Lecture 7 - System design and power flow

Question 1

In power flow analysis, which 4 quantities are associated with each bus?

Answer 1

• The real power
• The reactive power
• The voltage magnitude
• The phase angle between voltages

Question 2

There are 3 types of buses that are represented in the load flow calculations. Which?

Answer 2

• Slack bus, provides the additional real and reactive power to meet the losses
• Voltage controlled buses
• Load buses

Question 3

What is specified in a slack bus for load flow calculations?

Answer 3

Voltage magnitude

Angle

Question 4

What is specified in a voltage controlled bus for load flow calculations?

Answer 4

Voltage magnitude

Real power

Question 5

What is specified in a load bus for load flow calculations?

Answer 5

Real and reactive power

Question 6

What is the goal of an OPF?

Answer 6

Determine the “best” way to instantaneously operate a power system. Best usually means to minimize operating cost.

Question 7

Which are the available controls (optimization variables) for OPF?

Answer 7

• Generator MW outputs
• OLTC transformer taps, phase-shift taps
• Reactive power compensation devices (switched capacitor settings, SVCs)
• Load shedding

Question 8

What are building lines for and what are they limited by?

Answer 8

To transfer power from one point to another

• Power
• Voltage
• Distance

Question 9

What is on-line analysis?

Answer 9

State estimation
Security analysis
Economic analysis
        -Optimal operation
        -Loss coefficients
        -Optimal pricing

Question 10

What is off-line analysis?

Answer 10

Operation analysis
Planning analysis
           -Network expansion planning
           -Power exchange planning
           -Security and adequacy analysis
                    -Faults
                    -Stability