SU1651336A1 - Device for phase-comparison carrier-current relay protection of transmission lines - Google Patents

Abstract

The invention relates to electrical engineering, in particular to relay protection of high voltage power lines. The purpose of the invention is to increase speed and selectivity. For this, the input of the manipulation body by the high-frequency transmitter 10 is given a signal proportional to the amount of active power penetrating through the line, obtained in multiplication unit 8. 3 Il.

Description

The invention relates to electrical engineering, namely to relay protection of high voltage power lines.

The purpose of the invention is to increase the speed and selectivity by controlling the variable component of the active power varying with double the frequency of the network.

FIG. 1 shows a functional diagram of the differential-phase high-frequency protection with additional blocks; in fig. 2 -diagram of currents in the differential-phase high-frequency protection; in fig. 3 - functional diagram of the power converter as a multiplier.

The device contains two semi-sets 1 and 2 of protection installed at the ends of power line 3, as well as switches 4 power lines. The half sets are connected to the line through a current transformer 5 and a voltage transformer 6. In addition, the device includes a high-frequency communication channel 7 The secondary windings of transformers 5 and 6 are connected to the multiplication unit 8

The output of multiplier 8 is connected via an isolating capacitor 9, which takes the constant component, passes a variable component of the double frequency of the incoming signal, to the input of the manipulation organ 10.

The manipulation unit 10 controls the high-frequency transmitter 11, the output of which is connected to the input of receiver 12 and connected to the high-frequency equipment of communication channel 7 of the transmission line. The receiver 12 is connected to the executive unit 13. from which a signal is sent to turn off the power transmission switch 4.

FIG. 2 denotes the current h at the output of the current transformer 5. The voltage VG at the output of the voltage transformer b, the voltage Ve at the output of the multiplying unit 8, the voltage VQ after

cl

about cl

from s

coupling capacitor 9, voltage Vii at the output of transmitter 11, current Ii2 in the output circuit of receiver 12, and current from the output circuit of the actuator 13.

The device works as follows.

The voltage at the output of the multiplier 8 can be described by the formula

Ve KjVelscosyp - Vel5cos (2 en + p), (1) where Ve is the effective value of the voltage of the voltage transformer 6;

Is is the effective value of the current transformer current 5;

p is the phase shift between current and voltage;

ft) is the angular frequency of the network;

K - coefficient of proportionality.

The voltage Vg at the input of the manipulation body 10 after passing through the capacitor 9 does not contain a constant component. Using the manipulation unit 10, transmitter 11 produces high-frequency Hz pulses, which are received at receiver 12. At the output of receiver 12, if there are high-frequency pulses, the output current N is zero, and in the absence of B H-signals, the output current appears Ii2, which goes to the executive body 13.

Fig, 3 shows the functional diagram of the power Converter as a multiplier 8,

The circuit contains a triangular pulse generator 14, a pulse width modulus module (PWM) 15 on the operational amplifier in the zero-organ mode, a transistor switch

16, a phase shifter 17, an amplitude modulator 18, a filter 19, and an amplifier 20.

The filter 19 is tuned to an increased cutoff frequency, which makes it possible to obtain a signal as the output signal of the power converter unit, which can be described using the expression (1). With the help of a capacitor 21, the constant component is cut off, and a voltage varying with a double mains frequency (2fe) is applied to the input of the ghf 22.

Claims (1)

Apparatus of the Invention A device for differential-phase high-frequency protection of power transmission lines, consisting of two half sets, each of which is designed as a transformer of current and voltage, designed to be connected to the protected power line, a manipulation unit, the output of which is connected to the input of a high-frequency transmitter, the output of which and the input of the high-frequency receiver are connected and connected to the input terminals of the high-frequency communication channel, the output of the high-frequency receiver is connected to the input for an actuator, the output of which is the output of the device, characterized in that, in order to increase speed and selectivity, each half-set additionally includes a multiplication unit and a capacitor, with the first and second inputs of the multiplication unit being connected to the secondary windings of current transformers accordingly, the output of the multiplication unit is connected via a capacitor to the input of the manipulation organ. 7 (yig1