Consider a 60-Hz radial three-phase distribution feeder having the following characteristics: Substation three-phase transformer: wye-wye...

 

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Consider a 60-Hz radial three-phase distribution feeder having the following characteristics: • Substation three-phase transformer: wye-wye grounded 132 kV-13.2 kV, 10 MVA, Zeq = (0.5 + j9) % (on the transformer base impedance) Infinite bus is number 1 and transformer high voltage side is bus 2 Choose the transformer base values as the system base values Three-phase short-circuit current at the primary side of substation transformer (bus 2): 3 KA • Feeder segment positive impedances: To 4 5 6 From 3 4 5 6 7 8 9 10 7 8 9 10 11 R in Ohms 0.09 0.30 0.20 0.30 0.40 0.60 0.90 0.55 X in Ohms 0.20 0.60 0.40 0.75 0.45 0.60 0.80 0.65 Remember that BALANCED three-phase systems are solved on a per-phase basis with all components being wye connected. • The goal of this homework assignment is to model the distribution system as "seen" from node or bus 7 since it is the site of an industrial complex having non-linear loads. You are required to perform the following: (5) Consider that the non-linear load at node/bus 7 is drawing the following current into the distribution system (angles are given with respect to bus 7 voltage): i(t) = √2 125 sin(2π60t-40°) + √2 25 sin(5(2760t-150°))+ √2 18 sin(7(260t-210°)) A Calculate the voltage at node/bus 7 using the principle superposition (which is applied in the time domain) and phasor theory to solve circuits at the individual frequencies. 6) Plot the results of (5) over 4 cycles of the fundamental frequency. Consider a 60-Hz radial three-phase distribution feeder having the following characteristics: • Substation three-phase transformer: wye-wye grounded 132 kV-13.2 kV, 10 MVA, Zeq = (0.5 + j9) % (on the transformer base impedance) Infinite bus is number 1 and transformer high voltage side is bus 2 Choose the transformer base values as the system base values Three-phase short-circuit current at the primary side of substation transformer (bus 2): 3 KA • Feeder segment positive impedances: To 4 5 6 From 3 4 5 6 7 8 9 10 7 8 9 10 11 R in Ohms 0.09 0.30 0.20 0.30 0.40 0.60 0.90 0.55 X in Ohms 0.20 0.60 0.40 0.75 0.45 0.60 0.80 0.65 Remember that BALANCED three-phase systems are solved on a per-phase basis with all components being wye connected. • The goal of this homework assignment is to model the distribution system as "seen" from node or bus 7 since it is the site of an industrial complex having non-linear loads. You are required to perform the following: (5) Consider that the non-linear load at node/bus 7 is drawing the following current into the distribution system (angles are given with respect to bus 7 voltage): i(t) = √2 125 sin(2π60t-40°) + √2 25 sin(5(2760t-150°))+ √2 18 sin(7(260t-210°)) A Calculate the voltage at node/bus 7 using the principle superposition (which is applied in the time domain) and phasor theory to solve circuits at the individual frequencies. 6) Plot the results of (5) over 4 cycles of the fundamental frequency.

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To model the distribution system as seen from nodebus 7 we need to first calculate the perphase positive sequence impedance of the feeder segments between buses 7 and 2 To do so we convert the impedan... View the full answer