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Industrial and Commercial Power System Harmonic Studies INDUSTRIAL AND COMMERCIAL POWER SYSTEM HARMONIC STUDIES Copyright Material PCIC Paper No. 388 PCIC Middle East 2019 JJ Dai, PhD, PE, SIEEE Eaton Corporation Barranca Pkwy, Suite C-10, Irvine, CA USA Abstract -- This paper reviews the latest IEEE Std. 3002.8 “Recommended Practice for Conducting Harmonic Analysis Studies of Industrial and Commercial Power Systems”. The standard is based on IEEE Std. 399 (Brown Book) with many new enhancements and G additions. The new standard systematically addresses requirements and recommendations for performing power system harmonic studies, including developing system Electronic M Blaster models, modeling various harmonic sources and electrical M Welder equipment and devices, preparing required data for UPS modeling and studies, validating model and data, M selecting study cases, and analyzing results and outputs Battery from the studies. Necessary features for computer tools that are used to perform harmonic-analysis are listed and discussed. The latest IEEE Std. 519-2014 Fig. 1. Sample industrial power system with multiple “Recommended Practices and Requirements for harmonic sources Harmonic Control in Electrical Power Systems” is referenced in the standard, as well as references related After twenty-one years, IEEE recommended practice to interharmonics. One illustration example is provided at for conducting harmonic study in industrial and end of the paper to help readers further understand commercial power systems has been updated. The harmonic studies and expected results. The author of this previous standard was IEEE Standard 399 “IEEE paper is the co-chair of IEEE Std. 3002.8 working group. Recommended Practice for Industrial and Commercial Power Systems Analysis (also known as Brown Book)” Index Terms — Industrial and commercial power [1], published in 1997. Per IEEE decision, Chapter 10 of systems, Power system analysis and computing, the Brown Book “Harmonic analysis studies” is converted Harmonics, Harmonic distortions, Harmonic limits, into an independent dot standard of IEEE Standard Harmonic modeling and study. 3002.8 “Recommended Practice for Conducting Harmonic Analysis Studies of Industrial and Commercial Power I. INTRODUCTION Systems” [2]. The new standard provides detailed practice on how to conduct harmonic studies and analysis of Devices with nonlinear voltage-current characteristics industrial and commercial power systems. It discusses generate harmonics. The main sources of harmonics in basic concepts for harmonic study, the need for the study, industrial and commercial power systems are static power required data for analysis, study methodologies, converters used as rectifiers for various industrial recognition of potential problems, corrective measures, applications such as adjustable speed drives (ASD), and benefits of using a computer as a tool in a harmonic- uninterruptible power system (UPS), chargers, switched- analysis studies. mode supplies, static frequency converter, cycloconverters, etc. Arc furnaces and saturated magnetic II. MAIN CHANGES IN NEW STANDARD devices are also harmonic sources. A sample industrial power system with multiple harmonic sources is depicted 3002.8-2018 standard is based on previous IEEE in Fig. 1. Standard 399 “IEEE Recommended Practice for Industrial Since nonlinear devices represent an ever-increasing and Commercial Power Systems Analysis” (Brown Book), percentage of the total load in industrial and commercial published in 1997. electrical power distribution systems, harmonic studies Chapter 10 “Harmonic analysis studies” of the Brown become an important part of overall system design and Book has 48 pages, and 3002.8-2018 contains 76 pages. operation. By modeling power system impedances as a Comparison of contents between Chapter 10 of the function of frequency and harmonic sources as injecting Brown Book and 3002.8-2018 are listed in TABLE I: currents or forced voltages, a harmonic study can be made to determine the level and effect of the harmonic TABLE I distortions in the power system. COMPARISON OF CONTENTS IEEE Std. 399-1997 IEEE 3002.8-2018 (Brown Book) n/a Scope n/a Normative references Introduction Introduction Background Background Purpose of harmonic study Analysis objectives 3. To investigate root causes of a system with history General theory Methodology and standards of harmonic-related problems, such as failure of System simulation and power-factor compensation capacitors, System modeling modeling overheating of cables, transformers, motors, etc., n/a Required data or misoperation of protective relays or control Data collection and devices n/a preparation 4. To plan and simulate a system expansion where n/a Model and data validation significant nonlinear loads are added or where a significant amount of capacitance is added n/a Study scenarios 5. To design a new facility or power system where the n/a Solution parameters load flow, power factor compensation, and n/a Results and report harmonic analyses are considered as one n/a Features of analysis tools integrated study Example solutions Illustration examples (included in System B. Benefits Remedial measures (filters) simulation and modeling) (included in Normative Reasons and benefits to conduct harmonic-analysis Harmonic standards references) studies on industrial and commercial power systems References (included in Bibliography) include: Bibliography Bibliography 1. Benchmark existing system and collect data to calibrate the model by measuring the existing As can be seen from Table I that 3002.8-2018 adds system with a well-defined test plan several new sections of required data for studies, 2. Identify location, type, and magnitude of harmonic recommendations to prepare and validate model and sources in the system data, discussions for study cases, and illustrations of 3. Simulate impacts of these harmonic sources on study results and report. It is the intention of the standard system voltages and currents to provide complete guidelines for engineers to 4. Study harmonic penetrations to the system understand detailed procedures and necessary steps to 5. Calculate voltage and current harmonic distortions prepare system models and data to perform harmonic on each individual frequency and Total Harmonic studies. Distortion (THD) In addition to the new sections, 3002.8-2018 also 6. Check if there exists any violations in harmonic addresses a number of important issues including a voltage and current distortion levels discussion on interharmonics and its modeling for studies, 7. Calculate other harmonic indices and compare the latest IEEE Standard 519 “IEEE Recommended them to the standard or code limitations Practice and Requirements for Harmonic Control in 8. Investigate if the system has parallel or series Electric Power Systems”[3] recommended harmonic limits resonance conditions at the interface of an industrial or commercial facility to the 9. Design harmonic filters and test harmonic filters grid, and some useful features such as analyzer and 10. Test transformer phase shift and analyze its effects visual presentations to study results in computer software on harmonic current cancellation and harmonic which can greatly assist engineers in studies. Comparing distortion deduction to the Brown Book there is one sample study case, 11. Test other harmonic mitigation designs and 3002.8-2018 provides three illustration cases which performance include the original case from the Brown Book and two new cases, the second case of 13-bus balanced industrial C. Methodology distribution case from IEEE PES Task Force on Harmonics Modeling and Simulation, and the third case is Based on differing phases of a power system, the a composite industrial power system. methodology of conducting harmonic study has different focus. III. OBJECTIVE AND METHODOLOGY 1. Design phase The new standard discusses objectives to perform During system design phase, the following factors are harmonic studies, benefits for the studies, and to be considered in the study: methodology (approach) to conduct the studies in a) Model harmonic sources from nonlinear loads different phases of a system. and powered electronics devices, simulate their A. Objectives impacts, and assess harmonic voltage and current distortion levels The standard lists following situations that may b) Calculate harmonic distortion indices for both necessitate a harmonic study: voltage and current c) Compare distortion levels and harmonic indices 1. To comply with IEEE Std 519, which defines the with the standard and code limits to see if there current distortion limits a user should meet at the are any violations Point of Common Coupling (PCC) with the utility d) Identify system parallel or series resonance 2. To evaluate impact on the system due to utility frequencies voltage harmonic distortion specified in IEEE Std e) Check if there are any harmonic source 519 frequencies at or near the system parallel resonance points is an integer f) If there are harmonic source frequencies at or is the number of pulse near the system parallel resonance points, ͡ ͤ assess the overvoltage conditions at these A sample of harmonic current spectrum from a 6-pulse frequency points ASD at 480 V is measured and listed in the Table II. A g) If there are harmonic source frequencies at or more popular presentation of harmonic content is using a near the system series resonance points, assess spectrum for harmonic magnitude which is shown in Fig. 2 the overcurrent conditions for the same harmonic source in TABLE II h) If necessary, design and test
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