IEEE 399 – Recommended Practice for Industrial and Commercial Power Systems Analysis

IEEE 399 is commonly known as the Brown Book in the Color Book series. The Brown Book supplements the rest of the color book series. Its practical and general treatment of power system analysis theory makes it as a good reference for engineers on the techniques applied to the computer-aided analysis of electric power systems in industrial plants and commercial buildings.

The abstract of this standard states

This Recommended Practice is a reference source for engineers involved in industrial and commercial power systems analysis. It contains a thorough analysis of the power system data required, and the techniques most commonly used in computer-aided analysis, in order to perform specific power system studies of the following: short-circuit, load flow, motorstarting, cable ampacity, stability, harmonic analysis, switching transient, reliability, ground mat, protective coordination, dc auxiliary power system, and power system modeling.

In Chapter 2 of the Brown Book. it outlined the scope of power system analysis.

Load flow analysis
To determine the voltage, current, active, and reactive power and power factor in a power system. It is an excellent tool for system planning.It provide conditions that may cause equipment overloads or poor voltage levels. It can be used to optimize the size and location of capacitors for power factor improvement.It is also useful in determining system voltages on conditions such as sudden applied or disconnected loads.
Short-circuit analysis
To determine the magnitude of fault currents flowing throughout the power system at various time intervals after a fault occurs.This is done for various types of faults (three phase, phase-to-phase, double-phase-to-ground, and phase-to-ground) at different locations throughout the system. The information is used to select fuses, breakers, and switchgear ratings in addition to setting protective relays.
Stability analysis
Stability is the ability of a power system, containing two or more synchronous machines, to continue to operate after a change occurs on the system.
Motor-starting analysis
The starting current of ac motors is about six times normal full load current when starting across the line. The motor terminal voltage may drop excessively. Motor-starting torque varies directly as the square of the applied voltage, the motor may not have enough starting torque to accelerate up to running speed. Running motors may stall from excessive voltage drops. This 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.
Harmonic analysis
Harmonics can affect other loads due to voltage distortion. The voltage distortion caused by the harmonics is a function of both the system impedance and the amount of harmonic current injected. If the system impedance is low, the voltage distortion is usually negligible in the absence of harmonic resonance. However, if harmonic resonance prevails, intolerable harmonic voltage and currents are likely to result.
Switching transients analysis
Severe switching transients will cause malfunctioning breakers or switches
Reliability analysis
Reliability and cost are essential in selecting an optimum design for a power system. A reliability index is the probability that a device will function without failure over a specified time period. This is represented by the MTBF (Mean Time Between Failure) of the power system components.
Cable ampacity analysis
Current-carrying capacity (ampacity) of power cables in installations determine the maximum conductor operating temperature. This calculations IS extremely complex due to many considerations.
Ground mat analysis
During ground-fault (earth-fault) conditions, the flow of fault current will result in voltage gradients within and around the fault and nearby earth and ground surface. Properly designed grounding system limits this voltage gradient and can be tolerated by the human body.
Protective device coordination analysis
A protection scheme in a power system minimizes 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. A properly coordinated system minimizes interruptions by isolating the faulted portion of the system.
DC auxiliary power system analysis
DC emergency power is used for circuit breaker control, protective relaying, inverters, instumentation, emergency lighting, communications, annunciators, fault recorders, and auxiliary motors. Computer aided studies of dc power systems analysis has allowed a more rapid and rigorous analysis of these systems compared to earlier manual techniques.

About the Author

Ver Pangonilo
A Filipino Engineer, Registered Professional Engineer of Queensland (RPEQ) - Australia and Professional Electrical Engineer (PEE) - Philippines with extensive experience in concept select, front-end engineering, HV & LV detail design, construction and commissioning of Hazardous and Non-Hazardous Area electrical installations in water and waste water pipeline and pumping facilities, offshore platforms, hydrocarbon process plants and pipelines including related facilities. Hazardous area classification and design certification (UEENEEM015B, UEENEEM016B, UEENEEM017B).
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