Issues related to turbine speed conversion

The speed variation rate (also known as speed irregularity) refers to the ratio of the change in the turbine’s speed from full load to no load to its rated speed. The formula for calculating it is: δ = (n1 – n2)/n × 100%, where n1 is the turbine’s speed at no load, n2 is the turbine’s speed at full load, and n is the turbine’s rated speed. Understanding of the rate of speed change: During normal operation of a turbine, when a fault occurs in the power grid or the switch at the output of the turbogenerator trips, causing the load on the turbine to drop to zero, the turbine’s speed first rises to a maximum value before falling to a stable level. This phenomenon is known as \"dynamic surge\". The maximum value of the increase in rotational speed is determined by the rate of speed change, which should generally be 4–5 %. If the rated speed of the turbine is 3000 revolutions per minute, then the dynamic rise is between 120 and 150 revolutions per minute. The greater the rate of speed change, the higher the rotational speed increases, and the greater the risk.