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close this bookElectrical Machines - Basic vocational knowledge (Institut für Berufliche Entwicklung, 144 p.)
close this folder8. Transformer
close this folder8.3. Three-phase transformer
View the document8.3.1. Three-phase transformation with single-phase transformers
View the document8.3.2. Three-phase transformers
View the document8.3.3. Vector groups
View the document8.3.4. Application of three-phase transformers in power supply
View the document8.3.5. Parallel operation of transformers
View the document8.3.6. Technical data of customary transformers

8.3.4. Application of three-phase transformers in power supply

Figure 145 - Utilisation of transformer vector groups in power supplies

1 Power station generator, 2 Machine transformer, 3 Network transformer, 4 Distribution transformer, 5 Substation transformer

Block and machine transformers

- Block transformers along with a generator make up one unit. They establish the connection between the generator and the high-voltage side.

- Machine transformers operate in the same manner as block transformers whereby, initially, several generators work together on a bus bar.

- Preferred vector group for both transformers is Yd5.

Mains transformers

- Mains transformers function as a link between transmission networks of differing voltage planes, e.g. between the 380 kV and 220 kV mains.

- Network transformers are preferred in the Yy0 vector group.

Distribution and urban network transformers

- Distribution transformers link the transmission network to the consumer system.

- Urban network transformers are transformers whose undervoltage is less than 1 kV. Particular significance accrues to supplying the asymmetrically loaded urban network.

- The vector group Dy5 is suitable for urban network and distribution transformers.