Complex sentence: On the day of accident turbine 2 worked as the plants power otput regulator and due to this its output power changed al the time and it worked lot of time in band II regime which is accompanied with pulsation and strokes of water flow.
Split into simpler sentences: On the day of accident turbine 2 worked as the plants power output regulator and due to this, its output power changed constantly. The turbine often operated in band II regime which is accompanied with pulsation and strokes of water flow.