ROEVER ENGINEERING COLLEGEPERAMBALUR-621212

DEPARTMENT OF ELECTRICAL AND ELECTRONICS ENGINEERING

QUESTION BANKSUBJECT CODE & NAME : EE 1401 – POWER SYSTEM OPERATION & CONTROL

YEAR / SEM : IV / VII

UNIT –IINTRODUCTION

PART-A1. What is the objective of power system control? (2)2. Define load and list out the types of loads. (2)3. List out the various needs for frequency regulation in power system. (2)4. What happens to frequency if the load on the generator increases? (2)5. What is spinning reserve? (2)6. Draw the load curve and load duration curve. (2)7. What is plant use factor? (2)8. Define Capacity Factor.9. What is the purpose Load Forecasting (2)

PART –B1. Explain the need for voltage and frequency regulation in power system. (16)2. Briefly discuss the classification of loads and list out the importantcharacteristics of various types of loads.(16)3. Define load curve and load duration curve. What do you understand by loadcurve? What informations are conveyed by a load curve?(16)4. Briefly explain the overview of system operation. (8)5. A generating station has the following daily loads:0-6 hr - 4500 KW6-8 hr - 3500KW8-12 hr - 7500KW12-14 hr - 2000KW14-18 hr - 8000KW18-20 hr - 2500KW20-24 hr - 5000KWSketch the load duration curve and determine the load factor and plant capacityfactor if the capacity of the plant is 12 MW (8)

UNIT –IIREAL POWER-FREQUENCY CONTROL

PART-A1. What is the function of load frequency control? (2)2. Define regulation. (2)3. State any two necessities to put alternators in parallel. (2)4. Give two conditions for proper synchronizing of alternators. (2)5. Define per unit droop. (2)6. What is meant by control area? (2)

7. What is area control error? (2)8. What is meant by AFRC? (2)9. Define inertia constant. (2)10. How is the real power in a power system controlled? (2)

PART –B1. Draw the block diagram representation of the speed control mechanism of anindividual generator. State the variables and parameters that are involved in thismodel. From this, develop the block diagram representation of a single controlarea. (16)2. Determine the primary ALFC loop parameters for a control area having thefollowing data:Total rated area capacity, Pr = 2000 MWNormal operating load, Pd = 1000 MWInertia constant H = 5.0Regulation R = 2.40 Hz/ pu MW.We shall assume that the load frequency dependency as linear meaning that theload would increase 1% for 1% frequency increase. (16)3. Draw a block diagram to represent a two-area system showing all necessarydetails and explain the various blocks. (16)4. Obtain a block diagram for the representation of single area dynamic analysisof uncontrolled case.(16)5. Briefly explain the LFC control of single area system. (16)6. A two area power system has two identical areas with parameters and operatingconditions:Rated capacity of the area = 1500MWNormal operating load = 750MWNominal frequency = 50HzInertia constant of the area = 5 sSpeed regulation = 3%Damping co-efficient = 1%Governor time constant = 0.06 sTurbine time constant = 0.25 sA load increase M1=30MW occurs in area1. Determine change in frequency andcompare the change in frequency obtained in single area and comment on thesupport. (16)7. What are the components of speed governor system of an alternator? Derive atransfer function and sketch a block diagram. (16)8. Draw the transfer function block diagram of a LFC for a single area power systemprovided with integral controller and explain the dynamic response for variousvalues of gain kI of the integral controller. (16)

UNIT-IIIREACTIVE POWER –VOLTAGE CONTROL

PART A1. List the various components in AVR loop. (2)2. What is the significance of stability compensation in AVR loop? (2)3. What are the methods of increasing response in AVR? (2)

4. Distinguish between on-load and off-load tap changing. (2)5. What are the methods of voltage control? (2)6. Compare series and shunt capacitors. (2)7. How is voltage control obtained by using tap changing transformer? (2)8. What is booster transformer? Where it is used? (2)9. What are the different types of static VAR compensators? (2)10. Draw the phasor diagram for static VAR compensators. (2)

PART –B1. Draw the circuit diagram for a typical excitation system and derive thetransfer function model and draw the block diagram (16)2. Explain stability compensation and effects of generator loading. (16)3. Discuss generation and absorption of reactive power. (8)4. Explain different types of static VAR compensators with a phasor diagram.(16)5. Discuss about the various methods of voltage control. (16)6. Explain the static and dynamic performance of AVR loop .(16)

UNIT –IVUNIT COMMITMENT & ECONOMIC DISPATCH CONTROL

PART-A1. What is the purpose of economic dispatch? What is meant by unitCommitment? (2)2. List the various constraints in modern power systems. (2)3. What are the advantages of using participation factor? (2)4. What is lagrangian multiplier? (2)5. Explain penalty factor. (2)6. Compare unit commitment and economic dispatch. (2)7. Draw incremental fuel cost curve. (2)8. When do discontinuities occur in the fuel cost curve and theIncremental cost curve? (2)9. What are all the points to be noted for a economic load dispatchincluding transmission losses? (2)

PART –B1. Draw the diagram and for obtaining the optimum dispatch strategy of N-bus systemneglecting the system transmission loss. (16)2. Draw the diagram and for obtaining the optimum dispatch strategy of N-bus systemtaking into account the system transmission loss. (16)3. Derive the expression for base point and participation method. (16)4. The input –output curve characteristics of three units are:F1=750+6.49 PG1+0.0035PG12

F2=870+5.75 PG2+0.0015PG22

F3=620+8.56 PG3+0.001PG32

The fuel cost of unit 1, 2, 3 is 1.0 Rs / Mbtu. Total load is 800 MW. Useparticipation factor method to calculate the dispatch for a load is increased to 880MW? (16)5. A two-bus system is shown in figure 1. If a load of 125 MW is transmitted fromplant 1 to the load, a loss of 15.625 MW is incurred. Determine the generation

schedule and the load demand if the cost of received power is Rs.24 / MWhr.Solve the problem using coordination equation and the penalty factor methodapproach. The incremental production costs of the plants are given below (16)dF1/dP1 = 0.025P1+ 15dF2/dP2 = 0.05P2 + 20

UNIT –VCOMPUTER CONTROL OF POWER SYSTEMS

PART-A1. Define Energy control centre. (2)2. What is contingency analysis program? (2)3. What is SCADA? (2)4. What are the functions of SCADA? (2)5. What are the different operating states of a power system ? (2)6. What is security monitoring and control? (2)7. List the factors that affect the power system security. (2)8. What are the important types of relays used for protection? (2)9. How is load forecasting classified depending upon the time period? (2)10. What is the use of digital computer in short circuit computations? (2)

PART –B1. Explain the different system operating states .(16)2. Discuss about automatic substation control using SCADA.(16)3. Explain about SCADA configuration.(16)4. Briefly discuss the various functions of energy control centre.(16)5. Explain the hardware components and functional aspects of SCADA system usinga fundamental block diagram.(16)6. Explain the various controls for secure operartion.(16)7. Explain briefly how the system states are continuously monitored andcontrolled(16)