SU1112467A1 - Device for providing protective de-energizing in a.c.network - Google Patents

Abstract

A DEVICE FOR VOLTAGE DISCONNECTION IN THE AC NETWORK, containing a measuring unit, consisting of starting current organs according to the number of protection stages, a power direction organ, the first input of which is connected to the inputs of the starting current organs and is the input of the measuring unit connected to the current sensor a the second input of the power direction organ is the second input of the measuring unit connected to the voltage sensor, while the outputs of the starting current organs and the power direction organ are you moves measuring unit connected to the inputs of the forming unit, consisting in the number of stages of protection from the last. connected elements And time delays and alarm bodies, and the outputs of the starting current bodies of the measuring unit are connected to the first inputs of the corresponding elements And the forming unit. the second inputs of which are combined and connected to the output of the power unit of the measuring unit power, and the outputs of the signaling bodies of the forming unit through the first element S1I and the monostable element are connected to the second input of the executive body, which is connected to the switch and the alarm signaling organ protection element, NOT, the input of which is connected through the first delay element to the fault signaling authority in the measuring unit, and the output to the first input of the first And element, the second input of which is connected to the soy point (the line of the first element OR and the monostable element, organ sigS on malfunctions in the forming unit, characterized in that, in order to increase the reliability of the device in operation and ease of operation, RSrigger, second, third, fourth, and fifth elements OR, second element AND with a registration counter of the number 4 self-test protection at the output, second and third delay elements, separate diodes, with the output of the last starting current org on the measuring unit is connected to the S-input of the RS-flip-flop, the R-input of which is connected to the output of the third OR element, and the output of the RS-flip-flop is connected via the second delay element and according to the included separation diodes to the outputs of the measuring unit and the inputs of the fifth OR element, output which is connected to the input element NOT, and the outputs of the bodies

Description

signaling of the forming unit are connected to the second, third and fourth inputs of the second element I, the output of the monostable element is connected to the first input, and the first input of the third element OR to the output of the executive body is connected to the output, the first input is connected to the third input delay element, and the fourth input through the third delay element - the output of the second delay element and the second

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the input of the second element OR, the first input of which is connected to the connection point of the output of the first element AND and the first input of the fourth element. OR, the output of which is connected to the fault signaling body in the forming unit, and the output of the second element OR is connected to the first input of the executive body, and the second input of the fourth element OR is connected to the output of the third delay element.

The invention relates to electrical engineering, in particular, to relay protection of electrical systems.

Devices are known for the protective disconnection in AC 1.

The closest in technical essence to the invention is a device for protective disconnection of an AC network, comprising a measuring unit including current starting organs according to the number of protection steps and a MoriHosti direction unit forming a block containing in each step elements connected in series delays and signaling bodies of the relevant level, as well as the OR element common to all levels, the executive body, implemented on the BAN element, In the process of protection, the logical element AND, the logical element NOT, the alarm signaling body in the forming unit, causing the appearance of a signal at its output, the monostable element, the delay element, the signaling element in the measuring unit, causing its long-term response. The known device prevents false triggering of protection in case of malfunctions in the forming unit, which cause the appearance of signals at its output, when the specified mode coincides with external short circuits, at which the measuring relay

block, with prolonged occurrence of signals at the output of the measuring unit, caused by faults in its circuit or failure to return to the initial state of the starting relays after turning off the switch on the protected object, and re-activating switch 2

However, the known device does not detect faults in the forming protection unit, which leads to a failure in its operation when there is a closure in the protected zone. As a result, if these faults occur, the protection function fails, which is especially dangerous if there are no backup protection at the protected object, since repairing the damage in this case will be performed by the protection of adjacent elements, causing a large amount of equipment to be disconnected. In addition, the shutdown of adjacent elements by back-up protection occurs with a significant delay, which causes a long-term effect on the electrical system equipment of short-circuit currents and can lead to a violation of the stability of its operation.

The purpose of the invention is to increase the reliability and ease of use of protection.

The goal is achieved by the fact that a device for protective disconnection in an AC network contains a measuring unit consisting of starting current organs according to the number of stages of protection, an organ. power directions, first input

which is connected to the inputs of the starting current organs and is the first input of the measuring unit connected to the TOKaj sensor and the second input of the power direction organ is the second input of the measuring unit connected to the voltage sensor, while the outputs of the starting current organs and the power direction organ are the outputs of the measuring unit connected to the inputs of the forming unit, consisting of the number of protection stages of the series-connected elements I, time delays and signaling organs The outputs of the starting current organs of the measuring unit are connected to the first inputs of the corresponding elements AND of the forming unit, the second inputs of which are combined and connected to the output of the power unit of the measuring unit power, and the outputs of the signaling authorities of the forming unit are connected to the second input of the executive unit through the first OR element body, made on the element BANGE, the output of which is connected to the switch and the signaling body of protection operation, the element is NOT, the input of which th is connected via a first delay element to the signaling entity fault in the detecting unit, and an output - to the first input of the first AND gate, the second input of which is connected to the junction of the first AND gate and. a monostable element, a fault signaling body in the forming unit, RS-trigger, second, third

the fourth and five elements OR, the second element AND with the registration counter of the number of self-protection protection at the output, the second and third delay elements, separation diodes, while the output of the last starting current body of the measuring unit is connected to the S input of the RS flip-flop, whose R input connected to the output of the third element OR, and the output of the RS flip-flop is connected via the second delay element and according to the included dividing diodes to the outputs of the measuring -block and the inputs of the fifth OR element, the output of which is connected to the input of the element H , Alarm outputs bodies

Formation of the block is connected to the second, third and fourth inputs of the second element AND, the first input of which is connected to the output of a monostable element, and the output is the first input of the third element OR, the second input of which is connected to the output of the executive body, to the third input - the output of the first element delay, and to the fourth input through the third delay element - the output of the second delay element and the second input of the second OR element, the first input of which is connected to the junction point, the output of the first And element and the first input ertogo OR gate whose output is connected to the fault alarm body x in the forming block, and the output of the second OR element connected to the first input of the actuator body, wherein the second input of the fourth OR gate connected to the output of the third delay member.

The drawing shows a diagram of the proposed device.

The device for protective disconnection in the AC network contains a measuring unit 1, including starting current bodies 2, the number of which is equal to the number of stages of the device, and a power direction body 3, forming unit 4, containing elements of AND 5 in each stage, 6 time delays, authorities 7 signaling the work of the corresponding stage, as well as the first element OR 8, the executive. authority 9, made on the BANCH element, first and second elements 10 and 11, element 12, alarm actuation body 13, fault unit in alarm unit 14, monostable element 15, first, second and third delay elements 16 -18, RS flip-flop 19, elements OR 20-23, dividing diodes 2A, second, third, fourth, and fifth counter 25 registering the number of self-protection checks, fault signaling body 26 in the measuring unit.

The device works as follows.

When the switch of the protected object is turned on, there is no emergency situation and the metering state 1 is in good condition, there are no signals at the outputs of the latter (an exception is the output of the power direction body 3, which responds to full power, since this element is in normal mode. may be in a failed state). There is no signal at S-input and direct output of flip-flop 19, at the input and output of the second delay element 17, at the inputs and outputs of all separation diodes 24, at the inputs (an exception may be the input of the forming unit connected to ) and the output of the forming unit, at the input and output of the monostable element 15, at the direct input of the executive body 9, there are no signals at all inputs of the second element 11 and at its output at the input and output of delay element 18, at all inputs of the third element OR 21 and its output associated with the R-in trigger house 19. There are no signals at all inputs of the fifth element OR 23, at its output and at the inputs of the first delay element 16 and NOT element 12. At the output of the first element 16 there is no signal, and at the output of the element 12 and the first input of the first element AND There are 10 signals, but there are no signals at the second input and output of the first element AND 10, there are no signals at both inputs and output of the fourth element OR 22, at both inputs and output of the second OR element 20 and the inverse input of the actuator 9. The authority 13 does not work alarms for triggering protection You are the fault signaling body 14 of the forming unit, the fault signaling body 26 of the measuring block and the registration counter 25, the number of self-tests of protection,, I If in this mode the malfunction occurs in the circuit of the shaping unit 4 causing a signal its output then a signal appears at the second input and output of the first element AND 10, at the input and output of the second element OR 20 and the associated inverse input of the executive body 9, at the input and output of the fourth element OR 22 and connected. there is a fault signaling body 14 in the forming unit, on the input and output of the monostable element 15 and the direct input of the executive body 9 associated with it. The protection does not work to turn off, but a signal is given about the malfunction in the forming unit. The second element And 11 does not work in this mode, since the signals arrive only at its two inputs associated with the output of the monostable element 15 and with the output of the signaling organ of the malfunctioning stage of the forming unit 4. When an external short circuit occurs in this case, causing some current starting organs of the measuring unit 1, the signal from the inverse input of the executive body 9 is removed, since signals at the inputs of the fifth element OR 23 connected to the outputs of the triggered bodies are transmitted to the output and input of the element is NOT 12, the signal at the output of the last element and the associated input of the first element AND 10, at the output of this element, at the input and output of the second element of RSHA 20 disappears. But the protection does not act on the opening of the switch, i.e. There will be no signal at the direct input of the executive body 9, which disappears from the output of the monostable element 15 at a time sufficient for the protection action to turn off, after it is supplied to the input of this element. The first delay element 16 does not have time to work, and the malfunction signal in the measuring unit does not work, because the delay time on it is longer than the time for the protection to turn off by its own backup steps. During an external short circuit, when the elimination of damage occurs by the protection of the damaged element, the starting current relays of the measuring unit 1, which react to external circuits, operate briefly. The signal from the output of the most sensitive start relay 2 of the last protection stage is fed to the S input of trigger 19, and from its direct output to the input of the second delay element 17. After the external short circuit is disconnected from the S-input of the trigger 19, the signal is removed, but at its direct output it is memorized until the signal arrives at the R-input. After a time greater than the reliable time to turn off the stable external short circuit backup protection when unsuccessful reclosure, a signal appears at the output of the second delay element 17 and is fed to the input of the third delay element 18 through the second element OR 20 to the inverted input of the actuator 9 and through the separation diodes 24 to all inputs of the forming unit 4 and the fifth element OR 23. When the forming unit 4 is in good condition, signals appear at the outputs of the first signaling authority 7, then the second, and so on. its last stage are applied to inputs of first OR 8 forming unit and its output alternation monostable element 15 coming t on the forward input executive 9. But actuator does not operate because there is a signal and at its inverted input. From the output of the monostable element 15 and from the outputs of the signaling authorities 7 on the operation of individual steps of the forming unit. 4 si cash flows to all inputs of the second element 11, from whose output a signal is fed to the input of counter 25, which records the number of self-protection checks, and through the third element OR 2 to the R input of the trigger 19. The counter triggers, the signal at the trigger output 19 disappears, the input and output of the second delay element 17, at all inputs of the forming unit 4 and its output, at the input and output of the monostable element 15, at the input of the third delay element 18, at the input and output of the second element OR 20, on the forward and inverse lines of the executive organ 9, at the entrances and exits The second element 11 and 11, at the input and output of the third element OR 21, at the input of the counter 25 and the R input of the trigger 19. The protection returns to its original state and is put into operation. The first 16 and third 18 delay elements in this case do not work, since the time of their operation is longer than the time of the last protection stage. If in the specified mode in the circuit of the forming unit 4 there are faults that lead to the failure of any one or several protection stages at once, the signal at the outputs of the alarm authorities about their operation does not appear, therefore.

is fed to the direct input of the executive body 9, at the inverse of which the signal in this case will not be the signals at the associated inputs of the second element AND And at its output. After a time greater than | In the last operation, a protection step, a signal is received at the output of the third delay element 18 and through the fourth element OR 22 it enters the input of the fault signaling body 14 in the forming unit, and through the third element OR 21 it goes to the R input of the trigger 19. Operates the fault signaling authority 14 in the forma- tion unit, and the protection returns to its original state and is put into operation by its operational steps. The first delay element 16 does not work in this mode, since its duration is longer than that of the third delay element 18. If in the normal mode of operation of the protected object there is a fault in the measuring unit 1, causing the appearance of a signal at the output of one of the current triggering organs. then the signal goes through the fifth element OR 2S to the input of the first delay element 16, and from its output after the time has elapsed, longer than the last protection stage, to the input of the signaling authority 26 about faults in the measuring unit and through the third element OR 21 to R - trigger input 19. The fault signaling body 2 in the measuring unit triggers, and the self-test mode of protection is inhibited. Therefore, in the event of the occurrence of the indicated malfunction in the most sensitive current start-up organ of the last stage of protection, it will not be self-tested. The device acts similarly when the current triggering bodies do not return to the initial state after the trip protection acts. During internal short-circuits, the most sensitive current triggering organ 2 of the last protection stage also triggers, and the signal from its output is fed to the S input of the trigger 19, remembered on his way out. However, under the action of protection on tripping in any of the stages, a signal appears at the output of the forming unit 4 and through the monostable element 15 9111 is absent, because as a result of the operation of the current starting elements of the measuring unit 1, signals from their outputs go through the fifth element OR 23 to the input element NO 12, at the output of which and the associated input of the first element AND 10 the signal disappears, the signal at the output of the first element AND 10 and associated with it through the second element OR 20 inverse input of the final element 9 disappears. Signal From the output of the actuator 9, it is fed to the input of the switch, the input of the protection actuating signaling body, and through the third element OR 21 to the R input of the trigger 19. The switch is disconnected, the protection tripping signal is output, and the signal from the output of the Trigger 19 disappears. The second element 17 of the delay in this case does not have time to work. Since the short circuit is switched off along the circuit of one of the protection stages that operated first, the element 11 and the counter25 do not work. The device also operates in case of external short circuits, when the protection of the damaged element is denied action and the elimination of the damage occurs by the backup steps of this stage. g Thus, when a short circuit on the protected element, as well as external short circuits, accompanied by a failure of the protection of the damaged element, the device acts on the opening of the switch and the signal. The application of the proposed device will improve the reliability of the relay protections due to the timely detection of faults in and. circuits due to self-tests of protection in case of external short circuits, the number of which significantly exceeds the number of internal damages. Protection. will self-check during the time interval between two planned operational checks. The convenience of using such protection is increased, because if a malfunction occurs in its circuit, causing failure in operation, and an external short circuit in its work zone, a signal is given, and no failures in the specified protection operation mode — it is registered by a special counter, which allows the operating personnel to know the number of self-protection checks in the npd time interval between two scheduled checks. The scheme and description of the proposed device for protection of disconnection in the AC network are given for multistage current directional protection, containing in general c stages and acting for all types of short circuits. In the case of using the proposed device for multi-stage current directional protection of the zero sequence, it is possible to monitor the good condition of the power direction organ 3 of the zero sequence of the measuring unit 1, for which its output must be connected to the auxiliary input of the fifth element OR 23. Herewith to be a malfunction signal in this body, causing it to operate in the normal operating mode or not to return to the initial state after the action protection tripping. The proposed device can be used for multistage distance protection. In this case, measuring unit 1 will include remote start-up bodies 2, the number of which is equal to the number of protection stages, and body 3 of swing protection, connected by inputs to the outputs of measuring current transformers and voltages, and codes associated with the inputs of the forming unit 4, 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 body 3 of the protection blocking when the arms, d is also connected to S-input of flip-flop 19 (instead of communication with current body 2) and an additional input of the fifth OR gate 23. The rest of an apparatus and its operation are not changed. If the remote starting protection bodies are omnidirectional, then the measuring unit will contain a power direction authority, the input of which is connected to the outputs of the measuring current transformers and voltage, and the output is connected to the third inputs of all elements of the forming unit 4. The number of isolation diodes will increase one through which the output of the second delay element 17 will be connected to the output of the power direction of the measuring unit 1.

The proposed device can be used for stepped current directional or distance protection. At the same time, the measuring unit 1 will contain two organs (current start; body and power direction organ — for current directional protection; remote trigger body and swing protection locking organ — for distance protection, having a directional distance organ (or three organs), remote triggering organ, blocking protection for oscillations and power direction organ - for remote protection with omnidirectional remote organ), S-input of trigger 19 will be connected to the output of current triggering organ - for current directional protection, to the output of the blocking element of the protection during oscillations - for

the distance protection, the fifth element OR 23 will be absent for the current directional device, since the output of the current starting Organ will connect to the inputs of the HE element 12 and the first delay element 16 and for the distance protection it will contain two inputs, the first of which with the output of the remote start-up organ, and the second is connected to the output of the blocking body for protection against oscillations. The number of isolation diodes will be two for current-oriented protection and distance protection with directional remote bodies and three for distance protection with omnidirectional starting bodies, and the first element 10 will contain two inputs, the first of which is connected to the output of the monostable element 15, and the second is connected to the output of the second delay element 17. In this case, the forming unit will contain one element, with two for current directional and remote with directional remote body protection, or with three inputs for distance protection with non-directional distance body.

Claims (1)

DEVICE FOR PROTECTIVE CIRCUIT BREAKING IN THE AC NETWORK, containing a measuring unit, consisting of starting current elements according to the number of stages of protection, an organ of direction of power, the first input of which is connected to the inputs of the starting current organs and is the first input of the measuring unit connected to the current sensor "and the second the input of the power direction organ is the second input of the measuring unit connected to the Voltage sensor, while the outputs of the starting current organs and the power direction organ are the outputs measuring unit connected to the inputs of the forming unit, consisting of the number of stages of protection from subsequently connected elements And, time delays and alarm organs, the outputs of the starting current organs of the measuring unit are connected to the first inputs of the corresponding elements And of the forming unit, the second inputs of which combined and connected to the output of the power direction organ of the measuring unit, and the outputs of the signaling organs of the forming unit through the first OR element and a monostable element t are connected to the second input of the executive body, made on the element BAN, the output of which is connected to the circuit breaker and the signaling element about the operation of the protection, the element NOT, the input of which is connected through the first delay element to the signaling element about the malfunction in the measuring unit, and the output to the first input of the first AND element, the second input of which is connected to the connection point of the first OR element and the monostable element, a malfunction signaling organ in the forming unit, characterized in that, in order to increase the reliability of the device in operation and ease of operation, it introduced RS trigger, the second, third, fourth and fifth elements OR, the second element AND with a counter for recording the number of self-checks of protection at the output, the second and third delay elements, diodes, while the output of the last trigger the current organ of the measuring unit is connected to S-input of the RS-flip-flop, the R-input of which is connected to the output of the third OR element, and the output of the RS-flip-flop is connected through the second delay element and, according to the switched-on dividing diodes, to the outputs of the measuring unit and the inputs of the fifth element OR, the output of which is connected to the input of the element NOT, the outputs of the signaling organs of the forming unit are connected to the second, third and four inputs of the second element AND, the first input of which is connected to the output of the monostable element, and the output is the first input of the third element OR, to the second the input of which is connected the output of the executive body, to the third input is the output of the first delay element, and to the fourth input through the third delay element is the output of the second delay element and the second input of the second OR element, the first input of which the second is connected to the connection point of the output of the first AND element and the first input of the fourth OR element, the output of which is connected to the fault signaling organ in the forming unit, and the output of the second OR element is connected to the first input of the actuator, and the second input of the fourth OR element is connected to the output third delay element.