IEEE Transactions on Power Apparatus and Systems

Trees are known to initiate at some microvoids and contaminants in polyethylene high voltage cables. The long term relaxation and reordering of crystallizable entities in the polyethylene known as secondary crystallization is suggested as a possible mechanism for microvoid or discontinuity formation. It is shown that both the increase in microvoid concentration with age and the radial distribution... View full abstract»

This paper presents a cable design which will allow for the replacement and salvage of the conductor of 600-volt insulated, directly-buried cables, without extensive excavation. This design, initially developed in 1964, consists of a polyethylene insulating tube/raceway and a bare conductor, the diameter of which is less than the inside diameter of the tube. The physical and electrical characteris... View full abstract»

This paper describes the design of the cross-linked polyethylene moulded straight joint for 154 kV and 275 kV cross-linked polyethylene insulated cables, the moulding method, the characteristics of the moulded insulation, and its frist application to a long distance 154 kV XLPE cable transmission line in Japan (Toyo-Ike Line of The Tokyo Electric Power Co., Inc.). View full abstract»

The main properties of modern ethylene-propylene rubber (EPR) compounds used for the insulation of medium and high voltage power cables are reviewed. View full abstract»

The widespread availability of computer terminals with graphics capability has made it possible to develop interactive software for use in Electric Power Engineering education. This paper presents a general description of the RPI graphics system and the programs now available for Power Engineering use. View full abstract»

A staged phase-to-phase fault was applied to one end of a 500 kV series compensated circuit as part of the specified acceptance tests for the series capacitor bank. This paper summarizes the pre-test planning studies, test execution, and the results of both the staged fault test and its computer simulations for the third series capacitor bank installed at the B.C. Hydro Kennedy Substation. Stabili... View full abstract»

This paper deals with overvoltages caused by self-excitation in a separated power system, which has some generators, heavy load and large shunt capacitance of underground cables and/or shunt capacitors. The condition of stability in a separated power system is analyzed and a comparison with the experimental result is presented. View full abstract»

The system operator is presented with a new aspect of the complex problem of minimum cost dispatch because of the shift, within the past few years, from unlimited energy, level cost fuel supplies to limited energy, variable cost supplies. The paper presents a dispatch method for recognizing, evaluating, and loading these limited energy, variable cost fuel blocks in a cost optimum manner. The metho... View full abstract»

A key operating question facing the control staff at South Carolina Electric and Gas Company (SCE&G) is: "How should thermal generation be coordinated with pumped-storage operation and economy purchases to minimize the total system production costs?" To answer this complex question, SCE&G dispatchers are currently using a unit commitment program which can perform global optimization. The purpose o... View full abstract»

Using step-by-step numerical integration, the steady-state solutions of HVDC converter problems are obtained by integrating until all the transients have been damped out. In general, these solutions are expensive to obtain. View full abstract»

The four-state Markov model for peaking units recommended in 1972 by an IEEE Task Group is modified to provide a more accurate representation of the operating history of thermal units in cycling operations. Two new models are also presented: one for identifying contributions to the calculated index from the various causes of outages, the other for incorporating the forced extensions of planned out... View full abstract»

Measurement system failures and modeling constraints may make it impossible for the power system state estimator to estimate bus voltage magnitudes and angles at every bus in the power system from the available real-time measurements. Such a measurement deficiency may be remedied by adding pseudo measurements of estimated bus loads. This paper presents a combined observability/measurement placemen... View full abstract»

The paper presents a methodology for the closed form calculation of electromagnetic transients in power system networks, resulting from sequential switching operations. The system is viewed from the terminals of the switch poles where a compensating voltage source is applied for closing and a compensating current source is applied for opening of a pole. The network, with frequency dependent modell... View full abstract»

This paper describes the results of an investigation of potential methods to locate fluid leaks from buried high voltage underground cable systems. Emphasis was on high-pressure oil-filled cables but many of the methods studied are also applicable to other cable types. View full abstract»

An on-line transient stability evaluation method is presented in this paper. Under some classical assumptions, the change of generator rotor angles during the transient period is described by a set of second order differential equations. This set of equations is solved by single-step high order derivative explicit integration. A new system decomposition-aggregation technique is proposed to decompo... View full abstract»

This paper describes the relevant equations and other ancillary features required for implementation of improved synchronous machine models into large scale stability programs. The improved models overcome the limitations that have been experienced with the conventional models used by most stability programs. The method of implementation proposed is computationally efficient and provides sufficien... View full abstract»

An efficient and simple hierarchical state estimation method, suitable for real-time monitoring of large-scale power systems is investigated in detail. This method exhibits inherent parallelism; it treats all sub-systems of the large system and all tielines coupling these sub-systems separately and independently. Thus, it is very flexible, allowing fast state estimation and bad data processing, th... View full abstract»

This paper describes a mathematical approach to the determination of the electrical load composition of a secondary network during cold-load re-energization. It is intended to answer two questions: What fraction of the normal steady-state demand must be restored at the time of re-energization in the most pessimistic case? What is the composition of this worse case restoration load? View full abstract»

Experimental studies of tree growth are often performed under one single set of test conditions. The aim of this work has been to systematically vary the test conditions to study their influence on tree growth in one type of XLPE cable. It was found that water in the conductor dramatically increases the number, size and growth rate of trees. In such tests the temperature of the outer screen should... View full abstract»

Response errors in the measurement of rapid high voltage irpulses are shown to be related to three parameters, while a fourth parameter defines the shortest event for which the relationships are valid. These parameters are used to demonstrate the theoretical and practical adjustment of dividers for minimum response errors. In this way the errors can be brought within acceptable limits. View full abstract»

A system has been developed to measure the electric fields in transformer oil using the electro-optic Kerr effect. The system performance was verified by measuring the electric field and space charge in nitrobenzene. The field distributions were measured in clean oil, in oil which had been used as a wash for a radiator used in a power transformer, and in oil which was removed from a transformer th... View full abstract»

The analysis of Non-Dispatchable Technology (NDT) options in the expansion plan requires accurate, computationally efficient and flexible modeling of generation uncertainties and relevant statistical interdependencies (correlations). The implementation of a suitable methodology and computational results including sesitivity analysis on the capital cost and "hardware" reliability of the NDT option ... View full abstract»

An in-house Delphi unassembled conference was used by the Bonneville Power Administration to derive a prioritized list of problems in system operation and control, and to evaluate the usefulness of the Delphi method. The questionnaires evolved through several stages, which are described. Some information for judging the validity of this Delphi exercise is supplied. An ordered list of issues, many ... View full abstract»