Characteristics and analysis of starting of large synchronous motors

Start-up of large-power synchronous motor with the 6 kV voltage source inverter and microprocessor-controlled unit for excitation supply

“…The impact of the inrush current on voltage drops in the power supply grid can be limited by starting the motor with an additional capacitor in the supply circuit [11,12,14,15]. The capacitor is the source of reactive current drawn by the motor.…”

“…In order to limit the impact of the inrush current on the power supply grid the stator starter in the form of a start-up reactor is also used [11,12,14,15,17,18]. As a result of the reactor impedance, put in series with the stator windings, the inrush current of the motor is reduced, and the motor voltage is reduced by the reactor voltage drop.…”

“…At a speed close to the synchronous speed the reactor is short-circuited. Mitigation of the start-up effects by reducing the motor supply voltage is also performed by Korndorfer autotransformer system [11,12,14,15,17]. The motor takes the inrush current proportionally to the voltage reduced by the autotransformer.…”

“…Soft start is possible in drive systems with variable frequency power supply [11][12][13][14][15][16]. Systems based on inverters supplying the stator windings with appropriate control, e.g.…”

“…Thanks to the dissemination of modular multilevel converters for medium voltage in recent years [2][3][4][5][6][7][8][9][10] it is possible to mitigate the start-up effects of large power motors [11][12][13][14][15][16].…”