SU1029304A1 - Device for storing phase - Google Patents

Abstract

A PHASE MEMORY DEVICE containing a series-connected oscillating circuit and a key and a threshold element connected by an input to the oscillating circuit input and an output to a control key input, characterized in that, in order to improve the accuracy of storing the phase and expand the functional capabilities of the device, it additionally introduced a phase detector, a key, a storage element, a phase-shifting unit and an adder, with one input of the phase detector connected to the working input of the phase-shifting unit, an output the key is connected to one input of the adder and another input of the phase detector, the output of which is a series of newly entered key and storage element connected by an output to the control input of a phase-shifting unit whose OUT051 is connected to another input of the adder and the output of the threshold element is also connected to control input of the newly entered key.

Description

Yu

() CO The invention relates to electrical engineering and can be used to eliminate the "dead zone over voltage of directional relay protection devices, as well as to fix the phase relationships of the parameters of the pre-emergency or short-circuit mode. Devices are known for storing the voltage phase of the previous mode, including its oscillator with adjustable oscillatory circuit, whose frequency is regulated by the frequency of the voltage of the pre-emergency mode 1. The disadvantage of these devices is the possibility of incorrect actions in the event of a frequency change in the network after a short circuit occurs. It is also known a device for storing the voltage of the preceding mode voltage, containing its doubler and frequency divider, the memory voltage frequency in which is synchronized by the current frequency 2. The disadvantages of this device are the presence of only two stable values of the phase difference of the output signal and the input current, i.e., the input voltage is generally not in-phase with the output signal, the presence of a break between the time of disappearance of the network voltage and the time of energization of the divider, which leads to a slower response, complexity performance and tuning of the electromagnetic parametric frequency divider. The closest in technical essence and attainable effect to the invention is a device for storing the phase of a short-circuit mode voltage, containing a current transformer and a voltage transformer. to the output of which is connected an oscillating circuit, three pulse shapers; a key, a threshold element and a trigger; the inputs of two pulse shapers are connected via a key to the output of the oscillating circuit, and the outputs are connected to the setup inputs of the trigger, the counting input of which is connected to the output of the third pulse shaper connected to the current transformer, the control input of the key is connected to the output of the threshold an element whose input is connected to a voltage transformer 3. A disadvantage of this device is the limited scope of its application in directional relay protection devices. When using a device in a power direction relay, it is impossible to obtain a relay triggering region as a sector with a central angle other than 180. When using a device in a resistance relay when connected to one input of a device, polarizing, and to the second start, a working emf is also impossible a relay in the Z plane, other than a circle or a straight line, on the other hand, uses the output signal of the device as a polarizing emf when it is connected to the current inputs and and provides low accuracy of storing the voltage of the voltage, since the mixing of the output signal pulses with respect to the corresponding half-waves of the input voltage can reach a quarter of the period, which causes a significant shift in the response characteristic in the z plane, and also does not allow the device to fix the pre-emergency phase the ratio of the input signals in the short circuit mode. The aim of the invention is to improve the accuracy of storing the phase and expand the functionality of the device. The goal is achieved by the fact that a phase memory device containing a series-connected oscillatory circuit and a key and a threshold element connected by an input to the oscillating circuit input and an output to the control input of the key additionally introduced a phase detector, a key, a memory element, a phase shifting the block and the adder, with one input of the phase detector plugged into the working input of the phase-shifting unit, the output of said key is connected to one input of the adder and the other input of the phase detector, n The output of which is sequentially included is the newly entered key and storage element connected by an output to the control input of the phase-shifting unit whose output is connected to another input of the adder, and the output of the threshold element is also connected to the control input of the newly entered key. FIG. 1 shows a functional diagram of the device; in fig. 2 - functional, on the circuit of the resistance relay using a device for storing the phase. The device contains an oscillating circuit 1, a threshold element 2, one key 3, an adder 4, a phase detector 5, another key 6, a storage element 7, a phase-shifting unit 8. The input of the oscillating circuit 1 is connected to the input of the threshold element 2 and is one input of the device storing the phase, the other input of which is the input of the phase shifting unit 8 connected to another input of the phase detector 5. The output of the oscillating circuit 1 is connected through one switch 3 to one input of the adder 4 and one input of the phase detector 5, the output of which About through another key 6 is connected to the storage element 7, the output of which is connected to the control code of the phase-shifting unit 8 connected to another input of the adder 4. The output of the threshold element 2 is connected to the control inputs 3 and 6 of the keys. The first output of the device is the output of the adder 4, the second is the output of the storage element 7. It is convenient to consider the operation of the device using the example of its use in the relay circuit

resistance in order to eliminate the "dead zone by voltage." The resistance relay circuit comprises a device for storing the phases 9, a unit 10 for forming the compared EMF, a unit 11 for phase comparison. The inputs of the oscillatory circuit 1 and the threshold element 2 are connected to the first output of the block 10, the second output of which is connected to the second input of the block 11 and the input of the phase-shifting block 8. The output of the adder 4 is connected to the first input of the block 11. The voltage of the one input of the block 10 , and to another - the current of the protected object. At the first output of the GO unit, a polarizing emf is generated, supplied to the inputs of the oscillatory circuit 1 and threshold element 2, and the second unit 10 forms a working emf Ep supplied to the second input of the unit 11, another input of the phase detector 5 and the input of the phase-shifting unit 8 In the general case, if the response characteristic of the resistance relay in the plane r passes through the origin, then ...

. E, Kt y,.

Ep K4U-f K4 IB before the emergency mode at the inputs of the unit 10. The normal voltage and load current of the protected object are applied. Since the value of TU is determined by the input voltage, in the pre-emergency mode, the TU has a nominal value exceeding the threshold of triggering of the threshold element 2, and a control inputs of keys 3 and 6 are given an opening signal. In this case, the signal from the output of the oscillatory circuit 1, determined by the value and phase E, is fed to the inputs of the summatar 4 and the phase detector 5. Thus, in the pre-emergency mode, the inputs of the phase detector 5 receive signals whose phase difference is Duralian phase difference between E ,, and Ep, and at its output a signal proportional to Dc is formed (which, through the public key 6, goes to the storage element 7 and then to the control input of the phase-shifting unit 8, at the output of which a signal is generated that is phase-shifted by naphthol (- DQ relative to the input c heading Ep and, therefore, in-phase with Un. Thus, the inputs of adder 4 receive in-phase E signals, so the output of adder 4 also produces an in-phase E, signal E0. Because the resistance Zp - at the output of the resistance relay is outside the range of operation in the Z plane and the phase ratio of the signals at the input of block 11 are equal to the phase relations E and E, then at the output of block 11 there is no signal.

In the established mode of remote short circuit in the zone of action of the resistance relay, the operation of the device is similar, however, the phase relationship between E and Ep in this case causes the resistance relay to operate.

In the steady-state short-circuit short-circuit voltage U and the associated value of Hz are reduced to the value of the lower threshold of the threshold element 2, the output of which produces a signal that closes the keys 3 and 6. The signals at the input of the adder 4 and at the input memory element 7 are zero. The phase of the signal at the output of the phase-shifting unit 8 is determined by the phase Op, and the value of the signal at its control input received from the storage element 7, the output signal of which is generated in the first 1-1.5 periods after the occurrence of a short circuit due to the delay to turn off of the threshold element 2. At the same time, after the input voltage disappears, and consequently, the E signal at the output of the oscillatory circuit 1 represents a fading free oscillations slice with a frequency close to the network frequency and the cola due to the setting atelnogo circuit 1 and a phase corresponding to the phase E ,, prefault mode. Since during the delay for switching off the threshold element 2, the keys 3 and 6 are opened by a signal from the output of the threshold element 2, then the inputs of the adder 4 and the phase detector .5 receive a common-mode signal Ец. Since the other input of the phase detector 5 receives the signal E, the output signal of the phase detector 5, prpr1 is the ionic phase difference D between E ,, and Yor in near short circuit mode, through the open key 6 enters the input of the storage element 7 and is fixed after the switching off by the threshold element 2 of the key 6. Thus, in the steady-state short-circuit mode, at the output of the phase-shifting unit 8, a signal is generated that is shifted to that phase relative to E by an angle. (), equal to the phase difference between ETJ and Yp, therefore, in-phase Y-P. . Since the signal at one input of the adder 4 is absent, the output signal of the adder 4 is also in phase. Ep. In this case, the phase relations between E and Op cause the triggering of block 11. The time required to establish the desired phase EF depends on the constant time of the phase detector 5, the recording circuit of the storage element 7 and the phase-shifting block 8 and should be less than the delay to turn off the threshold element 2 and the protection time delay generally.

The device can also be used in resistance relays and devices for fixing a place of damage with detuning from the load current. When the short circuits are removed and there is a load connected between the protection installation location and the short circuit location, the resistance at the protection terminals in general does not equal the line resistance from the installation location of the protection to the point of damage due to

shunting effect of load resistance, for detuning from which it is necessary to know both its value and nature, which can be determined with a sufficient degree of accuracy by fixing the phase difference between the voltage and current of the protected object in the pre-emergency mode. To use the device in order to determine and fix the nature of the load, it is necessary to send a signal to the first input of the device that is in phase with the current of the object to be protected, for example, from the output of a current transformer, and to the second input of the device to give a signal in phase with the voltage of the object to be protected, for example from the output of a voltage transformer.

In this case, the threshold element 2 should be made with an inverse output, i.e., when the input signal of the threshold element 2 drops below a predetermined level, a signal is formed at the input of the threshold element 2, which opens the keys 3 and 6, and the time constant of the recording circuit of the storage element 7 is selected much longer than the delay time of the threshold element 2.

In the pre-emergency mode, a signal is supplied to the first input of the device, the phase and value of which is determined by the current-load mode. The threshold for triggering the threshold element 2 is chosen such that in this mode, at the output of threshold element 2, a signal is generated that opens the keys 3 and 6. The operation of the device is similar to that described above in the pre-emergency mode. When a short circuit occurs, the input current becomes greater than the threshold of the threshold element 2, the output of which produces a signal that closes the keys 3 and 6. The phase of the input current changes, which causes a change in the signal at the output of the detector 5. However, the recording circuit of the storage element 7 is open 6, therefore, the signal at the output of the storage element is proportional to the phase difference between the current and voltage in the pre-emergency mode. Otherwise, the operation of the device is similar to that described above in the mode of an installed remote short circuit. The signals at the output of the phase-shifting unit 8 and the adder 4 in-phase pre-emergency current.

Claims (1)

DEVICE FOR STORING A PHASE, containing a series-connected oscillatory circuit and a key and a threshold element connected by an input to the input of the oscillating circuit, and an output - to the control input of the key, characterized in that, in order to improve the accuracy of memorizing the phase and expand the functionality of the device into it additionally introduced a phase detector, a key, a storage element, a phase-shifting unit and an adder, while one input of the phase detector is connected to the working input of the phase-shifting unit, the output mentioning The internal key is connected to one input of the adder and another input of the phase detector, at the output of which the newly introduced key and a storage element are connected in series, connected to the control input of the phase-shifting unit, the output of which is connected to another input of the adder, and the output of the threshold element is also connected to the control input newly entered key.