Journal of Information Engineering and Applications www.iiste.org ISSN 2224-5782 (print) ISSN 2225-0506 (online) Vol.3, No.5, 2013 1 A New Technique to find the effect of Active Power Loading on Voltage Stability and Algorithm to improve Voltage Stability of Radial and Meshed Power Systems B Mahipal (corresponding author) E-mail:mahipalbhukya@gmail.com, E-mail:mahipalbhukya@yahoo.com P Venugopal Rao E-mail:pendyalavenu@yahoo.com T Swetha (E-mail:swethareddy.thuti@gmail.com) G Babu Naik (E-mail:babu.naik205@gmail.com) Ch Nareshkumar (E-mail:ch.naresh1224@gmail.com) Abstract This paper will analyze the impact of active power on voltage stability of radial and meshed systems and a new algorithm is proposed which would indicate the amount and location at which the active power is to be reduced to improve the voltage stability of entire power system or set of buses that are prone to voltage instability. A new sensitivity matrix named Active Power L-Index sensitivity matrix is been proposed. The proposed approach is simple and easy to be implemented into large power systems. The proposed approach has been applied to several Indian rural distribution networks and IEEE 14-bus test system which demonstrated applicability of the proposed approach. Index Terms- L-index matrix, Jacobian matrix, sensitivity, Active Power L-Index sensitivity matrix I. Introduction According to [1], voltage stability refers to the ability of a power system to maintain steady voltages at all buses in the system after being subjected to a disturbance from a given initial operating condition. It depends on the ability to maintain/restore equilibrium between load demand and load supply from the power system. The increased load and generation in many systems without a corresponding augmentation of the transmission infrastructure has resulted in the overloading of the transmission lines. As a result, the transmission lines operate near their steady state limits. The transmission of large amounts of power through the lines results in the large voltage drops. Sudden disturbances like line generator outage or faults in the transmission lines may result in conditions that the transmission system may not be able to supply the load demand. This could manifest as a drop in the system bus voltages which may be sudden or progressive. If the necessary remedial measures are not taken, then this may lead to the blackout or collapse of the whole system. As a result of a number of voltage stability incidents reported from various countries, there is a widespread interest in understanding, characterizing and preventing this phenomenon. This paper is essentially concerned with analyzing the effect of active power on voltage stability. II. Motivation The increasing number of power system blackouts in many countries in recent years, is a major source of concern. Power engineers are very interested in preventing blackouts and ensuring that a constant and reliable electricity supply is available to all customers. Incipient voltage instability, which may result from continues load growth or system contingencies, is essentially a local phenomenon. However, sequences of events accompanying voltage instability may have disastrous effects, including a resultant low-voltage profile in a significant area of the power network, known as the voltage collapse phenomenon. Severe instances of voltage collapse, including the August 2003 blackout in North - Eastern U.S.A, Canada, France, Japan, etc.[[2]- [4]], have highlighted the importance of constantly maintaining an acceptable level of voltage stability. The design and analysis of accurate methods to evaluate the voltage stability of a power system and predict incipient voltage instability, are therefore of special interest in the field of power system protection and planning. Static and dynamic approaches are used to analyze the problem of voltage stability. Dynamic analysis provides the most accurate indication of the time responses of the system [5]. Voltage stability indices is to predict which bus/line/path is most critical from the voltage stability perspective by assessing at the various parameters of the power system at a particular operating condition. In [7], an index called L-index is calculated