097 Practical considerations in the load models for load management

097 Practical considerations in the load models for load management

Abstracts method, active set and quadratic penalty function, is presented in this paper. This approach is of robust and accurate convergent characteri...

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Abstracts method, active set and quadratic penalty function, is presented in this paper. This approach is of robust and accurate convergent characteristic. The computation time is directly proportional to network size, and the initial points do not affect the solved optimal result. The program package using this method has been extensively used in China since 1985, and the operational experiences are satisfactory. Some of the optimal numerical results are presented. Other aspects of the program and some calculation results are also addressed.

095 Aspects of Relational Database Management and Human Computer Interface Required for a Fully Integrated load Forecasting System M. R. Irving, R. Thuriby, pp 263-268 Algorithms for forecasting the future load on an electricity distribution or transmission network are now well established. This paper concentrates on the other aspects of an integrated load-forecasting system: database management, human-computer interface, and interworking with other computer systems. The use of objectoriented design techniques and relational database technology is presented as an efficient means to meet user requirements. The Windows-Icons-Menus-Pointers philosophy provides a suitable human computer interface. The need for the system to obtain information from external sources and to provide forecasts to other systems has had a major influence on the design of the system. Finally, some topics of further research are presented.

096 Modelling the Temperature Factor In Short-Term Electrical Load Forecasting Ilkka Karanta, Kukka Ruusunen, pp 269-272 The effect of outdoor temperature in short-term (from a few hours to a few days) electrical load is discussed. The quality of outdoor temperature as input is examined by its order of persistent excitation. This causes restrictions on what kind of model may be used. A class of models that are nonlinear with respect to outdoor temperatures is suggested as an alternative to linear models in short-term electrical load forecasting. 097 Practical Considerations in the Load Models for Load Management

A. Gabaid6n, C. Alvarez, R.P. Malham~, pp 273-279 The problem of the coefficients dispersion in the elemental loads forming a control group of a load management application in real distribution systems is approached in this paper. A model, based on the physically based loadmodelling approach is proposed for the study of the effect of this dispersion on the real behaviour of the control groups or on the quality of the control action. A real-life test area is analyzed in order to show the importance of the problem and to draw practical conclusions.

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switch in the system is evaluated and a ranked list is generated. A previous topological process allows some additional reduction in the computing time. The method is suitable for both operational and planning purposes.

099 Distribution Networks Loss Reduction: Capacitor Allocation and Operation C. Alvarez, R. Molina, pp 287-292 The importance of optimum planning and operation of shunt capacitors in primary distribution feeders is increasing in many countries because of the growing regulation of the electric energy supply quality and efficiency. A discrete way to solve this problem is desirable in order to account for real-life situations. An efficient method based on the use of dynamic programming is proposed in this paper. Results proving its suitability to solve the problem are shown.

100 LOw Order Dynamic Controllers for HVDC Links Supplying Weak Systems G. J. Georgantzis, G. B. Giannakopoulos, N. A. Vovos, pp 293-298 The design process of centralized suboptimal low-order dynamic controllers for HVDC links supplying weak AC power systems, using the projective control technique, is presented. The controllers are simple and easily superimposed to the classical control system of the HVDC links. They exploit the possibility of simultaneous control of active and reactive power at the inverter side, in order to achieve a very effective frequency and voltage control for the supplied AC system. The response of the proposed controllers has been tested under large load disturbances on a realistic electrical power system using a fundamental frequency digital simulation program.

101 Harmonic Interference of HVDC in Transmission Systems G. Brauner, G. Moraw, pp 299-304 The HVDC-Iink in Dtlrmohr (Austria) now has nine years of operational experience as the first interconnection between the western and eastern transmission systems in Europe. At the moment two further HVDC-links are under erection, one in south-east Austria and the other in Germany. The influence of the existing HVDC-Iink on the harmonic distribution in the transmission network and the subordinated distribution level has been investigated. On the basis of advanced measurements and simulations, the modelling accuracy could be conftrmed and the influence of a second HVDC link in Austria evaluated.

102 HVDC-Transmission Line Model for Transient Simulation Purposes

098 Reconflguration for Loss Reduction in Distribution Networks Carlos Rold~in, Nicolas Gonzalez, Carlos Alvarez,

pp 281-286 The automation of the distribution level offers new possibilities for more-efficient and -reliable operation of a distribution system. The problem approached in this paper is that of network re.configuration for resistive loss reduction. The proposed method is based on an AC power flow performed over the completely meshed distribution network. A fast algorithm uses the compensation theorem and takes advantage of the similarities between radial and weakly meshed networks. The effect of opening every

Rina Navarro-Adlemo, Claes Breitholtz, pp 305-310 A lumped bipolar HVDC-transmission-line model, based on least squares fitting of orthogonal polynomials, which are space-dependent, and have time-dependent coefficients, is presented and examined in this paper. The model enables the line voltage and current to be approximately determined for arbitrary points along the line e.ad at arbitrary times. The model is not restricted to lossless lines or to the steady state. Further, an example is given showing how the transmission line model is extended to include arbitrary linear terminal dynamics, It is also demonstrated that the model is useful as a simulation tool.