Power system reliability importance measures

Abstract

The objective of the paper is to develop a method which can rank the power generation sources by the new reliability importance measures. The ranking may represent the standpoint for the power system operator to reward the power plants which more contribute to reliable power supply and at the same time to penalize the power plants which do not contribute enough. The new importance measures base on the classic loss of load probability evaluation, which is a standardized method for assessing reserve power in order to assure certain level of desired power system reliability and which can be a method for compare power systems reliability. The features of the importance measures as defined within the probabilistic safety assessment of nuclear power plants are used in relation with the loss of load probability calculations. The straightforward algorithm for loss of load probability is considered for smaller power systems and the recursive algorithm is considered for larger power system, where the number of states considered increases over the capacity of the straightforward algorithm. The results show the ranking of power plants as generating units in the power system from a viewpoint of the reliability increase and from the viewpoint of the reliability decrease of the power system, both as a function of reliability of the specific power generating unit. The results depend mostly on the nominal capacity of the power generating unit under investigation, on the forced outage rate of this unit, on the parameters controlling the timely power of this generating unit within the power system and on the load curve of the power system, which can be expressed in terms of daily load diagram or in terms of yearly load diagram depending on the definition of the time period of interest