{"id":5793,"date":"2026-03-03T11:12:06","date_gmt":"2026-03-03T10:12:06","guid":{"rendered":"https:\/\/termocent.com\/?p=5793"},"modified":"2026-09-14T19:59:16","modified_gmt":"2026-09-14T17:59:16","slug":"partial-discharge-detection-acoustic-camera","status":"publish","type":"post","link":"https:\/\/termocent.com\/en\/blog\/partial-discharge-detection-acoustic-camera\/","title":{"rendered":"Partial-discharge detection with an acoustic imaging camera"},"content":{"rendered":"<div id=\"ez-toc-container\" class=\"ez-toc-v2_0_88 counter-hierarchy ez-toc-counter ez-toc-grey ez-toc-container-direction\">\n<div class=\"ez-toc-title-container\">\n<p class=\"ez-toc-title\" style=\"cursor:inherit\">Spis tre\u015bci<\/p>\n<span class=\"ez-toc-title-toggle\"><a href=\"#\" class=\"ez-toc-pull-right ez-toc-btn ez-toc-btn-xs ez-toc-btn-default ez-toc-toggle\" aria-label=\"Toggle Table of Content\"><span class=\"ez-toc-js-icon-con\"><span class=\"\"><span class=\"eztoc-hide\" style=\"display:none;\">Toggle<\/span><span class=\"ez-toc-icon-toggle-span\"><svg style=\"fill: #999;color:#999\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\" class=\"list-377408\" width=\"20px\" height=\"20px\" viewBox=\"0 0 24 24\" fill=\"none\"><path d=\"M6 6H4v2h2V6zm14 0H8v2h12V6zM4 11h2v2H4v-2zm16 0H8v2h12v-2zM4 16h2v2H4v-2zm16 0H8v2h12v-2z\" fill=\"currentColor\"><\/path><\/svg><svg style=\"fill: #999;color:#999\" class=\"arrow-unsorted-368013\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\" width=\"10px\" height=\"10px\" viewBox=\"0 0 24 24\" version=\"1.2\" baseProfile=\"tiny\"><path d=\"M18.2 9.3l-6.2-6.3-6.2 6.3c-.2.2-.3.4-.3.7s.1.5.3.7c.2.2.4.3.7.3h11c.3 0 .5-.1.7-.3.2-.2.3-.5.3-.7s-.1-.5-.3-.7zM5.8 14.7l6.2 6.3 6.2-6.3c.2-.2.3-.5.3-.7s-.1-.5-.3-.7c-.2-.2-.4-.3-.7-.3h-11c-.3 0-.5.1-.7.3-.2.2-.3.5-.3.7s.1.5.3.7z\"\/><\/svg><\/span><\/span><\/span><\/a><\/span><\/div>\n<nav><ul class='ez-toc-list ez-toc-list-level-1 ' ><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-1\" href=\"https:\/\/termocent.com\/en\/blog\/partial-discharge-detection-acoustic-camera\/#What_are_partial_discharges\" >What are partial discharges?<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-2\" href=\"https:\/\/termocent.com\/en\/blog\/partial-discharge-detection-acoustic-camera\/#Recent_case_identifying_a_corona-discharge_pattern\" >Recent case: identifying a corona-discharge pattern<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-3\" href=\"https:\/\/termocent.com\/en\/blog\/partial-discharge-detection-acoustic-camera\/#How_does_an_acoustic_camera_detect_partial_discharges\" >How does an acoustic camera detect partial discharges?<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-4\" href=\"https:\/\/termocent.com\/en\/blog\/partial-discharge-detection-acoustic-camera\/#Why_does_this_matter\" >Why does this matter?<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-5\" href=\"https:\/\/termocent.com\/en\/blog\/partial-discharge-detection-acoustic-camera\/#TERMOCENTs_diagnostic_capabilities\" >TERMOCENT&#8217;s diagnostic capabilities<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-6\" href=\"https:\/\/termocent.com\/en\/blog\/partial-discharge-detection-acoustic-camera\/#When_should_a_partial-discharge_inspection_be_considered\" >When should a partial-discharge inspection be considered?<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-7\" href=\"https:\/\/termocent.com\/en\/blog\/partial-discharge-detection-acoustic-camera\/#TERMOCENT_technical_diagnostics_for_electrical_installations\" >TERMOCENT: technical diagnostics for electrical installations<\/a><\/li><\/ul><\/nav><\/div>\n<h2><span class=\"ez-toc-section\" id=\"What_are_partial_discharges\"><\/span>What are partial discharges?<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>Partial discharges (PD) are localised electrical discharges that do not completely bridge the insulation between conductors. They can develop at weak points in insulation, around sharp edges of conductive components, in air voids, on contaminated surfaces or as materials age.<\/p>\n<p>One common type is corona discharge, which occurs in a strong electric field around high-voltage conductors.<\/p>\n<p>Although the phenomenon may initially appear minor, continued partial-discharge activity can contribute to:<\/p>\n<ul>\n<li>insulation degradation,<\/li>\n<li>increased energy losses,<\/li>\n<li>a greater risk of breakdown,<\/li>\n<li>equipment failure,<\/li>\n<li>fire risk.<\/li>\n<\/ul>\n<p><img decoding=\"async\" class=\"aligncenter wp-image-5033 size-full\" src=\"https:\/\/termocent.com\/wp-content\/uploads\/2026\/03\/2026.02.17_Wyladowania_niezupelne_htm_9eeb8eb0.jpg\" alt=\"partial-discharge inspection\" width=\"636\" height=\"955\" srcset=\"https:\/\/termocent.com\/wp-content\/uploads\/2026\/03\/2026.02.17_Wyladowania_niezupelne_htm_9eeb8eb0.jpg 636w, https:\/\/termocent.com\/wp-content\/uploads\/2026\/03\/2026.02.17_Wyladowania_niezupelne_htm_9eeb8eb0-200x300.jpg 200w\" sizes=\"(max-width: 636px) 100vw, 636px\" \/><\/p>\n<h2><span class=\"ez-toc-section\" id=\"Recent_case_identifying_a_corona-discharge_pattern\"><\/span>Recent case: identifying a corona-discharge pattern<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>During a recent measurement with a HIKMICRO AI76 acoustic imaging camera, the instrument classified the recorded partial-discharge pattern as corona (`Corona 100%`). The source was observed indirectly by analysing waves reflected from the ceiling above the equipment.<\/p>\n<p><img decoding=\"async\" class=\"aligncenter wp-image-5041 size-full\" src=\"https:\/\/termocent.com\/wp-content\/uploads\/2026\/03\/Termocent.png\" alt=\"acoustic imaging report for a partial-discharge inspection\" width=\"552\" height=\"810\" srcset=\"https:\/\/termocent.com\/wp-content\/uploads\/2026\/03\/Termocent.png 552w, https:\/\/termocent.com\/wp-content\/uploads\/2026\/03\/Termocent-204x300.png 204w\" sizes=\"(max-width: 552px) 100vw, 552px\" \/><\/p>\n<p>The measurement report recorded:<\/p>\n<ul>\n<li>maximum level: 39.0 dB,<\/li>\n<li>classification: Severe,<\/li>\n<li>frequency range: 20\u201348 kHz,<\/li>\n<li>measurement distance: 1.0 m,<\/li>\n<li>instrument model: AI76,<\/li>\n<li>discharge type returned by the instrument: Corona \u2014 100%.<\/li>\n<\/ul>\n<p><img decoding=\"async\" class=\"aligncenter wp-image-5045 size-full\" src=\"https:\/\/termocent.com\/wp-content\/uploads\/2026\/03\/2026.02.17_Wyladowania_niezupelne_htm_c35c6066.png\" alt=\"partial-discharge activity plotted against the 50 Hz voltage phase angle\" width=\"180\" height=\"91\" \/><\/p>\n<p style=\"text-align: center;\">The chart shows the distribution of discharge activity against the phase angle of the 50 Hz voltage waveform (0\u00b0\u2013360\u00b0).<\/p>\n<p>&nbsp;<\/p>\n<p><img decoding=\"async\" class=\"aligncenter wp-image-5049 size-full\" src=\"https:\/\/termocent.com\/wp-content\/uploads\/2026\/03\/2026.02.17_Wyladowania_niezupelne_htm_3e77defa.png\" alt=\"ultrasonic signal amplitude plotted over time\" width=\"290\" height=\"88\" \/><\/p>\n<p style=\"text-align: center;\">The chart shows the ultrasonic signal amplitude over time (0\u201345 ms).<\/p>\n<p>&nbsp;<\/p>\n<p><img decoding=\"async\" class=\"aligncenter wp-image-5053 size-full\" src=\"https:\/\/termocent.com\/wp-content\/uploads\/2026\/03\/2026.02.17_Wyladowania_niezupelne_htm_a9525ad3.png\" alt=\"signal-energy distribution in the 20 to 48 kHz band\" width=\"330\" height=\"91\" srcset=\"https:\/\/termocent.com\/wp-content\/uploads\/2026\/03\/2026.02.17_Wyladowania_niezupelne_htm_a9525ad3.png 330w, https:\/\/termocent.com\/wp-content\/uploads\/2026\/03\/2026.02.17_Wyladowania_niezupelne_htm_a9525ad3-300x83.png 300w\" sizes=\"(max-width: 330px) 100vw, 330px\" \/><\/p>\n<p style=\"text-align: center;\">The chart shows the distribution of signal energy within the 20\u201348 kHz band.<\/p>\n<p>&nbsp;<\/p>\n<p>The instrument&#8217;s PRPD analysis classified the recorded pattern as corona rather than a surface, floating or particle discharge. This classification forms part of the measurement evidence and must be interpreted together with the equipment, operating conditions and inspection context.<\/p>\n<p>The measurement was carried out without opening or interfering with the installation because the component had been sealed by the distribution system operator. The survey was non-invasive and used waves reflected from the ceiling above the affected equipment.<\/p>\n<h2><span class=\"ez-toc-section\" id=\"How_does_an_acoustic_camera_detect_partial_discharges\"><\/span>How does an acoustic camera detect partial discharges?<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>Partial discharges can emit ultrasonic waves outside the range of human hearing. An acoustic imaging camera:<\/p>\n<ul>\n<li>uses an array of MEMS microphones \u2014 136 in the AI76,<\/li>\n<li>processes the signal in real time,<\/li>\n<li>overlays an acoustic map on the visible image,<\/li>\n<li>supports discharge-pattern analysis and classification.<\/li>\n<\/ul>\n<p>Unlike a point ultrasonic detector, the camera can visualise the direction of an acoustic source across the scene. In suitable circumstances it can be used while the installation remains in operation, avoiding intrusive access to the inspected component. The safe method and operating state must always be agreed for the particular installation.<\/p>\n<p><img decoding=\"async\" class=\"aligncenter wp-image-5057 size-full\" src=\"https:\/\/termocent.com\/wp-content\/uploads\/2026\/03\/2026.02.17_Wyladowania_niezupelne_htm_1d20b76.gif\" alt=\"acoustic camera visualising a partial-discharge source\" width=\"804\" height=\"503\" \/><\/p>\n<h2><span class=\"ez-toc-section\" id=\"Why_does_this_matter\"><\/span>Why does this matter?<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>In this case, the instrument assigned the recorded event the `Severe` classification. This prompted consideration of:<\/p>\n<ul>\n<li>accelerated insulation degradation,<\/li>\n<li>an increased risk of failure,<\/li>\n<li>possible progression towards arcing,<\/li>\n<li>potential production downtime.<\/li>\n<\/ul>\n<p>For an industrial facility, an unresolved defect can have consequences including:<\/p>\n<ul>\n<li>costly downtime,<\/li>\n<li>damage to transformers or switchgear,<\/li>\n<li>disruption to the electricity supply.<\/li>\n<\/ul>\n<p>The classification is not a diagnosis on its own. It helps prioritise further technical assessment and the appropriate response.<\/p>\n<h2><span class=\"ez-toc-section\" id=\"TERMOCENTs_diagnostic_capabilities\"><\/span>TERMOCENT&#8217;s diagnostic capabilities<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>Ultrasonic imaging enables us to:<\/p>\n<ul>\n<li>locate an acoustic emission source where access and conditions permit,<\/li>\n<li>document the instrument&#8217;s severity indication,<\/li>\n<li>record the discharge-pattern classification,<\/li>\n<li>compare measurements over time where the inspection method and conditions are repeatable.<\/li>\n<\/ul>\n<p>This provides additional evidence for assessing the technical condition of electrical equipment.<\/p>\n<h2><span class=\"ez-toc-section\" id=\"When_should_a_partial-discharge_inspection_be_considered\"><\/span>When should a partial-discharge inspection be considered?<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>Acoustic partial-discharge inspections can be considered for:<\/p>\n<ul>\n<li>high- and medium-voltage switchgear,<\/li>\n<li>transformer stations,<\/li>\n<li>cable and overhead lines,<\/li>\n<li>metering and protection bays,<\/li>\n<li>installations operating in elevated humidity or dusty conditions,<\/li>\n<li>industrial facilities where continuity of production is critical.<\/li>\n<\/ul>\n<p>Potential benefits of acoustic partial-discharge diagnostics include:<\/p>\n<p>\u2714 non-invasive data acquisition in suitable conditions<br \/>\n\u2714 inspection without a shutdown where the safe procedure permits it<br \/>\n\u2714 efficient localisation of an acoustic source<br \/>\n\u2714 instrument-supported classification of discharge patterns<br \/>\n\u2714 documented measurement results<br \/>\n\u2714 earlier identification of conditions requiring further assessment<\/p>\n<h2><span class=\"ez-toc-section\" id=\"TERMOCENT_technical_diagnostics_for_electrical_installations\"><\/span>TERMOCENT: technical diagnostics for electrical installations<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>Acoustic-camera partial-discharge detection extends our non-invasive diagnostic capabilities for electrical installations in industry and buildings.<\/p>\n<p>Contact us if you need to:<\/p>\n<ul>\n<li>assess the condition of switchgear,<\/li>\n<li>inspect a transformer station,<\/li>\n<li>investigate a suspected partial-discharge source,<\/li>\n<li>obtain a report documenting the measurement and classification.<\/li>\n<\/ul>\n<p style=\"text-align: center;\"><strong>Call <a href=\"tel:+48530105398\">+48 530 105 398<\/a> or email <a title=\"Email TERMOCENT\" href=\"mailto:biuro@termocent.pl\">biuro@termocent.pl<\/a><\/strong><\/p>\n","protected":false},"excerpt":{"rendered":"<p>What are partial discharges? Partial discharges (PD) are localised electrical discharges that do not completely bridge the insulation between conductors. They can develop at weak points in insulation, around sharp edges of conductive components, in air voids, on contaminated surfaces or as materials age. One common type is corona discharge, which occurs in a strong [&hellip;]<\/p>\n","protected":false},"author":3,"featured_media":5057,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[23],"tags":[],"class_list":["post-5793","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-articles"],"acf":[],"permalink_manager":null,"_links":{"self":[{"href":"https:\/\/termocent.com\/en\/wp-json\/wp\/v2\/posts\/5793","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/termocent.com\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/termocent.com\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/termocent.com\/en\/wp-json\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/termocent.com\/en\/wp-json\/wp\/v2\/comments?post=5793"}],"version-history":[{"count":1,"href":"https:\/\/termocent.com\/en\/wp-json\/wp\/v2\/posts\/5793\/revisions"}],"predecessor-version":[{"id":5794,"href":"https:\/\/termocent.com\/en\/wp-json\/wp\/v2\/posts\/5793\/revisions\/5794"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/termocent.com\/en\/wp-json\/wp\/v2\/media\/5057"}],"wp:attachment":[{"href":"https:\/\/termocent.com\/en\/wp-json\/wp\/v2\/media?parent=5793"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/termocent.com\/en\/wp-json\/wp\/v2\/categories?post=5793"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/termocent.com\/en\/wp-json\/wp\/v2\/tags?post=5793"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}