{"id":4381,"date":"2026-04-29T14:09:37","date_gmt":"2026-04-29T11:09:37","guid":{"rendered":"https:\/\/www.tkf.fi\/active-filters\/"},"modified":"2026-10-28T10:35:21","modified_gmt":"2026-10-28T07:35:21","slug":"active-filters","status":"publish","type":"page","link":"https:\/\/www.tkf.fi\/en\/active-filters\/","title":{"rendered":"Active filters"},"content":{"rendered":"\t\t
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Active filters<\/h1>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t
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Harmonic currents occur in electrical power systems due to nonlinear loads such as computers, frequency converters, and UPS systems. Harmonic currents cause, for example, increased losses and malfunctions in electrical equipment. An active filter is needed when the harmonic content in the power grid is so high that the harmonics may cause interference.<\/p>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t

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Power quality
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The active filter is designed for networks with high harmonic content to dynamically improve power quality. An active filter is a particularly effective solution when the network has harmonics of various orders (5th, 7th, 9th, 19th, etc). In addition, the harmonic levels may vary. An active filter produces a current opposite to each harmonic current, cancelling out the harmful harmonics. In addition, the active filter improves both the inductive and capacitive power factors. Any suspicion of high harmonic distortion should be verified through measurements.<\/p>\n<\/div>\n<\/div>\n<\/div>\n\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t

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Active filter
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– Compensation current: 40\u2013400 A
– The modular design also allows for compensation currents of over 400 A
– 3- or 4-wire version
– Voltage: 200\u2013690 V
– 50\/60 Hz
– Temperature: 40\u00b0C without a reduction in power; 55\u00b0C with reduced power
– Air- or water-cooled
– IP30, up to IP54 if necessary<\/p>\n\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t

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Harmonics<\/h2>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
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\n\t\t\t\t\t\t\t\t\t\nThe ideal electrical current and voltage waveforms are sinusoidal (BLACK<\/span>).<\/strong> Some electrical devices cause distortions in the sinusoidal waveform of the network. These distortions, shown in the blue curve, are called harmonics. Harmonics are multiples of the fundamental frequency: (DIFFERENT COLOURS<\/span>)<\/strong>. Harmonics add to the fundamental wave, causing a distorted sinusoidal wave (RED<\/span>)<\/strong>.\n\n\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t
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Harmonic sources<\/h3>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
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Well-known sources of harmonics include frequency converters, switch-mode power supplies, thyristor switches, electronics in homes and offices, UPS systems, LED lights, and discharge lamps.<\/p>\n\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t

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Disadvantages<\/h3>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
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The adverse effects of harmonics include increased interference in the network and in electricity users’ equipment, as well as a reduction in the load capacity of the equipment. Harmonics also cause meter readings to be inaccurate and lead to malfunctions in automation equipment and protective relays.<\/p>\n<\/div>\n\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t

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TKF's solutions are used at thousands of sites, ranging from office buildings to industrial facilities<\/h2>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
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Needs range from standard reactive power compensation to demanding applications that are critical to society. Hospitals (such as Tampere University Hospital and Satakunta Central Hospital in Finland), the Finnish Defence Forces, infrastructure projects (Helsinki Airport and the Helsinki metro), industry, real estate companies (VVO, Senate Properties), and electrical installations.<\/p>\n\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t

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Active filters Harmonic currents occur in electrical power systems due to nonlinear loads such as computers, frequency converters, and UPS […]<\/p>\n","protected":false},"author":1,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"site-sidebar-layout":"no-sidebar","site-content-layout":"","ast-site-content-layout":"full-width-container","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"disabled","ast-breadcrumbs-content":"","ast-featured-img":"disabled","footer-sml-layout":"","ast-disable-related-posts":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"default","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-4)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-4)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-4)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"footnotes":""},"class_list":["post-4381","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/www.tkf.fi\/en\/wp-json\/wp\/v2\/pages\/4381","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.tkf.fi\/en\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/www.tkf.fi\/en\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/www.tkf.fi\/en\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.tkf.fi\/en\/wp-json\/wp\/v2\/comments?post=4381"}],"version-history":[{"count":5,"href":"https:\/\/www.tkf.fi\/en\/wp-json\/wp\/v2\/pages\/4381\/revisions"}],"predecessor-version":[{"id":4768,"href":"https:\/\/www.tkf.fi\/en\/wp-json\/wp\/v2\/pages\/4381\/revisions\/4768"}],"wp:attachment":[{"href":"https:\/\/www.tkf.fi\/en\/wp-json\/wp\/v2\/media?parent=4381"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}