7.2　Main Electrical Connection

7.2　Main Electrical Connection

7.2.1　The main electric connection shall be determined according to the hydropower station′s role in the electrical power system，hydraulic energy parameters of the hydropower station，layout of the project and equipment features，and shall meet the requirements for reliable operation，simple connection，easy operation and maintenance，and economic project investment，etc.If the hydropower station is constructed by stages，the connection shall be convenient for transition.

7.2.2　For the connections on the step-up voltage side of hydropower station，the methods of single-bus or sectional single-bus connection，line-transformer unit connection，bridge connection or angular connection should be adopted.

7.2.3　For the connections on the generator voltage side，the methods of unit connection or multi-generatortransformer unit connection，single bus or sectional single bus connection may be adopted.(https://www.daowen.com)

7.2.4　The main transformer of hydropower station shall be three-phase，and its capacity may be selected based on the capacity of the generator connected with it.If the nearby load is connected to the generator voltage bus，the minimum nearby load may be deducted in the selection of the main transformer capacity.If there is penetrating power passing through the main transformer，the maximum penetrating power shall also be added to the capacity of the main transformer.

7.2.5　If the units are switched on and off frequently or it is required to use the power grid to supply power to the plant，a circuit breaker shall be installed at the outlet of the unit-connection generator.