JP2002071742A - Partial discharge detector and partial discharge monitoring system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a small-sized, lightweight and inexpensive partial discharge detector capable of monitoring the state of a rotary electric machine in a real time. SOLUTION: The detection signal from the partial discharge sensor 5 provided in the frame of the rotary electric machine is filtered by a narrow band filter 11, of which the center frequency is 5-40 MHz and the pass band width is 1/10-1/3 the center frequency, and the intensity of the maximum partial discharge level, stably generated in each cycle of the voltage frequency applied to the winding of the stator of the rotary electric machine, is measured using a peak detection circuit 12, an analogue/digital conversion memory 13, a display device 14 and a computer 15.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a partial discharge detection device for detecting a partial discharge and a partial discharge monitoring system, and more particularly to a device for detecting a partial discharge of a rotating electric machine on-line in real time.

[0002]

2. Description of the Related Art In recent years, the scale of plants in general industry has been steadily increasing in size, and as a result, the size of rotating electric machines has also increased, and the number of installations has also increased. Therefore, since high reliability is required for such electric equipment, it is necessary to reliably perform maintenance and inspection and to prevent sudden accidents such as insulation breakdown. In particular, the monitoring of the insulation state during operation has become important for electric equipment such as a rotating electric machine, and a technique for continuous monitoring of partial discharge showing insulation properties has been regarded as an important monitoring item. In a rotating electric machine, when deterioration such as cracking or peeling occurs in an insulating layer of a stator winding due to operating stress, a partial discharge occurs in a deteriorated portion due to a voltage during operation. By measuring this partial discharge, the state of deterioration of the insulation is grasped. Since a partial discharge of a rotating electrical machine or the like is generally buried in noise, it is necessary to identify a partial discharge signal and noise and measure only the partial discharge. Conventionally, many methods have been used for measuring the discharge of the deteriorated portion when the insulation is deteriorated by discriminating the partial discharge and the noise and grasping the deterioration state of the insulation.

FIG. 9 is a block diagram of a method for detecting an abnormality of a rotating electric machine disclosed in Japanese Patent Application Laid-Open No. Hei 3-12574. In FIG. 9, reference numeral 101 denotes a three-phase motor, and a three-phase line 103 is connected to each phase winding U, V, and W of a stator 102 of the motor 101. This line 103 is connected as a coupling capacitor to a solid capacitor 104 having a small high-frequency loss. The detector 1 is connected to the solid capacitor 104.
05, changeover switch 106, noise filter 107
And the partial discharge measuring unit 108. Further, the partial discharge measuring unit 108 includes a partial discharge measuring unit 109 for measuring the partial discharge at the start of the motor 101 and the partial discharge during the steady operation, a discharge capturing time control unit 110 for controlling the partial discharge capturing time, and a discharge It is composed of a discharge data storage unit 111 for storing data.

In the above configuration, if insulation deterioration or fixing force deterioration occurs in the windings of the motor, a remarkable difference between the maximum discharge charge amount at the start of the motor and the maximum discharge charge amount at the time of steady operation occurs. Paying attention to the appearance, the partial discharge amount at the start of the motor 101 and the partial discharge amount at the time of steady operation are measured by the partial discharge measuring unit 108, and the difference is compared to compare the difference.
Of the winding of the stator 102 is determined.

[0005] FIG. 10 shows a Japanese Patent Application No. 11-143605.
FIG. 1 is a configuration diagram illustrating an abnormality detection device for a rotating electric machine disclosed in the specification, and measures partial discharge generated due to an abnormality in the rotating electric machine. In FIG. 10, the abnormality detection device selects a plurality of partial discharge detection units 201 and 202 for detecting partial discharges of a plurality of rotating electric machines 200, and selects any one signal from the plurality of partial discharge detection units 201 and 202. Switch 203, a partial discharge measuring means 204 for measuring a signal of the selected partial discharge detecting means, and one of a plurality of partial discharge detecting means 201 and 202 are arbitrarily selected. The determined measurement conditions, judgment conditions,
A computer 205 for performing measurement, noise elimination, insulation diagnosis determination, and data management for each partial discharge detection unit in accordance with the management conditions, and displaying the measurement results;
And a control means 206 for controlling the partial discharge measuring means 204. The partial discharge measuring means 204 has a first narrow band detecting circuit 207 and a second narrow band detecting circuit 208, and the first narrow band detecting circuit 207
And the second narrow band detection circuit 208
Thus, the band is determined for each of the selected partial discharge detection means. The signal of the selected partial discharge detecting means is the first signal.
Narrow-band detection circuit 207 and second narrow-band detection circuit 208
Are passed through the first narrow band detecting circuit 207 and the second narrow band detecting circuit 208, the first narrow band signal and the second narrow band signal are input to the computer 205. The computer 205 compares the first narrow-band signal and the second narrow-band signal to identify and measure the partial discharge.

[0006]

The conventional method for detecting an abnormality of a rotating electrical machine is performed as described above. In the configuration shown in FIG. Since the amount of partial discharge is measured and the measured data is further compared to make an insulation diagnosis determination, there is a problem that real-time output cannot be performed. Further, when measuring the amount of partial discharge at the time of startup and at the time of steady operation, the partial discharge is measured via a noise filter 107 that discriminates between partial discharge and noise. Discrimination between partial discharge and noise is not enough,
The partial discharge amount could not be accurately detected. In the rotating electrical machine abnormality detection device shown in FIG.
The data measured by the partial discharge detection means is passed through two narrow band detection circuits whose bandwidths are determined for each partial discharge detection means by a computer, noise is removed, the two narrow band signals are compared, and the measurement result is output. In addition, there is a problem that real-time output cannot be performed because insulation diagnosis is performed. Further, there is a problem that the configuration of the apparatus is complicated and expensive.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and provides a partial discharge detection device capable of accurately measuring a partial discharge and monitoring a state of a rotating electric machine in real time. The purpose is to do. In the field, only the signal level is grasped and managed, and detailed data can be analyzed in detail by the center computer.
An object is to provide a low-cost partial discharge detection device. It is another object of the present invention to provide a partial discharge monitoring system that can centrally manage partial discharge states during operation of a plurality of rotating electric machines at a center.

[0008]

A partial discharge detecting device according to a first configuration of the present invention is provided in a frame of a rotating electric machine, and detects a partial discharge of the rotating electric machine, and the partial discharge sensor. A partial discharge measuring circuit for filtering the signal detected in step (1) with one filter and measuring and displaying the intensity of partial discharge from the pulse signal filtered in the one filter. The filter is a narrow band filter having a center frequency in the range of 5 to 40 MHz and a pass bandwidth of 1/10 to 1/3 of the center frequency.

Further, the partial discharge detection device according to the second configuration of the present invention, in the first configuration, drives the partial discharge measurement circuit by receiving power from the bus of the rotating electric machine by electromagnetic induction. is there.

The partial discharge detecting device according to a third configuration of the present invention, in the first configuration, includes a battery, and connects the battery to the partial discharge measuring circuit only when measuring the partial discharge. The measurement circuit is driven.

According to a fourth aspect of the present invention, there is provided the partial discharge detecting device according to the first aspect, wherein the partial discharge measuring circuit has a peak detecting circuit, and the voltage frequency applied to the stator winding of the rotating electric machine is different from the first embodiment. The intensity of the maximum partial discharge level stably generated in each cycle is measured and displayed.

A partial discharge detecting device according to a fifth configuration of the present invention, in any one of the first to fourth configurations, includes a communication port for outputting the intensity of the partial discharge measured by the partial discharge measuring circuit; A communication device for transmitting the intensity of the partial discharge to a center computer.

[0013] The partial discharge monitoring system of the present invention comprises:
The partial discharge detection device of the fifth configuration is installed in a plurality of rotating electric machines, and the center computer processes data transmitted from each partial discharge detection device.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 Hereinafter, Embodiment 1 of the present invention will be described with reference to the drawings. FIG. 1 is a configuration diagram showing a partial discharge detection device according to Embodiment 1 of the present invention.
2 and 3 are a cross-sectional configuration diagram and a side view, respectively, of the rotary electric machine according to Embodiment 1 of the present invention. 1 to 3, 1 is a rotating electric machine, 2 is a rotating electric machine frame, 3 is a rotating electric machine rotor, 4 is a rotating electric machine stator, 5 is a partial discharge sensor for detecting partial discharge of the rotating electric machine, and 6 is Lead,
7 is a partial discharge monitor (PD monitor), 8 is a partial discharge measurement circuit (PD measurement circuit), 9 is a level switch, 10 is an amplifier, 11 is a narrow band filter for filtering only a certain frequency range in the MHz band, Here, the passband center frequency is 1
This is a narrow band filter having a bandwidth of 0 MHz and a bandwidth of 3 MHz.
12 is a peak detection circuit, 13 is an analog / digital memory circuit (A / D memory), 14 is a display, 15 is a computer (CPU), 16 is a control bus, 18 is a commercial frequency 100 V driving the partial discharge measurement circuit 8 2 shows a power supply cable from a power supply. The partial discharge monitor 7 according to the first embodiment is installed on the rotating electric machine 1 as shown in FIGS. FIG.
, The partial discharge sensor 5 is provided adjacent to a stator coil (not shown) of the stator 4 of the rotary electric machine 1,
A signal detected by the partial discharge sensor 5 is transmitted via a lead wire 6 to a PD monitor 7 provided outside the frame 2 of the rotary electric machine 1.

In the present embodiment, the amplifier 10 is controlled so as not to be saturated, and only the signal component filtered by the filter 11 out of the signals detected by the partial discharge sensor 5 is measured. FIG. 4 shows an RTD as the partial discharge sensor 5.
(Resistance Temperature D
2 shows the frequency characteristics of the partial discharge pulse and noise when using the “Elector”. In a water turbine generator or a motor having no noise source in the rotating electric machine, in the range of 5 to 40 MHz, the signal of the partial discharge generated in the stator winding has a short propagation distance and is not greatly attenuated and is detected largely. On the other hand, since noise propagates from the outside of the machine, the attenuation of high-frequency components is large.
In the range of 0 MHz, the detection is small. This is particularly noticeable when detecting in a narrow band of about 3 MHz. In the first embodiment, the center frequency fc of the filter 11 is set to 10
MHz. FIG. 5 shows the phase characteristics of the occurrence of partial discharge and noise. FIG. 5A shows a phase characteristic of a typical partial discharge generated in the stator winding. As shown in the figure, the partial discharge occurs at a phase where the change (dv / dt) of the voltage applied to the stator winding is large. FIG. 5B shows the phase characteristics of partial discharge and noise before being filtered by the filter 11. In FIG. 5B, the entire frequency range shown in FIG. 4 is measured. As described above, since the noise in the low frequency range is large before filtering by the filter 11, the partial discharge is buried in the noise and cannot be detected well. FIG. 5C shows the phase characteristics after filtering by the filter 11 of fc = 10 MHz. As shown in the figure, noise is suppressed, and partial discharge can be selectively detected. The peak detection circuit 12 measures the partial discharge larger than the noise shown in FIG. 5C by adjusting the set value of the detection level. The peak value of the signal having the intensity equal to or higher than the set value measured by the peak detection circuit 12 is held in the analog / digital memory circuit 13, converted to digital, and stored. In this way, large pulses per cycle of the commercial frequency are measured and displayed on the display 14.

As is apparent from FIG. 4, the center frequency band of the filter 11 is not limited to 10 MHz, and the same effect can be obtained by selecting a band having a small noise in the range of 5 to 40 MHz. The pass band width of the filter 11 is preferably set to 1/10 to 1/3 of the center frequency.

The same effect can be obtained by using a log amplifier as the amplifier 10.

The installation position of the partial discharge monitor 7 is not limited to the above, and the same effect can be obtained even if the partial discharge monitor 7 is installed in the vicinity of the rotating electric machine 1 where it is easy for a patrol member to see or in the operation room of the rotating electric machine 1. Play.

As described above, according to the present embodiment, since the filter is a narrow band filter in the range of 5 to 40 MHz, the S / N ratio between the partial discharge pulse and the noise is improved, so that the noise is suppressed. Thus, only the partial discharge can be selectively measured. Further, the partial discharge detection device of the present embodiment
It is not to measure the partial discharge and perform detailed analysis to make an insulation diagnosis determination, but to measure and display the intensity of the partial discharge with high accuracy, so that the state of the rotating electric machine can be monitored in real time. In addition, since the partial discharge signal measures large pulses in each cycle of the commercial frequency,
There is an effect that only partial discharges harmful to insulation deterioration can be selectively detected. Furthermore, there is an effect that the measurement circuit can be simplified and the device can be provided at low cost.

Embodiment 2 FIG. 6 is a configuration diagram showing a partial discharge detection device according to Embodiment 2 of the present invention. In FIG. 6, 17 is a plug, 18 is a power cable, 19 is a high-voltage bus for driving a high-voltage motor, 20 is an electromagnetic induction device, and 21 is a power circuit. In the second embodiment, power is electromagnetically obtained by using an electromagnetic induction device 20 provided on a high-voltage bus 19 for driving in the vicinity of the electric motor, and converted to a predetermined DC driving voltage by a power supply circuit 21. Power is supplied to the partial discharge measurement circuit 8 via the power cable 18. The operation of the partial discharge measurement circuit 8 is the same as that of the first embodiment. According to this structure, electric power is supplied from the high voltage bus 19, so that a 100 V commercial frequency power supply is not required. Therefore, the wiring work can be simplified and can be installed at a low cost. In addition, there is an effect that it is easy to install the partial discharge detection device in a rotating electric machine, such as a circulating water pump or a seawater pump, at a power intake of a power plant, where it is difficult to lay 100 V on an existing machine.

The second embodiment can be applied not only to a high-voltage motor but also to a rotating electric machine such as a generator. The bus 19 when applied to a generator is a phase-separated bus that transfers power from the generator to the main transformer. Similarly to the above, power is obtained electromagnetically using an electromagnetic induction device 20 provided on the bus 19 near the rotating electric machine, converted into a predetermined DC drive voltage by a power supply circuit 21, and To supply power to the partial discharge measurement circuit 8.

Embodiment 3 FIG. FIG. 7 is a configuration diagram showing a partial discharge detection device according to Embodiment 3 of the present invention. In FIG. 7, reference numeral 22 denotes a battery, for example, a battery.
In the third embodiment, the battery 22 is provided as a driving power source for the partial discharge measurement circuit 8, and the battery 22 is connected to the partial discharge measurement circuit 8 only when the partial discharge is measured. Drive it. The partial discharge measurement circuit 8 only needs to operate when reading a signal. Therefore, the power supply configuration of the partial discharge detection device is a battery, and the power plug 17 is connected only during measurement, and disconnected when measurement is not performed. This eliminates the need for power supply wiring, simplifies the operation, and allows the apparatus to be installed at low cost. Only one battery 22 is required for a plurality of partial discharge detection devices, and the economic effect is large.

Embodiment 4 In the fourth embodiment, the partial discharge measurement circuit 8 shown in FIGS. 1, 6, and 7 will be described in more detail. The holding time in the peak detection circuit 12 is set to 100 μs by the computer 15.
After that, the digital value is converted after holding the maximum value between them. Further, by adjusting the set value of the detection level of the peak detection circuit 12, about 10 large pulses per cycle of the commercial frequency are measured. The generated partial discharge pulse is captured for one second, the captured pulses are counted in descending order, and the magnitude of the 60th pulse is displayed for two seconds. The measurement is performed for one second in parallel during the display, and the magnitude of the 60th pulse is similarly obtained. In this way, the measurement is performed for one second once every two seconds, and the display is repeated for two seconds. Although the discharge is measured every second, the partial discharge of the rotating electric machine is stably generated, which is sufficient for the partial discharge measurement.

As described above, in the partial discharge measuring circuit 8 of the present embodiment, about 10 large partial discharge pulses in each cycle of the commercial frequency are measured, and the generated partial discharge pulses are captured for 1 second. Since the pulses are counted in descending order and the magnitude of the 60th pulse is displayed, the intensity of the maximum partial discharge level stably generated in each cycle of the voltage frequency applied to the stator winding of the rotating electric machine Is measured, and there is an effect that the measurement circuit can be simplified and the device can be provided at low cost. In addition, there is an effect that only partial discharge harmful to insulation deterioration of the stator winding of the rotating electric machine can be selectively measured. In addition, since the display is performed for 2 seconds, it can be sufficiently read by visual observation.

The holding time is not limited to 100 μm, but may be changed to measure 1 to 10 large pulses per cycle. Needless to say, the measurement time is not limited to one second or the display time is two seconds. In the discharge level display, the 60th magnitude of the digital value measured for one second is displayed, but the same effect can be obtained by displaying the maximum discharge level in an analog manner. Further, in the present embodiment, a large pulse is measured in each cycle of the commercial frequency. However, a large pulse is measured in each cycle of the voltage frequency applied to the stator winding of the rotating electric machine. I just need.

Embodiment 5 FIG. 8 is a configuration diagram showing a partial discharge detection device and a partial discharge monitoring system according to a fifth embodiment of the present invention. 8, reference numeral 23 denotes a communication port for outputting the intensity of the partial discharge measured by the partial discharge measurement circuit 8, and reference numeral 24 denotes a communication device for transmitting the intensity of the output partial discharge to the center computer 25.

Next, the operation of this embodiment will be described. Digital data for one second can be recorded in the A / D memory 13, and the latest data is repeatedly overwritten and recorded. The communication device 24 is connected to the communication port 23, and the latest data recorded in the A / D memory 13 is transmitted to the center computer 25 using the communication means 24 in accordance with a command from the communication device 24. The communication data is transmitted with the name of the rotating machine and the date and time of measurement added. A signal from a partial discharge detection device provided in another rotating electrical machine (machine B in FIG. 8) is also transmitted to the center computer 25, and data of many rotating electrical machines 1 are integrated. The communication means may be any of a PHS, a mobile phone, and an ordinary public line.

With such a configuration, it is possible to grasp the partial discharge state during operation of a large number of rotating electric machines at the center, and to classify them by insulation deterioration factors such as the classification of the rotating electric machines and the type of use. As a result, insulation diagnosis can be determined, and data management of the rotating electric machine for each classification can be performed. In addition, since only the signal level is grasped and managed at the site, a small, light, and low-cost partial discharge detection device can be obtained.
A partial discharge detection device capable of performing insulation diagnosis determination at the center is obtained.

[0029]

As described above, according to the partial discharge detecting device of the first configuration of the present invention, the partial discharge sensor provided in the frame of the rotating electric machine for detecting the partial discharge of the rotating electric machine, A partial discharge measuring circuit for filtering a signal detected by the partial discharge sensor with one filter, and measuring and displaying the intensity of the partial discharge from the pulse signal filtered by the one filter. Since the above-mentioned filter is constituted by a narrow-band filter having a center frequency in the range of 5 to 40 MHz and a pass bandwidth of 1/10 to 1/3 of the center frequency, the noise is suppressed and the partial discharge is selected. This makes it possible to measure the condition of the rotating electric machine in real time and to monitor the state of the rotating electric machine in real time.

Further, according to the partial discharge detecting device of the second configuration of the present invention, in the first configuration, the partial discharge measuring circuit is driven by receiving power from the bus of the rotating electric machine by electromagnetic induction. Therefore, the wiring work can be simplified and the installation can be performed at a low cost.
There is an effect that it becomes easy to install the partial discharge detection device on the rotating electric machine in which the V laying work is difficult.

According to the partial discharge detecting device of the third configuration of the present invention, the first configuration has a battery,
The battery is connected to the partial discharge measurement circuit only when the partial discharge is measured, and the partial discharge measurement circuit is driven. Therefore, the power supply wiring is not required, the configuration can be simplified, and the apparatus can be installed at low cost.

According to the fourth aspect of the present invention, in the first configuration, the partial discharge measuring circuit has a peak detecting circuit and is applied to the stator winding of the rotating electric machine. Since the intensity of the maximum partial discharge level that occurs stably in each cycle of the voltage frequency is measured and displayed, the measurement circuit can be simplified, and partial discharge that is harmful to the insulation deterioration of the stator windings of the rotating electric machine. There is an effect that only measurement can be selectively performed.

According to the fifth aspect of the present invention, in any one of the first to fourth configurations, the communication port for outputting the intensity of the partial discharge measured by the partial discharge measuring circuit. And a communication device for transmitting the intensity of the partial discharge to the center computer.
There is an effect that a low-cost partial discharge detection device can be obtained and insulation diagnosis can be determined at the center.

Further, according to the partial discharge monitoring system of the present invention, the partial discharge detection device having the fifth configuration is installed in a plurality of rotating electric machines, and the center computer processes data transmitted from each partial discharge detection device. Therefore, only the signal level can be grasped and managed at the site, and the partial discharge state during operation of a large number of rotating electric machines can be managed collectively at the center.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a partial discharge detection device according to a first embodiment of the present invention.

FIG. 2 is a sectional configuration diagram showing the rotating electric machine according to Embodiment 1 of the present invention;

FIG. 3 is a side view showing the rotary electric machine according to Embodiment 1 of the present invention;

FIG. 4 is an explanatory diagram illustrating an operation of the partial discharge detection device according to the first embodiment of the present invention.

FIG. 5 is an explanatory diagram illustrating an operation of the partial discharge detection device according to the first embodiment of the present invention.

FIG. 6 is a configuration diagram showing a partial discharge detection device according to a second embodiment of the present invention.

FIG. 7 is a configuration diagram showing a partial discharge detection device according to a third embodiment of the present invention.

FIG. 8 is a configuration diagram showing a partial discharge detection device and a partial discharge monitoring system according to a fifth embodiment of the present invention.

FIG. 9 is a configuration diagram illustrating a conventional abnormality detection method for a rotating electric machine.

FIG. 10 is a configuration diagram showing another conventional abnormality detection device for a rotating electric machine.

[Explanation of symbols]

1 rotating electric machine, 2 frames, 3 rotors, 4 stators, 5 partial discharge sensors, 6 lead wires, 7 partial discharge monitor, 8 partial discharge measurement circuit, 9 level switch, 1
0 amplifier, 11 narrow band filter, 12 peak detection circuit, 13 analog / digital memory circuit, 14 display, 15 computer, 16 control bus, 17 plug, 18 power cable, 19 high voltage bus, 20
Electromagnetic induction equipment, 21 power supply circuit, 22 battery, 23 communication port, 24 communication device, 25 center computer, 10
1 three-phase motor, 102 stator 102, 103 three-phase line, 104 solid capacitor, 105 detector, 10
6 Changeover switch, 107 Noise filter, 10
8 Partial discharge measurement unit, 109 Partial discharge measurement unit, 110
Discharge capture time control unit, 111 discharge data storage unit, 200 rotating electric machine, 201, 202 partial discharge detection means, 203 switch, 204 partial discharge measurement means, 2
05 computer, 206 control means, 207 first
, A second narrow band detection circuit.

Claims (6)

[Claims] 1. A partial discharge sensor provided in a frame of a rotating electric machine and detecting a partial discharge of the rotating electric machine, a signal detected by the partial discharge sensor is filtered by one filter, and the signal is filtered by the one filter. A partial discharge measuring circuit for measuring and displaying the intensity of the partial discharge from the filtered pulse signal, wherein the filter has a center frequency in a range of 5 to 40 MHz and a pass band width of A partial discharge detection device comprising a narrow band filter having 1/10 to 1/3 of the center frequency. 2. The partial discharge detection device according to claim 1, wherein the partial discharge measurement circuit is driven by receiving power from the bus of the rotating electric machine by electromagnetic induction. 3. The partial discharge according to claim 1, further comprising a battery, wherein the battery is connected to the partial discharge measurement circuit only when the partial discharge is measured, and the partial discharge measurement circuit is driven. Detection device. 4. The partial discharge measurement circuit has a peak detection circuit, and measures the intensity of the maximum partial discharge level that is generated stably in each cycle of the voltage frequency applied to the stator winding of the rotating electric machine. 2. The partial discharge detection device according to claim 1, wherein the partial discharge is displayed. 5. A communication port for outputting the intensity of the partial discharge measured by the partial discharge measurement circuit, and a communication device for transmitting the intensity of the partial discharge to a center computer. 5. The partial discharge detection device according to any one of 4. 6. The partial discharge detecting device according to claim 5, wherein the partial discharge detecting device is installed in a plurality of rotating electric machines, and a center computer processes data transmitted from each partial discharge detecting device. Monitoring system.