SU657503A1 - Circuit arrangement for short-circuiting protection of electric mains with sectionated and mains redundancy - Google Patents

Description

designed to protect lines with one-sided power.

The purpose of the invention is to expand the functionality of the device, namely, ensuring the fixation of the direction of the short circuit for a network with two-way power,

The goal is achieved by the fact that the known device, containing two parallel current circuits, is formed. connected by a phase measuring current transducer, a second-stage current triggering device, a return delay element and an OR element, the output of a return delay element of each circuit connected to the second input of a second stage starting element of the adjacent circuit, the input to the second input of an OR element the adjacent circuit, the current start-up body of the first stage, connected by inputs to each of the specified phase measuring current transducers, and the output to the input of the alarm element ne two steps, which are connected to the outputs of commented logic elements OR | and the output is from the executive body, the power direction relay, connected by inputs to the input of the measuring converter — to the voltage and to the output of one of the mentioned phase measuring current transducers, and the outputs to the additional inputs of starting organs of the second stage and the holding time element) second stage signaling, contains an additional second stage signaling element, and the inputs of both second signaling elements are connected to the output of the time delay element through, sequentially Connected the break contact of the first-stage alarm element and switching the power direction relay contact.

The drawing shows a functional diagram of the proposed device.

The device consists of two phase measuring current converters with main frequency filters 1 and 2, two current starting organs of the second stage 3 and 4, two elements delayed by return 5 and 6, two logic elements OR 7 and 8, holding element E, current starting organ the first stage is 10, the relay of power direction 11, the measuring transducer of voltage 12, the signal elements of the second stage 13,14 and the first stage 15, as well as the executive body 16. The current starting organs of the second stage. are identical. Each of them consists of the setting item of the settings for the actuation current when transmitting the power in the controlled line in the forward 17 and reverse direction 18, as well as the threshold element 19. The time delay element consists of the start element 2O, . setting elements of the second stage 21; 22 and the first stage 23, as well as the start and return element 24, the capacitor 25 and the reacting element 26, and the element 21 is used to set the device operation time when power is transmitted in the controlled line in the forward direction and using element 22 is set by the device response time when power is transmitted in the controlled pine in the opposite direction. The power direction turnip contains four outputs 27-ZO, two of which 27,

28 included respectively in the current starting bodies, the second stage of 3.4 between the inputs of the threshold epementov 19

and the outputs of the setting elements goku 17.18, the output 29 is turned on between the output of the start element 2O and the inputs of the time of the second epemma of the second stage 21 and 22, and the output 30 is included in the signaling circuit of the second stage 13 and 14. Signalization element 15, the operation of the first stage comprises an output 31, switched on, between the output 30 of the power direction relay 11 and the output of the time delay element 9. The device has a connection between the output of the logic element OR 8 and the input of the start element 20 of the time element 9 via a detachable end Act 32.

The device works as follows.

P

When power is transmitted in a controlled pini in the direct direction, the turnips of the power direction 11 are in the triggered position, with its outputs 27; 28 connect the threshold elements 19 with the adjustments set by the settings for the current 17, the start-up interval 20 is connected by the output

29c is the timing element 21, and the AO output connects the output pole of time element 9 to the alarm element 14 "In this case, the device is set to large current and trip time settings of the second stage. In standby mode, when the current in the power line does not exceed the operating setpoint current, the current signal is sent to the threshold elements of the 19 BbixooHbFe with a phase shift of 120. In the case of a three-phase closure, this phase shift is maintained, and in the case of a two-phase closure closed phase shifted by 180. In the case of a three-phase short circuit on a controlled line in the zone of action of the second stage, the magnitude of the current in the line will exceed; the magnitude of the second-stage actuation current and one of the threshold elements 19 will begin to operate with the fundamental frequency of the input current signal, producing square-shaped signals at the output, the width of which is proportional to the current value in the controlled line. The threshold element 19 of that phase will be reset; the input signal of which goes ahead, in this case, by 12O. The pulses from the output of the threshold element go simultaneously to the return delay element 5 (6) and through the logical element OR 7 to the start element 20 of the time delay element 9. The return delay element 5 (6) triggered gives a potential signal to prohibit the triggering of the threshold element 19 another phase and through the logic element OR 8 - an unlock signal to the element 24 of the time element 9, Kon ™. The capacitor 25 accumulates charges that the element 21 takes in the form of rectangular current pulses, during a setting time, After that srabatshaet responsive element 26 which outputs a voltage signal to the actuator 16, and the signaling element 14. When this mode is controlled by the line, i.e. when transmitting power in the opposite direction, the power direction relay does not trigger and its outputs 27-30 connect respectively the threshold elements with the setting elements of the current settings 18, the starting element 20 with the time element 22 and the output pole of the time delay element 9 with the element Signaling 1.3 In this mode of line operation, the device is set to changed current and time settings, and if a short circuit occurs in the second stage, the device operates with these settings, while The signaling center 13 will n} form a response for protection of the second level when power is transmitted in the controlled circuit in the opposite direction. The second stage can work in two versions: with a time delay that is independent of the current value. To ensure the operation of the second stage with an independent time delay, a detachable contact 32 should be installed, and the output of the logic element OR 8 is connected to the input pole of the start element of the time delay element 9. The value of the continuous output signal of the element 8 during a short circuit in the monitored line does not depend on the fault current in the primary circuits, therefore, the device run time is independent. From the signal of the current start-up organ of the first stage, the turn-off time will not be triggered until the signal from the element OR of the second-stage current channel arrives at the start-up and return element. This prevents false triggering of the device in the event of a fault in the current channel of the first stage. When 1 short circuit disappears in the primary circuits of the monitored line or when it is disconnected, the functional elements of the device return to the B state corresponding to the readiness mode for fiT1T operation, with the exception of signaling episodes, while the capacitor 25 time relay is discharged (charged ) in the forced mode through a low-impedance start and return element 24, which accelerates the preparation of a turn-around time for the action with a predetermined time delay from the repeated signal. Due to the introduction of an additional alarm element, the direction of the occurrence of a short circuit is fixed, and the search for the point of line damage is simplified. Claims An apparatus for protection against short-circuiting of an electrical network with sectioning and network redundancy, containing two parallel current circuits formed in series by a phase current transducer, a second-stage current starting element, a return back-up element, and an OR element, the return of each circuit is combined with the second

the input of the start-up organ of the second stage of the adjacent circuit, and the input with the second input of the logic element OR of the adjacent circuit, the current start-up body of the first stage connected by inputs to each of the indicated phase current transducers, and the input to the input of the first-stage alarm element and the input of the holding element time, the other two inputs of which are connected to the outputs of the logical elements OR, and the output - to the executive body, the power direction relay, which is powered by the inputs to the output of the measuring transducer zovatel voltage and the output of-said-stand from the phase current measuring converters, and outputs - to additional inputs of pus-lauryl bodies of the second stage member and the holding time, the signaling element

The second stage is distinguished by the fact that, in order to expand its functionality, a second stage psyula signal element is introduced, the input of both second stage signal elements being connected to the output of the time element through the series connected break contact of the first element

steps and switchings contact of the power direction relay.

Sources of Information taken into account during the examination 1. Application No. 2О4И25 / О.7,

cl. Н О2 Н 3/08, 08.07,74, according to which a decision was made to issue an author's certificate.

2. USSR author's certificate M) 519809, kp. H 02 H 3 / O8, 10.22.74.