Small signal stability of a large power system as affected by new generation additions

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SMALL SIGNAL STABILITY OF A LARGE POWER SYSTEM AS AFFECTED BY NEW GENERATION ADDITIONS S. Arabi

P. Kundur, Fellow, IEEE

P. Hassink, Member, EEE

D. Matthews

Powertech Labs Inc. Surrey, British Columbia Canada V3W 7R7 Abstract: Significant new generation additions, prompted by open access, may significantly change the small signal stability characteristics of a large power system. This paper analyzes such characteristics for the 4400MW proposed generation additions in the Central and Southwest System. Non-linear time domain simulation is complemented by linear eigenvalue analysis for more insight and proper design of remedial m a u e . Power system stabilizers and a Flexible AC esrs Transmission System (FACTS) device are used to improve interarea damping. The analysis and design procedures, based on a new generation of tools, are outlined.

Central and Southwest Services Tulsa, Oklahoma U.S.A. 74121 In this paper we will show that, without any remedial measure, the damping of inter-area oscillations of the system may deteriorate significantly under the new conditions. As a result, remedial measures are proposed which include new Power System Stabilizers (PSS), as well as utilization of a Flexible AC Transmission System FACTS) device.

II. DYNAMIC STABILITY ANALYSIS A. Analysis Procedure

Keywords: Small Signal Stability, Inter-Area Oscillation, Eigenvalue Analysis, Power System Stabilizer, FACTS.

I. INTRODUCTION Open access in the North American interconnected power systems has prompted the addition of many new generating units. One example of this is the proposed generation additions in the southern region of Central Power and Light (CPL) company, known as Rio Grande Valley (RGV) and Corpus Christi (CC), which are under the administration of Central and Southwest Services (CSWS), as shown in Fig. 1. Traditionally, these regions have imported power from other regions of Electricity Reliability Council Of Texas (ERCOT) via three north-south 345 kV lines, as well as the 138 kV network. The proposed generation additions, consisting of more than 4400 MW of gas and steam turbine units with fast exciters, will result in heavy export to the rest of ERCOT. The export situation has increased the importance of series compensation on the 345 kV lines interconnecting CC and RGV. Initially RGV was under investigation for import limitations[l].

The analysis procedure is shown in Fig. 2. Note that a full system model has been used. A reduced model w s not a produced since not only can today’s tools and computing machines easily handle very large systems, but also system characteristics could readily be determined without resorting to model reduction and the associated extra effort. The latter was particularly important considering the large number of combinations for various proposed plants and other variations in the system showing different characteristics.

The Rest of ERCOT

N. Edinburg

Rio Grande Vallby Fig. 1. Proposed Generation Sights and 345 kV

Network.

0-7803-6420-11001$10.00 (c) 2000 IEEE

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