Hand Book Illumination

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This is a good book on lighting and illumination with basics.
    Lesson1 Introduction Version 2 EE IIT, Kharagpur 2  Instructional Objectives ã   State the need for Illumination. ã   Define good Illumination. ã   State what comprises an electric utility? ã   List standard voltage levels. ã   State need for high voltages for transmission. Course Overview ã   Radiation and colour. ã   Eye and vision. ã   Different entities of illuminating systems. ã   Light sources: daylight, incandescent, electric discharge, fluorescent, arc lamps andlasers. ã   Luminaries, wiring, switching and control circuits. ã   Laws of illumination; illumination from point, line and surface sources. ã   Photometry and spectrophotometry, photocells. ã   Environment and glare. ã   General illumination design. ã   Interior lighting – industrial, residential, office departmental stores, indoor stadium,theater and hospitals. ã   Exterior lighting – flood, street, aviation and transport lighting, lighting for displays andsignaling – neon sign’s, LED – LCD displays beacons and lighting for surveillance. ã   Utility services for large building/office complex and layout of different meters and protection units. ã   Different type of loads and their individual protection. ã   Selection of cable/wire sizes; potential sources of fire hazards and precautions. ã   Emergency supply-stand by and UPS. ã   A specific design problem on this aspect. Introduction Light by definition connotes Electromagnetic radiation that has a wavelength in the range fromabout 4,000 (violet) to about 7,700 (red) angstroms and may be perceived by the normal unaidedhuman eye. In fact in the prehistoric days, all human activities were coordinated with Sunriseand Sunset. Today, in principle activities are carried out round the clock. All this is made possible because of Artificial Lighting systems. The lighting systems comprise of a sourceemploying any physical phenomenon among Incandescence, Electrolumniescence or Flourescence. Some control scheme and a Luminaire. In fact all this has lead to a class of  professionals called Lighting Engineers or Illumination Engineers. Unlike other group of  professionals they need to be adept at not only at exact sciences of Maths, Physics, Chemistry; but be wary of Physiology and Psychology of users (like a medical professional); have goodaesthetic sense and economically utilize resources (like an architect video Fig. 1). Efficacy of these systems is talked in terms of Illuminance per Watt of energy consumed. Efforts are on toreduce energy conmsumption yet have efficient Illumination to enhance productivity. Need lessVersion 2 EE IIT, Kharagpur 3  to mention that all these sources employ electrical energy. Trend these days is to employ,modern electronic controls together with energy efficient lamps. These aspects are borne inmind, right from the planning stage of a building. As electrical energy is being used for the purpose, it becomes important for Illuminating Engineer to come up with an integrated systemfor the complete electrical system of a building. UsefulnesstoHumanityMathChemistryPhysicsEconomicsArt(Aesthetic point)PhysiologyPsychologyMedicineIlluminationEngineeringArchitecture Fig. 1 Professions-sciences-usefulness relationship.1. Necessity of Illumination Humans depend on Light for all activities. Light is a natural phenomenon, very vital for existence, which is taken for granted. In fact, Life involves day night cycles beginning withsunrise and ending with sunset. Pre-historic man had activities limited only to day time. Artificiallight enables extended activity period employing in an planned optimized manner, minimizingthe resources.Vision is the most important sense accounting for 80% information acquisition for humans.Information may be acquired through sun/moon light (direct/ reflected) or by using artificial light(closest to natural light). Before we go any further, it is worth looking at Teichmuller’s definitionfor lighting. “We say the lighting is good, when our eyes can clearly and pleasantly perceive thethings around us”. Therefore Artificial light should be Functional and pleasant bothPhysiologically and Psychologically. This is often achieved employing multiple sources. It must be borne in mind that the sources should be economic and energy efficient. As all of us areaware, all sources today employ electrical energy.Electrical energy is supplied as a.c. (alternating current) or d.c. (direct current). Usually electric power supply is a.c. in nature, either single phase or three phase. It must be borne that closecircuit is a must for current flow. As it is well known losses exist in all electrical circuits or lines.Version 2 EE IIT, Kharagpur 4   By definition Losses = i 2 R, where i = line current in A,R = line resistance in Ω longer the line higher the resistance and higher level.Thus for a particular power level current decreases with increase in voltage i.e. p = v x i (instantaneous power). Hence, losses are minimized by supplying at higher voltages. Normal sources of electrical energy are either hydro or thermal (coal based or nuclear). Usually power stations are located very far from load centers. Therefore, power is transmitted at highvoltages.It may be mentioned that, standard levels of power transmission being 132, 220, 340, 400, 735,765, 1000 kV ac. HVDC or High Voltage Direct Current transmission is also fast catching up asan alternative.Fig.2 shows a single line diagram of a typical Power System with all its components.X’mission line132/220/400 kV400V ~ Generator11/33 kV Fig. 2 Typical Power System Distribution line66/33/11kV We know that load is always unbalanced for a practical 3-phase system. Fig 3 shows thewaveform of a 400 V 50 Hz a.c supply. Here, 400 V, 3 phase, 50 Hz connotes that supply isthree phase a.c. at a frequency of 50 Hz with a line to line voltage of 400 V rms, which translatesto 564 V peak value.564V1 t msms2 Fig. 3 Waveform of 400V, 50Hz a.c supply In view of the fact that artificial Illumination employs electrical energy in a.c form, next, weaddress each fundamentals of a.c generation.Version 2 EE IIT, Kharagpur 5
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