Estimation of frequency control performance using probability distribution of load change

Abstract

This paper proposes a novel method to estimate Control Performance Standard 1 (CPS1) using the probability distribution of area load change. The proposed method predicts an estimation of the CPS1 value for the future, which could be used in deciding operating strategies to achieve a target CPS1 value. NERC standards on frequency control performance define two indices known as Control Performance Standards 1 and 2 (CPS1 and CPS2). This paper focuses on CPS1, which is used to evaluate control area performance in normal interconnected power system operation. The most straightforward method of estimating CPS1 is to perform a time domain simulation provided that the area load forecast is available. However, if only the probability distribution of load change is available, then a random load curve must be generated to use in time domain simulation. This paper proposes a simple technique to estimate CPS1 directly from the probability distribution of load change without performing a time domain simulation which significantly reduces computing time. Hence predictive evaluation of CPS1 value is a novel concept which could be very useful in practice. A two-area test system is used to demonstrate the accuracy of the proposed method against the time domain simulation method.