摘要:

The privatisation of the electricity supply industry in the UK and the impending changes in the European market in 1992 represent new challenges to UK power engineers. In addition, there are new markets to be served in the developing world. The resultant problems and opportunities are the theme of the 1990 Hunter Memorial Lecture. The way in which power engineers have tackled changing markets and technology in recent years is described, using a series of examples from a range of equipment. In addition, the need to encourage more people to take up the challenge of engineering as a career is addressed with reference to training and career development, investment in new technology, the development of new products and the need for improved marketing. A further theme is the latest challenge facing the power engineer in the 1990s—the environment. The paper concludes with a description of the construction, by British engineers, of a new 1000 MW coal-fired power station in India, overcoming the challenges of geography, climate and cultural differences in the process.

DOI:10.1049/ip-c.1991.0020

出版商:IEE    

年代:1991

数据来源: IET

摘要:

A new and efficient diakoptical static state estimation algorithm has been proposed. The main objective of developing this algorithm was to obtain an estimator with an improved performance in terms of robustness, accuracy, online CPU time, core memory occupation, intercomputer data transfer, scope for sparsity exploitation, and localisation of bad data effect. In the developed method, a system has been divided into a number of subsystems to take advantage of low dimensionality, sparsity, fast decoupled estimation and parallel processing. The co-ordination among the subsystem level estimators has been done, in each iteration, to improve accuracy of estimates at the cost of little CPU time and nominal data transfer, by the transformation of the tie line flow measurements into voltage drop between subsystems' slack busbar, and the involvement of a small-sized, sparse and constant coefficient matrix with real elements. Saving in CPU time and convergence have also been enhanced by making each iteration of the diakoptical estimator unified, within which no more iterations, either at the subsystem level or at the coordinating level, have been involved. The results of a comprehensive comparative study of the performance of the developed method against the integrated fast decoupled method have also been presented.

DOI:10.1049/ip-c.1991.0021

出版商:IEE    

年代:1991

数据来源: IET

摘要:

A direct method to find the capacitance requirements for a three phase self-excited reluctance generator under any load or speed is introduced. Expressions for the load angle as well as for the minimum value of the excitation capacitance are derived. It has been found that there is a cut off speed, above which no excitation is possible no matter what the terminal capacitance value. Expressions for the value of this speed under open circuit, resistive and pure inductive loads are also derived and presented.

DOI:10.1049/ip-c.1991.0022

出版商:IEE    

年代:1991

数据来源: IET

摘要:

An experimental model is used to represent a generator the solid rotor of which is hunting about synchronous speed. The eddy-current damping factor, and hence the losses in the rotor, are measured at different stages in the construction of two different forms of rotor to assess the effect of the various components such as wedges, end rings and copper damper cage. It is found that a well-connected damper cage is particularly important in improving the damping.

DOI:10.1049/ip-c.1991.0023

出版商:IEE    

年代:1991

数据来源: IET

摘要:

In the paper an efficient noniterative method for ranking line outage contingencies in an AC-DC system based on overload and voltage deviation performance indices is developed. The method is based on the calculation of complex line outage current compensations using a coupled AC-DC load flow Jacobian matrix. The proposed method is further extended for the calculation of line outage distribution factors which could be very useful for reducing the computational burden in security constrained optimisation problems. A mathematical model for handling bus-type switching resulting from reactive power limit violations is also developed. Results for a modified IEEE 14-bus system have been obtained with the proposed method and are compared with those obtained by rigorous AC-DC load flow.

DOI:10.1049/ip-c.1991.0024

出版商:IEE    

年代:1991

数据来源: IET

摘要:

The paper presents a simple and efficient economic dispatch algorithm suitable for unit commitment. It also caters for any combination of polynomial cost functions. The algorithm reduces the economic dispatch into an equivalent lossless problem from which solutions are easily obtained and analytically. The equivalent lossless problem enables the generators whose outputs violate their limit constraints to be handled efficiently and correctly. The algorithm can cater for both theBmatrix and Jacobian matrix loss formulation. Case studies with various test systems are presented and discussed.

DOI:10.1049/ip-c.1991.0025

出版商:IEE    

年代:1991

数据来源: IET

摘要:

The paper presents the result of an extensive study of several typical power systems to explore a fast decoupled load flow (FDLF) model that can exhibit the best convergence property for both well-behaved and ill-conditioned systems. An attempt has been made to examine the relative importance of several parameters, such as line series resistances, shunt reactances and transformer tappings, in the formulation of B′ and B″, on the convergence of the FDLF of Stott and Alsac [1]. Results reveal that a reverse Stott model achieves more or less the best convergence of the FDLF solution, irrespective of whether the systems are well-behaved or ill-conditioned. Amongst the parameters considered in forming [B′] and [B″], the resistance parameter plays the most significant role in the convergence of the FDLF solution, and not the shunts.

DOI:10.1049/ip-c.1991.0026

出版商:IEE    

年代:1991

数据来源: IET

摘要:

The Booth-Baleriaux piecewise-linear method of calculating power system production cost and reliability is extended to include a piecewise-quadratic representation of the equivalent load duration curve. Grid increment size can be chosen without dependence on generator capacities. Twenty or fewer grid increments yield an execution speed and an accuracy that are comparable with the method of cumulants and the mixture of normals approximation. Fifty or more grid increments yield accurate results for expected unserved energy and loss of load probability. The piecewise-quadratic method overcomes limitations inherent in other methods.

DOI:10.1049/ip-c.1991.0027

出版商:IEE    

年代:1991

数据来源: IET

摘要:

The REMMIT (remote magnetic field monitoring instrument transformer) system, a new method for the monitoring and protection of electrical networks, is described. The most significant aspect of this system is that by using remote magnetic field sensors the entire monitoring and protection function is physically and electrically isolated from the network under surveillance and hence cannot contribute to failure modes of that network. The REMMIT system allows both monitoring of a network of currents and realtime detection of fault conditions, where currents fail to flow solely along the defined paths.

DOI:10.1049/ip-c.1991.0028

出版商:IEE    

年代:1991

数据来源: IET

摘要:

A hybrid approach using Monte-Carlo simulation and an enumeration technique for the reliability evaluation of large scale composite generation-transmission systems is presented. The Monte-Carlo method is based on combining the basic random sampling technique with a direct analytical approach for system analysis and the utilisation of a minimisation model for load curtailment. The method presented is suited to the analysis of large systems and can be used to include multi-state representation of generating units. Studies presented illustrate that derating-adjusted two-state models for generating units can lead to pessimistic appraisals of composite system adequacy. Variability in system load can be incorporated by using a chronological load representation or by an aggregated load model. The accuracy of the load representation and the required computation time increases with the utilisation of more steps in the annual load duration curve. The adequacy indices of different composite systems have different sensitivities to the number of steps in the load curve. A procedure for establishing a set of ratios of generation-transmission adequacy indices which can be used to judge the sensitivities of composite system adequacy indices to the number of steps in the load duration curve is presented. It is only necessary in the case of sensitive composite systems to use many steps in the load model to obtain accurate annual indices and fewer steps can provide sufficiently accurate annual indices in the case of non-sensitive composite systems. A non-uniform load increment step model can effectively improve the accuracy of the calculated annual indices for sensitive composite systems. These conclusions are supported by application of the concepts proposed to two test systems.

DOI:10.1049/ip-c.1991.0029

出版商:IEE    

年代:1991

数据来源: IET