Question

2. Suppose the bus 2 load increases by 25% at constant power factor, i.e., matching the power factor of the original load. As the loading increases on the lines supplying bus

2, the system becomes less secure under line outages. A new 345 kV line is proposed to supply power to bus 2, either from bus 4 or bus 5. Assume the new line will be fully transposed on a sequence of tower structures with GMD of 8 m. (a) Determine the conductor type based on the costs shown below and the Appendix in the textbook. (b) Consider the possibility of using a bundled conductor configuration. If bundling is chosen, assume a bundle spacing of 0.4 m. Note: the cost of each additional conductor in a bundle is half the cost per km shown in the table below, i.e., the first conductor would be charged the full price, while the second, and subsequent, if any, conductor would be charged half price. (c) What MVA rating would be available for your new line? (d) Justify your choice of conductor type and bundling configuration, if any. Consider the overall costs and the performance of the new line. (e) Determine the new dispatch (Gen 1 is the most expensive unit, Gen 3 is least expensive unit) required to meet the new load. Justify your dispatch values. (f) Perform a normal case power flow study for the new 125% loading level. (g) Create a table of bus #, |V] (pu) and angle (deg). Create another table of branch flows: From, To, MW, Mvar, MVA, % loading (based on Rate A rating). (h) Perform four contingency studies for the outage of each of the four transmission lines at the new 125% loading level. (i) Create four contingency tables of bus #, |V] (pu) and angle (deg). Create four contin- gency tables of branch flows: From, To, MW, Mvar, MVA, % loading (based on Rate A rating). (i) Did you discover any overloads or low voltages (below 0.95 pu)? If any violation occured, try 1) raising the generator terminal voltage (max is 1.05 pu), or 2) adding capacitors at the load bus. Note: a 50 Mvar capacitor bank costs $750,000. (k) Compute the total cost of your substation upgrades ($2,400,000 for new 345 kV line's relays, breakers and bus work), line installation, and capacitor installation (if any).

Fig: 1