Showing papers in "IEEE Transactions on Power Apparatus and Systems in 1967"
TL;DR: The ac power flow problem can be solved efficiently by Newton's method because only five iterations, each equivalent to about seven of the widely used Gauss-Seidel method are required for an exact solution.
Abstract: The ac power flow problem can be solved efficiently by Newton's method. Only five iterations, each equivalent to about seven of the widely used Gauss-Seidel method, are required for an exact solution. Problem dependent memory and time requirements vary approximately in direct proportion to problem size. Problems of 500 to 1000 nodes can be solved on computers with 32K core memory. The method, introduced in 1961, has been made practical by optimally ordered Gaussian elimination and special programming techniques. Equations, programming details, and examples of solutions of large problems are given.
1,112Â citations
TL;DR: In this article, the design of a total control system for the improvement of the reliability of the generation transmission system is discussed, which is made of automatic functions, human participation, and an information system.
Abstract: Considerations necessary for the design of a total control system for the improvement of the reliability of the generation transmission system are discussed. The control system is made of automatic functions, human participation, and an information system.
295Â citations
TL;DR: In this paper, an analytical method is presented to determine these voltages for long and short lines, arbitrary ground network terminations, and any combination of skywires and counterpoise conductors.
Abstract: Since ground fault currents in high-voltage systems are on the increase, the hazards associated with transmission tower voltages during ground faults have become of concern. An analytical method is presented to determine these voltages for long and short lines, arbitrary ground network terminations, and any combination of skywires and counterpoise conductors. The proportion in which the fault current is supplied by the line on both sides of the fault location is taken into account, and the effect of fault currents flowing in parallel external circuits is also considered. The touch and step potentials at the faulted tower are determined and an assessment is given of the hazard they may represent. In a numerical example, several measures aimed at reducing this hazard are compared.
119Â citations
TL;DR: In this article, a series of tests, carried out by applying impulse waves simulating switching surges to air gaps with electrodes of different shapes, is described, and it is possible to draw some important conclusions about the influence of the electrode shape and also to single out simple rules for the predetermination of the behavior of air insulation; these rules can be particularly useful for designing purposes.
Abstract: A series of tests, carried out by applying impulse waves simulating switching surges to air gaps with electrodes of different shapes, is described. From the test results, it has been possible to draw some important conclusions about the influence of the electrode shape and also to single out simple rules for the predetermination of the behavior of air insulation; these rules can be particularly useful for designing purposes.
89Â citations
TL;DR: This paper describes a computerized method of calculating unbalanced load flow or fault currents on multi-grounded radial distribution circuits, developed by engineers of the Baltimore Gas and Electric Company, and now being used in operating and expanding their distribution system.
Abstract: This paper describes a computerized method of calculating unbalanced load flow or fault currents on multi-grounded radial distribution circuits. It was developed by engineers of the Baltimore Gas and Electric Company, and is now being used in operating and expanding their distribution system. The basic concept employed is that the electrical characteristics of any portion of an unbalanced 3-phase circuit can be represented by a 6-element wye-delta network. An operating program that can accommodate up to 750 circuit branches has been written for the IBM 7094 computer.
80Â citations
TL;DR: In this paper, a unified method of designing electrical machines is presented, utilizing the capabilities of modern, high-speed digital computers, with the objective of meeting all performance requirements at minimum cost.
Abstract: A unified method of designing electrical machines is presented, utilizing the capabilities of modern, high-speed digital computers. The objective is to meet all performance requirements at minimum cost. The general approach is described by means of two examples, a program for design of power transformers and a program for design of hydroelectric generators.
73Â citations
TL;DR: In this paper, a quantitative breakdown criterion for use in highvoltage design is derived by which spark breakdown or corona starting voltages in nonuniform fields can be calculated, and it is shown how it can give a very detailed and accurate description of known breakdown characteristics.
Abstract: The processes leading to a spark breakdown or corona discharge are discussed very briefly. A quantitative breakdown criterion for use in high-voltage design is derived by which spark breakdown or corona starting voltages in nonuniform fields can be calculated. The criterion is applied to the sphere gap, and it is shown how it can give a very detailed and accurate description of known breakdown characteristics.
72Â citations
TL;DR: In this paper, a stability study of a reluctance-synchronous machine is performed by applying the Nyquist stability criterion to the equations which describe the behavior of the machine during small displacements about a steady state operating point.
Abstract: A stability study of a reluctance-synchronous machine (synchronous-induction machine) is performed by applying the Nyquist stability criterion to the equations which describe the behavior of the machine during small displacements about a steady- state operating point. This investigation reveals that machine instability can occur at low speeds (low frequencies) even though balanced, constant amplitude, sinusoidal voltages are applied to the stator terminals. Regions of machine instability are established from the results of a digital computer study. The results of an analog computer study are included to illustrate the modes of operation which occur within these regions. Also, regions of instability for different values of system parameters are given and discussed.
69Â citations
TL;DR: In this article, the authors apply Liapunov's direct method to the study of power system stability, which is relatively new, and apply it to the case of multi-machine systems.
Abstract: Although there are many publications on power system stability, the application of Liapunov's direct method to the study is relatively new. Gless[l] used an energy integral as a Liapunov function to study 1-, 2-, and 3-machine problems. El-Abiad and Nagappan,[2] also based their studies of the transient stability of a multi-machine system with losses on energy concepts.
66Â citations
TL;DR: An all-digital simulation of an induction machine and its associated control system is described, suitable for analyzing operation either from a constant frequency, constant voltage supply, or analyzing a complete control loop with a variable frequency power source.
Abstract: An all-digital simulation of an induction machine and its associated control system is described. The simulation is suitable for analyzing operation either from a constant frequency, constant voltage supply, or analyzing a complete control loop with a variable frequency power source. The computer program which is described calculates both the transient and steady-state performance of the machine from its equivalent circuit constants. The principal element in the program is a differential equation solving algorithm using a predictor-corrector method. This predictor-corrector technique is relatively easy to program and is suitable for use with a medium size digital computer. A discussion of the various steps in the program as well as an example of an application of the program are given.
61Â citations
TL;DR: In this article, the phase advance of the first derivative was used to offset the inherent lags of the hydro unit, and the scheme is proving capable in augmenting the stabilizing effort from the limited amount of suitable fast response steam capacity available.
Abstract: Stabilization of the initial interconnection across Utah and Arizona between the Northwest and Southwest power systems has been aided by damping torques generated through special control of a unit in Grand Coulee powerplant in Washington. The special control is derived from local frequency, using the phase advance of the first derivative to offset the inherent lags of the hydro unit. The scheme is proving capable in augmenting the stabilizing effort from the limited amount of suitable fast response steam capacity available.
TL;DR: In this paper, the normal mode theory of current flow in straight, long conductors is applied to nonmagnetic, isolated, rectangular bars of various side ratios, and sufficient modal parameters have been computed to permit families of conductor resistance ratio and inductance variation curves to be given.
Abstract: The recently proposed normal mode theory of current flow in straight, long conductors is applied to nonmagnetic, isolated, rectangular bars of various side ratios. Sufficient modal parameters have been computed to permit families of conductor resistance ratio and inductance variation curves to be given. These curves may be used to estimate the alternating current parameters of nearly any rectangular conductor with an accuracy of about 0.5 percent for the resistance, and about one nanohenry per meter for inductance.
TL;DR: In this paper, the results of several tests on plane capacitors were given, from which the steady-state resistivity of four different kinds of paper and impregnants appear to be almost identical from this point of view.
Abstract: In dc cables the resistivity of the insulation is a very important parameter, as it determines the stress distribution and the power losses in the insulation. This paper gives the results of several tests on plane capacitors, from which the steady-state resistivity of four different kinds of paper and impregnants appear to be almost identical from this point of view. The transient behavior of one of the dielectrics is also shown, giving the current density as a function of time after the application of a direct voltage, for different temperatures and stresses.
TL;DR: In this paper, a combination of energy and force concepts are applied to a study of several aspects of the contact bounce phenomenon, and the significant effect of the support structure upon bounce is analyzed by means of simple models.
Abstract: A combination of energy and force concepts are applied to a study of several aspects of the contact bounce phenomenon. Energy dissipation at the contact interface is studied by quasistatic and dynamic techniques. Both work hardening and deformation result in a progressive reduction in the energy dissipating properties of common contact metals. The significant effect of the support structure upon bounce is analyzed by means of simple models leading to criteria for the minimization of contact bounce duration.
TL;DR: In this article, a method of predicting voltage gradients and body currents utilizing both analytical and numerical techniques in the solution of Laplace's equation is presented, which can be used to predict both currents and gradients for new designs and voltage levels.
Abstract: As voltage of electrical transmission systems increases, live line maintenance by the barehand method becomes increasingly necessary to meet the requirements of system reliability. Of more importance is its value to the workman in permitting him to use power and hand tools without the strain which would be encountered with the long, heavy, hot line tools required at these voltages. Protection of the workman from exposure to high-voltage gradients and body currents is easily attained through Faraday cage-type shielding, as has been proved by an extensive test program described in this and companion papers. This paper develops a method of predicting voltage gradients and body currents utilizing both analytical and numerical techniques in the solution of Laplace's equation. The results are compared with field measurements and excellent agreement is obtained. The method described can therefore be used to predict both currents and gradients for new designs and voltage levels as well as for existing designs and voltages.
TL;DR: In this paper, single suspension insulator units of several types as well as multi-unit strings were studied in a large refrigerated chamber and rime ice of various densities was deposited on these insulators.
Abstract: Single suspension insulator units of several types as well as multi-unit strings were studied in a large refrigerated chamber. Rime ice of various densities was deposited on these insulators. The increase of leakage currents, the reduction of flashover voltages, and the alteration of voltage distributions along insulator strings caused by the presence of the ice were measured. The effects of various protective coatings on the insulator performance were examined. The process of insulator flashover under rime ice is compared with that under the usual types of industrial and marine pollution at temperatures above freezing point.
TL;DR: An induction machine, fitted with two independent sets of windings on the stator, and two suitably interconnected sets of rotor windings, can be used as a variable speed machine in which the slip power from the rotor circuits is transferred by induction to one set of stator windings. From these it can be returned to the supply via a low power frequency converter which handles slip power only as discussed by the authors.
Abstract: An induction machine, fitted with two independent sets of windings on the stator, and two suitably interconnected sets of rotor windings, can be used as a variable speed machine in which the slip power from the rotor circuits is transferred by induction to one set of stator windings. From these it can be returned to the supply via a low power frequency converter which handles slip power only.
TL;DR: In this article, a number of factors related to control of generation and power flow on interconnected systems are analyzed, and the effectiveness of regulation within an individual control area can be judged.
Abstract: A number of factors related to control of generation and power flow on interconnected systems are analyzed. Criteria by which effectiveness of regulation within an individual control area can be judged are examined. System control error is defined and its relationship to system frequency deviation and to system stored energy developed. In particular, inadvertent interchange is explored and its relationships to system time error for an area that regulates to zero control error is developed. Conditions under which the algebraic summation of inadvertent interchange around the interconnection would be zero are defined, and operating conditions when this would not be true are identified. This leads to an evaluation of the technique, used by some control areas, of correcting for inadvertent interchange by a unilateral change of net interchange schedule. The adverse effect which such unilateral action can have on the inadvertent accounts of other areas is pointed out. Quantitative relationships are derived which show the relatively small influence which unilateral schedule changes have on system frequency and time error. Also examined and noted to be of limited validity is the practice of deducting the time integral of the bias term from total inadvertent interchange to obtain unintentional inadvertent.
TL;DR: In this article, the use of the insulating properties of wood in transmission line practice is discussed, where the electrical properties of the wood and the possible damaging effects of surge currents and power frequency leakage currents are considered.
Abstract: This paper deals with the use of the insulating properties of wood in transmission line practice. The electrical properties ?impulse strength and arc quenching?and the possible damaging effects of surge currents and power frequency leakage currents are considered. Prediction of the lightning performance of shielded and unshielded lines is discussed, and it is shown that the impulse strength and arc quenching properties of wood influence performance, the latter property being the dominant one for unshielded lines. A design criterion using this arc quenching property has been developed from experimental data on arc characteristics.
TL;DR: In this paper, the effects of HV 60-Hz ac fields on human beings were investigated and the protection offered by Faraday screens was discussed, and the results of a series of physiological examinations that were carried out on 11 linemen, some of whom used conventional hot stick methods and others worked barehanded from an aerial bucket connected to an energized conductor.
Abstract: This paper covers an investigation of the effects of HV 60-Hz ac fields on human beings. Experimental results of the intensity of the electric fields to which linemen are subjected when doing maintenance work on energized HV lines are presented. The protection offered by Faraday screens is discussed. The results of a series of physiological examinations that were carried out on 11 linemen, some of whom used conventional hot stick methods and others worked barehanded from an aerial bucket connected to an energized conductor, are presented. The examinations, which extended over a 42-month period, were conducted by members of the staff of The Johns Hopkins Hospital, Baltimore, Md.
TL;DR: In this paper, male mice were exposed to a 60-Hz ac electric field by placing them, in cages, between parallel plates energized to create a field, initially unperturbed, of 4 kV/in.
Abstract: Twenty-two male mice were exposed to a 60-Hz ac electric field by placing them, in cages, between parallel plates energized to create a field, initially unperturbed, of 4 kV/in. In the course of 10?months, each animal had an accumulated exposure time of nearly 1500 hours. These animals, and a parallel control group (essentially identically handled but receiving no exposure to electric fields), were repeatedly bred and observed to determine whether there were any effects, harmful or beneficial, as a result of the exposure.
TL;DR: In this article, the authors estimate the limit of the possible transmission line voltage and clarify the mechanism of discharge in the air under dry conditions, and test on the switching surge flashover of long air gaps.
Abstract: The purpose of this paper is to estimate the limit of the possible transmission line voltage and to clarify the mechanism of discharge in the air. Tests were performed on the switching surge flashover of long air gaps under dry conditions. The flashover voltages of the switching surge with the duration of wave front 180 ?s were obtained up to 13 meters for rod-plane gaps for positive polarity. The tests were performed at the Shiobara Outdoor Laboratory.
TL;DR: In this paper, the authors show possible ferroresonant overvoltages on wye-delta transformer banks during single-phase switching as a function of transformer size and lateral length.
Abstract: This paper shows possible ferroresonant overvoltages on wye-delta transformer banks during single-phase switching as a function of transformer size and lateral length. Application guide is based on industry standard voltage criteria. Secondary loading and neutral resistor requirements are given. A neutral resistor presents an attractive solution in many cases. Simple to use equations are given to allow application of test data.
TL;DR: The Piecewise Method of solution, better known as Diakoptics, is a procedure for solving large-scale system problems by tearing or decomposing.
Abstract: The Piecewise Method of solution, better known as Diakoptics, is a procedure for solving large-scale system problems by tearing or decomposing. The problems to be analyzed seem to grow at a very rapid pace. Neither the increased computer speeds nor the computer core storages seem to keep up with the size and complexity of the problems to be solved. Diakoptics appears to be a good tool with which to supplement the computer, or computers, to solve large-scale system problems.
TL;DR: In this article, the effects of wind on corona discharges from HV dc transmission lines were studied using two laboratory models, one model was used for studying the corona vs. wind characteristics of discrete metal projections from smooth conductors, while the other dealt with corona on stranded conductors.
Abstract: The effects of wind on corona discharges from HV dc transmission lines were studied using two laboratory models. One model was used for studying the corona vs. wind characteristics of discrete metal projections from smooth conductors, while the other dealt with corona on stranded conductors. The investigation encompassed both 2-conductor and conductor-to-plane configurations at wind speeds up to 50 miles per hour. It was found that both corona loss and radio-influence voltages (RIV) were sensitive to wind in the 2-conductor configuration but not in the conductor-to- plane configuration. The results are correlated with previous findings and with the theories of corona discharges.
TL;DR: In this paper, the authors present a digital computer program which enables the rapid computation of dynamic stability limits for a single synchronous machine connected to an infinite receiving system through a transmission line.
Abstract: The ability to calculate the dynamic stability limits of synchronous machines is of increasing importance today as generation and transmission equipment are being applied with higher reactances and correspondingly lower stability margins. This paper describes a digital computer program which enables the rapid computation of dynamic stability limits for a single machine connected to an infinite receiving system through a transmission line. Effects of excitation and prime mover power controls are included making the program a valuable tool for the equipment designer. Typical results illustrate the effect of terminal voltage, transmission line reactance, and machine inertia on the stability limits. The concept of damping ratio as an index to relative stability is discussed and illustrated. Also shown are the effects of neglecting saturation and other second-order effects on the calculation of dynamic stability.
TL;DR: In this paper, the authors identify and photograph the foul-weather coronas occurring on a high-voltage transmission-line conductor and to establish their radio-noise importance, and confirm laboratory tests were made at 230 and 345 kV.
Abstract: This study was made to identify and photograph the foul-weather coronas occurring on a high-voltage transmission-line conductor and to establish their radio-noise importance. On the most tested 230-kV line, snow impingement plumes caused radio interference (RI) to 90 times, and water drop spray plumes to 75 times, that of the base fair-weather noise level. Foul-weather RI caused by snow, rain, fog, ice, and condensate associated with the conductor overrode RI generated on insulators, accessories, hardware, and weathered conductor protrusions. H/sub 2/0 particles in different forms were present in the conductor environment for one-fifth the yearly time. The conductor surface gradient, the rate of decay outward from the conductor, the total conductor surface area, H/sub 2/0 particle size and formation, and air velocity over the conductor are important to both particle attachment to the conductor and to the severity and form of corona. This corona occurs as plumes, impingement plumes, spray plumes, glows, and microsparks. Confirming laboratory tests were made at 230 and 345 kV. Confirming observations were made on 345-and 500-kV lines. Corona losses were caused by impingement plumes during snowstorms and principally by spray plumes in rain.
TL;DR: In this paper, a geometrical model technique, involving comparison of lightning voltages measured on the models with those obtained from linear traveling wave calculations, enables realistic estimation of the value ascribed to tower surge impedance, an important parameter in the calculations.
Abstract: A method has been developed to predict the probability of a double circuit outage on double circuit lines. Traveling wave techniques are used to account for nonlinearities such as corona, attenuation, and phase conductor flashover as its time iterative approach enables alteration of design parameters at each time increment. A geometrical model technique, involving comparison of lightning voltages measured on the models with those obtained from linear traveling wave calculations, enables realistic estimation of the value ascribed to tower surge impedance, an important parameter in the calculations.
TL;DR: In this article, the influence of air density on switching surge and impulse flashover strength of transmission line insulation was evaluated at the Leadville EHV Test Facility of the Public Service Company of Colorado (PSC) and Project EHVM at Pittsfield, Mass.
Abstract: Flashover tests were conducted at the Leadville EHV Test Facility of the Public Service Company of Colorado and Project EHV at Pittsfield, Mass., to obtain comparative data to evaluate the influence of air density on switching surge and impulse flashover strength of transmission line insulation. The tests showed that negative polarity flashover voltages are greater than those of positive polarity. Therefore, positive polarity will be the critical requirement for transmission line design for switching surge duty.
TL;DR: In this paper, the linear governing equations of L. M. Hovey are extended to describe the major nonlinearities of a hydro electric generating set, and the resultant nonlinear governing model can be used to simulate the small and large signal transient response of an isolated generating set under any loading condition, and comparisons of such simulations with test results are given.
Abstract: The linear governing equations of L. M. Hovey are extended to describe the major nonlinearities of a hydro electric generating set. The resultant nonlinear governing model can be used to simulate the small and large signal transient response of an isolated generating set under any loading condition, and comparisons of such simulations with test results are given. The analysis of the paper demonstrates that Hovey's method of calculating temporary droop from a closed dashpot step response transient is inaccurate, and a corrected method is presented.