SU748615A1 - Device for signalling about glaze ice formation on power transmission line wires - Google Patents

Description

(54) DEVICE FOR SIGNALIZATION OF NAVIAL FORMATIONS ON WIRES OF ELECTRICAL TRANSMISSION LINES

I

The invention relates to power engineering and may be used for signaling ice formation on wires. Power lines.

A device for remote signaling of icing on wires of power transmission lines is known, which contains an ice load sensor of a dynamometric type, a high-frequency channel transmitter which generates a high-frequency signal, and a receiver of this signal 1.

This device has disadvantages:

-on the path of an overhead line (VL), transmitters with power sources are installed that are difficult to maintain in winter and therefore the reliability of such devices is low;

- devices for connecting transmitters to overhead lines on the route of the line bypass the linear path, resulting in deterioration of the high-frequency path parameters for the relay protection channels, telephony, etc., and their reliability of operation is reduced;

- on long overhead lines, the installation of several transmitters with devices for connecting to wires is required, with the result that the cost of signaling devices can be significant.

The closest technical solution to the described invention is a device for signaling ice formations on power transmission lines, comprising a transmitter and a receiver, an input single-frequency filter, installed at the ends of the line, and a signal unit connected to the output of the receiver 2.

10 The threshold device of the receiver includes a signal unit that is triggered at a predetermined decrease in the signal level at the receiver input, which corresponds to an increase in line attenuation at the selected frequency when ice is formed on the overhead lines with calculated wall thickness and formation length.

A single-frequency ice signaling device on overhead lines also reacts to a decrease in the signal level at the receiver input in case of damage to the transmitter, high-frequency processing equipment of the line (barrier, high-frequency cable, attachment filter), power line, and this is its drawback.

The aim of the invention is the elimination of false alarms in case of damage to the line, high-frequency processing equipment of an overhead transmission line and a transmitter.

The objective is achieved in that a device comprising a transmitter and a receiver with an input single-frequency filter, installed at the ends of the line, and a signal unit connected to the output of the receiver, is additionally equipped with a comparison unit, a second single-frequency filter, And element, a threshold unit; the transmitter and receiver are dual frequency, with each input of the comparator unit being connected; By the output of the corresponding single-frequency filter, the output of the comparison unit is connected via element I to the input of the alarm unit; the second input of element I is connected via the threshold unit to the output of the second single-frequency filter, whose input is connected to the input of the first single-frequency filter.

The drawing shows a simplified block diagram of the proposed device.

The signaling device contains a transmitter 1, line 2, receiver 3, two input filters 4 and 5, amplifiers 6 and 7, comparison unit 8, threshold unit 9, element 10 and signal unit P.

The device works as follows

Transmitter 1 connected to the power line wire at one end sends two signals of different frequencies f I and f to line 2.

The receiver 3 connected to the line wire at the second end contains two input filters 4 and 5, each of which is set to pass the corresponding frequency (for example, filter 4 passes the frequency fj, and filter 5 passes the frequency fj).

A comparison unit 8 is connected to the output of the input filters 4 and 5. The comparison unit extracts the magnitude of the decrease in the level of each signal (Aai frequencies fi and Aoj frequencies fi) and compares these values. At the output of the comparator block 8, the Wits signal only if the ratio of the magnitudes of the decrease in the levels Aat and Yes j is equal to the preset value, which is constant for the selected frequencies fi and fj and will occur only with increasing line attenuation from the ice.

Thus, the comparison unit 8 performs the function of analyzing the nature of the phenomenon that caused the increase in line attenuation. To determine the maximum allowable wall thickness of ice on the wires

serves as a threshold unit 9, which is triggered by lowering the signal level by an amount corresponding to the increase in line attenuation from ice at a given frequency with an allowable estimated ice wall thickness at the estimated line length. The signal from the output of the comparator block 8 and the threshold block 9 is fed to the signal device AND through element 10. As a result, the signal to turn on the ice melting system will be formed only if an ice line with the maximum permissible wall thickness is formed on the wires.

A decrease in the signal level at the receiver input for other reasons (damage to the transmitter, high-frequency VL processing equipment, line damage) will not cause a signal at the receiver output.

Thus, the device according to the invention makes it possible to eliminate spurious alarms in the event of line failures, high-frequency equipment for overhead lines and the transmitter.

Claims (2)

1.Izrailev R.A., Nikiforov E.P. Remote ice signaling device on power lines. Information materials VNIIE number 48, I960. 2. Mikutsky GV. High-frequency communication channels for relay protection and automation. 1977, p. 280. m sT "WITH