c) c)A batch of 2450 transformers from the production line have a mean output voltage of 215.3 V andthe Standard deviation of the output voltage is 2.8 V. If the voltages of the transformers in the boxare assumed to be normally distributed, determine the following:i)ii)iii)The number of Transformers with output voltages greater than 216.9 V.The number of Transformers with output voltages less than 213.1 V,The number of Transformers with output voltages between 214 V and 216 V.For this problem you should use the table of z-values shown in Figure 1.All the calculations must be clearly explained with suitable diagrams whereappropriate to aid understanding to a non-technical audience. Task 6The company kave checked the capacitances of a batch 120 of 100 µF capacitors and givenyou the results as shown in the group frequenty table 1 below.Use that data given to calculate the mean and standard deviation of the data.You shoutd provide clear explanation of the caleutations used and a suitably chosen graphical-representation of your results suitable for a non-technical audience.You may use a spreadsheet for these calculations, but you must provide clearevidence of the formulas used in each cell and submit the spreadsheet file with yourreport.Capacitance values between(µF)Class Frequency94-95.9796-97.91998-99.935100-101.931102-103.923104-105.95b)) The company automatically manufacture its control boards. The quality inspector hasdetermined that in each package, 89% of the control boards are within the correct tolerancevalues with respect to their functionality, the remainder were out of tolerance. If a randomsample of 6 boards are drawn from the package determine the probabilities that:i)ii)ii)3 of the sample boards are out of toleranceMore than 3 of the sample boards are out of toleranceLess than three of the sample boards are out of tolerance.

As asked only c) The number of transformers with an output voltage greater than 216.9 V is 695…

c) A batch of 2450 transformers from the production line have a mean output voltage of 215.3 V and the Standard deviation of the output voltage is 2.8 V. If the voltages of the transformers in the bo: are assumed to be normally distributed, determine the following: i) ii) ii) The number of Transformers with output voltages greater than 216.9 V. The number of Transformers with output voltages less than 213.1 V, The number of Transformers with output voltages between 214 V and 216 V. For this problem you should use the table of z-values shown in Figure 1. All the calculations must be clearly explained with suitable diagrams where appropriate to aid understanding to a non-technical audience.

c) A batch of 2450 transformers from the production line have a mean output voltage of 215.3 V and the Standard deviation of the output voltage is 2.8 V. If the voltages of the transformers in the bo: are assumed to be normally distributed, determine the following: i) ii) ii) The number of Transformers with output voltages greater than 216.9 V. The number of Transformers with output voltages less than 213.1 V, The number of Transformers with output voltages between 214 V and 216 V. For this problem you should use the table of z-values shown in Figure 1. All the calculations must be clearly explained with suitable diagrams where appropriate to aid understanding to a non-technical audience.

Power System Analysis and Design (MindTap Course List)

6th Edition

ISBN:9781305632134

Author:J. Duncan Glover, Thomas Overbye, Mulukutla S. Sarma

Publisher:J. Duncan Glover, Thomas Overbye, Mulukutla S. Sarma

Chapter3: Power Transformers

Section: Chapter Questions

Problem 3.55P: A single-phase l0-kVA,2300/230-volt,60-Hz two-winding distribution transformer is connected as an...

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The main advantage of A.C. systems over D.C. systems is: a) transformers can be used to change D.C. to A.C. IRtransformers can be used to change voltage levels. b) , 00 transformers can be used to change A.C. to D.C. d) ) transformers can be used to change power levels.
The statement given in which option related to transformers is wrong.A) Power transformers are used as step-down transformers in step-up consumption centers in production centers. B) Current transformers for measuring current at high voltageVoltage transformers are used to measure voltage. C) Voltage adjustment can be made with the on-load tap changing feature of power transformers. D) Transformers are of great importance in reducing power losses by increasing the power value in energy transmission. E) If there is no reactive power in energy transmission with direct current, the transformer cannot be used.
36. The essential condition for parallel opearation of two 1- transformers is that they should have the same (a) polarity (b) kVA rating (c) voltage ratio (d) percentage impedance. 37. If the impedance triangles of two transformers operating in parallel are not identical in shape and size, the two transformers will (a) share the load unequally (b) get heated unequally (c) have a circulatory secondary current even when unloaded (d) run with different power factors. 38. Two transformers A and B having equal outputs and voltage ratios but unequal percentage impedances of 4 and 2 are operating in parallel. Transformer A will be running over-load by. percent. (a) 50 (b) 66 (d) 25 (c) 33
10. In a transformer, the leakage flux of each wind- ing is proportional to the current in that winding because (a) Ohm's law applies to magnetic circuits (b) leakage paths do not saturate (c) the two windings are electrically isolated (d) mutual flux is confined to the core. 11. In a two-winding transformer, the e.m.f.per turn in secondary winding is always.........the induced e.m.f. power turn in primary. (a) equal to K times (b) equal to 1/K times (c) equal to (d) greater than. 12. In relation to a transformer, the ratio 20: 1 indi- cates that (a) there are 20 turns on primary one turn on secondary (b) secondary voltage is 1/20th of primary voltage (c) primary current is 20 times greater than the secondary current. (d) for every 20 turns on primary, there is one turn on secondary.
2.50 The nameplate on a 7.97-kV:266-V, 25-kVA single-phase transformer indicates that it has a series reactance of 7.5 percent (0.075 per unit). Calculate the series reactance in ohms as referred to (i) the low-voltage terminal and (ii) the high-voltage terminal. a. b. If three of these transformers are connected in a three-phase Y-Y connection, calculate (i) the three-phase voltage and power rating, (ii) the per unit impedance of the transformer bank, (iii) the series reactance in ohms as referred to the high voltage terminal and (iv) the series reactance in ohms as referred to the low-voltage terminal. c. Repeat part (b) if the three transformers are connected in Y on their HV
37. If the impedance triangles of two transformers operating in parallel are not identical in shape and size, the two transformers will (a) share the load unequally (b) get heated unequally (c) have a circulatory secondary current even when unloaded (d) run with different power factors. 38. Two transformers A and B having equal outputs and voltage ratios but unequal percentage impedances of 4 and 2 are operating in parallel. Transformer A will be running over-load by. ******* percent. (a) 50 (b) 66 (c) 33 (d) 25
Topic: VARIOUS TYPES OF TRANSFORMERS
Write in Briefly about circuit breaker, current transformer and voltage transformer
Consider a bank of this single-phase two-winding transformers whose high-voltage terminals are connected to a three-phase, 13.8-kV feeder. The low-voltage terminals are connected to a three-phase substation load rated 2.0 MVA and 2.5 kV. Determine the required voltage, current, and MVA ratings of both windings of each transformer, when the high-voltage/low- voltage windings are connected (a) Y-, (b) -Y, (c) Y-Y, and (d) -.
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.
A bank of three single-phase transformers, each rated 30MVA,38.1/3.81kV, are connected in Y- with a balanced load of three 1, Y-connected resistors. Choosing a base of 90MVA,66kV for the high-voltage side of the three-phase transformer. spify the base for the low-voltage side. Compute the per-unit resistance of the load on the base for the low-voltage side. Also, determine the load resistance in ohms referred to the high-voltage side and the per-unit value on the chosen base.
In developing per-unit equivalent circuits for three-phase transformers. under balanced three-phase operation. (i) A common Sbase is selected for both the H and X terminals. (ii) The ratio of the voltage bases Vbase/VbaseX is selected to be equal to the ratio of the rated line-to-line voltages VratedHLL/VratedXLL. (a) Only one of the above is true. (b) Neither is true. (C) Both statements are true.