ArtsAutosBooksBusinessEducationEntertainmentFamilyFashionFoodGamesGenderHealthHolidaysHomeHubPagesPersonal FinancePetsPoliticsReligionSportsTechnologyTravel

Power Harmonics – Sources and Solutions

Updated on May 10, 2021
tamarawilhite profile image

Tamara Wilhite is a technical writer, an industrial engineer, a mother of two, and a published sci-fi and horror author.

What Causes Power System Harmonics?

The electrical power provided by a utility arrives on a high voltage line with alternating current. The power is stepped down in voltage and may or may not be converted to direct current for use inside the building. Power system harmonics are caused by magnetizing impedances of devices like the step-down transformers that connect utility lines to individual buildings.

Alternating current systems naturally produce some harmonics. Three-phase power systems produce odd numbered harmonics; 3-phase power systems often generate three levels of harmonics. Voltage and current variation is normally a sinusoidal wave. Power system harmonics alters this wave form, creating spikes and surges that can damage sensitive electronics downstream.

Power transfomers like this naturally create some harmonics in the power system.
Power transfomers like this naturally create some harmonics in the power system. | Source

Impact of Power System Harmonics

Industrial equipment containing power electronic components such as variable speed motor controllers are the most sensitive to power harmonics. When the voltage supplying a capacitor has significant variation, the capacitor in turn varies the current it puts out. If the power system harmonics vary the voltage by 5%, the capacitor receiving this voltage will vary its current output by at least 5%. Power system harmonics may overload uninterruptable power supplies, also called UPS. Extreme variations in current flow can overload capacitors, burning them out.

Harmonic currents cause power losses. These power losses result in excess heat that shortens its operating life. In extreme situations, current and voltage fluctuations can pose a fire hazard. However, utilities tend to monitor their power quality, and major power customers take steps to reduce power system harmonics.

Methods to Reduce Harmonics

Power system harmonics can be reduced by installing harmonic filters or harmonic suppressing reactors. Active filters receive a harmonic load and then neutralize it. Active filters can adjust their output. Active filters also reduce the risk of an overload. Active filters may be installed at any point in the power system, and multiple filters can be installed in the same power system.

Passive filters regulate harmonics using series of resistors, inductors and capacitors. Passive filters do not require electricity to operate. Hybrid filters are a hybrid of active and passive filters. Passive and hybrid filters can be connected in parallel. Increasing the size of the capacitors in the power system reduces the impact of power system harmonics.

At the Point of Common Coupling, or PCC where the incoming utility power line connects with a step-down transformer to convert power for usage inside of a building, reactive devices like capacitor banks can be used to control the power harmonics. Installing capacitors can reduce the harmonics on the power line, but they can also cause resonance on other harmonic frequencies. Resonance is reduced by installing anti-harmonic coils in series with the capacitors.

Power System Harmonics Standards

IEEE standard 519 provides recommendations for measuring power system harmonics. IEEE 519 also sets recommended limits on the voltage and current coming into a building. These limits reduce the risk of damage to capacitors, inductors, controlling devices and sensitive electronics that can be shorted or overloaded by power system fluctuations.

An Uninterruptable Power Supply or UPS designed for a sinusoidal power flow cannot provide sufficient voltage when the actual load is based on the voltage peaks of a system experiencing harmonics. IEC standard 60892 outlines an equation for determining a weighted harmonic factor for harmonic voltage. IEC Standard 61000-3-6 sets emission limits for power system distortions in power system connections. IEC 61000-3-6 refers to this as Electromagnetic Compatibility or EMC.

Poor power harmonics interfere with the electronics receiving the power.
Poor power harmonics interfere with the electronics receiving the power. | Source

This website uses cookies

As a user in the EEA, your approval is needed on a few things. To provide a better website experience, uses cookies (and other similar technologies) and may collect, process, and share personal data. Please choose which areas of our service you consent to our doing so.

For more information on managing or withdrawing consents and how we handle data, visit our Privacy Policy at:

Show Details
HubPages Device IDThis is used to identify particular browsers or devices when the access the service, and is used for security reasons.
LoginThis is necessary to sign in to the HubPages Service.
Google RecaptchaThis is used to prevent bots and spam. (Privacy Policy)
AkismetThis is used to detect comment spam. (Privacy Policy)
HubPages Google AnalyticsThis is used to provide data on traffic to our website, all personally identifyable data is anonymized. (Privacy Policy)
HubPages Traffic PixelThis is used to collect data on traffic to articles and other pages on our site. Unless you are signed in to a HubPages account, all personally identifiable information is anonymized.
Amazon Web ServicesThis is a cloud services platform that we used to host our service. (Privacy Policy)
CloudflareThis is a cloud CDN service that we use to efficiently deliver files required for our service to operate such as javascript, cascading style sheets, images, and videos. (Privacy Policy)
Google Hosted LibrariesJavascript software libraries such as jQuery are loaded at endpoints on the or domains, for performance and efficiency reasons. (Privacy Policy)
Google Custom SearchThis is feature allows you to search the site. (Privacy Policy)
Google MapsSome articles have Google Maps embedded in them. (Privacy Policy)
Google ChartsThis is used to display charts and graphs on articles and the author center. (Privacy Policy)
Google AdSense Host APIThis service allows you to sign up for or associate a Google AdSense account with HubPages, so that you can earn money from ads on your articles. No data is shared unless you engage with this feature. (Privacy Policy)
Google YouTubeSome articles have YouTube videos embedded in them. (Privacy Policy)
VimeoSome articles have Vimeo videos embedded in them. (Privacy Policy)
PaypalThis is used for a registered author who enrolls in the HubPages Earnings program and requests to be paid via PayPal. No data is shared with Paypal unless you engage with this feature. (Privacy Policy)
Facebook LoginYou can use this to streamline signing up for, or signing in to your Hubpages account. No data is shared with Facebook unless you engage with this feature. (Privacy Policy)
MavenThis supports the Maven widget and search functionality. (Privacy Policy)
Google AdSenseThis is an ad network. (Privacy Policy)
Google DoubleClickGoogle provides ad serving technology and runs an ad network. (Privacy Policy)
Index ExchangeThis is an ad network. (Privacy Policy)
SovrnThis is an ad network. (Privacy Policy)
Facebook AdsThis is an ad network. (Privacy Policy)
Amazon Unified Ad MarketplaceThis is an ad network. (Privacy Policy)
AppNexusThis is an ad network. (Privacy Policy)
OpenxThis is an ad network. (Privacy Policy)
Rubicon ProjectThis is an ad network. (Privacy Policy)
TripleLiftThis is an ad network. (Privacy Policy)
Say MediaWe partner with Say Media to deliver ad campaigns on our sites. (Privacy Policy)
Remarketing PixelsWe may use remarketing pixels from advertising networks such as Google AdWords, Bing Ads, and Facebook in order to advertise the HubPages Service to people that have visited our sites.
Conversion Tracking PixelsWe may use conversion tracking pixels from advertising networks such as Google AdWords, Bing Ads, and Facebook in order to identify when an advertisement has successfully resulted in the desired action, such as signing up for the HubPages Service or publishing an article on the HubPages Service.
Author Google AnalyticsThis is used to provide traffic data and reports to the authors of articles on the HubPages Service. (Privacy Policy)
ComscoreComScore is a media measurement and analytics company providing marketing data and analytics to enterprises, media and advertising agencies, and publishers. Non-consent will result in ComScore only processing obfuscated personal data. (Privacy Policy)
Amazon Tracking PixelSome articles display amazon products as part of the Amazon Affiliate program, this pixel provides traffic statistics for those products (Privacy Policy)
ClickscoThis is a data management platform studying reader behavior (Privacy Policy)