Published by Electrotek Concepts, Inc., PQSoft Case Study: Transformer Energizing and Dynamic Overvoltages, Document ID: PQS0709, Date: October 15, 2007. Abstract: Energizing power transformers results in inrush currents that are rich in harmonic components. The inrush current interacts with the system impedance vs. frequency characteristics to create a voltage waveform that can have significant harmonic componentsContinue reading “Transformer Energizing and Dynamic Overvoltages”
Tag Archives: Transformers
Modeling Ferroresonance in an Underground Distribution System
Published by Electrotek Concepts, Inc., PQSoft Case Study: Modeling Ferroresonance in an Underground Distribution System, Document ID: PQS0610, Date: July 1, 2006. Abstract: The objective of this case study is to provide an overview of ferroresonance phenomena, its modeling aspects, and practical experience in recognizing, avoiding, and solving the problem. In particular, it will present symptomsContinue reading “Modeling Ferroresonance in an Underground Distribution System”
Ferroresonance Analysis – 25kV Single 5-Legged Core Transformer
Published by Electrotek Concepts, Inc., PQSoft Case Study: Ferroresonance Analysis – 25kV Single 5-Legged Core Transformer, Document ID: PQS0318, Date: July 18, 2002. Abstract: Ferroresonance is a concern for medium voltage underground systems. As part of an evaluation of the design of a new 25kV underground system, the potential for ferroresonance was analyzed. Ferroresonance requires aContinue reading “Ferroresonance Analysis – 25kV Single 5-Legged Core Transformer”
K-factor & Transformers
Published by Pacific Crest Transformers, 300 West Antelope Road – Medford, Oregon 97503 Tel : (541) 826 – 2113 Fax : (541) 826 – 8847. March, 2015. Transformers serving heavy nonlinear loads are subject to increased winding temperatures due to the harmonic currents generated by those loads. This overheating can result in a shortened serviceContinue reading “K-factor & Transformers”
Solving and Mitigating Electrical Power Problems
Published by CEA Technologies Inc. (CEATI), POWER QUALITY Energy Efficiency Reference Guide, Chapter 4 – Solving and Mitigating Electrical Power Problems. 4.1 Identifying the Root Cause and Assessing Symptoms Power quality technologists employ technical instrumentation. This instrumentation can range from simple digital multi-metering through to sophisticated waveform analysis instruments. True power quality monitoring requires full-timeContinue reading “Solving and Mitigating Electrical Power Problems”
Am I not safe from harmonics if I use K-Rated transformers and oversized neutrals?
Published by Mirus International Inc., [2010-01-08] MIRUS-FAQ001-B2, FAQ’s Harmonic Mitigating Transformers, 31 Sun Pac Blvd., Brampton, Ontario, Canada. L6S 5P6. K-Rated transformers made their appearance several years ago as a means of preventing transformers from failing when subjected to heavy non-linear loading. They are essentially ‘beefed up’ transformers with extra steel in their cores andContinue reading “Am I not safe from harmonics if I use K-Rated transformers and oversized neutrals?”
How reliable are transformer energy efficiency tests (including Independent 3rd Party) under non-linear loading?
Published by Mirus International Inc., [2010-01-08] MIRUS-FAQ001-B2, FAQ’s Harmonic Mitigating Transformers, 31 Sun Pac Blvd., Brampton, Ontario, Canada. L6S 5P6. It is much more difficult to accurately determine the energy efficiency of a transformer under non-linear loading than it is under linear loading. The industry accepted technique for measuring transformer efficiency under linear load involvesContinue reading “How reliable are transformer energy efficiency tests (including Independent 3rd Party) under non-linear loading?”
What constitutes an EPA Energy Star Transformer and is it important when supplying non-linear loads?
Published by Mirus International Inc., [2010-01-08] MIRUS-FAQ001-B2, FAQ’s Harmonic Mitigating Transformers, 31 Sun Pac Blvd., Brampton, Ontario, Canada. L6S 5P6. The Energy Star program is sponsored by the US Environmental Protection Agency (EPA) and is designed to encourage the use of energy efficient products. The Energy Star logo is found on many household appliances andContinue reading “What constitutes an EPA Energy Star Transformer and is it important when supplying non-linear loads?”
What are zero sequence harmonic filters and how do they reduce 3rd harmonic currents and prevent neutral conductor overheating?
Published by Mirus International Inc., [2010-01-08] MIRUS-FAQ001-B2, FAQ’s Harmonic Mitigating Transformers, 31 Sun Pac Blvd., Brampton, Ontario, Canada. L6S 5P6. Zero sequence currents, in simple terms, are those found in the neutral conductor. They include the unbalanced 60 Hz currents and the 3rd, 9th, 15th and other triplen harmonic currents. Zero sequence currents appear inContinue reading “What are zero sequence harmonic filters and how do they reduce 3rd harmonic currents and prevent neutral conductor overheating?”
How do harmonics increase power losses and overheat transformers?
Published by Mirus International Inc., [2010-01-08] MIRUS-FAQ001-B2, FAQ’s Harmonic Mitigating Transformers, 31 Sun Pac Blvd., Brampton, Ontario, Canada. L6S 5P6. Harmonics generated by non-linear loads substantially increase the losses in conventional or K-rated delta-wye distribution transformers. This increase in losses will increase operating costs and can shorten transformer life. The main thrust of the K-ratedContinue reading “How do harmonics increase power losses and overheat transformers?”
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