RU1775794C - Fixed lead time synchronizer - Google Patents

Abstract

Usage: in the electric power industry. to turn on synchronous generators in parallel operation. SUBSTANCE: synchronizer comprises a unit 1 for converting a phase angle into a pulse sequence, a measuring and computing unit 16 as a part of the first 5 and second 6 active filters made of three series-integrated integrating operational amplifiers 2,3,4 and 7,8,9, three subtracting blocks 11.12.13 and three summing operational amplifiers 10.14.15, and logic block 17. The measurement of sliding speed and acceleration is carried out without the use of the differentiation operation and at acceptable values of the gain active filters. A command to turn on the generator circuit breaker is given when the calculated angle and sliding speed fall within acceptable ranges. 1 ill. from VI VI ate VI ju

Description

The invention relates to the electric power industry and can be used to switch synchronous generators into parallel operation.

A synchronizer with a constant lead time is known, comprising a unit for converting the phase angle of synchronized voltages into a pulse sequence, a measuring and computing unit made of two summing and three integrating Operational Amplifiers, and a logic unit at the output of the synchronizer. The main disadvantage of this device is its low accuracy. This is related to the following. To determine the magnitude of the current angle b, the velocity ftfe and the slip acceleration s in the synchronizer, three series-connected integrating amplifiers are used, covered by feedbacks so that their resulting transfer function corresponds to a third order link of the form K

W {p)

ap3 + bp2 + cp + 1

(1)

where K is the gain;

a, b, c are the coefficients of the derivatives;

p-t is the differentiation operator.

On the one hand, the link described by expression (1) has a well-defined bandwidth depending on the choice of the coefficients a, b, e, and is an active filter. The voltage at its output (at the output of the third integrating operational amplifier) is proportional to the current phase angle between the synchronized voltages Uc and Ur. In connection with that. that an integration operation is being carried out in this amplifier at its input, i.e. at the output of the second integrating operational amplifier, the voltage is proportional to the angular slip frequency. It is also obvious that at the output of the first integrating operational amplifier, the voltage is proportional to the angular slip acceleration.

On the other hand, the link described by expression (1). is a computing device capable of solving a third-order linear differential equation. The general solution to such an equation # is usually presented as

X Xi + X2 - (2)

where x is a particular solution of the differential equation without the right-hand side;

10

fifteen

twenty

25

thirty

35

40

45

fifty

55

% 2 is a particular solution to the differential equation with the right-hand side.

The form of the function Ј 1 is completely determined by the ratio of the coefficients a, b, and c for the derivatives. The form of the function depends on the type of the right side of the differential equation, i.e. in the case we are considering, from the law of voltage variation from the output of the phase angle conversion unit to the pulse sequence. To suppress component # 1, it is necessary to select the coefficients a, b, and c accordingly, in order to exclude the oscillatory nature of the change in% 1 and to ensure fast attenuation of the aperiodic components of this value. To fulfill such requirements, it is necessary that the coefficients a, b, and c differ from each other by several orders of magnitude, which is often physically very difficult to implement. At the same time, it is not possible to completely suppress the component% 1 even in the case of a physically difficult to realize selection of the quantities a, b, and c. In this regard, the decision result depends on # 1, which means that this component affects the accuracy of determining the values of 5i, ws, Јs.

The purpose of the invention is to improve the accuracy of the synchronizer.

This is achieved by adding three series-integrated integrating operational amplifiers, three subtracting units and a third summing operational amplifier, the input of which is connected to the output of the phase angle conversion unit, in the synchronizer with a constant lead time in the measuring and computing unit. synchronized voltages in the pulse sequence, and the output to the input of the fourth integrating operational amplifier, the other inputs of which are connected the outputs of the fourth, fifth and sixth integrating operational amplifiers, the inputs of the fifth and sixth integrating operational amplifiers are connected to the outputs of the fourth and fifth integrating operational amplifiers, the outputs of the first and fourth integrating amplifiers are connected to the inputs of the first subtraction unit, to the inputs of the second subtraction unit By connecting the outputs of the second and fifth integrating amplifier and to the inputs of the third subtracting unit connected outputs of the third and sixth integrating amplifiers to the inputs of the first summing amplifier connected to the outputs of the first and second subtracting unit, and inputs to the second adder

the amplifier is connected to the outputs of the first, second and third blocks of subtraction.

The elements entered into the system provide the following:

The fourth, fifth and sixth integrating operational amplifiers form a second active filter, the transfer function of which is the same as that of the first active filter. The third summing operational amplifier allows the input of the second active filter to input a signal that is directly proportional to the signal at the input of the first active filter and is n times different from it. As a result of this, the voltages at the inputs of the fourth, fifth, and sixth integrating operational amplifiers differ from the corresponding voltages at the outputs of the first, second, and third integrating operational amplifiers only by a value determined by component 2 and the coefficient p.

In the first, second and third subtraction blocks, the signals determined by the component% i are suppressed, as a result of which its influence on the measured values of the values of the current angle, speed and slip acceleration is eliminated.

The introduction of new elements and the relationships between them provides a positive effect of increasing the accuracy of the synchronizer.

The essence of the invention is to increase the accuracy of the synchronizer by suppressing the influence of the free components on the result of determining the values of the current angle between synchronized stresses, speed and sliding acceleration.

The drawing shows a diagram of the proposed synchronizer,

The following notation is accepted:

1 is a block for converting a phase angle of synchronized voltages into a pulse sequence;

2,3,4 - the first, second and third integrating operational amplifiers, forming the first active filter 5;

b - the second active filter formed by the fourth, fifth and sixth integrating operational amplifiers 7,8,9;

10 - the third summing operational amplifier;

11,12,13 - the first, second and third blocks of subtraction;

14.15 - the first and second summing operational amplifiers;

16 - measuring and computing unit;

17- logical block;

18 - generator switch on circuit.

In addition, physical quantities are shown which are proportional to the voltages acting in the circuit.

Sinusoidal synchronized voltages of the network 1) s and the generator Ur are supplied to the input of the phase angle conversion unit 1 into a pulse sequence. The voltage Ue proportional to the current phase angle 5 is taken from the output of the block. Voltage 11b is applied directly to the first active filter 5, and

5 to the second active filter 6 - through the third summing operational amplifier 10, which provides amplification of the input signal by a factor of n. Both active filters have the same transfer functions corresponding to the third order link and described by expression (1).

Due to the fact that the input signal applied to the active filters differs in the value of the proportionality coefficient n, signals proportional to Јsi, Јs2. , Ws2, 5i, 62 and removed from the outputs of the integrating operational amplifiers, have the same eigen components Ј1, # 1,% i and different compounded components $ 1, # 22, 1,

# 22, &,% a. The signals from the outputs of the subtraction blocks, to the input of which proportional signals are supplied: Јsi, Јs2 - to the input of the first 5 of the subtraction block; th si, a) S2 to the input of the second subtraction block; d, 62 - at the input of the third subtraction block, they do not contain free components proportional to the angle, velocity, and slip acceleration. These signals are fed to the input of the first 14 and second 15 summing operational amplifiers. In the first of them, the calculated sliding velocity is calculated O) spam using the formula

W 5calc (O s + 6 s. (3)

where teKn is the ON time of the generator switch.

In the second summing operational P n amplifier, the calculated angle is calculated (5 calc by the formula

interrogation 5-b U8-T. On + Ј - (4)

The output voltages of the first and second 5 summing operational amplifiers, together with voltages proportional to the permissible values of the angle of inclusion idop and sliding speed o) 8dop, are fed to the inputs of a logic unit 17 that implements the following conditions:

5

717757948

5Rasch 5dop; . (About calculation У8add. (5)), which allows by subtracting If conditions (5) are fulfilled, then the logs to exclude almost their complete influence block generates a command to turn on the measured angle values, the speed of the generator switch , and slip acceleration supplied to the switching circuit 18. Invention

Claims (1)

Netting allows, unlike the main iso-claims clamps to improve the accuracy of the synchronizer with constant time angle, angular velocity and acceleration of glide-ahead in auto No. 940269, about t l-ni. Differentiated operations are excluded. that, in order to increase vani, accompanied by a large 10 accuracy of the synchronizer, the interference signals along the front and rear measuring and computing units in the front of the pulse pulses are followed by three series-connected intensities from the output of the angle converter of the tagging operational amplifier - phase shift . At the same time, according to the proposed fourth, fifth and sixth, three blocks of the calculation, the conditions for selecting 15 tangles are facilitated and the third summing operational coefficients corresponding to the function amplifier, the input of which is connected to the active filter, provides the physical output of the shift angle conversion unit The feasibility of such filters and the distortion of synchronized voltages includes a measurement error associated with the pulse sequence, and the output is due to the presence of free components in the input of the fourth integrating the results of determining the angle, speed, and the integral amplifier, to the other inputs of which the roots are sliding. The outputs of the fourth are connected; furthermore, the technical advantage of the inventive integrating operational effort is that the accuracy of the bodies is increased, the inputs are also and the sixth operation of the synchronizer will provide, including 25 integrating amplifiers, connecting the generators for parallel operation, respectively, to the outputs of the fourth and p - without errors in the angle and sliding speed of the integrating amplifiers, in ladies and thereby prevent possible WHO-subtractor connected to the first unit The yields perturbation during synchronization, communication - the first and fourth rows associated with integrating current surges and dips amplifiers 30, to the inputs of the second block subtraction voltage. This ensures that the outputs of the second and fifth required quality of electric energy of the integrating amplifiers are not connected, and the outputs of the third and sixth integrating electric power sources are connected to the inputs of the electrical receivers and the trouble-free operation of the third subtraction unit. 35 amplifiers are connected to the inputs the first summing up due to the fact that the parameters of both amplifiers are connected, the outputs of the first and the active filters are the same, the same of the second subtraction unit, and free outputs are connected to the outputs Putting the summing amplifier into the alarm mode is connected after determining the outputs of the first, second, and third blocks of the values of the angle, velocity, and acceleration of 40 subtractions in each filter.