Harmonics in Electrical Systems Online Course

This video lesson explains what makes up dirty power in an electrical system.  After viewing this lesson a student will be able to:

1. Explain what makes up dirty power.

2. List the causes of dirty power.

3. Describe the difference between a steady state disturbance and a short term disturbance.

4. Understand that harmonics are only one component of what makes dirty power.

In this video, the sub components or "frequencies" that make up the harmonic composite waveform are described. The sequence or "rotation" of each frequency is discussed.  After viewing this lesson a student will be able to:

1. List common harmonic frequencies generated by non-linear loads.

2. Understand that each harmonic frequency has a sequence associated with it (positive, negative and zero sequence).

3. Describe the effect of a negative sequence harmonic on an induction motor.

4. Describe the effect of negative and positive rotating harmonics on distributions systems.

5. Understand that triplen harmonics do not have a phase rotation and cause current to add in neutrals.

In this video, triplen harmonics are discussed.  The cause of the triplen harmonic, the effect on electrical equipment and solutions to deal with triplens are discussed. .  After viewing this lesson a student will be able to:

1. List the type of load that causes triplen harmonics.

2. Understand that triplens do not have a phasor rotation.

3. Described how triplen harmonics cause current to add in neutral conductors.

4. Explain how triplen harmonics are dealt with.

This lesson outlines some of the test equipment available to measure harmonics in electrical systems.  After completing this lesson a student will:

1. Know of the different types of electrical test equipment that can be used to measure harmonics in an electrical system.

2. Understand the differences between the various classes of meters and their limitations.

This lesson demonstrates the use of a clamp-on meter used to measure total harmonic distortion in an electrical system.  After completing this lesson a student will:

1. Know that total harmonic distortion or THD can be measured using a clamp-on amp meter.

2. Explain how the dual display mode differs from the single display mode when measuring voltage and current THD with an Amprobe ACD-41PQ meter.

3. Compare the accuracy of a THD measurement using a clamp on meter to a harmonics scopemeter.

This lesson explains the basics of oscilloscopes and how to setup an industrial scopemeter in order to obtain first readings.  After completing this lesson a student will:

1. Understand the oscilloscope vertical "Y"axis readings and horizontal "X" axis readings.

2. Understand volts per division and time per division.

3. Understand the importance of setting of an industrial scopemeter correctly in order to get an overview measurement of voltage and current.

4. Be aware of current and voltage probe polarity and understand the import of correct phasing when taking scope measurements.

This lesson shows how to use an industrial scopemeter to measure harmonics in a single phase power system.  After completing this lesson a student will:

1. Be capable of measuring harmonic current and voltages in a single phase power circuit using a Fluke 125B Industrial scopemeter.

2. Understand how to set up the correct measurement probe polarity.

3. Be capable of viewing harmonic subcomponents and associated values by using cursers in the harmonics measurement window.

4. View the KF value in harmonics mode.

This lesson provides a basic overview of a 3-phase power quality analyzer.  After completing this lesson a student will:

1. Gain a basic understanding of the capabilities of a 3-phase power quality meter.

2. Understand that these meters are designed to record and store data over long periods of time, in order to provide power trending analysis.

3. Know that these meters can be controlled remotely by software and that the software makes it easier to use the meters.

This lesson lists methods used to correct harmonic problems in individual loads, and larger systems that deliver harmonic current to varying loads.  After completing this lesson a student will:

1. Understand the difference between an individual harmonic solution and a system harmonic solution.

2. List available harmonic mitigating solutions for individual loads.

3. List available harmonic mitigating solutions for systems.

4. Explain the difference between an active harmonic filter and a passive harmonic filter.

This video lesson outlines the design characteristics of K-rated transformers. The lesson also explains the purpose of installing K-rated transformers. After completing this lesson a student will be able to:

1. Select a K-rated transformer for a specific non-linear load type.

2. List the design characteristics of K-rated transformers.

3. Understand the basic design intent of K-rated transformers with respect to delivering harmonic load current.

4. Explain the purpose of installing a K-rated transformer.

This video lesson explains the use of reactors with variable speed drives.  The lesson demonstrates the benefits of installing a reactor. After completing this lesson a student will be able to:

1. Understand how a line reactor reduces harmonics and improves the efficiency of a variable frequency drive.

2. List the differences between line, DC and load reactors with respect to variable frequency drives.

3. Follow electrical diagrams that contain line, DC bus and load reactors.

This video lesson provides an overview of the IEEE Standard for Harmonic Control in Electric Power Systems.  After completing this lesson a student will:

1. Understand important terms applied to harmonic voltage and current limits such as:

• Point of common coupling (PCC).

• Total demand distortion (TDD).

• Short circuit ratio.

• Total harmonic distortion (THD).

• Maximum demand load current.

  2. Know the difference of how voltage and current distortion limits are applied to electrical systems.

  3. Know where the recommended voltage and current limits are applicable in an electric power system.