SU1023499A1 - Device for forming voltage between damaged phases - Google Patents

Description

The invention relates to electrical engineering and can be used in the implementation of a three-phase voltage relay or resistance relay.

A three-phase resistance relay is known, which contains a unit for generating voltage between damaged phases, in which the mini selector fl is used.

A disadvantage of this device is the relative complexity and high power consumption of the voltage sensors.

A three-phase voltage relay is known in which a block is used to form a voltage between damaged phases, containing a three-phase bridge rectifier connected to linear voltages with a ballast resistor and a relay winding, as well as a second harmonic selection and rectifying element in which the relay coil is turned on counter to the first winding 23

A disadvantage of the prior art voltage shaping device is the limited ability to obtain small errors, namely, only in a selected narrow portion of the shaping range.

The aim of the invention is to reduce the error of the device.

The goal is achieved by the fact that the device for forming a voltage between damaged phases, contains three intermediate voltage transformers, the primary windings of which are connected to the line voltages of the primary measuring voltage converter, and the secondary windings are connected to the inputs of the three-phase rectifier, a variable ballast resistor and a block for selecting and rectifying the second and other even harmonics with a variable ballast resistor, additionally introduced a block for selecting and rectifying: rpeTbevi and other odd harmonics, two series-connected capacitors and a transreactor connected at the input of the sampling and rectifying unit for the second and other even harmonics, the output of which is connected to the controlled output of the aforementioned alternating ballast resistor, to the other outputs of which are connected through the corresponding primary windings of the trerector the outputs of mitel as well as consistently

connected capacitors, to the midpoint of which and to the neutral y terminal of the secondary windings of the intermediate voltage transformers connected at the start of the intermediate voltage transformers, are connected the input of the selection and rectifying unit of the third and other odd harmonics, the output of which is connected to one of the conclusions of the aforementioned variable ballast resistor,

The drawing shows the functional diagram of the device.

The device contains a block of 1 intermediate transformers, the primary windings of which are connected to linear voltages of voltage transformers, and the secondary windings are connected in a star with a neutral terminal,

0 A three-phase bridge rectifier 2 input is connected to the secondary windings of unit 1; a variable ballast resistor 3 is connected to the output of the converter; the connection of rectifier 2

5 to resistor 3 is made through symmetrically separated primary windings of the transreactor at the input of block 5 for extracting and rectifying the second and other even harmonics; parallel to resistor 3, a chain of two series-connected capacitors 6 and 7 is connected, and between their middle output and said neutral output is connected input of sampling unit 8 and rectifying the third and other odd harmonics.

In order to obtain conditions close to optimal, for third-harmonic currents, the resistance of each

of capacitors 6, 7 should be approximately 1, (times less than the input resistance of block 8. Block 5 has a transreactor at its input, in which the same sections of the primary

windings according to included with both

of the sides of the ballast resistor 3 to make zero the amp revolutions generated by the third and each of the odd harmonics. In the transreactor k, a secondary resistor 9 is connected to the secondary winding through a full-wave rectifier, which must be designed for a short-term power consumption equal to 281 from the power of the ballast resistor 3. Unit 8 has a transformer at its input, which has a secondary winding with an average output via a two-semiconductor rectifier

Claims (1)

DEVICE FOR VOLTAGE FORMING BETWEEN DAMAGED PHASES, containing three intermediate voltage transformers, the primary windings of which are connected to the line voltage of the primary voltage measuring transducer, and the secondary windings are connected to the inputs of a three-phase rectifier, an alternating ballast resistor, and a unit for selecting and rectifying the second and other even harmonics ballast·? an output resistor, which, in order to reduce the error of the device, additionally introduces a block for selecting and rectifying the third and other odd harmonics, two series-connected capacitors and a transrector connected at the input of the block for selecting and rectifying the second and other even harmonics, the output of which is connected to the regulated output of the aforementioned variable ballast resistor, to the other conclusions of which are connected through the corresponding primary windings of the transreactor the three-phase outputs ator, and a series connection of capacitors to the middle point of which and to the neutral terminal connected to the star of the secondary windings of said intermediate trgnsformatorov voltage connected to input selection and straightening of the third unit, and other odd-harmonics, the output of which is connected to one terminal of said variable ballast.