SOPD Voltage Control & System Reliability 2

Question 1

A system operator observes a sudden voltage collapse on a transmission corridor. What is the FIRST corrective action to take?

Accepted Answer

Insert reactive power support such as capacitor banks or SVCs

Answer

Voltage collapse is primarily a reactive power deficiency; inserting reactive support (capacitor banks, SVCs) is the first corrective action.

Question 2

What does the term 'voltage stability margin' represent in power system operations?

Accepted Answer

The distance in MW or MVAR loading from the current operating point to the voltage collapse point

Answer

Voltage stability margin is the MW or MVAR distance from the current operating point to the nose point (collapse point) on the P-V or Q-V curve.

Question 3

Under NERC Reliability Standards, which entity is primarily responsible for maintaining voltage within acceptable limits on the bulk electric system?

Accepted Answer

Transmission Operator (TOP)

Answer

The Transmission Operator (TOP) is responsible for maintaining transmission voltages within limits specified in their Operating Procedures.

Question 4

A generator is operating at rated MVA with a lagging power factor. To raise terminal voltage, the operator should:

Accepted Answer

Increase field excitation

Answer

Increasing field excitation raises the generator's internal EMF, which increases terminal voltage and causes the machine to supply more reactive power.

Question 5

Which phenomenon describes a situation where voltage actually rises as load increases, indicating a potential instability condition?

Accepted Answer

Voltage inversion

Answer

Voltage inversion occurs when a lightly loaded long line with shunt capacitance raises receiving-end voltage above sending-end voltage, indicating an unstable operating region.

(SOPD) System Operator/Power Dispatching Practice Test

(SOPD) System Operator/Power Dispatching Practice Test

SOPD Voltage Control & System Reliability 2