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PANEL DISCUSSION P5 Impact of Distributed Generation on Harmonics and Power Quality Chair: Siri Varadan, Nexant, Inc. Panelists: Elham Makram, Clemson University Thomas Baldwin, Florida State University Mark McGranaghan, Electrotec Concepts Presentation Topics and Order
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PANEL DISCUSSION P5Impact of Distributed Generation on Harmonics and Power QualityChair: Siri Varadan, Nexant, Inc.Panelists:Elham Makram,Clemson UniversityThomas Baldwin,Florida State UniversityMark McGranaghan,Electrotec Concepts
Presentation Topics and Order • Effect of Harmonics on Distributed Generation – • Elham Makram • Harmonic and Distributed Generation Interaction Issues in the U.S. Navy All-Electric Ship Program – • Tom Baldwin • PQ Issues for DG Applications – • Mark Mc Granahan • Software Aspects of PQ in a DG Context – • Siri Varadan • General Discussion
‘Independent’ Modules to Ensure Vendor-Independence in Utility-wide PQ Monitoring Systems by Mehmet Kemal Celik
Overview of the Presentation • Introduction • Modular System Design • Benefits • Functional Design • A Customized Analysis Example • Conclusions
Power Quality Monitoring Systems • Integrated systems of several PQ monitors are being set up • increasing number of monitors • emerging computer technologies on hardware and software area • different architectures that serve all PQ monitors with a single large database • client-server • Intranet/Internet
Power Quality Monitoring Systems • Such integrated designs have several advantages • efficient and fast analysis of large volumes of data • establish centralized PQ data • usage of standard PQ indices within the utility • standardization of customer complaint evaluation • modular, expendable and portable system design • reduction in system maintenance and expansion costs • standard data analysis tools on LAN/WAN, Intranet, etc. • centralized security system
Main PQ Monitoring System Components • Communication System - physical media (fibre optics, copper, wireless, etc), modems (DSL, telephone, etc.), Ethernet network components (switches, routers, etc), etc. • Information Technology (IT) System - computers (data servers, polling stations, client stations, etc), system software (operating system, etc), database system, protocol converters, user applications (GUI, analytical applications, alarm and information dispersal software, web publishing, etc.), etc. • Monitoring System - instrumentation (PQ monitors, RTUs, sensors, etc), data retrieval and configuration software, etc
PQ Monitoring System Components Monitoring system Polling server Database/Application server ODBC database IT system Communication system WAN End users PQ Monitors
Implementation Benefits • Removes vendor dependencies - The best alternatives, specific to meet all of the utility’s requirements, are used • Easy implementation of analysis applications • Analytical applications can be written that use the ‘standardized databases • Industry standard and vendor independent applications, each best suited to meet utility’s requirements • Ease in implementation of web reporting applications - Latest web hosting and interactive site technologies can be used. • Economic benefits - With several alternative systems, price of the individual modules is more competitive
Operational Benefits • Maintenance of a standard database • Allows cheap and regular maintenance. Facilitates easy database expansion. Single database ensures that there is no duplication of data from all current and potential future power quality monitors. • Existing trained personnel can quickly come up to speed with the operation & maintenance of the system - No new elaborate training is necessary
Future Expansion Benefits • Future subsystem components can be selected solely on their merit - ‘Vendor-independence’ • Modular design allows • utilization of future advances in instrumentation, communication, and software technologies • utilization of upgrading without a major investment in a complete system overhaul
Conceptual Design • Future expandability; plug-and-play concept Instrumentation Database Required software - Communication - Data logging - Configuration Meter server Database server LAN End user Fiber Optics and DSL modems Leased Lines or other media Current PQ meters Future PQ meters
F 3 component analysis Data from Harmonic Communication server analysis Web reporting ‘Basic’ software is installed on the ODBC Communication server Application database server Event reporting PQ characterization Independent software modules, each of which Import/Export of data can be modified/upgraded to other formats independently ( PQDIF , COMTRADE , etc) Software Modules
Data Analysis and Reporting • Calculation Modules • RMS, Root Mean Square, (voltage or current) • SARFI • Fundamental voltages and currents of Fourier series • Total voltage harmonic RMS, etc. • Expert system rules constitute a simple if-and-then logic for combining windowed time data with relational and topological data • Extract module basically extracts the required portion of the data from database tables • Display is in the form of graphs, tables and text
Typical Customization – Disturbance Aggregation • Monitors track individual PQ disturbances • A deviation on a single phase at a single instant in time will be recorded as a disturbance • An electrical system event may cause multiple disturbances • For example, a single event: a tree branch blowing against a 12kV line • It can result in voltage sags on more than one phase • Sags will be recorded at PQ monitors located at different parts of feeder with small time lags • Arcing may generate wave shape faults as well • Furthermore, fault current may result in a series of momentary outages, maybe followed by an interruption to service • PQ monitoring should be able to relate all disturbances to the actual cause (event)
Disturbance Aggregation • Two sets of disturbances, one on feeder 1, and another on feeder 2 • voltage sag at t = 1 from PQ monitor 2 on feeder 1 • Voltage sag from PQ monitor 1 at t = 2 on feeder 1 • Voltage sag from PQ monitor 3 at t = 2.5 on feeder 1 • Momentary outage from PQ monitor 2 at t = 3.5 on feeder 1 • Voltage sag from PQ monitor 4 at t = 3.6 on feeder 2 • Voltage sag from PQ monitor 5 at t = 4 on feeder 2 • Waveform distortion from PQ monitor 6 at t = 4.5 on feeder 2
Disturbance Aggregation • Sequence of disturbances • all due to a tree branch blowing against a line on feeder 1 • Or, the disturbances on feeder 2 may be due to an independent event on feeder 2, such as lightning
Disturbance Aggregation • A properly sized moving time window that starts with the first event of the sequence will capture most of the practical situations, such as • event data that are from different phases on the same monitor • that are far apart from each other only by infinitesimal time intervals, etc.
Disturbance Aggregation However, fixed size moving time windowing may cause inaccurate aggregation of events if it is not properly sized and used as the only decision criteria
Disturbance Aggregation If relational information is used with adaptive window sizing, accuracy and robustness is enhanced
Disturbance Aggregation • In actual implementation, many more variables are considered, such as • severity of the events • sequence with respect to the location • relational information and connectivity • electrical and geographical distance • types of substation and feeder equipment used • protection schemes utilized, etc.
Conclusions • Modular – system components can be changed without major modifications • Expandable – new monitoring systems can be added without a complete system overhaul • Easier to maintain • Standard unified set of tools across the users • Customizable applications