37 Load modeling Techniques in Voltage Stability Studies R.Suganya * , M.Thenmozhi ** * Department of Electrical and Electronics Engineering, I.F.E.T College of Engineering, Villupuram -605108,suganjothi@gmail.com, ** Department of Electrical and Electronics Engineering, I.F.E.T College of Engineering, Villupuram -605108 mozhi.pse@gmail.com ABSTRACT Voltage stability continues to be a limiting phenomenon in many power systems world-wide. When combined with a continual growth in load, the lack of sufficient and optimally located generation together with the failure to build new transmission facilities has lead many systems to be vulnerable to situations of uncontrollable system voltages. In its most severe form, voltage stability can result in localized or even cascading system blackouts. To deal with serious issue, many utilities have mandated the study of voltage stability as a normal component in system planning and operation. While acceptable methods of voltage stability analysis have emerged in recent years and comprehensive tools have been developed, the issue of load modeling remains a challenge. This paper involves modeling the different types of loads in order to predict the maximum deliverable power. Index Terms- Load modeling, Voltage Stability, PSAT 1. INTRODUCTION For many power systems, voltage stability assessment has become one of the most important types of analysis performed as a part of system planning, operational planning, and real time operations. Voltage stability is defined as the ability of a power system to maintain steady acceptable voltages at all buses in the system under normal operating conditions and after being subjected to a disturbance. Instability can occur in the form of a progressive fall of voltage of some buses[1]. The main factor causing voltage instability is the inability of the power system to maintain a proper balance of reactive power throughout the systems and therefore it is often associated with systems inadequate or poorly located generating sources and insufficient transmission facilities. Loads are represented in large scale computer simulations, represent the aggregation of hundreds or thousands of individual component devices such as motors, lighting, and electrical appliances. International Journal of Research in Electrical & Electronics Engineering Volume 2, Issue 1, January-March, 2014, pp. 37-46, © IASTER 2014 www.iaster.com, ISSN Online: 2347-5439, Print: 2348-0025