Quizzes 1-3
If we use the applied voltage as the reference. The voltage source is at ________ degrees. A. -90 degrees B. Zero C. 180 degrees D. 90 degrees
B. Zero
Match the following Electrical system conditions with the associated time scales given. A. (kHz)(msec) B. (50 or 60 Hz)( Seconds) C. (MHz)(µsec) 1. Steady State Conditions 2. Dynamic Analysis 3. Transient Analysis
1:B (Steady State-seconds) 2:A (Dynamic Analysis - msec) 3:C (Transient Analysis - µsec)
Match the variable definitions with the type of three phase system. A. Balanced three phase Delta connected system. B. Balanced three phase Wye connected system. 1. The line current is equal to the phase current. 2. The amplitude of the line current is equal to square root of (3) times the phase current.
1:B (line current = phase current - wye) 2:A (line current amp = root(3)*phase current amp - delta)
Match the variable definitions with the type of three phase system. A. Balanced three phase wye connected system. B. Balanced three phase delta connected system. 1. Line current Lags phase current by 30 degrees. 2. The line current is the same phase as the phase current.
1:B (line current lags phase current - delta) 2:A (line current = phase current - wye)
Match the variable definitions with the type of three phase system. A. Delta Connected. B. In a 3 phase balanced wye connected system. 1. The amplitude of the line to line voltage is equal to the Square root of (3) times the amplitude of the line to neutral voltage. 2. The amplitude of the line to line voltage is equal to the the amplitude of the line to neutral voltage.
1:B (line volt amp=root(3)*neutral volt amp - wye) 2:A (line volt amp = neutral volt amp - delta)
Match the variable definitions with the type of three phase system. A. Balanced 3 Phase Wye connect circuit. B. Balanced 3 phase delta connected circuit. 1. The phase of the line to line voltage is equal to the the phase of the line to neutral voltage. 2. The phase of the line to line voltage leads the amplitude of the line to neutral voltage by 30 degrees.
1:B (line volt phase = neutral volt phase - delta) 2:A (line volt phase leads neutral volt phase - wye)
Match the power terms with the unit. A. Watts B. VAR C. VA 1. Apparent Power 2. Real Power 3. Reactive Power
1:C (Apparent Power-VA) 2:A (Real Power-Watts) 3:B (Reactive Power-VAR)
The phasor in complex number rectangular form is better for __________. A. Addition and subtraction B. Multiplication and division C. Multiplication and subtraction D. Addition and division
A. Addition and subtraction
What is the required number of wires needed to every n phase system? A. n+1 B. 0 C. n-1 D. n
A. n+1
Select all that apply: The electric utility was a vertically integrated monopoly. What was the utility environment at that time? A. Utilities never interconnected their systems until deregulation. B. Economies of scale keep resulted in decreasing rates C. Within its service territory each utility was the only game in town D. Neighboring utilities functioned more as colleagues than competitors
B. Economies of scale keep resulted in decreasing rates C. Within its service territory each utility was the only game in town D. Neighboring utilities functioned more as colleagues than competitors
High power factor means that the current angle is very small with respect to the reference voltage, cosine of that angle is closer to 1. Select the answer which does not result naturally from this fact. A. The real portion of the current vector is much larger than the reactive portion of the current vector. B. More of the apparent power is going towards feeding the inductive element of the load than supplying real power. C. Reduced line current, reduced copper losses in the transmission and distribution line. D. Less voltage drop across the line, generator doesn't have to generate higher voltage to compensate for the voltage drop or more real power.
B. More of the apparent power is going towards feeding the inductive element of the load than supplying real power.
For a three phase system, being balance means that the amplitude of the voltages are the same and the angles between the phases are? A. 45 degrees electrical B. 180 degrees electrical C. 120 degrees electrical. D. 90 degrees electrical
C. 120 degrees electrical.
The capacitor current always ________ the capacitor voltage A. Directly opposite in phase. B. The same phase C. Leads D. Lags
C. Leads
Angular rotation is always defined as positive in the _________ direction. A. Clockwise B. In +Z direction C. In the -Z direction. D. Counter clockwise
D. Counter clockwise
The inductor voltage always _______ the inductor current. A. Equal to B. Lags C. directly opposite in phase. D. Leads
D. Leads
The phasor in complex number polar form is better for __________. A. Subtraction and division. B. Addition and subtraction. C. Multiplication and addition. D. Multiplication and division.
D. Multiplication and division.
To convert the balanced wye connected 3 phase load to the equivalent balanced delta connected 3 phase load, you need to: A. Multiply the balanced wye connected 3 phase load by square root of 3. B. Divide the balanced wye connected 3 phase load by square toot of 3. C. Divide the balanced wye connected 3 phase load by 3. D. Multiply the balanced wye connected 3 phase load by 3.
D. Multiply the balanced wye connected 3 phase load by 3.
In a balanced three phase circuit. The sum of the three currents must sum to_______. A. Infinity. B. A scalar sum of all three curent magnitudes. C. An non-zero vector sum of the three currents. D. Zero
D. Zero
True or False A low power factor load means that the load is mostly capacitive.
False
True or False A major argument for deregulating the electric power industry is to drive the electricity rates downward, to reduce the rates the consumer would pay to buy electrical energy. This became true after deregulation.
False
True or False Each power utility company sets the price at which they sell their power to the consumers in the United States.
False
True or False In a Smart Grid, the power will continue to flow only from the electric power utility to the consumer without changes.
False
True or False In a balanced system, the neutral current can be non-zero.
False
True or False It has always been convenient to integrate renewable energy sources in the traditional power grid than in the Smart Grid.
False
True or False Power systems need to build enough generation and transmission capability to meet the peak load demands.
False
True or False RMS and peak mean the same thing.
False
True or False The Smart Grid promises the same kind of consumer involvement as the traditional grid.
False
True or False The aging infrastructure of the existing traditional power system was NOT a part of the consideration for establishing the Smart Grid.
False
True or False The amplitude used in phasor notion is the RMS amplitude.
False
True or False The initial assumption for generation is that the source is a voltage source, which means that only the voltage is constant.
False
True or False The load must always absorb real and reactive power.
False
True or False Voltage lags Inductor current
False
True or False Voltage leads Capacitor current
False
True or False You can solve unbalanced 3 phase connected power system by treating it as if the system is balanced.
False
True or False An actual transmission line is anything lossless, it is to be modeled with resistances, inductances, and capacitances.
True
True or False Big data will play a role in Smart Grid.
True
True or False Enabling electric vehicles integration is a part of the mission of the Smart Grid.
True
True or False Energy is defined as Integration of power over time.
True
True or False In order to compensate for low power factor load, utilities will often install capacitors in parallel with the load.
True
True or False PURPA of 1978 deregulated the electric power industry because:1970's brought inflation, increased fossil-fuel prices, increased electric rates, calls for conservation ,and growing environmental concerns.
True
True or False Power is defined as the Instantaneous consumption of energy.
True
True or False The Smart Grid is designed to be self healing, which means that it is designed to automatically detect problems, prevent and minimize system outages.
True
True or False The Smart Grid needs to be resilient against cyber attacks and other man made disruptions.
True
True or False The load in an ideal power system is modeled as a resistance.
True
True or False The power factor angle theta is the angular difference between the reference voltage angle and the current angle.
True
True or False The total complex power for loads in series AND parallel, is simply the sum of the individual load powers.
True
