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  3. please answer both parts of part d...

Question: please answer both parts of part d...

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Please answer BOTH parts of part D

A utility company plans to install capacitor banks in a newly built 230 kV substation. According to load flow and dynamic stability studies, the power system needs about 160 Mvar of additional reactive power to accommodate system changes (such as new lines and loads). Due to the design of the substation and reactive power requirement, it is decided to split the reactive power demand into two stages. Thus there will be two three-phase capacitor banks, each rated at 80 Mvar. The following data is available, The system three-phase short circuit capacity at the substation is 11,500 MVA. e Each phase of the three-phase 80 Mvar capacitor bank is contructed using the fol- lowing arrangement (see Fig. 5.5): There are 6 parallel units in each series group.

190 ELECTRICAL TRANSHENT PHE NOME NA There are 8 series groups Each capacitor umit is rated at 800 kvar and 19,92 kV (see Table Capacitor banks are configured as grounded wye. substation. Note that Rank #2 is energized only when Bank #lis air mik along is 120 feet away from Barkお1, and the bus bar inductance is 0.342 /zH/f,nne Bank #2 Figure 5.41 below shows the one-line diagram of the capacitor banks te 230 kV substation MVA 11,500 ba Bank #1 Proposed at 80 Mvar Bank #2 Proposed at 80 Mvar Figure 5.41 A 230-kV substation with the proposed 2 x 80 Mvar three-pahse capacitor banks Note that Bank #2 is energized only when Bank #1 is already online. Determine the rated reactive power and capacitance of each three-phase capacitor Determine the rated per-phase voltage and current of the capacitor banks. The system normal operting voltage is 230 kV. Let us suppose that Bank #1 will automatically energized when the substation voltage is 0.98 pu. Determine the actual tive power injected by Bank #1 What is the steady state voltage at the substation after Bank # 1 is online? How about Determine the worst case energizing scenario for energizing Bank #1. What is the For the worst case switching scenario, determine the maximum inrush current peak Suppose Bank #1 is energized when the instantaneous system voltage is at zero volt both Banks #1 and #2 are online? maximum transient overvoltage and the corresponding switching frequency? when Bank #1 is energized. age. Co switching frequency mpute the maximum transient overvoltage, inrush current, and the corresponding H Bank #2 is energized only when Bank #1 is already in service. Show an equi rcuit during the fast transient of the back-to-back capacitor energizing worst case peak inrush current and its transient frequency when energizing Ban lent Determine the #2. Should va the results raise concerns? Please explain your rationale.

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