Seat No,: Enrolment No, GUJARAT TECHNOLOGICAL UNIVERSITY Subject Coaer2 170 ESTER (NEW) EXAM! INATION ~ Wi ‘TER 2022 fublect Name:Interconnected Power System nee-atns cette AM TO 01 200 PM Total Marks:70, 1. Attempt all questions, zy Ke suitable assumptions wherever necessary, 3. Figures to the right indicate tui marks, 4. Simple and non-programmat QI (a) Deseribe the ad Q2 (a) What are the advantages of You, —Y Cla“ 03 (©) Explain the following — ch. 2. 04 1. Tie set and Cut set matrix. 2. Primitive network. (©) Obtained Zsuusing Zpubuilding algorithm forthe system whose data is given 07 below. = Ch-2 Line No. Bus Code Impedance (Q) 1 R-1 06 2 R-2 05 3 1-3 0.25 4 2-3 05; Assume bus R as the reference bus OR © ‘The following is the system data for a load flow solution 07 Bus code Admittance — ch- % 1-2 2-58 1=3 1=i4 2-3 0.66 = 2.66 2-4 1-j4 3-4 | 2-j8 Bus es tf S a % Voltage 1 h 2 oO 0 1.06 2 0 0 0.5 02 2 3 0 0 04 03, 7 L_4 Oo 0 0.3 0.1 2 Find the bus voltage V2 and V3 at the end of first iteration using GS method. Q3 (a) Drive static load flow equation. — ch-3 03 (b) Give the bus eapseion for load flow study. What is importance of each 04 one? — Ch~ ge ‘lain all types of modifications when 07 (¢) Discuss Zs building algorithm. Expl x ° transmission lines are added between buses. - ch~B. Scanned with CamScannerQ3 @ Q4 Q4 Qs Qs (b) ©) (a) (by © @) () © @) ) © (a) (b) © OR Why one of the buses is taken as slack bus in load flow study? Ch— o ‘Compare the Decoupled load flow method and Fast decoupled load flow methods for load flow solution — Ch-3 With the help flow chart explains Newton Raphson method of load flow study. Ly cha Draw Heat rate curve ad Incremental rate curve with appropriate notation, Explain the following methods of voltage control Ly chy 1, On load and off load tap changing transformer. 2. Shunt and series compensation, A simple power system consists of two plants connected by a transmission line. The load in the system is directly connected at the bus of plant 2. When 100 MW power floes from plant I to plant 2 then 15 MW is lost in transmission line. The incremental costs of the two plans are — ¢ 4-4 aC, * = 0.20P, +22 Rs/MW — hr SF = 0.15P; + 30 Rs/MW — hr Calculate the economic loading of plants 1 and 2 for system = 60. Also calculate the transmission loss and total load demand. —> OR Drive an expression for the coordination equation for optimal operation of power system. —? For an isolated power system, develop block diagram representation of the ‘Speed Governing /system for frequency control — Ch -5 Derive the expression for B-loss co-efficient for a two plant power system. Explain why their unitisMW-1 — Ch-4 Explain: steady state stability and Transipt sibility for synchronous generator connected with infinite bus. —> Cla- Discuss any two applications of equal area criteria. — Ch- 6 Find the steady state power limit of system consisting of a generator equivalent reactance 0.50 pu connected to an infinite bus through a series reactance of 1.0 pu. The terminal voltage of the generator is held at 1.20 pu and the voltage of the infinite bus is 1.0 pub oa ind Drive the relation between angular momentum (M) and inertia constant (H) A100 MVA, 2 Pole, 50 Hz generator has a moment of inertia 50 x 10° kg.m?. Calculate energy stored in the rotor at the rated speed. Also calculate the 03 04 07 03 04 07 > Ch-6 03 04 inertia constant H and Angular momentum of the rotor at rated speed. —Ch~ Using equal area criterion, derive an expression for critical clearing angle for a system having a generation feeding a large system through double circuit 07 line. Lych-6: Scanned with CamScanner %,2 Seat No.: Subject Code:2170901 Subject Name:Inter Connected Power System ‘Time:10:30 AM TO 01:00 PM Enrolment No,__ GUJARAT ‘TECHNOLOGICAL UNIVERSITY BE ER-VII (NEW) EXAMINATION - SUMMER 2021 Date:05/08/2021 Total Marks: 70 Instructions: 1, Attempt all questions. 2. Make suitable assumptions wherever necessary. 3. Figures to the right indicate full marks. Qu Q2 Q3 @) (b) © @ @) © © @) (b) © (@) (b) © List out the functions of load dispatch centre. — Ch“ 03 In the equation Yous ATYA, what are the matrices Y and A indicates and 04 also mention their dimensions, — ¢- 2 ‘What is Interconnected Power System? State Advantages and 07 Disadvantages of interconnected power system. — Ch—b 7 the Power System Shown in Fig. (1), Determine bus incidence matrix 03 es Gt 3 1 2 @ ‘What do you understand by Unit Commitment? 04 t—“—ists——S— modifications. “he OR ‘What is incremental fuel cost? Give the steps for finding optimal Londing 7 rgenerators for system having N no, of generator in a plant a2 Give classifications of buses in power system for load flow analysis? ch» ‘Compare NR and GS method for oad flow analysis. —> Ch — 2 04 The incremental fuel costs of a two unit plant are given, by 07 qeiidPs=0.10P1120, & ACoA eO12Pr#15— OF 4 sees Pl and PZ rein MW. The plant pple # lod of 3000 Find weer e toad scheduling of two units and the incremental fuel cost Neglect losses. — cH! 4 oR eS Draw Block diagram of Automatic Generation Control (AGC). ~ CA~ 03 ol for controlling frequency in powersystem. 04 Explain Flat frequency cont Lo} ch} determine the voltages V2, V3 and V4 at the 07 ‘Gauss-Seidel method for the following dats ‘Assuming flat voltage start, tance of 2-j4 pu. Neglect all the shunt ‘end of first iteration using Each of the line has a series admit ch. admittances, ——) Scanned with CamScanner -Chd[Bus fay 2 [os 3 [1 © 4+ [03 4 (a) Describe the significance of load flow analysis. — Ch- > _ 03 et 3 Whaat is critica load angle and minimum load angle? Show with the power 04 angle curve, __» Ch-6 | load 07 (©) Explain clearly with a flow chart, the Computational procedure for loa flow solution using Gauss-Seidel method. —Y Ch3 OR 4 (@) How shunt compensation differs with series compensation in voltage 03 control? > Ch- (©) A 100MVA synchronous generator operates on full load ata frequency of 04 S0Hz. A 40 MW load is suddenly removed from the system. Due to time lag in the govemor system, the steam valve begins to close after 0.5 Seconds. Determine the change in frequency that occurs in this time. Assume H=SMJIMVA —>, Ch-5. (© With the help of neat diagram, Explain turbine speed governing system. 07 Also derive its mathematical model. Q5 (a) Define Steady state stability and Transient stability. —7 Ch-C 03 (®) Derive the power angle equation Pe=Pmax Sind. -— Ce 04 (© Explain various techniques to improve transient stability ofpowersystem. 07 ; R ch-& Q5 (a) Write a short note on Blackout, — Oh-L 03 (b) Explain the concept of equal area criterion, — Cl - € 04 (©) Describe the methods for voltage Control adopted for large size power 07 system indetail, =, CAs Scanned with CamScannerSeat No.: Enrolment No. GUJARAT TECHNOLOGICAL UNIVERSITY BE - SEMESTER- VII (NEW) EXAMINATION - WINTER 2021 Subject Code:2170901 Date:29/11/2021 Subject Name:Interconnected Power System 0 PM TO 05:00 PM Total Marks: 70 1. Attempt all questions. 2. Make suitable assumptions wherever necessary. 3. Figures tothe right indicate full marks. 4. Simple and non-programmable scientific ealeulators are lowed. MARKS Q.1 (a) Explain the concept of interconnection. State its advantages in brief —> Ch-“L 03 (b) What is load flow study? What kind of information is obtained from load flow 04 study? —y ch- 3 (©) What is cascade tripping and network islanding? Also explain the functions 07 carried out by various load dispatch centres —> ch 1. Q2 (a) Explain the meaning of graph, tree and link. What do you understand by 03 primitive network? —? Ch-2 (b) Explain how buses are classified in power systems? - Ch-3 04 (@) Thelin resistances and reactance fora 4-bus sytem are given in able flows If 07 the line between bus-1 and bus-2 is not connected find Yaus matrix, — CA Line (bus to bus) _| Resistance R (pu) | Reactance X (pu) 12 0.05 0.15 13 0.10 0.30 23 0.15 0.45 24 0.10 0:30 34 0.05 0.15 I the line between bus-I and bus-2 is connected find the new Yous matrix. OR (©) In FDLF method, which elements of Jacobian are set to zero? Give reasons. 07 for the same. In a typical power system, if the self susceptance Bi >> Qi, provethat ny Ean 28; -ViBit «? Q3. (a) State the assumptions made in approximate load flow method -C* ~ 0B (b) Give reasons for the following (i) Bus admittance matrix is a sparse matrix” 04 Gi) An acceleration factor is commonly used in load flow for GS method (©) Compare NR and GS method of load flow — CH3 07 OR P Q3. (a) Explain why frequency control is important? What are the targeted limits 03 thin which frequency is to be maintained? Which power system component is most adversely affected due to frequency deviation? (b) Ona system consisting of two generating plants, the incremental costs in RMWhr 04 with P; and P2 in MW are dCy/dP; = 0.16P; + 32 dCy/dP: = 0.24P; + 36 ‘The system is operating on economic dispatch with P, = P= 100 MW and &PL/SP2 2 Find the penalty factor of plant 1. ©" 4 Scanned with CamScannerQa Q4 as Qs ©) (a) (b) © (a) (b) © (a) (b) © (a) (b) © lant power 5) Derive the expression for B-loss co-effi re ey Pp erive the en ; cients fora Explain why their unit is MW! = ees a thin limits? g frequency within limits {What is fat requeney contol method for regulating frequency ion iy Derive the criteria for most economic dispatch when glected 5 ch-G . fly ball Isp ge in cred by hdl sero linkage mechanism —> ch- and oR Define steady state and transient aabilty > o . Explain equal area criteria of stability.» ch= a Toso Mw generators operate in parallel. The settings of the povernars a such that the rise in speed from full load to no-load is 2% in one Li hi TW 3% in another. If each machine is fully loaded when the total load is 100 MW, ‘what would be the load on each machine when ate 60 MW? Give the relation between inertia constant H and Reuter momentum M, State their Significance. 5 Cly-S What is synchronizing coefficient? How does it help in determining system stability —» Ch-¢ Discuss numerical solution of swing equation u Log OR Explain the terms critical Clearing angle and critical clearing time in connection with transient stability of a power system, —ch-¢ A synchronous generator delivers power to an infinite bu 18 point by point method input to the generator is increased to 0, mine (i) the kinetic seney Stored in moving parts of the generator (ii) the acceleration of the generator. If the acceleration is maintained for 7.5 cycles, calculate (iii) the change in rotor angle, and (iv) the speed in Tpm at the end of acceleration eter 07 cy 04 07 03 04 07 03 04 07 03 04 07 Ly as, Scanned with CamScannerSeat No.: Enrolment No. GUJARAT TECHNOLOGICAL UNIVERSITY “TER-VII (NEW) EXAMINATION ~ WINTER 2020 BE- SEM Subject Code:2170901 Date:25/01/2021 Subject Name:Inter Connected Power System Total Marks: 56 ‘Time:10:30 AM TO 12:30 PM Instructions: Qu Q2 Q3 Q4 I. Attempt any FOUR questions out of EIGHT questions, 2, Make suitable assumptions wherever necessary. 3, Figures to the right indicate full marks. (a) State the purpose of load flow study. What information is available from load flow study? —) Ch- 6. (b) Inapower system consisting of two generating tations the incremental costs in RMWh are ICI = 0.15P: + 35, 1C2 = 0.20P2 + ‘28. The plant supplies a load of 150 MW. Neglecting losses determine the most economical division of load. — Ch ~ (6 From the first principles, derive the swing equation for synchronous machine > ches (2) What is meant by interconnected power system?” State its advantages Loth-t (b) Discuss lat frequency method for frequency control ine i 5 h- 5, (6) Fora 3-bus system, the line impedances in pv are 8/60 below Line (bus to bus) impedance — | Gye. 12 0.06 + j0.18 13 0.03 + j0.09 23 0.08 + j0.24 Determine Yaus matrix load flow? Comment. (a). Is FDLF method superior to NR met of L 5 ch? | (b) A power system has two generating stations and power is being dispatched a eevymcally with Py = 150 MW and Pa= 275 MW. The loss coefficients are Fae poor MW", Biz = -0.0001 MW" , Bra = 0.0013 MW" Find the penalty factor of plant 1. —> O74 (c) Derive the transmission Joss formula explaining current distribution factors Clearly state all assumptions made in above derivation. induced emfof 1.6 puis connected to an infinite bus having voltage of 1.0 pu. Ifthe bus bus ar has reactanes of 0.6 pu and the Alternator has reactance of 0.2 pu find the steady state stability limit in pu (b)_ Write short notes on Tie line load bing control (a) Analtemator having an (o) _Deseribe the turbine speed aveming system for controlling the real poser flow in power system ——> Ch—S Scanned with CamScanner 03 04 07 03 07 03 04 07 6B 6 > Ow of 07Q5 (a) Define steady state stability andl transient stability — Ch © (©) A synchronous generator of reetance 0.4 pu is connected to ce 0 pu) though transformers and transmission line ha: 04 2 pu. The genertor no load voltage is 1.2 see. Calculate the frequency of natural os perme ror i Houle! (9 000% oF ts maximum power transfer limit, Assume f \ = 60 Hz ay Ch og (6) Explain how existing Zivs mitriy is modified when a link is added between 97 {vo old buses (Type 4 modification, —> cl 3, leria of stability — Ch- 6 03 Q6 (a) Discuss equal area (b) What is synehron ing coetticient? How it helps in determining system 04 Stability? = — Cty (©) State and explain different methods of veltage control 07 Loach 5 7 (a) Explain the phenomena of cascade tripping in power s stems 03 Q7 ¢ a Dl " ipping in pi veysys (©) Discuss the tasks carried out by Lond Dispatch 1 Centre. 04 (©) Explain the method of numerical solution of swing equation 07 Ly aH-c¢ Q8 (@) Explain the reclosure case of equal area criterion showin, the critical clearing 03 angle 8 and angle of reclosure Sy. > SCh—- 6 (0) Two generators operate in parallel and supply a total load of 400 MW. The 04. capacities of the machines are 200 MW and 500 MW and both the generators have droop characteristics of 4% from no load to full load. Calculate the load taken by the each machine assuming fiee governor action. Also find the system frequency at this load, No load frequency is 50 Hz. — Ou— € (©) A generator is delivering 60% of its maximurn Power to an infinite bus 07 Scanned with CamScannerSeatNo Enrolment No, GUJARAT TECHNOLOGICAL E G UNIVERSIT’ BE - SEMESTER-VII(NEW) EXAMINATION - SUMMER 7 Subject a : 7 Code:2170901 Date:1 6/05/2019 subject NamesInter Connected Power System ‘Time:02:30 PM TO 05:00 PM Total Marks: 70 Instructions: : 1._ Attempt all questions. 3, Make suitable assumptions wherever necessary. 3, Figures tothe right indicate full marks. sans Ql (a) Whats power system stability? Classify power system stability Hd& (b) How the buses in emer systems areclesified? — CA~ 6 04 (©) _ Explain need of oad low analysis, Derive si Joad flow equations. 7 tL h-3 ated as load bus? —9 a9 @ 04 2 (@) When the generator bus is rods to improve steady state stability. oe 5 hy 0 (b) Discuss various meth (©) The following figure ‘shows a simple 4-bus system. faeces 0.054501, | 0.154045 orofara i § Qo 0.1040.30 0.054)0.15 \ assumed negligible. “The shunt admittances a all the Busts ar that the line shown dotted is nol ‘connected. 1) Find YBUS assuming ‘YBUS if the line shown 2) What modifications inecd to be carried out in dotted is connected? oR ssis connected toaninfnitebus 07 rine of total reactance of 0.5 Pu tia constant is H=5 MW- negligible of natural 75% of its (© Asynchronous generator of reactance 12 bor VE. pu) through wansforne and ‘The generator no load voltage iS 1.2 puand its in gMVA. The resistance and ‘machine damping may be assumed The system frequency is 50 HZ Calculate the frequen: oscillations if the generator 18 Toaded 10 (i) 60% and Gi oreximum power iit. — CM~ Gi & Scanned with CamScannerQ3 Q3 Q4 Q4 Qs Qs (a) (b) © (a) b) (©) (a) (b) © (@) () © (a) (b) © (a) () © Oonwt S 03 fuel cost and penalty factor with its eo ation penalty fact it fuel Iso explain the Explain Incremental Te power system al Ein ‘automatic load ee es ye 0 importance of regional aes Mr plant are given BY ; osts for The incremental fuel c ‘t ae ~ —_. ae 4. 2o012P,+8 and 2= 75+ =0.002F, ' oe Sata \d varies from i total loa: Assuming both units are operating at all times, that Toads on each unit are 200 01150 MW, and that maximum and minimum loads on each wn tobe 550 and 100 MW, respectively. Find the ineerental fel cost of plant and the allocation of load between units for the mini various total loads. OR ee ; 3 Why bus admittance qua is used in Gauss Seidal instead of bus 0: impedance matrix, — Ca— - Epi speed governing mechanism for frequency control. = ce S w Explain various techniques to improve transient stability of a Va system, pw a3 Explain point by point method of stability in brief, ond Compare GS method of load flow study with FDLF method.—? 04 Explain the step by step method of solving swing equation stating clearly 07 the assumptions. —> Ch Cc OR Explain equal area criterion of stability. —_ch-C 03 ment is Multimachine stability? “List the assumptions made in ta multimachine stability studies, —» For the system shown in figure, find the voltage at the receiving bus atthe 07 Load Explain cascade tripping in power system, _ Q.3 (a) When penalty factor is to be considered for optimum generation 03 scheduling? —> On 4 (b) Explain cascading tripping. cnt 04 () A two bus system is shown in figure 3. If 100MW power is trai ferred 07 from plant | to the load; a transmission loss of 1OMW is incurred. Find the Joss in transmission fine. The system A is Rs. 25/MWh. The incremental fuel costs of the plants are given below: a 5 dC1 Spr 7 002+ 16 Rs/MWh dC2 _ 0.0472 +20 Rs/MWh Sep 00802 + 20 Rs oR Q.3° (a) State the advantages of interconnection in power system.— oat 03 @) Draw and explain the incremental fuel cost verss Doe! output 04 Characteristics of the generating unit in power plant. —? Cla= (0 Derive the transmission loss formula for a two Power plants system 07 ‘Connected with a transmission line. —> Ch ~ 4 5 4 (@)_Explain the importance of voltage contro! in owes system. 9 WA— 03 ower 04 nneration scenario in Gujarat from fuel used in p view. —) Ch-1 (b) Explain power get perates on full load at a frequency of 07 generation point of (©) A 100MVA, synchronous generator 0 SoH. The load is suddenly reduced to 50 MW. Due to time lag in governor ‘tern the steam valve begins to close afer 04 seconds, Determine the Shange in frequency that occurs inthis time. Take H= 5 KW-sec/KVA- UNS, OR mney control in power system. 03 Lows Q4 (a) Explain the importance of freque Scanned with CamScanner(b)_ Give difference between the fat frequency control and selective frequency 04 control. — An-S -$ (©) Explain methods of voltage control for power system. — Oh: 07 Q5 (a) Explain the role of automatic voltage regulator in generator.-|_, % 4 (b) Draw and explain simplified transient generator model. (©) A 100 MVA, IIKV, 50 Hz four pole turbo generator is rotating at 07 yynchronous speed. Energy is stored in its rotor equal to 800 MJ. Find the nertia constant of the generator. Also determine the rotor acceleration, if the mechanical input is suddenly raised to 80 MW for an electrical load of 50 MW. Neglect mechanical and electrical losses. —>ch-5 C OR QS (a) State three assumptions made in solving the swing equation. > On-© 93, (©) Explain equal area criteria for sudden increase in mechanical input to 04 generator. _ 1, (©) Determine the operating power angle for a power system shown in figure 07 4.The generator is delivering 1.0 pu power to the infinite bus, All reactance areinpu —» CH-€. 7 j0.25 Figure 2 Plant 2 Plant 1 Load SOO j0.05 Infinite bus jo.4 ~ TOOT Figure 4 feaeeeenee Scanned with CamScanner