{"id":559,"date":"2021-04-08T23:00:00","date_gmt":"2021-04-08T15:00:00","guid":{"rendered":"http:\/\/powerquality.sg\/wordpress\/?p=559"},"modified":"2021-04-08T23:56:07","modified_gmt":"2021-04-08T15:56:07","slug":"frequency-changes-during-a-voltage-dip","status":"publish","type":"post","link":"http:\/\/powerquality.sg\/wordpress\/?p=559","title":{"rendered":"Frequency Changes During A Voltage Dip"},"content":{"rendered":"\n<p>&#8220;Does frequency changes during a voltage dip?&#8221; &#8211; A favourite question among many. The answer is &#8220;Yes&#8221;.<\/p>\n\n\n\n<p>This will be quickly followed by &#8220;But why our power quality monitor did not show significant changes in the frequency values even though a voltage dip event was captured?&#8221; The general answer is that the standard (IEC 61000-4-30) does not require it to measure such detailed changes in frequency values.<\/p>\n\n\n\n<p>With the voltage waveforms captured, it is technically possible to calculate the frequency values during a particular event (say a voltage dip). Here&#8217;s an example, where the event waveforms were post-processed (via the Dranetz Dranview 7 software). <\/p>\n\n\n\n<figure class=\"wp-block-image size-large\"><a href=\"http:\/\/powerquality.sg\/wordpress\/wp-content\/uploads\/2021\/04\/freqchangedip.png\"><img decoding=\"async\" loading=\"lazy\" width=\"1024\" height=\"790\" src=\"http:\/\/powerquality.sg\/wordpress\/wp-content\/uploads\/2021\/04\/freqchangedip-1024x790.png\" alt=\"\" class=\"wp-image-561\" srcset=\"http:\/\/powerquality.sg\/wordpress\/wp-content\/uploads\/2021\/04\/freqchangedip-1024x790.png 1024w, http:\/\/powerquality.sg\/wordpress\/wp-content\/uploads\/2021\/04\/freqchangedip-300x231.png 300w, http:\/\/powerquality.sg\/wordpress\/wp-content\/uploads\/2021\/04\/freqchangedip-768x592.png 768w, http:\/\/powerquality.sg\/wordpress\/wp-content\/uploads\/2021\/04\/freqchangedip-1536x1185.png 1536w, http:\/\/powerquality.sg\/wordpress\/wp-content\/uploads\/2021\/04\/freqchangedip.png 1539w\" sizes=\"(max-width: 1024px) 100vw, 1024px\" \/><\/a><\/figure>\n\n\n\n<p>Such post-processing feature is very useful especially in generator load-test applications, where one will be interested to know both the voltage and frequency changes during every step-load change. An example is shown below. One just need to ensure that the pre\/during\/post event waveforms were set to be captured properly (i.e enough cycles). The software will do the rest.<\/p>\n\n\n\n<figure class=\"wp-block-image size-large\"><a href=\"http:\/\/powerquality.sg\/wordpress\/wp-content\/uploads\/2021\/04\/gen-step-load.png\"><img decoding=\"async\" loading=\"lazy\" width=\"1024\" height=\"703\" src=\"http:\/\/powerquality.sg\/wordpress\/wp-content\/uploads\/2021\/04\/gen-step-load-1024x703.png\" alt=\"\" class=\"wp-image-562\" srcset=\"http:\/\/powerquality.sg\/wordpress\/wp-content\/uploads\/2021\/04\/gen-step-load-1024x703.png 1024w, http:\/\/powerquality.sg\/wordpress\/wp-content\/uploads\/2021\/04\/gen-step-load-300x206.png 300w, http:\/\/powerquality.sg\/wordpress\/wp-content\/uploads\/2021\/04\/gen-step-load-768x527.png 768w, http:\/\/powerquality.sg\/wordpress\/wp-content\/uploads\/2021\/04\/gen-step-load-1536x1054.png 1536w, http:\/\/powerquality.sg\/wordpress\/wp-content\/uploads\/2021\/04\/gen-step-load.png 1730w\" sizes=\"(max-width: 1024px) 100vw, 1024px\" \/><\/a><\/figure>\n","protected":false},"excerpt":{"rendered":"<p>&#8220;Does frequency changes during a voltage dip?&#8221; &#8211; A favourite question among many. The answer is &#8220;Yes&#8221;. This will be quickly followed by &#8220;But why our power quality monitor did not show significant changes in the frequency values even though a voltage dip event was captured?&#8221; The general answer is that the standard (IEC 61000-4-30) [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":204,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"jetpack_post_was_ever_published":false,"_jetpack_newsletter_access":"","_jetpack_newsletter_tier_id":0,"jetpack_publicize_message":"","jetpack_is_tweetstorm":false,"jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":true,"jetpack_social_options":{"image_generator_settings":{"template":"highway","enabled":false}}},"categories":[13,10],"tags":[],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"http:\/\/powerquality.sg\/wordpress\/wp-content\/uploads\/2014\/03\/fig1-definition.png","jetpack_shortlink":"https:\/\/wp.me\/p41TEZ-91","jetpack_sharing_enabled":true,"_links":{"self":[{"href":"http:\/\/powerquality.sg\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/559"}],"collection":[{"href":"http:\/\/powerquality.sg\/wordpress\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/powerquality.sg\/wordpress\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/powerquality.sg\/wordpress\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/powerquality.sg\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=559"}],"version-history":[{"count":4,"href":"http:\/\/powerquality.sg\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/559\/revisions"}],"predecessor-version":[{"id":565,"href":"http:\/\/powerquality.sg\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/559\/revisions\/565"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/powerquality.sg\/wordpress\/index.php?rest_route=\/wp\/v2\/media\/204"}],"wp:attachment":[{"href":"http:\/\/powerquality.sg\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=559"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/powerquality.sg\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=559"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/powerquality.sg\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=559"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}