Design of LFC for a single area thermal system is investigated in this paper. Analytical design of PI controllers using D-decomposition method is presented. The proposed design guarantee pole-clustering and disturbance rejection simultaneously. Control basins realizing pole-clustering and H∞ index are constructed in the controller parameter plane. Control objectives are enforced simultaneously subjected to intersection of one-objective control basins. The study is extended to address communication time delay which in turn results in quasi- polynomial. Furthermore, governor dead-band nonlinearity is considered in the framework of D-decomposition. Simulation and calculated results are appended to prove the validity of suggested methodology.