{"id":14296,"date":"2019-01-10T11:00:36","date_gmt":"2019-01-10T19:00:36","guid":{"rendered":"http:\/\/www.palada.net\/index.php\/2019\/01\/10\/news-8048\/"},"modified":"2019-01-10T11:00:36","modified_gmt":"2019-01-10T19:00:36","slug":"news-8048","status":"publish","type":"post","link":"https:\/\/www.palada.net\/index.php\/2019\/01\/10\/news-8048\/","title":{"rendered":"VFDs and soft starters: is there really a competition?"},"content":{"rendered":"<p><strong>Credit to Author: Mohamed Gamal| Date: Thu, 10 Jan 2019 15:45:33 +0000<\/strong><\/p>\n<p>This post is part of our series on\u00a0<a href=\"http:\/\/schneider-electric.com\/motor-management\">motor management<\/a>\u00a0which covers various aspects of motor integration in an electrical network and the industrial process.<\/p>\n<p>End-users are frequently coming to us with the request to help them choose a better solution\u00a0between\u00a0variable frequency drive (VFD) or soft\u00a0starter (SS).<\/p>\n<p>For example: an intake pumping station in Egypt. The initial design was to use MV SS as a starting method for the intake pumps, keeping in mind that the intake pumps are a variable load, depending on the usage. In this case, the client was willing to change to VFD if we could prove the cost benefit on both the CAPEX and OPEX.<\/p>\n<p> <a href=\"https:\/\/blog.schneider-electric.com\/machine-and-process-management\/2015\/04\/22\/variable-speed-drive-back-features\/\"><img loading=\"lazy\" decoding=\"async\" class=\"aligncenter size-full wp-image-53891\" src=\"https:\/\/blog.schneider-electric.com\/wp-content\/uploads\/2019\/01\/Keycode-600x300-3.png\" alt=\"\" width=\"600\" height=\"300\" srcset=\"https:\/\/blog.schneider-electric.com\/wp-content\/uploads\/2019\/01\/Keycode-600x300-3.png 600w, https:\/\/blog.schneider-electric.com\/wp-content\/uploads\/2019\/01\/Keycode-600x300-3-300x150.png 300w\" sizes=\"auto, (max-width: 600px) 100vw, 600px\" \/><\/a> <\/p>\n<p>The\u00a0post will discuss the\u00a0benefits of using VFD over\u00a0SS\u00a0generally, and in the application of booster pumps specifically. It will\u00a0show the advantages of using the VFDs in energy saving, cost optimization\u00a0and\u00a0reduction\u00a0of local\u00a0generation capacity.<\/p>\n<p><b>What is a VFD?<\/b><\/p>\n<ul>\n<li>A Variable Frequency Drive (VFD) is a type of motor controller that drives an electric motor by varying the frequency and voltage supplied to it.<\/li>\n<\/ul>\n<ul>\n<li>Other names for a VFD\u00a0include:\u00a0variable speed drive, adjustable speed drive and adjustable frequency drive.<\/li>\n<\/ul>\n<p>The frequency of the power applied to an AC motor determines the motor speed, approximated to the slip, based on the following equation:<\/p>\n<h6 style=\"text-align: center\"><img loading=\"lazy\" decoding=\"async\" class=\"aligncenter wp-image-53902\" src=\"https:\/\/blog.schneider-electric.com\/wp-content\/uploads\/2019\/01\/Image-0.png\" alt=\"\" width=\"136\" height=\"31\" \/>Where: N= speed, f=frequency and p=no. of poles.<\/h6>\n<ul>\n<li>Want to learn more about VFD? Read\u00a0<a href=\"https:\/\/blog.schneider-electric.com\/machine-and-process-management\/2015\/04\/22\/variable-speed-drive-back-features\/\">Variable speed drive: Back to the features<\/a><\/li>\n<\/ul>\n<p><b>What is a\u00a0<\/b><b>s<\/b><b>oft<\/b><b>\u00a0<\/b><b>s<\/b><b>tarter?<\/b><\/p>\n<p>A soft-starter (SS) is a thyristor based electronic device, used with AC electrical motors to temporarily reduce the torque in the power train, and the electric current surge of the motor during start-up by controlling the conduction time of the thyristors. They provide a gentle ramp up to full speed and are used for both start-up and stopping. Soft-starters reduce the mechanical stress on the motor and shaft, as well as the electrodynamic stresses on the attached power cables and electrical distribution network.<\/p>\n<p> <img loading=\"lazy\" decoding=\"async\" class=\"aligncenter size-full wp-image-53881\" src=\"https:\/\/blog.schneider-electric.com\/wp-content\/uploads\/2019\/01\/Image-1-1.png\" alt=\"\" width=\"1102\" height=\"523\" srcset=\"https:\/\/blog.schneider-electric.com\/wp-content\/uploads\/2019\/01\/Image-1-1.png 1102w, https:\/\/blog.schneider-electric.com\/wp-content\/uploads\/2019\/01\/Image-1-1-300x142.png 300w, https:\/\/blog.schneider-electric.com\/wp-content\/uploads\/2019\/01\/Image-1-1-768x364.png 768w, https:\/\/blog.schneider-electric.com\/wp-content\/uploads\/2019\/01\/Image-1-1-1024x486.png 1024w\" sizes=\"auto, (max-width: 1102px) 100vw, 1102px\" \/> <\/p>\n<h3><b>Some benefits of using VFDs over soft<\/b><b>\u00a0<\/b><b>starters:<\/b><\/h3>\n<h4><b><\/b><b>1. Energy saving:<\/b><\/h4>\n<p>The affinity laws (also known as the &#8220;Fan Laws&#8221; or &#8220;Pump Laws&#8221;) for pumps are used in hydraulics to express the relationship between variables involved in pump or fan performance (such as head, volumetric flow rate, shaft speed) and power. They apply to pumps, fans, and hydraulic turbines. In these rotary implements, the affinity laws apply both to centrifugal and axial flows.<\/p>\n<p>For the relation between the pump power and speed:<\/p>\n<p> <img loading=\"lazy\" decoding=\"async\" class=\"aligncenter wp-image-53887\" src=\"https:\/\/blog.schneider-electric.com\/wp-content\/uploads\/2019\/01\/Picture3-c.png\" alt=\"\" width=\"182\" height=\"74\" \/> <\/p>\n<h6 style=\"text-align: center\"><span class=\"TextRun SCXW127457668\" lang=\"EN-US\" xml:lang=\"EN-US\"><span class=\"NormalTextRun SCXW127457668\">Where: P1 = needed power<\/span><\/span><span class=\"TextRun SCXW127457668\" lang=\"EN-US\" xml:lang=\"EN-US\"><span class=\"NormalTextRun SCXW127457668\">P2 =\u00a0<\/span><\/span><span class=\"TextRun SCXW127457668\" lang=\"EN-US\" xml:lang=\"EN-US\"><span class=\"NormalTextRun SCXW127457668\">f<\/span><\/span><span class=\"TextRun SCXW127457668\" lang=\"EN-US\" xml:lang=\"EN-US\"><span class=\"NormalTextRun SCXW127457668\">ull power<\/span><\/span><span class=\"TextRun SCXW127457668\" lang=\"EN-US\" xml:lang=\"EN-US\"><span class=\"NormalTextRun SCXW127457668\">\u00a0\u00a0\u00a0 N1 =\u00a0<\/span><\/span><span class=\"TextRun SCXW127457668\" lang=\"EN-US\" xml:lang=\"EN-US\"><span class=\"NormalTextRun SCXW127457668\">needed<\/span><\/span><span class=\"TextRun SCXW127457668\" lang=\"EN-US\" xml:lang=\"EN-US\"><span class=\"NormalTextRun SCXW127457668\">\u00a0speed<\/span><\/span><span class=\"TextRun SCXW127457668\" lang=\"EN-US\" xml:lang=\"EN-US\"><span class=\"NormalTextRun SCXW127457668\">\u00a0\u00a0\u00a0 N2 =\u00a0<\/span><\/span><span class=\"TextRun SCXW127457668\" lang=\"EN-US\" xml:lang=\"EN-US\"><span class=\"NormalTextRun SCXW127457668\">f<\/span><\/span><span class=\"TextRun SCXW127457668\" lang=\"EN-US\" xml:lang=\"EN-US\"><span class=\"NormalTextRun SCXW127457668\">ull speed.<\/span><\/span><\/h6>\n<p><span class=\"TextRun SCXW75367462\" lang=\"EN-US\" xml:lang=\"EN-US\"><span class=\"NormalTextRun SCXW75367462\">Having said that, if at any time during operation we need to run the pump at 80% of its speed, using a\u00a0<\/span><\/span><span class=\"TextRun SCXW75367462\" lang=\"EN-US\" xml:lang=\"EN-US\"><span class=\"NormalTextRun SCXW75367462\">VFD<\/span><\/span><span class=\"TextRun SCXW75367462\" lang=\"EN-US\" xml:lang=\"EN-US\"><span class=\"NormalTextRun SCXW75367462\">\u00a0we will be able to reduce the speed during operation, and this will lead to a significant decrease in absorbed power as follows:<\/span><\/span><\/p>\n<p> <img loading=\"lazy\" decoding=\"async\" class=\"aligncenter wp-image-53888\" src=\"https:\/\/blog.schneider-electric.com\/wp-content\/uploads\/2019\/01\/Picture3-d.png\" alt=\"\" width=\"207\" height=\"75\" srcset=\"https:\/\/blog.schneider-electric.com\/wp-content\/uploads\/2019\/01\/Picture3-d.png 397w, https:\/\/blog.schneider-electric.com\/wp-content\/uploads\/2019\/01\/Picture3-d-300x109.png 300w\" sizes=\"auto, (max-width: 207px) 100vw, 207px\" \/> <\/p>\n<h6 style=\"text-align: center\"><span class=\"TextRun Highlight SCXW241232255\" lang=\"EN-US\" xml:lang=\"EN-US\"><span class=\"NormalTextRun SCXW241232255\">\u2234<\/span><\/span><span class=\"TextRun SCXW241232255\" lang=\"EN-US\" xml:lang=\"EN-US\"><span class=\"NormalTextRun SCXW241232255\">\u00a0P(needed) = 0.512*P(full).<\/span><\/span><\/h6>\n<p><b>So, at\u00a0<\/b><b>80%\u00a0<\/b><b>speed, we can save up to\u00a0<\/b><b>50%\u00a0<\/b><b>of the motor power using the VFD, which will lead to increasing motor life time and decreasing the project OPEX.\u00a0<\/b><\/p>\n<p>For more on this you can head to this blog post:<b>\u00a0<\/b><a href=\"https:\/\/blog.schneider-electric.com\/energy-management-energy-efficiency\/2016\/08\/01\/energy-efficiency-induction-motor-applications-two-reasons-choose-variable-speed-drive-vsd\/\">About Energy Efficiency of Induction Motor Applications: Two Reasons to Choose a\u00a0Variable Speed Drive (VSD)\u202f<\/a><\/p>\n<h4><b>2. Generator capacity:<\/b><\/h4>\n<p>For sizing a generator, we should consider two factors:\u00a0loading and starting.<\/p>\n<ul>\n<li><b>Loading check:<\/b><\/li>\n<\/ul>\n<p>When using the soft\u00a0starter or VFD, total load will be considered, so we will need equal total generator power in both cases, regardless of the starting method.<\/p>\n<ul>\n<li><b>Starting check<\/b><b>:<\/b><\/li>\n<\/ul>\n<p><b>For\u00a0<\/b><b>s<\/b><b>oft<\/b><b>\u00a0<\/b><b>starters:<\/b><\/p>\n<p>Starting factor for soft\u00a0starters is\u00a0<b>3<\/b>, so we\u00a0will consider sizing on two steps as follows:<\/p>\n<p>Starting of biggest Load (kVA) = Biggest load\u00a0*\u00a0starting factor =\u00a0<b>3<\/b><b>\u00a0<\/b>*\u00a0Biggest load<\/p>\n<p>Total Load before starting of biggest load = Total load \u2013 biggest load.<\/p>\n<p><b>\u2234<\/b><b>Total Load with starting of biggest load = Total Load before starting of biggest load +\u00a0<\/b><b>3<\/b><b>\u00a0<\/b><b>*<\/b><b>\u00a0<\/b><b>Biggest load.<\/b><\/p>\n<p><b>For VFDs:<\/b><\/p>\n<p>Starting factor for soft starters is\u00a0<b>1<\/b>, so we will consider sizing as follows:<\/p>\n<p>Starting of biggest Load (kVA) = Biggest load\u00a0*\u00a0starting factor =\u00a01\u00a0*\u00a0Biggest load.<\/p>\n<p>Total Load before starting of biggest load = Total load \u2013 biggest load<\/p>\n<p><b>Total Load with starting of biggest load = Total Load before starting of biggest load +\u00a0<\/b><b>1<\/b><b>\u00a0\u00a0<\/b><b>*<\/b><b>\u00a0<\/b><b>Biggest load.<\/b><\/p>\n<p><b>Obviously using VFDs will lead to\u00a0<\/b><b>lower\u00a0<\/b><b>generator capacity requirement, due to the lower starting factor. Therefore smaller &amp; cheaper generators can be used, which will lead to CAPEX reduction.<\/b><\/p>\n<h3><b>Case study:<\/b><\/h3>\n<p>The intake pumping station, 4&#215;1580 kW (1859 kVA) pumps, was initially designed using soft starters. Therefore, generation station was sized to 12 MVA.<\/p>\n<p> <img loading=\"lazy\" decoding=\"async\" class=\"aligncenter wp-image-53895\" src=\"https:\/\/blog.schneider-electric.com\/wp-content\/uploads\/2019\/01\/Picture4-c.png\" alt=\"\" width=\"298\" height=\"253\" srcset=\"https:\/\/blog.schneider-electric.com\/wp-content\/uploads\/2019\/01\/Picture4-c.png 497w, https:\/\/blog.schneider-electric.com\/wp-content\/uploads\/2019\/01\/Picture4-c-300x255.png 300w\" sizes=\"auto, (max-width: 298px) 100vw, 298px\" \/> <\/p>\n<h6 style=\"text-align: center\"><span class=\"TextRun SCXW257489874\" lang=\"EN-US\" xml:lang=\"EN-US\"><span class=\"NormalTextRun SCXW257489874\">Figure<\/span><\/span><span class=\"TextRun SCXW257489874\" lang=\"EN-US\" xml:lang=\"EN-US\"><span class=\"NormalTextRun SCXW257489874\">\u00a0<\/span><\/span><span class=\"FieldRange SCXW257489874\"><span class=\"TextRun SCXW257489874\" lang=\"EN-US\" xml:lang=\"EN-US\"><span class=\"NormalTextRun SCXW257489874\">1<\/span><\/span><\/span><span class=\"TextRun SCXW257489874\" lang=\"EN-US\" xml:lang=\"EN-US\"><span class=\"NormalTextRun SCXW257489874\">\u00a0Initial design with soft\u00a0<\/span><\/span><span class=\"TextRun SCXW257489874\" lang=\"EN-US\" xml:lang=\"EN-US\"><span class=\"NormalTextRun SCXW257489874\">starters (SS)<\/span><\/span><\/h6>\n<p>To verify that VFDs can reduce the generation capacity, we performed the following study:<\/p>\n<ul>\n<li><b>Loading check:<\/b><\/li>\n<\/ul>\n<p>When using the soft starter or VFD, total load will be 7,435 kVA so we will need total generator power per standards:\u00a0<b>9,000 kVA<\/b>. (three\u00a0generators, each rated at 3 MVA), to keep loading at less than 80% for standby generators<\/p>\n<ul>\n<li><b>Starting check:<\/b><\/li>\n<\/ul>\n<p><b>1. For s<\/b><b>oft starters:<\/b><\/p>\n<p>Starting factor for soft starters is\u00a0<b>3<\/b>, so we will consider sizing as follows:<\/p>\n<p>Starting of biggest Load (kVA) = Biggest load*starting factor = 1859*3 = 5576.<\/p>\n<p>Total Load before starting of biggest load = Total load \u2013 biggest load = 7435 \u2013 1859 = 5576.<\/p>\n<p>Total Load with starting of biggest load = 5576 + 5576 = 11152.<\/p>\n<p><b>\u2234 Total needed generator power confirmed at\u00a0<\/b><b>12,000 kVA.<\/b><\/p>\n<p><b>2. For VFDs:<\/b><\/p>\n<p>Starting factor for VFD is\u00a0<b>1<\/b>, so we will consider sizing as follows:<\/p>\n<p>Starting of biggest Load (kVA) = Biggest load*starting factor = 1859*1 = 1859.<\/p>\n<p>Total Load before starting of biggest load = Total load \u2013 biggest load = 7435 \u2013 1859 = 5576.<\/p>\n<p>Total Load with starting of biggest load = 1859 + 5576 = 8365.<\/p>\n<p><b>\u2234 Total needed generator power can be reduced to\u00a0<\/b><b>9,000 kVA.<\/b><\/p>\n<p><b>As a standard, one 3000 kVA Generators will be saved.\u00a0<\/b><\/p>\n<p> <img loading=\"lazy\" decoding=\"async\" class=\"aligncenter wp-image-53896\" src=\"https:\/\/blog.schneider-electric.com\/wp-content\/uploads\/2019\/01\/Picture5-c.png\" alt=\"\" width=\"315\" height=\"279\" srcset=\"https:\/\/blog.schneider-electric.com\/wp-content\/uploads\/2019\/01\/Picture5-c.png 504w, https:\/\/blog.schneider-electric.com\/wp-content\/uploads\/2019\/01\/Picture5-c-300x265.png 300w\" sizes=\"auto, (max-width: 315px) 100vw, 315px\" \/> <\/p>\n<h6 style=\"text-align: center\"><span class=\"TextRun SCXW115454896\" lang=\"EN-US\" xml:lang=\"EN-US\"><span class=\"NormalTextRun SCXW115454896\">Figure\u00a0<\/span><\/span><span class=\"FieldRange SCXW115454896\"><span class=\"TextRun SCXW115454896\" lang=\"EN-US\" xml:lang=\"EN-US\"><span class=\"NormalTextRun SCXW115454896\">2<\/span><\/span><\/span><span class=\"TextRun SCXW115454896\" lang=\"EN-US\" xml:lang=\"EN-US\"><span class=\"NormalTextRun SCXW115454896\">\u00a0Optimized design, generation and variable speed drive<\/span><\/span><\/h6>\n<p>Despite the price increase due to using VFDs instead of soft starters, decreasing the generation capacity will still lead to a\u00a035%\u00a0decrease in the total project CAPEX.<\/p>\n<p>The post <a rel=\"nofollow\" href=\"https:\/\/blog.schneider-electric.com\/water\/2019\/01\/10\/vfds-and-soft-starters-is-there-really-a-competition\/\">VFDs and soft starters: is there really a competition?<\/a> appeared first on <a rel=\"nofollow\" href=\"https:\/\/blog.schneider-electric.com\">Schneider Electric Blog<\/a>.<\/p>\n<p><a href=\"https:\/\/blog.schneider-electric.com\/water\/2019\/01\/10\/vfds-and-soft-starters-is-there-really-a-competition\/\" target=\"bwo\" >http:\/\/blog.schneider-electric.com\/feed\/<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"<p><strong>Credit to Author: Mohamed Gamal| Date: Thu, 10 Jan 2019 15:45:33 +0000<\/strong><\/p>\n<p>This post is part of our series on\u00a0motor management\u00a0which covers various aspects of motor integration in an electrical network and the industrial process. End-users are frequently coming to us with&#8230;  <a href=\"https:\/\/blog.schneider-electric.com\/water\/2019\/01\/10\/vfds-and-soft-starters-is-there-really-a-competition\/\" title=\"ReadVFDs and soft starters: is there really a competition?\">Read more &#187;<\/a><\/p>\n<p>The post <a rel=\"nofollow\" href=\"https:\/\/blog.schneider-electric.com\/water\/2019\/01\/10\/vfds-and-soft-starters-is-there-really-a-competition\/\">VFDs and soft starters: is there really a competition?<\/a> appeared first on <a rel=\"nofollow\" href=\"https:\/\/blog.schneider-electric.com\">Schneider Electric Blog<\/a>.<\/p>\n","protected":false},"author":4,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"colormag_page_container_layout":"default_layout","colormag_page_sidebar_layout":"default_layout","footnotes":""},"categories":[12389,12388],"tags":[20643,20644,18924,18925,12438,15374,15375,16868,18027,18028,4229],"class_list":["post-14296","post","type-post","status-publish","format-standard","hentry","category-scadaics","category-schneider","tag-energy-saving","tag-generators","tag-inertia","tag-load-torque","tag-miningmetalsminerals","tag-motor-management","tag-motor-starting","tag-motors","tag-starting-methods","tag-starting-solutions","tag-water"],"_links":{"self":[{"href":"https:\/\/www.palada.net\/index.php\/wp-json\/wp\/v2\/posts\/14296","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.palada.net\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.palada.net\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.palada.net\/index.php\/wp-json\/wp\/v2\/users\/4"}],"replies":[{"embeddable":true,"href":"https:\/\/www.palada.net\/index.php\/wp-json\/wp\/v2\/comments?post=14296"}],"version-history":[{"count":0,"href":"https:\/\/www.palada.net\/index.php\/wp-json\/wp\/v2\/posts\/14296\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.palada.net\/index.php\/wp-json\/wp\/v2\/media?parent=14296"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.palada.net\/index.php\/wp-json\/wp\/v2\/categories?post=14296"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.palada.net\/index.php\/wp-json\/wp\/v2\/tags?post=14296"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}