RU209674U1 - 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 3, one terminal of which is made with the possibility of electrical connection with the coupling capacitor 2, and the second terminal is grounded 4. As a leakage current sensor, it contains an electromagnetic field indicator in the form of an inductor 5 with a core, placed along the longitudinal axis 8 of the electromagnetic field of the drain coil 3. The drain coil 3 and the electromagnetic field indicator are placed in 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 output 7 of the electromagnetic field indicator is designed to be electrically connected to a measuring device, preferably an analog signal input module. The electromagnetic field indicator in the form of an inductor 5 with a core is tuned to resonance with the frequency of the industrial current in the electrical network. EFFECT: high operational reliability of the connection filter for a long time. 4 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 coupling capacitor insulation is relevant in order to prevent emergency situations.

A known system for monitoring the state of coupling capacitors (patent for invention RU 2675250 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 input filter pin is connected in series, and the output terminals of the coupling capacitor control sensor are connected to the controller analog input via 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 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 separate winding to which the 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.

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 filter connection with a leakage current sensor of the coupling capacitor, consisting of a drain coil placed in a housing made of a dielectric material, one output of the drain coil is made with the possibility of electrical connection with the coupling capacitor, and the second output is grounded, while contains an electromagnetic field indicator in the form of an inductor with a core as a leakage current sensor, fixed inside the housing with a gap relative to the drain coil and oriented along the longitudinal axis of the electromagnetic field of the drain coil, the output of the electromagnetic field indicator is made with the possibility of electrical connection with the measuring device.

The leakage current sensor of the coupling capacitor, represented by an indicator of the electromagnetic field of industrial frequency, made in the form of an inductor with a core, can additionally be equipped with a tuning capacitor, forming a parallel circuit of the leakage current sensor.

A feature of the proposed design is that inside the housing of the proposed connection filter near the drainage coil along the longitudinal axis of its electromagnetic field, a leakage current sensor is fixed with a gap, which is an indicator of the electromagnetic field. The electromagnetic field indicator is made in the form of an inductor with a core, which, by itself or together with a tuning capacitor, is tuned to resonance with the frequency of the industrial current in the electrical network and does not affect the settings of the filter itself, the frequency of which starts from 16 kHz.

The term with a gap relative to the drain coil means the placement of the electromagnetic field indicator at a distance of 1-50 mm.

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

contains an electromagnetic field indicator as a leakage current sensor;

the electromagnetic field indicator is made in the form of an inductor with a core;

an electromagnetic field indicator in the form of an inductor with a core is placed along the longitudinal axis of the electromagnetic field of the drainage coil,

the drain coil and the indicator of the electromagnetic field in the form of an inductor with a core placed in a housing made of a dielectric material;

the drain coil and the electromagnetic field indicator in the form of an inductor with a core are fixed relative to each other with a gap;

the output of the electromagnetic field indicator is 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 an indicator of the electromagnetic field in the form of an inductor with a core, industrially produced coils made of PETV wire with an inductance of several Gn can be used to enable operation at industrial frequency current.

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

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 in the embodiment with an electromagnetic field indicator in the form of an inductor with a core and a tuning capacitor.

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:

1 - input from the power line;

2 - coupling capacitor;

3 - drain coil of the connection filter;

4 - earth;

5 - leakage current sensor, represented by an electromagnetic field indicator in the form of an inductor with a core;

6 - tuning capacitor;

7 - output of the leakage current sensor to the measuring device (not shown);

8 - axis of the electromagnetic field of the drainage coil;

9 - rear wall of the connection filter housing;

10 - elbows made of a dielectric material for fastening a drain coil and an inductor with a core;

11 - fasteners in the form of bolts for attaching the squares to the body;

12 - conclusions of the drainage coil for connection with the coupling capacitor;

13 - outputs of the drain coil for connection to the ground.

The inventive connection filter consists of a drainage coil 3 fixed inside the housing 9, made of fiberglass, on its rear wall, connected, on the one hand, through terminals 12 with a coupling capacitor 2, and on the other hand, through terminals 13 with ground 4, as well as a current sensor leakage, which is an indicator of the electromagnetic field, made in the form of an inductor 5 with a core, as well as an optional tuning capacitor 6. The inductor 5 with a core is fixed inside the housing 9 on its rear wall along the longitudinal axis 8 of the electromagnetic field of the drainage coil 3 with a gap 1 -50 mm, and the outputs 7 of the leakage current sensor, made in the form of an inductor 5 with a core, are connected to a measuring device (not shown) that measures the current strength, which can be represented, for example, by an analog signal input module with a sensitive analog input ENMV- 3 with measurement range -75…0…+75 mV. The drain coil 3 and the inductor 5 with a core are fixed on the rear wall of the housing 9 by means of angle bars 10 made of a dielectric material and fasteners 11 in the form of bolts. The inductor 5 with a core, together with the tuning capacitor 6, is tuned to resonance with the frequency of the industrial current in the electrical network.

The inventive attachment filter works as follows.

When a power frequency current flows through the drain coil 3, due to the reactance of the coupling capacitor 2, electromagnetic induction occurs around the drain coil 3 in accordance with Faraday's law. When the current sensor is located in the form of an inductor 5 with a core along the axis 8 of the electromagnetic field of the drain coil 3, an alternating voltage occurs in the inductor 5 with a core, which is measured in the measuring device at the output 7 of the inductor 5 with a core. According to the measured alternating voltage from the inductor 5 with a core, which acts as a leakage current sensor, the leakage current of the coupling capacitor 2 is determined, 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 (5)

1. Connection filter with a leakage current sensor of the coupling capacitor, consisting of a drain coil, one terminal of which is made with the possibility of electrical connection with the coupling capacitor, and the second terminal is grounded, characterized in that, as a leakage current sensor, it contains an electromagnetic field indicator in the form of an inductor with a core, located along the longitudinal axis of the electromagnetic field of the drainage coil, the drainage coil and the electromagnetic field indicator are placed in a housing made of a dielectric material, fixed relative to each other with a gap, the output of the 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 additionally contains a tuning capacitor, forming a parallel circuit with a core inductor. 4. The filter according to claim 1, characterized in that the electromagnetic field indicator in the form of an inductor with a core is tuned to resonance with the frequency of the industrial current in the electrical network. 5. Filter according to claim 1, characterized in that the measuring device is represented by an analog signal input module.

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