This paper deals with design and performance analysis of automatic generation control (AGC) of a two area six unit interconnected power system. A single input Fuzzy Proportional Integral Derivative (FPID) controller is used to study the transient response of the proposed system. Area-1 consists of two thermal generating units with reheat turbines along with a diesel unit and area-2 has two thermal generating units with non-reheat turbines with a diesel unit. The gains of FPID controller is optimized by using two novel Teaching Learning Based Optimisation (TLBO) & hybrid Differential Evolution-Particle Swarm Optimization (DEPSO) technique. Step load perturbation (SLP) of 1 % is applied in area1 to study the performance of two algorithms in terms of undershoot, overshoot & settling time. Finally it is observed that the FPID controller optimised TLBO algorithm performs better than the other one.