SU1108551A1 - Device for redundant protecting of transformer with isolating switch and short-circuiting switch at high-voltage side - Google Patents

Description

The invention relates to a relay protection technique on an alternating operational current of transformers and auxiliary substations of transit power lines.

Devices for backup transformers are known in which, in the event of a short-circuit failure, an additional current-time relay is used to disconnect the circuit from the separator from the pre-charge charging capacitor PC.

This protection for backing up short circuit breakers requires an additional ON current time relay with a current relay in addition to the main transformer protection relays, while the gas protection of the transformer is not reserved.

The closest to the proposed technical entity is a device for backup transformer protection, containing coils of short-circuit switching relays connected via the contactor of the transformer’s main protectors to secondary circuits. A current transformer installed on the high voltage side of the transformer, a time-out relay for the separator, an OT-divider circuit for disconnecting a parallel short-circuit breaker in parallel. and the closing contact of the output time relay of the separator, the source of operational power 2.

However, in a known device, it is necessary to install an additional electromechanical relay that has an inadequate reliability.

The purpose of the invention is to reliably protect a transformer when a short-circuit switch fails.

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To achieve this goal, in the device for the protection of the transformer with a separator and short circuit on the high voltage side, the relay contains switching short circuit switches connected through the main transformer transformer to the secondary circuits of the current transformer installed on the high voltage side of the transformer, relay time off of the separator, the circuit off the separator of the parallel-connected, the closing of the contact circuit short circuit and the closing contact of the 1st relay time or disconnecting isolating the source of auxiliary power supply, the time switch turning off the separator vsholneno transistor in the collector circuit which included katuschka output trip relay isolating the transition base -. The emitter is bounded by a resistor, a capacitor is connected to the emitter, the other output of which is connected to the coil of the output relay of the separator and through the discharge resistor is connected to the combined anodes of the separation diodes, the leakage current of which is not less than the operating current of the output relay disconnecting the separator divided by the factor amplifying the transistor of the time relay to turn off the section in the collector of which this code relay is installed, the cathodes of the diodes are connected to the short-circuit coils, the outputs of which, under for prison to contact the main protection of the transformer, connected to the base of transistor time relay disconnecting isolator and make contact .gazovogo switch connected to a source of operative power.

The drawing shows a device for backup protection of a transformer with a separator and. short circuit on the higher side.

In the device for the protection of the transformer to the transistor power line 1, a tap transformer 2 is connected to the short circuit switch 3 via separator 4. The current protection circuit transformers 2 are connected to the main protection unit 6 and current intermediary relays consisting of supply transformers 7, smoothing condensate bridges 8, rectifier bridges 9 and coils 10 of the short circuit closing relay (actuators), connected via contacts 11 of the main terminals. The coils 10 through the separating diodes L2 include a circuit of the resistor 13 of the capacitor 14 and the shunt resistor 15, one of the outputs of which is connected to the base of the transistor 16, the emitter of which is connected to the second output of the resistor 15, and the collector to the coil of the output relay 17 Separator Through the contacts 18 of the gas protection of the transformer 2, the rectifier 19 of the operating power supply source is connected to the circuit of the resistor 13, the capacitor 14 and the shunt resistor 15. The auxiliary transformer 20 is connected via diode 21, the capacitor 22s is connected to it via short-circuit breaker 3 through the closing contacts 23 and the closing contacts 24 of the output relay. 17 to cat 25 shutdown of the separator 4. The channels 12 have no leakage currents. "Less than the output relay operates. disconnect the separator divided by. the gain of the transistor relay time off the separator. The device works: as follows. When k.z. on the transformer 2 or in its network from the current transformer 5, its main protection is triggered, acting to turn on the short-circuit switch 3 with disconnecting the transit lily 1 from the protection and disconnecting the separator 4 from the pause circuit by closing the contacts 23 of the short-circuit 3 in the coil 25 from a pre-charged capacitor 22 through a diode 21 from a motor 19 connected to the transformer; 20 auxiliary needs of transformer 2. If a transformer 2 is damaged without current, a short circuit. the gas plug 3 is also switched on from the gas detector, followed by the similar effect of the rest of the equipment. In case of failure of the short circuit 3 for any reason, the subsequent disconnection of the transformer 2 from the transit line 1 occurs due to the direct disconnecting of the separator 4 from the operation of the backup circuit of the transformer 2 protection. k.z. The contacts 11 of the main transformer 2 protection are closed. And the coils 10 receive the voltage of the transformers 7 of the current transformer 2 relay rectified by bridges 9 and the capacitor 14 is charged from the indicated voltage through the resistor 13 and the shunt resistor 15. Thanks to the resistor 13 the voltage on the capacitor 14 increases from a predetermined time to the minimum voltage of current intermediate relays. From current transformers 5 current at the output of transformers 7 after smoothing capacitors 8 and rectifying m ists 9 by closing the contacts 11 enters a pulsating rectified voltage consisting of a D.C., the latter in katush-. kakh 10 causes operation of current intermediate relays. The pulsating voltage also charges the capacitors 14 through the resistor 13 and the shunt resistor 15. When the capacitor 14 is charged, the current through the shunt resistor 15 does not change its sign, so that the potential; the base of the transistor 16 remains 14 above the potential of its emitter, therefore. the transistor 16 when charging, de condenser 14 is constantly locked. After overvoltage. the capacitor 14 of the minimum voltage of the power source in the subsequent half-cycle of alternating current stops the current through the shunt resistor 15, as a result of which the transistor 16 opens and the capacitor 14 is discharged to the output coil of the output relay 17, the contacts 24 of which close the separator disconnecting coil 25 4. The resistance value of the resistor 13 is selected from the condition of excluding: instantaneous operation of the output relay 17 in the case of a transistor 16. The capacitance of the capacitor 14 is selected from the condition of an exact reserve en WGIG to actuate the relay 17 and obtain the desired effect exposure transformers pa 2. Since the voltage level at the secondary windings of transformers 7 depends on the current of current transformer 5, therefore, a timing circuit characteristic action backup protection transformer 2-yield is dependent on the short-circuit current This characteristic is consistent with the protection characteristics of transit line 1 and is chosen more in time. If the protection of the transit line 1 is sufficiently sensitive to the short-circuit. on transformer 2 or in its network, they manage to work before the separator 4 is disconnected. If the protection of line 1 is not sensitive to the specified short-circuit, then after a set time has passed, disconnecting the separator 4 prevents the transformer 2 from failing 3. When the gas protection of the transformer 2 is triggered in the event of a 511 short circuit failure by 3 contacts 18, the capacitor charge circuit closes through a resistor 13 and a shunt 15 from a charging device 19 powered by auxiliary transformer 20. The rectified voltage of the aard device 19 likewise charges the capacitor 14 to. the moment when its voltage exceeds the minimum of the pulsating voltage of the power supply, followed by discharging the coil of the output relay 17 and similarly disconnecting the separator 4. The voltage level from the charger 19 is selected acceptable for the operation of transistor 16 with selection of the parameters of the capacitor 14, built by time from the possible maximum time of the batt shank 3. Era. The capacitor 14 charge circuit through the resistor 13 and the resistor 15 with the transistor 16 and the output relay 17 allows to reconcile the different voltages of the current: the intermediate relays with the charging voltage, the same pulsating nature of which ensures the transition of the same circuit from the charge mode in its stop mode with the accumulation of the necessary energy to trigger the output relay 17. The specified backup protection action is carried out at relatively low voltages of the secondary windings of the transformers 7, from which The well-known capacitor time relays cannot work directly with a glow-discharge thyristor, for which it is required to increase the voltage level by a factor of 3-5. Therefore, on the basis of the above combination, a maximum is achieved for the ease of execution of the short-cut failure reservation device ™. bodies of the unsolder substation of the transit power line. Such redundancy is necessary due to the fact that the failure of a short-circuit when any protection of the transformer triggers in the event of any damage entails a full failure of the transformer and substations as a whole. The noted simplicity of the execution allows to ensure everywhere the redundancy of the action of short-circuit breakers of the oustechny substations of transit power lines.

Claims (1)

(5.7) A DEVICE FOR BACKUP PROTECTION OF A TRANSFORMER WITH A SEPARATOR AND A SHORT-CIRCUIT ON THE HIGH VOLTAGE SIDE, containing short-circuit on relay coils connected through the main contactor, protecting the transformer to the secondary side of the transformer for disconnecting the current transformer from the disconnecting side of the current transformer from a separator from a parallel-connected make contact of a short-circuit and a make contact of an output switch-off time relay of a separator, source ir operational power supply, characterized in that, in order to increase the reliability of transformer protection, the separator disconnect time relay is made on a transistor, the collector circuit of which includes a coil, the output separator isolator relay, the base-emitter junction is shunted by a resistor, and a capacitor is connected to the emitter , the other output of which is connected to the coil of the output relay 'disconnector of the separator and through a discharge resistor is connected to the combined anodes of the diode separation, the leakage current of which is not less than the response current in output relay disconnected. the separator divided by the gain of the transistor of the tripping relay of the separator, in the collector of which this output relay is installed, the diode cathodes are connected to short-circuit switching coils, the terminals of which are connected to the transformer main protection contact, are connected to the base of the transistor of the separator shut-off relay and a make contact of a gas relay connected to an operational power source.