POWER NETWORK SEISMIC RELIABILITY ANALYSIS BY SIMPLIFIED PARALLEL AND SERIES SYSTEMS CONCEPT

A power grid, as schematically represented in Figure 1 is mainly constituted of three main parts, namely; power plants,transmission and upper distribution substations and lines, and distribution grids.The assessment of the seismic performance of a power grid can be classif ed into three categories, as listed in bellow:1- Components performance,2- Power f ow inf uenced by components interconnectivity,3- Stability and power balance within power grid.The hierarchical structure of a power grid which is based on power delivery from higher voltage networks to lower voltagegrid, can be considered as the basis for identif cation of appropriate performance inside the power system. In Figure2 the “Distribution Network” which feeds the consumers, is fed from an upper voltage grid namely, “Upper DistributionNetwork” which is fed in turn by the “Transmission Network” and the “Power Station” as the power production source.The main idea of probabilistic modelling of power system is based on the fact that if each level of power delivery does notwork then the delivery to the main consumer will fail. This will provide a simple probabilistic parallel and series model for the problem, which seems extremely complicated. The emerging idea is well matching the idea of reliability analysis of structures using interdependent modes of failure through which, the probability of failure of a structure is suggested to be calculated using the inclusive probability of collapse in modes of failure. Since the modes of failure are not considered to be independent, the inclusive probability of failure is estimated by calculating the upper and lower limits instead of looking for exact closed form solution. However, the power network failure analysis can be much more easily performed using probabilistic modelling of simultaneous independent events that is addressed in this paper.

Keywords:

Power , Network , Reliability , Risk , System