Utility Distribution Systems

This course is self-paced, so you don’t need to be logged in at any specific time. You can get started immediately after you enroll and the course materials will remain in your account with minimum guaranteed access for 12 months (1 year) after enrollment.

In the first week we look at understanding basic drivers of utility distribution system design and operation. 1) In Distribution System Objectives, we discuss how distribution systems should serve loads with adequate voltage and frequency; meet reliability, resiliency and power quality goals; provide a platform for DER; be designed and operated with a primary emphasis on safety; meet environmental and aesthetics goals; and be designed with the lowest total owning cost. 2) In Distribution System Loads, we look at impacts of customer loads on system design and operations; resistive, inductive, and capacitive components of load; demand, energy, and power factor; demand factor and coincidence factor; different types of utility customers; customer load profiles; and customer classes and class load profiles. 3) In 3) Distributed Energy Resources (DER) on distribution, we look at the common types of DER on utility systems and utility challenges with DER on distribution.

In this week, we discuss the basic equipment for Transmitting and Transforming electric power. 1) In Overhead Lines and Underground Cables, we cover overhead line construction types, common distribution conductor materials, considerations in overhead conductor selection, principal overhead conductor characteristics, underground cable applications, cable insulation types, application considerations of distribution cables, and overhead versus underground distribution. 2) In Transformers, we look at the function of transformers, the application of transformers in power systems, substation transformers, three-phase and single-phase distribution transformers, and wye and delta configurations of three-phase transformers.

In Week 3, we look at basic types and components of system architectures. We look at distribution substations, distribution feeders, nominal voltage levels, three-phase and single-phase circuits, and typical circuit loadings. We discuss feeder primary architectures, including radial, radial with ties, and looped. In Secondary Systems, we look at secondary voltage levels for residential and commercial, and distributed secondary networks. We discuss the impacts of overhead and underground on architectures, and dual feeds with transfer switches for customers with high reliability requirements.

The focus in Week 4 is Voltage Monitoring and Control on utility distribution systems, and how reactive power, voltage control, and real power losses are inter-related. We cover reactive power requirements and sources, distribution voltage standards, voltage drop and causes, and the causes of real power losses. We look at the equipment that is applied - load tap changers, voltage regulators, and fixed and switched shunt capacitors - to improve voltage, supply reactive power, and reduce real power losses. We also cover the impacts of DER and particularly solar power, on voltage and reactive power.

The focus on week 5 is a basic understanding of overcurrent protection on distribution system design and operation. In the first part we take a look at short-circuits, including system faults, their causes, and their impacts. Building on this, we look at the goals of distribution system overcurrent protection, and the application of equipment to accomplish the goals, including circuit breakers, reclosers, sectionalizers, and fuses. A brief overview of the importance and principals of protection coordination is provided.

In week 6, we look at the important topic of distribution system reliability. The different outage causes on distribution systems is discussed, and the impacts on customers is reviewed. Distribution reliability indices for measuring the impact on customers is discussed, including SAIFI, SAIDI, and CAIDI. An overview of common reliability improvements methods is also covered.

This is our last module but you still have access to the all of course materials for 12 months (1 year), so keep working and you'll be able to complete the course at your own pace. After your year of access expires you can optionally extend access with a HeatSpring Membership. Enjoy the course and keep in touch!