Problem Statement A generating station located in Larkana is supplying power to a load center (with four types of loads)

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Problem Statement A Generating Station Located In Larkana Is Supplying Power To A Load Center With Four Types Of Loads 1 (237.53 KiB) Viewed 10 times

Problem Statement A generating station located in Larkana is supplying power to a load center (with four types of loads) in the Sukkur region through a transmission line (line impedance: 0.15+ j0.32 02/km). A pair of three-phase transformers (0.8/11 kV and 11/0.8 kV) are utilized at either end to reduce line losses. The three-phase transformer at each end is designed using a bank of three single phase transformers. A short circuit test has been executed at HV side of any single-phase transformer to determine the following values of transformer impedances: Equivalent series resistance: 3.2 (series elements referred to the HV side) Equivalent series reactance: 5.70 (series elements referred to the HV side) ● ● As for the load center with multiple types of loads: ● The first load is a flour milling company, which absorbs an average active power of 270 kW, and the company has maintained the power factor to 0.82 Lagging. The time of operation for this company is 08-00 am to 4-00 pm. The second load is a small textile mill, working from 10-00 am to 06-00 pm while maintaining the power factor of 0.86 lagging and consuming 150 kVAS. On the other hand, the third load consists of a group of laundry shops (where clothes irons are used for pressing clothes on large scale), absorbing real power of 50 kW and it is operational from 12-00 pm to 08-00 pm. Similarly, the last load is a toy manufacturing unit, consuming the apparent power of 260 kVA while maintaining a power factor of 0.85 lagging for a time duration of 8 hours per day, from 02-00 pm to 10-00 pm. The electrical frequency of all the loads is fixed to be 50 Hertz. ● ● You are hired as a design engineer to propose The VA ratings of the transformers. The three-phase transformer connections in terms of Wye and Delta. Also, justify the type of transformer that you are selecting for the said scenario; it may be an autotransformer or an ordinary transformer keeping in view the financial perspective of your selection along with technical ones. While designing the transformer, also take the following factors into account: ● Total demand for the load Overall weather of the region Height relative to sea level Note: National Electric Code or NFPA 70 standards states: transformer kilovolt-ampere should be derated by 8% for each 10°C above 40°C (when air-cooled for a dry-type transformer) and by 0.3% for every 330 feet over 3,300 feet altitude). Deliverables The following deliverables are required which should be presented in your report: 1. Deliverable 1 a. To propose adequate power ratings for all the transformers used in the system. b. To calculate the voltage regulation of the transformers at different points of time in a day. c. To calculate the line losses of the transmission system at different points of time in a day. d. To calculate the real, reactive, and apparent power supplied by the generator at different points of time in a day.