IBM Interview Questions and Answers

There are various types of faults in power system.

• Short circuit fault

• Open circuit fault

• Ground fault

• Overvoltage fault

• Undervoltage fault

• Overcurrent fault

• Underfrequency fault

• Overfrequency fault

Different sequence of current in SLG, LLG, LLLG faults.

• SLG fault has only one phase grounded, LLG fault has two phases grounded, LLLG fault has all three phases grounded

• In SLG fault, the sequence of current is positive-negative-zero, in LLG fault it is zero-positive-negative, and in LLLG fault it is zero-zero-zero

• These faults can cause damage to electrical equipment and must be quickly detected and resolved

Swing equations are used to model the behavior of power systems during transient events.

• Swing equations are a set of differential equations that describe the dynamics of power systems during transient events.

• They are used to model the behavior of generators, transformers, and other components in the power system.

• Swing equations take into account the mechanical and electrical properties of the system, as well as the power flow and voltage levels.

• They are important for analyzin...read more

Equal area criteria is a method to determine stability of power systems.

• It is used to analyze transient stability of power systems.

• It states that for a power system to be stable, the area of the power-angle curve during fault should be equal to the area of the power-angle curve after fault clearance.

• It helps in determining the critical clearing angle and time required for fault clearance.

• It is based on the assumption that the power system can be represented by a swing equatio...read more

Load flow can be solved using various methods.

• Gauss-Seidel method

• Newton-Raphson method

• Fast decoupled method

• DC load flow method

• AC load flow method

• Continuation power flow method

Motor EMF equations are mathematical equations that describe the relationship between the voltage generated by a motor and its speed and magnetic field.

• EMF equations are used to calculate the voltage generated by a motor as it rotates.

• The equations take into account the motor's speed, magnetic field strength, and number of turns in the coil.

• The EMF equations are important for designing and optimizing motors for specific applications.

• Examples of EMF equations include Faraday's...read more