This article presents an general approach to improve the power system planning, load flow pattern and stability of transmission lines using modern analysis concept. The objective is to categorize and characterize the existing system reliability concerns inherited from the adopted deterministic criteria, so that power utilities can accordingly adjust their reliability criteria to manage with real-life system uncertainties and hence to improve the overall system reliability. In the past many wide spread blackouts had occurred in interconnected power systems. Therefore it is necessary to ensure that grid should be operated economically and reliably. Contingency analysis is a well-known function in modern power system management. The aim of this analysis is to give the operator information about the static security, power flow pattern and stability. In general an outage largest capacity of one transmission line or transformer may lead to disturb the vital parameters in other lines. Modern analysis is used to calculate the violation on the network and improvement. Nuclear power plant is a base unit and best way to dispatch the power to the grid with minimum disturbance. This paper also shows the network stability, power flow management for 500MW Nuclear power plant transmission lines and connected to southern region network of India.