A thorough and exhaustive presentation of theoretical analysis and practical techniques for the small-signal analysis and control of large modern electric power systems as well as an assessment of ...their stability and damping performance. Such systems may contain many hundreds of synchronous generators and high voltage power electronics equipment known as FACTS Devices. The book describes new techniques not only for the tuning and analysis of stabilizers for systems with many generators and FACTS Devices but also for their coordination. Of practical interest, these techniques are illustrated with relevant examples based on a multi-machine power system containing FACTS Devices for operating conditions ranging from light to peak load. By introducing new analytical concepts, using examples, and by employing production-grade software, practical insights are provided into the significance and application of various analytical techniques.
Sedimentological and palynological investigations of Great Songkhla Lakes, east coast of the Malay-Thai Peninsula, Southeast Asia, reveal sedimentary sequences rich in palynomorph assemblages ...dominated by pollen of mangroves and freshwater swamps. Compared with other regions in Southeast Asia the assemblages are of relatively low diversity. Geochronological data indicate that the Great Songkhla Lakes record one of the earliest mangrove environments in Southeast Asia (8420-8190 cal. yr BP), which are subsequently replaced by a freshwater swamp at 7880-7680 cal. yr BP owing to the decline of marine influence. Sea-level observations from Great Songkhla Lakes and other areas of the Malay-Thai Peninsula reveal an upward trend of Holocene relative sea level from a minimum of -22 m at 9700-9250 cal. yr BP to a mid-Holocene high stand of 4850-4450 cal. yr BP, which equates to a rise of c. 5.5 mm/yr. The sea-level fall from the high stand is steady at c. - 1.1 mm/yr. Geophysical modelling shows that hydroisostasy contributes a significant spatial variation to the sea-level signal between some site locations (3-4 m during the mid-Holocene), indicating that it is not correct to construct a single relative sea-level history for the Malay-Thai Peninsula.
This paper summarizes the work done by the Task Force on Assessing the Need to Include Higher Order Terms for Small-Signal (Modal) Analysis. This Task Force was created by the Power System Dynamic ...Performance Committee to investigate the need to include higher order terms for small signal (modal) analysis. The focus of the work reported here is on establishing and documenting the practical significance of these terms in stability analysis using the method of Normal Forms. Special emphasis was placed on determining and describing conditions when higher order terms need to be included to accurately describe modal interactions. Test cases were developed on a standard test system to demonstrate the application of appropriate indices to detect the occurrence of nonlinear interaction and hence the need for higher order terms in stability analyzes. The use of the higher order terms in the site selection for a damping controller is also documented.
Several methods for the design of compensation for power system stabilizers (PSSs) are used in practice. The object of this paper is to reconcile the methods and explore their relative advantages and ...disadvantages. Three methods are investigated: the GEP and the P-Vr frequency response approaches, and the method of residues. It is shown the phase response of a modified GEP transfer function (TF) agrees closely with that of the P-Vr TF, thus providing the basis for the design of a robust PSS. Residues yield only a limited number of phase angles that can be used with confidence for design purposes and are consistent with the P-Vr phase response. The remaining residues for rotor modes are affected by variability of participation factor angles and interactions from other machines. Unlike other methods, the P-Vr approach yields magnitude and phase information that simplifies the synthesis of the PSS TF and yields a robust stabilizer.
By using the concept of induced torque coefficients, a method is developed for the simultaneous coordination of power system stabilizers (PSSs) and FACTS device stabilizers (FDSs) in order to enhance ...the damping of the rotor modes of oscillation in a multimachine system. The proposed coordination scheme employs linear programming. However, because eigenanalysis using the QR algorithm is required, it is limited to systems with less than 600-700 states. A case study is given which illustrates the coordination of PSSs and FDSs in a three-area system with 29 stations, 3 SVCs and 400 states.
In this paper it is shown that interactions occur between stabilizers in multimachine power systems, the stabilizers being power system stabilizers (PSSs), FACTS device stabilizers (FDSs) or both. ...The interactions, which are identified and quantified, may enhance or degrade the damping of certain modes of rotor oscillation. In particular, interactions between PSSs are found to adversely affect the damping of inter-area modes. The analysis of interactions also provides a practical means for quantifying and assessing simultaneously the relative effectiveness of both PSSs and FDS in damping the rotor modes of oscillation. This is achieved using a stabilizer damping contribution diagram. A theoretical basis is given for the analysis of interactions and the effectiveness of stabilizers; the practical significance and applications are illustrated using a case study on a 3-area, 400 state system having 28 generator groups and a number of FDSs. For systems of more than 600-700 states the modified Arnoldi method is used for eigenanalysis-based calculations.
Using modal analysis, a new technique is described for calculating the electrical damping and synchronizing torque coefficients induced on generators through the action of FACTS stabilizers in ...multimachine power systems. At a given modal frequency and for an increment in gain of each stabilizer, it is possible to assess from an array of induced damping and synchronizing torque coefficients the effect of each stabilizer on the damping of individual generators. Furthermore, using this array, the technique is extended to calculate the contribution of each generator to the eigenvalue shift resulting from the gain increment. To illustrate the application and interpretation of the technique, stabilizers for two SVCs are designed to improve the damping of the inter-area mode in a 11 machine, 2 area power system.
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