CHAPTER ONE
1.0    INTRODUCTION
    Electricity is the principal force that powers modern society. It lights buildings and streets, runs computers and telephones, drives trains and subways and operates all variety of motors and machines (“Powering a Generation”, 2014).
    It is important to recognize that electricity is not mined or harvested, it must be manufactured. Since it is not easily stored in quantity, it must be manufactured at the time of demand. Electricity is a form of energy, but not an energy source. Different generating plants harness different energy sources to make electrical power. Some of these sources are thermal plants, kinetic plants, geothermal power and solar photovoltaics (“Generating Electricity”, n.d.).
    Since, the demand for electricity in this area of the world is alarming, there is the need for the production or generation of constant electricity, due to the epileptic condition of electricity in the country. This gives rise to the design and construction of a 5KVA pure sine wave Uninterruptible Power Supply(UPS). UPS is an acronym which stands for Uninterruptible Power Supply. Sudden interruption of power sometimes throws the nation as a whole into darkness for hours. The effect is that, the nation as a whole experiences a great harvoc that also affects social economic life of the nation. Due to all these problems caused by the sudden interruption of power supply, it became a great concern to engineers and technicians to find solution to the problem since they are the world problem solver who convert dreams to reality. Hence, the need for an Hybrid Uninterruptible Power Supply (HUPS). As the name implies, a UPS maintains continuous supply of electricity to our system when there is power failure. It also ensures that there is no damage to the electronic equipment or home appliances when there is power surge. All functions performed by UPS earn it to be defined as a device that serves as an alternative source of power when there is power failure. It is majorly used as a backup for computer systems and some household appliances. The uninterruptible power supply finds its use in hospitals, schools, offices and also in various houses (“Uses of UPS”, 2011).
    The hybrid Uninterruptible Power Supply (UPS) has more than one means of charging the battery. Apart from charging the battery through mains, it is also incorporated with solar panel (photovoltaic cell) hence the name hybrid. The solar panel (PVC) is able to charge the battery with the help of charge controller which regulates voltages from the solar panel to the require voltage needed to charge a 24V dc battery.
    The UPS are of two types, the rotary and static type. The rotary UPS uses an alternating current motor (AC motor), and alternating current generator (AC generator), these two are coupled together for the power needed by the AC load. The AC motor aids the continuous driving of the AC generators so as to give continuous power supply when its need arises. The static type UPS has no moving parts, it is highly efficient and provides continuous power supply at the time primary AC power fails.
    UPS is classified as ON-LINE and OFF-LINE according to their voltage and frequency fluctuations. The ON-LINE UPS is constantly ON. It is required where there is a wide range variation in voltage and frequency that are needed to be stabilized.
    The OFF-LINE UPS takes its supply from the mains and is passed through a stabilizer at the same time it is charging the battery. It is also refers to as standby UPS. Off-line UPS is used as back-up in areas where fluctuation of voltage and frequency is less (“Classification of UPS”, 2012).
    Sunlight, a natural form of energy generates DC current to power solar panel by both infrared and ultraviolet ray in the electromagnetic field spectral as it radiates on to the solar panel.
    However, UPS deals with its use with respect to how it is being trapped to generate DC current for human use, the solar energy could be trapped into a panel already designed to attract electron being ionized from their ground orbit and then flow into the UPS that convert it into AC current by inversion. The energy generated in this form is being stored in batteries in form of charges so that it can be used at a later time (“Photovoltaic Cell”, 2016).
    Solar power is the conversion of sunlight into DC current. Sunlight can be converted directly into usable energy using photovoltaic cell (PVC) or indirectly with Concentrated Solar Panels (CSP) which normally focuses the suns energy. A solar cell or photovoltaic cell (PVC) is a device that converts sunlight into DC current using the photo electric effect (“Solar Energy”, 1999).