Device for detecting partial discharges

FIELD: electricity.

SUBSTANCE: device for detecting partial discharges comprises high-voltage direct-current power supply source with high-voltage capacitor connected to it through one position of switch key; through the second position of switch key the tested facility is connected with a sensor connected to the facility. Oscilloscope is coupled to the sensor through a shielded wire. Direct-current power supply source, capacitor and sensor are interconnected at common point and grounded. The technical effect is as follows: device for detecting partial discharges allows diagnosing direct-current machines.

EFFECT: potential detection of partial discharge signals in insulation of direct-current motors.

1 dwg

 

The invention relates to the field of measurement of electrical quantities and can be used to detect signals of partial discharges in electrical insulation of DC motors in the diagnosis of defects of isolation.

A device for measuring partial discharges [RU 2402092 C1, IPC NN 9/50 (2006.01), publ. 20.10.2010], contains located inside the electrostatic screen and having a common grounding a partial discharge sensor, made in the form of inductors, analog-to-digital and optical converters and a common power supply converters. The input of analog-to-digital Converter connected with potential output inductors and the output of which is connected to the input of the optical Converter, the output of which is connected an optical cable connected to an external measuring device. The device comprises an amplifier with a negative gain and is supplied with a signal and Pogranichnaya windings disposed on an electrostatic screen. The signal winding is connected to the input of the amplifier, the output of which is connected Pogranichnaya winding. The elements listed above have a common ground potential.

A device for the continuous monitoring of partial discharges in the insulation of high-voltage three-phase conditions in�the rd operation, comprising at least one active portion in the form of electrically conductive interconnected elements under high voltage and is surrounded by layers of insulation [RU 2393494 C1, IPC G01R 31/02 (2006.01), publ. 27.06.2010]. In addition, this device contains circuitry processing, registration of partial discharge signal and at least one sensor-signal receiver of partial discharges, which is used as the active part of a three-phase high-voltage apparatus. Measuring PD signals produced simultaneously on all three phases of HV apparatus at a common point of the active part of the device with use of low-voltage measuring voltage transformers, connected according to the scheme broken Delta.

A device for controlling characteristics of partial discharges [RU 2019850 C1, MPK G01R 31/12, publ. 15.09.1994], selected as a prototype containing the test transformer, high voltage capacitor, series-connected high-pass filter, measurement cable and instrument recording. One of the capacitor plates is live lived of the test object, which is parallel to the conductive plate, the second plate of the capacitor connected to the input of the high pass filter, made in the form of a segment �whoprovides line with distributed parameters. The capacitance CChigh-voltage capacitor and the impedance of the RHK measuring cable made coaxial, satisfy

where Tand- pulse duration partial discharge.

The evaluation unit includes series-connected integrating broadband amplifier, comparator, pulse counter and indicator.

The total lack of analogues is that these devices diagnosis of partial discharges are working on AC current. For DC machines, such devices are not acceptable.

The object of the invention is to provide a device for detecting partial discharges, allowing to diagnose DC machine.

The task is solved due to the fact that the device for detecting partial discharges as well as in the prototype contains a high voltage capacitor and a logger.

According to the invention parallel to high-voltage power source of direct current high voltage capacitor connected across one of the provisions of the switching key, via another position of which is connected to the capacitor test subject that is connected to the sensor, the recording device used oscilloscope that using shielded wire�d is associated with the sensor, and the source of DC power, a capacitor and the sensor are connected in common and grounded.

Thus, through the use of a power capacitor as a source of pulsed DC voltage, the proposed device allows to detect partial discharges in windings of DC motors that will identify insulation defects at the initial stage of their occurrence.

Fig.1 schematically shows the inventive device.

Device for detecting partial discharge contains a high voltage power supply constant current 1, in parallel to which is connected a high-voltage capacitor 2 via one of the provisions of patch 3 key. Through another switching position of the key 3 to the capacitor 2 connected to the test object 4 (IO), which is connected to the sensor 5 (E), through which the shielded wire is connected with the oscilloscope 6 (Oh). The DC power supply 1, the condenser 2 and sensor 5 (D) are connected in common and grounded.

As the sensor 5 (E) used in a low-inductance resistor.

The proposed device operates as follows. For charging the high-voltage capacitor 2 is used, the power source 1. Charged capacitor 2 switch switching key 3 from the power source 1 to the subject object 4 (IO), e.g.� to the winding section of a DC motor. Upon discharge, the capacitor 2 outputs a pulse DC voltage, which passes through the test object 4 (IO). If the voltage is sufficient, appear partial discharges, which fix the sensor 5 (D) and record the oscilloscope 6 (O), which allows to represent the data in graphs or tables for further processing. Grounding serves as protection from electric shock.

Device for detecting partial discharges containing high-voltage capacitor and the evaluation unit, characterized in that parallel to high-voltage power source of direct current high voltage capacitor connected across one of the provisions of the switching key, via another position of which is connected to the capacitor test subject that is connected to the sensor, the recording device used oscilloscope, through which the shielded wire is connected with the sensor, and the source of DC power, a capacitor and the sensor are connected in common and grounded.



 

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