Electronics You Might Not Have Learned In College: Lesson 8 - High Voltage AC Transmission, AC Substations and Three Phase Power

In Electronics You Might Not Have Learned In College: Lesson 8 - High Voltage AC Transmission, AC Substations and Three Phase Power, you'll learn ...

• The structure and operation of high voltage AC transmission systems within modern power grids.
• The principles governing voltage transformation, power flow, and transmission efficiency in AC systems.
• The design, components, and functions of substations in electrical power networks.
• How to evaluate and manage technical factors such as power factor, reactive power, and transmission losses in three-phase systems.

Overview

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Credit: 4 CPD

Length: 53 pages

In this lesson, we learn a little about the Battle of the Currents and the decision to go with AC power because it was easier than DC to transform to high voltages for transmission over long distances. We study losses caused by high currents and why power is transmitted at such high voltages. We also hear about how to convert AC voltage to RMS power.

We discuss the phase angle between voltage and current and how it reduces delivered power. Knowledge of this helps to understand why we install huge capacitors in substations to balance out inductive loads. We also learn that high power is much more efficiently transmitted using high voltage rather than high current.

How transformers convert voltage and amperage is introduced and how power is conserved when voltage is being transformed. We learn about transformer polarity and how they are marked. We also are informed about eddy and core losses in transformers and how they are reduced.

We delve into the world of large distribution transformers and how their insulators and bushings are designed and made. We also discuss the main classification parameters for large transformers and how they are used in power transmission.

Then multiphase power and a little of its history is introduced. We discuss how and why three phase power took over most of the power transmission industry. We go into depth on how three phase power is generated and also how three-phase transformers work. Then we learn the concepts of Y and delta connected three phase circuits and how they are connected. Also, the standard voltages used for distribution and transmission of power are introduced.

We then look at the parts that make up high voltage transmission towers before discussing how substations are used to support the power grid and how they are constructed. We look at the parts that make up substations and how they are interconnected.

We introduce the problem of skin effect in power transmission and also losses due to corona effects in high voltage lines. We discuss the advantages and disadvantages of HVDC (high voltage direct current) power lines and how they could be used to mitigate some of the skin effect problems.

We cover the many power substations that are essential to the grid. We discuss unplanned switching events (line failures) and what backup power might be needed. We also cover traction substations for railways, emergency mobile substations, and how locations for substations are selected to add to the grid.

Safety around substations is discussed before talking about switch gear in substations and grid control rooms, substation heavy transformers, and maintenance of high voltage substations. Finally, we end up with the modernization and automation of substations.

While we see the massive infrastructure of power transmission throughout the world, most of us outside the electrical engineering world don’t understand the reasons behind its design and complexity. This course provides coverage of all these topics to different degrees. After completion, the student should have at least a basic knowledge of these many areas of power transmission.

Specific Knowledge or Skill Obtained

This course teaches the following specific knowledge and skills:

• The historical development of AC power systems and the significance of the War of the Currents in establishing modern transmission standards
• The technical and economic rationale for transmitting electrical power at high voltages to reduce current and minimize I²R losses
• The calculation and practical meaning of RMS voltage and current in sinusoidal AC waveforms
• The relationship between phase angle, real power, reactive power, apparent power, and power factor in AC circuits
• The role of capacitor banks and reactors in correcting power factor and improving transmission efficiency
• The application of fundamental power equations, including P = V × I × cos θ and Ploss = I²R, to real-world transmission scenarios
• The operating principles of transformers, including turns ratio effects on voltage and current and the preservation of energy
• The configuration and operation of three-phase generation and transformer connections, including delta and wye systems
• The structure and components of high voltage transmission lines, including conductors, insulators, towers, and considerations such as skin effect and corona
• The functions, classifications, and operational considerations of substations, including switching, protection, automation, safety, and maintenance practices

Certificate of Completion

You will be able to immediately print a certificate of completion after passing a multiple-choice quiz consisting of 24 questions. CPD credits are not awarded until the course is completed and quiz is passed.