KR20010007039A - Device for detecting partial discharge - Google Patents

Abstract

PURPOSE: To provide a partial discharge detecting device capable of dispensing with a transformer or a current transformer for extracting a frequency of power flowing in electric power facility, and its phase information and being installed in the existing electric power facility easily. CONSTITUTION: This detecting device is provided with a means 1 detecting electromagnetic waves in accordance with partial discharge generated due to the deterioration of insulation in electric power facility, a means 3 detecting a peak value of an electric signal which is the electromagnetic wave detected by the means 1, a first comparator 4 which compares the peak value detected by the means 3 with a first predetermined value and outputs a signal when the peak value is larger than the first predetermined value, signal generation circuits 11, 4a generating and outputting a signal for detecting a synchronization condition of electric power supplied to the electric power facility and the signal outputted by the first comparator 4 based on the signal outputted by the first comparator 4, a means 5 which detects a synchronization condition of the signals outputted by the first comparator 4 and the signal generation circuits 11, 4a, respectively, and judges the occurrence of partial discharge based on the detected synchronization condition, and a means 6 outputting an alarm based on the judgement of the means 5.

Description

Partial Discharge Detection Device {DEVICE FOR DETECTING PARTIAL DISCHARGE}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a partial discharge detection device for detecting a partial discharge generated by insulation deterioration in a power facility in a state of non-contact with the power facility by an antenna or a high frequency current transformer.

In order to prevent the short-circuit accident and the short circuit accident by the insulation deterioration in electric power equipment, it is generally performed to detect the partial discharge by the insulation deterioration. As a method for monitoring the partial discharge in a non-contact state, a method of detecting electromagnetic waves accompanying the partial discharge by an antenna and a method of detecting a current flowing through the main circuit of the power equipment by the high frequency current transformer in accordance with the partial discharge are effective.

7 is a block diagram showing a configuration example of a conventional partial discharge detection device. The partial discharge detection device has an antenna 1 for detecting electromagnetic waves caused by partial discharge caused by insulation deterioration in a power facility, and a high frequency that amplifies an electric signal due to electromagnetic waves detected by the antenna 1 to a level that is easy to process. The peak detection circuit 3 (for example, the diode 3a and the condenser 3b) which detects the peak value (peak value) of the amplifier 2 and the electrical signal amplified by the high frequency amplifier 2 (or Quasi-peak detection circuit). As an alternative to the antenna 1, a high frequency current transformer that detects a current flowing in the main circuit of the power equipment in accordance with partial discharge may be used.

The partial discharge detection device further includes a comparator 4 for comparing a peak value detected by the peak value detection circuit 3 with a predetermined value and outputting a signal when the peak value is larger than the predetermined value, and a main circuit of the power equipment. Current transformer 8 (or transformer) for detecting the current (or applied voltage) flowing in the conductor 7 and power source frequency extraction for extracting the frequency of the current detected by the current transformer 8 and outputting the signal of the extracted frequency. The circuit 9 (same function as the comparator 4) and the comparator 4 and the power source frequency extraction circuit 9 detect the synchronous state of the signals respectively output to the power equipment based on the detected synchronous state. The signal processing part 5 which determines that partial discharge generate | occur | produced, and the alarm generation part 6 which outputs an alarm by the determination of the signal processing part 5 are provided.

The above-described high frequency amplifier 2, peak value detection circuit 3, comparator 4, power source frequency extraction circuit 9, signal processor 5 and alarm generator 6 are partial discharge signal processor 10. ).

The operation of the conventional partial discharge detection device having such a configuration will be described below.

If insulation deterioration occurs in the power equipment, partial discharge occurs in a portion where insulation deterioration occurs. The current flowing by this partial discharge becomes an impulse current. The antenna 1 detects electromagnetic waves generated by this impulsive current. When a high frequency current transformer is used instead of the antenna 1, current flowing through the main circuit of the power equipment is detected in accordance with partial discharge.

The high frequency amplifier 2 amplifies the electric signal by the electromagnetic wave detected by the antenna 1 to a level that is easy to process. The peak value detection circuit 3 detects the peak value of the electric signal amplified by the high frequency amplifier 2 and supplies it to the comparator 4. The comparator 4 compares the supplied peak value with a predetermined value and outputs a signal when the peak value is larger than the predetermined value.

Since the integrated value of the output signal of the comparator 4 has a correlation with the partial discharge current or the partial discharge charge, when the detection accuracy of the partial discharge may be low, the signal processing unit 5 outputs the output signal of the comparator 4. Is integrated for a predetermined period of time, and when the integrated value becomes equal to or greater than the predetermined value, the alarm can be output from the alarm generating unit 6, thereby achieving the object sufficiently.

However, when disturbances (mixing of broadcast radio waves, etc.) are to be removed and partial discharges must be detected with higher accuracy, the generation phase of the partial discharges must be analyzed within the period of the current flowing through the power equipment.

For this reason, the current transformer 8 detects a current flowing through the main circuit conductor 7 of the power equipment, and the power source frequency extraction circuit 9 extracts the frequency (50 Hz or 60 Hz) of the detected current and extracts the extracted frequency. Outputs the signal of. The signal processing unit 5 detects the synchronous state from the frequency and phase of the signal output by the comparator 4 and the power source frequency extracting circuit 9, respectively, and determines that the part where both are synchronized is partial discharge. The alarm generating unit 6 outputs an alarm when the signal processing unit 5 determines the occurrence of partial discharge.

As described above, in the conventional partial discharge detection device, in order to extract the frequency and phase information of the power supplied to the power facility, it is necessary to install a transformer or a current transformer, so that the partial discharge detection device is installed in the already installed power facility. There was a problem that it was difficult.

As for a technique for detecting partial discharge, an electrical apparatus insulation diagnostic device disclosed in Japanese Patent Laid-Open No. 8-327686, which detects an average signal level of electromagnetic waves due to partial discharge and compares it with a reference value. The frequency spectrum of the detected electromagnetic wave disclosed in Japanese Unexamined Patent Publication No. 6-201754, "Method of detecting partial discharge of electric equipment", which detects electromagnetic waves by partial discharge according to the frequency of the extra channel of television broadcasting, From this, the "component partial discharge detection method of electrical equipment and the partial discharge detection apparatus of electrical equipment" etc. which compare and accumulatively integrate the band component of a communication wave, and compare with the normal cumulative integration spectrum can be mentioned.

The present invention has been made in view of the above circumstances, and there is no need to install a transformer or a current transformer for extracting frequency and phase information of power supplied to a power facility, and a partial discharge detection device that is easy to install in an already installed power facility. The purpose is to provide.

1 is a block diagram showing the configuration of an embodiment of a partial discharge detection apparatus according to the present invention;

2 is a timing chart showing the operation of the partial discharge detection apparatus according to the present invention;

3 is a block diagram showing a configuration of an embodiment of a partial discharge detection device according to the present invention;

4 is a block diagram showing a configuration of an embodiment of a partial discharge detection device according to the present invention;

5 is a block diagram showing a configuration of an embodiment of a partial discharge detection device according to the present invention;

6 is a block diagram showing a configuration of an embodiment of a partial discharge detection device according to the present invention;

7 is a block diagram showing a configuration example of a conventional partial discharge detection device.

* Description of the symbols for the main parts of the drawings *

1 antenna (means for detection) 2 high frequency amplifier (means for detection)

3: Peak value detection circuit (means for detecting peak values)

4: Comparator (1st comparator) 4a: Comparator (2nd comparator)

5: signal processing unit (means for determining) 11, 11a, 11b: band filter

12, 12a: Low pass filter 15, 15a: PLL

16, 16a: converter 17: high-stable oscillator

As shown in FIG. 2A, the voltage of the electric power supplied to the electric power equipment changes into a sine wave shape, and partial discharge occurs after the voltage rises to some extent in the sine wave, as shown in FIG. 2B. Therefore, there is a synchronous relationship between the partial discharge and the electric power flowing to the electric power facility (if it is not synchronized, it is considered disturbance), and the partial discharge includes a frequency component of electric power supplied to the electric power facility to some extent. If the frequency information (50 Hz, 60 Hz) and phase information are extracted and used to determine the synchronous state such as the frequency matching state between the partial discharge and the power flowing through the power equipment and the repetition frequency or repetition frequency of the same phase difference, a transformer And the same effect as before can be expected without providing a current transformer.

The partial discharge detection apparatus according to the first invention includes means for detecting an electrical signal resulting from a partial discharge generated in a power facility, means for detecting a peak value of an electrical signal detected by the means, and a peak value detected by the means. Compares the first predetermined value with the first predetermined value to detect a synchronous state between the first comparator for outputting a signal when the peak value is greater than the first predetermined value, and the power supplied to the power equipment and the signal output by the first comparator. A signal generation circuit for creating and outputting a signal to be generated based on the signal output from the first comparator, and a synchronous state detected by detecting the synchronous state of the signal output from the first comparator and the signal comparator, respectively. On the basis of this, it is characterized by comprising means for determining that the partial discharge has occurred.

In the partial discharge detection device according to the second aspect of the present invention, the signal generation circuit includes a band pass filter for passing a frequency component of power supplied to a power equipment included in a signal output by the first comparator, and a frequency component passed through the band filter. A second comparator which compares the amplitude of the signal with a second predetermined value and outputs a signal when the amplitude of the frequency component is greater than the second predetermined value, and a signal for detecting a synchronization state of the signal output by the second comparator Characterized in that made to be.

In the partial discharge detection device according to the third aspect of the present invention, the signal generation circuit includes a low pass filter for passing a frequency component of power supplied to a power equipment included in a signal output by the first comparator, and a frequency component passed by the low pass filter. It is characterized in that it has a PLL operating based on the above, and the signal output by the PLL is a signal for detecting a synchronization state.

In the partial discharge detection device according to the fourth aspect of the present invention, a band pass filter includes two band pass filters each passing two commercial frequency components, and a switch for switching the two band pass filters, and a band of the one to which the switch switches. The frequency component passed through the filter is configured to be supplied to the second comparator.

In the partial discharge detection device according to the fifth aspect of the present invention, the PLL has two voltage controlled oscillators for oscillating two commercial frequency signals, and a switch for switching the two voltage controlled oscillators, The voltage controlled oscillator may be configured to output the oscillated frequency signal.

The partial discharge detection apparatus according to the sixth invention includes means for detecting an electrical signal resulting from partial discharge generated in a power facility, means for detecting a peak value of an electrical signal detected by the means, and a peak value detected by the means. Compares a predetermined value with a predetermined value, and outputs a signal when the peak value is larger than the predetermined value, and generates and outputs a signal for detecting a synchronization state between the power supplied to the power equipment and the signal output by the comparator. And an oscillator, means for detecting the synchronous state of the comparator and the signals output by the oscillator, and determining that the partial discharge has occurred, based on the detected synchronous state.

Hereinafter, the present invention will be described with reference to the drawings showing the embodiments.

(Example 1)

1 is a block diagram showing the configuration of Embodiment 1 of a partial discharge detection apparatus according to the present invention. This partial discharge detection device is one of an antenna 1 (means for detecting) that detects an electromagnetic wave caused by partial discharge generated by insulation deterioration in a power facility, and an electric signal due to the electromagnetic wave detected by the antenna 1. With the high frequency amplifier 2 (means for detecting) which amplify to an easy level, and the diode 3a and the condenser 3b which are means for detecting the peak value (peak value) of the electric signal which the high frequency amplifier 2 amplified. The peak detection circuit 3 (or quasi-peak detection circuit) which consists of these is provided. As an alternative to the antenna 1, a high frequency current transformer for detecting a current flowing through the main circuit of the power equipment in accordance with partial discharge may be used.

The partial discharge detection device further compares the peak value detected by the peak value detection circuit 3 with a predetermined value (first predetermined value), and outputs a signal when the peak value is larger than the predetermined value ( First comparator), a band pass filter 11 for passing frequency components of power supplied to the power equipment included in the signal output by the comparator 4, and amplitude and frequency of the frequency components passed by the band pass filter 11; A comparator 4a (second comparator) for comparing a value (second predetermined value) and outputting a signal when the amplitude of the frequency component is larger than the predetermined value is provided.

The partial discharge detection device is also a signal processing unit which is means for detecting a synchronous state of signals output by the comparator 4 and the comparator 4a, respectively, and determining that partial discharge has occurred in the power equipment according to the detected synchronous state. (5) and an alarm generator (6) which is means for outputting an alarm by the determination of the signal processor (5).

The high frequency amplifier 2, the peak value detection circuit 3, the comparator 4, the band pass filter 11, the comparator 4a, the signal processing part 5, and the alarm generation part 6 mentioned above are partial discharge signal processing. Configure the device 10a.

The operation of the partial discharge detection device having such a configuration will be described below with reference to the timing chart of FIG. 2.

If insulation deterioration occurs in the power equipment, partial discharge occurs in a portion where insulation deterioration occurs. The current flowing by this partial discharge becomes an impulsive current. The antenna 1 detects electromagnetic waves generated by this impulsive current. When a high frequency current transformer is used instead of the antenna 1, current flowing through the main circuit of the power equipment is detected in accordance with partial discharge.

The high frequency amplifier 2 amplifies the electric signal b by the electromagnetic wave detected by the antenna 1 to a level that is easy to process. The peak value detection circuit 3 detects the peak value of the electric signal b amplified by the high frequency amplifier 2 (c) and supplies it to the comparator 4. The comparator 4 compares the supplied peak value with a predetermined value and outputs a signal when the peak value is larger than the predetermined value (d).

The band pass filter 11 passes the frequency component of the power a flowing through the power equipment included in the signal output by the comparator 4, and the comparator 4a passes the frequency component e that the band filter 11 passes. Is compared with a predetermined value, and a signal is output when the amplitude of the frequency component is larger than the predetermined value (f).

The center frequency of the band pass filter 11 can be arbitrarily selected as long as it is an integer multiple of the power source frequency.

The signal processing unit 5 is a repetition frequency or repetition frequency of the same phase difference and a state in which the frequency of the signal output from the comparator 4 and the comparator 4a and the phase match the frequency of the partial discharge and the power supplied to the power equipment, respectively. Etc., a synchronous state is detected, and it is determined whether partial discharge generate | occur | produced based on the detected synchronous state. The alarm generating unit 6 outputs an alarm when the signal processing unit 5 determines the occurrence of partial discharge.

As mentioned above, the partial discharge detection apparatus which does not need to install the transformer or the current transformer for extracting the frequency and phase information of the electric power which flows through an electric power installation can be implemented.

(Example 2)

3 is a block diagram showing the configuration of Embodiment 2 of a partial discharge detection apparatus according to the present invention. The partial discharge detection device includes a low pass filter 12 and a low pass filter for removing the noise component of the high frequency 4 included in the signal output by the comparator 4 to pass the frequency component of power flowing through the power equipment. PLL15 (Phase Locked Loop) which operates based on the frequency component passed by 12). The low pass filter 12 and the PLL 15 are configured as narrowband filters.

The PLL 15 has a phase comparator 13, a low pass filter 12a, and a voltage controlled oscillator 14, and the phase comparator 13 is used to output each output signal of the low pass filter 12 and the voltage controlled oscillator 14. The frequency and phase are compared, and a voltage proportional to the difference is output. This voltage is averaged by the low pass filter 12a and supplied to the voltage controlled oscillator 14. The voltage controlled oscillator 14 is controlled so that the phase difference between the output signal and the output signal of the low pass filter 12 is minimized and output as the output signal of the PLL 15. In addition, the PLL 15 may be configured by a digital circuit.

This partial discharge detection device is also a means for detecting the synchronous state of the signals output by the comparator 4 and the PLL 15, respectively, and determining that partial discharge has occurred in the power equipment based on the detected synchronous state. The signal processing part 5 and the alarm generation part 6 which are means for outputting an alarm by the determination of the signal processing part 5 are provided.

The comparator 4, the low pass filter 12, the PLL 15, the signal processing section 5, and the alarm generating section 6 described above are the high frequency amplifier 2 and the peak value detection circuit 3 already described in the first embodiment. And a partial discharge signal processing device 10b. Since the other structure is the same as the structure of the partial discharge detection apparatus of Example 1 mentioned above, description is abbreviate | omitted.

The operation of the conventional partial discharge detection device having such a configuration will be described below.

The comparator 4 compares the supplied peak value with a predetermined value and outputs a signal when the peak value is larger than the predetermined value.

The low pass filter 12 removes the high frequency noise component included in the signal output by the comparator 4 and passes the frequency component of the power supplied to the power equipment, so that the PLL 15 receives the low pass filter 12. Operates in accordance with the frequency component passed by, outputs a signal having the same frequency and phase as the output signal of the low pass filter 12.

The signal processing unit 5, from the frequency and phase of the signal output from the comparator 4 and the PLL 15, respectively, the frequency of coincidence between the partial discharge and the power supplied to the power equipment and the number of repetitions or repetitions of the same phase difference. A synchronous state such as a frequency is detected, and it is determined whether partial discharge has occurred or not based on the detected synchronous state. The alarm generating unit 6 outputs an alarm when the signal processing unit 5 determines the occurrence of partial discharge. Other operations are the same as those of the partial discharge detection apparatus of the first embodiment described above, and thus description thereof is omitted.

As mentioned above, the partial discharge detection apparatus which does not need to install the transformer or the current transformer for extracting the frequency and phase information of the electric power which flows through an electric power installation can be implemented.

(Example 3)

4 is a block diagram showing the configuration of Embodiment 3 of a partial discharge detection apparatus according to the present invention. This partial discharge detection device is included in the bandpass filter 11a which passes a frequency component of 50 Hz of the electric power supplied to the electric power equipment contained in the signal output by the comparator 4, and the signal output by the comparator 4; A band pass filter 11b for passing a frequency component of 60 Hz of power supplied to an electric power facility to be supplied, a switch 16 for changing the output of each of the band filters 11a, 11b, and a band filter on the side changed by the switch 16 Comparator 4b (second comparator) for comparing the amplitude of the frequency component passed by 11a and 11b with a predetermined value (second predetermined value) and outputting a signal when the amplitude of the frequency component is larger than the predetermined value. do.

The partial discharge detection device further detects the synchronous state of the signals output by the comparator 4 and the comparator 4b, respectively, and is a signal that is means for determining that partial discharge has occurred in the power equipment based on the detected synchronous state. A processing unit 5 and an alarm generating unit 6 which is means for outputting an alarm by the determination of the signal processing unit 5 are provided.

The comparator 4, the band filters 11a and 11b, the switch 16, the signal processor 5 and the alarm generator 6 described above are the high frequency amplifier 2 and the peak value detection circuit described in the first embodiment. Together with (3), the partial discharge signal processing apparatus 10c is configured. Since the other structure is the same as the structure of the partial discharge detection apparatus of Example 1 mentioned above, description is abbreviate | omitted.

The operation of the conventional partial discharge detection device having such a configuration will be described below.

The converter 16 is previously switched to either one of the bandpass filters 11a and 11b in accordance with the frequency 50 Hz or 60 Hz of the power supplied to the electric power equipment.

The comparator 4 compares a given peak value with a predetermined value and outputs a signal when the peak value is larger than the predetermined value.

The bandpass filter 11a or the bandpass filter 11b previously changed by the converter 16 passes a frequency component of 50 Hz or 60 Hz included in the signal output by the comparator 4. In addition, the center frequency of the band pass filters 11a and 11b may be an integer multiple of 50 Hz or 60 Hz.

The comparator 4b compares the amplitude of the frequency component of 50 Hz or 60 Hz output by the band filter 11a or the band filter 11b with a predetermined value, and outputs a signal when the amplitude of the frequency component is larger than the predetermined value.

The signal processing unit 5, from the frequency and phase of the signal output by the comparator 4 and the comparator 4b, respectively, is the coincidence state of the frequency of the power supplied to the partial discharge and the power equipment and the repetition frequency or repetition frequency of the same phase difference. Etc., the synchronous state is detected, and it is determined whether partial discharge has occurred or not based on the detected synchronous state. The alarm generating unit 6 outputs an alarm when the signal processing unit 5 determines the occurrence of partial discharge. Other operations are the same as those of the partial discharge detection apparatus of the first embodiment described above, and thus description thereof is omitted.

From the above, there is no need to provide a transformer or a current transformer for extracting frequency and phase information of electric power supplied to the electric power equipment, and the partial discharge detection device can be used either at a frequency of 50 Hz or 60 Hz of electric power supplied to the electric power equipment. Can be realized.

(Example 4)

Fig. 5 is a block diagram showing the construction of Embodiment 4 of the partial discharge detection apparatus according to the present invention. The partial discharge detection device includes a low pass filter 12 and a low pass filter 12 which remove high frequency noise components included in the signal output by the comparator 4 and pass frequency components of power supplied to the power equipment. PLL 15a (Phase Locked Loop), which operates on the basis of the frequency component passed by it, is provided. The low pass filter 12 and the PLL 15a constitute a narrow band filter.

The PLL 15a is a feedback closed circuit having a phase comparator 13, a low pass filter 12a, a voltage controlled oscillator 14a at 50 Hz, a voltage controlled oscillator 14b at 60 Hz, and a switch 16a, and a phase comparator 13 ) Compares the frequency and phase of each output signal of either the low-pass filter 12 and the voltage controlled oscillators 14a and 14b switched by the switch 16a, and outputs a voltage proportional to the difference. This voltage is averaged by the low pass filter 12a and supplied to the voltage controlled oscillators 14a and 14b. Either of the voltage controlled oscillators 14a and 14b switched by the switch 16a is controlled so that the phase difference between the output signal and the output signal of the low pass filter 12 is minimized and is used as the output signal of the PLL 15a. Is output.

The partial discharge detection device further detects the synchronous state of the signals output by the comparator 4 and the PLL 15a, respectively, and is a signal which is means for determining that partial discharge has occurred in the power equipment based on the detected synchronous state. A processing unit 5 and an alarm generating unit 6 which is means for outputting an alarm by the determination of the signal processing unit 5 are provided.

The comparator 4, the low pass filter 12, the PLL 15a, the signal processing section 5, and the alarm generating section 6 described above are the high frequency amplifier 2 and the peak value detection circuit 3 described in the first embodiment. And the partial discharge signal processing apparatus 10d. Since the other structure is the same as the structure of the partial discharge detection apparatus of Example 1 mentioned above, description is abbreviate | omitted.

The operation of the conventional partial discharge detection device having such a configuration will be described below.

The switch 16a is previously switched to the voltage controlled oscillator 14a or the voltage controlled oscillator 14b in accordance with the frequency 50 Hz or 60 Hz of the power supplied to the electric power equipment.

The comparator 4 compares the supplied peak value with a predetermined value and outputs a signal when the peak value is larger than the predetermined value.

The low pass filter 12 removes the high frequency noise component included in the signal output by the comparator 4, and passes the frequency component of the power flowing through the power equipment, so that the PLL 15a receives the low pass filter 12. Operation is performed based on the frequency component passed through, and outputs a signal having the same frequency (50 Hz or 60 Hz) and phase as the output signal of the low pass filter 12.

The signal processing unit 5, from the frequency and phase of the signal output from the comparator 4 and the PLL 15a, respectively, is the frequency of coincidence between the partial discharge and the power supplied to the power equipment and the number of times or repetition of the same phase difference. A synchronous state such as a frequency is detected, and it is determined whether partial discharge has occurred or not based on the detected synchronous state. The alarm generating unit 6 outputs an alarm when the signal processing unit 5 determines the occurrence of partial discharge. Other operations are the same as those of the partial discharge detection apparatus of the first embodiment described above, and thus description thereof is omitted.

From the above, there is no need to provide a transformer or a current transformer for extracting frequency and phase information of power flowing through the power equipment, and a partial discharge detection device that can be used either at a frequency of 50 Hz or 60 Hz of power flowing through the power equipment. Can be realized.

(Example 5)

Fig. 6 is a block diagram showing the construction of Embodiment 5 of the partial discharge detection apparatus according to the present invention. This partial discharge detection device has a high oscillation oscillator having the same frequency as the center frequency of the power supplied to the power equipment for detecting the synchronous state between the power supplied to the power equipment and the signal output by the comparator 4. (17) and a signal processing unit which is a means for detecting a synchronous state of signals output from the comparator 4 and the high oscillator 17, respectively, and determining that partial discharge has occurred in the power equipment based on the detected synchronous state. (5) and an alarm generator (6) which is means for outputting an alarm by the determination of the signal processor (5).

The comparator 4, the high oscillator 17, the signal processor 5, and the alarm generator 6 described above are part together with the high frequency amplifier 2 and the peak value detection circuit 3 already described in the first embodiment. The discharge signal processing apparatus 10e is configured. Since the other structure is the same as the structure of the partial discharge detection apparatus of Example 1 mentioned above, description is abbreviate | omitted.

The operation of the conventional partial discharge detection device having such a configuration will be described below.

The comparator 4 compares the supplied peak value with a predetermined value and outputs a signal when the peak value is larger than the predetermined value.

The high-stable oscillator 17 outputs having the same center frequency as the frequency of the power supplied to the power equipment for detecting the synchronous state between the power supplied to the power equipment and the signal output by the comparator 4.

The signal processing unit 5 is the frequency of the signal output from the comparator 4 and the high oscillator 17, and the phase, respectively, the frequency of coincidence between the partial discharge and the power supplied to the power equipment and the number of repetitions of the same phase difference. Or a synchronous state, such as a repetition frequency, is detected, and it is determined whether partial discharge generate | occur | produced based on the detected synchronous state. The alarm generating unit 6 outputs an alarm when the signal processing unit 5 determines the occurrence of partial discharge. Other operations are the same as those of the partial discharge detection apparatus of the first embodiment described above, and thus description thereof is omitted.

As mentioned above, the partial discharge detection apparatus which does not need to install the transformer or the current transformer for extracting the frequency and phase information of the electric power which flows through an electric power installation can be implemented.

In the partial discharge detection apparatus according to the first invention, the means for detecting detects an electrical signal in accordance with the partial discharge generated in the power equipment. The means for detecting the peak value detects the peak value of the detected electrical signal. The first comparator compares the detected peak value with the first predetermined value and outputs a signal when the peak value is larger than the first predetermined value. The signal generating circuit generates and outputs a signal for detecting a synchronous state between the power supplied to the electric power equipment and the signal output by the first comparator based on the signal output by the first comparator.

The means for determining detects the synchronous state of the signals output by the first comparator and the signal generating circuit, respectively, and determines that partial discharge has occurred based on the detected synchronous state. As a result, it is not necessary to provide a transformer or a current transformer for extracting frequency and phase information of power supplied to the power equipment, and a partial discharge detection device that can be easily installed in an already installed power equipment can be realized.

In the partial discharge detection device according to the second invention, the band pass filter of the signal generating circuit passes a frequency component of power supplied to the power equipment included in the signal output by the first comparator. The second comparator of the signal generating circuit compares the amplitude of the frequency component passed by the band pass filter with the second predetermined value and outputs a signal when the amplitude of the frequency component is larger than the second predetermined value. The output signal is used as a signal for detecting a synchronous state. As a result, it is not necessary to provide a transformer or a current transformer for extracting frequency and phase information of power supplied to the power equipment, and a partial discharge detection device that can be easily installed in an already installed power equipment can be realized.

In the partial discharge detection device according to the third aspect of the present invention, a low pass filter of a signal generating circuit passes a frequency component of power flowing through a power equipment included in a signal output by a first comparator, and a PLL (Phase Locked Loop) It operates based on the frequency component passed, and uses the signal output by the PLL as a signal for detecting the synchronization state. As a result, it is not necessary to provide a transformer or a current transformer for extracting frequency and phase information of power supplied to the power equipment, and a partial discharge detection device that can be easily installed in an already installed power equipment can be realized.

In the partial discharge detection device according to the fourth aspect of the invention, two band filters, which are band filters, respectively pass two commercial frequency components, so that the switch of the band filter switches the two band filters. The frequency component passed by the bandpass filter on the side changed by the converter is supplied to the second comparator. As a result, it is not necessary to provide a transformer or a current transformer for extracting frequency and phase information of power flowing through the power equipment, and can cope with any of the commercial frequencies of 50 Hz or 60 Hz of the power supplied to the power equipment. It is possible to realize a partial discharge detection device that is easy to install in the installed power equipment.

In the partial discharge detection device according to the fifth aspect of the invention, two voltage controlled oscillators of the PLL oscillate two commercial frequency signals, respectively, and the converter switches the two voltage controlled oscillators. The PLL outputs a frequency signal oscillated by the voltage-controlled oscillator on the side of the switch. Accordingly, it is not necessary to install a transformer or a current transformer for extracting frequency and phase information of power supplied to the power equipment, and can cope with any of commercial frequencies 50 Hz or 60 Hz of power supplied to the power equipment. It is possible to realize a partial discharge detection device that is easy to install in an already installed power facility.

In the partial discharge detection apparatus according to the sixth invention, the means for detecting detects an electrical signal due to the partial discharge generated in the power equipment. The means for detecting the peak value detects the peak value of the detected electrical signal. The comparator compares the detected peak value with a predetermined value and outputs a signal when the peak value is larger than the predetermined value.

The oscillator oscillates and outputs a signal for detecting a synchronous state between the power supplied to the electric power equipment and the signal output by the comparator.

The determining means detects the synchronous state of the signals output by the comparator and the oscillator, respectively, and determines that partial discharge has occurred based on the detected synchronous state. As a result, it is not necessary to install a transformer or a current transformer for extracting frequency and phase information of power supplied to the power equipment, thereby realizing a partial discharge detection device that is easy to install in an already installed power equipment.

Claims (3)

Means for detecting an electrical signal resulting from the partial discharge generated in the electric power plant, means for detecting the peak value of the electrical signal detected by the means, and comparing the peak value detected by the means with the first predetermined value to determine the peak value. The first comparator outputs a first comparator that outputs a signal when the value is greater than the first predetermined value, and a signal for detecting a synchronous state between the power supplied to the power equipment and the signal output by the first comparator. A signal generating circuit to create and output based on a signal, the first comparator and a signal output by the signal comparator, respectively, detects a synchronous state, and determines that the partial discharge has occurred based on the detected synchronous state. The partial discharge detection apparatus characterized by the above-mentioned. The method of claim 1, The signal generating circuit compares a band pass filter for passing a frequency component of power supplied to a power equipment included in a signal output by the first comparator, and an amplitude and a second predetermined value of the frequency component passed by the band filter. And a second comparator for outputting a signal when the amplitude of the frequency component is greater than a second predetermined value, wherein the signal output by the second comparator is configured to be a signal for detecting a synchronous state. Device. A means for detecting an electrical signal resulting from the partial discharge generated in the power equipment, a means for detecting the peak value of the electrical signal detected by the means, and comparing the detected peak value with a predetermined value to determine a peak value. A comparator for outputting a signal when the value is greater than the value, an oscillator for oscillating and outputting a signal for detecting a synchronization state between the power supplied to the power equipment and the signal output by the comparator, and the comparator and the oscillator are respectively output And a means for detecting a synchronous state of one signal and determining that the partial discharge has occurred based on the detected synchronous state.