SU1384158A2 - Filtering relay of power direction - Google Patents

Abstract

The invention relates to electrical engineering, in particular, to relay protection. The aim of the invention is to increase the stability of an inoperative power direction relay by compensating also the first free component of the capacitive current of the line. A series-connected current converter 1, a symmetrical current component filter 2, a first low-pass filter 4, and a first adder 5 form a current channel. The filter of the symmetric component of the voltage 3 and the second low-pass filter 7 form a voltage channel. The output voltage of the adder 9 is proportional to the sum of the two voltages - the symmetrical component of the voltages at the location of the relay and the voltage drop from the line current. The simulation of the capacitive current in the relay is performed using a 10 high frequency filter. The impedance setpoint is set by the attenuator 8. Turning on the attenuator 8 and the additional adder 9 in series with the high pass filter 10 allows for more accurate compensation of the capacitive current of the overhead line. 1 il .. with SS (L

Description

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The invention relates to electric 7 @ nor $ {n, in part to a relay switchboard of high-voltage power lines (OHL) and is an improvement of the technical solution on H 74H15,

The purpose of the invention is to increase the stability of the failure of the power direction relay by compensating also the first free component of the capacitive VoKa line.

The functional diagram of the power direction relay is shown in the drawing.

The relay contains a current transducer to voltage 1, connected by an inlet to the input of the filter — a symmetrical component — some current 2,. output to one input of the first sum of the connected 5 by the output to one input of the comparator 6, the second low-pass filter connected by the input to the output of the filter of the symmetrical component 3, and the output to the other input of the comparator 6, 30 attenuator Ator 8 connected to the output of the filter output is a symmetrical component of current 2, and output to one input of the second adder 9, whose output is connected through a high-pass filter 10 to the other input of the first adder 5, and the output of the filter 3 is also connected to another input of the second adder 9,

Attenuator .8 can be implemented as a voltage gain with an adjustable gain, for example, based on an operational amplifier.

The device works as follows.

Serially connected current transducer 1, the filter of the symmetrical component of current 2, the first low-pass filter 4 and the first adder 5, controls the current channel. The filter of the symmetric component of the voltage 3 and the second low-pass filter 7 form a voltage channel. With the indicated switching on of the elements of the relay, the output voltage of the adder 9 is proportional to the sum of two voltages - a symmetrical component of the voltages at the location of the relay and the voltage drop

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p is not IL from current line, V t g. 1h2Y, where ZT is the proportionality coefficient. According to the T-сrava replacement circuit of an OHL with lumped parameters, the voltage U corresponds to the voltage in the middle of an IL. The free component of the voltage in the f-mid of the lini does not vanish, which provides more accurate compensation of capacitive currents. This explains the use of the T-framed replacement scheme. The longitudinal resistance VL Z is simulated using a differentiator, a current-voltage converter. 1 (transreactor), which gives in the passband of frequency filters the same dependence on frequency as the resistance Z of the overhead line. The setting for resistance Z is set by an attenuator 8. The capacitive current 1 i in the relay is simulated using a 10 high-pass filter, the transfer function of which differs from the transfer function of the filter and low frequency 4 in the current circuit only by the numerator by an amount proportional to P, t . Thus, the output voltage of the adder 5, which is the output value of the current channel, is proportional to the sum of the symmetric component of the total overhead line current and the symmetric component of the capacitive current line overhead line of the corresponding sequences when the overhead line is replaced by the T-shaped substitution pattern.

This inclusion of an attenuator, 8, and an additional adder 9 in series with a high-pass filter 10 allows for more accurate compensation of the capacitive current of an overhead line, which increases the reliability of non-protection of protections using this relay for external damage and commutation VL of ultrahigh voltage, .а also when these lines are turned on to idle. Moreover, the inclusion of the attenuator 9 does not impair the slave, that relay-in-short-circuit mode on .LV-

Claims (1)

Formula invented -.- v te n and Filter relay for power direction according to auth.St. № 741415, about t l and - it is most important that, with the aim , 3 1384158 catches the stability of a non-failable relay by compensating also the first free component of the capacitive current of the link and an attenuator and an adder are added, and the output of the filter is symmetmet: The php component is 1px51. The Mereee adder is connected to the input of the high-pass filter, and the other input of the adder is connected via an attenuator to the output of the filter with a symmetrical current component. :