SU904036A1 - Quick-action current relay - Google Patents

Description

(54) POWERFUL CURRENT RELAY

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The invention relates to electric power industry, namely to the relay protection of the elements of electrical systems,. and can be used as starting blocks of advanced dividing devices.

A device for high-speed protection of electrical installations of alternating current, which reacts to an increase in current and contains functional and logical elements, is known.

D.

However, this device has

lack of speed in advanced division of power systems.

The closest in technical essence and the achieved result to the proposed is a device containing an intermediate current transformer, phase shifting elements, carrying out a phase shift by an angle close to 90 °, two quadras, an adder, a threshold element (comparator), a logic element And two entrances.

an actuator, whether rectangular pulses are formed and a blocking circuit, which produces an actuator enable signal only at the moment of coincidence of the signs of the current and its first derivative. The blocking from incorrect operations in the device at saturation of the current transformer is carried out by a coincidence element, at the output of which at the moments of current transformer saturation there is no signal permitting the operation of the final element 2.

However, such a detuning method leads to the fact that the actuating element is blocked not only when the current transformer is saturated, but also in non-saturation modes, at the moments of non-coincidence by the sign of the current and its first derivative.

This leads to the fact that in the presence of a shutter speed for actuating the actuator, which is mandatory for the condition of detuning from short-term emissions of the first and second derivative of the current, in some cases (short circuit with a small constant time after the passage of current through the maximum, as well as with non-zero Hii: conditions), the time of operation is 1, and the device increases. The cause of the failure of the performer / lorp element in the first moments is due to the delay and its blocking due to the non-coincidence of the current and its derivative in the drop-down portion of the current curve. In the absence of a delay in the actuation of the executive body, it would falsely work in case of load surges and small constant time. In addition, the blocking method described above leads to the appearance of long pauses in the signal of the actuator even without saturation of the current transformer, which is undesirable if it is necessary to dock the device with other measuring units. The purpose of the invention is to increase speed. The goal is achieved by the fact that a high-speed current relay containing a current transformer, to the output of which are connected the first and second phase-turning elements, the first quadrant, the first input of the adder, the comparator, the first input of the first element I and the actuator, are connected to the input The first phase-turning element is connected in series with the first square pulse shaper and the first input of the second element, And, the second input of which is connected through the second driver ougolnyh pulses output of the first phase rotation element to which is also connected to a second quad input, the last output connected to a second input of said smmatora additionally introduced third rectangular pulse generator, the inverter, DELAY element; the OR element and the three-input element AND, the first input of which is connected to the output of the second rectangular pulse former, the second input through the inverter to the output of the first rectangular pulse former, the third input through the third rectangular pulse former to the output of the second phase-coupler , the output through the delay element is connected to the first input of the OR element, the second input of the latter is connected to the output of the second element AND, the output of the element OR is connected to the second input of the first element I. In FIG. 1 is a functional block diagram of a high speed current relay} in FIG. 2 and 3 oscillograms explaining the operation of individual nodes and the device as a whole in a transient mode with current transformer saturation and without it, respectively. (The numbers of the curves on the oscillogram correspond to the numbers of the output signals of the circuit elements), High-speed current relay contains a current transformer 1, to the output of which are connected in series the first and second phase-turning elements 2 and 3, the first quadrant., The first input of the adder 5, to the second input of which is connected the second quadrant 6, the input, the latter is connected to the output of the first phase-turning element 2. The output of the adder 5 is connected in series with a comparator 7 the first input of the first element And 8, isp body element 9. The outputs of the current sensor 1, the first phase rotation element 2 and the second phase rotation element 3 are connected respectively to the inputs of the first, second and third formers 10 to 12 square pulses. The output of the first shaper 10 rectangular pulses connected to the first input of the second element And 13 and through the inverter with the second input of the three-input element And 15, the output of the second shaper 11 rectangular pulses connected to the second input of the second element And 13 and to the first input of the three-input element And 15, the output of the third shaper 12 rectangular pulses is connected to the third input of the three-input element AND 15 whose output through the delay element 16 is connected to the first input of the OR element 17, and its second input is connected to the output of the second second AND gate 13. The output of the OR gate 17 is connected to a second input of the first AND gate 8. The relay operates as follows. The input signal from the output of the current transformer 1 is fed to a phase rotation element 2 connected in series with the same element 3, of which the phase shift leads by an angle close to 1C / 2. The signals from the outputs of elements 3 and 2 are fed to the inputs of the quadrants t and 6, respectively. The inputs of the adder 5 are connected to the outputs of the quadrants k and 6, and the output to the comparator 7. If the amplitude of the control of the polished signal is less than the setting at the output of the comparator 7, the signal corresponds to a logical zero, and with an increase - a logical unit. When the operation of the comparator 7 is exceeded, a signal equal to one appears at the first input of the first element AND 8. The appearance of a signal equal to one at the second input of the first element And 8 is determined by the shape of the current curve, i.e. depends on whether the current transformer 1 is saturated or not. The unsaturated current transformer 1 current signal at the output of the element OR 17, equal to one, appears both at the moments of coincidence of the signs of the current and its first derivative (at the output of the first phase rotation element 2) and at the moments when the signs of the current and its first derivative are not coincide, but the signs of the inverted current and its second derivative (at the output of the second phase-turning element 3) coincide due to the appearance of a signal equal to one at the output of the three-input element 15 And (Fig. 2). the formation of a blocking signal in this device allows to reduce the response time in cases where the actuating element 9 in the transition mode is blocked due to a mismatch between the signs of the current and its derivative. At the moment of saturation of the current transformer 1, the output signal of the OR element 17 is zero, since the output signals of the second element AND 13 are equal to zero due to the discrepancy between the signs of the current and its first derivative and the three-input element 15, due to the discrepancy between the signs of the inverted current and its second derivative. Since in the transition between the saturation mode and the operating mode of the current transformer 1, an ideal transformation can coincide by the sign of the inverted current and its second output; for a certain period of time (Fig. 3), the output of the inlet element 15 requires a delay of about 0.001 - 0.0015 s, performed by element 1b of the delay. This high-speed current relay allows to increase the speed of short-circuit current shutdown. The invention claims A high-speed current relay comprising a current transformer, the output of which is connected in series with the first and second phase rotation elements, the first quadrant, the first input of the adder, a comparator, the first input of the first element I and the actuator, and the input of the first phase rotation element connected in series with the first the shaper of rectangular pulses and the first input of the second element I, the second input of which is connected via the second shaper of rectangular pulses With the output of the first phase shifter, to which the input of the second quadr is also connected, the output of the latter is connected to the second input of the specified adder, characterized in that, in order to improve speed, a third square driver, an inverter, a delay element, and an element are added to it OR and a three-input element AND, the first input of which is connected to the output of the second rectangular impulse generator, the second input through the inverter to the output of the first rectangular impulse generator, t input through the third square pulse shaper to the output of the second phase shifting element, output through the delay element to the first input of the OR element, the second input of the last connected to the output of the second element AND, the output of the OR element connected to the second input of the first element I. Sources of information received into account during the examination 1. USSR author's certificate N 22E661, cl. H 01 H 83/22, 1965. 2. USSR Copyright Certificate f 693501, cl. H 02 H 3/08, 1977.

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fug. pv. Z Editor A. Motyl Tehred M. Teper, Proofreader. Schomak

Order 138/3 Circulation 757 Subscription VNIIPI USSR State Committee

on affairs of inventions and openings 113035, Moscow, Zh-35, Raushsk nab. , d / B

Filial PPP Patent, g, Uzhgorod, st. Projectn, J -

Compiled by G. Semenov FIG.

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Claims (1)

Claim A high-speed current relay containing a current transformer, the output of which is connected in series, the first and second phase-shifting elements, the first quadrator, the first input of the adder, a comparator, the first input of the first element And and the actuating element, the first shaper of rectangulars are connected in series to the input of the first phase-shifting element pulses and the first input of the second element And, the second input of which is connected through the second driver of rectangular pulses with the output of the first phase of the rotational element, to which the input of the second quadrator is also connected, the output of the latter is connected to the second input of the specified adder, characterized in that, in order to improve performance, a third square-wave pulse former, inverter, delay element, OR element, and three-input element And the first input of which is connected to the output of the second rectangular pulse shaper, the second input through the inverter to the output of the first rectangular pulse shaper, the third input through the third shaper spruce rectangular pulses to the output of the second phase rotation element, the output via the delay element to the first input of the OR gate, the second input of the latter connected to the output of the second AND gate, an output of OR connected to the second input of the first element I.