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[ { "title": "LEARN | 5 Ways to Improve Power Availability", "nid": "560", "body": "\u003Cp\u003E\u003Ca href=\u0022https://www.magnetgroup.co.za/news-letter.html\u0022\u003E\u003Cimg alt=\u0022power\u0022 data-entity-type=\u0022file\u0022 data-entity-uuid=\u0022c436f5b7-64f0-4b44-a5c6-48d443a3a4eb\u0022 height=\u0022286\u0022 src=\u0022/cms/drupal8-magnetgroup/sites/default/files/inline-images/Yokkaichi-Factory-Night-View_1200x675.jpg\u0022 width=\u0022509\u0022 class=\u0022align-center\u0022 /\u003E\u003C/a\u003E\u003C/p\u003E\n\u003Cp\u003EThe \u003Ca href=\u0022https://www.magnetgroup.co.za/solutions-electrical/index.php\u0022\u003E\u003Cstrong\u003Epower availability and reliability\u003C/strong\u003E\u003C/a\u003E of a distribution system encompasses its entire lifecycle, from design to operations. Schneider Electric challenges you to consider these five approaches:\u003C/p\u003E\n\u003Cp\u003E\u003Cstrong\u003E1. Pre-engineered reference designs\u003C/strong\u003E\u003C/p\u003E\n\u003Cp class=\u0022text-align-justify\u0022\u003EA pre-engineered medium and/or low voltage electrical distribution system will be based on a reference design that has been validated for the specific application.\u003C/p\u003E\n\u003Cp class=\u0022text-align-justify\u0022\u003EA design should include the core\u00A0\u003Ca href=\u0022https://www.se.com/ww/en/work/products/product-launch/ecostruxure-power-design-ecodial/\u0022\u003Epower system design\u003C/a\u003E, as well as the connected, digital layer of intelligence used for power management. To further enhance resilience the design can include backup power and power conditioning (e.g. generators, uninterruptible power supplies (UPS), automatic transfer switches (ATS), harmonic filtering). It should also comply with local regulations and international standards, and be optimized for safety to help avoid injury to people and damage to equipment.\u003C/p\u003E\n\u003Cp class=\u0022text-align-justify\u0022\u003EA pre-engineered reference design will also significantly streamline the design-build process, reducing both the overall risk and cost of implementing and operating the system. Specialized electrical distribution design software optimizes every aspect of the system for its specified application, taking into account all expected operational and environmental conditions, today and tomorrow. This will help future-proof the facility.\u003C/p\u003E\n\u003Cp\u003E\u003Cstrong\u003E2. Smart circuit breakers\u003C/strong\u003E\u003C/p\u003E\n\u003Cp class=\u0022text-align-justify\u0022\u003EThe newest circuit breaker technology protects people and equipment, while at the same time maintaining the operations of a facility. If a fault occurs at any point in an electrical distribution circuit, you don\u2019t want that fault to affect the power availability for the entire facility. Selective coordination is used by circuit breakers to rapidly isolate the problem section, tripping only the circuit breaker directly upstream of the problem section, without depriving the rest of the network of power.\u003C/p\u003E\n\u003Cp\u003E\u003Cimg alt=\u0022Selectivity\u0022 data-entity-type=\u0022file\u0022 data-entity-uuid=\u002252559599-c3cf-466f-b60f-6c55fb634407\u0022 height=\u0022226\u0022 src=\u0022/cms/drupal8-magnetgroup/sites/default/files/inline-images/Blog-Power-reliability-V4-1024x343.jpg\u0022 width=\u0022675\u0022 class=\u0022align-center\u0022 /\u003E\u003C/p\u003E\n\u003Cp class=\u0022text-align-justify\u0022\u003EElectrical distribution design enables you to optimize your installation design, selecting sizes and combinations of circuit breakers to provide \u2018total\u2019 selective coordination between all stages of the electrical distribution network.\u003C/p\u003E\n\u003Cp class=\u0022text-align-justify\u0022\u003EThe best circuit breakers are easy to maintain, withdrawable and plug-in features makes them easier to manage.\u00A0\u003Ca href=\u0022https://www.se.com/ww/en/product-category/4200-circuit-breakers-and-switches/?filter=business-4-low-voltage-products-and-systems\u0022\u003ESmart circuit breakers\u003C/a\u003E\u00A0also offer embedded metering capabilities to support\u00A0\u003Ca href=\u0022https://www.se.com/ww/en/work/campaign/innovation/power-distribution.jsp\u0022\u003Econnected power\u003C/a\u003E\u00A0management and predictive maintenance.\u003C/p\u003E\n\u003Cp\u003E\u003Cstrong\u003E3. Power management system\u003C/strong\u003E\u003C/p\u003E\n\u003Cp\u003EThroughout your power distribution system, there can be risks to reliability that are hidden and go unnoticed. A fully digitized electrical system can better withstand power disturbances and is resilient to downtime. A\u00A0\u003Ca href=\u0022https://www.se.com/uk/en/product-range-presentation/65404-ecostruxure-power-monitoring-expert-9.0/?parent-subcategory-id=80288\u0026amp;filter=business-4-low-voltage-products-and-systems\u0022\u003Epower management system\u003C/a\u003E\u00A0takes advantage of data from connected devices, acting like a microscope on your electrical system, continuously monitoring its performance and the assets connected to it. If any unexpected condition is detected, an alarm notifies personnel wherever they are so that they can immediately locate the issue and take action to prevent a critical situation.\u003C/p\u003E\n\u003Cp\u003EA\u00A0\u003Ca href=\u0022https://www.se.com/ww/en/work/campaign/innovation/power-distribution.jsp\u0022\u003Econnected powe\u003C/a\u003Er network includes intelligent, connected\u00A0\u003Ca href=\u0022https://www.se.com/us/en/product-range/64241-powerlogic-ion9000-series/?parent-subcategory-id=52520\u0026amp;filter=business-4-low-voltage-products-and-systems\u0022\u003Eadvanced power meters\u003C/a\u003E\u00A0that quickly reveal power quality issues \u2013 such as high harmonics or voltage sags \u2013 or other types of faults, while diagnostic tools help facility team determine root causes before they can cause an outage.\u003C/p\u003E\n\u003Cp\u003EA digitally-connected power management solution should also include wireless thermal sensors, for early detection of abnormal temperature rises on conductors and connection points. This will help reduce the risk of a fire or failure (and associated downtime), while avoiding the time and cost of annual infrared (IR) testing. Another recent innovation is the ability to monitor circuit breaker health and aging, with advanced analytics that enable more proactive maintenance, preventing performance issues, and extending breaker life. These capabilities help ensure that a clean, stable power is always available 24/7, while reducing operational costs.\u003C/p\u003E\n\u003Cp\u003E\u003Cstrong\u003E4. Expert services for predictive maintenance\u003C/strong\u003E\u003C/p\u003E\n\u003Cp\u003ECloud-based power management applications act as a portal to\u00A0\u003Ca href=\u0022https://www.se.com/us/en/work/services/field-services/power-management/\u0022\u003Eremote expert services\u003C/a\u003E. If your organization has limited onsite technical resources or expertise, these \u2018digital services\u2019 can help you reduce the complexity and time needed to manage your power distribution systems, while improving power quality, reliability, and availability.\u003C/p\u003E\n\u003Cp\u003EExpert advisors will monitor your operation 24/7, delivering condition-based insights about your electrical system health and asset performance. These insights enable a more predictive maintenance approach, resulting in fewer operational failures and a downtime reduction of 30 to 50%. Advisory services, including Schneider Electric\u00A0\u003Ca href=\u0022https://www.se.com/ww/en/locate/4-global-ecoxpert-locator\u0022\u003EEcoXpert partners\u003C/a\u003E, can also help you evolve your system over its life cycle.\u003C/p\u003E\n\u003Cp\u003E\u003Cstrong\u003E5. Fault localization and power recovery\u003C/strong\u003E\u003C/p\u003E\n\u003Cp\u003EDespite taking all these steps to prevent downtime, there is always the chance of unplanned downtime. If a fault occurs, you need to minimize its duration and impact. Having the right products and software will help ensure a rapid recovery. Some of the newest tools will the on-site facility team automatically correlate system-wide data and reveal the propagation of a disturbance to isolate the source. In addition, smart protection relays, trip units, and accessories (e.g. auxiliary contacts, etc.) will help more quickly localize a fault, identifying the tripped circuit-breaker and its associated circuit. A smartphone app can then be used find the root cause of the incident, and have access to step-by-step guidance to help quickly restore power.\u003C/p\u003E\n\u003Cp\u003EIn the more complex, more power-sensitive \u2018New Electric World\u2019, businesses face the risk of more unplanned downtime, highly inefficient electrical operations, and more frequent equipment failures. These can all lead to higher OPEX spending and, in some cases, major financial losses. For these reasons, more focus must now be placed on using the right technologies and services to help ensure\u00A0\u003Ca href=\u0022https://www.se.com/ww/en/work/campaign/innovation/power-distribution.jsp\u0022\u003Einnovative power solutions\u003C/a\u003E.\u003C/p\u003E\n\u003Cp\u003E\u003Cstrong\u003EResources:\u003C/strong\u003E\u003C/p\u003E\n\u003Cp\u003E1. \u003Ca href=\u0022https://www.youtube.com/watch?v=UmyaillsNt4\u0026amp;list=PL0AHvVniUcgwcgSxZ8bJbYGbHrqklEBLp\u0026amp;index=23\u0022\u003E\u003Cstrong\u003EWATCH\u003C/strong\u003E\u003C/a\u003E a video on how to improve power availability\u003C/p\u003E\n\u003Cp\u003E2. \u003Ca href=\u0022https://download.schneider-electric.com/files?p_Doc_Ref=998-21359052_GMA\u0022\u003E\u003Cstrong\u003EDOWNLOAD\u003C/strong\u003E\u003C/a\u003E a guide on power availability and reliability solutions\u003C/p\u003E\n\u003Cp\u003E3. \u003Ca href=\u0022mailto:hello@magnetgroup.co.za?subject=Schneider Enquiry\u0022\u003E\u003Cstrong\u003ECHAT\u003C/strong\u003E\u003C/a\u003E to us about a Schneider solution for your facility\u003C/p\u003E\n\u003Cp\u003E\u00A0\u003C/p\u003E\n\u003Cp\u003E\u00A0\u003C/p\u003E\n\u003Cp\u003ESource:\u00A0\u003C/p\u003E\n\u003Cp\u003Ehttps://blog.se.com/power-management-metering-monitoring-power-quality/2020/11/06/5-ways-to-improve-power-availability-and-reliability-in-your-facility/?mkt_tok=MTc4LUdZRC02NjgAAAF_6UrA2EtHOC2Dn4lHUqMIkODAg0Wzu3iX-buW0jpn380QO6atltK181URa907KZm_gaVcnhmN0wk1PFzD1Nksn4nUPteogvXnCMVfMNLIT8Y3_fb_8kA\u003C/p\u003E\n\u003Cp\u003E\u00A0\u003C/p\u003E\n", "created": "Oct 2021", "terms": "Electrical, Education, Schneider" }, { "title": "LEARN | Cascading of Circuit Breakers pt 1", "nid": "552", "body": "\u003Cp class=\u0022text-align-justify\u0022\u003EAre you planning on renewing or adding \u003Ca href=\u0022https://www.magnetgroup.co.za/solutions-electrical/index.php\u0022\u003E\u003Cstrong\u003Ecircuit breakers\u003C/strong\u003E\u003C/a\u003E to your current electrical installation? Is it possible to reduce the cost of purchasing these circuit breakers whilst still being adequately protected?\u003C/p\u003E\n\u003Cp class=\u0022text-align-justify\u0022\u003EThis NEW series introduces you to the technique of how circuit breakers are cascaded in a system.\u003C/p\u003E\n\u003Cp class=\u0022text-align-justify\u0022\u003EIn Part 1 we give an explanation of what cascading is, its advantages, and the conditions required to implement cascading. In \u003Ca href=\u0022https://www.magnet.co.za/news.html?type=articles\u0026amp;name=LEARN--Cascading-of-Circuit-Breakers-pt-2\u0022\u003E\u003Cstrong\u003EPart 2\u003C/strong\u003E\u003C/a\u003E, we touch\u00A0on the topic of selectivity, by giving an overview on how it can be enhanced in your system by the implementation of cascading circuit breakers.\u003C/p\u003E\n\u003Cp class=\u0022text-align-justify\u0022\u003E\u00A0\u003C/p\u003E\n\u003Cp\u003E\u003Ca href=\u0022https://www.magnetgroup.co.za/solutions-electrical/news.php?type=articles\u0026amp;name=PRODUCT-NEWS--Schneider039s-Compact-NSXm-MCCB\u0022\u003E\u003Cimg alt=\u0022Schneider NSX\u0022 data-entity-type=\u0022file\u0022 data-entity-uuid=\u00224b0f15ae-eb25-419f-afe3-3ef9b78a7b99\u0022 height=\u0022249\u0022 src=\u0022/cms/drupal8-magnetgroup/sites/default/files/inline-images/35d07cecbfa8ef82d3db4c1d852a65c7.jpg\u0022 width=\u0022330\u0022 class=\u0022align-center\u0022 /\u003E\u003C/a\u003E\u003C/p\u003E\n\u003Cp class=\u0022text-align-justify\u0022\u003E\u003Cstrong\u003EWhat is Cascading of Circuit Breakers?\u003C/strong\u003E\u003C/p\u003E\n\u003Cp class=\u0022text-align-justify\u0022\u003EThe cascading of circuit breakers is a \u201Cback-up\u201D protection system which is implemented to allow for the installation of circuit breakers that are not able to handle the full capacity of the prospective short-circuit current of a fault at the point of installation.\u003C/p\u003E\n\u003Cp class=\u0022text-align-justify\u0022\u003EA requirement in cascading a system is to make sure that these circuit breakers are backed up a downstream/upstream fully rated circuit-breaker in a predetermined and tested coordination.\u00A0 It is vital to identify the fault level of a circuit breaker at a given point to allow for the installation of lower-rated circuit breakers downstream. This will ultimately allow for a reduction in costs.\u003C/p\u003E\n\u003Cp class=\u0022text-align-justify\u0022\u003E\u003Cstrong\u003EWhat does Cascading of Circuit Breakers mean? \u003C/strong\u003E\u003C/p\u003E\n\u003Cp class=\u0022text-align-justify\u0022\u003EThis is the term used when you have a panel with a high fault level (20kA) for example. The installation will consist of two circuit breakers in series. The main breaker located at the panel will be rated at fault level, whilst the breakers below can be of the lowest kA rating offered. You can save money without decreasing the safety level. The only problem with this system is when a fault occurs, then the upstream breaker, or both breakers, open to clear the fault.\u003C/p\u003E\n\u003Cp class=\u0022text-align-justify\u0022\u003E\u003Cstrong\u003EWhat are the Advantages of Cascading Circuit Breakers?\u003C/strong\u003E\u003C/p\u003E\n\u003Cp class=\u0022text-align-justify\u0022\u003EWhen \u003Cstrong\u003E\u003Ca href=\u0022https://go.schneider-electric.com/lp/178-GYD-668/ZA_202110_Schneider-Learning-Series-Webinar-Current-Limitation_MI-EF-LP.html\u0022\u003Ecurrent limitation\u003C/a\u003E\u003C/strong\u003E is implemented, it will benefit all downstream circuits that are controlled by the current-limiting circuit breaker concerned which, in most cases, is the main supply circuit breaker.\u003C/p\u003E\n\u003Cp class=\u0022text-align-justify\u0022\u003EThis principle is not restrictive, which means that current limiting circuit breakers can be installed at any point of the system where the downstream circuits could possibly be inadequately rated.\u003C/p\u003E\n\u003Cp class=\u0022text-align-justify\u0022\u003E\u003Cstrong\u003EThis results in:\u003C/strong\u003E\u003C/p\u003E\n\u003Col\u003E\n\u003Cli class=\u0022text-align-justify\u0022\u003ESimplified short-circuit calculations.\u003C/li\u003E\n\u003Cli class=\u0022text-align-justify\u0022\u003ESimplification which will result in a wider choice of downstream switchgear and appliances.\u003C/li\u003E\n\u003Cli class=\u0022text-align-justify\u0022\u003EThe use of cascading circuit breakers will allow for the installation of lighter-duty switchgear and appliances which will ultimately reduce the cost.\u003C/li\u003E\n\u003Cli class=\u0022text-align-justify\u0022\u003ELight-duty equipment that is installed will need less space as opposed to heavy-duty equipment.\u003C/li\u003E\n\u003C/ol\u003E\n\u003Cp class=\u0022text-align-justify\u0022\u003E\u003Cstrong\u003EWhat are the Conditions Required for the Implementation of Cascading Circuit Breakers? \u003C/strong\u003E\u003C/p\u003E\n\u003Cp class=\u0022text-align-justify\u0022\u003EThe implementation of the cascading technique should be allowed, provided that the amount of energy allowed through by the limiting circuit breaker is less than the withstand energy of all downstream circuit breakers.\u003C/p\u003E\n\u003Cp class=\u0022text-align-justify\u0022\u003E\u003Cstrong\u003EHow do you implement a cascading system?\u003C/strong\u003E\u003C/p\u003E\n\u003Cp class=\u0022text-align-justify\u0022\u003EWhen using a manufacturer cascading chart, you can only use a cascading system by using circuit breakers from the same manufacturer. When implementing the cascading of circuit breakers, it is important to follow the guidelines that are set in SANS 10142-1:2020. An example of a manufacturers\u2019 cascading chart can be seen below.\u003C/p\u003E\n\u003Cp\u003E\u003Ca href=\u0022mailto:hello@magnetgroup.co.za?subject=Schneider Enquiry\u0022\u003E\u003Cimg alt=\u0022Example of cascading chart\u0022 data-entity-type=\u0022file\u0022 data-entity-uuid=\u0022b060ad9d-b785-4996-acde-d4a61705d8c3\u0022 src=\u0022/cms/drupal8-magnetgroup/sites/default/files/inline-images/Example%20of%20cascading%20chart.png\u0022 class=\u0022align-center\u0022 /\u003E\u003C/a\u003E\u003C/p\u003E\n\u003Cp\u003EIn the second instalment of this series, we touch on the topic of selectivity by giving an overview on how it can be enhanced in your system by the implementation of cascading circuit breakers.\u003C/p\u003E\n\u003Cp\u003E\u003Cstrong\u003EResources:\u003C/strong\u003E\u003C/p\u003E\n\u003Cp\u003E\u003Cstrong\u003E1.\u00A0\u003Ca href=\u0022https://www.magnetgroup.co.za/news-letter.html\u0022\u003ESUBSCRIBE\u003C/a\u003E\u003C/strong\u003E to our newsletters to receive this informative content straight to your inbox\u003C/p\u003E\n\u003Cp\u003E\u003Cstrong\u003E2. \u003Ca href=\u0022https://download.schneider-electric.com/files?p_Doc_Ref=LVPED318033EN\u0022\u003EDOWNLOAD\u003C/a\u003E \u003C/strong\u003Ea selectivity, cascading and co-ordination guide\u003Cstrong\u003E \u00A0\u003C/strong\u003E\u003C/p\u003E\n\u003Cp\u003E\u003Cstrong\u003E3. \u003Ca href=\u0022mailto:hello@magnetgroup.co.za?subject=Circuit%20Breaker%20Enquiry\u0022\u003ECHAT\u003C/a\u003E \u003C/strong\u003Eto our experts for assistance with your circuit breakers\u003C/p\u003E\n\u003Cp\u003E\u00A0\u003C/p\u003E\n\u003Cp\u003E\u003Cstrong\u003E\u003Cu\u003ESources:\u003C/u\u003E\u003C/strong\u003E\u003C/p\u003E\n\u003Cp\u003E\u003Ca href=\u0022https://www.electrical-installation.org/enwiki/Coordination_between_circuit-breakers\u0022\u003Ehttps://www.electrical-installation.org/enwiki/Coordination_between_circuit-breakers\u003C/a\u003E\u003C/p\u003E\n\u003Cp\u003E\u003Ca href=\u0022https://www.se.com/in/en/faqs/FA240587/#:~:text=Cascading%20is%20the%20use%20of,barrier%20against%20short%2Dcircuit%20currents\u0022\u003Ehttps://www.se.com/in/en/faqs/FA240587/#:~:text=Cascading%20is%20the%20use%20of,barrier%20against%20short%2Dcircuit%20currents\u003C/a\u003E.\u003C/p\u003E\n\u003Cp\u003E\u003Ca href=\u0022https://www.linkedin.com/pulse/everything-you-need-know-cascading-boris-fuchs/\u0022\u003Ehttps://www.linkedin.com/pulse/everything-you-need-know-cascading-boris-fuchs/\u003C/a\u003E\u003C/p\u003E\n", "created": "Oct 2021", "terms": "Electrical, Education, Schneider" }, { "title": "LEARN | Cascading of Circuit Breakers pt 2", "nid": "555", "body": "\u003Cp\u003E\u003Ca href=\u0022https://www.magnetgroup.co.za/solutions-electrical/index.php\u0022\u003E\u003Cimg alt=\u0022Circuit breakers\u0022 data-entity-type=\u0022file\u0022 data-entity-uuid=\u0022ceaff044-55aa-4f76-88a8-1a7bc72ae240\u0022 height=\u0022179\u0022 src=\u0022/cms/drupal8-magnetgroup/sites/default/files/inline-images/Newsletter.png\u0022 width=\u0022318\u0022 class=\u0022align-center\u0022 /\u003E\u003C/a\u003E\u003C/p\u003E\n\u003Cp class=\u0022text-align-justify\u0022\u003EIn our latest series, we\u2019re discussing the cascading of circuit breakers.\u003C/p\u003E\n\u003Cp class=\u0022text-align-justify\u0022\u003EIn \u003Ca href=\u0022https://www.magnet.co.za/solutions-electrical/news.html?type=article\u0026amp;name=LEARN--Cascading-of-Circuit-Breakers-pt-1\u0022\u003E\u003Cstrong\u003EPart 1\u003C/strong\u003E\u003C/a\u003E, we give an explanation of what cascading is, its advantages, and the conditions required to implement cascading.\u003C/p\u003E\n\u003Cp class=\u0022text-align-justify\u0022\u003EThis second and final instalment in the series touches on the topic of selectivity, by giving an overview on how it can be enhanced in your system by the implementation of cascading circuit breakers.\u003C/p\u003E\n\u003Cp\u003E\u003Cfigure role=\u0022group\u0022 class=\u0022caption caption-img align-center\u0022\u003E\n\u003Ca href=\u0022https://shop.magnetgroup.co.za/\u0022\u003E\u003Cimg alt=\u0022Typical cascading\u0022 data-entity-type=\u0022file\u0022 data-entity-uuid=\u0022202b437f-6389-4772-8c02-7695aa3b5e4e\u0022 height=\u0022329\u0022 src=\u0022/cms/drupal8-magnetgroup/sites/default/files/inline-images/Typical%20Cascading%20Distribution%20Panel.png\u0022 width=\u0022537\u0022 /\u003E\u003C/a\u003E\n\u003Cfigcaption\u003ETypical Cascading Distribution Panel\u003C/figcaption\u003E\n\u003C/figure\u003E\n\u003C/p\u003E\n\u003Cp\u003E\u003Cstrong\u003EWhat does Cascading with Enhanced Discrimination of Circuit Breakers mean?\u003C/strong\u003E\u003C/p\u003E\n\u003Col\u003E\n\u003Cli\u003EIt is the selection of Circuit Breakers to guarantee the Circuit Breaker closest to the fault is the ONLY Breaker to isolate a fault.\u003C/li\u003E\n\u003Cli\u003EThis selection is done by the manufacturers\u2019 cascading with enhanced discrimination charts.\u003C/li\u003E\n\u003Cli\u003EThe MAIN Circuit Breaker in the panel must be double the Amperage of the lower breakers.\u003C/li\u003E\n\u003Cli\u003EThe Circuit Breakers below can be of a much LOWER kA rating to have the cascading effect.\u003C/li\u003E\n\u003Cli\u003EThese systems can be designed and implemented for industrial and utility applications.\u003C/li\u003E\n\u003C/ol\u003E\n\u003Cp\u003E\u003Cfigure role=\u0022group\u0022 class=\u0022caption caption-img align-center\u0022\u003E\n\u003Ca href=\u0022https://www.magnetgroup.co.za/solutions-electrical/index.php\u0022\u003E\u003Cimg alt=\u0022Enhanced discrimination\u0022 data-entity-type=\u0022file\u0022 data-entity-uuid=\u0022e9c6da14-cfda-4254-80eb-20e23e629387\u0022 height=\u0022368\u0022 src=\u0022/cms/drupal8-magnetgroup/sites/default/files/inline-images/Schneider%20-%20Cascading%20with%20enhanced%20discrimination%20chart.png\u0022 width=\u0022682\u0022 /\u003E\u003C/a\u003E\n\u003Cfigcaption\u003ECascading with Enhanced Discrimination Chart (Source: Schneider Electric)\u003C/figcaption\u003E\n\u003C/figure\u003E\n\u003C/p\u003E\n\u003Cp\u003E\u00A0\u003C/p\u003E\n\u003Cp\u003E\u003Cfigure role=\u0022group\u0022 class=\u0022caption caption-img align-center\u0022\u003E\n\u003Cimg alt=\u0022Curves\u0022 data-entity-type=\u0022file\u0022 data-entity-uuid=\u0022fa84e628-1cff-4f42-873c-df40e5a2cdba\u0022 src=\u0022/cms/drupal8-magnetgroup/sites/default/files/inline-images/Curves.png\u0022 /\u003E\n\u003Cfigcaption\u003ECurves of Cascading Breakers vs. Curves of Cascading with Enhanced Discrimination of Breakers\u003C/figcaption\u003E\n\u003C/figure\u003E\n\u003C/p\u003E\n\u003Cp\u003E\u003Cstrong\u003EWhat is Selectivity?\u003C/strong\u003E\u003C/p\u003E\n\u003Cp class=\u0022text-align-justify\u0022\u003ESelectivity is performed with the use of overcurrent and earth fault protection devices. If a fault condition occurs at any point of the installation, it should be cleared by the protective device that is located immediately upstream of the fault, whilst the other protective devices remain unaffected. Refer to Figure 1 below.\u00A0\u003C/p\u003E\n\u003Cp\u003ESelectivity is a requirement for an installation that supplies a critical load, where a fault on one circuit should not cause an interruption on the supply of other circuits. To achieve selectivity, it is vital that the maximum short-circuit current at a point of the installation be less than the selectivity limit of the circuit breakers that supply that point of the installation.\u003C/p\u003E\n\u003Cp\u003ESelectivity is required to be checked for all circuits that are supplied by one source and for the following faults:\u003C/p\u003E\n\u003Col\u003E\n\u003Cli\u003EOverload Faults\u003C/li\u003E\n\u003Cli\u003EShort-Circuit Faults\u003C/li\u003E\n\u003Cli\u003EEarth Faults\u003C/li\u003E\n\u003C/ol\u003E\n\u003Cp\u003E\u003Cstrong\u003EWhat is Current Based Selectivity?\u003C/strong\u003E\u003C/p\u003E\n\u003Cp\u003ECurrent based selectivity is performed by allowing successive tripping thresholds, at stepped levels from downstream circuits that have a lower setting, towards the source which has a higher setting. Refer to Figures 2 to 4 below.\u003C/p\u003E\n\u003Cp\u003E\u003Ca href=\u0022mailto:hello@magnetgroup.co.za?subject=Electrical Enquiry\u0022\u003E\u003Cimg alt=\u0022Figures\u0022 data-entity-type=\u0022file\u0022 data-entity-uuid=\u0022be7cd6d6-c865-43f4-a23c-c1d9488e2bfb\u0022 height=\u0022488\u0022 src=\u0022/cms/drupal8-magnetgroup/sites/default/files/inline-images/Figures%201%20-%204.png\u0022 width=\u0022699\u0022 class=\u0022align-center\u0022 /\u003E\u003C/a\u003E\u003C/p\u003E\n\u003Cp\u003E\u003Cstrong\u003EWhat is Time Based Selectivity?\u003C/strong\u003E\u003C/p\u003E\n\u003Cp\u003ETime based selectivity is obtained by adjusting the time-delayed tripping units so that the relays downstream have the shortest operating times with progressively longer delays towards the source. As seen in the picture below, the upstream circuit breaker A is delayed sufficiently to ensure total selectivity with circuit breaker B.\u003C/p\u003E\n\u003Cp\u003E\u003Cfigure role=\u0022group\u0022 class=\u0022caption caption-img align-center\u0022\u003E\n\u003Cimg alt=\u0022Time based selectivity\u0022 data-entity-type=\u0022file\u0022 data-entity-uuid=\u002287875529-d44c-48a8-960e-ffd6e2fd0233\u0022 src=\u0022/cms/drupal8-magnetgroup/sites/default/files/inline-images/Time%20based%20selectivity.png\u0022 /\u003E\n\u003Cfigcaption\u003EFig 5: Time Based Selectivity between Breakers A and B\u003C/figcaption\u003E\n\u003C/figure\u003E\n\u003C/p\u003E\n\u003Cp\u003E\u00A0\u003C/p\u003E\n\u003Cp\u003E\u003Ca href=\u0022https://www.magnetgroup.co.za/solutions-electrical/index.php\u0022\u003E\u003Cimg alt=\u0022Example of selectivity\u0022 data-entity-type=\u0022file\u0022 data-entity-uuid=\u00223787a47d-a50e-405d-a77c-f69aa505c9cd\u0022 src=\u0022/cms/drupal8-magnetgroup/sites/default/files/inline-images/Selectivity%20example.png\u0022 class=\u0022align-center\u0022 /\u003E\u003C/a\u003E\u003C/p\u003E\n\u003Cp\u003EThe above diagram is a practical example of selectivity using circuit breakers.\u00A0\u003C/p\u003E\n\u003Cp\u003E\u003Cstrong\u003EHow is Selectivity Enhanced by Cascading?\u003C/strong\u003E\u003C/p\u003E\n\u003Cp\u003ECascading between two circuit breakers is performed by using the tripping of the upstream circuit breaker A, to assist circuit breaker B to break the current.\u003C/p\u003E\n\u003Cp\u003EThe principle for this is as follows:\u003C/p\u003E\n\u003Cul\u003E\n\u003Cli\u003EIn the event of the downstream circuit breaker B seeing a very high magnitude short-circuit current. The tripping action will be very fast (\u0026lt;1 ms) which will result in the current being limited.\u003C/li\u003E\n\u003Cli\u003EThe circuit breaker (A), which is located upstream, will see a limited short-circuit current when compared to its breaking capability, but this current will induce a repulsion of the contacts. It will subsequently result in the arcing voltage increasing the current limitation. This arc energy will not be high enough to induce the tripping of the circuit breaker. Thus, circuit breaker A will assist circuit breaker B to trip, without tripping itself. The selectivity limit can be greater than the rated breaking capacity of circuit breaker B, thus resulting in the selectivity becoming total with a reduced cost of the devices.\u003C/li\u003E\n\u003C/ul\u003E\n\u003Cp\u003E\u003Cstrong\u003EResources:\u003C/strong\u003E\u003C/p\u003E\n\u003Cp\u003E1. Do you enjoy reading our articles? \u003Cstrong\u003E\u003Ca href=\u0022https://www.magnetgroup.co.za/news-letter.html\u0022\u003ESUBSCRIBE\u003C/a\u003E\u003C/strong\u003E to get these straight to your inbox!\u003C/p\u003E\n\u003Cp\u003E2. \u003Cstrong\u003E\u003Ca href=\u0022https://download.schneider-electric.com/files?p_Doc_Ref=LVPED318033EN\u0022\u003EDOWNLOAD\u003C/a\u003E\u003C/strong\u003E a selectivity, cascading and co-ordination guide\u00A0\u003C/p\u003E\n\u003Cp\u003E3. Need advice on a product? \u003Cstrong\u003E\u003Ca href=\u0022mailto:hello@magnetgroup.co.za?subject=Circuit%20Breaker%20Enquiry\u0022\u003ECHAT\u003C/a\u003E\u003C/strong\u003E to our team for more on circuit breakers.\u003C/p\u003E\n\u003Cp\u003E\u00A0\u003C/p\u003E\n\u003Cp\u003E\u00A0\u003C/p\u003E\n\u003Cp\u003E\u003Cstrong\u003ESources:\u003C/strong\u003E\u003C/p\u003E\n\u003Cp\u003E\u003Ca href=\u0022https://www.electrical-installation.org/enwiki/Coordination_between_circuit-breakers\u0022\u003Ehttps://www.electrical-installation.org/enwiki/Coordination_between_circuit-breakers\u003C/a\u003E\u003C/p\u003E\n\u003Cp\u003E\u003Ca href=\u0022https://www.se.com/in/en/faqs/FA240587/#:~:text=Cascading%20is%20the%20use%20of,barrier%20against%20short%2Dcircuit%20currents\u0022\u003Ehttps://www.se.com/in/en/faqs/FA240587/#:~:text=Cascading%20is%20the%20use%20of,barrier%20against%20short%2Dcircuit%20currents\u003C/a\u003E.\u003C/p\u003E\n\u003Cp\u003E\u003Ca href=\u0022https://www.linkedin.com/pulse/everything-you-need-know-cascading-boris-fuchs/\u0022\u003Ehttps://www.linkedin.com/pulse/everything-you-need-know-cascading-boris-fuchs/\u003C/a\u003E\u003C/p\u003E\n\u003Cp\u003E\u00A0\u003C/p\u003E\n\u003Cp\u003E\u00A0\u003C/p\u003E\n", "created": "Oct 2021", "terms": "Electrical, Education, Schneider" }, { "title": "READ | Why thermal imaging is good for your business", "nid": "557", "body": "\u003Cp\u003E\u003Ca href=\u0022https://www.magnetgroup.co.za/solutions-electrical/index.php\u0022\u003E\u003Cimg alt=\u0022fluke thermal imaging\u0022 data-entity-type=\u0022file\u0022 data-entity-uuid=\u0022f56d80c3-3907-474c-a280-5a4281c8a5d5\u0022 height=\u0022265\u0022 src=\u0022/cms/drupal8-magnetgroup/sites/default/files/inline-images/Fluke%20image.png\u0022 width=\u0022473\u0022 class=\u0022align-center\u0022 /\u003E\u003C/a\u003E\u003C/p\u003E\n\u003Cp\u003E\u003Cstrong\u003EDue to technology advancements, thermal imaging has become more affordable, easier to use and more broadly deployed in a variety of industrial and commercial markets.\u003C/strong\u003E That is good news if you\u2019re a contractor looking to add thermal imaging to your range of services, because most customers have likely heard of it.\u003C/p\u003E\n\u003Cp\u003EThermal cameras produce thermal (heat) pictures of equipment, allowing your customers to see nearly immediate benefits from such a service. In one pass through a facility, you can usually find at least one component displaying indications the equipment may soon fail. \u003Cstrong\u003EThis makes for a powerful demonstration and an easy business builder.\u003C/strong\u003E\u003C/p\u003E\n\u003Cp\u003EYour advantage as a contractor is having broad experience with many types of equipment and failure scenarios\u2014just like any other troubleshooting situation, the person behind the thermal camera needs to draw on experience to help analyse the readings. \u201CIf this part of an electrical panel is hot, should I investigate the connections or the load?\u201D\u003C/p\u003E\n\u003Cp\u003E\u003Cstrong\u003EIn addition, if you\u2019re already contracted with a company for regular maintenance and troubleshooting, adding thermography makes sense.\u003C/strong\u003E You already know the facility and which units are critical to performance. You can simply add thermal inspections to your regular visits and have the tool available during troubleshooting calls. Plus, if you are an electrician, you\u2019re uniquely qualified to work in live voltage situations. Specialty thermographers often are not qualified and require assistance from an on-site electrician, technician or engineer.\u003C/p\u003E\n\u003Cp\u003E\u003Cstrong\u003EBefore thermal imaging becomes part of your services, explore courses from a reputable trainer.\u003C/strong\u003E Not only will having a credential to point out to prospective clients be beneficial, you will learn the theoretical and practical tools needed to get the best results out of a thermal camera.\u003C/p\u003E\n\u003Cp class=\u0022text-align-justify\u0022\u003EIndeed, training is an important consideration when starting any new initiative.\u003C/p\u003E\n\u003Cp\u003E\u003Cstrong\u003ELook to be trained on:\u003C/strong\u003E\u003C/p\u003E\n\u003Cul\u003E\n\u003Cli\u003EHow to use the thermal camera\u003C/li\u003E\n\u003Cli\u003EApplications with the greatest return on investment\u003C/li\u003E\n\u003Cli\u003EHow to properly perform inspections\u003C/li\u003E\n\u003Cli\u003EHow to interpret results and generate meaningful and actionable reports\u003C/li\u003E\n\u003Cli\u003EHow to safely conduct thermography inspections in an industrial work environment\u00A0\u003C/li\u003E\n\u003C/ul\u003E\n\u003Cp\u003E\u003Cimg alt=\u0022Fluke fig 1\u0022 data-entity-type=\u0022file\u0022 data-entity-uuid=\u00227255892f-e888-4252-a634-90c356326324\u0022 height=\u0022181\u0022 src=\u0022/cms/drupal8-magnetgroup/sites/default/files/inline-images/Figure%201_0.JPG\u0022 width=\u0022588\u0022 class=\u0022align-center\u0022 /\u003E\u003C/p\u003E\n\u003Cp\u003E\u003Cstrong\u003ETypical applications\u003C/strong\u003E\u003C/p\u003E\n\u003Cp\u003EElectrical contractors typically use thermal cameras for preventive maintenance and troubleshooting, and sometimes during installation.\u003C/p\u003E\n\u003Cp\u003E\u003Cstrong\u003EFor preventive maintenance, the contractor takes thermal images of key units (panels, drives, motors, etc.) at least once a year if not more often, and compares those images with each visit.\u003C/strong\u003E Hot spots that weren\u2019t there last time indicate problems in the making to investigate before they cause failure. Software on the thermal imager helps you align your images time after time, so that you\u2019re making consistent comparisons.\u003C/p\u003E\n\u003Cp\u003E\u003Ca href=\u0022mailto:hello@magnetgroup.co.za?subject=Fluke Enquiry\u0022\u003E\u003Cimg alt=\u0022Fluke fig 2\u0022 data-entity-type=\u0022file\u0022 data-entity-uuid=\u002291e6175d-2725-4b8b-9545-70884e88efda\u0022 height=\u0022192\u0022 src=\u0022/cms/drupal8-magnetgroup/sites/default/files/inline-images/Figure%202.JPG\u0022 width=\u0022647\u0022 class=\u0022align-center\u0022 /\u003E\u003C/a\u003E\u003C/p\u003E\n\u003Cp\u003E\u003Cstrong\u003ESome additional things to consider:\u003C/strong\u003E\u003C/p\u003E\n\u003Cul\u003E\n\u003Cli\u003EMost equipment\u2019s failure mechanisms involve a significant rise in operating temperature long before catastrophic failure occurs.\u003C/li\u003E\n\u003Cli\u003EThermal images are best taken while equipment is operational. No shutdowns needed.\u003C/li\u003E\n\u003Cli\u003EThermal images are taken at a safe distance. Minimal safety risk (except for live voltage\u2014that still requires full electrical safety precautions).\u003C/li\u003E\n\u003Cli\u003EThermal images can access components and units not otherwise measurable, such as ceiling runs.\u003C/li\u003E\n\u003Cli\u003EThermal measurements help detect imminent failures in nearly all types of equipment, from electrical to mechanical, process, electronic, and so on.\u003C/li\u003E\n\u003Cli\u003EBecause thermal inspections are fast, they can cover more ground and find problems in areas that would typically be ignored.\u003C/li\u003E\n\u003C/ul\u003E\n\u003Cp\u003E\u003Cstrong\u003EFor troubleshooting, taking a thermal image of a malfunctioning unit can often identify the source of the problem\u003C/strong\u003E\u2014electrical hotspots can tell you which phase or connectors to check, motor hotspots can narrow it down to bearings, and so forth. Then, after repairs, follow up with another thermal image and verify that the component is no longer overheating\u2014or that something else isn\u2019t now overheating, instead.\u003C/p\u003E\n\u003Cp\u003E\u003Cstrong\u003EHere\u2019s a summary of principle applications.\u003C/strong\u003E\u003C/p\u003E\n\u003Cul\u003E\n\u003Cli\u003EElectrical power distribution systems: Three-phase systems, distribution panels, fuses, wiring and connections, substations, electrical vaults, etc.\u003C/li\u003E\n\u003Cli\u003EElectro-mechanical equipment: Motors, pumps, fans, compressors, bearings, windings, gear boxes, and conveyors\u003C/li\u003E\n\u003Cli\u003EProcess instrumentation: Process control equipment, pipes, valves, steam traps and tanks/vessels\u003C/li\u003E\n\u003Cli\u003EFacility maintenance: HVAC systems, buildings, roofs, insulation\u003C/li\u003E\n\u003C/ul\u003E\n\u003Cp\u003E\u003Cstrong\u003ESummary\u003C/strong\u003E\u003C/p\u003E\n\u003Cp\u003EReally, there\u2019s nothing holding you back. Contractors can readily purchase affordable thermal cameras, quickly train on the basics, and immediately start using the tool to improve their client services. The more you use it, the more skilled you become.\u003C/p\u003E\n\u003Cp\u003ENeed advice? \u003Cstrong\u003E\u003Ca href=\u0022mailto:hello@magnetgroup.co.za?subject=Fluke%20Enquiry\u0022\u003ECHAT\u003C/a\u003E\u003C/strong\u003E to us about the FLUKE range of thermal imaging solutions.\u003C/p\u003E\n\u003Cp\u003E\u00A0\u003C/p\u003E\n", "created": "Oct 2021", "terms": "Electrical, Education, Fluke, General" }, { "title": "LEARN | Understanding 3-Phase Transformers pt 3 (continued)", "nid": "545", "body": "\u003Cp class=\u0022text-align-justify\u0022\u003EWelcome to your comprehensive guide on Transformers. Before you get started on the final instalment, why not take a moment to catch up on all the articles in this interesting series:\u003C/p\u003E\n\u003Cp class=\u0022text-align-justify\u0022\u003E\u003Ca href=\u0022https://www.magnetgroup.co.za/news.php?type=articles\u0026amp;name=LEARN--Understanding-3-Phase-Transformers-pt-1\u0022\u003E\u003Cstrong\u003EPart 1: Understanding Transformers and how they work\u003C/strong\u003E\u003C/a\u003E\u003C/p\u003E\n\u003Cp class=\u0022text-align-justify\u0022\u003E\u003Cstrong\u003E\u003Ca href=\u0022https://www.magnetgroup.co.za/solutions-electrical/news.php?type=articles\u0026amp;name=LEARN--Understanding-3-Phase-Transformers-pt-2\u0022\u003EPart 2: Advantages, disadvantages and types of 3-Phase Transformers\u003C/a\u003E\u003C/strong\u003E\u003C/p\u003E\n\u003Cp class=\u0022text-align-justify\u0022\u003E\u003Cstrong\u003E\u003Ca href=\u0022https://www.magnetgroup.co.za/news.php?type=articles\u0026amp;name=LEARN--Understanding-3-Phase-Transformers-pt-3\u0022\u003EPart 3: \u003C/a\u003E\u003C/strong\u003E\u003C/p\u003E\n\u003Cul\u003E\n\u003Cli class=\u0022text-align-justify\u0022\u003E\u003Cstrong\u003E\u003Ca href=\u0022https://www.magnetgroup.co.za/news.php?type=articles\u0026amp;name=LEARN--Understanding-3-Phase-Transformers-pt-3\u0022\u003EProtection Schemes for Oil Type Transformers\u003C/a\u003E\u003C/strong\u003E\u003C/li\u003E\n\u003Cli class=\u0022text-align-justify\u0022\u003EProtection Schemes for Oil Type Transformers\u00A0continued\u003C/li\u003E\n\u003C/ul\u003E\n\u003Cp\u003E\u003Ca href=\u0022mailto:hello@magnetgroup.co.za?subject=Electrical Enquiry\u0022\u003E\u003Cimg alt=\u0022Oil type transformer\u0022 data-entity-type=\u0022file\u0022 data-entity-uuid=\u0022ae982d7a-2777-4fa8-a837-9e2c228ca28e\u0022 height=\u0022229\u0022 src=\u0022/cms/drupal8-magnetgroup/sites/default/files/inline-images/Oil-Filled-Transformers_0.jpg\u0022 width=\u0022345\u0022 class=\u0022align-center\u0022 /\u003E\u003C/a\u003E\u003C/p\u003E\n\u003Cp class=\u0022text-align-justify\u0022\u003E\u00A0\u003C/p\u003E\n\u003Cp class=\u0022text-align-justify\u0022\u003EWe\u2019re wrapping up our series with a second instalment on Protection Schemes for Oil Type Transformers. In this article, we give a basic introduction to the Buchholz relay, its principle of operation, the advantages, and the limitations of having this vital piece of equipment installed on oil-type transformers. This articles also gives a brief explanation of the devices that are used to monitor the oil level and the temperature of the hottest part of the winding in your transformer.\u003C/p\u003E\n\u003Cp class=\u0022text-align-justify\u0022\u003E\u003Cstrong\u003EBuchholz Relay\u003C/strong\u003E\u003C/p\u003E\n\u003Cp class=\u0022text-align-justify\u0022\u003EA Buchholz relay is an oil and gas actuated protection relay that is implemented on oil immersed transformers. It is used for the protection of transformers from faults that occur inside it. Short circuit faults, inter-turn faults, incipient winding faults and core faults occur because of an impulse breakdown occurring on the insulating oil or deterioration in the transformer oil itself.\u00A0 The Buchholz relay will sense these faults, and issue a trip signal to the circuit breaker which is either on the HV or LV side of the transformer. This will then enable the circuit breaker to isolate the faulted zone.\u003C/p\u003E\n\u003Cp\u003E\u003Cfigure role=\u0022group\u0022 class=\u0022caption caption-img align-center\u0022\u003E\n\u003Ca href=\u0022mailto:hello@magnetgroup.co.za?subject=Electrical Enquiry\u0022\u003E\u003Cimg alt=\u0022Buchholz\u0022 data-entity-type=\u0022file\u0022 data-entity-uuid=\u00228b32d9b5-ef17-481e-9243-8abbbaa543df\u0022 src=\u0022/cms/drupal8-magnetgroup/sites/default/files/inline-images/Figure%201_0.png\u0022 /\u003E\u003C/a\u003E\n\u003Cfigcaption\u003EBuchholz Relay and Conservator Location on an Oil-Filled Transformer\u003C/figcaption\u003E\n\u003C/figure\u003E\n\u003C/p\u003E\n\u003Cp class=\u0022text-align-justify\u0022\u003E\u003Cstrong\u003EPrinciple of Operation\u003C/strong\u003E\u003C/p\u003E\n\u003Cp class=\u0022text-align-justify\u0022\u003EA fault that occurs in the transformer will cause the oil in the tank to become overheated, thus producing gas. The generation of the gas in the transformer is dependent on the intensity of the fault that occurred. As a result of this heat, oil in the tank will decompose, and this is used to detect winding faults. The gas then flows in an upward direction and gets collected in the Buchholz relay. This gas decomposes the oil in the Buchholz relay, and this displacement is equivalent to the volume of gas collected. The displacement of oil will result in the upper float closing the upper mercury switch that is connected to an alarm circuit. Therefore, when minor faults occur, the alarm gets activated. The amount of gas that is collected will indicate the severity of the fault. The lower float is unaffected by minor faults as there is not enough gas to move it.\u00A0\u00A0\u003C/p\u003E\n\u003Cp class=\u0022text-align-justify\u0022\u003EA major fault, such as a phase to earth short circuit, will generate a vast amount of heat resulting in a large amount of gas being produced. This gas will also flow in an upward direction but the motion of it will be high enough to tilt the lower float in a Buchholz relay. In the event of a major fault, the lower float will cause the lower mercury switch to trip the transformer from the supply.\u003C/p\u003E\n\u003Cp\u003E\u003Cfigure role=\u0022group\u0022 class=\u0022caption caption-img align-center\u0022\u003E\n\u003Ca href=\u0022mailto:hello@magnetgroup.co.za?subject=Electrical Enquiry\u0022\u003E\u003Cimg alt=\u0022CS Diagram of Buccholz\u0022 data-entity-type=\u0022file\u0022 data-entity-uuid=\u00221940d2c8-c611-4eb6-8c57-c91ce11b7cca\u0022 src=\u0022/cms/drupal8-magnetgroup/sites/default/files/inline-images/Figure%202_0.png\u0022 /\u003E\u003C/a\u003E\n\u003Cfigcaption\u003ECross Section Diagram of a Buchholz Relay\u003C/figcaption\u003E\n\u003C/figure\u003E\n\u003C/p\u003E\n\u003Cp class=\u0022text-align-justify\u0022\u003E\u003Cstrong\u003EAdvantages of a Buchholz Relay\u003C/strong\u003E\u003C/p\u003E\n\u003Col\u003E\n\u003Cli class=\u0022text-align-justify\u0022\u003EIndicates internal faults that may occur due to heating and helps avoid major faults\u003C/li\u003E\n\u003Cli class=\u0022text-align-justify\u0022\u003EDetermines the severity of a fault without dismantling a transformer\u003C/li\u003E\n\u003Cli class=\u0022text-align-justify\u0022\u003EIsolates a transformer if a major fault occurs, thus preventing accidents\u003C/li\u003E\n\u003C/ol\u003E\n\u003Cp class=\u0022text-align-justify\u0022\u003E\u003Cstrong\u003ELimitations of the Buchholz Relay\u003C/strong\u003E\u003C/p\u003E\n\u003Col\u003E\n\u003Cli class=\u0022text-align-justify\u0022\u003EOnly implemented in an oil immersed transformer\u003C/li\u003E\n\u003Cli class=\u0022text-align-justify\u0022\u003EOnly detects a fault below the oil level\u003C/li\u003E\n\u003Cli class=\u0022text-align-justify\u0022\u003EOffers no protection for connecting cables, hence separate protection is needed for that\u003C/li\u003E\n\u003Cli class=\u0022text-align-justify\u0022\u003EHigh response time (the minimum operating time of the relay is 0.1 seconds)\u003C/li\u003E\n\u003C/ol\u003E\n\u003Cp class=\u0022text-align-justify\u0022\u003E\u003Cstrong\u003EOil Level Monitoring Device\u003C/strong\u003E\u003C/p\u003E\n\u003Cp class=\u0022text-align-justify\u0022\u003EA transformer that has an oil conservator will often have an oil level monitor installed. This monitor has two contacts for an alarm. One contact is used for the maximum oil level alarm and the other contact is for the minimum oil level alarm.\u003C/p\u003E\n\u003Cp\u003E\u003Cfigure role=\u0022group\u0022 class=\u0022caption caption-img align-center\u0022\u003E\n\u003Cimg alt=\u0022Oil level monitor\u0022 data-entity-type=\u0022file\u0022 data-entity-uuid=\u002215eb9d53-8f16-4375-a205-ea8abb6afcd4\u0022 src=\u0022/cms/drupal8-magnetgroup/sites/default/files/inline-images/Figure%203.png\u0022 /\u003E\n\u003Cfigcaption\u003EOil Level Monitor\u003C/figcaption\u003E\n\u003C/figure\u003E\n\u003C/p\u003E\n\u003Cp class=\u0022text-align-justify\u0022\u003EA top-oil thermometer consists of a liquid thermometer bulb that is in a pocket at the top of the transformer. The thermometer is used to measure the top-oil temperature of the transformer. This thermometer can have one to four contacts that sequentially close at successively higher temperatures.\u003C/p\u003E\n\u003Cp class=\u0022text-align-justify\u0022\u003E\u003Cstrong\u003EWinding Thermometers\u003C/strong\u003E\u003C/p\u003E\n\u003Cp class=\u0022text-align-justify\u0022\u003EA winding thermometer is a device that responds to both the top-oil temperature and the heating effect of the load current. A winding thermometer leads to the creation of an image that depicts the hottest part of the winding. This top-oil temperature is measured by the procedure mentioned above, but this measurement is expanded with a current signal that is proportional to the loading current in the winding.\u003C/p\u003E\n\u003Cp class=\u0022text-align-justify\u0022\u003EThe current signal is taken from a current transformer that is installed in the bushing of that winding. A resistor element is fed with this current, causing it to heat up, thus heating up the measurement below and finally resulting in an increased indicator movement.\u003C/p\u003E\n\u003Cp class=\u0022text-align-justify\u0022\u003EThe temperature bias is directly proportional to the resistance of the electric heating (resistor) element. The bias should correspond to the difference between the hot-spot temperature and the top-oil temperature. The time constant of the heating of the pocket should equal the time constant of the heating of the winding. The temperature sensor will then measure a temperature that is equal to the winding temperature, if the bias is equal to the temperature difference and the constants are equal.\u003C/p\u003E\n\u003Cp class=\u0022text-align-justify\u0022\u003ENeed advice on your transformer?\u00A0\u003Cstrong\u003E\u003Ca href=\u0022mailto:hello@magnetgroup.co.za?subject=Electrical%20Enquiry\u0022\u003ECHAT\u003C/a\u003E\u003C/strong\u003E\u00A0to us now!\u003C/p\u003E\n", "created": "Sep 2021", "terms": "Electrical, Education" } ]