SU1185473A1 - Relay with single supplied quantity - Google Patents

Abstract

A RELAY WITH A SINGLE VALUE, containing cascading connected variable-to-constant conversion unit and smoothing RC-filter, characterized in that, in order to improve speed, control keys are added according to the number of RC-filter links, the output of each of which connected with the corresponding key to the output of the variable-to-constant conversion unit, cascade-connected high-pass filter, rectifier, threshold element, made to the second threshold setting input, connected with an input of a high-pass filter and with an output of a variable-to-constant conversion unit, and a one-shot, i whose output is connected to a key control input. (L

Description

00

ate

four

00

This invention relates to relay protection and can be used as a current relay and for example.

The purpose of the invention is to increase the speed of a relay with a multilink RC filter, as well as to expand the functionality of the relay.

FIG. 1 shows a relay diagram; in fig. 2-diagrams, as shown, her work.

The relay contains a cascade connected variable-to-constant conversion unit 1, a smoothing RC filter 2 and a measuring element 3, as well as controllable keys 4 according to the number of links of the RC filter 2 and cascaded connected high-pass filter 5, rectifier 6, threshold element 7 and a one-shot 8, the output of which is connected to the control inputs of the keys 4.

According to FIG. 2.9 is the signal at the output of the variable-to-constant conversion unit 1; 10 - a signal that would be at the output of the RC filter if it was not controlled by the keys; 11 - the same, but with control; 12 - signal level corresponding to 90% of the average value of the signal at the output of block 1 when it is raised; 13 - signal level corresponding to 10% of the average value of the signal at the output of block 1 when it is lowered; 14 is a signal at the input of the threshold setting of the threshold element 7; 15 - signal at the output of rectifier 6; 16 - signal at the output of the one-shot 8.

Considering the operation of the relay, we will assume that the input resistance of the measuring element 3 is large and the amplitude of the signal ripples at the input of the smoothing filter is 20-30% of its average value.

The cut-off frequency of the high-pass filter 5 is chosen higher than the frequency of the signal ripples at the output of the variable-value-to-constant conversion unit 1. Therefore, in the steady state (Fig. 2), the signal at its output is close to zero and insufficient for triggering the threshold element 7. this is securely locked, and the keys 4 are open. The relay in this case works the same way as the prototype.

With a sharp change in the network mode, the signal at the output of block 1 changes abruptly. In the prototype, the signal 10 at the output of the smoothing filter reaches its steady-state value only after a certain time has elapsed (in Fig. 2, with a positive jump in T (, with a negative value - t. 2-1).

In the proposed relay, the setting time of the signal 11 at the output of the smoothing filter 2 is reduced due to the forcing of its charge, carried out both at positive and negative jumps of the signal at its input (Fig. 2, t

 tl and t t3).

The signal jumps 9 freely pass through the high-pass filter 5 and the rectifier 6 to the first input of the threshold element 7. In it, their value is compared with the threshold defined by the signal level

0 at its second input, which, to avoid unnecessary operation at small jumps (Fig. 2, t 12), is selected dependent on signal 9 at the input of smoothing filter 2.

If the magnitude of the jump is large enough

5 then the threshold element 7 actuates the one-shot 8, which in turn will cause the closure of the keys 4 for a short time At. The signal on each of the capacitors of the RC filter 2 almost instantly reaches the signal level 9 at the output of the variable-to-constant conversion unit 1. After the keys 4 are opened, the smoothing filter 2, charged to the input signal level 9, will enter the established mode in a short time.

The signal level at the input and at the output of the smoothing filter 2 can be any. Therefore, several measuring elements with different dynamic ranges can be connected in parallel to its output.

Thus, the control of the mode of operation of the smoothing filter improves the speed and extends the functionality of the relay.

FIG. Z

Claims (1)

RELAY WITH ONE SUMMED QUANTITY, containing a cascade-connected unit for converting a variable to constant and a smoothing RC filter, characterized in that, in order to improve performance, control keys are additionally introduced into it by the number of links of the RC filter, the output of each of which is connected by a corresponding a key with the output of the variable-to-constant conversion unit, cascaded by a high-pass filter, a rectifier, a threshold element made with a second threshold job input connected to the input m high-pass filter and with the output of the variable to constant conversion unit, and a one-shot, the output of which is connected to the key control input. Figure 1