摘要:

The paper describes a new method developed for solving the thermal unit commitment problem in large-scale electrical power systems semi-rigorously, by using a hybrid form of the discrete decision linear programming (DDLP) [13] and heuristic techniques. It is capable of incorporating all the operational constraints of the system and obtaining fully feasible schedules. The developed algorithm has been tested on a CDC7600 computer to solve the thermal unit commitment problem in the South-Western Region subsystem of the CEGB. Simulation results have shown that various solutions with different characteristics can be obtained for the same problem, requiring modest computer time and memory. Encouraging financial savings have also been obtained due to employing an optimisation (DDLP) technique within the method.

DOI:10.1049/ip-c.1986.0028

出版商:IEE    

年代:1986

数据来源: IET

摘要:

A new method is proposed to develop dynamic equivalents of coherent machines represented by detailed models. The method estimates the parameters of an equivalent synchronous machine and an equivalent excitation system using a noniterative procedure. The equivalent parameters are determined by structure preservation of the coefficient matrices in a time-domain representation of the machines. The development of dynamic equivalents by the reported procedure requires much less computation time than the existing frequency-domain procedure. The derived equivalent can be used with conventional transient stability programs without any modification. Validation test of the proposed equivalencing procedure on a 50 machine power system is reported in the paper.

DOI:10.1049/ip-c.1986.0029

出版商:IEE    

年代:1986

数据来源: IET

摘要:

The application of an adaptive pole-shifting self-tuning power system stabiliser (SPSS) to a mulit-machine power system is described. Results presented in the paper show that this adaptive stabiliser performs better than a conventional unit. It is easy to implement because only the locally available measurements are used. Studies also show that there is no conflict between the proposed SPSS and other kinds of power system stabilisers on the system.

DOI:10.1049/ip-c.1986.0030

出版商:IEE    

年代:1986

数据来源: IET

摘要:

Single-pole-autoreclosure(SPAR) application demands reliable phase selection. The need to minimise the likelihood of single-phase faults spreading to other phases and a generally increasing requirement for reduced circuit dead-times, increasingly demands that phase-selection be accomplished in a time compatible with ultra-high-speed (UHS) fault clearance. The paper outlines the principles of operation and design of a new UHS digital phase-selector which, by viuture of employing specially filtered versions of the superimposed voltages and currents, is immune to problems of indiscrimination caused by load current. The paper concludes with a consideration of the performance of the new phase-selector in typical 500 kV transmission applications employing SPAR.

DOI:10.1049/ip-c.1986.0032

出版商:IEE    

年代:1986

数据来源: IET

摘要:

Power systems are subjected to many forms of transient phenomena brought about essentially by sudden changes in the steady state values of voltages or currents. Such changes may be the result of a lightning stroke, some malfunction of the system or be brought about by the switching of a circuit either to clear a fault or as a normal operational procedure. To be practical the scope of the review has had to be restricted. Nevertheless it has been found possible to cover a wide range of transient voltages from those which pose problems in transmission systems operating at the highest levels of system voltage down to those which can appear in the domestic situation. Apart from mentioning nonlinear elements in systems, the review is, in the main, restricted to phenomena which are essentially linear in nature and no attempt has been made to include the more complicated phenomena associated with ferroresonance or the production and propagation of harmonic voltages and currents. The review does not claim to be exhaustive but it is hoped that the major causes of transient overvoltages have been considered. In addition to dealing with the causes of transient overvoltages, the review indicates the range of analytical methods that are now available for their analysis and assessment.

DOI:10.1049/ip-c.1986.0033

出版商:IEE    

年代:1986

数据来源: IET