SU903845A1 - Stabilized power supply source for self-contained relay protection devices - Google Patents

Description

(54) STABILIZED POWER SUPPLY UNIT FOR AUTONOMOUS RELAY PROTECTION DEVICES

one

The invention relates to relay protection and is designed to power stand-alone devices, in particular, a power direction relay, a frequency relay, a current relay and a voltage.

A stabilized power supply unit is known, which contains an intermediate current transformer (PTT) and an intermediate voltage transformer (PTN), the secondary windings of which are connected to a storage capacitor through two diode rectifiers. The specified power supply unit provides only the relatively low output voltage stability that the phenomenon of ferroresonance is capable of giving.

Also known is a key power supply unit containing a PTT, the secondary winding of which is connected via a diode rectifier to a storage capacitor, a zener diode and a thyristor 2.

The disadvantage of this power supply unit is that the thyristor turned on at the output of the rectifying bridge flows around the full-wave rectifier current, and as the current rises, the unit will fail to work as soon as the thyristor does not

it has time to turn off by the time of the rise of the current of the next half-wave to the level of its holding current.

Also known is a stabilized power supply unit containing PTT and PTN, the secondary windings of which through a diode rectifier are specifically connected to a storage capacitor, and a ballast capacitor is connected in series with the primary winding PNT and two thyristors, control electrodes of which are connected through the anode of the Zener diode, the cathode of which is connected to the positive clamp of the storage capacitor 3.

Claims (3)

This unit works reliably with a phase shift between voltage and current other than 180 °, however, if the voltage and current are out of phase or close to it, it may be that the thyristor held in the on state by one of the electrical quantities it does not have time to turn off after passing it through a zero value and will be kept in the on state by another value. Under such conditions, the storage capacitor will cease to receive a charge, i.e. the pi.ani unit will fail. The purpose of the invention is to increase the reliability of the stabilized power supply. The goal is achieved by the fact that the power supply unit containing an intermediate current transformer and an intermediate voltage transformer, the secondary windings of which are connected via a diode rectifier to a storage capacitor, and in series with the primary winding of the intermediate voltage transformer is connected to a ballast capacitor, and two thyristors controlled electrodes of which are connected via an isolating diode to the anode of the zener diode, the cathode of which is connected to the positive terminal of the storage capacitor, newly introduced two thyristors, the control electrodes of which are connected to the anode of the mentioned Zener diode through additional decoupling diodes, the first two thyristors are connected counter-parallel to the secondary winding of the intermediate current transformer, and the second newly introduced thyristors are parallel to the secondary winding of the intermediate voltage transformer. In the proposed stabilized power supply, the thyristors flow around with a half-wave current regardless of the phase shift between current and voltage, which ensures their reliable locking at the end of each half-period at any desired multiplicity of input current. All thyristors are controlled with just one Zener diode. A schematic of the proposed stabilized power supply unit is shown in the drawing. The stabilized power supply unit consists of an intermediate current transformer 1, an intermediate voltage transformer 2, in series with which a ballast capacitor 3, thyristors 4-7, decoupling diodes 8-I, diode rectifiers 12 and 13, the zener diode 14 and the storage capacitor 15. If only one of the quantities is fed to the input of the unit, for example, current i, the storage capacitor 15 will be periodically charged from the current circuit including intermediate current transformer 1, thyristors 4 and 5, diodes 8 and 9, and rectifier 12, and when the voltage on its plates reaches a value sufficient for breaking Zener diode 14 and turning on thyristor 4 (5), the secondary winding of transformer 1 is shunted until the end of the half period . The control current enters the thyristor 4 (5 through open diodes of rectifier 12, punched Zener diode 14 and diode 8 (9). After switching on the thyristor 4 (5), the rectifier turns off and the control current turns off. If the input voltage of the unit is U In a similar way, the thyristors 6 (7) are periodically turned on through the open diodes of the rectifier 13, the zener diode 14 and the diodes 10 (11). The capacitor 3 serves to limit the current through the transformer 2 and the thyristors b and 7. When leading to the block inputs of both values and and i the storage capacitor 15 gets en Because of the state of the thyristors of each of these circuits does not depend on the state of the other circuit, the proposed unit does not have the disadvantage of the known device. Thus, the proposed invention improves the reliability of the power supply unit by eliminating the likelihood of loss of performance with increasing input values, and a positive effect is achieved without increasing the number of threshold elements. Claims of the Invention A stabilized power supply unit for stand-alone relay protection devices comprising an intermediate current transformer and an intermediate voltage transformer, the secondary windings of which are connected to a storage capacitor through diode rectifiers, and two thyristors in series with the primary winding of the intermediate voltage transformer, and two thyristors, control electrodes of which are connected through the decoupling diodes to the anode of the stabilitron, the cathode of which is connected to the positive With the purpose of increasing the reliability, two thyristor Si are reintroduced into it, the control electrodes of which are connected to the anode of the above-mentioned zener diode through additional decoupling diodes, the first two thyristors are connected counter-parallel to the secondary winding the intermediate current transformer, and the second newly introduced thyristors are counter-parallel to the secondary winding of the intermediate voltage transformer. Sources of information taken into account during the examination 1. USSR author's certificate No. 652546, cl. H 02 H 7/00, 1979. 2.Little D.W., Potochney G.J., Pinkley R.A. A time overcurreut relay with solid-state cirenitry. - IEEE P.owr engineering society Conterence papers, 1975, p. 1-7, 3. USSR author's certificate for application No. 2828494 / 24-07, cl. H 02 H 3/38, 1979. / J // H 74 / cf H1V S -0 / J ti