SU1309321A1 - Device for transmission signals via wires of electric power line - Google Patents

Abstract

The invention relates to the transmission of information. The purpose of the invention is to reduce signal instability. The device contains transformers 1 and 3, wires 2 of the high voltage power line, transmitter 4, inductor (CI) 5 and capacitor (K) 6. The goal is achieved by introducing a chain of CI 5 and K 6 that ensures constant signal voltage on the load resistance of the medium voltage power line. 1 il. Lpnrmt}

Description

The invention relates to the transmission of information and can be applied in the transmission of information along transmission lines without their special high-frequency processing.

The purpose of the invention is to reduce signal instability.

The drawing shows an electrical block diagram of a device for transmitting signals through wires of a power transmission line 10.

The device comprises a first transformer 1, wires, 2 high voltage power lines, a second transformer 3, a transmitter 4, a cathode 5 inductance, a capacitor 6,

A device for transmitting signals by wire transmission line operates as follows.

The first transformer 1 is a 20 supply transformer, and the second transformer 3 is a power transformer and is connected to the terminals of the secondary winding of the first transformer 1 by medium voltage transmission lines.

Let C be the capacitance of a capacitor 6; L is the inductance of inductance coil 5; the resistance of the windings of the first transformer 1, Zp is resistance-30 at resonance between L and C Zg is the resistance of wires 2 high voltage transmission lines — ZP is the load resistance of the medium voltage transmission lines; 35 IP - current signal source. In the noise current coming from the wires 2 of the high voltage power line and about - the voltage of the signal on the resistance Z. U - the voltage of the noise on the resistance Zf-,

Thus, in order to reduce the instability of the signal, it is necessary to reduce the interfering current 1Pv and reduce the change in Ujj with a change in Zj and Z.

The limits of variation of Zg are determined, while considering the high voltage transmission line as a lossless line. The input impedance of the line without the loss of a short circuit is determined from the expression

- from the expression

2b (k.z) JZotg / it, and at idle

ZB (X.XI -JCtg / i, where Z is the characteristic impedance of the line

 B / c „

L. with „. 25

kilometric inductance LINE, kilometric capacity

lines;

/ i is the phase coefficient (, fg is the frequency of the signal; P is the length of the line.

From this it follows that the resistance Zg, depending on the length and load of the high voltage transmission line, varies over a wide range, namely -j t Zg + j со, Obvidu but at (D is the wavelength).

When idling the high voltage line (x.x) when

where 6 is the length of the line; j D is the wavelength, 3,5,7., as well as at the short circuit of the high voltage line

D

The current signal of the transmitter 4 1 "soz (k, s,), when n, n 1,2,4,6,.,

gives a useful voltage signal U

2

on resistance Z, the value of Uo on- follows that Zg-0,

is determined from the expression

O.G + 7. 2,

 (ZTP + ZB) ZT-p-fZg + Zc

at Ip const, the instability of the signal voltage is determined by the change in the resistances Zg and Z, since ZTp const.

With wires 2 of the high voltage power line, a noise current Ipg comes in, which forms an undesirable voltage Un on the resistance Z. Moreover, less than

ETC

the less Un,

Thus, to reduce the instability of the signal, it is necessary to reduce the interfering current of 1pv and reduce the change in Ujj with a change in Zj and Z.

The limits of variation of Zg are determined, while considering the high voltage transmission line as a lossless line. The input impedance of the line without loss during a short circuit is determined from the expression

- from the expression

2b (k.z) JZotg / it, and at idle

ZB (X.XI -JCtg / i, where Z is the characteristic impedance of the line

 B / c „

20 30 35

L. with „25

kilometric inductance LINE, kilometric capacity

lines;

/ i is the phase coefficient (, Ha; fg is the frequency of the signal; P is the length of the line.

From this it follows that the resistance Zg, depending on the length and load of the high voltage transmission line, varies over a wide range, namely -j t Zg + j co. Obviously, when (D is the wavelength).

When idling the high voltage line (x.x) when

where 6 is the length of the line j D is the wavelength, 3, 5, 7, ..., as well as at the short circuit of the high voltage line,

D

(k, s,), when n, n 1,2,4,6,.,

2

50

55

At x, x. When, 2.4

1, .., and also when to, z., When,

, 3,5 ,, ..,,

The limits of change of resistance Z are determined by the power of the first transformer 1. In the 10 kV transmission lines for agricultural purposes, the power of such transformers does not exceed 4000 kVA,

The resistance at the frequency of the signal fg is determined from the expression

, P

2EKU fo

6c- short circuit voltage;

and - linear voltage;

 power transformers;

fg is the frequency of the signal;

X - is the reactive component of the resistance ZTP.

Resistance Z, at the signal frequency g, is determined from the expression 21/3 U f

SKjSTpSO

- S in f,

where is kj

- load factor of transformers.

Taking the ratio, 1, which takes into account, you can take Z..

Consider changing Z when changing

 with

tr

,

7 - 7 Tp

r ..

Q - the quality of the windings of the first transformer 1.

With a series resonance between Zyp and Zg, the resistance Z ntte-30 is very low and the voltage of the signal Uc will drop Q times. Chain L, C is tuned to resonance at the signal frequency, while the resonant resistance35

7 - R -

Where rp resistance

Q. - Q of inductor-40 coil 5

with R p i.

Editor N. Gunko Order 1805/56

Compiled by A. Levitinsk

Tehred M. Khodanich Proofreader d.Obruchar

Circulation 639 Subscription

VNIIPI USSR State Committee

for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5

Production and printing company, Uzhgorod, Projecto st., 4

Let us now consider the change in the resistance Z with a change in Zg taking into account the resonant resistance

five

0

0 5

0

upon

,

- GR CH R

Ze -JXrp,

Thus, the installation of the L, C chain reduces the signal instability due to the constant Z, ie Up const.

Since the interference current Inj coming from the high voltage power line will be shunted by the resonant resistance of the Zp LC chain.

Claims (1)

Invention Formula A device for transmitting signals through a transmission line wire containing the first transformer, the primary winding of which is connected to the high voltage power transmission line wires, and the secondary terminals of the first transformer are connected to the primary winding terminals of the second transformer, the first and second secondary windings of which are connected respectively with the first and second transmitter outputs, characterized in that, in order to reduce signal instability, the first output of the primary winding of the first transform Ator connected to the first output of the inductor, the second output of which is connected to the first output of the capacitor, the second output of which is connected to the second output of the primary winding of the first transformer.