Low Voltage Air Circuit Breaker Tripping

Hi Experts, Requesting your assistance in below problem,

Problem: Low Voltage Air Circuit Breaker Tripping (ACB-01)

Problem Description: The low voltage ACB-01 trips on the first start up of the LV Motor-01 (250 kW). On the second start the motor starts without any problem with out tripping any breakers.

Data:

Single Line Distribution as below,

ACB-01 - Feeds Power To - MCCB-01

MCCB-01 - Feeds Power To - Motor Control Centre (MCC)

MCC - Distributes Power On - MCC Busbars

MCCB-02 - Takes Power From - MCC Busbars delivers it to Motor-01 Soft Starter (through Safety Contactors)

Soft Starter - Delivers Power To - Motor-01.

ACB01 - LV ACB is 1000 Amp. rated, 3 pole, NW10H1 with Micrologic 2.0A Protection Unit, Ir = 1, tr = 4, Isd = 10.

MCCB-01 - LV MCCB is 500-1000 Amp. rated, 3 pole, NZM N4-AE1000, Set at Full Operating Range.

MCCB-02 - LV MCCB is 315-630 Amp. rated, 3 pole, NZM N3-AE630, Set at Full Operating Range.

Motor-01 - 250 kW, 415 Volts, 3 Phase, 50 Hz

Distance between ACB-01 and MCCB-01 is about 80 meters.

Distance between MCCB-02 and Motor-01 is about 50 meters.

Pls. let me know if further information required.