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| Abstract: The conventional proportional-integral type control system loops of the current and extinction angle controllers at High Voltage Dc Converter are replaced with Fuzzy Logic based controls. The two approaches are compared using simulations on an electromagnetic transients simulation program. A method to further refine the Fuzzy Logic formulation to yield the most optimum response is presented. The results show that the Fuzzy Logic based approach can provide, at the minimum, a marginal improvement over the P-I based controller. |
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| Abstract: The application of electromagnetic transients simulation in electric power systems was made possible with the initial development of the EMTP program by Dr. Hermann Dommel. EMTP was released for general use in the early 1970's by the Bonneville Power Administration. Utility engineers who applied EMTP to resolving power system problems were rewarded with an exciting new method of analysis. Today, electromagnetic transients simulation is utilized around the world and has become an essential method for studying electric power systems. When users of EMTP attempted to apply early versions of the program to high voltage direct current (HVDC) transmission systems, considerable frustration was experienced. Using the same published algorithm as EMTP, entirely new code was written at Manitoba Hydro to accommodate electromagnetic transients of HVDC converters and controls. Known as EMTDC, this second electromagnetic transients programs, became a useful program for HVDC engineers world wide. As in EMTP, development of EMTDC has continued. Its simulation capabilities also span conventional electromagnetic transients analysis such as examining very complex circuits for overvoltages and insulation coordination, surge arrester studies, current and voltage harmonics and effectiveness of controls and protection equipment. However special emphasis has been placed on swift assembly, simulation and analysis of very large electric power systems which may contain complicated power electronic configurations and associated controls and protection. |
| Abstract: Graphical user interfaces for electromagnetic transients programs are a needed and necessary feature for improved power system study procedures. Experience gained in graphical user interfaces is documented along with improvements which can be made to the electromagnetic transients solution method. The documented developments provide insight into the requirements and operational performance of modern simulation programs. |
| Abstract: Dynamic compensators are often employed at the ac side of HVDC converter connected to weak ac systems to improve stability and to control voltage. This paper presents the transient simulation results of such an application with a mix of static and synchronous compensators at the inverter bus connected to a very weak ac system. An equal mix of static and synchronous compensators offers a better performance in controlling temporary overvoltages than the individual compensators. Interaction between ac and dc systems increases with decreasing ac system strength. This is illustrated by comparing the results of simulations conducted on an ac/dc system having varying ac system strength. |
