JP2003270284A - Winding interlayer short circuit monitoring device for electrical machine and apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a winding interlayer short circuit monitoring device for an electrical machine and apparatus for always monitoring the interlayer short circuit from a viewpoint of a preventive maintenance and predicting the occurrence of the short circuit. <P>SOLUTION: The winding interlayer short circuit monitoring device for the electrical machine and apparatus comprises a zero-phase current transformer 9 clamped to a power line of the apparatus having a winding to detect an interlayer short circuit pulse generated from the power line, a pulse amplifying unit 31 for processing to extract an interlayer short circuit pulse current detected by the transformer, a level setting unit 32 for judging that an amplitude and occurring frequency of the pulse processed by the amplifying unit exceed predetermined levels, and a warning unit 33 for generating an alarm when the amplitude and the frequency of the amplifying unit exceed the set levels in the judgment of the setting unit. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric machine for constantly monitoring a rare short circuit generated in a coil winding of a rotating machine such as a drive motor for an elevator or a compressor motor for an air conditioner, a transformer, or a reactor or the like. A winding rare short monitoring device for equipment.

[0002]

2. Description of the Related Art FIG. 4 shows a conventional inspection method of this type for diagnosing the insulation state of a lift drive motor, an air conditioning compressor motor, and the like. In the figure, 1 is a motor M which is an electric device including a winding to be diagnosed, 2 is a power supply line for supplying a three-phase AC voltage to the motor 1, and 3 is a breaker MCCB or an electromagnetic device for opening and closing the three-phase AC voltage. This is a switch composed of a contactor MC, and the operation of the motor 1 is controlled by supplying the voltage whose switching is controlled to the terminal board 4 of the motor 1.

In the case of diagnosing the deterioration of the motor over time, the most frequently used method is the power supply line 2 shown in FIG.
After opening the switch 3 provided in the switch, temporarily stopping the motor and disconnecting it from the power supply, the lead wire 12 of the insulation resistance meter (Megger) 11 is clipped to one terminal on the secondary side of the switch 3. ,
Connect the other lead wire 13 to the ground wire 6 of the mount 5 of the motor 1.
Clip to.

After that, a voltage output switch button (not shown) of the insulation resistance meter 11 is pressed to read the insulation resistance instruction value, and then the switch button is released to complete the measurement. The degree of progress of insulation deterioration is evaluated based on the measured insulation resistance.

In FIG. 4, ta is measured by an alternating current tan δ meter 21 which is used in combination with the insulation resistance meter 11.
A method of measuring nδ insulation characteristic data is also shown.
Similar to the case of the insulation resistance meter 11, after the lead wires 22 and 23 of the tan δ meter 21 are clipped to the secondary side one terminal of the switch 3 and the ground wire 6 of the gantry 5 of the motor 1, respectively, t
Press the measurement switch (not shown) of the an delta meter 23
Measure the value of δ.

Although tan δ is an index of insulation against alternating current, it has the merit of being able to detect and evaluate local insulation deterioration in principle, so it has recently been reviewed as an inspection method that complements the insulation resistance test, that is, the megger test. There is.

As described above, the conventional insulation inspection method using an insulation resistance meter and the conventional insulation inspection method using a tan δ meter are simple inspection methods. However, this method has caused deterioration of the insulation of the motor winding to be disconnected from the electric circuit. Even after that, it is an effective inspection means under the condition that it remains irreversibly, but the insulation of the motor winding is still in the initial stage of deterioration, and it occurs only while the motor is running, and intermittently. The occurrence of such a rare short pulse discharge could not be detected.

In other words, even a temporary insulation failure that occurs during operation at the initial stage of insulation deterioration cannot be caught by the conventional inspection method because the insulation is reversibly restored when the operation is stopped.

[0009]

As described above, when insulation of a coil winding of a rotating machine such as a drive motor for an elevator or a compressor motor for an air conditioner, a transformer, or an electric device such as a reactor is deteriorated, the inside of the winding is deteriorated. A local rare short circuit occurs. If these rare shorts are left unattended, they will damage the main insulating parts of these electric devices and eventually cause an insulation burnout accident. However, in the conventional insulation inspection method using an insulation resistance meter or the tan δ meter, which is performed after the motor is temporarily stopped and disconnected from the power supply, it is not possible to catch such a local rare short circuit. There was a problem.

The present invention has been made to solve the above problems, and from the viewpoint of preventive maintenance, the winding rare short circuit monitoring for electric equipment which constantly monitors the rare short circuit and predicts its occurrence. The purpose is to provide a device.

[0011]

In view of the above-mentioned object, the present invention is a winding rare short monitoring device for an electric device, which is clamped to a power supply line of an electric device having a winding and is generated in the device. The zero-phase current transformer that detects the rare-short pulse current, the pulse amplification unit that extracts and processes the rare-short pulse current detected by this zero-phase current transformer, and the magnitude of the pulse processed by this pulse amplification unit. For an electric device characterized by comprising a level setting unit for judging that the occurrence frequency exceeds a predetermined level, and an alarm unit for issuing an alarm when the level exceeds the set level in the judgment of the level setting unit. It is in the winding rare short monitoring device.

Further, the pulse amplifying unit includes an amplifying circuit for amplifying a rare short pulse, and an attenuator and a bandpass filter for suppressing an excessive current of a commercial frequency at the time of starting the electric equipment are provided in the preceding stage of the pulse amplifying unit. And at least one integrating circuit for integrating the rare short pulse current.

Further, the level setting unit has a display lamp for displaying a plurality of failure stages classified by a combination of the magnitude and the frequency of occurrence of the rare short pulse in the pulse amplification unit and a cumulative count for each. And a display unit including a display counter.

Further, the alarm unit is characterized by generating a self-holding alarm output capable of outputting a contact signal corresponding to each failure stage.

Further, the level setting unit is characterized in that the determination operation is avoided at the time of starting and decelerating the electric device according to an operation sequence signal from the control panel of the electric device.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiment 1. FIG. 1 is a diagram showing a configuration of a winding rare short monitoring device for an electric device according to an embodiment of the present invention. In FIG. 1, 1 to 6 are the same as those shown in the prior art, and therefore the description is omitted. 7
Is, for example, a control panel of the elevator, 8 is a three-phase power line from the output side of the control panel 7 to the terminal board 4 of the motor 1, and 9 is a zero for detecting rare short pulses collectively clamped to the three-phase power line 8. It is a phase current transformer (ZCT).

[0017] 30 is a monitor for continuously monitoring the short circuit, enter the layer short pulse current i _o from the zero-phase current transformer 9 always partially rare inside windings of the monitored motor 1 An alarm signal s is generated when a short circuit occurs. Reference numeral 31 is a pulse amplification unit that includes an amplification circuit that amplifies the detected rare short pulse current i _o and that performs extraction processing of the pulse current. Reference numeral 32 is a predetermined value in which the magnitude and frequency of occurrence of the extracted pulse are preset. A level setting unit for determining whether the level has been exceeded, and for making a determination based on this, 33 is an alarm unit for notifying the occurrence of a rare short circuit, sq, q, p are control panel 7, pulse amplification unit 31, level Setting unit 3
2 is the output signal. An integrating circuit 3 that integrates the rare short pulse current i _o from the zero-phase current transformer 9 is provided before the pulse amplification unit 31 for the pulse current extraction process.
4 may be provided.

FIG. 2 is a time chart of voltages and signals at various parts of the device shown in FIG. Reference numerals 51 and 52 respectively show a positive cycle waveform and a negative cycle waveform of the waveform of the operating voltage v of the motor 1. An example of the rare short pulse current i _o based on the detection result of the rare short pulse of the zero-phase current transformer 9 of FIG. 1 is as shown in the waveform of i _{o of} FIG. 53 is a rare short pulse current generated in the positive cycle, and in this case, two positive polarity pulses are shown. Reference numeral 54 is a rare short pulse current generated in the negative cycle, and in this case, one negative pulse is shown. In a real case,
The frequency of discharge pulses caused by a rare short circuit at the initial stage of insulation deterioration does not have a continuous pulse pattern for each cycle but has a toothless intermittent pulse pattern.

The signal of the current output i _o of the zero-phase current transformer 9 is shown in FIG.
When it is input to the integration circuit 34 of, and further to the pulse amplification unit 31, the integration signal q is output as an extraction signal.
The waveform is shown as waveform q in FIG. The integration circuit 34 may be included in the pulse amplification unit 31. Reference numeral 55 is a discharge charge pulse which is the time integration of the rare short pulse current 53, and 56 is a discharge charge pulse whose polarity is inverted from that of the negative current pulse of the rare short pulse current 54.

In the level setting unit 32 of FIG. 1, the integrated signal q, which is a discharge charge pulse, is level-set and compared by AND conditions of its magnitude and frequency of occurrence, and the AND condition of magnitude and frequency of occurrence of this signal indicates that a rare short circuit occurs. Is set appropriately to predict in advance.

In a rotating machine such as an ordinary motor, the surface of the winding is exposed to the air, that is, so-called air insulation. In this case, the surface discharge due to surface contamination deterioration or the like is up to about 10 nC. Is a glow discharge having a low discharge plasma density and is harmless to the solid insulator in the winding portion. However, when the discharge charge is about 10 to 100 nC, a streamer discharge having a high discharge plasma density is generated, and when the accumulated number of discharges reaches tens of thousands, a situation such as a penetration breakdown of the solid insulator is caused.

Therefore, from the practical point of view, the following level is selected as the level setting value. Minor failure level: discharge charge 10 nC, occurrence frequency 100 /
10 sec Serious failure level: discharge charge 100 nC, occurrence frequency 500 shots / 10 sec

The alarm unit 33 of FIG. 1 has respective failure levels (level setting unit 32 is divided into two stages, a light failure and a heavy failure) according to a comparison judgment signal p of AND conditions of the light failure and the heavy failure from the level setting unit 32. Not limited to this, it may be divided into a plurality of ranks of three or more ranks.)
By outputting the alarm signal s, which is a self-held display lamp signal or contact signal, the maintenance personnel of the elevator can know the presence or absence of abnormality by the display during inspection, or the contact signal Can be used to exert an online constant monitoring function by remote monitoring.

As described above, according to this embodiment, the insulation of the motor windings of the elevator drive motor, the air-conditioning compressor motor, etc. is at an early stage of deterioration over time, and only while the motor is in operation. Since it is possible to constantly monitor the occurrence of a rare short pulse discharge that occurs intermittently, it is possible to realize a monitoring device that can predict the occurrence of a rare short accident.

Embodiment 2. Moreover, in the above-described embodiment, the rare short pulse current i _o input to the pulse amplification unit 31 is actually a current component whose main component is the leakage current at the commercial frequency during operation of the motor 1, The short pulse component is superposed on this. Since the leakage current at the commercial frequency is usually about 10 mA or less, in order to extract only the rare short pulse current, a bandpass filter 35 is provided at the front stage of the pulse amplification unit 31, that is, at the input side, as shown in FIG. Good. The frequency band wave width is selected to be, for example, 15 to 750 kHz.

Furthermore, a drive motor for elevators such as elevators is frequently started and stopped, and a leak current having a commercial frequency of several hundred mA due to an excessive start current may flow each time. If this transient AC current is large, the operation of the integration / amplification circuit following the bandpass filter becomes unstable, and a ghost parasitic pulse inside the monitoring device, which has nothing to do with the rare short pulse, is generated. May occur.

Therefore, in this embodiment, as shown in FIG. 3, the signal level is attenuated before the band pass filter 35, for example, an attenuator 3 of 1/10 to 1/100.
6 is further installed, and by designing the integrating circuit 34 in the subsequent stage and the amplifying circuit of the pulse amplifying unit 31 with high amplification, a stable leak current integrating function is exhibited even under the above-mentioned excessive AC current. Therefore, it is possible to enhance the effect of the invention of the first embodiment to a more practical area.

Embodiment 3. 1 of the first embodiment.
The level setting unit 32 shown by has a function of recognizing the status of light failure and heavy failure by the combination of the discharge charge which is the size of the rare short-circuit and the generation frequency thereof (steps in a plurality of ranks of three or more steps). It may be divided). In the third embodiment, as shown in FIG.
The level setting unit 32 is provided with a display unit 32a including a display lamp for displaying each of the plurality of failure stages divided into stages, a display lamp for displaying the respective cumulative counts, and a display counter (with a counter function), and allows the maintenance personnel to regularly patrol and During a temporary visit patrol by a remote monitoring alarm, it is possible to know the cumulative number of failures since the previous patrol. Therefore, considering the visual result of the target motor by the patrol officer and the cumulative count of the rare short monitoring device together, whether or not to continue the operation thereafter,
It can provide important material to assist in making decisions about corrective actions to take.

Fourth Embodiment Further, the operation sequence signal sq in FIGS. 1 and 3 is an operation sequence signal for controlling the operation of the target motor 1, for example, starting the motor from the elevator control panel 7, stable operation / motor braking, and the like. The operating current of the motor 1 is more transient and excessive at the time of starting or braking than at the time of stable operation. Therefore, by inputting this operation sequence signal sq to the level setting unit 32, only the stable operation is performed. It is possible to select a time zone and perform rare short monitoring in that time zone (avoid short short monitoring during motor startup, deceleration or braking). In the second embodiment, the attenuator 36 has the effect of preventing an excessive starting current from adversely affecting the monitoring device. However, the same effect is obtained only in the stable operation according to the fourth embodiment. It is obtained by performing a comparison calculation operation with.

In each of the above-described embodiments, the elevator drive motor for an elevator or the like has been described, but the monitoring device according to the present invention includes an air conditioning compressor motor, a general industrial plant motor, and a transformer. It can also be applied to the monitoring of coil winding insulation of stationary equipment such as electric appliances and reactors.
Similar effects are obtained.

[0031]

As described above, according to the present invention, there is provided a winding short-circuit monitoring device for electric equipment, which is a short-circuit pulse generated by clamping a power supply line of electric equipment having windings. A zero-phase current transformer that detects a current, a pulse amplification unit that extracts and processes the rare short pulse current detected by this zero-phase current transformer, and the magnitude and frequency of the pulses processed by this pulse amplification unit are predetermined. Of a winding rare earth for an electric device, comprising: a level setting unit for determining that the level has been exceeded, and an alarm unit for issuing an alarm when the set level is exceeded in the determination of the level setting unit. Since it is a short-circuit monitoring device, rare short pulses that occur intermittently only when the motor is in operation at the initial stage of deterioration of the winding insulation over time It is possible to monitor the occurrence of power at all times, it is possible to predict the occurrence of a rare short-circuit accident.

Further, the pulse amplification unit includes an amplification circuit for amplifying a rare short pulse, and an attenuator and a bandpass filter for suppressing an excessive current of the commercial frequency at the time of starting the electric equipment are provided in the preceding stage of the pulse amplification unit. , And at least one integrating circuit for integrating the rare short pulse current, the above-mentioned effect can be obtained even under an excessive AC current. The stable integration function of the leakage current is exerted, so that the above-mentioned effect can be enhanced to a more practical range.

Further, the level setting unit displays a plurality of failure stages which are divided into stages by the combination of the size and the occurrence frequency of the rare short pulse in the pulse amplification unit, and an indicator lamp for displaying the respective cumulative counts. Since it is characterized by the provision of a display unit including a display counter, it is possible to continue operation after that, and measures to be taken, considering the visual result of the target motor by the patrol officer and the cumulative count of the rare short monitoring device. It can provide important material to support treatment decisions.

Further, since the alarm unit is characterized by generating a self-holding alarm output capable of outputting a contact signal corresponding to each failure stage, an online monitoring by remote monitoring using the contact signal is performed. It is possible to exert a constant monitoring function.

Further, the level setting unit is characterized in that the judgment operation is avoided at the time of starting and decelerating the electric device according to the operation sequence signal from the control panel of the electric device, so that only during stable operation. By performing the comparison calculation operation with the level set value, it is possible to prevent an excessive starting current from adversely affecting the monitoring device.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a winding rare short monitoring device for an electric device according to an embodiment of the present invention.

FIG. 2 is a time chart of voltages and signals of respective parts for explaining the operation of the device of FIG.

FIG. 3 is a diagram showing a configuration of a winding rare short monitoring device for an electric device according to another embodiment of the present invention.

FIG. 4 is a diagram for explaining a conventional method for diagnosing the insulation status of a motor or the like of this type.

[Explanation of symbols]

1 motor, 2 power line, 3 switch, 4 terminal board, 5
Frame, 6 ground wire, 7 control panel, 8 three-phase power line, 9
Zero-phase current transformer (ZCT), 30 monitoring section, 31 pulse amplification unit, 32 level setting unit, 32a display section, 33 alarm unit, 34 integrating circuit, 35 bandpass filter, 36 attenuator.

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 2G014 AA03 AA15 AA16 AB04 AB07                       AB49 AC15                 2G016 BA03 BA04 BB03 BC02 BD07                       BD08 BD09 BD13                 5G004 AA02 AB02 BA01 CA02 DA01                 5H575 AA03 AA06 BB06 DD03 LL22                       MM02 MM11

Claims (5)

[Claims] 1. A winding rare short monitoring device for an electric device, comprising: a zero-phase current transformer that is clamped to a power supply line of an electric device having a winding to detect a rare short pulse current generated therein. , A pulse amplification unit for extracting and processing the rare short pulse current detected by this zero-phase current transformer, and a level for judging that the magnitude and frequency of the pulses processed by this pulse amplification unit have exceeded a predetermined level. A winding short-circuit short-circuit monitoring device for electrical equipment, comprising: a setting unit; and an alarm unit that issues an alarm when the level exceeds the set level in the judgment of the level setting unit. 2. The pulse amplifying unit includes an amplifying circuit for amplifying a rare short pulse, and an attenuator and a bandpass filter for suppressing an excessive current at a commercial frequency at the time of starting an electric device are provided in the preceding stage of the pulse amplifying unit. And a winding rare short monitoring device for electric equipment according to claim 1, further comprising at least one of an integrating circuit for integrating the rare short pulse current. 3. The indicator lamp for displaying the plurality of failure stages and the cumulative count of each of them, which are classified into stages by the combination of the magnitude and the occurrence frequency of the rare short pulse in the pulse amplification unit by the level setting unit. 3. A winding rare short monitoring device for electric equipment according to claim 1, further comprising a display unit including a display counter. 4. The winding for an electric device according to claim 3, wherein the alarm unit generates a self-holding alarm output capable of outputting a contact signal corresponding to each failure stage. Rare short monitoring device. 5. The level setting unit according to claim 1, wherein the level setting unit avoids the determination operation at the time of starting or decelerating the electric device according to an operation sequence signal from the control panel of the electric device. 2. A winding short-circuit shortage monitoring apparatus for electric equipment according to item 1.