1

GATE EE 2015 Set 2

Numerical

+2

-0

The incremental costs (in rupees/$$MWh$$) of operating two generating units are functions of their respective powers $${P_1}$$ and $${P_2}$$ in $$MW,$$ and are given by
$$${{d{C_1}} \over {d{P_1}}} = 0.2{P_1} + 50$$$
$$${{d{C_2}} \over {d{P_2}}} = 0.24{P_2} + 40$$$

Where, $$$\eqalign{ & 20\,MW \le {P_1} \le 150\,MW \cr & 20\,MW \le {P_2} \le 150MW. \cr} $$$

For a certain load demand, $${P_1}$$ and $${P_2}$$ have been chosen such that $$\,\,d{C_1}/d{P_1} = 76\,Rs/MWh\,\,$$ and $$\,d{C_2}/d{P_2} = 68.8\,Rs/MWh.\,\,$$ If the generations are rescheduled to minimize the total cost, then $${P_2}$$ is ____________.

Where, $$$\eqalign{ & 20\,MW \le {P_1} \le 150\,MW \cr & 20\,MW \le {P_2} \le 150MW. \cr} $$$

For a certain load demand, $${P_1}$$ and $${P_2}$$ have been chosen such that $$\,\,d{C_1}/d{P_1} = 76\,Rs/MWh\,\,$$ and $$\,d{C_2}/d{P_2} = 68.8\,Rs/MWh.\,\,$$ If the generations are rescheduled to minimize the total cost, then $${P_2}$$ is ____________.

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2

GATE EE 2015 Set 1

Numerical

+2

-0

Consider the economic dispatch problem for a power plant having two generating units. The fuel costs in $$Rs/MWh$$ along with the generation limits for the two units are given below:

$$\eqalign{ & {C_1}\left( {{P_1}} \right) = 0.01\,P_1^2 + 30{P_1} + 10; \cr & \,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,100\,MW \le {P_1} \le 150\,MW \cr} $$

$$\eqalign{ & {C_2}\left( {{P_2}} \right) = 0.05\,P_2^2 + 10{P_2} + 10; \cr & \,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,100\,MW \le {P_2} \le 180\,MW \cr} $$

$$\eqalign{ & {C_1}\left( {{P_1}} \right) = 0.01\,P_1^2 + 30{P_1} + 10; \cr & \,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,100\,MW \le {P_1} \le 150\,MW \cr} $$

$$\eqalign{ & {C_2}\left( {{P_2}} \right) = 0.05\,P_2^2 + 10{P_2} + 10; \cr & \,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,100\,MW \le {P_2} \le 180\,MW \cr} $$

The incremental cost (in $$Rs/MWh$$) of the power plant when it supplies $$200$$ $$MW$$ is __________.

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3

GATE EE 2014 Set 1

MCQ (Single Correct Answer)

+2

-0.6

The fuel cost functions of two power plants are

Plant $${P_1}:\,{C_1} = 0.05\,Pg_1^2 + AP{g_1} + B$$

Plant $${P_2}:\,{C_2} = 0.10\,Pg_2^2 + 3AP{g_2} + 2B$$

Where, $$P{g_1}$$ and $$P{g_2}$$ are the generator powers of two plants and $$A$$ and $$B$$ are the constants. If the two plants optimally share $$1000$$ $$MW$$ load at incremental fuel cost of $$100$$ $$Rs/MWh,$$ the ratio of load shared by plants $${P_1}$$ and $${P_2}$$ is

Plant $${P_1}:\,{C_1} = 0.05\,Pg_1^2 + AP{g_1} + B$$

Plant $${P_2}:\,{C_2} = 0.10\,Pg_2^2 + 3AP{g_2} + 2B$$

Where, $$P{g_1}$$ and $$P{g_2}$$ are the generator powers of two plants and $$A$$ and $$B$$ are the constants. If the two plants optimally share $$1000$$ $$MW$$ load at incremental fuel cost of $$100$$ $$Rs/MWh,$$ the ratio of load shared by plants $${P_1}$$ and $${P_2}$$ is

4

GATE EE 2011

MCQ (Single Correct Answer)

+2

-0.6

A load center of 120 MW derives power from two power stations connected by 220 kV transmission lines of 25 km and 75 km as shown in the figure below. The three generators G1,G2 and G3 are of 100 MW capacity each and have identical fuel cost characteristics. The minimum loss generation schedule for supplying the 120 MW load is

Questions Asked from Power Generation Cost (Marks 2)

Number in Brackets after Paper Indicates No. of Questions

GATE EE Subjects

Electric Circuits

Electromagnetic Fields

Signals and Systems

Electrical Machines

Engineering Mathematics

General Aptitude

Power System Analysis

Electrical and Electronics Measurement

Analog Electronics

Control Systems

Power Electronics