Development and application of a probabilistic simulation program for long term system planning

A probabilistic load flow simulation and contingency analysis program (PLFSCVICAP) is developed and applied to a practical long term system planning problem. The program computes the probability density functions and cumulative distribution functions of system parameters such as line flows and bus voltage magnitudes. Unlike conventional or deterministic solutions, the probabilistic solution to the power flow problem accounts for the characteristic uncertainty of power systems associated with network, nodal load and nodal generation, which are the basic input parameters to the system planning process. The increased depth of information that can be gained in the system planning process by this type of analysis which is performed within one solution is demonstrated by its application to the local Trinidad and Tobago electrical transmission system. In particular, probabilistic load flow techniques are used to address quantitatively the generation required in the island of Tobago as a transmission planning problem. It evaluates the amount of generation required to bring the voltages on the 33 kV system of the island to a level comparable to similar systems in Trinidad. Furthermore, the circuit loading on the cables linking both islands are examined for these generation amounts