THE UTILIZATION OF NEW TECHNOLOGIES IN GENERATION AND TRANSMISSION TO ATTEND THE NEEDS OF PRESENT AND FUTURE ELECTRICAL POWER SYSTEMS

摘要

In the present article are presented and discussed thernrecent and new improvements in generation andrntransmission systems, in order to cope with the changesrnin the traditional structure of the electricity sector, longrnbased on vertical integration, to a new unbundledrnstructure with a wide range of new market participants.rnThese changes are leading to an increase in therntransmission lines power flows, sometimes pushing therngrid to its physical limits. This power increasernthroughout the system has to be attended by thernconstruction of new power plants, transmission linesrnand by new equipments.rnDue to the deregulation and reformation of thernelectricity sector, to give an example, it has beenrnobserved an increase in the interconnection power flowrnbetween the Scandinavian system (Nordel) and the westrnEuropean system (UCPTE), which has doubled in thern1993-1998 period and by the projections made isrnexpected to double again up to 2002.rnThese structural changes have brought the electricityrnsector to a critical period of transition. In the mediumlongrnterm, competition is expected to unleash dramaticrntechnological innovations. In the short term, however,rnpower grids are being put to new uses for which theyrnwere not originally designed.rnAt the generation side researches are being done inrnsuperconducting generators and more efficientrnrenewable generators which may be placed distributedrnallover the system and have the potential to reducerntransmission/distribution reinforcements and systemrncosts. Variable speed generators are also discussed asrnits participation in the energy market may grow as itrnmay produce more energy with less water, if its turbinernoperates at its maximum efficiency.rnFinally, it is presented the Superconducting MagneticrnEnergy Storage Systems, as it may be used, in thernfuture, as the main energy storage source and for itsrnability to handle transient conditions. These generatingrnsources may be an alternative to the energy suplly inrnthe future, complementing the conventional thermal,rnnuclear and hydraulic generations.rnAt the transmission side, due to the restrictions forrnconstruction new transmission lines, recent and newrntechnologies for maximizing the utilization of existentrnand future systems, including the power flow controlrnthroughout the system by a new generation ofrnequipments based on power electronics, are presented,rnin order to avoid or postpone the construction of newrnlines and equipments, as well as to enhance the steadyrnstate and transient/dynamic performance of powerrntransmission systems. The following technologies arerndiscussed: Direct Current Transmission with VoltagernSource Converters using IGBT Semiconductors;rnSuperconducting Cables; Gas Insulated UndergroundrnCables; Compact and High Surge Impedance LoadingrnLines and Flexible AC Transmission Systems (FACTS).rnThis article aims at contributing for a better knowledgernand understanding of the recent and new technologies inrngeneration and transmission, in order to improve thernsteady state and transient/dynamic performance ofrnpresent and future electrical power systems.