1
GATE EE 2023
MCQ (Single Correct Answer)
+1
-0.33

The expressions of fuel cost of two thermal generating units as a function of the respective power generation $${P_{G1}}$$ and $${P_{G2}}$$ are given as

$$\matrix{ {{F_1}({P_{G1}}) = 0.1aP_{G1}^2 + 40{P_{G1}} + 120\,Rs/hour} & {0\,MW \le {P_{G1}} \le 350\,MW} \cr {{F_2}({P_{G2}}) = 0.2P_{G2}^2 + 30{P_{G2}} + 100\,Rs/hour} & {0\,MW \le {P_{G2}} \le 300\,MW} \cr } $$

where $$a$$ is a constant. For a given value of $$a$$, optimal dispatch requires the total load of 290 MW to be shared as $${P_{G1}} = 175\,MW$$ and $${P_{G2}} = 115\,MW$$. With the load remaining unchanged, the value of $$a$$ is increased by 10% and optimal dispatch is carried out. The changes in $${P_{G1}}$$ and the total cost of generation, $$F( = {F_1} + {F_2})$$ in Rs/hour will be as follows

A
$${P_{G1}}$$ will decrease and $$F$$ will increase
B
Both $${P_{G1}}$$ and $$F$$ will increase
C
$${P_{G1}}$$ will increase and $$F$$ will decrease
D
Both $${P_{G1}}$$ and $$F$$ will decrease
2
GATE EE 2023
MCQ (More than One Correct Answer)
+1
-0

The bus admittance ($$Y_{bus}$$) matrix of a 3-bus power system is given below.

$$\quad\quad$$$$\matrix{ 1 & \quad\quad\quad2\quad\quad & 3 \cr } $$

$$\matrix{ 1 \cr 2 \cr 3 \cr } \left[ {\matrix{ { - j15} & {j10} & {j5} \cr {j10} & { - j13.5} & {j4} \cr {j5} & {j4} & { - j8} \cr } } \right]$$

Considering that there is no shunt inductor connected to any of the buses, which of the following can NOT be true?

A
Line charging capacitor of finite value is present in all three lines
B
Line charging capacitor of finite value is present in line 2-3 only
C
Line charging capacitor of finite value is present in line 2-3 only and shunt capacitor of finite value is present in bus 1 only
D
Line charging capacitor of finite value is present in line 2-3 only and shunt capacitor of finite value is present in bus 3 only
3
GATE EE 2005
MCQ (Single Correct Answer)
+1
-0.3
The p.u. parameters for a $$500$$ MVA machine on its own base are:
Inertia, M = $$20$$ p.u.; reactance X = $$2$$ p.u. The p.u. values of inertia and reactance on $$100$$ MVA common base, respectively are
A
$$4, 0.4$$
B
$$100, 10$$
C
$$4, 10$$
D
$$100,0.4$$
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