What is transient state stability limit?

1 Answer

Answer :

The transient state stability limit is the max. power that can be transmitted by a machine to a receiving system without loss of synchronism.In steady state the power transferred by synchronous machine is always less than the steady state stability limit.

Related questions

Description : what is transient stability limit ?

Last Answer : The transient stability limit is the max power that can be transmitted by a machine to a fault or a receiving system during a transient state without loss of synchronism.The transient stability limit is always less than the steady state stability limit.

Description : Define transient stability?

Last Answer : The transient stabilitymis defined as the abilitymof a system to remain stable for large disturbance.

Description : What is steady state state stability limit?

Last Answer : The steady state stability limit is the max. power that can be transferred by a machine toa receving system without loss of synchronism.

Description : Define stability?

Last Answer : The stability of a system is defined as the ability of power system to return to stable operation when it is subjected to a disturbance. 68. Define steady state stability The stady statenstability is defined as the ability of a system to remain stable for small disturbance.

Description : Define stability study.

Last Answer : Stability studies are performed in order to ensure that the system remains stable following a severe fault or disturbance

Description : The transient state stability limit is always (A) Greater than the steady state stability limit. (B) Smaller than the steady state Stability limit. (C) Equal to the steady state stability limit. (D) The two are not related.

Last Answer : The transient state stability limit is always Smaller than the steady state Stability limit.

Description : The steady state stability limit as compared to the transient state stability limit is always

Last Answer : The steady state stability limit as compared to the transient state stability limit is always Greater

Description : Which of the following statements is true?  (1) steady-state stability limit is greater than transient stability limit  (2) steady-state stability limit is equal to transient stability ... made regarding the equality or otherwise of the steady-state stability limit and transient stability limit

Last Answer : Which of the following statements is true?  (1) steady-state stability limit is greater than transient stability limit  (2) steady-state stability limit is equal to transient ... made regarding the equality or otherwise of the steady-state stability limit and transient stability limit

Description : Define equal area criterion?

Last Answer : The equal area criterion for stability states that the system is stable if the area under pvs angle curve reduces to zero at some value of angle.

Description : Define critical clearing time and critiacal clearing angle

Last Answer : The critical clearing angle is the max. allowable change in the power angle before clearing the fault, without loss of synchronism. The critical clearing time can be defined as thw max. time delay that can be allowed to clear a fault without loss of synchronism.

Description : Define power angle

Last Answer : The power angle is defined as the angular displacement of the rotor from synchronously rotating referance frame.

Description : Define swing curve?

Last Answer : The swing curve is the plot between the power angle and time. It is usually plotted for a transient state to stydy the nature of variation in angle for a sudden large disturbance.

Description : What is meant by fault calculations

Last Answer : The fault condition of a power system can be dived into subtransient, transient and steady state periods. The currents in the various parts of the system and in the fault are different in ... for various types of faults at various locations in the system are commenly reffered as fault calculations.

Description : Name any two methods of reducing short circuit current/ By providing neutral reactance.

Last Answer : By introducing a large value of shunt reactance between buses.

Description : What is symmetrical and unsymmetrical fault?

Last Answer : The fault is called symmetrical fault if the fault current is equal in all the phases. The fault is called unsymmetrical fault if the fault current is not equal in all the phases.

Description : List the various types of series and shunt fault?

Last Answer : Shunt faults are, Line to ground fault line to line fault, double line to ground fault, three phase fault. Series faults are, One open conductor fault Two open conductor fault

Description : How are faults are classified?

Last Answer : The faults are classified as shunt and series faults. The shunt faults are due to short circuits in conductors and the series faults are due to oped conductors.

Description : Why fault accurs in a power system?

Last Answer : The fault occur in a power system due to insulation failure of equipments, flashover of lines initiated by a lightning stroke, due to permanent damage to conductors and towers

Description : What is meant by a fault?

Last Answer : A fault in a circuit is any failure which interferes with the normal flow of current. The faults are associated with abnormal change in current, voltage and frequency of the power systwm. The faults may ... to sence the faults to isolate the faulty part from the healthy part in the event of fault.

Description : What is off nominal turns ratio?

Last Answer : When the voltage or turns ratio of a transformer is not used to decide the ratio of base KV then its voltage ratio is called off nominal turns ratio. Usually the voltage ratio of regulating transformer will be off nominal ratios.

Description : What are the disadv. Of N-R method?

Last Answer : The programming is more complex The memory requirement is more

Description : What are the adv. Of N-R method?

Last Answer : The N-R method is faster, more reliable and the results are accurate. Requires less no. of iterations Suitable for large size system

Description : What is Jacobian matrix?

Last Answer : How the elements of Jacobian matrix are computed. The matrix formed from the first derivatives of load flow equations is called Jacobian matrix. The elements of Jacobian matrix will change in ... t a unknown variable and then evaluating the first derivatives using the solution of previous iteration

Description : How approximations is performed in Newton Raphson method?

Last Answer : In N-R method, the set of nonlinear simultaneous equations are approximated to a set of linear simultaneous equations using tailors series expansion and the terms are limited to first order approximation.

Description : What are the advantages of Guass sedal methoa?

Last Answer : Calculations are simple and so the programming task is lesses. The memory requirement is less Useful for small systems 55 What are the disadvantages of Guass seidal method? Requires large no. ... to reach converge Not suitable for large systems Convergence time increases with size of the system

Description : What will be the reactive power and bus voltage whan the generator bus is treated as load bus.

Last Answer : When the generator bus is treated as load bus, the reactive power of the bus is equated to the limit it has violated, and the previous iteration value of bus voltage is used for calculating current iteration value.

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 : What is meant by flat voltage start.

Last Answer : In iterative methods of load flow solution, the initial voltages of all buses exept slack bus are assumed as 1+j0 pu.This is reffered as flat voltage profile.

Description : Discuss the effect of acceleration factor in load flow study.

Last Answer : The acceleration factor is a real quantity and it modify the magnitude of voltage alone.

Description : What are the iterative methods mainly used for solution of load flow study.

Last Answer : The Guass sedal method and Newton Raphson method are the two iterative methods.

Description : What are the operating constraints imposed in the load flow studies?

Last Answer : The operating constraints imposed in load flow studies are reactive power limits for generator buses and allowable change in magnitude of voltagefor load buses.

Description : What is the need for slack bus

Last Answer : The slack 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 system only ... for losses. Since the losses are unknown the real and reactive power are not specified for slack bus.

Description : What is PQ bus?

Last Answer : A bus is called PQ 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. 46. What is swing bus? Abus ... it is required for accounting line losses. Usually one of the generator bus is selected as swing bus.

Description : Define voltage controlled bus?

Last Answer : A bus is called voltage controlled bus if the magnitude of volte\age and real power are specified for it. In a voltage controlled bus the magnitude of the voltage is not allowed to change.

Description : What are the quantities associated with each bus ina system?

Last Answer : Each bus in a power system is associated with four quantities and they are real power, reactive power, magnitude of voltage, and phase angle of voltage.

Description : What is the need for load flow study.

Last Answer : The load flow study of a power system is essential to decide the best operation existing system and for planning the future expansion of the system. It is also essential for designing the power system.

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.

Description : What is load flow or power flow study?

Last Answer : The study of various methods of solution to power system network is reffered to as load flow study. The solution provides the voltages at various buses, power flowing in various lines and line losses.

Description : What is meant by positive, negative and zero sequence reactance.

Last Answer : The reactance diagram of a power system, when formed using positive, negative and zero sequence reactances are called positive, negative and zero sequence reactance diagram resp.

Description : What is meant by positive, negative and zero sequence impedance.

Last Answer : The impedance of the circuit element for positive, negative and zero sequence component currents are called positive, negative and zero sequence impedances resp.

Description : What are sequence impedance and sequence networks?

Last Answer : The sequence impedances are the impedances offered by the devices for the like sequrnce component of the current. The single phase equivalent circuit of a power system consists of impedances to current of any one sequence is called sequence network

Description : What are zero sequence components?

Last Answer : The zero sequence components of a three phase unbalanced vectors consists of 3 vectors of equal magnitude and with zero phase displacement from each other.

Description : What are negative sequence components?

Last Answer : The negative sequence components of a three phase unbalanced vectors consists of three vectors of equal magnitude displaced from each other by 120 degree in phase and having the phase sequence opposite to that of the original vectors.

Description : What are positive sequence components?

Last Answer : The positive sequence components of a three phase unbalanced vectors consists of three vectors of equal magnatude, displased from each other by 120 in phase and having the same phase sequence as the original vectors.

Description : Write the symmetrical components of three phase system.

Last Answer : 1.positive sequence components 3. negative sequence components. 4. zero sequence components.

Description : What are symmetrical components?

Last Answer : An unbalanced system of N related vectors can be resolved into N systems of balanced vectors. The N sets of balanced vectors are called symmetrical components.

Description : Write the four ways of adding an impedance to an existing system so as to modify bus impedance matrix.

Last Answer : 1. Adding a branch of impedanceZb from a new bus p to the referance bus. 2. Adding a branch of impedance Zb from a new busp to an existing bus. 3. Adding a branch of impedance Zb from an existing busq to the referance bus. 4. Adding a branch of impedance Zb between two existing buses h and q.

Description : What are the methods available for forming bus impedance matrix.

Last Answer : 1. Form the bus impedance matrix and then take its inverse to get bus impedance matrix. 2. Directly form the bus impedance matrix from the reactance diagram. This method utilizes the techniques of modifications of existing bus impedance matrix due to addition of new bus.

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 bus imbedance matrix?

Last Answer : The matrix consisting of driving point impedances and transfer impedances of the network of a power system is called bus impedance matrix.