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Voltage/VAR/Frequency Control Quiz

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Questions and Answers

What is the formula for instantaneous power?

$p(t) = \frac{1}{2} V_m I_m \cos(\theta_v - \theta_i) + \frac{1}{2} V_m I_m \cos(2\omega t + \theta_v + \theta_i)$ (correct)

$p(t) = P + Q(t)$

$S = V I cos\theta + jV I sin\theta$

$p(t) = [\cos(\theta_{vi}) - \cos(2\omega t - \theta_{vi})]^2$

What does the complex power S represent?

Reactive power, Q, that supports the system electromagnetically

Single system frequency, f

Voltage profile, V

Real power, P, able to perform useful work (correct)

In normal system operation, which dynamics are decoupled from voltage/reactive-power?

Real power and reactive power dynamics

Real power and frequency dynamics (correct)

Instantaneous power and frequency dynamics

Voltage and frequency dynamics

What is the formula for real power?

$P = V I cos\theta$ Signup and view all the answers

What is the average of the expression for instantaneous power?

$P = \frac{1}{2} V_m I_m \cos(\theta_v - \theta_i)$ Signup and view all the answers

What does the formula $p(t) = V_{max}I_{max} [cos(\theta_{vi}) - cos(2\omega t - \theta_{vi})]$ represent?

Instantaneous power Signup and view all the answers

What is the formula for average power from the given expression for instantaneous power?

$P = \frac{V_{m}I_{m}cos(\theta_{v} - \theta_{i})}{2}$ Signup and view all the answers

What is the complex power denoted by the symbol S in the context of power systems?

$S = P + jQ$ Signup and view all the answers

What is the angle represented by $\theta$ in the equation $S = V I cos\theta + jV I sin\theta$?

Power factor angle Signup and view all the answers

What do real power, P, and reactive power, Q, represent in a power system?

P is able to perform useful work, Q supports the system electromagnetically Signup and view all the answers

Which formula represents the instantaneous power in the time domain?

$p(t) = V_m I_m cos(\theta_v - \theta_i) + V_m I_m cos(2\omega t + \theta_v + \theta_i)$ Signup and view all the answers

What does the complex power S represent in the context of power systems?

Real power and reactive power Signup and view all the answers

Which angle is represented by $\theta$ in the equation $S = V I cos\theta + jV I sin\theta$?