JPH0381674A - Partial discharge detector for electric apparatus - Google Patents

Abstract

PURPOSE:To surely detect a partial discharge generated in a winding without an effect of noise by making the constitution so as to detect the partial discharge generated in the winding in accordance with the detecting conditions of a magnetic sensor and UV receiving sensor. CONSTITUTION:When the partial discharge is generated in the winding 2 during the operation of a main body 1 for transformer, an electromagnetic wave occurred according to the discharge is emitted. Then, magnetic field components of electromagnetic wave according to the partial discharge are concentrated to a magnetic core 6 of the magnetic sensor 5; therefore, a voltage signal V1 in accordance with the intensity variation of magnetic field components which are concentrated to the magnetic core 6 is outputted to a discharge detecting circuit 10 from the sensor 5 through an amplifier 7. On the other hand, when the discharge is generated in the winding 2, a light is generated in accordance with that discharge, so the UV rays accompanying the discharge are received by the UV receiving sensor 8. A light receiving signal V2 in accordance with the received light is thereby outputted to the discharge detecting circuit 10 from the sensor 8 through an amplifier 9. Then, signals Pa for abnormality are outputted to an abnormality display device 11 by the circuit 10 when these signal levels are beyond a set level.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a partial discharge detection device for electrical equipment that detects partial discharge generated in a winding.

(Prior Art) For example, in a transformer filled with sulfur hexafluoride gas (SFs), an organic polymer material such as polyethylene terephthalate may be used as an insulating material for the winding. In the case of windings insulated with such organic polymer materials, there is a risk that partial discharge will occur in the windings and the insulation performance will deteriorate. consideration is given to In addition, similar partial discharge problems occur in transformers treated with epoxy resin or the like, and in windings of rotating electric machines, etc., so consideration must be given to the design.

However, partial discharge may occur in the windings due to long-term operation, and in such cases, it is desirable to take immediate action. Therefore, as a device for detecting partial discharge occurring in the winding, it has been considered to use a device that detects electromagnetic waves generated due to partial discharge. That is, this device detects the occurrence of partial discharge by detecting electromagnetic waves generated due to partial discharge with an electromagnetic sensor placed near the winding.

(Problems to be Solved by the Invention) However, in the conventional configuration, when noise electromagnetic waves enter an AC voltage converter, for example, the magnetic sensor may detect the noise electromagnetic waves. Therefore, based on the fact that the magnetic sensor enters the detection state even though no partial discharge has occurred in the winding, there is a possibility that it may be mistakenly recognized that partial discharge has occurred in the winding.

The present invention has been made in view of the above circumstances, and its object is to provide partial discharge #1 for electrical equipment that can reliably detect partial discharge occurring in the winding without being affected by noise.
To provide a detection device.

[Structure of the Invention] (Means for Solving the Problems) The present invention detects the magnetic field component of electromagnetic waves generated in the vicinity of the winding of an electrical device due to partial discharge of the winding, and outputs an electric signal. In addition to arranging a magnetic sensor that detects ultraviolet rays among the weak light emitted from the winding, an ultraviolet light receiving sensor that specifically detects only ultraviolet rays is provided, and based on electrical signals from both of these, partial discharge generated in the winding is detected. A discharge detection circuit is provided for detection.

(Function) When a partial discharge occurs in the winding of an electrical device, electromagnetic waves accompanying the partial discharge are discharged from the winding and reach the magnetic sensor. Then, a voltage signal corresponding to the magnetic field component of the interlinked electromagnetic waves is output from the magnetic sensor to the discharge detection circuit. Here, when partial discharge occurs in the winding, weak light accompanying the discharge is emitted from the winding. This light consists of a visible light part (wavelength range of 4° to 700 am) and an ultraviolet part (wavelength of 400 am or less). Among this ultraviolet light in the 8M range, those with wavelengths of 300 am or less are shorter than the wavelengths of ultraviolet light contained in sunlight, electric lamps, and other light. Therefore,
If the discharge light is detected using an ultraviolet light receiving sensor that detects light of 300 m1 or less as the light when a partial discharge occurs, the light will be detected according to the occurrence of the discharge regardless of external light (this is considered as noise). Output a signal. Thereby, the discharge detection circuit correctly determines that partial discharge has occurred in the winding based on the electric signal from the magnetic sensor and the signal from the ultraviolet light receiving sensor.

On the other hand, when a noise electromagnetic wave interlinks with the magnetic sensor, the noise electromagnetic wave becomes 1? An electrical signal is given from the magnetic sensor to the discharge detection circuit. However, if no partial discharge has occurred in the wire, the light (ultraviolet rays) accompanying the h'1 electric current from the winding
Since no light is emitted, no light reception signal is output from the ultraviolet photoelectric sensor. As a result, the discharge offfi detection circuit determines that no partial discharge has occurred in the winding even if it receives an electrical signal from the magnetic sensor.

(Example) Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

In FIG. 1 showing the overall configuration, 1 is a transformer main body, which is made up of a winding 2 insulated with, for example, polyethylene terephthalate, wound around an iron core 3, and filled with sulfur hexafluoride gas (SF6). It is stored in a tank 4. Note that the tank 4 is formed of a shielding member that has shielding properties against electromagnetic waves.

A magnetic sensor 5 and an ultraviolet light receiving sensor 8 are provided near the winding 2 of the transformer body 1. The magnetic sensor 5 is formed by winding a plurality of conducting wires around a rod-shaped magnetic core 6, for example, and outputs a voltage signal V1 to an amplifier 7 in response to changes in the magnetic field interlinking with the magnetic core 6. On the other hand, the ultraviolet light receiving sensor 8 outputs a light receiving signal (2) to the amplifier 9 according to the light receiving level. The voltage signal V amplified by this amplification rM7
1 and the light reception signal v2 amplified by the amplifier 9 are guided to the discharge detection circuit 10, where their signal levels are measured,
11-1 When each of the fixed signals exceeds a set level, an abnormality signal Pa is output to the abnormality display device 11. The abnormality display device 11 displays that partial discharge has occurred in the winding when the abnormality signal Pa is manually input.

Next, the operation of the above configuration will be explained.

During operation of the transformer main body 1, part 1jk electric current may be generated in the winding 2, and in such a case, electromagnetic waves are emitted from the winding 2 due to the discharge. Then, since the magnetic field component of the electromagnetic wave accompanying the partial discharge is concentrated on the magnetic core 6 of the magnetic sensor 5, a voltage signal v1 corresponding to the intensity change of the magnetic field component concentrated on the magnetic core 6 is output from the magnetic sensor 5 via the amplifier 7. and is output to the discharge detection circuit 10.

On the other hand, when a discharge occurs in the winding 2, light is generated along with the discharge, so the ultraviolet light receiving sensor 8 receives the ultraviolet light accompanying the discharge. As a result, the ultraviolet light receiving sensor 8 outputs a light receiving signal v2 corresponding to the received light to the discharge detecting circuit 10 via the amplifier 9.

The discharge detection circuit 10 receives a voltage signal v1 from the magnetic sensor 5.
and the signal level of the light reception signal v2 from the ultraviolet light reception sensor 8 is measured, and when these signal levels exceed the set level, the abnormality signal Pa is sent to the abnormality display device 11.
Output to. As a result, the abnormality display device 11 indicates that a partial discharge has occurred in the winding 2, so by checking the display, it is possible to recognize that a partial discharge has occurred in the winding 2 of the transformer body 1. I can do it.

However, when noise electromagnetic waves with a large signal level enter the tank 4, which is designed to block the passage of electromagnetic waves, or when noise electromagnetic waves are emitted from the power transmission line route, the noise electromagnetic waves are chained to the magnetic sensor 5. A voltage signal v1 higher than the set level may be output. however,
In such a case, the discharge detection circuit 10 will not erroneously detect that a partial discharge has occurred in the winding 2. That is, when no partial discharge occurs in the winding 2, no ultraviolet light accompanying the partial discharge is emitted from the winding 2, so the ultraviolet light receiving sensor 8 does not output a light receiving signal v2 higher than the set level. As a result, the discharge detection circuit 10 detects that even if the voltage signal v1 higher than the set level is manually input from the magnetic sensor 5, the light reception signal 2 higher than the set level is not input from the ultraviolet light receiving sensor 8. Based on this, the abnormality signal Pa is not output to the abnormality display device 11.

Therefore, since the occurrence of partial discharge is not displayed on the abnormality display device 11, there is no possibility of erroneously recognizing that a partial hk discharge has occurred in the winding 2.

In addition, if a partial discharge occurs in the winding 2 and light enters from the outside in a good condition, the ultraviolet light receiving sensor 8 will only be sensitive to the overhead ultraviolet light (wavelength 400 am or less) generated by the partial discharge. Therefore, voltage No. 13 v2 is not output for light such as sunlight (incandescent light) or electric light that contains almost no light of this wavelength. Further, the magnetic sensor itself does not output the equivalent output signal v1. Therefore, the discharge detection circuit 10
In this case, it is not determined that a partial discharge has occurred in the @ line 2.

In short, according to the above embodiment, the occurrence of partial discharge in the winding 2 is determined based on the light reception state of the ultraviolet light receiving sensor 8 in addition to the detection state of the magnetic sensor 5. Unlike the conventional example in which the occurrence of partial discharge is detected only by a sensor, the winding 2 is equipped with a partial molecule 11.
It is possible to reliably detect the occurrence of electricity.

In the above embodiment, the application was applied to detecting partial discharge occurring in the winding of a gas insulated transformer, but instead, it can be applied to electrical equipment such as an oil-immersed transformer, a molded transformer, or a rotating machine or an axle. The portion 8 generated in this case may be applied to the detection of electricity. Furthermore, a Hall element or a magnetoresistive element may be used as the magnetic sensor.

[Effects of the Invention] As is clear from the above description, the partial discharge detection device for electrical equipment of the present invention detects partial discharges occurring in the windings based on the detection states of the bi1 gas sensor and the ultraviolet light receiving sensor. Since the configuration is configured to detect the partial discharge, it is possible to reliably detect the partial discharge generated in the winding without being affected by noise, which is a great practical effect.

[Brief explanation of drawings]

FIG. 1 is an overall configuration diagram showing one embodiment of the present invention. In the figure, l is the transformer body, 2 is the winding, 5 is the magnetic sensor, 8
1 is an ultraviolet light receiving sensor, and 10 is a discharge detection circuit.

Claims (1)

[Claims] A magnetic sensor is placed near the winding of an electrical device and outputs an electrical signal by detecting the magnetic field component of electromagnetic waves generated due to partial discharge in the winding, and detects ultraviolet rays emitted along with the electromagnetic waves from the winding. an ultraviolet light receiving sensor that outputs a received light signal; and a discharge detection circuit that detects partial discharge generated in the winding based on electrical signals from the magnetic sensor and the ultraviolet light receiving sensor. Equipment partial discharge detection device.