A practical approach on optimal RTU placement in power distribution systems incorporating fuzzy sets theory A.A. Razi Kazemi ⇑ , P. Dehghanian Department of Electrical Engineering, Sharif University of Technology, Tehran, Iran article info Article history: Received 12 September 2011 Accepted 5 December 2011 Available online 16 January 2012 Keywords: Remote terminal units (RTUs) Placement Analytical hierarchical process (AHP) Power distribution system Reliability cost/worth abstract Supervisory control and data acquisition (SCADA) infrastructures have so far been brought into the huge amount of focus since the need for a more reliable power system accosting with the catastrophic events of interruptions has been raised. Hence, benefiting from an automation technology which can remotely monitor and coordinate commands to enable immediate response and switching are obviously inevitable. This paper outlines an implementable method in response to the goal of placement of remote terminal units (RTUs) which are in charge for data acquisition and control in a power distribution system. In this light, a new practical methodology based on the robust decision making (DM) method, analytical hierar- chical process (AHP), is proposed to simply and at the same time profoundly exploit some practical aspects which have not been considered before in the cases of placements. The proposed method inves- tigates both qualitative and quantitative aspects interrelated with the placement problem. Fuzzy sets are then involved to overcome the existent uncertainty and judgment vagueness. The optimum number of RTUs to be located in the previous-step obtained candidates is determined through reliability cost/worth analysis. Having the belief practically implemented on a real distribution test feeder of Iran’s power grid, the efficacy and accuracy of the proposed methodology are satisfactorily confirmed. Ó 2011 Elsevier Ltd. All rights reserved. 1. Introduction The era in which large number of interruptions and their long durations are of little criticality for both domestic and industrial sections is almost over and thereby power continuity accompanied by its quality has so far concentrated vast research focuses. The increasing number of outages in addition to their long durations makes a great number of manpower be enrolled to resolve the problem and consequently less time for equipment services will survived. With the postponed equipment services, equipments fail- ure rates would steeply increase and consequently, high statistics of interruptions will be reported by then. In non-automated power distribution girds, after each interruption, a lot of time will be spent to find the fault location and its isolation from the rest of the network. This time may further increase to several hours in large scale networks or because of some operation limitations such as traffic and population crowds; however, in today’s industries, power outages even for a few seconds will last some irreparable technical and economical damages. Therefore, the need for super- visory control and data acquisitions of power distribution systems and also benefiting from an automation system that can remotely monitor and coordinate commands to enable immediate response and switching seems indisputable [1,2]. Power distribution automation means the effective perfor- mance of all the operators and operation centers by a control cen- ter and a main computer system via several terminals located in remote critical areas. As a consequence, fault occurrence is going to be detected much faster, the troubleshooting time will decrease to a minimum, and the remaining grid is promptly isolated [1]. RTUs in a SCADA system gather information and are responsible for sending/receiving and executing the commands issued from the control center. Practically approached, having faced with the huge number of substations in a real distribution power system, the com- plex and computationally demanding nature of the problem leaves the way to the optimal placement candidate faraway. Hence, find- ing the appropriate numbers and locations of RTUs is exceedingly intricate in nowadays complicated power distribution systems. Some efforts have been conducted in this area. Of the past pub- lished papers in this context are some which attacked the problem in the sub-transmission power systems. They all concentrate more on investigating the effects of automation on power system protec- tion, reliability, and operation where power system observability seems to be the focal point. Ref. [2] did a great deal in RTU placement using a new method to place a minimum set of RTUs. This paper undertakes system observability, absence of critical measurements, 0142-0615/$ - see front matter Ó 2011 Elsevier Ltd. All rights reserved. doi:10.1016/j.ijepes.2011.12.001 ⇑ Corresponding author. Address: Room 114, Mosallanezhad dormitory of Sharif University of Technology, Teymuri Sq., Tehran 1459818444, Iran. Tel.: +98 9122804631. E-mail addresses: A.Razi.Kazemi@gmail.com (A.A. Razi Kazemi), Payman.Dehghanian@ gmail.com (P. Dehghanian). Electrical Power and Energy Systems 37 (2012) 31–42 Contents lists available at SciVerse ScienceDirect Electrical Power and Energy Systems journal homepage: www.elsevier.com/locate/ijepes