Characteristics of STAR-STAR connection

• In star-star connection, similar ends join together to form a neutral or star point.
• If neutral is taken outside then the system will be three phase, 4 wire system.
• In star-star connection line voltage is given by V_L = V_P√3.
• In star-star connection line current and phase current are equal  I_L = I_P.
• Line voltages are 120 degree apart.
• Line voltages are 120 degree ahead w.r.t phase voltage.
• Zero sequence current can be avoided due to neutral.
• As phase voltage is less so less number of turns are required and hence less insulation is required.
• Due to high currents winding must have large cross sectional area.
• This connection is economical for high voltage transformers and is seldom used.