If the reference bus is changed in two load flow runs with same system data and power obtained for

If the reference bus is changed in two load flow runs with same system data and power obtained for reference bus taken as specified P and Q in the latter run, the system losses 

A) Will be unchanged but complex bus voltages will change B) Will change but complex bus voltage remain unchanged C) As well as complex bus voltage will changed D) As well as complex bus voltage will be unchanged
by

1 Answer

Answer :

If the reference bus is changed in two load flow runs with same system data and power obtained for reference bus taken as specified P and Q in the latter run, the system losses Will be unchanged but complex bus voltages will change

by

Related questions

In load flow Study, a PV bus is treated as a PQ bus when

Description : In load flow Study, a PV bus is treated as a PQ bus when

Last Answer : Voltage at the bus becomes high 

In load flow analysis, the load connected at a bus is represented as?

Description : In load flow analysis, the load connected at a bus is represented as?

Last Answer : constant real and reactive powers drawn from bus

If a voltage-controlled bus is treated as load bus, then which one of the following limits would be

Description : If a voltage-controlled bus is treated as load bus, then which one of the following limits would be violated?   (a) Active power (b) Reactive power (c) Voltage (d) Phase angle 

Last Answer : If a voltage-controlled bus is treated as load bus, then which one of the following limits would be violated?   (a) Active power (b) Reactive power (c) Voltage (d) Phase angle 

A cylinder rotor generator delivers 0.5 pu power in the steady-state to an infinite bus through a transmission

Description : A cylinder rotor generator delivers 0.5 pu power in the steady-state to an infinite bus through a transmission line of reactance 0.5 pu. The generator no-load voltage is 1.5 pu and the infinite bus voltage is 1 pu. The ... fault at the generator terminal is  (A) 53.5 (B) 60.2 (C) 70.8 (D) 79.6

Last Answer : A cylinder rotor generator delivers 0.5 pu power in the steady-state to an infinite bus through a transmission line of reactance 0.5 pu. The generator no-load voltage is 1.5 pu and the ... clearing angle, in degrees, for a three-phase dead short circuit fault at the generator terminal is 79.6

A large AC generator, supplying power to an infinite bus, has a sudden short-circuit occurring at its terminals

Description : A large AC generator, supplying power to an infinite bus, has a sudden short-circuit occurring at its terminals. Assuming the prime mover input and the voltage behind the transient reactance to remain constant immediately after the fault, acceleration of the generator rotor is

Last Answer : A large AC generator, supplying power to an infinite bus, has a sudden short-circuit occurring at its terminals. Assuming the prime mover input and the voltage behind the transient reactance ... , acceleration of the generator rotor is inversely proportional to the moment of inertia of the machine

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

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

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

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

If a 5-bus test system contains 6 transmission lines and one transformer, how many non- zero elements are

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.

For optimum generator scheduling for different power plants, the minimum fuel cost is obtained when

Description : For optimum generator scheduling for different power plants, the minimum fuel cost is obtained when

Last Answer : For optimum generator scheduling for different power plants, the minimum fuel cost is obtained when The incremental fuel cost of each plant multiplied by the penalty factor is the same

Generally in a power system network, the load is represented as a :

Description : Generally in a power system network, the load is represented as a :  (A) Constant power in both load flow study and in stability study  (B) Constant power in load flow study and constant ... impedance in load flow study  (D) Constant impedance in both load flow study and in stability study

Last Answer : Generally in a power system network, the load is represented as a : Constant power in load flow study and constant impedance in stability study 

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_____

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

A 3-phase 11 kV generator feeds power to a constant power unity power factor load of 100 MW through a

Description : A 3-phase 11 kV generator feeds power to a constant power unity power factor load of 100 MW through a 3-phase transmission line. The line-to line voltage at the terminals of the machine is maintained constant at 11 kV. The per ... 11 kV is  (A) 100 MVAR (B) 10.1 MVAR (C) -100 MVAR (D) -10.1 MVAR

Last Answer : A 3-phase 11 kV generator feeds power to a constant power unity power factor load of 100 MW through a 3-phase transmission line. The line-to line voltage at the terminals of the machine is maintained ... load to increase the line-to-line voltage at the load terminals to 11 kV is -10.1 MVAR

At an industrial sub-station with a 4 MW load, a capacitor of 2 MVAR is installed to maintain the load power

Description : At an industrial sub-station with a 4 MW load, a capacitor of 2 MVAR is installed to maintain the load power factor at 0.97 lagging. If the capacitor goes out of service, the load power factor becomes (A) 0.85 (B) 1.00 (C) 0.80 lag (D) 0.90 lag

Last Answer : At an industrial sub-station with a 4 MW load, a capacitor of 2 MVAR is installed to maintain the load power factor at 0.97 lagging. If the capacitor goes out of service, the load power factor becomes  0.80 lag

A transformer has negative voltage regulation when its load power factor is

Description : A transformer has negative voltage regulation when its load power factor is   (1) Zero (2) Unity (3) Leading (4) Lagging

Last Answer : 0

Load compensation in power systems is a process to :

Description : Load compensation in power systems is a process to :  (A) Maintain better voltage profile (B) Increase short circuit capacity of the system (C) Generate required harmonics for loads like arc furnaces (D) Compensate for the line reactance

Last Answer : Load compensation in power systems is a process to : Maintain better voltage profile

Power station having Load factor = 70%, capacity factor = 50%, used factor = 60%, maximum demand = 20MW

Description : Power station having Load factor = 70%, capacity factor = 50%, used factor = 60%, maximum demand = 20MW then annual energy production is  (1) 122.8 GWh (2) 198.55 GWh (3) 128.2 GWh (4) 188.82 GWh

Last Answer : Power station having Load factor = 70%, capacity factor = 50%, used factor = 60%, maximum demand = 20MW then annual energy production is 122.8 GWh

A 3-phase, 11 kv, 50 Hz, 200 kW load has a power factor of 0.8 lag. ...

Description : A 3-phase, 11 kv, 50 Hz, 200 kW load has a power factor of 0.8 lag. A delta connected 3-phase capacitor is used to improve the power factor to unity. The capacitance perphase of the capacitor in micro-farads is?

Last Answer : A 3-phase, 11 kv, 50 Hz, 200 kW load has a power factor of 0.8 lag. A delta connected 3-phase capacitor is used to improve the power factor to unity. The capacitance perphase of the capacitor in micro-farads is 1.316.

A power station supplies the peak load of 60 Mw, 40 MW and 70 MW to three localities...

Description : A power station supplies the peak load of 60 Mw, 40 MW and 70 MW to three localities. The annual load factor is 0.50 p.u. and the diversity factor of the load at the station is 1.55. The maximum demand on the station and average load respectively will be 

Last Answer : A power station supplies the peak load of 60 Mw, 40 MW and 70 MW to three localities. The annual load factor is 0.50 p.u. and the diversity factor of the load at the station is 1.55. The maximum demand on the station and average load respectively will be 103.2 MW, 51.61 .

The yearly load duration curve of a power plant is a straight line...

Description : The yearly load duration curve of a power plant is a straight line. The maximum load is 750 MW and the minimum load is 600 Mw. The capacity of the plant is 900 MW. What is the capacity factor and utilization factor? 

Last Answer : 0.75, 0.83 is the capacity factor and utilization factor.

If transformer frequency is changed from 60 Hz, to 60 Hz the ratio of...

Description : If transformer frequency is changed from 60 Hz, to 60 Hz the ratio of eddy current loss 60 Hz to 50 Hz, at constant voltage will be?

Last Answer : If transformer frequency is changed from 60 Hz, to 60 Hz the ratio of eddy current loss 60 Hz to 50 Hz, at constant voltage will be 1.0.

Which of the following statement is not correct with reference to cron daemon in UNIX O.S? (A) The cron daemon is the standard tool for running commands on a predetermined schedule. (B) It starts when the system boots and runs as long as the system is up. (C) Cron reads configuration files that contain list of command lines and the times at which they invoked. (D) Crontab for individual users are not stored.

Description : Which of the following statement is not correct with reference to cron daemon in UNIX O.S? (A) The cron daemon is the standard tool for running commands on a predetermined schedule. (B) It starts ... command lines and the times at which they invoked. (D) Crontab for individual users are not stored.

Last Answer : (D) Crontab for individual users are not stored.

For a fixed value of complex power flow in a transmission line having a sending and voltage V, the real

Description : For a fixed value of complex power flow in a transmission line having a sending and voltage V, the real power loss will be proportional to  A) V B) v2 C) 1/V2 D)1/V

Last Answer : For a fixed value of complex power flow in a transmission line having a sending and voltage V, the real power loss will be proportional to 1/V2

The power flow problem mathematical model for a linear transmission network

Description : The power flow problem mathematical model for a linear transmission network (A) is non-linear (B) is linear (C) considers time variation of generation (D) does not consider tap-changing transformers

Last Answer : The power flow problem mathematical model for a linear transmission network is non-linear

What technique is used to solve load flow problems using Z-bus (Bus impedance matrix)?

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.

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

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

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

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

In reference with antireflection coating which of the following statement is true? A. Thickness of the film should be changed for light of same wavelength but different intensity B. Thickness of the film need not be changed for light of same wavelength but different intensity C. Thickness of the film should be increased for light of same wavelength but higher intensity D. Thickness of the film should be decreased for light of same wavelength but higher intensity

Description : In reference with antireflection coating which of the following statement is true? A. Thickness of the film should be changed for light of same wavelength but different intensity B. Thickness of ... D. Thickness of the film should be decreased for light of same wavelength but higher intensity

Last Answer : B. Thickness of the film need not be changed for light of same wavelength but different intensity

The sequence components of current of a single-phase load connected to a 3-phase system are

Description : The sequence components of current of a single-phase load connected to a 3-phase system are (A) equal positive and negative sequence components (B) equal positive, negative and zero sequence components (C) vector sum of sequence currents is zero (D) algebraic sum of sequence currents is zero

Last Answer : The sequence components of current of a single-phase load connected to a 3-phase system are equal positive, negative and zero sequence components

The operating torque of the upper induction disc-type element, or timer element, of an AC reverse power relay is obtained from ____________. A. the main bus B. a separate battery source C. line voltage D. electromagnets

Description : The operating torque of the upper induction disc-type element, or timer element, of an AC reverse power relay is obtained from ____________. A. the main bus B. a separate battery source C. line voltage D. electromagnets

Last Answer : Answer: D

What is the path from which data flow in a computer system is known as A) Car B) Bus C) Truck D) Road

Description : What is the path from which data flow in a computer system is known as A) Car B) Bus C) Truck D) Road

Last Answer : Answer : B

What are the information that are obtained from a load flow study.

Description : What are the information that are obtained from a load flow study.

Last Answer : The information obtained from a load flow study are magnatude and phase of bus voltages,real and reactive power flowing in each line and the line losses. T he load flow solution also gives the initial conditions of the system when the transient behaviour of the system to be studied.

What are the information that are obtained from a load flow study?

Description : What are the information that are obtained from a load flow study?

Last Answer : The information obtained from a load flow study are magnitude and phase angles of bus voltages, real and reactive power flowing in each line and 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.

What is the information that are obtained from a load flow study.

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.

An 8-pole alternator runs at 750 rpm and supplies power to a 6-pole induction motor which has a full load

Description :  An 8-pole alternator runs at 750 rpm and supplies power to a 6-pole induction motor which has a full load slip of 3 percent. The full load speed of the induction motor will be: A) 1000 rpm B) 920 rpm C) 950 rpm D) 970 rpm

Last Answer : An 8-pole alternator runs at 750 rpm and supplies power to a 6-pole induction motor which has a full load slip of 3 percent. The full load speed of the induction motor will be: 970 rpm

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

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

Load factor is the

Description : Load factor is the  (1) Ratio of maximum load on the station to sum of consumer's maximum load.  (2) Ratio of average demand to maximum demand.  (3) Factor used for increasing load.  (4) Reciprocal of (1).

Last Answer : Load factor is the Ratio of average demand to maximum demand. 

The load duration curve for unity load factor will be of

Description : The load duration curve for unity load factor will be of  (1) Rectangular shape (2) Triangular shape (3) L -shape (4) I -shape

Last Answer : The load duration curve for unity load factor will be of Rectangular shape

A 60 Hz, 320 km lossless line has Bending end voltage 1.0 p.u, The receiving end voltage on no load is

Description : A 60 Hz, 320 km lossless line has Bending end voltage 1.0 p.u, The receiving end voltage on no load is?

Last Answer : A 60 Hz, 320 km lossless line has Bending end voltage 1.0 p.u, The receiving end voltage on no load is 1.088 p.u.

A generating st ation has a maximum, demand of 20 mW, load factor of 60%,...

Description : A generating st ation has a maximum, demand of 20 mW, load factor of 60%, a plant capacity factor of 50% and a plant Use factor of 72%. What is the reserve capacity of the plant, if the plant, while running as per schedule, were fully loaded?

Last Answer : 5 MW is the reserve capacity of the plant, if the plant, while running as per schedule, were fully loaded.

A generating station has a maximum demand of 50 Mw, a load factor of 60%, a plant capacity factor...

Description : A generating station has a maximum demand of 50 Mw, a load factor of 60%, a plant capacity factor of 45% and if the plant while running as per schedule, were fully loaded. The daily energy produced will be

Last Answer : A generating station has a maximum demand of 50 Mw, a load factor of 60%, a plant capacity factor of 45% and if the plant while running as per schedule, were fully loaded. The daily energy produced will be 720 MW.

A consumer consume. 600 kWh per day at a load factor of 0.40....

Description : A consumer consumes. 600 kWh per day at a load factor of 0.40. If the consumer increases the load factor of 0.70 without increasing the maximum demand, what is the consumption of energy in kWh?

Last Answer : A consumer consume. 600 kWh per day at a load factor of 0.40. If the coneumer increases the load factor of 0.70 without increasing the maximum demand, 1050 kWh is the consumption of energy in kWh.

What is the maximum value of a load which consume 500 KWh per day at...

Description : What is the maximum value of a load which consume 500 KWh per day at a load factor of 0.40, if the consumer increases the load factor of 0.50 without increasing the maximum demand?

Last Answer : 52.08 kW is the maximum value of a load which consume 500 KWh per day at a load factor of 0.40, if the consumer increases the load factor of 0.50 without increasing the maximum demand.

An industrial consumer hall a daily load pattern of 2000 KW, 0.8 lag for...

Description : An industrial consumer hall a daily load pattern of 2000 KW, 0.8 lag for 12 Hra and 1000 kW UPF for 1J Hr. The load factor i= _____. 

Last Answer : An industrial consumer hall a daily load pattern of 2000 KW, 0.8 lag for 12 Hra and 1000 kW UPF for 1J Hr. The load factor i= 0.6 . 

What is swing bus(slack bus/reference bus)?

Description : What is swing bus(slack bus/reference bus)?

Last Answer : A bus is called swing bus when the magnitude and phase of bus voltage are specified for it. The swing bus is the reference bus for load flow solution and it is required for accounting for the line losses. Usually one of the generator bus is selected as the swing bus.

Precise control of reactive current flow entering the transmission and distribution systems can be minimized

Description : Precise control of reactive current flow entering the transmission and distribution systems can be minimized by using (A) synchronous condenser (B) static VAR capacitor (C) capacitor bank (D) thyristor switched reactor in parallel with capacitor

Last Answer : Precise control of reactive current flow entering the transmission and distribution systems can be minimized by using (A) synchronous condenser (B) static VAR capacitor (C) capacitor bank (D) thyristor switched reactor in parallel with capacitor

To remove an alternator operating in parallel with another unit from the main electrical bus, you must FIRST _________. A. adjust the power factor on both units B. set the desired voltage on the outgoing alternator C. open the circuit breaker on the outgoing alternator D. remove the load from the outgoing alternator

Description : To remove an alternator operating in parallel with another unit from the main electrical bus, you must FIRST _________. A. adjust the power factor on both units B. set the desired voltage on ... C. open the circuit breaker on the outgoing alternator D. remove the load from the outgoing alternator

Last Answer : Answer: D

Regarding an AC generator connected to the main electrical bus; as the electric load and power factor vary, a corresponding change is reflected in the generator armature reaction. These changes in armature reaction are compensated for by the __________ A. governor speed droop setting B. voltage regulator C. balance coil D. phase-balance relay

Description : Regarding an AC generator connected to the main electrical bus; as the electric load and power factor vary, a corresponding change is reflected in the generator armature reaction. These changes in ... . governor speed droop setting B. voltage regulator C. balance coil D. phase-balance relay

Last Answer : Answer: B