{"id":{"repo_id":"vt","oai_identifier":"oai:vtechworks.lib.vt.edu:10919/52247"},"canonical_url":"https://search.dev.ndltd.org/etd/vt/oai:vtechworks.lib.vt.edu:10919/52247","repository":{"repo_id":"vt","name":"Virginia Tech","base_url":"https://vtechworks.lib.vt.edu/oai/request"},"display":{"title":"Impact of System Impedance on Harmonics Produced by Variable Frequency Drives (VFDs)","abstract":"Variable Frequency Drives (VFDs) are utilized in commercial and industrial facilities to improve motor efficiency and provide process flexibility. VFDs are nonlinear loads that inject harmonic currents into the power system, and result in harmonic voltages across the system impedance. This harmonic distortion can negatively impact the performance of other sensitive loads in the system. If a VFD serves a critical function, it may be necessary to supply the VFD from a Diesel Generator or Uninterruptible Power Supply (UPS). These sources have relatively high impedance when compared to a standard utility source, and will result in greater harmonic voltage distortion. This increases the likelihood of equipment failure due to harmonics. The full extent of the impact, however, is typically unknown until an extensive harmonic analysis is performed or the system is installed and tested. This thesis evaluates the impact that source impedance has on the harmonic voltage distortion that is produced by nonlinear loads such as VFDs. An ideal system of varying source types (Utility, Generator and UPS) and varying VFD rectifier technologies (6-Pulse, 12-Pulse and 18-Pulse) is created to perform this analysis and plot the results. The main output of this thesis is a simplified methodology for harmonic analysis that can be implemented when designing a power system with a VFD serving a critical function and a high impedance source like a generator or UPS. Performing this analysis will help to ensure that other sensitive loads will operate properly in the system.","abstract_html":"Variable Frequency Drives (VFDs) are utilized in commercial and industrial facilities to improve motor efficiency and provide process flexibility. VFDs are nonlinear loads that inject harmonic currents into the power system, and result in harmonic voltages across the system impedance. This harmonic distortion can negatively impact the performance of other sensitive loads in the system. If a VFD serves a critical function, it may be necessary to supply the VFD from a Diesel Generator or Uninterruptible Power Supply (UPS). These sources have relatively high impedance when compared to a standard utility source, and will result in greater harmonic voltage distortion. This increases the likelihood of equipment failure due to harmonics. The full extent of the impact, however, is typically unknown until an extensive harmonic analysis is performed or the system is installed and tested. This thesis evaluates the impact that source impedance has on the harmonic voltage distortion that is produced by nonlinear loads such as VFDs. An ideal system of varying source types (Utility, Generator and UPS) and varying VFD rectifier technologies (6-Pulse, 12-Pulse and 18-Pulse) is created to perform this analysis and plot the results. The main output of this thesis is a simplified methodology for harmonic analysis that can be implemented when designing a power system with a VFD serving a critical function and a high impedance source like a generator or UPS. Performing this analysis will help to ensure that other sensitive loads will operate properly in the system.","abstract_has_math":false,"creators":["Morton, Daniel David"],"institution":"Virginia Tech","degree_name":"Master of Science","degree_level":"masters","degree_discipline":"Electrical Engineering","degree_department":"Electrical and Computer Engineering","school":null,"contributors":[],"advisors":[],"committee_chairs":["De La Ree, Jaime"],"committee_members":["Centeno, Virgilio A.","Phadke, Arun G."],"year":2015,"date_issued":"2015-05-11","date_published":"2015-05-11","updated_at":"2026-07-22T22:19:59Z","subjects":["Harmonic Analysis","Power Electronics","Variable Frequency Drives"],"languages":[],"rights":["In Copyright"],"rights_urls":["http://rightsstatements.org/vocab/InC/1.0/"],"identifier_entries":[{"key":"dc:identifier.other","label":"Dc Identifier Other","values":["vt_gsexam:5347"],"render_values":[{"text":"vt_gsexam:5347","href":null,"code":true}]}]},"links":{"outbound_url":"http://hdl.handle.net/10919/52247","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.committeechair","label":"Committee Chair","values":["De La Ree, Jaime"]},{"key":"dc:contributor.committeemember","label":"Committee Member","values":["Centeno, Virgilio A.","Phadke, Arun G."]},{"key":"dc:contributor.department","label":"Department","values":["Electrical and Computer Engineering"]},{"key":"dc:creator","label":"Author","values":["Morton, Daniel David"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2015-05-12T08:00:07Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2015-05-12T08:00:07Z"]},{"key":"dc:date.issued","label":"Date","values":["2015-05-11"]},{"key":"dc:publisher","label":"Institution","values":["Virginia Tech"]},{"key":"dc:type","label":"Dc Type","values":["Thesis"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Electrical Engineering"]},{"key":"thesis:degree_level","label":"Degree Level","values":["masters"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Master of Science"]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["Virginia Polytechnic Institute and State University"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Harmonic Analysis","Power Electronics","Variable Frequency Drives"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:rights","label":"Dc Rights","values":["In Copyright"]},{"key":"dc:rights.uri","label":"Rights URI","values":["http://rightsstatements.org/vocab/InC/1.0/"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.other","label":"Dc Identifier Other","values":["vt_gsexam:5347"]},{"key":"dc:identifier.uri","label":"Identifier URI","values":["http://hdl.handle.net/10919/52247"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["Variable Frequency Drives (VFDs) are utilized in commercial and industrial facilities to improve motor efficiency and provide process flexibility. VFDs are nonlinear loads that inject harmonic currents into the power system, and result in harmonic voltages across the system impedance. This harmonic distortion can negatively impact the performance of other sensitive loads in the system. If a VFD serves a critical function, it may be necessary to supply the VFD from a Diesel Generator or Uninterruptible Power Supply (UPS). These sources have relatively high impedance when compared to a standard utility source, and will result in greater harmonic voltage distortion. This increases the likelihood of equipment failure due to harmonics. The full extent of the impact, however, is typically unknown until an extensive harmonic analysis is performed or the system is installed and tested. This thesis evaluates the impact that source impedance has on the harmonic voltage distortion that is produced by nonlinear loads such as VFDs. An ideal system of varying source types (Utility, Generator and UPS) and varying VFD rectifier technologies (6-Pulse, 12-Pulse and 18-Pulse) is created to perform this analysis and plot the results. The main output of this thesis is a simplified methodology for harmonic analysis that can be implemented when designing a power system with a VFD serving a critical function and a high impedance source like a generator or UPS. Performing this analysis will help to ensure that other sensitive loads will operate properly in the system."]},{"key":"dc:description.degree","label":"Dc Description Degree","values":["Master of Science"]},{"key":"dc:format.medium","label":"Dc Format Medium","values":["ETD"]},{"key":"dc:title","label":"Title","values":["Impact of System Impedance on Harmonics Produced by Variable Frequency Drives (VFDs)"]}]}],"canonical_facts":{"dc:contributor.committeechair":["De La Ree, Jaime"],"dc:contributor.committeemember":["Centeno, Virgilio A.","Phadke, Arun G."],"dc:contributor.department":["Electrical and Computer Engineering"],"dc:creator":["Morton, Daniel David"],"dc:date.accessioned":["2015-05-12T08:00:07Z"],"dc:date.available":["2015-05-12T08:00:07Z"],"dc:date.issued":["2015-05-11"],"dc:description.abstract":["Variable Frequency Drives (VFDs) are utilized in commercial and industrial facilities to improve motor efficiency and provide process flexibility. VFDs are nonlinear loads that inject harmonic currents into the power system, and result in harmonic voltages across the system impedance. This harmonic distortion can negatively impact the performance of other sensitive loads in the system. If a VFD serves a critical function, it may be necessary to supply the VFD from a Diesel Generator or Uninterruptible Power Supply (UPS). These sources have relatively high impedance when compared to a standard utility source, and will result in greater harmonic voltage distortion. This increases the likelihood of equipment failure due to harmonics. The full extent of the impact, however, is typically unknown until an extensive harmonic analysis is performed or the system is installed and tested. This thesis evaluates the impact that source impedance has on the harmonic voltage distortion that is produced by nonlinear loads such as VFDs. An ideal system of varying source types (Utility, Generator and UPS) and varying VFD rectifier technologies (6-Pulse, 12-Pulse and 18-Pulse) is created to perform this analysis and plot the results. The main output of this thesis is a simplified methodology for harmonic analysis that can be implemented when designing a power system with a VFD serving a critical function and a high impedance source like a generator or UPS. Performing this analysis will help to ensure that other sensitive loads will operate properly in the system."],"dc:description.degree":["Master of Science"],"dc:format.medium":["ETD"],"dc:identifier.other":["vt_gsexam:5347"],"dc:identifier.uri":["http://hdl.handle.net/10919/52247"],"dc:publisher":["Virginia Tech"],"dc:rights":["In Copyright"],"dc:rights.uri":["http://rightsstatements.org/vocab/InC/1.0/"],"dc:subject":["Harmonic Analysis","Power Electronics","Variable Frequency Drives"],"dc:title":["Impact of System Impedance on Harmonics Produced by Variable Frequency Drives (VFDs)"],"dc:type":["Thesis"],"thesis:degree_discipline":["Electrical Engineering"],"thesis:degree_level":["masters"],"thesis:degree_name":["Master of Science"],"thesis:institution_name":["Virginia Polytechnic Institute and State University"]},"updated_at":"2026-07-22T22:19:59Z"}