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Recently, the evaluation of control performances of interconnected power systems has become an important issue with respect to individual load frequency controls. Several performance measures are in practical use such as Area Control Error (ACE), Mutual Aid Criterion (MAC), and Control Performance Standard (CPS). Area Requirement (AR) is an alternative expression for ACE, where AR=-ACE. However, the characteristics of these indices have not been sufficiently studied as far as the authors know. In particular, this is the case for their dynamic behavior against random load disturbances. This paper investigates the performance index, AR, through analysis of two-area systems. Major dynamic elements of interconnected systems affecting the frequency are taken into account to investigate responses of the system against load disturbances. The analysis shows that, when new systems are interconnected, the smaller system tends to require more effort of control against load disturbances to keep the same value of the performance indices. © 2005 Wiley Periodicals, Inc. Electr Eng Jpn, 154(1): 20–28, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20233 [ABSTRACT FROM AUTHOR]

This paper proposes a new method for obtaining controlling unstable equilibrium point (CUEP) for transient stability analysis in electric power systems. A minimization problem is formulated to attain CUEP by applying the critical trajectory (CTrj) method to the boundary controlling unstable equilibrium point (BCU) method. CTrj method is a unique approach proposed by the authors to obtain critical condition for transient stability problem. The Proposed method simultaneously computes a trajectory on the stability boundary starting from the exit point reaching CUEP. The effectiveness of the method is demonstrated through simulations for various systems. [ABSTRACT FROM PUBLISHER]

SUMMARY In this paper, we propose three applications to quantitatively evaluate N-1 security with increased uncertainties. By using a robust dynamic security region (RDS), which is based on the concept of robust power system security (RS), the key region for judging the security and a new evaluation index for quantitative analysis, we can evaluate power system security as follows. (1) The calculation of the RDS at the time of yearly peak load demand can be recognized as the benchmark for the N-1 security at present, and this method can be applied to the future power system with increased renewable energy resources (RES) such as PV. (2) We show the yearly declining trend for N-1 security resulting from increased PV deployment year by year. (3) We calculate the necessary amount of additional power supply capacity, including conventional electric power generators or storage batteries, needed for maintaining the N-1 security at the present level. The effectiveness of the proposed method is demonstrated through simulations using a model system with three machines. [ABSTRACT FROM AUTHOR]