Survey

* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project

Document related concepts

Current source wikipedia , lookup

Islanding wikipedia , lookup

Electrical ballast wikipedia , lookup

Mercury-arc valve wikipedia , lookup

Decibel wikipedia , lookup

Ground (electricity) wikipedia , lookup

Power inverter wikipedia , lookup

Variable-frequency drive wikipedia , lookup

Stray voltage wikipedia , lookup

Power electronics wikipedia , lookup

Opto-isolator wikipedia , lookup

Voltage regulator wikipedia , lookup

Surge protector wikipedia , lookup

Tesla coil wikipedia , lookup

Distribution management system wikipedia , lookup

Magnetic core wikipedia , lookup

Earthing system wikipedia , lookup

Buck converter wikipedia , lookup

Power engineering wikipedia , lookup

Rectifier wikipedia , lookup

Electrical substation wikipedia , lookup

Single-wire earth return wikipedia , lookup

Voltage optimisation wikipedia , lookup

Inductor wikipedia , lookup

Rectiverter wikipedia , lookup

Switched-mode power supply wikipedia , lookup

History of electric power transmission wikipedia , lookup

Mains electricity wikipedia , lookup

Resonant inductive coupling wikipedia , lookup

Alternating current wikipedia , lookup

Three-phase electric power wikipedia , lookup

Transformer wikipedia , lookup

Transcript
```EEE307
Electromechanical Energy Conversion
Homework I (Due on March 24th 2015)
1. An inductor of the form given below has dimensions:
Cross-sectional area Ac = 3.6 cm2 ; Mean core length lc = 15 cm ; N = 75 turns.
Assuming a core permeability µ= 2100µ0 and neglecting the effects of leakage flux and fringing
fields, calculate the air-gap length required to achieve an inductance of 6.0 mH.
2. Draw the magnetic circuit for the system given below:
3) The nameplate on a 9.2-kV:460-V, 46-kVA, single-phase transformer indicates that it has a
series reactance of 10 percent (0.10 per unit).
a) Calculate the series reactance in ohms as referred to (i) the low-voltage terminal and (ii) the
high-voltage terminal.
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) per unit impedance of the transformer bank, (iii) the
series reactance in ohms referred to the high-voltage terminal, and (iv) the series reactance in
ohms as referred to the low-voltage terminal.
EEE307
Electromechanical Energy Conversion
Homework I (Due on March 24th 2015)
c) Repeat part (b) if the three transformers are connected in ∆ on the high-voltage side and Y on
their low-voltage terminal.
4) A 15-kV: 150-kV, 150-MVA, 60-Hz single-phase transformer has primary and secondary
impedances of 0.0095 + j0.063 per unit each. The magnetizing impedance is j148 per unit. All
quantities are in per unit on the transformer base. Calculate the primary and secondary
resistances and reactances and the magnetizing inductance (referred to the low-voltage side) in
ohms and henrys.
5) A 50-kVA, 2400/240-V, 60-Hz single phase transformer has a short-circuit test performed on
its high-voltage side. The following test results are obtained:
Voltage (V)
Current (A)
Power(W)
Short-Circuit (LV shorted)
48
20.8
500
Open-Circuit (HV open)
240
5.4
150
a) Draw the transformers equivalent circuit.
b) Determine its voltage regulation, and efficiency at rated load, 0.8 power factor lagging, and rated
voltage at the secondary terminals.
```