IEEE Transactions on Power Apparatus and Systems

The effect of perturbation of currents of multi-winding transformers, on the stored magnetic energy in the magnetic field associated with these apparatus is used to calculate the saturated incremental, apparent and effective self and mutual winding inductances. The method is applied here to single phase and three phase transformers. A finite element magnetic field model is used to calculate the en... View full abstract»

The study of the torque and force distributions in a superconducting alternator shows that certain combinations of stiffness and inertia constant of the rotor screens can cause very large resonance torques and forces. The free outer rotor can also resonate. An effective means of avoiding the resonance is suggested and discussed. A method of transferring oscillating torques from the weaker member t... View full abstract»

The paper presents a new weighted leastsquare scheme for differential protection of power transformers using digital techniques. The differential current waveform is modelled as a sum of decaying dc, fundamental and selected higher harmonic components. The model coefficients are established by using a least-square filtering technique for the sampled data. A root mean square error criterion is esta... View full abstract»

This paper provides the power system designer with some guidelines concerning what measure of stability improvement can be expected with highresponse vs. normal response excitation systems for turbine-generators. Transient and oscillatory stability study results are illustrated showing how critical fault clearing time (CFCT) and unit damping performance vary as a function of excitation system resp... View full abstract»

The three dimensional finite element formulation of eddy current problems with ac sinusoidally time varying excitations is given using magnetic vector potential and complex phasor representation. First order tetrahedral elements are utilized. In this formulation, magnetic saturation is neglected. Three values of magnetic reluctivity, vx, vy and vz, are defined within each tetrahedral element, whil... View full abstract»

The mechanical stress of metal-enclosed switchgear installations due to fault arcs can be predicted by means of pressure calculation. In this paper a number of calculation methods is discussed. The results of pressure calculation are compared with pressure measurements performed in model switchgear cubicles. It is shown, that simplifying assumptions in some calculation methods lead to inaccurate r... View full abstract»

In applying microelectronic techniques to protective and control equipment in the power system, there is an important subject to be solved, which is the assurerance of long-term reliability. From this viewpoint, countermeasures against environmental conditions, for example temperature rise, electro-magnetic interference and dust are reconsidered. View full abstract»

This paper is concerned with the investigation of a systematic corrective control approach for the transient emergency state problem of the power system. The proposed new control framework involves distributing the task of system transient stability margin improvement among several local facilities dedicated to the various subsystems comprising the power system. The functional design of the variou... View full abstract»

The functional design of a local control strategy considered suitable for bulk power system disturbed into transient emergency state was set forth in the companion paper [1]. It utilized a particular control procedure based on an adaptively specified angle- velocity threshold limit criteria. In order to consolidate the validity of the strategy, this paper describes its algorithmic implementation a... View full abstract»

This paper is one of a series prepared for use in Current Operational Problems (COPs) forums with the goal of focusing the attention of the industry on high priority problems faced by those who are involved in the actual operation of power systems. View full abstract»

Streaming electrification of large power transformers is discussed here from the standpoint of characteristics of insulating oils used in them. View full abstract»

Transformer models for system studies derived without taking into account the frequency dependency of its magnetizing branch are not adequate for representing the transformer performance over a wide range of frequencies and operating conditions. This paper describes a procedure for taking into account the frequency dependent characteristics of the transformer based on an analysis of the electromag... View full abstract»

This bibliography was prepared for Working Group 70.1 on Gas Insulated Substations of the IEEE Substation Committee. Certain entries were published in the IEEE Transactions on Power Appatatus and Systems Vol. PAS-94, No. 4, July/August 1975, pp. 1425-35; Vol. PAS-96, No. 4, July/August 1977, pp. 1280-87; and Vol. PAS-99, No. 1, January/February 1980, pp. 389-401. Due to the growth of research unde... View full abstract»

This paper describes the results of an investigation into how steam fog parameters affect the withstand voltage of artificially contaminated insualtors by the fog withstand method. We established the correlation between the steam flow rate and liquid water content of the fog. The fog withstand voltage showed a lower value with little dispersion at about 3 to 10 g/m3 of the maximum liquid water con... View full abstract»

The opportunities for applying coomputer graphics and com puter-aided design (CAD/CAM) to switchgear engineering drawings are examined in a case study of one switchgear manufacturer's computer system. This system is of unusual interest because it is particularly strong in two features which are seldom achieved: 1) flexibility in drawing layout and content, and 2) greater computer assistance in mos... View full abstract»

Due to the increasing demand for electrical energy, the transmission capacity of existing power transformer substations must be correspondingly increased to prevent their overloading. This paper represents a new method for the optimal expansion for such substations. The optimized objective function includes the total annual cost of both the original already existing power transformers and the new ... View full abstract»

A 77 KV 40 MVA gas-vapor cooled transformer has been developed as a prototype of substation transformers, which is directed to nonflammable and lightweight properties. To examine the operating reliability of the transformer, the reliability test has continued since July, 1981 at the Hokusetsu substation of KEPCO (Kansai Electric Power Co., Inc.). This report will cover the development work on ther... View full abstract»

This paper presents a review of the state of the art and practice of transmission line tower design with specific attention to structure loading conditions, comparison of results using different tower analysis techniques and a comnentary on some criteria of the ASCE Manual 52 "Guide Ebr Design of Steel Transmission Towers." View full abstract»

This paper studies the experimental results of the quasi-state high field dc conduction current, and changes occuring in the molecular structure of aged transformer oil, sampled from EHV transformer operating for the last five years. Aged oil was compared with fresh transformer oil and liquid paraffin. It was found that aged oil exhibits higher conduction than both of the other oils through 600 se... View full abstract»

In Japan it has recently become necessary to shorten the interphase spacing in overhead transmission lines because of land limitations and economical considerations. In this connection, the authors have attempted to analyse, in-depth, the possibilities of shortened interphase spacing via conductor swinging caused by wind effects: one of the important factors in the design of more compact overhead ... View full abstract»

This paper describes a computer program developed for the study of the growth of corona streamers from a lightning rod. The basic physical processes of electrical discharge are applied in the model. From results of computer studies, it was found that the determination of striking distance cannot rely solely on the state of growth of the upward streanier. The attractive effect of the lightning rod ... View full abstract»

This paper describes the design prodedure and the results of field tests on mechanical performances of insulator assemblies newly developed to support octagonal-bundled conductors for 500-kV bulk power transmission. Taking account of conductor-motion-induced peak tensile load, fatigue, torsional torque and others, a successful design has been achieved in two prototype assemblies for such heavy mec... View full abstract»

Experience from various kinds of tests as well as from service of BNC impregnated power capacitors produced during a 4 year period is reviewed. View full abstract»