{"id":5850,"date":"2020-10-21T10:54:16","date_gmt":"2020-10-21T10:54:16","guid":{"rendered":"https:\/\/powerside.com\/?p=5850"},"modified":"2023-02-21T21:44:58","modified_gmt":"2023-02-21T21:44:58","slug":"the-itic-graph-and-curve-a-valuable-tool-for-voltage-disturbance-analysis","status":"publish","type":"post","link":"https:\/\/modomodostage.com\/_client\/PWS\/PWS101\/the-itic-graph-and-curve-a-valuable-tool-for-voltage-disturbance-analysis\/","title":{"rendered":"The ITIC Graph and Curve a Valuable Tool for Voltage Disturbance Analysis"},"content":{"rendered":"\n<p class=\"wp-block-paragraph\">Whether in Data Centers or heavy industry, whether delivered by the grid or locally induced, power sags (a.k.a. intermittent voltage reductions) and swells (a.k.a. intermittent voltage increases) are a constant threat to business productivity and equipment reliability. In the best case, equipment may ride through minor reductions of short duration. In contrast, larger, longer reductions can result in random process variations, malfunctions, equipment tripping off, and extended recovery or repair times. Likewise, voltage excess can result in equipment over-speed, excess heating, or protective tripping.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Dating back to the 1970s, the Computer and\nBusiness Equipment Manufacturers Association (CBEMA) sought to codify voltage\ndeviations and provided a simplified standard approach to categorizing them and\nhow to think about them. What began life as the CBEMA Power Acceptability\nCurve, which defines the operating envelope for IT equipment based on voltage\ndeviation and duration, has been supplanted in 2000 by the Information\nTechnology and Industry Council (ITIC) Curve, with similar properties. <\/p>\n\n\n\n<p class=\"wp-block-paragraph\">So, let\u2019s go through the graph, below, in\ndetail. <\/p>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"695\" data-src=\"https:\/\/modomodostage.com\/_client\/PWS\/PWS101\/wp-content\/uploads\/2020\/10\/ITIC-1024x695.jpg\" alt=\"\" class=\"wp-image-5852 lazyload\" data-srcset=\"https:\/\/modomodostage.com\/_client\/PWS\/PWS101\/wp-content\/uploads\/2020\/10\/ITIC-1024x695.jpg 1024w, https:\/\/modomodostage.com\/_client\/PWS\/PWS101\/wp-content\/uploads\/2020\/10\/ITIC-300x203.jpg 300w, https:\/\/modomodostage.com\/_client\/PWS\/PWS101\/wp-content\/uploads\/2020\/10\/ITIC.jpg 1784w\" data-sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" src=\"data:image\/gif;base64,R0lGODlhAQABAAAAACH5BAEKAAEALAAAAAABAAEAAAICTAEAOw==\" style=\"--smush-placeholder-width: 1024px; --smush-placeholder-aspect-ratio: 1024\/695;\" \/><noscript><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"695\" src=\"https:\/\/modomodostage.com\/_client\/PWS\/PWS101\/wp-content\/uploads\/2020\/10\/ITIC-1024x695.jpg\" alt=\"\" class=\"wp-image-5852\" srcset=\"https:\/\/modomodostage.com\/_client\/PWS\/PWS101\/wp-content\/uploads\/2020\/10\/ITIC-1024x695.jpg 1024w, https:\/\/modomodostage.com\/_client\/PWS\/PWS101\/wp-content\/uploads\/2020\/10\/ITIC-300x203.jpg 300w, https:\/\/modomodostage.com\/_client\/PWS\/PWS101\/wp-content\/uploads\/2020\/10\/ITIC.jpg 1784w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><\/noscript><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\">CBEMA defined its envelope using continuous\ncurves, whereas the ITIC Curve is paradoxically defined in piecewise linear\nsegments, making it computationally simpler to operationalize and little\ndifferent in value. The curves represent a standardized model of the supply\nvoltage operational envelope under which IT equipment is expected to \u201cperform,\u201d\nmore on which later. The vertical axis represents the percentage above or below\nnominal voltage during an event, the duration of which is plotted on the\nhorizontal axis. The normal operational envelope is on the left side of the\nlimit lines; the right side, whether upward or downward, are the zones under\nwhich abnormal operation may be expected. <\/p>\n\n\n\n<p class=\"wp-block-paragraph\">As can be seen, the sag and swell curves\nare essentially asymptotic to within +\/- 10% of nominal; IT equipment is\nexpected to operate continuously and indefinitely (within the equipment\u2019s\nintrinsic limitations) subject to minor voltage variations of any duration. For\nevents between 0.5 s and 10 s duration, equipment should normally perform,\nprovided supply voltage is within +10 % \/- 20% of nominal. Continuous operation\nwith larger sags and swells is expected as the event time duration decreases.\nAdvanced processing can determine the source of disturbances, whether utility\nor in-facility, further adding to sag and swell data&#8217;s diagnostic value. <\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Before we go further, it is essential to\nrecognize what the ITIC curve is and what it isn\u2019t. The ITIC curve is a simple,\nuseful, and widely understood way of visualizing and classifying sags and\nswells and seeing the cumulative range and number of events that an individual\npiece of equipment or facility is subject to; Powerside\u2019s PQube Report Writer\nsoftware accomplishes precisely that. The ITIC curve is often specified for IT\nequipment, as one would expect. One thing to remember is that, while a wide range\nof equipment has similar properties to IT equipment, being built of similar\ncomponents, the design considerations for the equipment and the application,\nand the operating envelope, may be entirely different. So, no single ITIC-like\ncurve is universally applicable, and indeed, there are many like standards for\ndifferent industries, equipment, and geos. While the ITIC\/CBEMA philosophy and\ngraph are useful in many cases, there is no one-size-fits-all approach to\nequipment or system design, and ITIC-like curves are not design standards\nunless comprehensively specified.&nbsp; <\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Where this matters the most is in the\ntypical labeling of the ITIC IT curve, which often shows a \u201cno damage\u201d region\nfor extended sags below the limit and \u201cprohibited region\u201d for extended swells\nabove the limit, which may result in equipment damage. The simple truth is that\nthe desired behavior of Utilities, power sources, and equipment under stress is\ngenerally application- or location-specific. So the labeling of zones in a\nperformance envelope is often much more nuanced than this. <\/p>\n\n\n\n<p class=\"wp-block-paragraph\">A few examples serve to illustrate the\npoint. In some industries, it may be acceptable for equipment to recover from\nextended sags below the limits gracefully\u2026 liquid pumping or material\nprocessing, for example, where only quantity and not quality is lost from an\nevent. Contrariwise, in semiconductor manufacturing, or plastic molding,\nextended sags or swells may result in process nonuniformity or process-window\ndeviations, where the best-case outcome may be that the equipment gracefully\nenters a standby mode, or in worst case makes a full restart and ejects scrap\nmaterial. There is also the case of potential equipment stalling in machine processing\nor of vacuum or cooling loss, where a protective shutdown may be required to\navoid overheating or a costly restart. <\/p>\n\n\n\n<p class=\"wp-block-paragraph\">In the case of extended swells, high-value\nequipment such as Variable Speed Drives may have an overvoltage trip to prevent\ndamage when operated with supply voltage over 110% of nominal, even within ITIC\nlimits. On the other hand, even surprisingly expensive consumer electronics may\ninstead be designed with a sacrificial weak-link component, which by design\nfails safely in a sustained overvoltage, leaving the equipment irreparably\ndamaged. To repeat, there is no single equipment performance specification\nbased on an \u201cITIC-like curve\u201d unless the curve and the required behavior is\nfully defined.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">So, three cheers for the ITIC chart and\ncurve! Correctly interpreted, it&#8217;s a powerful way of visualizing the range and\nquantity of voltage disturbances that a plant or equipment is subject to and\nassessing each event&#8217;s severity. It can lead to pivotal decisions about the\nneed for and type of corrective action required. The IT-centric ITIC curve is a\nhelpful preliminary guideline but not a standard when assessing the performance\nof both Utilities and plants in a wide range of applications. <\/p>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"359\" data-src=\"https:\/\/modomodostage.com\/_client\/PWS\/PWS101\/wp-content\/uploads\/2020\/10\/powerside-education-1-1024x359.jpg\" alt=\"powerside topical\" class=\"wp-image-5860 lazyload\" data-srcset=\"https:\/\/modomodostage.com\/_client\/PWS\/PWS101\/wp-content\/uploads\/2020\/10\/powerside-education-1-1024x359.jpg 1024w, https:\/\/modomodostage.com\/_client\/PWS\/PWS101\/wp-content\/uploads\/2020\/10\/powerside-education-1-300x105.jpg 300w, https:\/\/modomodostage.com\/_client\/PWS\/PWS101\/wp-content\/uploads\/2020\/10\/powerside-education-1.jpg 1960w\" data-sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" src=\"data:image\/gif;base64,R0lGODlhAQABAAAAACH5BAEKAAEALAAAAAABAAEAAAICTAEAOw==\" style=\"--smush-placeholder-width: 1024px; --smush-placeholder-aspect-ratio: 1024\/359;\" \/><noscript><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"359\" src=\"https:\/\/modomodostage.com\/_client\/PWS\/PWS101\/wp-content\/uploads\/2020\/10\/powerside-education-1-1024x359.jpg\" alt=\"powerside topical\" class=\"wp-image-5860\" srcset=\"https:\/\/modomodostage.com\/_client\/PWS\/PWS101\/wp-content\/uploads\/2020\/10\/powerside-education-1-1024x359.jpg 1024w, https:\/\/modomodostage.com\/_client\/PWS\/PWS101\/wp-content\/uploads\/2020\/10\/powerside-education-1-300x105.jpg 300w, https:\/\/modomodostage.com\/_client\/PWS\/PWS101\/wp-content\/uploads\/2020\/10\/powerside-education-1.jpg 1960w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><\/noscript><\/figure>\n","protected":false},"excerpt":{"rendered":"<p>Whether in Data Centers or heavy industry, whether delivered by the grid or locally induced, power sags (a.k.a. intermittent voltage reductions) and swells (a.k.a. intermittent voltage increases) are a constant threat to business productivity and equipment reliability. In the best case, equipment may ride through minor reductions of short duration. In contrast, larger, longer reductions <a href=\"https:\/\/modomodostage.com\/_client\/PWS\/PWS101\/the-itic-graph-and-curve-a-valuable-tool-for-voltage-disturbance-analysis\/\" class=\"more-link\">&#8230;<span class=\"screen-reader-text\">  The ITIC Graph and Curve a Valuable Tool for Voltage Disturbance Analysis<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":15590,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[119],"tags":[],"class_list":["post-5850","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-power-quality-analysis-improvement"],"acf":[],"_links":{"self":[{"href":"https:\/\/modomodostage.com\/_client\/PWS\/PWS101\/wp-json\/wp\/v2\/posts\/5850","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/modomodostage.com\/_client\/PWS\/PWS101\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/modomodostage.com\/_client\/PWS\/PWS101\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/modomodostage.com\/_client\/PWS\/PWS101\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/modomodostage.com\/_client\/PWS\/PWS101\/wp-json\/wp\/v2\/comments?post=5850"}],"version-history":[{"count":2,"href":"https:\/\/modomodostage.com\/_client\/PWS\/PWS101\/wp-json\/wp\/v2\/posts\/5850\/revisions"}],"predecessor-version":[{"id":15599,"href":"https:\/\/modomodostage.com\/_client\/PWS\/PWS101\/wp-json\/wp\/v2\/posts\/5850\/revisions\/15599"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/modomodostage.com\/_client\/PWS\/PWS101\/wp-json\/wp\/v2\/media\/15590"}],"wp:attachment":[{"href":"https:\/\/modomodostage.com\/_client\/PWS\/PWS101\/wp-json\/wp\/v2\/media?parent=5850"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/modomodostage.com\/_client\/PWS\/PWS101\/wp-json\/wp\/v2\/categories?post=5850"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/modomodostage.com\/_client\/PWS\/PWS101\/wp-json\/wp\/v2\/tags?post=5850"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}