SOPD Voltage Control & System Reliability

Question 1

Which device injects or absorbs reactive power dynamically to support transmission‑level voltage?

Accepted Answer

Static VAR Compensator (SVC)

Answer

On‑load tap changer

Answer

Frequency converter

Answer

Phase‑shift transformer

Question 2

Voltage stability margin refers to:

Accepted Answer

Distance to voltage collapse

Answer

Frequency deviation

Answer

Reserve capacity

Answer

System inertia

Question 3

An on‑load tap‑changing transformer regulates voltage by:

Accepted Answer

Adjusting tap position to alter turns ratio

Answer

Varying phase angle

Answer

Switching series capacitors

Answer

Changing line impedance

Question 4

Power factor correction improves reliability primarily by:

Accepted Answer

Reducing line current and voltage drop

Answer

Increasing real power losses

Answer

Raising system frequency

Answer

Providing inertial response

Question 5

Which fast‑acting device offers multilevel voltage support similar to an SVC but with IGBT technology?

Accepted Answer

STATCOM

Answer

Synchronous condenser

Answer

Shunt reactor

Answer

Series capacitor

Question 6

Loss of Load Probability (LOLP) is an index measuring:

Accepted Answer

Chance of generation shortfall

Answer

Voltage drop magnitude

Answer

System oscillations

Answer

Transformer overheating

Question 7

Reactive power reserves are scheduled so that after an N‑1 contingency the voltage remains within:

Accepted Answer

±5 %

Answer

±1 %

Answer

±3 %

Answer

±10 %

Question 8

A Ferranti effect is most pronounced on:

Accepted Answer

Lightly loaded long transmission lines

Answer

Heavily loaded short feeders

Answer

Distribution transformers

Answer

Generator stators

Question 9

Primary frequency response can indirectly aid voltage control because:

Accepted Answer

Stable frequency reduces real‑reactive coupling stress on AVR systems

Answer

It injects capacitive VARs directly

Answer

It switches capacitor banks automatically

Answer

It adjusts tap changers