Description : A 10-bus power system consists of four generator buses indexed as G1, G2, G3, G4 and six load buses indexed as L2, L2, L3, L4, L5, L6. The generator-bus G1 is connected ... of non linear equations required for solving the load flow problem using Newton-Raphson method in popular form is________.
Last Answer : 14
Description : In a load flow problem solved by newton-Raphson method with polar coordinates, the size of the Jactobian is 100 × 100. If there are 20 PV buses in addition to PQ buses and a slack bus, the total number of buses in the system is_____
Last Answer : 61
Description : A power system has 100 buses including 10 generator buses. For the load flow analysis using Newton-Raphson method in polar coordinates, the size of the Jacobian is a) 189x189 b) 100x100 c) 90x90 d) 180x180
Last Answer : a) 189x189
Description : A network containing 50 buses in which 10 are the voltage control buses, 6 are the generator buses. Find the size of the Jacobian matrix. a) 84*84 b) 83*83 c) 34*34 d) 33*33
Last Answer : b) 83*83
Description : Which of the following quantities are to be calculated for generator bus a) P and V b) V and δ c) δ and Q d) Q and P
Last Answer : c) δ and Q
Description : Mention the various types of buses in power system with specified quantities for each bus.
Last Answer : • Load bus or PQ-bus (P and Q are specified- Voltage magnitude and angle are to be obtained) • Generator bus or voltage controlled bus or PV bus (P and V are specified- Voltage angle and Q are to be obtained)
Description : What is the need for slack bus in power flow analysis.
Last Answer : The slack/swing bus is needed to account for transmission line losses. In a power system the total power generated will be equal to sum of power consumed by loads and losses. In a power ... power are not specified for slack bus. They are estimated through the solution of load flow equations.
Description : Specified quantities of load bus are a) P and Q b) V and δ c) P and δ d) Q and V
Last Answer : a) P and Q
Description : For load flow studies, what are the quantities specified at load bus are. a) P and V b) P and Q c) V and δ d) δ and Q
Last Answer : b) P and Q
Description : When will the generator bus is treated as load bus.
Last Answer : If the reactive power of a generator bus violates the specified limits then the generator bus is treated as load bus.
Description : In a load flow analysis of a power system, the load connected at a bus is represented as a) Constant current drawn from the bus b) Constant impedance connected at the bus c) Voltage and frequency dependent sources at the boss d) Constant real and reactive power drawn from the bus
Last Answer : d) Constant real and reactive power drawn from the bus
Description : In power system, if a voltage controlled bus is treated as a load bus then which one of the following limits would be violated? a) Voltage b) Active power c) reactive power d) Phase angle
Last Answer : a) Voltage
Description : In load flow studies of a power system, a voltage control bus is specified by a) Real power and reactive power b) Reactive power and voltage magnitude c) Voltage and voltage phase angle d) Real power and voltage magnitude
Last Answer : d) Real power and voltage magnitude
Description : Determine the correctness or otherwise of the following Assertion [a] and the Reason [r]. Assertion: Fast decoupled load flow method gives approximate load flow solution because it uses several assumptions. Reason: Accuracy ... the correct reason for [a]. c) [a] is false and [r] is true.
Last Answer : c) [a] is false and [r] is true
Description : or accurate load flow calculations on large power systems, the best method is a) N-R method b) G-S method c) Decoupled method d) all of the above
Last Answer : a) N-R method
Description : Define voltage-controlled bus and load bus.
Last Answer : LOAD BUS A bus is called PQ bus or load bus when real and reactive components of power are specified for the bus. In a load bus the voltage is allowed to vary within permissible limits ... constant using automatic voltage regulator, we can specify constant PGi and | Vi | for these buses.
Description : What technique is used to solve load flow problems using Z-bus (Bus impedance matrix)?
Last Answer : The formulation of load flow problem using Zbus employs Diakoptics techniques which is actually the piecewise solution of the power system problem by using tearing off technique.
Description : Discuss the effect of acceleration factor in the load flow solution algorithm.
Last Answer : An acceleration factor is a value that can be used to speed up the convergence and reduce the number of required alteration in a Gauss Seidel method of power flow analysis .Very high or very ... trial and error load flow analysis. A generally recommended value of the acceleration factor is 1.6.
Description : What is the need for load flow analysis.
Last Answer : The load flow study of a power system is essential to decide the best operation of existing system and for planning the future expansion of the system. It is also essential for designing a new power system.
Description : What is the information that are obtained from a load flow study.
Last Answer : • The magnitude and phase of bus voltages, real and reactive power flowing in each line and the line losses. • The load flow solution also gives the initial conditions of the system when the transient behavior of the system is to be studied.
Description : Which of the following matrix is used for load flow studies? a) null matrix b) Unit matrix c) Z bus matrix d) Y bus matrix
Last Answer : d) Y bus matrix
Description : A 1000 × 1000 bus admittance matrix for an electric power system has 8000 non-zero elements. The minimum number of branches (transmission lines and transformers) in this system are _____ (up to 2 decimal places)
Last Answer : Ans: 3500.00
Description : Advantage of Gauss-Seidel method is a) applicable for large power system network b) calculation time for each iteration is less c) number of iterations are less d) all of the above
Last Answer : b) calculation time for each iteration is less
Description : A 4 bus power system consists of 4 transmission lines, then find the sparsity of Y bus matrix? a) 0.75 b) 0.25 c) 0.4 d) 0.5
Last Answer : b) 0.25
Description : For n bus power system size of Y bus matrix is a) n*n b) (n-1)*(n-1) c) (n-1)*(n-2) d) (n-2)*(n-2)
Last Answer : a) n*n
Description : The voltage of a particular bus can be controlled by controlling the a) Active power of the bus b) Reactive power of the bus c) Phase angle d) All of the above
Last Answer : b) Reactive power of the bus
Description : What are the four quantities that are associated with each bus in a system?
Last Answer : • Real Power • Reactive Power • Voltage magnitude • Phase angle of voltage
Description : In a 4 bus,4×4 Y bus matrix the number of non zero elements are 12. Find the number of transmission lines? a) 8 b) 4 c) 2 d) 5
Last Answer : b) 4
Description : If sparsity of a 5 bus transmission line is 0.4. Find the number of transmission lines? a) 6 b) 5 c) 4 d) 3
Last Answer : b) 5
Description : Explain Flat Voltage start.
Last Answer : In iterative methods of load flow solution, the initial voltages of all buses except slack bus are assumed as 1+j0 p.u. This is referred to as flat voltage start.
Description : What are the advantages of FDLF method.
Last Answer : FDLF method is faster, simple to program, more reliable and requires less memory than NR load flow method. FDLF method requires more iteration than N-R method, but requires less time per iteration.
Description : What is jacobian matrix?
Last Answer : The Jacobian matrix gives the linearized relationship between small changes in voltage angle or voltage magnitude with a small changes in real and reactive power.
Description : What are the disadvantages of NR method.
Last Answer : • The programming is more complex. • The memory requirement is more. • Computational time per iteration is higher due to large number of calculations per iteration.
Description : Mention any three advantages of N-R method over G-S method.
Last Answer : • The N-R method has quadratic convergence characteristic and so convergence faster than G-S method. • The number of iterations for convergence is independent of the size of the system in N-R method. • In N-R method the convergence is not affected by the choice of slack bus.
Description : The value of off diagonal elements is a) sum of admittances connected at bus j b) which is connected between bus i and bus j with positive sign c) which is connected between bus i and bus j with negative sign d) sum of admittances connected at bus i
Last Answer : c) which is connected between bus i and bus j with negative sign
Description : um of the elements of row i equal to shunt admittances connected to bus i. If this summation is zero, indicates there is no a) shunt admittance b) mutual coupling c) both 1 and 2 d) none of the above
Last Answer : c) both 1 and 2
Description : Normally Z bus matrix is a a) null matrix b) sparse matrix c) full matrix d) unit matrix
Last Answer : full matrix
Description : When the generator buses are treated as load bus.
Last Answer : If the reactive power constraints of a generator bus violates the specified limits then the generator is treated as load bus.
Description : A bus disconnect link is used to isolate _____________. A. one bus bar from another B. the generator circuit breaker from the bus C. different phases from the equalizer connection D. positive and negative buses from the neutral
Last Answer : Answer: B
Description : 25 buses are running between two places P and Q. In how many ways can a person go from P to Q and return by a different bus? a) 300 b) 625 c) 600 d) 650
Last Answer : c) 600
Description : Which among the following means of transport in India carries maximum number of passengers during a year? (1) International water transport (2) Indian Railways (3) Ashok Leyland buses (4) Telco buses
Last Answer : (2) Indian Railways Explanation: Indian Railways (reporting mark IR) is an Indian state-owned enterprise, owned and operated by the government of India through the Ministry of Railways. It is one of the world's largest ... ,000 mi) of track over a route of 65,000 km (40,000 mi) and 7,500 stations.
Description : There are 312, 260 and 156 students in class X, XI and XII respectively. Buses are to be hired to take these students to a picnic. Find the maximum number of students who can sit in a bus if each bus takes equal number of students (a) 52 (b) 56 (c) 48 (d) 63
Last Answer : (a) 52
Description : Pick up the correct statement from the following: (A) The difference of latest occurrence time and earliest expected time, is called slack (B) The activities connecting the events having zero slack, lie on the critical path (C) The critical path consumes the maximum time (D) All the above
Last Answer : (D) All the above
Description : As shown in the illustration, when the 'speed control' system is in 'SPLIT' _______________. EL-0096 A. Relays #1, #5 and #8 are not used B. the 'slew rated controller' is grounded through Relay ... E/P converters' are bypassed and air is fed directly to the governors via the 'load sharing valve'
Last Answer : Answer: C
Description : A two-phase generator is connected to two 90Ω load resistors. Each coil generates 120 V ac. The value of current flowing through the common neutral line will be: A. 1.33 A B. 1.88 A C. 2.66 A D. 1.77 A
Last Answer : A two-phase generator is connected to two 90Ω load resistors. Each coil generates 120 V ac. The value of current flowing through the common neutral line will be: 1.77 A
Description : Steps taken by the Government of India to control air pollution include (a) compulsory PUC (Pollution under control) certification of petrol driven vehicles which tests for carbon monoxide and ... trucks (d) compulsory mixing of 20% ethyl alcohol with petrol and 20% biodiesel with diesel.
Last Answer : (a) compulsory PUC (Pollution under control) certification of petrol driven vehicles which tests for carbon monoxide and hydrocarbons
Description : A shunt generator running at 1000 r.p.m. has generated e.m.f. as 200 V. If the speed increases to 1200 r.p.m., the generated e.m.f. will be nearly?
Last Answer : 200V/E2 = 1000/1200 E2= 240 V
Description : What are the different types of buses in a power system?
Last Answer : The buses of a power system can be classified into three types based on the quantities being specified for the buses, which are as follows: a. Load bus or PQ bus (P and Q are specified) b. Generator bus ... P and V are specified) c. Slack bus or swing bus or reference bus (|V| and δ are specified)
Description : For a 15-bus power system with 3 voltage controlled buses, the size of Jacobian matrix is
Last Answer : For a 15-bus power system with 3 voltage controlled buses, the size of Jacobian matrix is 25 x 25
Description : What are the main sources of power supply to 6.6 kV buses?
Last Answer : a. Unit transformer which steps down the generated voltage to 6.6 kV from the generator. b. Start up transformer, which steps down the grid voltage to 6.6 kV.