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)

1 Answer

Answer :

Ans: 3500.00

Related questions

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 : 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 : 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 : 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 : 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 : 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 : 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 : Normally Z bus matrix is a a) null matrix b) sparse matrix c) full matrix d) unit matrix

Last Answer : full matrix

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 : 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 : 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 : 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 : 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 : 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 : Name the diagonal and off diagonal elements of bus admittance matrix.

Last Answer : The diagonal elements of bus admittance matrix are called self admittances of the buses and off diagonal elements are called mutual admittances of the buses.

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 : 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 : 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 : 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 : 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 : 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 : 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 : If a 5-bus test system contains 6 transmission lines and one transformer, how many non-zero elements are there in the system Y-bus ? (A) 25 (B) 12 (C) 11 (D) 19

Last Answer : If a 5-bus test system contains 6 transmission lines and one transformer, 19 non-zero elements are there in the system Y-bus.

Description : In power system, the maximum number of buses are a) Generator buses b) Load buses c) Slack buses d) P-V buses

Last Answer : b) Load buses

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 : What is bus admittance matrix?

Last Answer : The matrix consisting of the self and mutual admittances of the network of a power system is called bus admittance matrix.

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 : 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 : The diagonal elements of a nodal admittance matrix are strengthened by adding :  (A) Shunt capacitors (C) Generators (B) Shunt inductances (D) Resistive loads

Last Answer : A

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 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 : 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 : 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 : 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 : In which of the following transmission lines, the value of the Shunt admittance should be approximated to zero ? (A) A 66 kV 35 km long line (B) A 132 kV 200 km long line (C) A 220 kV 300 km long line (D) A 400 kV 500 km long line

Last Answer : In which of the following transmission lines, the value of the Shunt admittance should be approximated to zero ? (A) A 66 kV 35 km long line (B) A 132 kV 200 km long line (C) A 220 kV 300 km long line (D) A 400 kV 500 km long line

Description : Suppose transmission rate of a channel is 32 kbps. If there are ‘8’ routes from source to destination and each packet p contains 8000 bits. Total end to end delay in sending packet P is _____. a. 2 sec b. 3 sec c. 4 sec d. 1 sec

Last Answer : a. 2 sec

Description : In transmission line, which of the following is the first step in the procedure of using stub matching? A. Calculate stub susceptance. B. Calculate load admittance C. Connect stub to load D. Transform conductance to resistance

Last Answer : B. Calculate load admittance

Last Answer : The shunt admittance of a transmission line is given by Y = G + j ω C

Description : Name the diagonal elements and off diagonal elements of bus impedance matrix.

Last Answer : The diagonal elements of bus impedance matrix are called driving point impedances of the buses and off diagonal elements of bus impedance matrix are called transfer impedances of the buses.

Description : What is a six digit number that when divided by 1000 gives a number with no decimal places?

Last Answer : 100000

Description : SONET sends ________ frames per second A) 1000 B) 2000 C) 4000 D) 8000

Last Answer : 2000

Description : Calorific value of a typical dry anthracite coal may be around __________ Kcal/kg. (A) 1000 (B) 4000 (C) 8000 (D) 15000

Last Answer : (C) 8000

Description : Calorific value of coal middling generated in coal washeries during washing of coal may be around __________ Kcal/kg. (A) 1000 (B) 4000 (C) 6000 (D) 8000

Last Answer : (B) 4000