IOSR Journal of Electrical and Electronics Engineering (IOSR-JEEE) e-ISSN: 2278-1676,p-ISSN: 2320-3331, Volume 11, Issue 2 Ver. I (Mar. – Apr. 2016), PP 54-65 www.iosrjournals.org DOI: 10.9790/1676-1102015465 www.iosrjournals.org 54 | Page Optimal Placement of AVR in RDS Using Modified Cuckoo Search Algorithm M.S.Giridhar 1 , S.Sivanagaraju 2 1 Department Of EEE, SITAMS, Chittoor, India 2 Department of EEE, J.N.T.U.College Of Engineering, Kakinada, India Abstract : Optimal Placement of Automatic Voltage Regulator (AVR) in distribution system with Modified Cuckoo search algorithm is proposed. The optimal Location of AVR’s in distribution network has been achieved using the voltage stability index values at each node and the minimum total active power loss that is obtained for a particular location of the AVR at a node. The Tap-settings of the AVR has been descided based on the optimization of objective function subjected to constraints using Modified Cuckoo Search Algorithm. The proposed method has been tested on standard 15-node, 33-node and 69-node distribution systems and the results obtained are better than the existing methods. Keywords: Automatic Voltage Regulators, Placement, Modified cuckoo search algorithm, Tap-settings I. Introduction It is the utilities responsibility to keep the customer voltage within specified tolerances; voltage regulation is an important subject in electrical distribution engineering. One of the performance criteria for a distribution system and the quality of the provided service are the maintenance of satisfactory voltage levels at the customers‟ premises. However, most equipment and appliances operate satisfactorily over some „reasonable‟ range of voltages; hence, certain tolerances are allowed at the customers‟ end. Thus, it is common practice among utilities to stay within preferred voltage levels and ranges of variations for satisfactory operation of apparatus as set by various standards [7]. One of the most important devices to be utilized for the voltage regulation is the AVRs which can be operated in manual or automatic mode. In the manual mode, the output voltage can be manually raised or lowered on the regulator‟s control board and it could be modelled as a constant ratio transformer in power flow algorithms. In the automatic mode, the regulator control mechanism adjusts the taps to assure that the voltage being monitored is within certain range. In distribution systems, voltages along the primary feeders are often controlled by voltage regulators. These regulators are generally auto-transformers with individual taps on their windings and must be incorporated into the load flow algorithms. Some distribution system power flow algorithms have been made to incorporate voltage regulator in manual or in automatic mode [5-9]. Although the Forward/ Backward sweep-based methods are mostly used for the load flow analysis of distribution systems, only a sweep-algorithm, given in [6], incorporated AVRs to the load flow analysis. In the study, AVRs are included into the forward voltage calculation of a particular forward/backward substitution method. However the authors did not model the automatic voltage regulators for the backward voltage calculation as it is not required for their particular algorithm. In distribution load flow analysis, there are number of power flow algorithms which has backward voltage calculation such as; Ratio- Flow method [2], Ladder Network theory [2, 6]. II. Problem Formulation 2.1 Optimization problem formulation with AVR To formulate optimization problem with AVR, in this chapter, three objectives namely, savings, voltage deviation (Vdev) and section current index (SCI) are considered. The details are given as follows: 2.1.1 Maximization of Savings ($) This objective is used to maximize the savings in a given system in the presence of AVR. The mathematical expression used to calculate the savings is given as follows: Max (Savings) =   (1) 8760         N K L P K VR SF LR E Where, LR P The reduction in power loss due to installation of VR = (power loss before installation of VR – Power loss after installation of VR) E K The cost of energy in Rs./kWh SF L is the Loss factor = 0.2 F L + 0.8 2 F L