Source station structure
Structure of Distribution Networks

Source substations provide the link between the transmission or distribution network and the MV distribution network. The main functions of source substations are :

• transforming HV or EHV voltage into MV ;

• distribution, by MV feeder, of the power available on the secondary side of power transformers ;

• setting the MT neutral system ;

• main short-circuit protection on MV networks;

• metering of incoming and outgoing energy flows;

• power factor correction using capacitors ;

• assistance to the frequency maintenance system using automatic load shedding devices;

• the transmission of tariff orders.

A distinction is made between source substations supplied with EHV (225 kV in France) by the transmission network and those supplied with HV (63 or 90 kV in...