RU2762208C1 - Method for remote diagnostics of time intervals between contacts and drive operation during switching of three-phase switches in operating electrical networks - Google Patents

Abstract

FIELD: switches voltage measuring.

SUBSTANCE: invention relates to measuring the parameters of high-voltage and low-voltage three-phase switches in operating electrical networks, in particular, the determination of the difference in timing of closing and opening of contacts, as well as the time intervals of the drive. In front of the switches at an isolation voltage distance, a group of three magnetic antennas in the form of inductance coils is placed, axes directed perpendicular to the terminals of three phases A, B, C of a three-phase switch, each in a U-shaped metal screen. The outputs of the magnetic antennas are connected to three inputs of a multichannel analog-to-digital converter, the output of which is connected to a computer. On the screen of the latter, visually, by the type of voltage oscillograms, the nature of the change in the strengths of the magnetic fields of each of the phases during the switching of the contacts is determined, according to which the time intervals between the values of the variable parameters of the processes of opening or closing the contacts of each phase are determined. Then, opposite the mechanical moving elements of the switch drive, a motion sensor is installed, the output of which is connected to an additional input of a multichannel analog-to-digital converter connected to a computer. On the computer screen, the movements of the moving elements of the drive are recorded, the time intervals between the initial and final values of the drive operation and the corresponding characteristic points during the switching of contacts are determined. With the combined consideration of the time intervals between the contacts and the time intervals of the drive, the full-time cycle is determined when switching three-phase switches with their subsequent comparison with the normalized values.

EFFECT: improving performance, increasing the accuracy of processing the results of measuring the timing of contacts, as well as the operation of the drive when switching three-phase switches.

1 cl, 6 dwg

Description

The invention relates to the electric power industry for non-contact diagnostic monitoring of the time intervals between contacts, the operating time of the drive, through parallel channels of high-voltage and low-voltage three-phase switches, in particular, the timing of the closing and opening of the contacts of the switches, in combination with the time intervals of the drive installed in the existing electrical networks.

The invention is intended for measuring the parameters of switches in operating electrical networks in order to timely remove the switches from the electrical network for repairs upon detection of faults in their contact system and the operation of the drive, exceeding the normalized parameters regulated by RD 34.45-51.300-97. "Scope and norms of testing electrical equipment", "Operating instructions for circuit breakers", as well as during commissioning tests.

A device is known for determining the timing of the closure of movable contacts of switches with fixed contacts based on a simple circuit with incandescent lamps published in the "Collection of methodological manuals for monitoring the state of electrical equipment" (section 4 "Methods for monitoring the state of switching devices"), M, ORGRES, 1997, With. 52.

The device contains a constant voltage source and three lamps connected in series in the circuit of each phase of the contact system of the high-voltage switch. In this device, the difference in timing of the closure of movable contacts with fixed contacts is carried out indirectly by the difference in linear displacements of movable contacts in different phases in the switch chamber without oil and is carried out slowly by manually closing the switch using a lever or a jack. The fixation of the contact of the contacts in each phase is carried out by the operator by lighting up the corresponding lamps and gradually marking the positions of the guide tube on the insulating rod with a pencil. Then the ruler manually measures the positions of the moving contacts.

The measurement accuracy in the given device depends to a large extent on subjective factors. The device is not automated and it technically lacks the ability to determine the time of switching on and off the switch, as well as to identify contact bounce.

There is also known a method for remote diagnostics of the time intervals of contacts of three-phase switches in operating electrical networks, characterized in that a magnetic antenna in the form of an inductance coil is installed in front of the switches at an isolation distance in voltage, with an axis directed perpendicularly to the terminals of a three-phase switch, in which the operating operating currents of the phases create the magnetic intensity fields and magnetic flux, connect the output of the magnetic antenna to the input of an analog-to-digital converter of a digital oscilloscope, the output of the latter is connected to a computer, on which, using a special program, the voltage changes proportional to the currents of the electrical network are visualized in the form of oscillograms, and pulse harmonic processes are emitted when switching the switch contacts , according to the maximum values of which the time intervals of the divergence of the switch contacts are recorded. This method is described in RF Patent No. 2745808, MKP G01R 31/333 (2006.01). Method for remote diagnostics of time intervals of contacts of three-phase switches in operating electrical networks / V.M. Saltykov, A.V. Saltykov, A.V. Saltykov. Registered. in the state. register 04/01/2021. Bul. No. 10.

This method is the closest to the claimed in technical essence and is taken as a prototype. However, it has the following disadvantages:

when using a single magnetic antenna for three-phase electrical networks with switches, the total magnetic field strength from three-phase currents is induced in it, which, when superimposed, pulse-harmonic transient processes during switching contacts, characteristic of high-voltage three-phase switches, makes it possible to estimate the time intervals of contact divergence, as a rule , only by maximum values and does not allow considering transient processes in phases independently of each other when switching contacts.

The technical result of the proposed method is to improve the performance and increase the accuracy of processing the results of measuring the time intervals of contacts, the operating time of the drive, when switching three-phase switches in existing electrical networks to monitor the state of their operability in real time.

In the proposed method, the principle of remote diagnostics is used, since the state of the switches is monitored in operating electrical networks, that is, without turning them off.

The technical result is achieved by the fact that in the method of remote diagnostics of time intervals of contacts of three-phase switches in operating electrical networks when switching contacts of three-phase switches, currents of three phases A; V; WITH; create pulse-harmonic transient processes in the surrounding space in the cross-sectional plane of conductors of three phases A; V; WITH; according to Ampere's law, magnetic field strengths arise, which are perceived by magnetic antennas with U-shaped metal screens to protect against magnetic fields of adjacent phases, represented by three turn inductor coils, the axes of which are perpendicular to the phase conductors. The antennas are installed on a tripod or on the walls of the cubicles of complete switchgears (KRU), and their outputs are connected to three inputs of a multichannel analog-to-digital converter (ADC), which in turn is connected to a computer, which allows using a special program on the general computer screen to visually in the form of oscillograms, determine the nature of the change in the strengths of the magnetic fields of each of the phases, represented by the voltage values, with the selected initial or maximum moments of individual parallel pulse-transient processes for each of the three switched contacts of the switch, according to which the time intervals between the single-valued values of the variable parameters of the processes are determined with high accuracy opening or closing the contacts of each of the phases A; V; C, a working three-phase switch and, in case of exceeding the permissible time discrepancies of contacts, record its condition and the possibility of its further operation. Then, when the motion sensor is installed opposite the mechanical moving elements of the switch drive, the output of which is connected to an additional input of a multichannel analog-to-digital converter (ADC), which in turn is connected to a computer, on which, in parallel with the nature of individual pulse-transient processes when switching contacts, the nature of the movement of the moving elements of the drive is reflected, which makes it possible to determine the time intervals between the initial and final values of the drive operation and with the corresponding values during the switching of the contacts, moreover, the joint consideration of the time intervals between the contacts and the time intervals of the drive operation makes it possible to determine the full time cycle when switching three-phase switches with their subsequent comparison with the normalized values.

The implementation of the proposed method is carried out by devices shown in the drawings:

FIG. 1 is a block diagram that implements the method;

FIG. 2 - General view of the VVM-SESH-3-10 vacuum circuit breaker;

FIG. 3 - three magnetic antennas in the form of inductors with U-shaped metal shields: 1 - turn coil of inductance L1 of phase A, 2 - turn coil of inductance L2 of phase B, 3 - turn coil of inductance L3 of phase C; 4 - metal screens;

FIG. 4 - electromagnetic drive of the VVM-SESH-3-10 vacuum circuit breaker, where 1 - trip coils, 2 - trip spring, 3 - adjustable draft, 4 - block contacts, 5 - on coil, 6 - bracket, 7 - buffer;

FIG. 5 - microwave motion sensor TDM DDM-02 SQ0324-0021;

fig. 6 - oscillogram of time intervals between contacts and the drive when the circuit breaker is opened.

The proposed method for remote diagnostics of the time intervals of the contacts of three-phase switches and the operating time of the drive is implemented as follows: in operating electrical networks when switching the contacts of three-phase switches 1 (Fig. 2) currents of three phases: A; V; WITH; create pulse-harmonic transients, in the surrounding space, in the plane of the cross-sections of the conductors, according to Ampere's law, magnetic field strengths arise, which are perceived by three magnetic antennas 2 (Fig. 3), represented by turn coils of inductance L1, L2, L3 located inside P -shaped metal screens to protect against magnetic fields of adjacent phases, the axes of which are perpendicular to the power conductors with current. Antennas are installed on a tripod or on the walls of the cubicles of complete switchgears (KRU), at an insulating distance in voltage from conductors with operating currents of three phases A; V; WITH; for example, for 10 kV - 0.12 m; 35 kV - 0.29 m; 110 kV - 0.7 m., Etc. [Electrical installation rules. Chapter 4.2. Switchgears and substations with voltage above 1 kV. Order of the Ministry of Energy of Russia dated 20.06.2003 No. 242]; the outputs of three magnetic antennas are connected to three inputs of a multichannel analog-to-digital converter (ADC) 3, for example, type E14-140-M, connected to a computer 4, in which, using a special program installed on it, visually in the form of parallel oscillograms (Fig. 6 ) determine the nature of changes in the strengths of magnetic fields from the currents of the three phases A, B, C, represented by the voltage values, with the selected initial or maximum values of pulse-transient processes for each of the three switched contacts of the switch, which allows, when switching contacts, to determine the time intervals between the initial or maximum values of the variable parameters of the processes of opening or closing the contacts of each of the phases A; V; C, working three-phase switches (Fig. 6) and in case of exceeding the permissible time discrepancies of contacts defined in RD 34.45-51.300-97 "Scope and standards of testing of electrical equipment". 6th edition, with amendments and additions as of 01.03.2001. - M .: Publishing house NTs ENAS. 2004. p. 30, or in accordance with the requirements for each circuit breaker, in particular, "Operating Manual 2GK.256.072 RE of the VVM-SESH-3-10 type vacuum circuit breaker", for which the difference in timing of moving contacts for three poles is allowed no more than 0.002 sec, that when comparing the normalized values with oscillograms similar to those shown in Fig. 6, register the need for timely decommissioning of the circuit breaker for repair in order to adjust the contacts of the circuit breaker or replace it. Additionally, for a more complete assessment of the switching processes of switching on and off the switch, it is also advisable to determine the time intervals of the switch drive 5 (Fig. 4), for which purpose a microwave motion sensor 6 is installed in the cover of the device opposite the drive device of the switch with movable elements (Fig. . 5), for example, type TDM DDM-02 SQ0324-0021, with an electrical output signal connected to one of the inputs of a multichannel ADC and a computer, to obtain an oscillogram of the operation of the circuit breaker drive when switching contacts, for example, a vacuum circuit breaker of the type VVM-SESH- 3-10, the proper turn-on time of the drive of which is no more than 0.1 sec, and is defined as the time from the giving of the closing command to the closing of the switch contacts, as well as the intrinsic time of turning off the drive of which is no more than 0.03 sec, and is defined as the time from giving the command to open to opening the circuit breaker contacts, moreover, the joint accounting of the time time intervals between contacts and time intervals of the drive (Fig. 6) allows you to determine the full time cycle when switching three-phase switches with their subsequent comparison with the normalized values.

Claims (1)

A method for remote diagnostics of the time intervals of contacts of three-phase switches and the operating time of the drive in operating electrical networks, characterized by the fact that a group of three magnetic antennas in the form of inductance coils is placed in front of the switches at an isolation distance in voltage, axes directed perpendicular to the terminals of three phases A, B, From a three-phase switch, each in a U-shaped metal screen, the outputs of the magnetic antennas are connected to three inputs of a multichannel analog-to-digital converter, the output of which is connected to a computer, on the general screen of the latter, using a special program, visually, by the type of oscillograms, the nature of the change in the magnetic field strengths of each of the phases during the switching of contacts, represented by the values of voltages proportional to the currents of the three phases, from each of the three changeover contacts of the switch, which determine the time intervals between the single-valued values of the variable parameters of the process ss of opening or closing the contacts of each of the phases A, B, C of an operating three-phase switch, then a motion sensor is installed opposite the mechanical moving elements of the switch drive, the output of which is connected to an additional input of a multichannel analog-to-digital converter connected to a computer, on the common screen of which in parallel with by displaying individual pulse-transient processes during the switching of contacts, the displacements of the moving elements of the drive are recorded, the time intervals between the initial and final values of the drive operation and the corresponding characteristic points during the switching of contacts are determined, and when the time intervals between the contacts and the time intervals of the drive operation are taken into account, the complete time cycle is determined at switching three-phase switches with their subsequent comparison with the standardized values.

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