The problem of bulk power supply adequacy assessment is considered. Reliability Indices provide a means of quantifying system adequacy. However, there are numerous complex ways in which a system can fail, many of which cannot be accurately modeled with current technology. As a direct consequence, any Index calculated for design purposes must not be viewed as an absolute prediction of system adequacy. Rather, It must be considered as a relative quantity whose main utility Is In comparlson of alternate system expansion plans and In locating trouble spots within a single system. Static, dc contingency studies are useful in analyzing system Inadequacy when considering circuit thermal limits and system separations as the Important failure modes.
