The generatioin and transmission capacities have not kept pace, In general, with the load-demand necessitating the generators to be loaded to their maximum capacity have not kept pace, the generators to e loadede to their maximum capacity most of the time. Due to insufficient spinning reserves, andy emergency outage of major generating unit of hte tripping of a tie-line on fault leads to frequency sinking, over-loading and cascade tripping of generators. The low frequency condition is generally accom-panied by low voltage unless elaborate arrangements like field forcing, etc, are provided in the generators. This is further aggravated due to the lowering of transient stablity limits particularly where long transmission lines are involved. The system is likely to separate out at an undesirable, into two segments with large disproportionality in the the generation and load-demand. Frequent operation of hte system at low frequency also results in cumulative damage to the generating units, particularly to the low pressure-stage baldes of steam turbines and in their ultimate mechanical breakdown.