SU729810A1 - Device for regulating voltage of power transformer - Google Patents

Description

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This invention relates to electrical engineering and is intended for automatic voltage regulation on power transformers.

A device for regulating the voltage on power transformers is known, consisting of two control paths: one to increase the voltage, the other to decrease 1.

The device includes control and monitoring units, control elements for the operability of the electric drive, a voltage limiting element at some point in the network. The device responds to changes in the network and load current. The drawback of the device is that in the event of an overcurrent, it does not block the control circuit of the switch, does not stop the switch, and does not exclude switching caused by deep voltage drops.

A device closest to the invention is known, which includes a tap changer with a drive mechanism, an automatic voltage regulator, a time relay, a memory element, and HE 2 logic elements.

In such a device, the switching process does not stop when an overcurrent occurs, and there is also no prohibition on the operation of switch 5 during a deep voltage drop.

The aim of the invention is to improve. reliability of regulation and elimination of damages in the power transformer by prohibiting the operation of the switch with unacceptable overcurrents and during deep voltage drops in the network beyond the limits of permissible values.

This is achieved by the fact that the device for regulating the voltage of a power transformer, containing its tap changer, electric drive, voltage regulator, is equipped with overcurrent relays connected to the current transformers on the supply side with a blocking element breaking the signal circuit up and down, going to the electric switch, the relay of the loop vsnani cycle connected to the signal chain up and down and through its normally open contacts to the contacts of the shaft of the switch, the maximum relay on p voltage connected.

parallel to the minimum voltage relay to the voltage transformer of the POWER output of the transformer.

FIG. 1 shows a block diagram of the proposed device; in fig. 2 is a graph of the dead zone of the automatic controller and the voltage level of the operation of the maximum and minimum voltage relays.

The output of the over-current relay 1 connected to the transformers of the current 2 is connected to the input of the locking element 3, which is connected by two terminals to the signal circuits up and down and the two outputs from the electric actuator 4 of the switch. The up and down signals are output from the automatic voltage regulator 5. The signal up through normally open contacts 6 of the relay 7 of maximum voltage and series-connected normally closed contacts 8 of the minimum voltage relay 9 is also fed to the switching cycle memory relay 10, its normal open contacts 11 connected in series with the switch shaft tracking contacts 12. A down signal is similarly supplied to the relay 13 for storing the switching cycle, its normally open contacts 14 connected in series with the contacts 15 of the follower drive shaft. The voltage at the output of the power transformer 16 is an adjustable function, supplied to a device for controlling the voltage on the power transformer via a voltage transformer 17.

The device works as follows.

The source signal of the device for regulating the voltage on the power transformer is the voltage supplied from the transformer 17 to the automatic voltage regulator 6, to the relays 7 and 9.

At a voltage level equal to the upper limit of the dead zone of the voltage regulator 5 (see Fig. 2) and voltages above this limit, the regulator 5 sends a signal down to the electric drive 4 to switch the transformer leads to an increase in voltage. At voltages equal to the insensitive zone of insensitivity and smaller values, the regulator 5 gives an upward signal to increase the voltage. The short-term control signals up and down by the controller 5 are fed to the electric drive 4 and to the relay 10 or on turnip 13 of the switching cycle. Sigt up acts on the switching cycle relay 10, which through its normally open contacts 11 and the follower follower contacts 12 of the switch shaft, which close at the beginning and open at the end of the switching, will receive a second power supply (+) for the switching time. At the same time, a second power supply through the normally open contacts 11 of the relay 10, contacts 12 and the blocking element 3 is supplied to the actuator 4. After the completion of the switching cycle, the contacts 12 open and the relay 10 returns to its original position. Similarly, the relay 13 is triggered and the start of the electric drive 4 when the signal is down. The relay 13 receives a second power through its normally open contacts 14 and contacts 15. At the same time, the second power is supplied via the locking element 3 to the electric drive 4.

When an overcurrent occurs in the power transformer 16, the maximum-current relays 1 signal to the blocking element 3 and thereby instantly turn off the power to the electric drive 4 and stop the switching. With the elimination of the supercurrent, the overcurrent relays 1 return to their original position and remove the signal from the blocking element 3. Electric drive 4 is supplied with a power supply through normally open contacts 11 of relay 10 and contacts 12 or through normally open contacts 14 of relay 13 and contact 15 in whichever signal was interrupted up or down. End of unfinished switching occurs.

With deep voltage drops, the up signal is turned off by the normally open contacts 6 of relay 7 and the switch does not move.

Claims (2)

1. A device for regulating the voltage on a power transformer, consisting of a voltage regulator with signal circuits up and down, an electrically operated switch, connected up and down in the signal circuit, a maximum and minimum voltage relay, characterized in that , in order to increase reliability, it is equipped with a maximum-current relay, a blocking element and a cycle memory relay, while the output of the maximum-current relay is connected to the input of a blocking element connected to the up and down signal circuits normally mknutye contacts Overcurrent relay electrically connected between the switch and the voltage regulator, and a relay connected to the storage loop chains signals up and down through its normally open contact to the contacts of the switch. 2. A device according to claim 1, in that it is necessary in order to prohibit the operation of the switch during deep landings of the voltage in the cross section. In the up signal circuit, normally open maximum voltage relay contacts are inserted. Sources of information taken into account in the examination 1. The author's certificate of the USSR (383193, class H 02 R 13/06, 1973. 2. Authors certificate of the USSR 259244, cl. H 02 R 13/06, 1970.