SU1476567A1 - Device for restoring electric supply to electric power consumer in incomplete-phase - Google Patents

Abstract

The invention relates to electrical engineering, in particular, to devices for restoring power supply to consumers in the event of a power failure in a three-phase electrical network. The goal is to increase the reliability of power supply. The device contains an electrical network from which consumers are powered. When a non-full-phase mode occurs in the network, a voltage relay connected to the phases of the electrical network reacts due to a single phase break, and the damaged phase of the network is turned off. The disconnecting contact of the voltage relay closes, the coil of which is turned on for the faulty phase, and the opening contact for one of the unaffected phases. A current relay operates, the coil of which is connected between the common point of the closing contacts of the voltage relay and ground, while the closing contacts of the voltage relay and its coils are connected to the opposite phases. The closing contacts of the current relay are included in the power supply circuit of the DC motor and the three phases of the asynchronous motor connected to the unit, while the asynchronous motor is connected to the terminals of the consumers in parallel with the full-phase network. Work in the generator mode, it balances the voltage at the terminals of consumers. 1 il.

Description

ten

15

20

25

567

dd her

thirty

35

40

50

0

five

0

five

d e

0

five

0

0

in the generator mode, it is connected to the mains and provides voltage balancing in the incomplete-phase electrical network. This ensures the normal start-up and operation of three-phase single-phase consumers 8.

The voltage level of the phase damage depends on the ratio of the power of the three-phase asynchronous motor 16 and the consumer 8. For normal operation of consumers, the voltage level in the damaged phase can be set to -10% of nominal. To ensure this level, if consumers are three-phase asynchronous electric motors that rotate the fans, the power of the asynchronous electric motor is chosen 0.2-0.25 of the total power of the electric motors of the fans. If consumers 8 are three-phase asynchronous motors, in which the torque on the shaft is equal to the torque of the working machine, the power of the synchronous motor is chosen equal to 0.5-0.7 of the total capacity of the electric motors. If there is another load in the structure of consumers, besides electric motors, it is necessary to ensure the work of consumers in the intermittent mode, taking into account technological necessity.

Experimental studies conducted in the laboratory have shown that it is better to connect all phases of a three-phase asynchronous electric motor 16 to the electrical network, since this ensures synchronism with the electrical network and there is no need for special devices to control the DC motor. Three-phase rectifier 13 provides operation in non-phase mode with one or two phases missing.

Claims (1)

Invention Formula A device for restoring power supply to consumers with electrical energy in non-phase-phase modes of operation of the supply network, comprising a phase fault isolation unit, which is made in the form of three minimum voltage relays connected to each phase network up to their closure contactor, i. i / which are included in series in The power supply circuit of the consumers, and the opening contacts are connected to each phase of the power supply network and combined into one point, characterized in that, in order to improve the reliability of the power supply, a three-phase rectifier is additionally added to it, the DC motor is a three-phase asynchronous motor, intermediate relay, while the intermediate relay coil is connected between the common disconnecting point of the relay minimum five voltage and ground, the windings of the undervoltage relay and the corresponding opening contacts are connected to opposite phases, the three-phase rectifier is connected to the supply circuit to the closing contacts of the undervoltage relay, and its output through the first closing contact of the intermediate relay is connected to the motor supply circuit direct current, three-phase asynchronous motor connected to the supply circuit through the second closing contacts of the intermediate relay after the closing contacts of the undervoltage relay. 1 Editor A. Makovska Compiled by N. Panteleeva .Techred L.Oliynyk Proofreader M. Pojo Order 2165/54 Circulation 608 VNIIPI State Committee for Inventions and Discoveries at the State Committee on Science and Technology of the USSR 113035, Moscow, Zh-35, Raushsk nab. 4/5 Subscription