RU195641U1 - Device for monitoring the state of insulation of a high voltage input - Google Patents

Abstract

The utility model relates to the electric power industry and can be used to monitor the insulation state of high-voltage electrical inputs, equipped for this purpose with a measuring output. EFFECT: increased reliability and safety of a device for monitoring the state of insulation of a high voltage input. Essence: the conductive housing of the device is made with the possibility of its installation on the measuring output of the high voltage input (10). The housing is equipped with an electrical connector (4) for external connection. A grounding element (6) is fixed in the housing in the form of a bolt screwed into a threaded hole with the possibility of electrical contact with the pin of the measuring output, and an inductor (5) is placed. The coil (5) is placed with the possibility of transformation of the current flowing through the measuring output, and is connected to the contacts of the electrical connector (4). The housing of the device can be made of one part or of two parts (1) and (2) having a threaded connection (3), which is sealed with sealant and shunted by a conductive jumper (13). In the process of monitoring insulation under operating voltage, the measurement output of the high-voltage input directly through the device casing is closed to the casing of the high-voltage input. 2 s.p. f-ly, 3 ill.

Description

Technical field

The utility model relates to the electric power industry and can be used to monitor the insulation state of high-voltage electrical inputs, equipped for this purpose with a measuring output.

Currently, a large number of high-voltage bushings are used in operation, which are accessories of transformers, reactors and tank oil circuit breakers.

The test lead, for attachment to which the claimed device is intended, is an insulated pin electrically connected to the last (grounded) lining of the capacitor high voltage input, while the pin is removed through the side pipe of the high voltage input, which serves as the housing of the measuring output. Under normal operating conditions (i.e., under operating voltage), the test lead must be earthed to prevent breakdown of the insulation of the high voltage input. For this purpose, the specified side pipe (housing of the test terminal) is provided with an external thread, onto which a protective cap with a contact element is screwed, which provides electrical contact of the test terminal with the metal casing of the high-voltage input. One of the possible designs of the measuring output of the high voltage input is described, for example, in patent RU 138399.

State of the art

The insulation condition of the high voltage input is monitored by measuring the leakage current flowing through the measuring output to the grounded casing of the high voltage input. Devices for monitoring the state of insulation are fixed on the test lead instead of the standard (factory) grounding cap in order to enable the measurement of the indicated leakage current.

A device is known - an analogue containing a node for protection against surge surges at a high-voltage input, a node for protection against overvoltages caused by an open circuit of the ground current, and a current transformer, the primary winding of which is connected in parallel to these protection nodes between the measuring terminal and the ground terminal, i.e. in dissection of the ground circuit of the measuring output [RU78327]. The secondary winding of the current transformer is designed to be connected to a current-measuring device.

Known devices of the brand DB-2, manufactured in a wide range by DIMRIS, a description and photos of which are available at https://dimrus.ru/db2.html. According to the description, “in the DB-2 device there are no transformations of the controlled input parameters, but only additional protection elements for the measuring output of the controlled input are installed in all special input operation modes; this has to be done because the DB-2 devices are installed in place of the protective caps that close the measuring input terminal to the ground. " Thus, in these devices, the protection nodes and the current-measuring circuit parallel to them, connected via an electrical connector, are included in the cut-out of the ground circuit of the measurement terminal.

The disadvantage of both analogues, which manifests itself when monitoring the state of the input insulation under the operating voltage, is the increased likelihood of an open ground circuit of the test lead grounding circuit, since the standard (i.e., provided by the manufacturer of high-voltage bushings) ground circuit of the test lead is broken and additional elements are introduced into it - protection nodes and an input circuit of a current-measuring device connected via a connector.

As a prototype, the design of the DB-2 device was selected.

Utility Model Essence

The technical result of the utility model is to increase the reliability and safety of the device for monitoring the state of insulation of the high voltage input, due to the fact that during the monitoring of insulation under the operating voltage, the measurement output of the high voltage input directly through the device’s case (and not through an external current-measuring circuit, as in analogs) is closed to the casing high-voltage input, and, as a result, simplification of the device (eliminates the need for nodes of protection against surge surges and from overvoltages caused by ar tion circuit measuring the output ground).

The subject of a utility model is a device for monitoring the state of insulation of a high-voltage input, comprising a conductive housing configured to be installed on the measurement terminal of a high-voltage input and provided with an electrical connector for external connection, characterized in that a ground element is provided in the housing for electrical connection with a stud measuring output, and the inductor is placed with the possibility of transforming into it a leakage current flowing through itelny conclusion, the inductor is connected to the contacts of the electric connector.

The development of the utility model is that:

- the housing of the device can be made of one part or two parts having a threaded connection;

- the threaded connection of two parts of the housing can be sealed with a sealant and shunted by a conductive jumper.

- the grounding element can be made, for example, in the form of a bolt screwed into the threaded hole of the housing with the possibility of electrical contact with the pin of the measuring output or in the form of a flexible conductive bridge, one end of which is fixed in the housing and the other on the pin of the measuring input.

The execution of the housing of the device from one part simplifies the design and manufacturing technology of the device, and the execution of the housing from two parts reduces the requirements for the dimensions of the inductor.

Short list of figures

In FIG. 1, as an example, presents the inventive device mounted on the measuring output of a high voltage input, the housing of which is made of two parts, and the grounding element is in the form of a bolt. FIG. 2 illustrates the assembly process of the device shown in FIG. 1. FIG. 3 illustrates the implementation of the device in a housing of one part with a grounding element in the form of a flexible conductive jumper. The implementation of the utility model, taking into account its development.

In the figures indicated:

1 and 2 - the first and second parts of the conductive housing of the device, respectively;

3 - threaded connection of parts 1 and 2 of the housing (Fig. 2);

4 - electrical connector, mounted in part 2 of the housing, designed for external connection to a current-measuring circuit, i.e. the input circuit of the means for monitoring the insulation state of the high voltage input;

5 - inductor, the findings of which are connected to the contacts of the connector 4;

6 - grounding element, in the form of a metal bolt, the rod of which is screwed when assembling the device into the threaded hole 7 of part 2 of the housing.

In addition, the figures show: a high-voltage input 10, a pin 8 of the measuring output and its body 9 (which is a side input pipe 10) having an external thread 11 for a standard (factory) grounding cap, in place of which the inventive device is installed.

Part 1 of the housing has an internal thread 12 for screwing onto the thread 11.

When assembling the device, the terminals of the coil 5 are connected by flexible conductors to the contacts of the connector 4, which is equipped with part 2 of the housing. Then the coil 5 is placed inside the housing part 2 and the housing parts 1 and 2 are connected using a threaded connection 3. In this case, to prevent atmospheric moisture from entering the device’s body, the threaded connection 3 is sealed with a sealant (for example, silicone or polyurethane), which is applied to the turns threads before connecting parts 1 and 2 of the housing. To ensure reliable electrical contact of the sealed parts 1 and 2 of the housing, the sealed threaded connection 3 is bridged with a flexible conductive jumper 13, the ends of which are attached to the connected parts 1 and 2 of the housing (for example, using screws).

The assembled housing (with coil 5) is mounted on the measurement terminal, providing its electrical connection with the casing of the high voltage input. To do this, screw the thread 12 onto the thread 11 of the housing 9 of the measuring output, providing reliable electrical contact of the device casing with a metal casing of the input 10.

Then, a bolt 6 is screwed into the threaded hole 7. The rod of the bolt 6 is passed through the central hole of the coil 5 and pressed to the pin 8 of the measuring output. In this case, the bolt 6 closes the ground circuit of the measuring output, providing electrical connection of the stud 8 with the input casing 10 through the housing of the device, and the coil 5 covers the shaft of the bolt 6 and / or the pin of the output 8.

The grounding element can be made as shown in FIG. 3, in the form of a flexible conductive jumper 14, one end of which is fixed to the housing from one part 15 (for example, using a screw 16 screwed into the housing from the inside), and the other on a stud 8 (for example, using a nut 17 screwed onto hairpin 8).

In FIG. 3 also shows a possible installation of the housing of the claimed device on the input casing 10 using a bolted connection that provides electrical contact between the housing and the casing.

The device operates as follows.

When monitoring the insulation state of the input 10 under the operating voltage, the leakage current of the insulation flows from the last lining of the capacitor insulation of the input 10 through the pin 8 of the measuring output connected to it and the ground circuit including the grounding element (bolt 6 in Fig. 1 or jumper 14 in Fig. 3) and the device casing (or its parts 1 and 2 connected by a jumper 13) installed to ensure electrical contact with the metal casing of the input 10. Thus, the inventive device closes the ground circuit of the measuring output.

Coil 5 covers at least one of the elements of the above-described ground circuit located in the housing of the device (pin 8, element 6). As a result, the leakage current, transforming into the coil 5, induces a secondary current in it, which through the connector 4 and the connecting cable (not shown in the figures) enters the current measuring circuit of the means that controls the insulation state of input 10. The parameters of the measured current (magnitude, frequency, phase ) are completely determined by the leakage current of the insulation of the input 10 flowing through the pin 8 of the measuring output, which does not impose any restrictions on the method of monitoring the state of insulation.

As can be seen from the above, due to the fact that the grounding element 6 is fixed in the housing of the inventive device, intended for electrical connection with the measuring output (its pin 8), and placed with the possibility of transformation of the current flowing through the measuring output, the inductor 5 connected to the contacts electrical connector 4, the ground circuit of the measuring output, formed when using the inventive device, in fact, repeats the factory ground circuit when using the standard protection deleterious cap. In this case, it is not necessary to introduce a current-measuring circuit (including the input circuit of the current-measuring device and the wires leading to it) into the open circuit of the measurement output ground circuit.

This increases the reliability and safety of the device by reducing the risk of an open circuit ground, and allows to simplify the device, because there is no need to protect the measuring output from surge surges and overvoltages caused by an open ground circuit.

Claims (3)

1. A device for monitoring the state of insulation of a high-voltage input, comprising a conductive housing configured to be installed on the measuring output of a high-voltage input and equipped with an electrical connector for external connection, characterized in that the ground element is fixed in the housing in the form of a bolt screwed into a threaded hole with the possibility of electrical contact with the pin of the measuring output, and an inductance coil is placed with the possibility of transforming into it a leakage current flowing through the pin of the measuring output, while the inductor is connected to the contacts of the electrical connector. 2. The device according to claim 1, in which the housing is made of one part or of two parts having a threaded connection. 3. The device according to claim 2, in which the threaded connection is sealed with a sealant and shunted by a conductive jumper.

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