The Kluwer International Series in Engineering and Computer Science

Fudeh H., Ong C.

The coupled-circuit approach is used to derive a mathematical model of a general m-n winding machine in which all MMF harmonics are taken into account. The model, which is applicable to both squirrel cage and phase- wound rotors, has provision for cage rotors with non-integral number of rotor bars per stator pole-pair. The effects of the transformations from polyphase to a-P-0 and to d-q-0 on the machine equations are analyzed. It is shown that the polyphase to a-P-0 transformation, when applied to the stator and rotor of the m-n winding machine, divides the harmonics into different groups of harmonics with possible interaction, whereupon each group of harmonics can then be represented by an a-P or a zero component circuit. This result shows that the usual assumption of representing the cage rotor by independent harmonics circuits is, in general, not valid. It is also shown that the polyphase to rotating d-q transformation is applicable when only one harmonic from each a-P component is to be considered, otherwise a new problem of separating the harmonic voltages within each a-P component is created.

Willis H., Tram H., Powell R.

An automatic, computerized procedure is used to generate a representative model of a large distribution system. Although the distribution system may have hundreds of feeders, the representative model has only 12, reducing manpower and computer costs in studying major issues such as voltage regulation, equipment loading, and operating policy. This computerized procedure reduces the distribution system to a 12 feeder model using a clustering method that groups feeders into sets of feeders with similar characteristics.

Wood H.C., Johnson N.G., Sachdev M.S.

Digital protection algorithms are becoming more complex as the cost of computational equipment continues to decrease. In particular, optimal response digital filters, such as Kalman filters, can be implemented on presently available devices. Optimal filters are not yet extensively applied because they appear complex and engineers have not become familiar with their use. This paper presents the basics of the Kalman filtering technique in power systems terminology and illustrates its use for estimating rotating phasors. Sample designs are presented for voltage and current phasor estimation during system transients. A method for including decaying dc and harmonic frequency components in the filter design is also described and sample results are presented.

van den Bosch P.P.

This paper deals with the formulation and solution of the optimal dynamic dispatch problem owing to spinning-reserve and power-rate limits. The power production of a thermal unit is considered as a dynamic system, which limits the maximum increase and decrease of power. The solution is obtained with a special projection method having conjugate search directions that quickly and accurately solves the associated non-linear programming problem with up to 2400 variables and up to 9600 constraints.

Monticelli A., Murari C.A., Wu F.

The standard approach to the solution of the weighted least square (WLS) state estimation in power system is the iterative normal equations method. Occasional ill-conditioning has been experienced with this method. Recently alternative solution approaches based on orthogonal transformations have been proposed. Sparsity generally suffers in these methods. In this paper, the network condition which causes ill- conditioning is studied. A hybrid approach which enjoys the same numerical robustness of the orthogonal methods with sparsity close to the standard WLS method is presented. The modification needed to implement the hybrid method on an existing standard WLS state estimation program is quite small.

Yamayee Z., Hakimmashhadi H.

Predicting expected generation for different power plants as well as the system's total expected production cost is an integral part of quantitative power system analyses. Numerous publications presenting exact as well as approximate methods of solving stochastic production simulation problem exist in the literature. However, there is no one publication where a comprehensive review of this extremely important topic is presented. Such a review is the subject of this paper.

Garrett D., Pruitt J.

This paper describes some problems which can be encountered when using the average potential method to analyze sub- station grounding systems. Several examples are shown which illustrate how some of the assumptions made in developing the average potential method affect the accuracy of the results. The sources of error in some of these assumptions are explored. The paper concludes that caution should be exercised in interpreting the results of this analysis technique and suggests further research to determine the error to be expected and/or corrections to the method.

Ando M., Schweitzer E., Baker R.

A prototype data collection system was developed in order to acquire field data as a part of the development of HVDC fault location techniques. The system was installed at the Celilo Converter Station of the Pacific HVDC Intertie, owned by the U. S. Department of Energy-Bonneville Power Administration in May, 1983. It monitors two line voltages, one neutral voltage, and two line currents. It also has an event detection function to trigger saving data onto a diskette. In this paper (Part I) the data collection system hardware is described, and several field data are plotted and analyzed. Development of an HVDC fault location algorithm and its evaluation using field data are given in the second paper, Part II.

Ando M., Schweitzer E., Baker R.

A new technique for locating faults on a two-terminal HVDC transmission line which uses information from only one end of the line is developed and analyzed. The new technique uses successive reflections generated by faults. Using a differentiator and smoother the slopes of the transients are computed. Furthermore, the best estimated peaks of the slopes for the first two consecutive transients are obtained. The time interval between these two peaks is proportional to the fault location. The new technique is referred to as simple passive reflectometer (SPR). Field data obtained at the Celilo converter station of the Pacific HVDC Intertie (see the companion paper [1]) are used to evaluate the SPR. The agreement with a two-ended system is within one mile over the length of the 850-mile Pacific HVDC Intertie transmission line.

McLaren P., Rajendra S.

The use of fault initiated travelling-wave components in the protection of power lines can provide for faster relay operation. This paper describes the development of several new techniques based on the high frequency travelling-wave information contained in the post-fault voltage and current signals for the protection of teed circuits. The techniques developed have been incorporated in a generalised algorithm for application as a high speed direct-intertrip distance scheme.

McLaren P., Rajendra S.

In a preceding paper [1], the authors had described new techniques based on the h.f. travelling-wave information contained in the post fault voltage and current signals. In an attempt to present the underlying principles without undue complications, the study was limited to a lossless, frequency independent single phase line model.

Den Bosch P.P.

This paper describes and compares several fast algorithms for the solution of the static dispatch problem for thermal power units without transmission losses. Both linear, quadratic and non-linear functions are discussed to describe the fuel costs. Moreover, units that use two fuels at the same time and units with fuel constraints are discussed.

Sanghvi A., Levy R., Wharton J.

This paper describes a new customer preference based approach for planning demand- management programs. It utilizes the concept of perceived value of electric service to consumers. After introducing and defining this concept, its central role in major aspects of utility planning is discussed.

Trussell H., Wang J.

Adaptive least mean square (LMS) filters are shown to be effective in reducing harmonic noise on distribution power lines. The efficiency of these filters can be improved by imposing constraints.

Vuong G., Valette A.

The algorithm reported here has been implemented on IREQ's Transient Stability program (ST600) since 1980. Its strong convergence allowed many severe disturbances on Hydro-Quebec's system to be properly simulated. No convergence problems directly attributable to the basic algorithm have been observed.