Power System Studies - Overview

Power System Analysis

The planning, design, and operation of a power system requires continual and comprehensive analyses to evaluate the system performance and to establish the effectiveness of alternative plans for system expansion. The planning, design, and operation of industrial and commercial power systems require several studies to assist in the evaluation of the initial and future system performance, system reliability, safety, and the ability to grow with production and/or operating requirements.

The studies most likely to be needed are Load flow studies, Short-circuit studies, Motor-starting studies, Protection Coordination studies, Arc Flash Studies, Transient Stability studies, Harmonic analysis studies.

?Load Flow Study:

A load flow study is a type of analysis performed on a power system to determine the steady-state voltages, currents, and power flows within the system. This study is also known as a power flow study. Load flow studies are a powerful analytical tool for power systems, providing valuable information on the system's voltage, current, active and reactive power, continuous equipment loading, power factor. Standards: IEEE 399-1997, IEEE 3002.2 -2018

?Short Circuit Study:

Short-circuit studies are done to determine the magnitude of the prospective currents flowing throughout the power system at various time intervals after a fault occurs. The magnitude of current flowing through the system after a fault varies with time until it reaches the steady state. The short circuit study gives the magnitude and duration of the short circuit current, Minimum & Maximum short circuit current. Standards: IEC 60909, IEC 61363, IEEE 551, IEEE 3002.3-2018

Motor Starting Study:

Motor starting studies are an analysis of the behavior and performance of an electric motor when it is started. The starting current of motors is several times of normal full load current. Motor-starting torque varies directly as the square of the applied voltage. If the terminal voltage drop is excessive, the motor may not have enough starting torque to accelerate up to running speed. Running motors connected in the system may stall from excessive voltage drops. The study can help select the best method of starting, the proper motor design, or the required system design for minimizing the impact of motor starting on the entire system. Standards: IEEE 3002.7 - 2018

Protection & Coordination Study:

A protection and coordination study is an analysis of the protection system used to safeguard electrical power systems from abnormal operating conditions such as short circuits and overloads. The objective of a protection scheme in a power system is to minimize hazards to personnel and equipment while allowing the least disruption of power service. Coordination studies are required to select or verify the clearing characteristics of devices such as fuses, circuit breakers, and relays used in the protection scheme. Standards: IEEE 242-2001, IEEE 3004 series

?Arc Flash Study:

An arc flash study is an analysis of the potential for arc flash incidents in an electrical power system. Arc flash incidents can occur when an electrical fault causes a sudden release of energy in the form of an electrical arc, which can produce intense heat, light, and pressure waves that can cause severe burns, injuries, and damage to equipment. Arc flash study helps to identify potential hazards associated with arc flashes, and to recommend safety measures that can be taken to mitigate these hazards.?Standards: IEEE 1584-2018, NFPA 70E- 2018

Transient Stability Study:

The ability of a power system, containing two or more synchronous machines, to continue to operate after a change occurs on the system is a measure of its stability. Transient stability is the ability of the system to remain in synchronism under transient conditions, i.e., faults, switching operations, etc. The study is performed to ensure that the system can maintain stable and reliable operation during such disturbances. This study investigates the system dynamic responses and stability limits of a power system before, during, and after system changes or disturbances. Standards: IEEE P3002.9-2018

Harmonic Analysis Study:

Harmonic analysis is the process of analyzing the harmonic distortion present in an electrical power system. Any devices with nonlinear voltage-current characteristics generate harmonics. The main sources of harmonics in industrial and commercial power systems are static power converters used as rectifiers for various industrial processes and for other applications such as adjustable/variable speed drives, uninterruptible power system (UPS), chargers, switched-mode supplies, static frequency converter, cycloconverters, etc. Arc furnaces and saturated magnetic devices are also harmonic sources. The Study can determine the effect of the harmonic contributions from nonlinear loads on the voltages and currents in the power system and also help in sizing and locating capacitors or passive filters for minimizing the effect of harmonics and optimizing system performance. Standards: IEEE 519, IEEE 3002.8-2018