Abstract— Solar/diesel hybrid rooftop applications are finding rapid use all over India. Rooftop photovoltaic (PV) systems can be hugely advantageous for commercial as well as domestic institutions which use inverters, diesel generators and other auxiliary sources to diminish energy costs and also guarantee power continuity in the event of faults/ outages. An existing educational institution in Delhi taken for case study, is proposed to have Rooftop Solar Panels. This paper aims to analyze the power flow of an 11.0 kV low voltage distribution system using the Newton-Raphson (NR)method .The case study also includes short circuit analysis for the proposed system in Electrical Transient Analyzer Program (ETAP) Software. Keywords— Electrical Transient Analyzer Program (ETAP), Newton Raphson(NR),Photovoltaic(PV),Short Circuit Analysis(SC). I. INTRODUCTION OOFTOP solar projects are a known phenomenon nowadays. These PV systems offer a great opportunity for institutions, industries, and all other buildings already using UPS, inverters, batteries and diesel generators to reduce energy costs and to ensure power continuity in the event of grid unavailability. Scientifically, the combination of one infinite resource (renewable energy) and a finite resource (non renewable energy) can produce beneficial results, depending upon the feasibility. Rooftop solar projects still have not been economically viable and face issues such as ownership disputes. As per the findings of International Energy Agency, the major portion of energy production in member countries of Organization for Economic Cooperation and Development (OECD) - about 60%, is still dependent on the combustible fuels whereas the contribution from Renewable Energy Sources (RES) has significantly increased from less than 2% in the year 2006 to more than 5% by the end of the year 2011.[1]Governments world-wide have tried to tackle this problem through providing subsidies to either the developers – who would then set up installations on rooftops; or to the citizens – who can then invest in the huge upfront costs required to procure and install a rooftop solar system.[2] The SPV Hybrid systems are designed to operate with both grid and diesel generators in conjunction with the deep cycle lead acid solar battery bank. The system is used to supplement the load & can be configured as either a battery Kusum Tharani is working in the Electrical and Electronics Engineering Department in Bharati Vidyapeeth’s College Of Engineering, affiliated with GGSIP University, Delhi(email-kusum.tharani@bharatividyapeeth.edu). Prof.Ratna Dahiya is with the Electrical Engineering Department, National Institute of Technology, Kurukshetra(email- ratna_dahiya@yahoo.co.in) charger or inverter. The inverter operates in parallel with either the grid supply or the diesel generator with active power to the load. II. INSTALLATION AND BASIC COMPONENTS OF ROOFTOP PV SYSTEM PV solar power systems are very simple electric power- generating plants comprising the following basic components:  PV panels that transform sunlight (photons) into Direct Current(DC) electricity  A racking system to hold the panels to the roof and exposes the panels to the sun at an advantageous angle  Inverters to transform the DC electricity into AC electricity  Wiring for connection  Storage battery (In the case of grid fed power plant, big-size battery is not necessary to store and use that power after sunset.) While installing large scale projects help in achieving the capacity addition targets faster, small scale rooftop PV systems have some very obvious advantages. [3]  No additional land that could be used for other purposes is required for rooftop PV systems.  Huge savings in the Transmission and Distribution losses.  Diesel consumption offset – In India, rampant power cuts are a norm and the scheduled outages can be as high as 16 hours a day in some parts of the country. During the outages, industries, commercial establishments and residential consumers tend to use diesel generators. Power from diesel generators is not only expensive, but also leads to pollution.  Solar PV rooftop systems can also reduce the reliance of the power grid.  Local employment generation Solar projects gained lot of momentum since 2012 in India. In July 2012, the total installed capacity of solar power generation projects crossed 1 GW, mainly propelled by the state of Gujarat’s solar policy(more than 700 MW) Rooftop Solar PV Plant for a Low-Voltage Distribution Network Kusum Tharani, and Ratna Dahiya R 3rd International Conference on Power, Control and VLSI Engineering (ICPCVE'2014) Jan. 5-6, 2014 Dubai (UAE) 17