JPH01191071A - Monitoring method for rotary electric machine - Google Patents

Abstract

PURPOSE:To correctly grasp the status of a corona discharge by attenuating a high frequency electric quantity which is based on a electric discharge taken out from electric power source lines for a rotary electric machine, down to a level suitable for detection in the detecting means through attenuation means and thereby detecting the same. CONSTITUTION:When the corona discharge is generated during the operation of the rotary electric machine 1, the high frequency currents are made to flow in the power source lines 3 and taken out through coupling capacitors 51-53. In case the high frequency currents taken out from the capacitors 51-53 are large, these currents are adjusted to the amounts suitable for the detection by the operation of variable resistance attenuators 61-63 and supplied to detectors 71-73. Outputs from the detectors 71-73 are supplied to a filter 10 by a changeover switch 9 for every phase, wherein noise from by power source and noises of a broadcasting wave, electromagnetic induction, etc., are removed, then the output of the filter 10 is supplied to a corona measuring instrument 12 for the measurement through a resistance attenuator 11. The status of the corona discharge is thus correctly grasped.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a method for monitoring a rotating electrical machine, which monitors insulation deterioration of the windings of the rotating electrical machine while it is in operation.

(Prior Art) Conventionally, as a method for determining the insulation deterioration of a rotating electric machine, for example, for a stator, after stopping the operation of the rotating electric machine, a high voltage is applied to the windings, and various electrical characteristics (insulation resistance, An electrical method is used to estimate the degree of deterioration of the insulation in each part by measuring alternating current, dielectric loss angle 15 partial discharge, etc. A mechanical method is used in which the coil is removed and the state of mechanical damage to the insulation part and the state of deterioration of the winding fixing force are determined by visual inspection and sound.

However, in order to determine deterioration using these methods, it is necessary not only to stop the operation of the rotating electric machine but also to disconnect the line, and in some cases, it is also necessary to perform operations such as removing the rotor. For this reason, performing deterioration determination using such a series of methods requires a great deal of time, effort, and expense, and has the drawback that it is difficult to conduct deterioration determination tests frequently. In addition, implementing this method requires time for preparation, so it has the disadvantage that it cannot adequately deal with cases where deterioration progresses rapidly.

Therefore, in the past, in order to eliminate such inconveniences, devices have been devised that allow deterioration judgment to be made without stopping the operation of rotating electric machines.For example, coupling capacitors are inserted on the line side of rotating electric machines, and By detecting the high frequency current based on the discharge that occurs when the electric machine is running through a capacitor, and comparing this detection result with the case when the rotating electric machine is stopped,
There is a method that accurately grasps insulation deterioration and winding fixing force deterioration during operation.

However, in the case of a rotating electric machine, the magnitude of external noise differs when it is stopped and when it is running, and in particular, the magnitude of corona discharge is often an order of magnitude larger when it is running. If the detection level of high-frequency current based on discharge is set so that it can be detected optimally when stopped, the input given to the detection means during operation will be excessive, and this will cause the detection means to reach a saturated state. This has the disadvantage that the input waveform becomes a saturated waveform, making it impossible to accurately grasp the actual state of corona discharge, which is detected as various frequencies.

In this way, with conventional methods, the magnitude of corona discharge differs when the rotating electrical machine is stopped and when it is running, so the input to the detection means may become excessive, making it difficult to accurately grasp the state of corona discharge. There was a drawback that it was difficult to do.

Therefore, the object of the present invention is to be able to adjust the detection input given to the detection means to an optimal size.
An object of the present invention is to provide a method for monitoring a rotating electrical machine that can accurately grasp the state of corona discharge.

In this invention, the relationship between the manipulated variable and the attenuated output is confirmed when the high-frequency electrical quantity based on the discharge extracted from the power supply line of a rotating electric machine is attenuated in advance and corresponds to a certain amount of discharge. After the signal is attenuated through the attenuating means to a level optimal for detection by the detecting means, it is detected.

(Function) As a result, it is possible to provide the detection means with an input that has been adjusted to a measurably optimal value that does not cause the input to become excessive, and also to provide the damping operation amount and damping output of the damping means that have been confirmed in advance. It becomes possible to grasp the actual state of corona discharge from the relationship with

(Example) An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a schematic configuration for explaining the same embodiment. In the figure, 1 is a rotating electrical machine to which the same embodiment is applied, and this motor 1 has stator windings 2 of U, V, and W.
Each phase has a winding.

A power line 3 consisting of U, V, and W phases is connected to the stator winding 2, and is connected to a power source (not shown) via a breaker 4.

Each U of the power line 3 connected to the stator winding 2.

Coupling capacitors 51, 52, 53 made of solid capacitors with excellent high frequency characteristics are connected to the vSW phase, and a high frequency current based on the discharge is taken out through these capacitors 51 to 53, and is passed through a variable resistance attenuator 61, 62, 63. and is applied to detectors 71, 72, and 73. Here, the variable resistance attenuators 61 to 63 are operated to attenuate the high frequency current input via the coupling capacitors 51 to 53 when a certain amount of discharge is generated in the standard corona generator 8. The relationship between the output and the attenuated output has been confirmed in advance.

On the other hand, a switch 9 changes over the outputs from the detectors 71 to 73.
is applied to filter 10 via. This filter 10 is
It removes noise from power supplies, broadcast waves, electromagnetic induction, etc. Then, the output that has passed through the filter 10 is given to a corona measuring device 12 via a resistance attenuator 11. Here, for the resistance attenuator 11 as well, the relationship between the attenuation operation amount and the attenuation output is confirmed in advance, similarly to the variable resistance attenuators 61, 62, and 63 described above.

It should be noted that the detection outputs from the detectors 71 to 73 or the measurement results from the corona measuring device 12 provided via the changeover switch 9 are also provided to the synchroscope 14 via the changeover switch 13.

If corona discharge occurs during operation of the rotating electrical machine 1, a high frequency current flows through the power supply line 3, and this current is taken out via the coupling capacitors 51-53. here,
When the high frequency current taken out from the coupling capacitors 51-53 is large, it is adjusted to the optimum magnitude for detection by operating variable resistance attenuators 61-63 and is applied to detectors 71-73. Further, the outputs from these detectors 71 to 73 are sent to a filter 10 for each phase by a changeover switch 9. Then, after removing noise from the power source, broadcast waves, electromagnetic induction, etc., the signal is applied to the corona measuring device 12 via the resistance attenuator 11 for measurement. In this case as well, if the input to be applied to the corona measuring device 12 via the filter 10 and measured by the corona is large, it will be adjusted to the optimum magnitude by the resistance attenuator 11.

In this case, the detection outputs from the detectors 71 to 73 or the measurement results from the corona measuring device 12, which are given via the changeover switch 9, are also given to the synchroscope 14 through the changeover switch 13 for display. .

Therefore, if this is done, the amount of corona generated in the rotating electric machine may be orders of magnitude larger during operation than when it is stopped due to winding vibrations, etc. In such cases, the synchroscope 14 Variable resistance attenuators 61 to 63 and resistance attenuator 1 while observing the input waveform.
Since the attenuation operation in step 1 allows optimal input to be given to the detectors 71 to 73 and the corona measuring device 12, it is possible to prevent the inputs given to these detectors 71 to 73 and the corona measuring device 12 from becoming excessive and reaching a saturated state. It is possible to reliably prevent the input waveform from becoming a saturated waveform. Then, the amount of corona discharge detected in this way is
By correcting the relationship between the operation amount and the attenuated output when the high-frequency electric quantity corresponding to the pre-confirmed constant discharge amount in the resistance attenuators 61 to 63 and 11 is attenuated, the actual Since the amount of corona discharge can be known with high accuracy, the actual state of corona discharge detected as various frequencies can be accurately grasped. This makes it possible to monitor the amount of corona discharge generated while the rotating electrical machine is running, which is effective for early detection of deterioration of the winding insulation or deterioration of the winding fixing force in the rotating electrical machine. This can greatly contribute to improving the reliability of electrical machine operation.

It should be noted that the present invention is not limited to the above-mentioned embodiments, but can be implemented with appropriate modifications without changing the gist.

For example, in the above case, when the variable resistance attenuators 71 to 73 that adjust the output from the coupling capacitors 51 to 53 to the optimum value and the resistance attenuator 11 that adjusts the input to the corona measuring device 12 to the optimum value are used. However, the present invention can be realized even if only one of these is used.

[Effects of the Invention] According to the present invention, the amount of high-frequency electricity based on the discharge extracted from the power supply line of the rotating electrical machine is attenuated with the amount of operation when the amount of high-frequency electricity corresponding to a certain amount of discharge is attenuated in advance. The output is attenuated to the optimal level for detection by the detection means through an attenuation means whose relationship with the output has been confirmed, and then detected, and the attenuation means is used to adjust the input to the optimal measurable value that does not cause excessive input. In addition, the actual state of corona discharge can be accurately grasped from the relationship between the attenuation operation amount and attenuation output of the attenuation means, which has been confirmed in advance. The corona discharge inside can be measured with high precision. This makes it possible to monitor changes in the amount of corona discharge while the rotating electrical machine is in operation, making it possible to detect deterioration of the winding insulation and deterioration of the winding fixing force Q at an early stage. This can greatly contribute to improving driving reliability.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram for explaining one embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... Rotating electrical machine, 2... Stator winding, 3... Power line, 51-53... Coupling capacitor, 61-63.
...Variable resistance attenuator, 71-73...Detector, 8...
・Standard corona generator, 10...filter, 11...
Resistance attenuator, 12... corona measuring device, 14... synchroscope. Applicant's agent Patent attorney Takehiko Suzue Figure 1

Claims (1)

[Claims] Attenuation means in which the relationship between the manipulated variable and the attenuated output is confirmed when the high-frequency electrical quantity based on the discharge extracted from the power supply line of the rotating electric machine is attenuated in advance, and the high-frequency electrical quantity corresponding to a certain discharge quantity is attenuated. 1. A method for monitoring a rotating electrical machine, characterized in that measurement is performed after the attenuation has been reduced to an optimal level for detection by a detection means.