A control system, apparatus, and method to control load sharing of multiple generator sets of a power supply system are described. Load transient set points to add an individual generator set can include a transient percentage threshold to characterize load transients as a load transient, a transient count threshold, and a transient count time period during which a detected number of load transients is compared with the transient count threshold. A controller can determine whether to add the individual generator set based on whether the detected number of load transients is equal to the transient count threshold within the transient count time period and control addition of the individual generator set responsive to the detected number of load transients equaling the transient count threshold.