SU1053203A2 - Current dependent time-delay relay - Google Patents

Abstract

RELAY CURRENT WITH DEPENDENT CHARACTERISTICS OF ACTION TIME BY AUTH. St. 866634, characterized in that, in order to expand the use of the relay by providing independent control; the maximum and minimum response times, an amplitude detector has been entered into it, and the source of the reference voltage contains the second resolver, the third third potentiometer, and a current limiting resistor. A diode and an adder, with the inverting and inverting inputs of the second decisive amplifier being connected. through the second potentiometer - to the first input of the adder, and output 41. through the potentiometer to the second input of the adder, whose output is the output of the source of the reference voltage and scha gfi oe oo

Description

FIELD OF THE INVENTION The invention relates to electrical engineering, in particular, to relay protection devices with a dependent characteristic of time, and. Can be applied to protect the electric motor, power lines and transformers. According to the main author. St. 866634 a current relay with a dependent time characteristic is known, which contains a linear AC converter of a protected electrical installation into a voltage proportional to it, a decisive amplifier, one input of which is connected to the outputs of the second linear converter - with a constant voltage source, a starting block connected to the output of the decisive amplifier is a triangular voltage generator, the comparison unit / one output of which is connected to the output of the triangular voltage generator, the other to the output operating amplifier, the first and second inputs of which are connected to the fixed contacts of the switch, the movable contact of which is connected to the output of the decision amplifier, the output of the operational amplifier is loaded on a potentiometer, p is a capacitor-integrated integrating unit consisting of a charging resistor and a capacitor / inverter connected to the output of the comparison circuit, the first electronic switch controlled by the inverter and connected by one End to the output of the potentiometer, the other to the discharge resistor connected connected to the integrator unit capacitor / second electronic key, normally shuntyrundy. The capacitor of the integrating unit and controlled by the output of the starting unit, the third electronic key, controlled by the output of the comparison unit and connected between the constant voltage source and the charging | Zezististor of the integrating unit, reactive unit, one input of which is connected to the ungrounded capacitor plate of the integrating unit, the second to the source of the reference voltage, the output of the reactive unit is the output of the current relay fl . A disadvantage of the known device is the dependent adjustment of the minimum and maximum relay response times, which limits its use and also reduces the reliability of the relay when making adjustments to the indicated values of small values of the charge and discharge currents of the capacitor flowing through the contacts in the circuits .resistances of charge and discharge resistors. . The purpose of the invention is to expand the scope of use of the relay by ensuring independent adjustment of the maximum and minimum response times. The goal is achieved by introducing an amplitude detector into the current relay with a dependent characteristic of the operating time, and the source of the reference voltage contains a second solution; A second and third potentiometers, current-limiting: a resistor, a diode and a sum p, the inverting and non-inverting inputs of the second deciding amplifier are combined a turn of the diode that is not inverting the second decisive amplifier through an amplitude detector to the output of the triangular voltage generator, inverting the input. Through the current limiting resistor is connected to the output of the first decisive amplifier, as well as through the second potentiometer - To the first input of the succinator .9 output - through the third potenter to; the second input of the adder, the call of which is the output of the source of the reference voltage. : i Fig. 1 shows a structural current relay with a dependent characteristic of the Action time; Fig. 2 shows stress diagrams at characteristic points of the circuit; ; A current relay with a time dependent response characteristic contains a linear converter 1 of variable current to proportional constant voltage, the first decisive amplifier 2 with an adjustable gain factor, a constant voltage source, determining the operation current of the relay, starting block .3, block .4 comparison, the generator 5 triangular voltage, the first potentiometer 6, the first electronic key. 7, a second electronic switch 8, a resistor-condensing unit 9, made in the form of series-connected resistors 10i of a capacitor 11, a reactive unit 12, a Useip constant-voltage source, a third electronic switch 13, a discharge resistor 14, an inverter 15, an operating amplifier 16, on-off switch 17, additionally introduced amplitude detector 18. At the same time, the source 19 of the reference gauge consists of a second potentiometer 20, a second decisive amplifier 21, a third potentiometer 22, a current-limiting resistor 23, the diode 24 of the adder 25. The device operates as follows; Linear converter 1 forms from a controlled variable constant voltage U proportional to it, which is supplied to the first input of the first re: shta of its amplifier 2 with adjustable gain, to the second input of which the voltage cpaf aTHBaHBH Uj.p is applied, corresponding to the operation current of the relay Output voltage U2.the first decision amplifier 2 is proportional to the voltage difference U2 J Jcp, where K is the gain of the decision amplifier. The voltage Ug is applied to

input starting block 3, the first input

unit 4 of comparison, to the moving contact of the two-position switch 17 and to the input of the source 19 of the reference voltage. The starting block 3 is made in the form of a null indicator, the output of which changes discretely when the input voltage changes sign. If the input current of the relay exceeds the input current of the relay, the starting block 3 operates and acts on the second electronic switch 8, which de-mutes into the resistor-capacitor nominal unit 9, a capacitor 11, and enables the charge of the capacitor 11 through a resistor 10. Comparison with bloy 4 compares the voltage, Uy at the output of the triangular voltage generator 5 with the voltage (2 at the output of the amplifier 2 and It has

Two discrete output signal values: one at 5 Other at 1/2 Uj.

In the intermittent time, when O-Oy (Fig. 2), the voltage I, of the output of the comparison unit 4 is fed to the input of the inverter 15 and to the control input of the third electronic key 13, while the first electronic key 7 is in the disabled state, since At the output of the inverter 15 there is no control signal, and the third electronic switch 13 is turned on. In this case, a capacitor 11 (voltage C) is charged from a constant voltage source Cljap through a resistor 10.

In the time intervals when and 2 and the state of the first and third electronic switches 7 and 13, respectively, is reversed, and the discharge of the capacitor 11 occurs through the discharge resistor 14, the first electronic switch 7 and the first potentiometer b, To adjust the discharge intensity of the capacitor that let us change the bending time of the current characteristic of the relay, the first potentiometer 6 is connected to the output of the operational amplifier 16, the output voltage of which, depending on the position of the contact of the two-way switch 17, can t have both positive and negative level

The output voltage of the first decisive amplifier 2 is through current terminals, the resistor 23 is applied to the anode of the diode 24, the second potentiometer 20 and the inverting input of the second decisive amplifier 21 with a unit gain factor, the non-inverting input of which is connected to the output of the amplitude detector 18 whose life is constant

0 and equal to the amplitude of the voltage of the triple form, and to the cathode of the diode 24. The second decisive amplifier 21 is loaded on the third potentiometer 22. The signals from the second and third potentiators of the meter are fed to the input of the adder 25, the output of which is received on .:, / -, -. .

(. where p is the division ratio of the second potentiometer 20; y is the division ratio

Third potentiometer.:; : --- ra 22; ;; ,,:. : h; ..; 5npa amplitude value

five

triangular stress; . , forms. . - ;. ; ,, ,,., ::.,: ,,.. right, the voltage on the engine of the second potentiometer is drawn off. 20 / PR ma b - voltage on the slider third of its potentiometer 22, right with with. corresponds to the voltage on the way of the adder 25, which is determined. response threshold of the reacting unit :: ka 12, Fig. 2 |. .;: -. -, -:.;,; -:

five

With an input T9ke, greater current; the relay is triggered, the O phase gradually increases, and when the output voltage level of the output voltage of the source: reference voltage source 19 is reached, it triggers the reactive unit G2,

0 which gives a signal to disable the protected object. /; . At an input current equal to the response time of the ESD relay, the ratio of charge time and discharge of ONS, nsatOR

5 11 during the period following the output of the 1st signal of the generator 5 tr of the coal voltage is minimal, and the value of the voltage levels of the response of the reacting unit 12j, which is removable from the output of the source 19 of the reference voltage, is maximal and equal

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Starting from a certain value of current n (voltage Vg / Uj -rrkiX co.

5 of the corresponding independent part of the current characteristic time, during the whole time of the relay operation, the capacitor 11 is continuously charged, and the voltage level of the actuating unit corresponds to the minimum value, p (jij., KOTopoe with a further increase in current remains constant 1, since the diode 24 opens and the voltage on the inverting input of the second decisive amplifier 21 stabilizes and becomes equal to the voltage on its non-inverted input (voltage drop on the diodes 21 can be neglected), What is the voltage at the output of the decisive amplifier 21 is 0. At the same time, the response time of the relay has a minimum value i With current values in the range between tp and with increasing current, the ratio of the charging time and discharge of the capacitor 11 increases, and the response level of the response unit and accordingly, the response time of the relay is reduced. With these current values, the diode 24 of the source 19 is closed and does not affect its operation. Potentiometers and the switch 17 can adjust the shape of the time characteristics of the relay. If the voltage at the output of potentiometer b is opposite in sign to the voltage, the discharge of capacitor 11 in the discharge cycles occurs more intensely than in the case when the polarities of these voltages are lost. This causes, in the first case, the improvement of the time delay in the dependent part of the time of the current characteristic, ia in the second - its increase. To eliminate the error introduced by the imperfection of the characteristics of the diode 24, the latter can be made in the form of a precision diode based on an operational amplifier. thus, the regulation and graduation of the response time scales and the entire characteristic of the relay is simplified. The removal of regulators from low-current circuits 6 of the circuit: with significantly higher current levels, ensures the greater reliability of the relay.

Claims (1)

CURRENT RELAY WITH DEPENDENT CHARACTERISTIC OF ACTION TIME St. No. 866634, with the exception - that it is so that, in order to expand the scope of use of the relay by • providing independent regulation | the maximum and minimum response times, ': an amplitude detector, and the source 07/05/82 Bull. »41 of the reference voltage contains a second. Resolving amplifier, a second and third potentiometers, a current-limiting resistor, a diode and an adder, the inverting and non-inverting inputs of the second resolving amplifier are combined through a diode, non-inverting. yuschy input of the second amplifier is connected via a casting atsshitudny detector to the output of the triangular-frequency voltage generator, an inverting input terminal through a current limiting resistor connected to the output of the first amplifier casting, as well as through the second potentsiometr- to the first input of the adder, and the output _of po- zhcherez third to the second tentsiometr the adder input, whose output is the output of the voltage reference * gI (Dei? ςπ oe lo co>