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00506 Power electronics in HVDC power transmission
06 Modollng end ?? lmuletlon of trenemleelon eyetem %I00494 ?? hleld wlree under unbalanced condltlone 2~2~~ T. N. et al., Electric Power Systems Res., Sep. 1994, 30, (3), * The purpose of this investigation is to calculate the ground return current under steady-state or transient conditions, given the phase currents in the conductors of two unbalanced three-phase parallel circuits. Thus, the shield wires can be modellcd to carry appropriate current depending upon the currents in the three hase conductors. For example? when a fault occurs on a phase conductor, tRc currents that start flowing m the phase conductors may become unbalanced. Under such conditions, the currents that are coupled into the shield wires will be more important.
Modeling of a Ier e electric power system for optl%I00495 mal control of dynemlc etebllPty Bilir, B. et al., Electric Power Systems Res., Sep. 1994, 30, (3), 191-196. The paper describes a general state-variable fo& of mathematical modellinn which mav be used to control the dvnamic stabilitv of a larger newer system optimally. Based on the linear&ion about the operating point of the system, a complete model for dynamic stability control is obtained by combining transmission network equations, full-order synchronous machine equations, the exciter and voltage regulator model, torque equations, and the governor-hydraulic model in a matrix form which includes supplementary excitation and governor control signals. The complete model may then be simplified as a low-order model by ne letting the governor effects, exciter time constant, and all but the field a ux linkage variations of the machines in order to reduce computational requirements.
Electric power generation
%/00591 eyeteme
Modelllng of SVC for ?? teblllty evaluation uelng ?? tructure preeervlng energy function Padiyar, K.‘R. and Im&nuel;~. Electrical Power & Energy Systems, 1994, 16, (5), 339-348. In this paper the static var compensator (SVC) has been accurately incorporated into the structure preserving energy function (SPEF) with a detailed generator model including flux decay and transient saliency, automatic voltage regulator (AVR) and damper winding. The SVC can be modelled for transient stability studies using the steady-state control characteristic and is treated as a voltage-dependent reactive power load. This simplifies simulation and results in the derivation of an exact path-independent energy function to account for the effect of the SVC inclusive of its limits. Application of the SPEF to transient stability evaluation is illustrated with a numerical example including the critical case of a three-phase fault with line outage. 95/00497
95/00495
Monitoring turbine efflclency et Sloy Modern Power Systems, Oct. 1994, 14, (lo), p. 70. Reports that Development Engineering International, the condition monitonng specialist corn any based in Aberdeen, Scotland, is commissioning a monitormg system Por the main generating turbines at Hydro-Electric’s Sloy power station, on the banks of Loch Lomond in Scotland.
Neural network breed transient eteblllty eeeaee95lOO499 ment of electric power eyeteme h$y;12 D. R. ef al., Electric Power Systems Rex, Sep. 1994, 30, (3), In this paper a systematic procedure to design an intelligent neurocontroller to assess the dynamic security of interconnected power systems is presented. This ap roach focuses on the integration of modern control theory together wi 1 the adaptive networks to determine critical clearing time for power systems.
On the mexlmum efficiency of tranemleelon Ilnee: ~2Yoo Pauazoalou, T. M.
Electrical Power & Energy __-Systems. 1994. 16, (51, . ,.
349-35r. The results of the first paper on the maximum efficiency of transmission lines are summarized in a theorem. The line load under the condition of maximum transmission efficiency, is expressed analytically, computed for cases of practical interest and compared with the St Clair loadability curves. The theory of maximum transmission efficiency is extended to the important case of interconnected lines. Examples are given to illustrate the results.
On-line eteedy-etete eecurlty eeeeeement of power
T;yf3t S. et al., Elecbic Power Systems Res., Jul.-Aug. 1994, 30, (2), . Steady-state security assessment primarily addresses the question of the adequacy of generating and transmission capacity to meet load demand. In security assessment, there are two aspects of system failure that should be considered, namely, load curtailment and system collapse. The study of steady-state security has become essential, specially in modem large interconnected power systems. In this paper, a comprehensive conceptual framework and technique for on-line steady-state security assessment is suggested.
95/oo5o2 Optlmel clueterlng of power networks uelng aenetlc elaorlthme -. Dmg, H. et-al., Electric Power Systems Res., Sep. 1994, 30, (3), 209-214. The aper presents a new method for optimal network decomposition base B on genetic algorithms (GAS). GAs present a powerful, globally oriented optimization method which ex loits the mechanism of natural genetits, working on population of can I$Idate solutions in an effort to reach optima or near optima. Test results on IEEE standard networks are given and compared with those using simulated annealing. The genetic algorithm approach is found to produce significantly better solutions.
95lQ%03 Modeling of ?? eturetlon In lnductlon machlnee 95/004% ueing EMTP, PSplce end a dedicated computer program Reynaud, J. F. and Pillay, P. Electric Power Sysrems Rex, Sep. 1994,30, (3), 279-285. The effects of saturation in an induction motor’s performance during a direct on-line start are studied using three different techniques.
and utilisation (scientific, technical)
Optlmal fault locatlon for trenemleelon eyeteme
Novosel, D. et al., ABE Review, 1994, (8), 20-27. Microprocessor-based fault locators from ABB are being used by transmission hne operators in more than 40 countries around the world. Recently, several neti options allowing more accurate fault location have been examined. They include algorithms which use the information from one substation only-as well as algorithms which make use of information communicated by the substations at both ends of the line. The algorithm which is best suited for an application will de end on the existing communications facilities and on the availability oP the required data. The new oneterminal and two-terminal data algorithms have been successfully tested.
95lQO504 Optlmel moduletlon controller for ?? uparconductlng magnetic energy storage Machowski, J. and Nelles, D. Electrical Power & Energy Systems, 1994, 16, (5), 291-300.
A study of power system transient stability enhancement through effective use of the sunerconductinn magnetic enerav storage is nresented. Simultaneous o timai modulationof th: active anTreact& poGer is formulated as a modu P. ation which forces the fastest dissipation of energy released in the system by a given fault. For this definition the optimal modulation strategy has been derived from the direct Lyaounov method for a multi-machine nonlinear power system model. This-thiorctical optimal strategy can easily be technically realized as a nonlinear control using only locally measureable quantities. The validity and robustness of the proposed local control has been confirmed by simulation tests.
95/00505 Optimum dletrlbutlon eyetem hermonlc filter deelgn uelng a genetlc elgorlthm Yang, H. and Richards, G. G. Electric Power Systems Res., Sep. 1994, 30, (3), 263-267. The paper presents a technique for the anticipation of harmonic distortion as well as selection and placement of filters on distributin systems which have multiple harmonic sources and constantly changing characteristics caused by- compensating capacitor switching and load impendance changes. The purpose is to predict and reduce harmonic voltage distortion for all buses in the system to comply with IEEE Standard 510. A genetic algorithm is used in this technique and shows itself an effective tool in optimizing a multivariable objective function.
95lQo595 Power electronics In HVDC power tranemleelon Brough, C. A. er al., Power Engg. J., Oct. 1994, 8, (5), 233-240. Describes the function and the hardware of a typical scheme for highvoltage direct current power transmission. Its basis is a 2 X 500MW backto-back scheme to interconnect the Western and Southern power regions of India. This technology permits sophisticated and rapid control of power system quantities-power, reactive ower, fre uency and voltage-by adjusting the timing of thyristor valve H. mng in re9 ation to AC system voltage. The latest high-voltage thyristor and convertor control equipment is described.
Fuel end Energy Abetrecte January 1995
29
Modeling of a Ier e electric power system for optl%I00495 mal control of dynemlc etebllPty Bilir, B. et al., Electric Power Systems Res., Sep. 1994, 30, (3), 191-196. The paper describes a general state-variable fo& of mathematical modellinn which mav be used to control the dvnamic stabilitv of a larger newer system optimally. Based on the linear&ion about the operating point of the system, a complete model for dynamic stability control is obtained by combining transmission network equations, full-order synchronous machine equations, the exciter and voltage regulator model, torque equations, and the governor-hydraulic model in a matrix form which includes supplementary excitation and governor control signals. The complete model may then be simplified as a low-order model by ne letting the governor effects, exciter time constant, and all but the field a ux linkage variations of the machines in order to reduce computational requirements.
Electric power generation
%/00591 eyeteme
Modelllng of SVC for ?? teblllty evaluation uelng ?? tructure preeervlng energy function Padiyar, K.‘R. and Im&nuel;~. Electrical Power & Energy Systems, 1994, 16, (5), 339-348. In this paper the static var compensator (SVC) has been accurately incorporated into the structure preserving energy function (SPEF) with a detailed generator model including flux decay and transient saliency, automatic voltage regulator (AVR) and damper winding. The SVC can be modelled for transient stability studies using the steady-state control characteristic and is treated as a voltage-dependent reactive power load. This simplifies simulation and results in the derivation of an exact path-independent energy function to account for the effect of the SVC inclusive of its limits. Application of the SPEF to transient stability evaluation is illustrated with a numerical example including the critical case of a three-phase fault with line outage. 95/00497
95/00495
Monitoring turbine efflclency et Sloy Modern Power Systems, Oct. 1994, 14, (lo), p. 70. Reports that Development Engineering International, the condition monitonng specialist corn any based in Aberdeen, Scotland, is commissioning a monitormg system Por the main generating turbines at Hydro-Electric’s Sloy power station, on the banks of Loch Lomond in Scotland.
Neural network breed transient eteblllty eeeaee95lOO499 ment of electric power eyeteme h$y;12 D. R. ef al., Electric Power Systems Rex, Sep. 1994, 30, (3), In this paper a systematic procedure to design an intelligent neurocontroller to assess the dynamic security of interconnected power systems is presented. This ap roach focuses on the integration of modern control theory together wi 1 the adaptive networks to determine critical clearing time for power systems.
On the mexlmum efficiency of tranemleelon Ilnee: ~2Yoo Pauazoalou, T. M.
Electrical Power & Energy __-Systems. 1994. 16, (51, . ,.
349-35r. The results of the first paper on the maximum efficiency of transmission lines are summarized in a theorem. The line load under the condition of maximum transmission efficiency, is expressed analytically, computed for cases of practical interest and compared with the St Clair loadability curves. The theory of maximum transmission efficiency is extended to the important case of interconnected lines. Examples are given to illustrate the results.
On-line eteedy-etete eecurlty eeeeeement of power
T;yf3t S. et al., Elecbic Power Systems Res., Jul.-Aug. 1994, 30, (2), . Steady-state security assessment primarily addresses the question of the adequacy of generating and transmission capacity to meet load demand. In security assessment, there are two aspects of system failure that should be considered, namely, load curtailment and system collapse. The study of steady-state security has become essential, specially in modem large interconnected power systems. In this paper, a comprehensive conceptual framework and technique for on-line steady-state security assessment is suggested.
95/oo5o2 Optlmel clueterlng of power networks uelng aenetlc elaorlthme -. Dmg, H. et-al., Electric Power Systems Res., Sep. 1994, 30, (3), 209-214. The aper presents a new method for optimal network decomposition base B on genetic algorithms (GAS). GAs present a powerful, globally oriented optimization method which ex loits the mechanism of natural genetits, working on population of can I$Idate solutions in an effort to reach optima or near optima. Test results on IEEE standard networks are given and compared with those using simulated annealing. The genetic algorithm approach is found to produce significantly better solutions.
95lQ%03 Modeling of ?? eturetlon In lnductlon machlnee 95/004% ueing EMTP, PSplce end a dedicated computer program Reynaud, J. F. and Pillay, P. Electric Power Sysrems Rex, Sep. 1994,30, (3), 279-285. The effects of saturation in an induction motor’s performance during a direct on-line start are studied using three different techniques.
and utilisation (scientific, technical)
Optlmal fault locatlon for trenemleelon eyeteme
Novosel, D. et al., ABE Review, 1994, (8), 20-27. Microprocessor-based fault locators from ABB are being used by transmission hne operators in more than 40 countries around the world. Recently, several neti options allowing more accurate fault location have been examined. They include algorithms which use the information from one substation only-as well as algorithms which make use of information communicated by the substations at both ends of the line. The algorithm which is best suited for an application will de end on the existing communications facilities and on the availability oP the required data. The new oneterminal and two-terminal data algorithms have been successfully tested.
95lQO504 Optlmel moduletlon controller for ?? uparconductlng magnetic energy storage Machowski, J. and Nelles, D. Electrical Power & Energy Systems, 1994, 16, (5), 291-300.
A study of power system transient stability enhancement through effective use of the sunerconductinn magnetic enerav storage is nresented. Simultaneous o timai modulationof th: active anTreact& poGer is formulated as a modu P. ation which forces the fastest dissipation of energy released in the system by a given fault. For this definition the optimal modulation strategy has been derived from the direct Lyaounov method for a multi-machine nonlinear power system model. This-thiorctical optimal strategy can easily be technically realized as a nonlinear control using only locally measureable quantities. The validity and robustness of the proposed local control has been confirmed by simulation tests.
95/00505 Optimum dletrlbutlon eyetem hermonlc filter deelgn uelng a genetlc elgorlthm Yang, H. and Richards, G. G. Electric Power Systems Res., Sep. 1994, 30, (3), 263-267. The paper presents a technique for the anticipation of harmonic distortion as well as selection and placement of filters on distributin systems which have multiple harmonic sources and constantly changing characteristics caused by- compensating capacitor switching and load impendance changes. The purpose is to predict and reduce harmonic voltage distortion for all buses in the system to comply with IEEE Standard 510. A genetic algorithm is used in this technique and shows itself an effective tool in optimizing a multivariable objective function.
95lQo595 Power electronics In HVDC power tranemleelon Brough, C. A. er al., Power Engg. J., Oct. 1994, 8, (5), 233-240. Describes the function and the hardware of a typical scheme for highvoltage direct current power transmission. Its basis is a 2 X 500MW backto-back scheme to interconnect the Western and Southern power regions of India. This technology permits sophisticated and rapid control of power system quantities-power, reactive ower, fre uency and voltage-by adjusting the timing of thyristor valve H. mng in re9 ation to AC system voltage. The latest high-voltage thyristor and convertor control equipment is described.
Fuel end Energy Abetrecte January 1995
29