Whether you are new to the industry or are well seasoned and want to review some of the basic information that you learned in the past, these courses and lessons will clearly outline what you are looking for. “Power Systems Electric” is On-Line training that bridges the gaps between textbook theories and practical power systems experience. As a retired electrical engineer who has gone through the experience of developing a career in electrical power systems, I know how frustrating it can be to try and find the answers, so I put together these courses that I feel would have been a major help to me in my development. I have also taken suggestions from students of what they would like to see in addition to these courses which I have given live in person.

Basic Electrical Learning

For those new to the industry, there is a beginner’s group of courses that cover the “Fundamentals of Electricity ” including DC and AC Circuit Analysis. These lessons examine such basics as Ohm’s Law, Series, and Parallel Circuits. The first, and perhaps most important, relationship between current, voltage, and impedance, “Ohm’s Law”, and its relevance to Series and Parallel Circuits. Subsequently, this will lead to the development of Kirchhoff’s Laws as they help to further analyze Network Analysis & Metering Circuits.

Conductors and Insulators are investigated along with their connected components, Capacitors, Inductors, and how they are influenced by Electromagnetism.

Alternating Current (AC – an electric current that periodically reverses direction) is the form in which electric power is delivered to businesses and residences, and it is the form of electrical energy that consumers typically use when they plug kitchen appliances, televisions, fans, and electric lamps into a wall socket.

The abbreviations AC and DC are often used to mean simply alternating and direct, as they are applied to current or voltage.

These AC courses deal specifically with sinusoidal waveforms and will provide the student with the basic understanding of working with circuits involving Alternating Current, which includes sinusoidal waveforms, vectors & phasors, reactance & impedance of R,L,C circuits, as they relate to the basic laws and theorems of electricity. This includes working with AC Power, Power Factor, Resonance, Complex Numbers, Reactance, and Impedance

Advanced Electrical Learning

These Courses involve subjects such as “Short Circuit Analysis for HV Three-Phase Systems ” which introduces the student to the basic concepts of fault studies on a high voltage three-phase system. System modeling is then used in order to aid in this process, with the ability to move between asymmetrical and symmetrical systems. With hey Searle and extensive study of “Per Phase” & “Per Unit” methodologies system faults are analyzed with the use of symmetrical components.

“A Per-Unit System ” is the expression of system quantities as fractions of a defined base unit quantity. Calculations are simplified because quantities expressed as per unit do not change when they are referred from one side of a transformer to the other.

In these courses, you will learn exactly what Per Unit Analysis is, the main advantages of using it, how manufacturers of equipment use and rate their products, and the technique of converting to and from the Per Unit system.

Several examples of working with Per Unit are demonstrated in this crisp clear presentation. When you finish you will have a though understanding of this subject.

It is important for all power engineers and technicians to be familiar with the concept of Per Unit as it is being used and referred to every day in power flow, short circuit evaluation, and motor starting studies.

The method of “Symmetrical Components ” is used to simplify asymmetrical three-phase voltages and current analysis by converting the unbalanced system into two sets of balanced phasors and a set of single-phase phasors, or symmetrical components. These sets of phasors are called the positive, negative, and zero sequence components.

An understanding of this method is essential for the understanding of fault analysis and modern-day protection schemes. These courses will provide you with the knowledge to comprehend the concept and how it is applied.

Supplemental Electrical Lessons

In all power electrical analyses, the student will encounter special Trigonometric and Mathematical identities and equations. This site contains special supplemental lessons that zero in on those identities and equations. For example, there are lessons that take you from the “Fundamentals of Trigonometry ” to the more sophisticated requirements in electrical engineering. As you work and study in electrical engineering you are going to run into proofs and equations that are based on trigonometry. A good example of this is when studying AC current, voltage, and impedance calculations, phasors or vectors are used and combined mathematically. Further adventures into complex power will also require a knowledge of trig functions and identities. As a student of this course, you will be introduced to these or at least re-introduced to these that may have been long since forgotten.
In mathematics, “The Derivative of a Function ” of a real variable measures the sensitivity to change of the function value (output value) with respect to a change in its argument (input value). Derivatives are a fundamental tool of calculus. For example, the derivative of the position of a moving object with respect to time is the object’s velocity: this measures how quickly the position of the object changes when time advances.

Specialized Electrical Lessons

Specialized lessons include the “Protection & Control(P & C)” principles of high voltage stations. HV Bus Differential Protection is studied along with restrictions due to CT saturation & mismatch and its solution, “Restraint Differential Protection”.

High Voltage Circuit Breakers are examined as to the various Types (Oil, Vacuum, Air Blast, SF6), their Controls as well as the introduction of potential transformers & current transformers, and their use in conjunction with the relevant instruments such as ammeters, voltmeters, watt meters, and energy meters.

Other lessons include the study of “Transformers ” including core construction along with losses, cooling, and mitigation techniques. Three-phase transformer configurations are studied along with harmonic distortion, CT saturation, and on-load tap-changer problems and how these problems are dealt with. Over-current and restraint differential transformer protection is developed along with a look at some examples of ” Old School relays” as well as modern IDE (intelligent Electrical Devices) relays.

Transformer Connections: (Y – Y; Delta – Delta; Y – Delta; Delta – Y & Y – Zag Zig) are examined along with Transformer Clock System Vector Nomenclature.

Lastly, there is a special section dedicated to “Single and Three-Phase Metering “, including old analog and new digital kilowatt-hour meters.

Conclusion

Regardless of whether or not you are new to the industrial power system, you’ll find what you’re looking for on this site in the way of training. In order to review or select any of these courses, left-click on any of the blue highlighted hyperlinked words of this posting or on “14 Courses Available” from the top menu of the landing page. All of the courses have a free introduction

As a bonus and in the way of a thank you, for your interest in PSPT’s WEB (and Blog) page, I’m making available my 50-page “Electrical Power” crib sheets. These were prepared for use with my courses that are available on this site. There is one section associated with each course and is extremely valuable while viewing the course, as well as a recall of the pertinent formulas and information after the fact. The contained information is also useful during any technical career as a quick reference from time to time. Simply click here or on the picture to the right to be taken to where you can download this item.

August 11, 2024

Blog #21 - Sinusoidal Waves & RMS Values

August 11, 2024/ Graham VanBrunt

This video is part of my series on alternating current. In this video, we are going to define RMS values. You will find this topic along with others in my course entitled Basic Fundamentals of AC Circuit Analysis. You can access this and my other courses on my stand store at this web address.

As we communicate the value of voltage and current with others in the industry of electrical power, we have to ask ourselves how useful are using any of the terms and is there some way of measuring the values that is the most useful way. That question was asked and answered a long time ago and the answer was the RMS values.

Before just jumping to the definition of RMS, which by the way is mathematically related proportionally to amplitude peak, peak to peak, average and mean average values, let's go through some logical steps to get there. Starting with two simple circuits, one DC, one AC. That is, each with the same load but one driven by DC source and the other driven by an AC source.

When we close the switch on the DC circuit, the bulb will light with an intensity that is dependent on the resistance, RL, of the light and the DC current.

Now let's close the switch and adjust the AC current to the light bulb with the same Intensity. That is to say both loads, both lights consume the same average power. So we now ask ourselves what is that AC current?

We can come to the conclusion that if the two bulbs light to the same brightness, that is they draw the same amount of power and it is reasonable to consider the current IAC to be in some ways equivalent to the current IDC. So what is that value of AC?

It would be useful if there was some meaningful way to calculate it. So let's go there. If an AC supply is connected to a component of resistance, say R, the instantaneous power dissipated is given by the power equation I squared R. If we plot I2, the instantaneous current, which itself is a sine wave, it is always positive because plus I times plus I is positive and negative I times negative I is positive. It does go to zero but never negative.

Remember that the instantaneous power dissipated is given by the equation power equals I2R. The peak or maximum value of I2 is shown here and labeled I2 max. The mean or average value of I2 is I2 max divided by two.

So the average value of power is, I will call it PAV is equal to I2max over 2RL. We just saw from the previous slide that the average power consumed in the circuit is given by this equation which is equal to the maximum value of the current squared over two times the resistor.

Let's define a current that when used to calculate power gives us the average power. In other words, when that current, let's call it Idefined for now, is squared and multiplied by RL gives us the average power.

But the defined or I2defined is also equal to I2max over two. Therefore, the square root of the mean current equals that defined current.

So we just discovered that what the value of Idefined is equal to I max divided by root two…and we call this current IRMS…or root mean square and it is 0.707 the value of the maximum current.

This is another more useful way to describe AC quantities, voltage and current. And of course it can be converted directly to amplitude peak or peak to peak or average just by multiplying by a scaling factor. However, we use RMS values for current and voltage.

We can directly calculate the average power from these root mean square quantities.

This video is part of my electrical technical information series. In this series, I will be covering essential topics to help you understand electrical systems.Be sure and stay tuned as I will also, from time to time, be reviewing electrical products that in my opinion are worthy of paying attention to.

This address https://bit.ly/3UGjBIg will give you access to the supplier of the aforementioned type products. It is also a connection to obtain a free copy of my 24 page three phase transformer workbook which will serve as a quick reference and reminder of technical calculations that you may need. This address of course is case sensitive.

One of those amazing and versatile products is the EcoFlow Delta Pro Ultra which can be modified to suit any homeowners needs operating virtually silent and when paired with the EcoFlow smart home panel 2 is extremely versatile. The EcoFlow home panel 2 ties any and all of your standby power equipment together and will control them efficiently. It will even control your connection to the utility grid to make sure you're only using the least expensive power switching to your standby power during those expensive time of use rates.

In order to view the full range of EcoFlow products and obtain a free copy of my three phase transformer workbook check into this web address https://bit.ly/3UGjBIg and simply provide your email address which will guide you to the browse the full extent of their products. There is no cost or commitment for viewing and by providing your email address it will allow me to keep you posted on future videos courses and EcoFlow products.