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EE587_Ch3_sp10

# EE587_Ch3_sp10 - EE 587 Electric Power...

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Unformatted text preview: EE 587 Electric Power Distribution/Utilization Dr. M. Safiuddin, Research Professor Department of Electrical Engineering University at Buffalo [State University of New York] EE 587_Sp10 1 EE 587 Electric Power Distribution/Utilization TEXT BOOK: ANSI/IEEE -Std. 141-1993 [ The Red Book]; Published by Institute of Electrical & Electronics Engineers, New York. Lecture Topics: 1. 2. 3. System Protection I Introduction, System Planning & Design Course orientation, Overview, Definitions, Planning guide for the supply and distribution system [Ch 2] Voltage Considerations Voltage control, Voltage selection, Effects of voltage variations on low and medium voltage equipment, voltage quality considerations.[Ch. 3] Sources of fault currents, Fundamentals of fault current calculations, Restraints of simplified calculations, Example case studies. [Ch. 4] EE 587_Sp10 2 1 Chapter 3. Voltage considerations ! " \$ ( # %& ! *+ , ' ! ! ) ! EE 587_Sp10 3 EE 587_Sp10 4 2 EE 587_Sp10 5 EE 587_Sp10 6 3 ! "# % \$ Range A (V) & Range B (V) 127 13 114 4 110 6 (4 †) 104 (106†) Maximum allowable voltage Voltage drop allowance for primary distribution line Minimum primary service voltage Voltage drop allowance for distribution transformer Minimum secondary service voltage Voltage drop allowance for plant wiring Minimum utilization voltage *For utilization voltage of 120-600 V. 126 (125*) 9 117 3 114 6 (4 †) 108 (110†) † For building wiring circuits supplying lighting equipment. EE 587_Sp10 7 EE 587_Sp10 8 4 EE 587_Sp10 9 '" Standard Nominal System Voltages 120 120/240 208Y/120 240/120 240 480Y/277 480 600 ! " 1. Low Voltages Associated nonstandard System Voltages 110, 115, 125 110/220, 115/230, 125/250 216Y/125 230, 250 460Y/265 440 550, 575 EE 587_Sp10 10 5 Table 3-3 Nominal System Voltages- Medium Voltages Standard Nominal System Voltages 2400 4160Y/2400 4160 4800 6900 8320Y/4800 12 000Y/6930 12 470Y/7200 13 200Y/7620 13 200 13 800Y/7970 13 800 20 780Y/12 000 22 860Y/13 200 23 000 24 940Y/14 400 34 500Y/19 920 34 500 46 000 69 000 2200, 2300 Associated nonstandard System Voltages 4000 4600 6600, 7200 11 000, 11 500 14 400 33 000 44 000 66 000 EE 587_Sp10 11 '" ! " ( )* ( Standard Nominal System Voltages 115 000 138 000 161 000 230 000 Associated nonstandard System Voltages 110 000, 120 000 132 000 154 000 220 000 Standard Nominal System Voltages 345 000 500 000 765 000 Associated nonstandard System Voltages EE 587_Sp10 12 6 #! Te = 3 × 2π ns V2 R1 + ' R2 s 2 × + X eq 2 ' R2 s ,& I2 = V2 R' R1 + 2 s 2 + X eq 2 2 Is = (R + R ) + X 1 '2 2 V2 eq 2 EE 587_Sp10 13 EE 587_Sp10 14 7 EE 587_Sp10 15 +,- " ! " ! . / & ! 0 * & *1 ' *** & & ' & ' & ! (* ! EE 587_Sp10 16 8 +,- " The light output and life of incandescent filament lamps are critically affected by the impressed voltage. The variation of life and light output with voltage is given in table 39. The figures for 125 V and 130 V lamps are also included because these ratings are useful in signs and other locations where long life is more important than light output. EE 587_Sp10 17 Applied Voltage vs Percentage Life 1000 800 P ercent Life 600 400 200 0 0 50 100 150 Applied Voltage 120V Lamp Rating % life 125V Lamp Rating % life 130V Lamp Rating % life EE 587_Sp10 18 9 Applied Voltage vs Percent Light 140 120 P ercent Light 100 80 60 40 20 0 0 50 100 150 Applied Voltage 120V Lamp Rating % light 125V Lamp Rating % light 130V Lamp Rating % light EE 587_Sp10 19 • Fluorescent Tubes consist of gas discharge tube with a pair of electrodes - one at each end and are sealed along with a drop of mercury and some inert gases. • The inside of the tube is coated with phosphor. EE 587_Sp10 20 10 Fig 9: Detailed Components of Electronic Ballast EE 587_Sp10 21 Table 6: Power & Current consumed at Different Voltage Levels Voltage Hours of Operation 100 hrs 200 hrs 0.368A 0.336A 0.308A 0.285A 0.265A 0.294A 36.8 W 36.9 W 36.9 W 36.9 W 37.1 W 35.28W 300 hrs 0.366 A 0.335 A 0.307 A 0.283 A 0.263 A 0.289 A 36.6 W 36.8 W 36.8 W 36.8W 36.9 W 34.68W 100 VDC 110 VDC 120 VDC 130 VDC 140 VDC 120 VAC 0.370A 0.337A 0.309A 0.287A 0.268A 0.301 A 37 W 37.07 W 37.08 W 37.31 W 37.52 W 36.12 W EE 587_Sp10 22 11 Hours of Operation vs. Current 0.4 0.35 0.3 Current (A) 0.25 0.2 0.15 0.1 0.05 0 0 50 100 150 200 250 300 350 Hours of Operation 100 110 120 130 140 Fig 11: Current Response to aging EE 587_Sp10 23 Hours of operation vs. Power Input 37.6 P ower Input (W ) 37.4 37.2 37 36.8 36.6 36.4 0 50 100 150 Hours of Operation 100 200 300 EE 587_Sp10 24 12 Current Response to Aging (AC volts) 0.302 0.3 C urrent (A ) 0.298 0.296 0.294 0.292 0.29 0.288 0 50 100 150 200 250 300 350 Hours of Operation 120 EE 587_Sp10 25 Hours of Operation vs. Power Input 36.2 36 35.8 35.6 35.4 35.2 35 34.8 34.6 0 50 100 150 200 250 300 350 Hours of Operation Po w e r In p u t (W ) 120 EE 587_Sp10 26 13 , 2 - %3 , 4 .56 2 7 8, 9 4 5# + 4 • • • • • Compact fluorescent lamps (CFLs) are smaller versions of standard fluorescent lamps. They consume between 5 to 40 watts and have a brightness and color rendition that is comparable to incandescent lights. They last up to 10 times longer Use about 1/4 the energy. Produce 90% less heat, while producing more light per watt. EE 587_Sp10 27 , 2 - %2 9 9 4 8 2 . , .5 EE 587_Sp10 28 14 Cost Savings of 9 W CFL over a 40 W Incandescent Lamp Lamp Type 40 W Incandescent Hours of Operation / day Cost of Lamp Lamp Life Cost per watt Savings per year Estimated payoff period Light Output 4 hours 0.50 1000 hrs 10 cents N.A. N.A. 425 lumens 9 W Compact Fluorescent 4 hours 3.65 6000 hrs 10 cents \$ 4.37 10 months 390 lumens EE 587_Sp10 29 Current and light output response to variations in voltage and aging Voltage Hours Of Operation 100 hrs 200 hrs 64 mA 62 mA 60 mA 58 mA 71 mA 12 ft-candles 14 ft-candles 16 ft-candles 18 ft-candles 19 ft-candles 66 mA 64 mA 62 mA 60 mA 73 mA 300 hrs 10 ft-candles 12 ft-candles 14 ft-candles 16 ft-candles 17 ft-candles 100 VDC 110 VDC 120 VDC 130 VDC 120 VAC 62 mA 60 mA 58 mA 56 mA 69 mA 14 ft-candles 16 ft-candles 18 ft-candles 20 ft-candles 21 ft-candles EE 587_Sp10 30 15 Hours of Operation vs. Current Consumed 68 Current Consumed (mA) 66 64 62 60 58 56 54 0 100 200 Hours of Operation 300 400 100 110 120 130 EE 587_Sp10 31 Hours of Operation vs. Light output 25 L ight output (ft-candles) 20 15 10 5 0 0 100 200 Hours of Operation 300 400 100 110 120 130 EE 587_Sp10 32 16 Hours of Operation vs. Current consumed 73.5 73 72.5 72 71.5 71 70.5 70 69.5 69 68.5 0 50 100 150 200 250 300 350 Hours of Operation Current C onsumed (mA) 120 EE 587_Sp10 33 Hours of Operation vs. Light Output 25 Light Output (ft-candles ) 20 15 120 10 5 0 0 50 100 150 200 250 300 350 Hours of Operation EE 587_Sp10 34 17 • Making bulbs last longer often does not pay. • Conversion process from DC to AC and back AC to DC result in unnecessary power losses. • The performance of lighting system both incandescent and fluorescent in terms of light output and life expectancy is roughly the same in both AC and DC. EE 587_Sp10 35 * ! ! " EE 587_Sp10 36 18 Based on 30 ft/Volt drop for a fully loaded conductor EE 587_Sp10 37 \$ \$ " . ! " Preferred horsepower limits Low-voltage motors No min.- 15 hp max. No min.- 200 hp max. 1hp min.- 1000 hp max. Medium-voltage motors 50 hp min.- 6000 hp max. 100 hp min.- 7500 hp max. 250 hp min.- no max. 400 hp min.- no max. 1500 hp min- no max. Motor nameplate voltage 115 230 460 and 575 2300 4000 4500 6000 13200 EE 587_Sp10 38 19 \$* \$ 0 Motor Type Load / " Percent Added Heating 0 8 25 0 8 25 Insulation System Class A A A B B B Temp. rise (oC) 60 65 75 80 86.4 100 Percent Voltage Unbalance 0 2 3.5 0 2 3.5 U-frame Rated Rated Rated Rated Rated Rated T-frame EE 587_Sp10 39 EE 587_Sp10 40 20 EE 587_Sp10 41 EE 587_Sp10 42 21 : EE 587_Sp10 43 EE 587_Sp10 44 22 EE 587_Sp10 45 3.11.6 effect of motor starting on generators EE 587_Sp10 46 23 Figure 3-14 shows the behavior of the voltage of a generator when an induction motor is started. Starting a synchronous motor has a similar effect up to the time of pull-in torque. The case used for this illustration utilizes a full-voltage starting device, and the full-voltage motor starting load in kilovolt-amperes is about 100% of the generator rating. It is assumed for curves A and B that the generator is provided with an automatic voltage regulator. EE 587_Sp10 47 NOTES: (1) The scale of motor horsepower is based on the starting current being equal to approximately 5.5 times normal. (2) If there is no initial load, the voltage regulator will restore voltage to 100% after dip to values given by curves. (3) Initial load, if any, is assumed to be of constant current type. (4) Generator characteristics are assumed to be as follows: (a) generators rated 1000 kVA or less: performance factor k=10; transient reactance Xd`=25%; synchronous reactance Xd=120%. (b) generators rated above 1000 kVA: characteristics for 3600 rpm turbine generators. EE 587_Sp10 48 24 ...
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