SU1366973A1 - Device for checking leakage current in autonomous electric power supply systems - Google Patents

Abstract

The invention can be used in devices for real-time consumer detection with reduced insulation resistance. The purpose of the invention is to improve the accuracy and electrical safety control. The device contains Hall sensors (HF) 1 and 2, the differential amplifier 7; DC voltage source 3 and indicator 8. The introduction of an alternating current source 6 of increased frequency (1-3 kHz), measuring unit 5, section 4 of the reference cable allows power supply HF 1 and 2 from source 6 non-. belt current increased frequency. In this case, DC 1 and 2 are equally located with respect to the external magnetic field and do not have a galvanic connection with the test object. 2 Il. S

Description

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The invention relates to instrumentation technology and can be used in devices for the rapid detection of consumers with reduced insulation resistance in autonomous power supply systems with insulated neutral,

The aim of the invention is to improve the accuracy and electrical safety while monitoring by powering the Hall sensors from an alternating current source of increased frequency, of the same position relative to the external magnetic field in the absence of galvanic communication with the test object.

Fig. 1 shows the electrical circuit of the device proposed; Fig, 2 - constructive execution of the device,

The device for monitoring leakage current in autonomous power supply systems (Fig. 1) contains the first 1 and second 2 Hall sensors with counter-connected Hall circuits, a DC voltage source 3, a reference cable section 4, a measuring unit 5, an AC source 6 a higher frequency current (1-3 kHz), differential amplifier 7, indicator 8, First 1 and second 2 Hall sensors are connected in series on the power supply, the first input of the differential amplifier 7 is connected to the first output of the first Hall sensor 1; the first and second outputs of the amplifier 7 are connected to the corresponding inputs of the indicator 8; the second input of the amplifier 7 is connected to the first output of the second Hall sensor 2; a DC voltage source 3 is connected to a series-connected measuring unit 5 and a length 4 reference cable; The first and second outputs of an alternating current source 6 of increased frequency are connected to the inputs of the first 1 and second 2, respectively, Hall sensors, whose transverse axes of symmetry coincide.

In addition, Hall sensors 1 and 2 are fixed in a housing (Fig. 2) with two saddles 9 and 10, which is located in the middle of segment 4 of the reference cable. The latter is attached to the holder 11 with a handle 12. Case with sensors 1 and 2 with the first saddle

9 tight to the .4 segment of the reference cable.

The operation of the device is based on measuring the current flowing through it, through a cable connecting the masses of the source of electricity and the consumer,.

The device works as follows

A source of operational DC voltage (not shown) is connected to the controlled AC buses of the 1I power source to its mass, thereby creating

together with cables connecting the masses of the electricity source to consumers, closed circuits for leakage currents through the insulation resistance of consumers. If, for one reason or another, a decrease in the insulation resistance of the corresponding consumer occurs, this causes an increase in the total leakage current of the power supply system, which is detected

with a suitable device, measure the total leakage current,

In this case, the operator applies the device to the second saddle.

10 to one of the cables connecting the masses of the source of electrical energy and the corresponding consumer, and it does this without disconnecting consumers from the source of electrical supply, i.e., without interrupting the supply of electrical consumers. The length 4 of the reference cable is arranged parallel to the cable connecting the mass of the source of electrical energy and the corresponding consumer, and the second saddle 10 covers the specified cable. Next, change the voltage source 3, achieve a zero reading on the indicator 8, which corresponds to the equality

voltage with the output of sensors 1 and 2. In this case, the current in section 4 of the reference cable is equal in magnitude to the leakage current of the corresponding consumer, and the magnetic fields indicated

Cables in the locations of the device are equal and equally oriented. Next, using the measuring unit 5 (depending on the values in which the scale is calibrated), either the leakage current is determined or

insulation resistance of the corresponding consumer.

A similar leakage current measurement is carried out in all other cables.

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connecting the mass of the source of electrical energy with the masses of the respective consumers until a consumer with increased leakage current (with low insulation resistance) is detected, i.e. The consumer at the moment is in an emergency condition.

The invention improves the accuracy of leakage current monitoring, allows you to quickly find a consumer with a reduced insulation resistance without disconnecting the power supply network from consumers, as a result of which labor costs are reduced when a failure is detected. Electrical safety is also increased in the control process due to the absence of galvanic communication between the device and the control object.

Claims (1)

Invention Formula A device for monitoring leakage current in autonomous power supply systems, containing the first and second Hall sensors connected in series along power lines to Editor A. Makovska Compiled by E. Berezov Tehred L. Serdyukova ten 66973 countercoupled Hall circuits, pi, DC voltage source, differential amplifier, the first input of which is connected to the first output of the first Hall sensor, and the first and second outputs to the corresponding indicator inputs, which in order to improve the accuracy and electrical safety, an alternating current source of the spun frequency, a measuring unit, a segment of the reference cable are inserted into the device, the DC voltage source being connected to serially connected measuring blocks com cable and the segment reference, the first and second outputs of the high frequency alternating current source are connected respectively to corresponding inputs of the first and second Hall effect sensors, the second input differential amplifier, a unified 15 20 with the first output of the second sensor 25 Hall, and the Hall sensors are placed in the plane of the longitudinal axis of the segment of the reference cable so that their transverse axes of symmetry coincide. 2 Proofreader A. T sko