SU729723A1 - Remote protection device - Google Patents

Description

Union of Soviet

Socialist

Republics

USSR State Committee for Inventions and Discoveries

DESCRIPTION

Inventions

TO AUTHOR'S CERTIFICATE (61) Additional to author. certificate-wu - (22) 3 announced 01.02.77 (21) 2448594 / 24-07 with the addition of application No.— (23) Priority -

Published on April 25th, 2008. Bulletin No. 15

Date of publication of the description 30.04.80 (72) The inventors <"> 729723 g Π T B (51) M. Cl ²

H 02 N 3/40 (53) UDC 621.316.

.925 (088.8)

V.K. Vanin, G.M. Pavlov, A.I. Safonov and A.I. Tajibaev

(71) Applicant Leningrad Order of Lenin Polytechnic Institute. I.I. Kalinina

(54) REMOTE PROTECTION DEVICE

Distance protection device belongs to the field of automation of energy systems and is intended to protect power lines from all types of interphase short circuits.

Known devices for distance protection containing measuring organs, logic elements and the executive body [1], [2]. Such distance-jq protection does not satisfy the requirements of selectivity and reliability for complex damage in the power system. The use of interlocks during swings in power systems based on the use of two measuring organs with a ¹ - * sensitivity can lead to malfunction when short circuits are applied to the swings in the zone, and fixing the operation of the relay in order to reduce the effect of transient resistance can lead to excessive operation. Devices made on passive elements have low accuracy and unification of assemblies, which have large dimensions.

pain ^ in distance protection, containing measuring and starting organs, OR elements, a logic connection diagram covered by feedback, the Time element and an executive organ, and the inputs of measuring organs through an OR element and the output of a starting organ are connected to the inputs of the logic connection circuit, the output of which is through the Time element is connected to the executive o'gan [3].

The distance protection device under consideration, having a good detuning / from the load, can 'fail' if there is a significant transition resistance in the place of a short circuit. The device is also subject to rocking.

The aim of the invention is to increase reliability by eliminating false alarms when applying a short circuit Gna rocking /

This is achieved by the fact that the device for distance protection, containing measuring bodies, which are connected to the conversion by their inputs.

current and voltage drivers, and outputs through the OR element, a logic block with feedback and the element Time from the known 'distance protection devices, the closest in technical essence and the achieved result to the invention is device-30 connected to the performing organ, and the second OR element is equipped with controlled by the generator of the blocking signal, the input of which is connected through the second element OR to the additional output of the measuring organs, and the output to the second input of the logical unit, into the feedback of which en key.

In FIG. 1 is a diagram of a distance protection device; in FIG. 2 is a graph of response characteristics of measuring organs.

Distance protection device comprises converters 1 input currents and voltage measuring elements 2, 3 and 4, control unit 5 for measuring serviceability secondary circuits trans ^e Shaper voltage elements OR ^6! and 7, a logical unit 8, consisting of a comparator 9, a key 10, diodes 11-15 and resistors 16-18, a controlled blocking signal generator 19, consisting of 20. operational amplifier 20, transistor 21, diode 22, capacitors 23/24 and resistors 25, 26, element Time 27 and the executive body 28. 25

The measuring organs have the main (position 29) and additional (position 30) response characteristics in the complex plane of resistances (see Fig. 2). .thirty

Different voltages U _A, U ^, U _c and the currents _{in the} 1, _1, and ₀ 3U voltage and phase voltage windings connected in delta unlocked (when available output) are supplied to the transducers 1 the current and voltage. Here, the input quantities are converted and the voltages proportional to the phase difference ₍ currents and line voltages) are formed. Converters 1 can be intermediate transformers connected to the circuit by a measuring transformer and other matching devices. Voltages proportional to the phase current differences and linear voltages are 45 wells arrive at the inputs of the measuring organs 2, 3 and 4, having the main (29) and additional (30) response characteristics in the complex plane of resistances. outputs ie ~ 5 ° of measuring organs with the main response characteristic (29) are connected to the OR element 7, with an additional characteristic 30 to the OR element 6. 55

In case of short circuits, when the resistance at the clamps of one or several measuring organs falls into the region (29) of the complex plane of resistance, the operation signals arrive at both elements OR 60 b and 7 simultaneously. In this case, the OR element 7 generates a tripping voltage, feeds it to the input of block 8, which, changing the polarity of the voltage at the output, triggers the Vre-65 element 27. Element 27, triggering with a time delay, supplies voltage to the input of the executive body.

In the initial state, the voltage at the output of the OR element 6 is negative and the transistor 21 of the controlled blocking pulse generator is open. The potential of the inverting input of the operational amplifier 20 is equal to zero. At its non-inverting input, a negative voltage of the OR element 6 is received, which holds the operational amplifier 20 in the negative limiting mode. In this mode, the diodes 15 and 22 are closed and the blocking voltage is not supplied to the input of the comparator 9 of block 8. After the actuation signal arrives at the input of the OR element 6, the latter changes the polarity of the output voltage to positive, as a result, the transistor 21 closes, and the operational amplifier 20 goes into positive limit mode. The diodes 15 and 22 open, while the positive blocking signal is fed to the input of the comparator 9. The diode 22 opens, closes the negative feedback of the operational amplifier 20, and the capacitor 24 begins to charge. As a result of the charge of the capacitor 24, the potential of the inverting input of the operational amplifier 20 increases to the voltage at the non-inverting input, after which the operational amplifier 20 enters the negative limiting mode. Thus, the duration of the blocking signal depends on the charge time of the capacitor 24 and can be controlled by a resistor 26.

If the voltage of the element OR 6 returns to its original negative polarity before the voltage at the inverting input of the operational amplifier 20 rises. to voltage On its non-inverting terminal, the latter goes into negative limitation mode along with a change in voltage polarity at the output of the OR 6 element.

The voltage from the output of the element OR 6 is supplied, in addition, to the control input of the key 10. If the control voltage from the output of OR b is positive, then the diodes 11 and 13 are open, and 12 and 14 are closed, the transfer coefficient of the key is -. If the control voltage is negative and the condition is satisfied, then the diodes and 14 open, a'11 and 13 are closed, and the output voltage of the key becomes zero, (and ^ ₆ is the control voltage of the key supplied to the input resistor 16, is the controlled voltage of the key, supplied to the input resistor 17).

Thus, during a short circuit in region (29), the positive voltage of the OR element 6 opens the key 10 and closes, taking into account the sign of the transmission coefficient, the positive feedback of the comparator 9, which allows the comparator 9 to self-hold even when the lock signal of the controlled oscillator 19 arrives. At the same time, when the resistance value at the clamps of the measuring body exceeds the limits of characteristic (29) (for example, when the arc resistance increases in the place of a short circuit), element 8 due to iju voltage output from the switch 10 is in the active state as long as the control voltage output from the OR element 6 closes the switch 10, ie. e. until the resistance at the terminals of the measuring body will not go beyond 30 characteristics.

The delay in the generator 19 is introduced by connecting to the non-inverting input of the operational amplifier 20 of the capacitor 23. The delay time is determined by the variable resistor 25.

In the swing mode, the OR element 6 is first triggered and the controlled oscillator 19 is started, which generates a blocking voltage supplied to the input of the element 8. After a while, the OR element 7 is triggered and supplies the operating voltage to the other input of the block 8, which in this case is insufficient to operate due to the presence of a blocking voltage from the output of the generator 19. As soon as the resistance value exceeds the limits of the characteristic (30), the OR element 6 closes the generator 19 with a negative voltage. In this mode, a case is possible when, after the resistance due to swings in the characteristic region (30), a short circuit occurs in the region (29), then the control voltage of the generator 19 from the output of the OR element b will have a positive polarity, which can lead to a device failure . However, the controlled generator 19 after a time due to the charge of the capacitor 24, returns to the negative limitation mode and releases block 8, which leads to the operation of the latter due to the presence of a response voltage from the output of the OR element 7.

When damage occurs in the voltage circuits, the control unit 5 is activated, which reliably blocks the unit 8 no matter what its initial state.

The proposed device allows you to reliably rebuild from swings, including in networks with significant asymmetry in normal mode. Arrange *! The state does not lead to failure in taxation. short circuit in the swing zone and provides selective fixation of the operation of the device.

Claims (3)

The distance protection device belongs to the field of automation of energy systems and is designed to protect power lines from all types of phase-to-phase short circuits. Distance protection devices are known that contain measuring bodies, logic elements and the executive body 1, 2. Such distance protection does not satisfy the requirements of selectivity and reliability for complex damages in the power system. The use of interlocks during oscillations in power systems based on the use of two measuring organs of different sensitivity can lead to improper operation when applying short baths in the zone of the oscillator, and latching the relay to reduce the effect of transient resistance can lead to excessive actuation . The devices, made on passive elements, have low accuracy and unification of the nodes, having more weight and dimensions. Of the known distance protection devices, the closest in technical essence and attainable result to the invention is a distance protection device containing measuring and starting organs, OR elements, a logical connection circuit covered by feedback, an element of Time, and an actuator, and the inputs of measuring organs through the OR element and the output of the starting body is connected to the inputs of the logic circuit, the output of which is connected to the executive body 3 through the Time element. The considered distance protection device has a good tune-up; from the load, it can refuse, if there is a significant transient resistance in the short circuit place. The device is further susceptible to swinging. The aim of the invention is to increase reliability by eliminating false alarms when applying a swing short circuit. This is achieved by the fact that the device, the distance protection center, contains measuring organs, which, with their inputs, are connected to the transducer. the current and voltage driver, and the output through the OR element, the feedback logic unit and the Time element are connected to the operating unit, and the second OR element is equipped with a controlled blocking signal generator whose input is connected via the second OR element to the additional accelerator of the measuring bodies and the output is to the second input of the logic unit, in which feedback the key is entered. FIG. 1 shows the scheme of the distance protection device; in fig. 2 is a graph of the response characteristics of the measuring bodies. The distance protection device contains 1 input current and voltage converters, measuring units 2, 3 and 4, unit 5 for monitoring the operability of secondary circuits of the measuring voltage transformer, elements OR 6: AND 7, logic block 8, consisting of KONffiaparopa 9, the key 10, the diodes 11-15, and the resistors 16-18, the controlled oscillator 19 of the blocking signal, consisting of. operational amplifier 20, transistor 21, diode 22, capacitors 23U, 24, and resistors 25, 26, element Time 27, and actuator 28. Measuring organs have the main (position 29) and additional (position 30) response characteristics in the complex plane of the resistance (see Fig. 2). , Different voltages UA, U, U and currents 1d, 1.C, Ij ,, as well as 3Uo voltage and phase voltage of the windings / connected to an open triangle (if there is an output), are fed to the current and voltage converters 1. Here, input values are transformed and voltages are proportional to the difference of phase-phase | Currents and linear voltages. Transducers 1 can be intermediate transformers connected in circuits by a measuring transformer and other matching devices. Voltages proportional to the difference in phase currents and linear voltages are fed to the inputs of measuring bodies 2, 3, and 4, which have the main (29) and additional (30) response characteristics in the complex resistance plane. Moreover, the outputs of the measuring bodies with the main response characteristic (29) are connected to the OR element, with the additional characteristic 30 - to the OR 6 element. For short circuits x, when the resistance at the terminals of one or several measuring bodies falls into the area (29) of the complex resistance plane The triggering signals are sent to both elements OR b and 7 simultaneously. In this case, the OR 7 element generates a response voltage, supplies it to the input of block 8, which, by changing the polarity of the output voltage, triggers the element Vrem 7. Element 27, triggered with a time delay, supplies voltage to the actuator. In the initial state, the voltage at the output of the element OR 6 is negative and the transistor 21 of the controlled blocking pulse generator is open. The potential of the inverting input of the operational amplifier 20 is equal to zero. Its non-inverting input is connected to the negative voltage of the element OR 6, which holds the operational amplifier 20 in the negative limiting mode. In this mode, the diodes 15 to 22 are closed and the block voltage is not applied to the input of the comparator 9 of block 8. After the trigger signal arrives at the input of the element OR 6, the latter changes the polarity of the output voltage to positive, as a result, the transistor 21 closes and the operational amplifier 20 switches to the positive limiting mode. Diodes 15 and 22 are opened, while a positive blocking signal is fed to the input of comparator 9. Diode 22 opens, closes the negative feedback, operational amplifier 20, and capacitor 24 begins to charge. As a result of the charge of the capacitor 24, the potential of the inverting input of the operational amplifier 20 increases to the value of the voltage on the non-inverting input, after which the operational amplifier 20 switches to the negative limiting mode. Thus, the duration of the blocking signal depends on the charging time of the capacitor 24 and can be controlled by a resistor 26. If the voltage of the element OR 6 returns to the initial negative polarity earlier than the voltage on the inverting input of the operational amplifier 20 rises, until its voltage is Ma Inverting the thin side, the latter goes into a negative limiting mode along with a change in the polarity of the voltage at the output of the element OR 6. The voltage from the output of the element OR 6 also goes to the control input of the key cha 10. If the control voltage from the output of OR 6 is positive, then diodes 11 and 13 are open, and 12 and 14 are closed, the key transmission coefficient is -. If the control voltage is negative and the condition is met, the diodes 12 and 14 are opened, and 13 are closed, and the output voltage of the switch becomes zero, (- the control voltage of the switch applied to the input resistor 16, - the controlled voltage of the switch supplied to the input resistor 17). Thus, in case of a short circuit in the region (29), the positive voltage of the element OR 6 opens the key 10 and closes the positive feedback of the comparator 9, taking into account the sign of the transfer coefficient, which allows the comparator 9 to self-retain in the de-energized state even after the arrival of the signal blocking the controlled oscillator 19. At the same time, when the resistance value on the clamping element of the measuring body goes beyond the limit of the characteristic (29) (for example, when the arc resistance increases at the short circuit point), element 8 due to The voltage disconnection from the output of the switch 10 is in the actuated state until the control voltage from the output of the element OR 6 closes the switch 10, i.e., until the resistance at the terminals of the measuring element goes beyond the limits of the characteristic 30. Delay in the generator 19 introduces a connection to the non-inverting input of the operational amplifier 20 of the capacitor 23. The delay time is determined by the variable resistor 25. In the swing mode, first the element OR 6 is triggered and the controlled generator 19 is started, which is developed The blocking voltage supplied to the input of the element 8. After some time, the element OR 7 is activated and feeds to the other input of the block 8 a response voltage, which in this case is insufficient for operation due to the presence of a blocking voltage from the generator 19. As only the resistance value goes beyond the characteristics (30), the element OR b blocks the generator 19 with a negative voltage. In this mode, it is possible that after a resistance due to oscillations to the characteristic region (30), a short circuit occurs in the region (29) then the control voltage of the generator 19 from the output of the OR element b will have a positive polarity, which can lead to device failure. However, the controlled generator 19, after the time due to the charge of the capacitor 24, returns to the negative limitation mode and unlocks the block 8, which triggers the latter due to the presence of a trigger voltage from the output of the element OR 7. If a fault occurs in the voltage circuit control unit 5 triggers, which: reliably blocks unit 8, whatever its initial state. The proposed device allows to reliably build up from oscillations, including in networks with substantial asymmetry in normal mode. Device: the device does not lead to a failure when a short circuit is applied in the swing zone and provides selective fixation of the device actuation. The invention The device for distance protection, containing measuring bodies, which by their inputs are connected to a current and voltage converter, and outputs through an OR element, a logical block with feedback AND a Time element connected to an actuator, and a second OR element, t - in order to increase reliability by eliminating spurious triggers when applying a short circuit to a swing, a controlled generator of a blocking signal is inputted, the input of which is connected via the second element Or to an additional output of measuring elements, and an output - to a second input of the logical block in which the feedback of the key is inserted. Sources of information / accepted during the examination 1. Fedoseev A. M. Relein protection of electrical systems. M., Energie, 1976. 2. USSR author's certificate number 538450, cl. H 02 H 3/40 Discovery, invention. Industrial designs, trademarks, No. 45, 1976. 3.Kochetov V.V. | Levkush.A. I., Sapir E.D. One-step distance protection on semiconductor devices. Electrical station number 11, 1962, p. 75-80.