1. Consider a three-phase power system with one-line diagram shown in Figure 1. The three-phase trans- former between CBs 1 and 2 (CB: circuit breaker) nameplate ratings are listed: 5MVA, 13.8A-138.0YkV, the transformer reactance X?1 = 3.80 (viewed from low voltage side 13.8kV, resistance is negligible). The impedance of the transmission line between CBs 3 and 4 is ZL1 = (10+j100). -(50 pts) (a) Pick up SB = 100MVA for the entire three-phase system, and rated voltage VB = 138.0kV, calculate the per-unit line L1 and transformer impedance values. (b) If an SLG fault occurs at the midpoint of the line (L2) between CBs 5 and 6, which breaker(s) should operate? If the CB 5 or CB 6 does not operate, which breaker(s) will provide the backup protection? (c) List the operating CB(s) for different zones, which are listed in Figure 2. (d) If the second generator is connected at bus 3, the system (generators, buses, and transmission lines) is protected by overcurrent relays R1 to R12. Assuming the directional overcurrent relays are used for three transmission lines, what is the remote backup relay(s) for R7? And why? G Generator mm www Transformer - GSU Bus 1 depending on which breakfas Bus 3 Transmission line L1 Shunt Reactor L3 Shunt Capacitor Figure 1: A three-phase power system. Bus 2 Distribution Transformer Feeder
Problem 1: A 100 ft long pipe transporting steam through the PSU campus is made of AISI 316 stainless steel. The pipe is an 8"Schedule 40 pipe (note that 8" is the nominal dimension but you need to look up the actual dimensions of an 8" Schedule 40pipe!). The pipe transports steam through an open space of air at T,=20°C and a heat transfer coefficient of 10 W/m²K. The steady-state inside wall temperature of the steam pipe is at 140°C. Note that you can look up thermal conductivity and other thermophysical properties in Appendix A of the course textbook,or through other reputable sources. (a) Determine the rate of heat loss from the steam pipe if it DOES NOT have insulation. Ans: 25 kW (b) If we want to reduce the heat loss to 10% of its value from part (a), what thickness of calcium silicate pipe insulation should be added to the outside of the pipe? You can assume that the inside surface temperature of the steam pipe remains at 140°C, as well as the outside air conditions. You may need to use an iterative solver (such as Exce?'s Goal Seek, in Data->What If Analysis->Goal Seek; or perhaps Matlab,or even a guess-and-check method).
The wedge shown in the figure below is used to level the member.The coefficient of static friction between the wedge and the two surfaces of contact Determine the horizontal force P that must be applied to begin to push the wedge forward. Neglect the weight of the wedge.
2. A cam, with a minimum radius of 25 mm, rotating clockwise at a uniform speed is to be designed to give a roller follower, at the end of a valve rod, motion described below : 1. To raise the valve through 50 mm during 120° rotation of the cam; 2. To keep the valve fully raised through next 30°B 3. To lower the valve during next 120°; and 4. To keep the valve closed during rest of the revolution i.e. 90° ;
12-6 In a storm, waves may have a height of 12 m and a period of 15 s. Compare the power per meter of wave front to the average values shown in Figure 12.1.
Part I: Initiative Proposal Write a 350-to 525-word summary of the sustainability initiative you want to promote at the health care setting you selected. Your proposal should: Create a clear vision or mission statement that defines the scope of the initiative and would generate buy-in. Define what outcomes you expect to achieve over time. Be specific with what you can realistically deliver.
7. Answer the following questions. [10 pt] ?. A solid sphere of mass 2 kg and radius 30 cm rolls down an incline without slipping. If the incline is 5 m high, how fast is the ball going at the bottom? b. A 500 g hoop with diameter 1.2 m is rolled down the same hill. If it too rolls without slipping, how fast is the hoop going at the bottom of the hill? c.Show that if the moment of inertia is given by I = CMR² , where c is a factor dependent on the shape of the object, that the acceleration down the incline is given by a=\left(\frac{1}{1+c}\right) g \sin \theta d. List two additional shapes with similarly formatted moments of inertia that could be rolled down the same hill. Rank all four (your two shapes, the sphere, and the hoop) in order of smallest to largest acceleration.
2) [6 points] Calculate the annual savings in gasoline and Ib CO, that would result from switching from a 19 mpg truck to a 34 mpg car. Assume the vehicle is driven 9,500 miles per year. (Note: the combustion of 7.5 gal of gasoline generates 150 lb of CO2).
