摘要:

An expert system approach to solve the problem of generation expansion planning is presented. The approach is based on the decision tree technique which is used instead of the currently used techniques of mathematical programming. The expert system approach is capable of emulating human expertise in the field of generation planning. New concepts based on the natural properties of the problem are developed to minimise the computation burden by making in the minimum size. The solution technique satisfies the current objectives of strategic planning and is capable of modelling the various uncertainties inherent in the problem of generation expansion planning.

DOI:10.1049/ip-c.1988.0036

出版商:IEE    

年代:1988

数据来源: IET

摘要:

A wind-turbine driven self-excited induction generator is considered as a variable speed, constant voltage, constant frequency supply for isolated resistive loads. First, a general nonlinear model of the system is developed in a synchronously rotating reference frame. Next, using a modified approach of the singular perturbation theory, an order reduction is carried out by neglecting the fast transients existing in the system and a simplified model is obtained. Then, based on the reduced order model, the steady-state operating characteristics and the stability performance of the system are derived. Finally, the simplified model is used to develop a control strategy which aims to maintain the generator terminal voltage and frequency constant in case of variations in the load and/or windspeed.

DOI:10.1049/ip-c.1988.0037

出版商:IEE    

年代:1988

数据来源: IET

摘要:

The paper, which employs damping torque concepts associated with frequency response analysis, considers the co-ordinated design of power system stabilisers (PSSs) in multimachine power systems. It endeavours to extend to the multimachine environment some of the earlier work which was applied to the analysis of the single machine case, and which provided an insight into the action of the stabiliser. The aim of the proposed approach is to provide, through the action of the stabiliser, an electrical damping torque proportional to speed perturbations, i.e. ΔPei(s) =DiΔωi(s). The stabiliser network is designed to compensate for the phase lag and gain in the machine/system transfer function ΔPei(s)/Δvri(s). The stabiliser gainDiis coordinated, in the first instance, so that the damping effect is distributed among those machines fitted with stabilisers in proportion to their ratings. The damping performance of a sample power system with PSSs installed is shown to be comparable to that for a multimachine system without PSSs in which a pure damping torque is introduced artificially in the transfer function block representing shaft dynamics. Owing to machine interaction, however, an additional left shift of certain oscillatory modes is shown to be due to an electrical damping torque introduced on machineithrough the action of the PSS on machinej.

DOI:10.1049/ip-c.1988.0038

出版商:IEE    

年代:1988

数据来源: IET

摘要:

The paper considers real-time simulation over the operational timescales in an electrical power system and presents a mathematical technique for the decomposition of a set of nonlinear algebraic and differential equations, which result from the corresponding dynamic model. It is shown that the resulting algorithm is suitable for implementation on parallel processors with a 32-bit word capability. The results illustrate that the proposed decomposition technique results in a significant saving in simulation elapsed time, and can consequently be applied to the real-time simulation of large power systems, using relatively inexpensive microprocessor-based hardware.

DOI:10.1049/ip-c.1988.0039

出版商:IEE    

年代:1988

数据来源: IET

摘要:

A new method for the design of static WLS state-estimators on large-scale power systems is described. The approach is based on a simple partitioning, termed ‘α-decomposition’ of the measurement model, and the estimator is implemented on two levels within a multipleprocessor environment. The lower level computation, executed within subsystem processors operating in parallel, is noniterative and of reduced order; the upper level algorithm, also noniterative and of low order, is executed in a single processor. The solution is obtained from alternate entries to the lower and upper levels, continued to a convergence. Necessary and sufficient conditions for convergence are derived, and lead to new definitions for observability on decomposed power systems. Tests for ‘α-observability’ may be distributed amongst the processors on two levels. The method is optimal and structurally efficient, and convergence is fast (theoretically quadratic). The structure of the estimator is simple and well-defined, and possibilities for suboptimal variants are suggested.

DOI:10.1049/ip-c.1988.0040

出版商:IEE    

年代:1988

数据来源: IET

摘要:

The paper forms Part 1 of a two-part series which tests the performance of several techniques for two-level state estimation. The main purpose is to develop an efficient and fast algorithm for a large power system. Part 1 gives the analytical formulation of six algorithms of the two-level state estimator

DOI:10.1049/ip-c.1988.0041

出版商:IEE    

年代:1988

数据来源: IET

摘要:

The paper is the second of a two-part series. The aim of Part 2 is to establish an algorithm which has a consistent convergence property and is also able to handle bad data in the subsystem, as well as in the interconnection area. Part 2 therefore deals mainly with the computational experience of the integrated state estimation (ISE) and six algorithms of the TLSE which were formulated in Part 1 of the series.

DOI:10.1049/ip-c.1988.0043

出版商:IEE    

年代:1988

数据来源: IET

摘要:

The paper presents a new approach for planning high voltage transmission networks. The developed simulation model takes into account the capital investment cost in its discrete form as well as the cost of transmission losses. The constraint equations include the DC load flow equations and line loading constraints. The voltage loop equations are written in a modified form, such that a closed-loop equation will be ineffective if any line of this loop is deleted. The simulation model utilises the mixed-integer linear programming technique to obtain the least-cost network satisfying line loading constraints. Verification of the method is made through a test example.

DOI:10.1049/ip-c.1988.0044

出版商:IEE    

年代:1988

数据来源: IET

摘要:

According to a previous study, the induced voltage due to any current shape in the lightning channel can be obtained through the application of the Duhamel integral to the induced voltage due to a step current in the lightning channel. The paper presents an alternative expression for the Chowduri–Gross model, using a method different from that previously employed. This expression gives the induced voltage directly in terms of the inducing voltage due to a step current. The simplicity of the expression is particularly evident when calculating the induced voltage due to a ramp current. The expression for this induced voltage is used to obtain induced voltage pulse shapes due to a current with a linearly-rising front. Good agreement is obtained with a previously published plot.

DOI:10.1049/ip-c.1988.0045

出版商:IEE    

年代:1988

数据来源: IET

摘要:

The paper deals with the problems which arise in the contacts of power switches at LV distribution systems, especially in cases where emergency loads cannot allow programmed power interrupts through the central distribution panels to perform maintenance. Dust and other local impurities accumulated on the metal surfaces deteriorate the contacts with the time and the switch's ability to supply its specified current. An explanation of the contact deterioration mechanism is attempted, and a solution of the maintenance problem is suggested: a design of a bypass supply system, including isolators and automatic switches. The proposed system was tested in actual industrial conditions, namely in hospitals, where maintenance is an awkward procedure, and proved to perform adequately.

DOI:10.1049/ip-c.1988.0046

出版商:IEE    

年代:1988

数据来源: IET