SU758376A1 - Device for comparing voltage phases at the ends of power transmission line - Google Patents

Description

The invention relates to schemes for comparing the voltage phases of substations connected by a power line.

A device is known for comparing the phases of voltages of busbars of a substation and a power transmission line 5 interconnected by a switch [ΐ].

To compare the voltage phases of the busbars of the substation, with the power line to the latter, one-sided voltage is applied from the opposite substation.

However, this device cannot be used for ultra-high and ultra-high voltage lines (750 kV and 15 above), since when a line is turned on unilaterally, both the disconnected end of the line and the end from the power side turn on, because of the large capacitive currents 20 telny ~ overvoltage relative to nominal, which leads to damage to the equipment of the line (switches, reactors, insulators and others. ·). 25

It is also known a device for comparing the phases of voltages at the ends of a power line connecting two sub-stations, containing a transmitter:

2

hotstot processing line for installation at both ends of the line, phase comparison units with phase control relay and phase meter, manipulation organs, executive bodies, with the output of each transmitter connected to the output of the high-frequency processing equipment, and the output of each manipulation unit transmitter [2].

This device is designed to compare the voltage vectors at the ends of the transmission line when the line is on at the moment of occurrence of short circuits on the line itself or outside it.

However, this device in this form cannot be used to compare the phase vectors of substation busbars when the transmission line is disconnected, since it takes considerable time to prepare the voltage phases of two substations for phase and their slip speed, which is not allowed for these voltage classes.

The purpose of the invention is the provision

simultaneous switching on of the power line at both ends by crawl 758376 4

"Phase voltage of both substations with line disconnected.

This goal is achieved by the fact that in a known device for comparing voltage phases at the ends of power lines connecting two substations containing transceivers, high-frequency processing equipment for installation at both ends of the line, phase comparison units with a phase control relay and a phase meter ^ organs manipulations and executive bodies, with This the output of each of the transmitters is connected to the output of the high-frequency processing equipment of the line, and the output of each manipulation unit to the control input of its transmitter, in achestve organ manipulation used transformers

voltage, the primary terminals of each of which are used to connect to the bus station of their substation, the secondary winding is connected to the input of the control of the corresponding transmit. Each phase comparison unit is equipped with an intermediate transformer, a rectifier and a capacitor, with the primary winding of the intermediate transformer connected to the receiver power supply circuit with a direct current, a rectifier is connected to the secondary winding circuit of the intermediate transformer, to the output terminals of which is connected a capacitor, a phase meter and a relay winding control phase, the contact of which is included in the circuit of the executive body.

To compensate for the phase angle between the voltage vectors of the transmitting and receiving substations at the receiving substation, an adjustable resistor is included in the transmitter's control circuit.

FIG. 1 is a schematic diagram of the comparison of voltage phases at the ends of the transmission line; in fig. 2 is a diagram of the commands to turn on the switch and start the high-frequency apparatus to transmit a pulse through the high-frequency channel to the switch of the opposite end of the line; in fig. 3 - high-frequency pulses of the transmitter (solid lines), the transmitter of the opposite end of the power line (dashed lines) and the anode currents of the output lamp of the receiver (shaded rectangles); in fig. 4 shows the dependence of the current in the reference unit and the phase control relay on the angle between the voltage vectors of the compared phases.

A device for comparing the phases of voltages at the ends of the transmission line contains a transmission line 1 connecting two substations 2 connected through line switches 3.

At each of the substations, high-frequency equipment is included in line .1

processing 4 and transceivers 5 and 6.

Transmitters 6 are connected via switches 7 and adjustable resistor 8 (at the receiving substation) to the secondary windings of the voltage transformers 9. The primary terminals of each are connected to the buses of their substation 2. To the receiver 5 through the switch 7, the primary winding of the intermediate transformer is connected 10, through which the receiver is powered by direct current, and a rectifier 11 is connected to the secondary circuit of the intermediate transformer 10, to the output terminals of which are connected

• 15 · capacitor 12, phase meter .13 and winding of phase control relay 14, the contact of which is included in the circuit of the executive body to start a high-frequency apparatus containing control key 15, switch 7 and intermediate relay winding 16, the contact of which together with the winding of intermediate relay 17 included in the circuit of the executive body for inclusion

25 switches 3.

The device works as follows.

When the power line 1 is de-energized, the voltage from the voltage transformer 9 is applied to the input of the transmitter 6 from the busbar of each substation 2 ».

This voltage is controlled by the transmitter 6 according to the principle that is applied to the differential ^{33 of the} three-phase high-frequency protection (transmitter manipulation). Due to this, the transmitters b send high-frequency pulses to their receiver 5 at both ends of the line and through the line

49 1 in the receiver 5 of the opposite end at intervals of half-period of industrial frequency.

The phase of these pulses corresponds to the “phase of the voltages of each substation.

15 '"Receivers 5 receive high-frequency pulses from both their transmitter 6 (see Fig. 3, solid lines) and transmitter b of the remote end of line 1 (see Fig. 3, dashed lines).

The shift between the voltage vectors of its and the remote ends of the line * of transmission 1 corresponds to the interval between the pulses of its and

55 remote, transmitters 6.

In the proposed device for comparing the voltage phases at the ends of the transmission line, the transmitter b is controlled at each end of line 1 by currents from voltage transformers of 9 substation buses.

High Frequency Phase Comparison

pulses occur in receivers 5,

,, receiving high-frequency signals

five

758376

6

from transmitters of both ends of power line 1.

Power receiver 5 via the constant current switch 7 and the primary winding of the intermediate transformer 10, which is included in the anode circuit output lamprophyllite ^e nN receiver 5.

Through the secondary winding of the intermediate transformer 10 and the rectifier 11 is powered phase meter. "13 and the relay control phase 14. ' ^and

When the transmitters 6 do not work and the receivers 5 do not receive signals, the output lamps of the latter are open and a direct current flows in the anode circuit of each of them (about 10 mA), 15

called quiescent current.

In this case, the EMF in the secondary winding of the intermediate transformer 10 is not induced, since the magnetic flux in its core does not change 20 and the current in the circuit of the phase meter 13 and the phase control relay 14 is zero.

When receiving a high-frequency signal from either of the transmitters b (or from both at once), the output lamp of the receiver closes and the current in its anode circuit disappears. ,

When the phase vectors coincide in phase, the transmitters b at both ends of the line operate simultaneously, and the intervals between the high frequency pulses of their transmitter b are filled with high-frequency pulses coming from the remote end of the line (by applying voltage to one of the end of the line in antiphase), ³ and both receivers 5 continuously receive high frequency signals. While the current in the circuit of the phase meter 13 relay control phase 14 is missing,

If the voltage vectors differ in phase, the transmitters at both ends of the transmission line work in this case non-simultaneously, and as a result, the intervals between the pulses remain unfilled. 45

In the high frequency reception breaks, rectangular pulses appear (see Fig. 3, rectangles obscured) because when receiving high-frequency signals, the rest current in the anode circuit of the output lamp of the receiver 5 disappears, and it reappears in the intervals between them.

Through the intermediate transformer 10 is transformed, mainly, the main harmonic of 50 Hz, emitted from the rectangular current pulses in the output circuit of the receiver 5.

The current from the intermediate transformer 10 after rectifying it with a full-wave rectifier 11 and a smoothing capacitor 12 enters the windings of the phase meter 13 and the phase control relay 14.

The magnitude of the current in the circuit of the phase meter 13 and the phase control of the phase 14 depending 65

from the phase angle between the compared voltages is given as a phase characteristic in FIG. four.

Simultaneously with the command to turn on the switch 3 (see Fig.2), the control key 15 through the switch 7 and the disconnecting contact of the phase control relay 14 and the intermediate relays 16 and 17 is given a pulse by the contact G: turning on the switch 3 of the opposite end of the transmission line. ·

To compensate for the phase shift of the voltage of the opposite end of the line, due to the time of passage of the high-frequency signal at the said end of the transmission line, compensation is provided for this phase shift by means of an adjustable resistor 8.

The device allows comparing the phases of voltages of two substations when the line is de-energized in the process of turning them on for parallel operation and thereby preventing damage to high-voltage equipment excluding the one-side inclusion of the line under voltage.

Claims (2)

Claim 1. A device for comparing voltage phases at the ends of a power line connecting two substations, containing transceivers, a high-frequency processing unit for installing at both ends of the line, phase comparison units with a phase control relay and a phase meter, manipulation units and actuators In this case, the output of each of the transmitters is connected to the output of the equipment for high-frequency processing of the line, and the output of each manipulation unit is connected to the control input of its transmitter, characterized in that power transmission belt from both ends, voltage transformers are used as manipulation organs, the primary winding terminals of each of which are used to connect their substation to the busbars, the secondary winding is connected to the control input of the corresponding transmitter, and each of the phase comparison organs is equipped with an intermediate transformer, rectifier and capacitor the primary winding of the intermediate transformer is connected to the receiver’s power supply circuit with a direct current, in the secondary circuit of the receiver Intermediate transformer included rectifier, to the output terminals of which is connected a capacitor, a phase meter and windings of the phase control relay, the contact of which 758376 eight included in the chain of the executive body. 2. Device pop. 1, characterized in that, in order to compensate for the phase angle between the voltage vectors of the transmitting and receiving substations, at the receiving substation, an adjustable resistor is included in the control circuit of the transmitter.