Estimation of frequency control performance using probability distribution of load change

Abstract

In North American utilities, control area performance of interconnected power systems is assessed by the reliability standards imposed by the North American Electric Reliability Corporation (NERC). NERC standards on control area performance define two indices known as Control Performance Standards 1 and 2 (CPS1 and CPS2) to evaluate control area performance in normal interconnected power system operation. Out of the two indices, CPS1 evaluates the performance of a control area with respect to control of interconnection frequency and tie-line power flows. This thesis proposes a novel method to approximately estimate CPS1 for a two area power system using the probability distribution of load change. The proposed method of estimating CPS1 is validated against the time domain simulation method using a simple two-area test system. In the validation process, it is shown that the proposed method could approximately forecast CPS1 within 5% accuracy. The forecasted CPS1 value could then be used by a control area to design its future control strategies to be in compliance with NERC criteria at the minimum cost. These control actions include, but not limited to tuning governors, reducing non-confirming loads, ensuring adequate operating and spinning reserves etc.