SU1365217A1 - Apparatus for stepped directed overcurrent protection in a.c.network - Google Patents

Description

(21) 3709310 / 24-07

(22) 03/12/84

(46) 07.01.88. Bul № 1

(71) Ural Polytechnic Institute. CM. Kirov

(72) Loa. Lystsova, V.E. Polk and V.P. Fedotov

(53) 621.316.925 (088.8)

(56) Geldüpf Ya.S. Releyn protection of distribution networks.-M .: Energie, 1975, p.213.

USSR Author's Certificate No. 11-88823, cl. H 02 H 3/16, 1984.

(54) DEVICE FOR THE CURRENT DIRECTED STEP OF THE RESERVE IN THE AC NETWORK CURRENT

(57) The invention relates to the field of electrical engineering, in particular, to devices for the relay protection of electrical systems. The purpose of the invention is to increase the convenience of operation. During short circuits in the protection operation zone, the most sensitive triggering organ 2 of the last stage is activated and the signal from its output is fed to the S input of the first trigger 29, briefly appearing at its output. Under the action of protection for tripping on a circuit, any of the steps appears a signal at the output of its forming unit 13 and through the monostable element 25 is fed to the direct input of the executive body 18, which is triggered, and the signal from its output is fed to the switch input, the input of the alarm body 24 on the activation of protection and through the fifth element OR 34 to the R input

but

the first trigger 29. There is a switch off. The second delay element 27 in this mode does not have time to work. The second element And 21 and the counter 38 do not work. The invention improves the reliability of operation of multistage relay protections by covering by self-checking not only the forming unit 13, but also some elements of the starting current organs 2 and the power direction organ 7 of the measuring unit 1, as well as due to the instantaneous input of protection in pa

The invention relates to electrical engineering, in particular, to devices for the relay protection of electrical systems based on static relays.

The purpose of the invention is to increase the convenience of operation.

The drawing shows the functional diagram of the device.

The device contains a measuring unit 1, including starting bodies 2, the number of which is equal to the number of stages of protection. Each triggering organ 2 consists of a matching element 3 connected in series through the conversion element 4 to the first input of the comparison element 5, to the second input of which the reference value driver 6 is connected, the power direction authority 7 consisting of the matching addition element 8 whose output is connected. to the sum conversion element 9, from the subtraction matching element 10, the output of which is connected to the difference conversion element 11, the output of which, like element 9, is connected to the comparison unit 12, which forms block 13, containing in each of the steps elements AND 14, the authorities 15 time delays, the alarm signaling authorities 16 of the corresponding stage, and the first element OR 17, the executive body 18, made on the BAN element, the element NOT 19, the first 20, the second 21, the third 22 and fourth 23 elements And, the body 24 of the alarm system

when the internal short circuit coincides with the self-test mode, for which it takes it out of action. In this case, the disconnection is performed by protecting the damaged element with the shortest time delay, which prevents the disconnection of a large amount of intact equipment, reduces the time that the short circuit currents impact the equipment of the electrical system, and does not impair the stability of its operation. 1 il.

protection tripping, monostable element 25, first 26, second 27 and third 28 delay elements, first 29 and second 30 RS triggers, second 31, third 32, fourth 33, fifth 34, sixth 35 and seventh 36 OR elements, body 37 alarms on protection malfunctions, a counter 38 for registering the number of self-tests of protection, separation diodes 39 by the number of stages of protection.

The device works as follows.

f At the on state of the switch of the protected object, the absence of an emergency situation on it and the healthy state of the measuring unit 1, the signals at the outputs of the latter are absent (the exception is the output of the organ 7 of the direction and the power reacting to the full power, as in normal In this mode, this element can be in the depleted state 5). There are no signals at the S-input and output of the first trigger 29, at the input of the second delay element 27, and its progress, at the second input of the third element OR 32, the second in0 D6 of the third element And 22, the first input the seventh element OR 36, at the input of the first isolation diode 39, at the inputs (an exception may be the second inputs of the elements AND 14

from the forming unit, connected to the output of the power direction body 7 of the measuring unit) and the output of the forming unit 13, at the input and output, of the monostable element 25, at the direct input of the executive body 18, at the second input of the fourth element And 23 and the fifth input that element OR 34.

There are no signals at all inputs of the second element I 21 and at its output, at the second input of the sixth element OR 35 and the counter for registering the number of caMonpcjBepoK protection, at all inputs of the second element OR 31 and its type 4 at the input of the element HE 19, at the first input of the fourth element OR

33, at the first input and output of the third element AND 22, at the S input of the second trigger 30 and its output, as well as at the second input of the seventh element OR 36 and separation diodes 39, the third input of the third element OR 32, the fourth input The fifth element OR 34 and the input of the third delay element 28. There is a signal at the output of the HE element 19 and the first input of the first element AND 20, but there is no signal at the second input of this element associated with the output of the shaping unit 13, therefore there is no signal at the output of the first element AND 20 at all inputs of the third element OR 32 and its output, at the inverse entrance of the executive body 18 associated with it and at the second input of the fourth element OR .38, at the output of the latter, the input and output of the first delay element 26. There is no signal at the output of the third delay element 28, at both inputs of the fourth element AND 23 and et o output, at all inputs of the sixth element OR 35 and its output, at all inputs and outputs of the fifth element OR

34, at the R-inputs of both RS-flip-flops

29 and 30 at the outputs of all separation diodes 39. The protection actuation body 24, the fault alarm authority 37 and the number 38 of the self-test protection 38 do not work.

If in this mode in the circuit of the forming unit 13 there is a malfunction causing the signal at its output, then a signal appears at the second input and output of the first element AND 20, at the inverse input of the actuator 18 and the second input of the fourth element OR 33, at the output the last and the input of the first delay element 26, on the input and output of the monostable element 25, on the forward

The input of the actuator 18, Protection does not work to shut off, since the signal at the output of the executive t of the authority 18 is absent, but after the time set at the first delay element 26, a signal appears at its output and at the input of the alarm protection authority. A signal for defective protection is given. The second and third elements And 21 and 22 do not work at the same time, since the signals do not appear on all their inputs.

5 When an external short circuit occurs in this case, causing the triggering of some triggering organs 2 of the measuring unit 1, the signal from the inverse of the actuator 18 is removed, so

as in the ts signals at the inputs of the second element OR 31, connected with the outputs of the triggering bodies, at its output and at the input of the element

5 NOT 19, the signal at the output of the last element and the associated input of the first element AND 20, at the output of this element, at the first input and output of the third element OR 32, disappears, but the protection

0 will not affect the switch tripping, as there will be no signal at the direct input of the actuator 18, which will disappear from the output of the monostable element 25 after a time sufficient for the protection to trip, after it is input to this element.

In case of an external short circuit, when the elimination of damage occurs by the protection of the damaged element, the triggering organs of the measuring unit 1, which react to external circuits, shortly operate. The signal from the output of the most sensitive triggering organ 2 of the last stage of protection is applied to the S input of the first trigger 29, and from its output to the input of the second delay element 27. After the external short circuit is turned off, the signal from the S input of the first trigger 29 is removed, but at its output it is memorized until the signal arrives at the R input.

five

five

0

55

After a time greater than the time of reliable disconnection of a stable external short circuit back-up protection in case of unsuccessful automatic restarting (AR), according to 51136

the signal at the output of the second delay element 27 is fed to the second input of the third element AND 22, to the second input of the third element OR 32, and from the output of the last to the inverse input of the actuator 18 and through the fourth element OR 33 to the input of the first element 26 delays. From the output of the second delay element 27, the signal is transmitted through the first separating diode 39 to the second input of the comparison element 5, the starting organ 2 of the first protection stage, and through the seventh OR 38 element to the first input of the organ 12 comparing the power 7 authority 7 As a result of an increase in the signal at the second input of the element 5 comparing the starting organ 2 of the first protection stage compared to the signal at its first input supplied from the reference value generator 6, the comparison element is triggered and a signal appears at its output de, is yuschems yield of starting Gross carrying body 2 of the measuring unit 1,

Since at the first input of the power comparison organ 12 of the power direction organ 7 an increase in the signal compared with the second input occurs, the signal is triggered and a signal appears at the output of the power directive 7 of the measuring unit 1. From the output of the first starting body 2, the signal goes to the first input of the element And 14 of the first stage of the forming unit 13, to the second input of the fourth element And 23, and through the second 31

and the fourth 33 OR elements - to the input of the first delay element 26. From the output of the power direction organ 7 of the measuring unit 1, the signals are fed to the second inputs of the elements AND 14 of all stages of the forming unit 13. Since the signals are present at both inputs of the element 14 only of the first stage of the forming unit 13, first of all the first stage of protection is tested .

The condition of the element 14 and the time delay element 15 and the signaling body 16 of the first stage of the forming unit 13 is in good condition. The signal appears at the output of the latter and through the first element OR 17 and the monostable element 25 is fed to the forward input of the actuator.

6

five

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five

0

five

0

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18. There is also a signal at the inverse input of the actuator 18, so it does not work. From the output of the monostable element 25, the signal arrives at the first input of the third element I 22, to the second input of which the signal came from the output of the second delay element 27. The third element, AND 22, operates and, from its output, a signal is applied to the S input of the second trigger 30, appearing at its output. From the output of the second RS flip-flop 30, the post-post signal goes to the input of the third delay element 28, through the third element OR 32 to the inverse input of the actuator 18 and through the fourth element OR 33 to the input of the first delay element 26, to the second input of the seventh element OR 36 and to the inputs of all dividing diodes 39, except for the first, and through the fifth element OR 34, the signal is fed to the R input of the first trigger 29, which disappears at the output of the posg. on the input and output of the second delay element 27, on the second input of the third element OR 32, on the second input of the third element AND 22, on the first input of the seventh element OR 36 and on the input of the first isolation diode 39.

As a result of the disappearance of the signal at the input of the first separation diode 39, the signal at its output disappears and the triggering organ 2 of the first stage returns to the initial state, but the triggering organs 2 of all the remaining protection stages work, since through the corresponding separation diodes 39 the signals arrive at the second the inputs of their comparing parts, and the power direction organ 7 remain in the actuated state. The signal disappears at the output of the first starting element 2 and the first input of the second element OR 31 associated with it, the first input of the AND 14 element of the first stage of the forming unit 13 and the second input of the fourth element AND 23. There are signals at the outputs of all the other starting organs 2 measuring unit, from the outputs of which they arrive at the corresponding inputs of the second element OR 31 and the first inputs of the elements AND 14 of the corresponding steps of the forming unit 13.

The first stage of protection returns to the initial state, and the remaining stages of the forming unit 13 start 13652

they are checked. As a result of the second generation, then the third and t-ak, and then the last stage of the forming unit 13, the signals arrive at the second,. the third and so on, the last inputs of the first element OR 17 and from its output through the monostable element 25 comes to the direct input of the executive body 18. But the last does not work, -saK as there is a signal, and at its inverse input, fed through the third element, OR 32, from the output of the second RS flip-flop 30 after it triggers. From the output of the monostable element 25 and from the outputs of the signaling bodies of the second, third and so on of the last stage 16 of the forming unit 13, signals are sent to all inputs of the second element I 21, 20 from the output of which a signal is fed to the input of the counter 38, which records the number self-protection checks, through the sixth element OR 35 - to the R input of the second trigger 30, and through the fifth 25th element OR 34 to the R input of the first trigger 29. The counter runs, the signal at the output of the second RS trigger 30 disappears, on the associated with it inputs of separation diodes 39, wto zo ohm input and output of the seventh OR gate 36, the third input and output of the third OR gate 32, the fourth input and the output of the fifth OR gate 34, the input and output of the third delay element 28. The starting organs 2 of the second, third and so on of the last stage of protection, as well as the power direction authority 7 of the measuring unit 1, return to the initial state, as a result of which the signals at the inputs of the elements 14 and the form of the lean unit 13 and the output, the input and output of the monostable element 25, the direct input of the executive body 18, at all inputs and outputs of the second element I 21.

The signals at the inputs and the output of the second element OR 31, at the inputs and output of the fourth element gQ of RSHI 33, at the input of the first delay element 26, at the second input and output of the sixth element OR 35, at the first input and output of the fifth OR element 34 disappear. , on the K-inputs of the first 29 and second gg 30 triggers. The device returns to its original state. The first element 26 of the delay in this mode does not have time to work, since its action is more

35

g 5 0 5 about 0 5

Q g

five

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above the total operating time of the first and last steps of the first defense. The time of the third delay element 28 should be greater than the time for resetting the starting state 2 of the first stage of protection after checking it, in order to prevent the signals at both inputs of the fourth element AND 23 from coinciding in the process of checking the other stages when it is not superimposed short circuit.

In this way, the self-test is carried out first at the first and then at all other levels of good protection. The fact of a successful self-test is recorded by the counter 38.

If during the self-test of the first stage of protection, the triggering organ 2 of the measuring unit 1 or the elements 14-16 of the forming unit 13, or the first element OR 17 or the monostable element 25, are common for all the stages of protection, then the signal on The output of the latter is not according to Wits. The third element AND 22, connected by the output with the S-BXO- house of the second trigger 30, will not work, since there will be no signal at its first input. After the time set at the first delay element 26 has elapsed, the signal is outputted at its output and sent to the input of the protection failure signaling authority 37, and through the fifth OR 34 element to the R input of the first trigger 29. The alarm control 37 triggers about faults in protection, and protection returns to its original state, since the signal disappears at the input of the first RS flip-flop 29, at the input and output of the second delay element 27, as well as at all the elements connected with it.

Thus, malfunctions in the first stage of protection are revealed during its self-tests.

If the self-test mode of the first protection stage imposes a short circuit in the zone of action of its second stage, then the second stage trigger body 2 will be activated, from the output of which, through the fifth input of the fifth element OR 34, the signal arrives at the R input of the first trigger 29. As a result, signal at the output of the first RS trigger. 29, at the input and output of the second delay element 27 and associated

913

with it, the elements of the self-test mode are terminated and the protection is immediately put into operation. The likelihood of occurrence - the specified mode is much higher when the elements of the first protection stage are in a failed state, when it is removed from operation for a long time, since the self-test time of the first, fastest, protection stage is very short.

Thus, protection failure is prevented when the short circuit mode coincides in the zone of its second stage with the first stage self-test, since even in the first stage of a malfunctioning state, the protection is put into operation and will act to disable it with its correct steps.

If, during the self-test of protection, its first stage, as well as the first element OR 17 and the monostable element common to all stages, will be in good condition, but the starting organs 2 or elements 14-16 of the forming unit 13 will fail in any of the remaining stages as a result of a malfunction that has arisen in them, the signal at the output of the signaling body 16 of the failing stage does not work, there will be no signal at one of the inputs of the second element 21 and its output connected through the sixth element 35 or 35 with the R input of the second trigger 30.

After the time set at the first delay element 26, the signal is turned on at its output and is transmitted to the input of the security alarm signaling authority 37 / and through the sixth OR 35 element to the R-input of the second trigger -29. The signaling fault protection unit 37 triggers, and the protection returns to its original state, since the signal at the output of the second RS flip-flop 30 disappears, as well as on all the elements connected with it.

Thus, you are faulty in all but the first protection step when they are self-tested.

If a short circuit is imposed on the self-test mode of the indicated protection stages in the zone of action of its first stage, then the first stage start-up body 2 of the first stage will operate, which after a successful self-test will

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zero in the initial state. From the output of this element, the signal arrives at the second input of the fourth element AND 23. At the first input of the fourth element AND 23, associated with the output of the third delay element 28, the signal arrives after a time sufficient to return to the starting state 2 of the first protection stage after the termination of the self-test mode and the start of the self-test of all other stages, since from the output of the second RS flip-flop 30, the signal is simultaneously fed to the input of the third element. 28 delay and through the fifth element OR 34 to the R input of the first trigger 29, disappears at the output of the last, at the input and output of the second delay element 27, at the input and output of the first isolation diode 39 and at the second input of the matching part 5 of the first starting element 2 measuring unit 1. From the output of the fourth element I 23, through the sixth element OR 35, the signal enters the R input of the second trigger 30, disappears at its output and all elements associated with it. As a result, the self-test mode is terminated, the protection is immediately put into operation and the switch operates and turns off. In this way, the protection fails when the short circuit in the zone of action of its first stage coincides with the self-test mode of the other stages, in which the protection is in the selected state.

If in the normal mode of operation of the protected object there is a malfunction in the measuring unit 1, causing the signal at the output of one of the current organs 2, then the signal through the second element OR 31, through the fourth element OR 33 enters the input of the first delay element 26. After the expiration of time, us--. delayed on the first delay element 26, the signal appears at its output and enters the input of the protection failure signaling authority 37, through the fifth element OR 34 to the R input of the first trigger 29, and through the sixth element OR 35 to The R input is a second trigger 30. The security fault signaling authority 37 triggers, and its self-test mode is prohibited. Therefore, in the event of a specified failure in

111

aycicpBOM authority 2 of the last stage of protection will not be self-tested.

The device operates in a similar way if the starting current organs do not return to the initial state after the trip protection action.

In the event of short circuits in the zone of protection operation and its actuation as the main or backup, the most sensitive triggering organ 2 of the last stage also triggers and the signal from its output is fed to the S input of the first trigger 29, briefly appearing at its output. Under the action of protection on tripping on a circuit, any of the steps appears a signal at the output of its forming unit 13 and through the monostable element 25 is fed to the direct input of the executive body 18. In the inverse input of the executive body 18, the signal in this case is absent, as a result the triggering of the triggering bodies 2 of the measuring unit 1, the signals from their outputs through the second element OR 31 are fed to the input of the element HE 19, the output of which and the first input of the first element AND 20 connected with it disappears. At the second input of the first element AND 20, associated with the output of the monostable element 25, the signal is received, but at the output of the first element AND 20, at the inputs and output of the third element OR 32 and at the inverse input of the actuator 18, there will be no signals. The actuator 18 triggers and the signal from its output is fed to the switch input, the input of the protection actuation body 24 and, through the fifth element OR 34, to the R input of the first trigger 29, the switch is turned off, a signal is generated protection and the signal disappears from the output of the first RS-trigger 29. The second element 27 of the delay in this mode does not have time to work ..

Since the short circuit is switched off along the circuit of one of the stages that operated first, the second element 21 and the counter 38 do not work. In case of short circuits in the zone of action of the second stage of protection, the signal at the output of the first RS flip-flop does not appear at all, since from the output of the graduated start-up organ 2

17 -12 measuring unit 1, the signal goes to its S-input, and from the output of the start-up organ 2 of the second stage through the fifth element OR 34 - to the R-input, and the signals disappear when the protection returns to the inputs of the first RS flip-flop non-simultaneous: first a signal at the S input and then at the R input, since the latter is connected to the output of the actuator 18.

The application of the proposed device will increase the reliability of the operation of multi-stage relay protections due to self-checking coverage, revealing faults leading to failure of the protection not only of the forming unit 13, but also of some elements of the starting current organs 2 unit 1 (in this case, elements 5 and 12 of the named bodies), as well as due to the instantaneous introduction of protection into operation when the internal short circuit coincides with the self-test mode, for which is derived from action. In this case, the disconnection will be performed by protecting the damaged element with the shortest time delay, and not by the back-up protection of adjacent elements, which will prevent a large amount of intact equipment from shutting down, reduce the time it takes for the electrical system to short-circuit currents, and will not impair its stability.

The schematic and description of the proposed AC device are given for multi-stage current directional protection, containing, in general, n steps and operating for all types of short circuits,

In the case of using the proposed device for a multistage current directional protection of zero sequence, it becomes possible to monitor the good condition of the power direction authority 7 of the measuring unit 1, for a black output it should be connected to the auxiliary input of the second element OR 31. In this case, a signal will appear a malfunction in this body, causing it to operate in a normal operating mode or not to return to the initial state after the trip protection action.

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The proposed device can be used for multi-stage distance protection. In this case, the measuring unit 1 will include remote starting bodies 2, the number of which is equal to the number of protection stages, and the swing protection block body 7 connected to the outputs of the measuring current transformers and voltages and outputs associated with the inputs of the forming unit 13, the first inputs of each of the elements And the forming unit are connected to the outputs of the remote starting bodies of the corresponding protection level and their second inputs are connected to the output of the swing protection body 7, which is also connected to the S input of the first trigger 29 (in conjunction with the last current control, 2) and the auxiliary input of the second element OR 31, output the remote starting organ 2 of the first stage is connected to the second input of the fourth element I 23, the output of the remote starting body 2 of the second stage to the fifth input of the fifth element OR 34, the outputs of all separation diodes to the outputs of the converting parts of the summed electrical values Remote triggering bodies 2, and the output of the seventh element OR 36 - with the input element of the block 7 of the protection block when the measuring unit I swings. Otherwise, the circuit of the device and its operation do not change.

If the remote starting protection bodies are omnidirectional, then its measuring unit will contain a power direction organ, the inputs of which are connected to the outputs from: current measuring transformers and. voltage, the output is connected to the third inputs of all elements AND the forming unit 13, and the output of the seventh element OR 36, in addition, is connected to the output of the conversion element of the sum of the summed electrical values of the power direction of the measuring unit 1.

Claims (1)

Invention Formula A device for current directional stepped protection in an alternating current network, comprising a measuring unit, including starting ones Q 5 about 5 about Q g Q five 55 714 organs each with a comparison element at the output, the number of which is equal to the number of protection stages, the power direction authority with the comparison unit at the output, while the output of the current sensor is connected to the inputs of the triggering bodies and the first input of the power direction authority, to the second input of which the sensor output is connected forming unit, which includes the number of stages of protection of the chain of series-connected elements I, the time delay body and the alarm body of the corresponding stage, whose outputs are connected input of the first OR gate, the first, second and third AND gates, the first, second and third delay elements, the second, third, fourth and fifth elements ,, OR element. NOT, monosta: - a mobile element, an executive element, the output of which is connected to the discharge circuit, a protection authority and the second input of the fifth element OR, the first RS trigger, the count of the number of self-conductors, while the outputs of the starting ones bodies are connected to the inputs of the second element OR, the output of which through the element is NOT connected to the first input of the first element AND, to the second input of which the output of the first element OR and the input of the monostable element is connected, the output of which is connected to the second the actuator and the first-. I input the second element And, the output of which is connected to the counter registering the number of self-protection protection and the first input of the fifth element OR, the third input of which is connected to the output of the first delay element, and the output to the R input of the first RS trigger, the output of which connected to the input of the second delay element, the output of which is connected to the alarm signaling body of protection, the S-input of the specified trigger is connected to the output of the triggering organ of the last stage, the outputs of the second and subsequent signaling bodies of the corresponding protection stages forming unit are connected to the inputs of the second AND gate, characterized in that, in order povsh1e- no easy operation, it introduced a second RS-flip-flop, the fourth AND gate, and a seventh elements schestoy 15136 OR, separation diodes according to the number of protection stages, with the output of each of the triggering organs connected to the first input of the element AND forming unit, respectively, to the second inputs of which the output of the power direction organ is connected, and the inputs of the comparison elements of the triggering organs to the input the power direction comparison unit of the power unit is connected to the output of the seventh element OR, the output of the second delay element is connected to the first input of the seventh element OR, and the anode of the separation diode first stage, and the second input of the third element OR, the output of which is connected to the first input of the executive body and the second input of the fourth element OR, the first input of which is connected to the output of the second element OR, and the output of the fourth element OR is connected to the input of the first delay element, the output of the M716 nostable element is connected to the first input of the third element AND, the output of which is connected to the S-input of the second RS-flip-flop, the output of which is connected to the second input of the seventh element OR, the anodes of the separation diodes of the second and subsequent starting organs, the third input of the third element OR, the fourth input p of the element OR, and the input of the third delay element, the output of which is connected to the first input of the fourth element AND, the second input of which is connected to the first input of the second element OR, and the output of the fourth element AND connect It is connected to the third input of the sixth OR element, the second input of which is connected to the output of the second AND element, the first input of the sixth OR element is connected to the third input of the fifth OR element, the fifth input of which is connected to the second input of the second OR element, and the output of the sixth OR element is connected to the R-input of the second RS-flip-flop.