RU210358U1 - Connection filter with coupling capacitor leakage current sensor - Google Patents

Abstract

The utility model relates to high-frequency communication over wires of power lines used in the field of energy. The connection filter with a leakage current sensor of the coupling capacitor consists of a drain coil 4, one terminal 3 of which is made with the possibility of electrical connection with the coupling capacitor 2. The second terminal 5 of the drain coil 4 is intended for connection to the ground 7. It contains a leakage current sensor, which is represented by an indicator of electromagnetic fields in the form of an inductor 6 with an air core. The second output 5 of the drain coil 4 passes through the electromagnetic field indicator, forming a series circuit, and is grounded. An electromagnetic field indicator in the form of an inductor 6 with an air core and a drain coil 4 are placed inside a housing 9 made of a dielectric material and are fixed relative to each other with a gap preferably at a distance of 1-50 mm. The electromagnetic field indicator is placed along the longitudinal axis of the electromagnetic field of the second output 5 of the drainage coil 4. The output 8 of the electromagnetic field indicator is made with the possibility of electrical connection with a measuring device, for example, an analog signal input module. The electromagnetic field indicator is tuned to resonance with the frequency of the industrial current in the electrical network. EFFECT: high operational reliability for a long time. 3 w.p. f-ly, 2 ill.

Description

The utility model relates to high-frequency communication over wires of power lines used in the field of energy.

The connection filter (FP) is designed to connect the equipment of high-frequency channels of relay protection, emergency automation, telephone communication and data transmission to the phase wires of overhead power lines with a voltage of 35-750 kV. The connection filter, together with the coupling capacitor, represents a transformer (autotransformer) band-pass filter circuit. Each filter modification is designed to operate in a specific frequency band and with a specific coupling capacitor or capacitive voltage transformer.

The use of a coupling capacitor connected to a high-voltage power line carries certain risks of a technical, economic nature, and may also threaten the life and health of service personnel, due to the possibility of insulation breakdown with a subsequent explosion of such a coupling capacitor. As a result of such an explosion, damage to the property of the substation, fire, operation of protections on the connected and other lines, shutdown of the communication channel itself can occur, in addition, fragments can cause severe injury to maintenance personnel, including death. Thus, the task of early detection of degradation of the insulation of the coupling capacitor is relevant in order to prevent emergency situations.

A known system for monitoring the state of coupling capacitors (patent for invention RU2675250 dated March 22, 2018), including at least one coupling capacitor connected to the power line and a connection filter, additionally contains a controller and at least one sensor for monitoring the coupling capacitor, moreover, the number of sensors corresponds to the number of capacitors, the coupling capacitor is connected in series with the coupling capacitor control sensor, to which the inlet filter pin is connected in series, and the output terminals of the coupling capacitor control sensor are connected to the analog input of the controller by means of a connecting cable.

A coupling capacitor control sensor is known (patent for invention RU 2675248 dated 03/22/2018), including input and output connectors, a transformer, the primary winding of which is connected through the input connector to the gap between the lower lining of the coupling capacitor and the connection filter, a diode bridge to which the outputs are connected secondary winding of the transformer, the first resistor and two capacitors connected in parallel and connected to the terminals of the diode bridge, the second and third resistors that form the output current, one of which is a tuning resistor, the second terminals of which are connected to the output connector contacts.

The disadvantages include the need to adapt existing connection filters to connect sensors for monitoring the coupling capacitor.

A filter is known for connecting high-frequency communication channels to high-voltage lines (utility model patent RU 6485 dated April 10, 1997), consisting of an autotransformer, one of the winding terminals of which is connected to a coupling capacitor, and the other is grounded, the autotransformer together with the coupling capacitor form an L-shaped bandpass filter, the bandwidth of which is determined by the capacitance of the capacitor and the inductance of the autotransformer.

The disadvantages include the lack of means to control the capacitance of the coupling capacitor, and, as a result, a high accident rate at power facilities due to the complete destruction of the coupling capacitors as a result of breakdown of its elements.

The closest to the proposed solution are the connection filter with an integrated sensor for monitoring the coupling capacitor (patent for invention No. RU 2713161 dated July 11, 2019), consisting of a transformer, one of the winding terminals of which is connected to the coupling capacitor, and the other is grounded, the transformer is equipped with an additional a separate winding to which a coupling capacitor control sensor is connected.

The disadvantages include a complex execution scheme, as well as a possible impact on the characteristics of the connection filter due to the additional winding of the transformer, which can lead to the inoperability of the communication channel, as well as the need to adapt the existing connection filters to connect sensors for monitoring the coupling capacitor. The technical task is to create a connection filter that provides high operational reliability for a long time.

The technical task is to create a connection filter that provides high operational reliability for a long time.

EFFECT: high operational reliability for a long time.

High operational reliability is achieved by providing the ability to control the coupling capacitor without affecting the characteristics of the connection filter, while eliminating the influence of mechanical and electrical factors on its operation.

The problem is solved by the fact that the inventive connection filter, consisting of a drain coil placed in a housing made of a dielectric material, with a leakage current sensor of the coupling capacitor, one output of the drain coil is made with the possibility of electrical connection with the coupling capacitor, the other output is grounded. The leakage current sensor is represented by a direct wire current indicator in the form of an air-core inductor, installed inside the housing on the drain coil wire connected to the ground, and its outputs are made with the possibility of electrical connection with the measuring device.

A feature of the proposed design is that inside the housing of the proposed connection filter, a leakage current sensor is fixed on the earth wire of the drain coil, which is an indicator of the direct conductor current, designed for the industrial frequency of the current in the electrical network, and does not affect the settings of the filter itself, the frequency of which starts from 16 kHz.

The inventive attachment filter differs from the prototype in the following features:

contains a direct wire current sensor as a leakage current sensor of the coupling capacitor;

the current indicator is made in the form of an air-core inductor;

the current indicator is located on the earth wire of the connection filter drain coil;

the drain coil and the current indicator in the form of an air-core inductor are housed in a housing made of a dielectric material;

the outputs of the current indicator are made with the possibility of electrical connection with the measuring device.

The presence of the above distinguishing features allows us to conclude that the claimed utility model meets the criterion of "novelty".

As a drain coil, for example, industrially produced from air-type PETV-1.2 wire, it can be used, it is designed for the passage of industrial frequency current without loss and, together with the coupling capacitor, is tuned by inductance to the frequency range of the connection filter.

As a dielectric material for the manufacture of the housing and auxiliary fasteners (angles), for example, fiberglass or similar materials known for these purposes can be used. The use of a dielectric material eliminates the possibility of mechanical damage, the effects of moisture and air on the normal operation of the connection filter, and prevents distortion of the readings of the leakage current sensor of the coupling capacitor.

As a current indicator, made in the form of an air-core inductor, commercially available coils from a winding wire with an inductance of several Gn can be used to be able to operate on industrial frequency current.

As a measuring device, for example, the ENMV-3 analog signal input module with a sensitive analog input can be used.
with measurement range -75…0…+75 mV.

The claimed device can be manufactured by known methods from known elements using known materials, which allows us to conclude that the claimed utility model meets the criterion of "industrial applicability".

The inventive connection filter with a coupling capacitor leakage current sensor is illustrated by the following illustrations.

In FIG. 1 shows a circuit diagram of the connection filter with a leakage current sensor of the coupling capacitor represented by a current indicator in the form of an air-core inductor.

In FIG. 2 schematically shows the design of the inventive connection filter with a coupling capacitor leakage current sensor.

On the presented diagrams explaining the claimed design, the following symbols are adopted:

where 1 is the input from the power line

2 - coupling capacitor

3 - drain coil of the connection filter

4 - output from the drain coil to the coupling capacitor

5 - output from the drain coil to the ground

6 - current indicator in the form of an air-core inductor

7 - earth

8 - current indicator output to the measuring device

9 - rear wall of the connection filter housing

10 - elbows for fastening the drain coil and the electromagnetic field indicator in the form of an inductor with an air core

11 - bolts for fastening to the body

12 - terminal block

The inventive connection filter consists of a drain coil 4, fixed inside the housing 9, made of fiberglass, on its rear wall through the angles 10, made of fiberglass, electrically connected, on the one hand, through the first output 3 with the coupling capacitor 2. On the other hand, the drainage coil 4 contains a second output 5, intended for connection with ground 7. Inside the housing 9 there is a leakage current sensor, which is a current indicator in the form of an inductor 6 with an air core. The inductor 6 with an air core is fixed through the angles 10 on the back wall of the housing 9 by means of fasteners in the form of bolts 11 along the longitudinal axis of the electromagnetic field created by the second output 5 of the drain coil 4. The drain coil 4 and the inductor with an air core 6 are fixed inside the housing 9 , while the second output 5 of the drain coil 4 passes through the air-core inductor 6 to the terminal block 12 and is connected to ground 7. The terminal block 12 is also attached to the rear wall of the housing 9 with bolts 11. The output 8 of the air-core inductor 6 is connected to measuring device (not shown). The measuring device measures the current strength and can be represented, for example, by an analog signal input module with a sensitive analog input ENMV-3 with a measurement range of -75…0…+75 mV.

The inventive attachment filter works as follows.

When a power frequency current flows through the drain coil 4, due to the reactance of the coupling capacitor 2, around the second output 5 of the drain coil 4 to the ground 7, electromagnetic induction occurs in accordance with Faraday's law. An electromagnetic field of industrial frequency current arises around the second terminal 5, and when the second terminal 5 is placed inside the inductor 6 with an air core, an alternating voltage of the industrial frequency arises, which is measured in the measuring device at the output 8. According to the measured alternating voltage from the inductor 6 s the air core, which acts as a leakage current sensor, determines the leakage current of the coupling capacitor 2, and it is also possible to judge the increase in the capacitance of the coupling capacitor 2 and its going beyond the established limits.

The claimed device makes it possible to achieve the claimed technical result due to:

measuring the leakage current of the coupling capacitor on the drain coil of the connection filter is carried out in a non-contact way, that is, it does not require a change in the design of the connection filter, and the effect on the characteristics (attenuation of inconsistency, operating attenuation) of the connection filter itself is minimized;

the use of a small number of circuit elements, as a result of which the reliability of its operation increases;

no need to use precision reference elements for current measurement.

The inventive connection filter with a coupling capacitor leakage current sensor provides the ability to control the coupling capacitor without affecting the characteristics of the connection filter by measuring the current in the wire connected to ground and the absence of interference in the design of the drain coil, as well as the absence of galvanic coupling, mechanical and electrical isolation from the influence external factors on the drain coil and the leakage current sensor of the coupling capacitor, which leads to high operational reliability of the connection filter for a long time.

Claims (4)

1. Connection filter with a leakage current sensor of the coupling capacitor, consisting of a drain coil, one terminal of which is configured to be electrically connected to the coupling capacitor, characterized in that the leakage current sensor is represented by an electromagnetic field indicator in the form of an air-core inductor, while the second the output of the drain coil passes through the electromagnetic field indicator and is grounded, the electromagnetic field indicator and the drain coil are placed inside a housing made of a dielectric material and are fixed relative to each other with a gap, the electromagnetic field indicator is located along the longitudinal axis of the electromagnetic field of the second output of the drain coil, and the output electromagnetic field indicator is made with the possibility of electrical connection with the measuring device. 2. The filter according to claim 1, characterized in that the gap between the drain coil and the electromagnetic field indicator is 1-50 mm. 3. The filter according to claim 1, characterized in that the electromagnetic field indicator is tuned to resonance with the frequency of the industrial current in the electrical network. 4. Filter according to claim 1, characterized in that the measuring device is represented by an analog signal input module.

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