SU1310941A1 - Device for comparing phases - Google Patents

Abstract

This invention relates to electrical engineering, in particular to protection devices. The purpose of the invention is to improve noise immunity. This is achieved due to the fact that rectangular pulses from formers 1 and 2 rectangular pulses of the compared values are supplied to the inputs of each three-input major element 3 and 4, and the outputs of the majority elements 3 and 4 are connected to three-input majority elements 5 and 6 with feedback zyu and in pairs united two other entrances. 3 il. n: U fff / jf. 00 fie.1

Description

t. -13

The invention relates to electrical engineering and can be used when making devices for relay protection and automation of power systems, such as a power or resistance direction relay,

The purpose of the invention is to improve the noise immunity of the device.

FIG. 1 shows a functional diagram of the device, in FIGS. 2 and 3, timing diagrams explaining the operation of the device in various modes.

The device contains the formers 1 and 2 rectangular pulses of the compared values, three-code majority elements 3 and 4 with feedback and two other inputs5 connected in pairs to each of which pbix is connected to the output of the corresponding generator 1 or 2, three-input reverse elements 5 and 6c connection and pairwise connected by two other inputs, to which the outputs of the majority elements 3 and 4 are connected, a four-input adder 7, to the inputs of which are connected the outputs, small-time elements -3-6, and the driver 8 module connected to the output of the adder 7.

Majority elements 3-6 are made on the basis of regenerative switches on operational amplifiers x. Moreover, majority elements 3 and 5 change their state when the characters of the input values coincide, and elements 4 and 6 - if these characters do not match.

The majority elements 3-6 implement the majority logic functions 2-1 Г 2 Тции, respectively, - .Mjjg

where X, 3X, X3, are input signals, the X3 signal due to feedback is equal to the corresponding output signal, and the inversion signs indicate inverse output and inputs in X and XZ.

We will first consider the operation of the device in two modes, when the sinusoidal magnitude E is ahead in fa12

ze, (figa) and when E is lagging in phase from E, (fig. 26),

Denote the output signals of the formers 1 and 2 rectangular pulses, respectively, Е and Ец2. Then for the major elements 3 and 4, according to (1), X, 2.Ei2 and for elements 5 and 6 - X should be accepted,

  X2 With non-zero values of the input

the values of the majority elements according to (1) are bifocal at the output of the signal 1 g

ly 1, J - M, Jg, corresponding to the inverted lagging in phase

the input signal, and the input signals of the element 3 are E and E, element 2j - E & E, element 5 - Mz, and e and element 6 - 1. Consequently, in the first mode of operation (Fig. 2a)

i4, E, 2; m, y,,,

F f

i il fj i

.ЛЧ И2

ha., E ,,.

6 i --- i-l4

The sum of the input adders is

30s

Е m.i: ,,,

where t; - transfer coefficient i-th

adder input.

The modulus of this sum at becomes equal to 0.5 | E, I, which corresponds to the operation of the device.

In the second mode (Fig. 2b) GmL-

ri-, - -J 15

E ,. 1, Е „, Е

u 5

m1, m ;, E, 2; E,

) 5 l- -jJ -И7 L -JJj And I1

The sum of the signals, like the modulus of this cyMMbij, which is the output signal of the device, is zero, which

evidence of its failure.

If necessary, it is possible to ensure that the device does not operate in the first mode and triggers in the second mode by applying the signal E, to the input of the imager 2 pulses, and the signal E to the input of imager 1 (Fig.1),

Under conditions of noise interference with the duration t fj (Fig. 3a), this device does not allow false triggering, despite the fact that the input signal is distorted. If one of the compared signals disappears, for example, E ,, the device also does not work falsely (Fig. 3B), However, it is necessary that the square pulse shaper with the zero input signal retains the previous state. For example, shapers 1 and 2, made in the form of regenerative comparators with a symmetric characteristic, meet this requirement. Here, the Upop Trigger threshold must be above the level of constant low noise. Thus, this device has high noise immunity, which eliminates the possibility of false alarms of relay protection and power system automation in conditions of strong interference and in case of open circuits of measuring transformers and, therefore, increases the reliability of their operation.

Claims (1)

DETAILED DESCRIPTION OF THE INVENTION A phase comparing apparatus comprising two rectangular formers. but f g  A, k jA / 2.,  V 7 7 five 0 pulses from the compared values, two three-input monitorial elements with feedback and two other inputs connected in pairs, which are also connected to two inputs of the four-input adder, to the other two inputs of which are connected the outputs of the above-mentioned majority elements and the module of the module connected to the output adder, characterized in that, in order to increase the noise immunity of the device, additionally introduced two three-input majority elements with feedback and pairwise combined two Other inputs, each of which is connected to the output of the corresponding square pulse generator of the compared values, and the output of each of the newly introduced majority elements is connected to the corresponding pairwise combined inputs of the mentioned majority elements, S f g  k jA / 2., Editor M.Petrova Compiled by T. Shchegolkova Tehred L.Oleynik - Proofreader C, Shekmar Order 1899/51 Circulation 619 Subscription VNIIPI USSR State Committee for inventions and discoveries 113035, Moskvarazh-35 ,, Raushsk nab., d. 4/5 Production and printing company, Uzhgorod, Projecto st., 4