Calculation of the Transient Currents in Transformers using Field-Circuits Methods

Published by Bronisław TOMCZUK, Dariusz KOTERAS, Jan ZIMON, Andrzej WAINDOK Opole University of Technology, Department of Industrial Electrical Engineering Abstract. The Field-Circuit Method (FCM) and the new Modified Time Stepping Finite Element Method (MTSF) as well as classical Time Stepping Finite Element Method (TSF) have been used for the transient current calculations in transformers. TheContinue reading “Calculation of the Transient Currents in Transformers using Field-Circuits Methods”

New Approach to Protecting Transformers Against High Frequency Transients – Wind Turbine Case Study

Published by Dariusz SMUGAŁA(1), Wojciech PIASECKI(1), Magdalena OSTROGÓRSKA(1), Marek FLORKOWSKI(1), Marek FULCZYK(2), Ole GRANHAUG(3), ABB Sp.z.o.o., Corporate Research Center, Cracow, Poland (1), ABB Oy, Medium Voltage Products, Vaasa, Finland (2), ABB AS, Medium Voltage Products, Skien, Norway (3) Abstract. Novel protection method of wind turbine transformers against high frequency transients occurring during switchgear operation isContinue reading “New Approach to Protecting Transformers Against High Frequency Transients – Wind Turbine Case Study”

Transient Performance of Interconnected Wind Turbine Grounding Systems

Published by Blagoja MARKOVSKI, Leonid GRCEV, Vesna ARNAUTOVSKI-TOSEVA, Marija KACARSKA,Ss. Cyril and Methodius University of Skopje, Faculty of Electrical Engineering and Information Technologies Abstract. We analyze the transient grounding characteristics of interconnected wind turbine grounding systems, for fast rising current pulses. By increasing the number of wind turbines, influences on harmonic impedance and transient potentialContinue reading “Transient Performance of Interconnected Wind Turbine Grounding Systems”

How High Voltage PTs (VTs) and CTs Limit the Input to PQ Voltage Transient Measuring Instruments and Limit the High Order Harmonic Accuracies of Voltage and Current

Published by Terry Chandler, Director of Engineering, Power Quality Thailand Ltd. & Power Quality Inc., USA. Application Note, Sept. 2013Emails: terryc@powerquality.org, terryc@powerquality.co.th Typical PTs and CTs cause errors and issues in PQ measurements in three areas: 1. Harmonics As the PT and CT have very poor frequency response, they are in affect are a low pass filter onContinue reading “How High Voltage PTs (VTs) and CTs Limit the Input to PQ Voltage Transient Measuring Instruments and Limit the High Order Harmonic Accuracies of Voltage and Current”

Substation Transformer Switching and Dynamic Overvoltages

Published by Electrotek Concepts, Inc., PQSoft Case Study: Substation Transformer Switching and Dynamic Overvoltages, Document ID: PQS1204, Date: January 26, 2012. Abstract: This case study presents the results for a wind plant substation transformer energizing and dynamic overvoltage evaluation. Transformer inrush currents contain harmonic components that may create dynamic overvoltages if a substation transformer is energizedContinue reading “Substation Transformer Switching and Dynamic Overvoltages”

Temporary Overvoltage and Grounding Transformer Analysis

Published by Electrotek Concepts, Inc., PQSoft Case Study: Temporary Overvoltage and Grounding Transformer Analysis, Document ID: PQS1203, Date: January 25, 2012. Abstract: This case study presents the results for a wind plant temporary overvoltage (TOV) and grounding transformer transient analysis. The case study investigated the potential for excessive temporary overvoltages during single-phase faults on a 34.5Continue reading “Temporary Overvoltage and Grounding Transformer Analysis”

Lightning Transient Overvoltage Evaluation

Published by Electrotek Concepts, Inc., PQSoft Case Study: Lightning Transient Overvoltage Evaluation, Document ID: PQS1205, Date: January 26, 2012. Abstract: This case study presents a wind plant substation lightning transient overvoltage evaluation. A high-frequency transient model was created to simulate the lightning transients and resulting overvoltages and arrester energy duties. A high-frequency model was required toContinue reading “Lightning Transient Overvoltage Evaluation”

The Trouble With Capacitors Part 1

Published by R. Fehr, P.E., Engineering Consultant, Dec 1, 2003 Although shunt capacitors offer several advantages at all voltage levels, those advantages come at a price. Not only must you purchase, install, and maintain capacitor equipment, you must be able to switch it in and out of service to get the most from the system.Continue reading “The Trouble With Capacitors Part 1”

Voltage Magnification and Nuisance Tripping during Capacitor Bank Switching

Published by Electrotek Concepts, Inc., PQSoft Case Study: Voltage Magnification and Nuisance Tripping during Capacitor Bank Switching, Document ID: PQS0902, Date: October 15, 2009. Abstract: The application of utility capacitor banks has long been accepted as a necessary step in the efficient design of utility power systems. In addition, capacitor switching is generally considered a normalContinue reading “Voltage Magnification and Nuisance Tripping during Capacitor Bank Switching”

VCB Current Chopping Evaluation

Published by Electrotek Concepts, Inc., PQSoft Case Study: VCB Current Chopping Evaluation, Document ID: PQS1207, Date: June 1, 2012. Abstract: This case study presents a customer vacuum circuit breaker (VCB) current chopping transient overvoltage evaluation. A high-frequency transient model was created to simulate vacuum circuit breaker opening and closing and the resulting transient overvoltages and arresterContinue reading “VCB Current Chopping Evaluation”