Evaluate (130 points); Use 3 decimal places. 1. The annual load of a substation is given in the following table. During each month, the power is assumed constant at an average value. Find the (a) average load and (b) the annual load factor. Annual System Load January February March 8 Y 4 April May 26 2 6 2, Tv June 12 sing July 14 phas August 14 idea September 10 imp October 8 5Y5 November December 68 6 ma del

A 10 MVA three phase load is to be served by a three phase transformer at aline voltage of 13.8 kV. The supply side voltage(line-line) is 138 kV. Varioussingle phase transformers are available in the warehouse but all havewindings with voltage ratings under 100 kV and current ratings under 250 A.Is it possible to serve the load using only three single phase transformers? Ifso, specify the three phase connections and the low and high voltage ratingsof the single phase transformers.

1. A single-phase power system as shown in Figure 1 consists of a 240 V, 60 Hz generator supplying a load, Zod = 8 + j6 Q through a transmission line of impedance, Zne = 0.08 + j0.14 Q. Answer the following questions: (1) transformer, T; and T2. Determine the voltage at the load and transmission line losses without the (ii) Determine the voltage at the load and transmission line losses with the transformer, T, and T2. T1 T2 1:10 10:1 IG Zaine Zioad source Figure 1

A generator connected through 5 cycle CB to a transformer is rated 8000 kVA with the reactances of X"= 10 %, X₁ = 16% and Xa = 100 %. It is operating at no load and rated voltage when 3 phase short circuit occurs between breaker and transformer. Find: i) sustained short circuit in breaker ii) the initial symmetrical rms current in breaker iii) maximum possible d.c. component of short circuit in breaker iv) the momentary current rating of the breaker v) current to be interrupted by breaker vi) the interrupting kVA

Assume that there are two primary feeders supplied by a transformer T1. One of the feeders supplies an industrial load which occurs primarily between 8 AM, and 11 P.M. with a peak of 2400 kw at 5 P.M. The other one feeds residential loads which occur mainly betwveen 6 A.M. and 12 P.M., with a peak of 2000 kW at 9 P.M. The diversity factor of the load connected to transformer T1 is 1.3: The maximum diversified demand of the load connected to transformer T1.

Solution in typing please

In a PWM, how do we calculate duty cycle?

In the system shown in Figure 1, the transformers are connected star-star with both star points grounded and the generator is connected in star with its star points grounded. The per unit impedances of each element on a 40 MVA base are given in Table 1 and the voltage levels are given in Table 2. Z [p.u.] 0 2 tööt Generator 0.01 +j0.08 p.u. L Figure 1: A section of the distribution system Transformer T1 Line V BASE [KV] 0.04 + j 0.03 + j 0.15000000000000002 0.06000000000000000 Generator Table 1: Sequence impedances (p.u. on 40 MVA base) 3 T2 181. Line 3 10 Table 2: Voltage bases (kV) Load 1 Transformer T2 Load Current A load current of 11.316 kA is flowing with a lagging power factor of 90 %. Convert this to a current vector in per-unit. IL = 0.04 + j 0.06000000000000000

4.a. A demountable stud bushing on high-voltage leads eliminates the need fora. an oil stop.b. a gasket.c. a terminal lug. 4.a. A power transformer with standard insulation class of 69 kv will withstand an rms test voltage ofA. 140 kv.B. 440 kv.c. 69kv.

Consider the three single-phase two-winding transformers shown in Figure 3.37. The high-voltage windings are connected in Y. (a) For the low-voltage side, connect the windings in , place the polarity marks, and label the terminals a, b, and c in accordance with the American standard. (b) Relabel the terminals a, b, and c such that VAN is 90 out of phase with Va for positive sequence.