanation of the drawing]

Figure 1 is a schematic block diagram of a conventional stator core temperature monitoring device, Figure 2 is a characteristic diagram showing the relationship between changes in stator core temperature and generator capacity, and Figure 3 is a diagram showing a basic embodiment of the present invention. FIG. 4 is a schematic block diagram of a stator core temperature monitoring device according to a specific embodiment of the present invention, and FIG. 5 is a schematic block diagram of a storage arithmetic unit shown in FIG. 4. It is a block diagram. 2...Converter, 3...Comparison controller, 5...Monitoring device, 7...Detector, 8...Storage calculator, 9...
Change amount calculator, 18... Collection controller.

Claims (1)

[Claims] 1. A rotating electric machine including a stator and a rotor, and a temperature detection device for detecting the temperature of the stator core, and fixed based on the stator core temperature detected by the temperature detection device. In the device for determining whether or not a child core is overheated, an operating condition detection device that detects an operating condition of the rotating electric machine other than the stator core temperature;
a change amount calculation device that calculates the amount of change between the stator core temperature detected by the temperature detection device and the operating condition detected by the operating condition detection device; and the stator core temperature detected by the temperature detection device; an arithmetic device that calculates an evaluation setting value of the stator core temperature from the operating conditions detected by the operating condition detection device, the stator core temperature calculated by the change amount calculation device, and the amount of change in the operating conditions; A rotating electric machine comprising: a comparison and determination device that compares the evaluation set value determined by the change amount calculation device with the amount of change in the stator core temperature calculated by the change amount calculation device to determine whether or not the stator core is overheated. stator core overheat detection device. 2. A stator core overheating device for a rotating electrical machine according to claim 1, wherein the operating condition is an amount of magnetic flux of the rotating electrical machine. 3. A stator core overheat detection device for a rotating electrical machine according to claim 2, characterized in that the operating condition further includes a cooling condition for the rotating electrical machine. 4. A stator core overheat detection device for a rotating electrical machine according to claim 1, wherein the operating condition is an output state of the rotating electrical machine. 5. A stator core overheat detection device for a rotating electrical machine according to claim 4, characterized in that the operating condition further includes a cooling condition for the rotating electrical machine. 6. The stator core overheat detection device for a rotating electric machine according to claim 1, wherein the operating condition is a relative position of the stator and rotor in the axial direction. 7. A stator core overheat detection device for a rotating electrical machine according to claim 6, characterized in that the operating condition further includes a cooling condition for the rotating electrical machine.