Engineering Fundamentals

Abstract: The fundamentals of electric power and electrical systems have remained unchanged for many years though technologies employed in electrical power systems have advanced greatly. Anyone responsible for any part of an electrical system relies on the fundamental relationships presented.

Abstract: Understanding the loads connected to an electrical system is an essential consideration when designing or operating said system. Determining the size of the equipment required, including fault interrupting devices, bus bars, conductors, and similar, is not just a summation of connected load nameplates. Herein, considerations and practices are presented to facilitate load planning to ensure adequate sizing is accomplished while not over-sizing and increasing electrical system infrastructure costs. Additional information on motor characteristics, motor load, sizing requirements and motor protection are found in the Fundamentals of Motor Control Design Guide.

Abstract: In addition to factors such as load planning, system voltage selection is a fundamental aspect of electrical system design. The utilization voltage of equipment can be accomplished with various distribution system voltages. Typical considerations include utility connections, rate tariffs, distances to loads, costs and others. Selecting the appropriate system voltage allows efficiencies while managing the capital and maintenance expenditures.

Abstract: The electrical point of interconnection with a utility can vary in voltage level whether it be secondary, primary, or transmission voltages. The reliability of an electrical system is directly affected by the system arrangement and the voltage level to which it is connected. Additionally, the need for redundancy or serviceability without a complete shutdown are also considerations when evaluating various system arrangements.

Abstract: System grounding considerations affect many aspects of an electrical system. Knowledge of the various types of system grounding and performance characteristics is critical when designing or operating an electrical system. The voltage, system arrangement, loads connected, and continuity of service drive grounding requirements and design choices.

Abstract: To protect personnel, equipment, and maintain continuity of service for an electrical system, protection or fault interrupting devices are required. Adequate system designs allow for the system to withstand and isolate faults while not causing additional damage and/or outages. System protection is paramount and must be understood by all persons interacting or responsible for electrical systems.