EHV Transmission Lines Research Articles

Simulation of EHV Transmission Line Flashovers Initiated by, Bird Excretion

During the past two years, unexplained flashovers have caused 32 outages on the Bonneville Power Administration 500 kV ac transmission lines. Tests reported in this paper indicate that some of these unexplained flashovers may have been caused by large birds and leave little or no evidence of the cause. It is also shown that this mechanism may cause flashovers on ehv dc transmission lines.

Electrostatically Induced Voltages and Currents on Conducting Objects under EHV Transmission Lines

A study is made of the steady-state short circuit current Is.c., and open circuit voltage, Vo.c., to ground for conducting objects under E.H.V. transmission lines. This is carried out in a computer program and on a scaled down laboratory model of a transmission line. In addition, tests are conducted at the American Electric Power Service Corporation and Westinghouse Electric Corporation E.H.V. test site at Apple Grove, West Virginia[1]. The Apple Grove results are used for comparison with the other two approaches. Values of Is.c. within a few percent of the field data and of Vo.c. within about 30 percent are predicted by the computer program. For the transmission line model, the measured values of Is.c. are within a few percent of the Apple Grove measurements and the values of Vo.c. are within approximately 15 percent.

Insulator Crossarms for 345-KV EHV Transmission Line

Insulator crossarms for 345-kv EHV transmission line have been developed and tested. They use four solid-core post insulator columns (quadruped type) or two solid-core post insulator columns and two disc insulator strings (Twin-arm type) to form a tetrapod mounted horizontally from the tower. They are characterized by making possible narrower right-of-way, more compact tower dimension, and supporting higher mechanical load.

Radio Noise, Audible Noise, and Corona Loss of EHV and UHV Transmission Lines Under Rain: Predetermination Based on Cage Tests

Radio noise, audible noise, and corona loss quantities dependent only on the corona phenomena at the conductor surface were determined by means of tests on conductors in cages. These quantities were then utilized to predetermine radio noise, audible noise, and corona loss for typical lines under rain. The dependence on diameter and number of subconductors was investigated. Using these data, the noise and loss characteristics of representative UHV transmission lines were plotted.

Transient Electrostatic Induction by EHV Transmission Lines

Transient electrostatic induction by EHV lines on objects such as large vehicles is studied. Attention is drawn to the need of further investigation with regard to hazards to persons touching the object and being submitted to current pulses of very short duration. An analytical expression for the electrostatically induced voltage wave is derived. The calculated numerical values are checked experimentally on the air model and the results show good agreement.

Audible Noise and Visual Corona from HV and EHV Transmission Lines and Substation Conductors - Laboratory Tests

The results of laboratory studies and preliminary field tests exploring the effects of conductor size and bundling on audible and visual phenomena associated with corona in wet weather are presented. Tubular conductors in five diameters of 1.063 to 2.375 inches were tested. To the authors' knowledge, this is the first paper to systematically develop the information necessary to estimate audible noise and the visual aspects of conductor corona on the variety of conductor sizes used for 345 kV to 765 kV and higher.

EHV AC Parallel Transmission Line Calculations with Application to the Near Resonance Problem

The use of shunt reactors with EHV transmission lines has introduced new problems, one of which is induction of high voltages on a de-energized circuit of two parallel lines. This paper presents the matrix equations used in developing a digital computer program which takes into account the effects of electromagnetic induction, electrostatic coupling, distributed lines, and transposition. The computer program may also be used to calculate the effects of shunt reactors, series capacitors, and loads. The equations can be adapted to a wide range of applications, although the examples for this paper have been limited to the near resonance problem of parallel transmission lines.

The story of Bonneville Power: 1937-1968-1987 ... Thermal generation, EHV transmission, telecommunications, automation, and service reliability

The present thrust of BPA, as it reaches toward the goals of the future, is along the parallel lines of simultaneous planning, design, and development of 1. Long-distance EHV transmission lines to expanding and emerging industrial load centers in the Pacific Northwest and Southwest. 2. Digital controls, on a comprehensive systemic basis, to replace certain analog and manual controls. 3. An expansion of the telecommunications network for the instantaneous transmission and reception of data. 4. A long-range philosophy for service reliability that will minimize outages and service interruptions. These objectives will be closely coordinated with the plans of the Bureau of Reclamation, Corps of Engineers, and other public and private agencies for the construction of new power dams, the installation of additional generating units at existing facilities, and the building of thermal generating plants to meet the power demands of the next two decades.

Computer Analysis of Electrostatically Induced Currents on Finite Objects by EHV Transmission Lines

A method is presented which allows the evaluation of electrostatically induced currents by EHV transmission lines in objects where fringing effects are not negligible and consequently the problem cannot be reduced to the two-dimensional case. A digital program is developed based mainly on experimental results obtained on an air model, the validity of which is shown by comparison with measurements made in the field and in the electrolytic tank. General equations are derived based on these results and a digital program is established for their solutions.

Determining Maximum Overvoltages Produced by EHV Circuit Breaker Closure

A method of determining voltage levels due to energizing or reclosing EHV transmission lines by using traveling phasor concepts is described. The major advantage over previously described methods is economy in computation since the energizing phase need not be varied. Comparisons with field tests and analog results show good agreement.

A Method for Analysis of Radio Noise on High-Voltage Transmission Lines

A technique is described for approximating the effect of various factors on the radio noise level, due to conductor corona, on EHV transmission lines. The technique is essentially one of comparison. Relations are given in the Appendix for calculating the conductor gradients and results are presented in curve form. The application is intended only for comparison of radio noise generated by conductor corona on ac lines, with conductors ranging only from 0.3 to 1.3 inches radius (1.5 to 3.3 cm) and for the frequency range from about 0.2 to 1.6 MHz. If an existing line has been evaluated statistically the technique can be used to approximate the radio noise level of another line. A relation is also given for obtaining curves of 3-phase voltage to conductor radius for the same radio noise generation. Because of possible conductor surface differences and environmental differences, which cannot be too accurately evaluated, care is necessary in any final estimation of the average radio noise level.

Extra High Voltage Line Outages

The placing in operation of transmission lines of 345 kV and higher made it desirable to update previous reports on transmission line operation. Information on EHV transmission lines was obtained from operating companies and correlations were attempted between design characteristics and operating results. A wealth of information was obtained, sorted out, and is presented in tabular form and should be of value to transmission line designers and operators and system planners.

Radio-Noise Levels of EHV Transmission Lines Based on Project EHV Research

The results of three years of experimental and theoretical research on transmission-line radio noise at Project EHV are presented. Computer programs were developed to process the data on a statistical basis, and as output provide both histograms and regression analyses for four test configurations operated at the 500-and 700-kV levels. Fair weather radio-noise levels were found to be significantly affected by relative humidity, relative air density, and absolute value of wind velocity, and these relationships are discussed. Wet-weather effects are presented and discussed. Both fair-weather and wet-weather experimental results are incorporated in a theoretical analysis of transmission-line radio noise resulting in a procedure which enables the transmission-line designer to predict, in advance of construction, average fair-weather and wet-weather radio-noise profiles for EHV transmission lines.

Closure to “South America's First EHV Transmission Line”

Closure to “South America's First EHV Transmission Line”

The Large Vacuum Drying Systems for Electric Cables

Recently the demand for electrical energy has been increasing rapidly, hence the EHV underground cables as well as the EHV transmission lines are repuired.As the insulation of these EHV cables, roil impregnated papers are generally in use. The electrical characteristics of this material is influenced very much by the degree of vacuum drying.This paper describes the large vacuum drying systems for electric cables set recently in our company which has the newest vacuum pump systems. It consists of a vacuum tank and pumping system as follows : (a) [vacuum drying tank] of internal diameter 5000mm, internal depth 3500mm and volume 60m3.(b) pumping system consisting of a main pump and its fore pumps, i. e.Mechanical booster pump (3450 M3/hr) as a main pump and mechanical booster (1030 M3/hr) Oil Rotary pump (3000 l/min) and Nash pump (4700 l/min) as fore pumps.

South America's First EHV Transmission Line

Line described is first step in implementation plan for construction of extra h-v transmission network that will link major generating plants and load centers in Brazil; summary of basic data and factors considered in design and selection of materials for line; alinement is described and construction methods used are explained; line was placed in commercial service in Aug 1960, operating at 132 kv; it is expected that 345-kv operation will begin in latter part of 1962.

Effect of bundle conductor field on EHV transmission line design

A description is presented of some control shield designs used commercially at 345 and 460 kv, along with results of laboratory tests indicating the trend of the art for multiconductor systems above 460 kv. Improvements in electrical performance and reduced capital costs are shown possible with towers designed for new suspension hardware developed for multipleconductor bundles.

Economics of Single and Bundle Conductors for Extra-High-Voltage Transmission

1. A method has been developed whereby the optimum configuration and conductor area may be determined for a given EHV transmission line, taking into account all the parameters which have economic significance. 2. This method is general, and applicable to a wide range of system configurations, transmission distances, voltages, and loadings per circuit. Economic evalution factors may be varied to agree with available cost data, and the judgment and policies of the utility management. 3. This method is embodied into a digital computer program for the IBM705 computer, providing rapid computation of any case to be investigated. 4. Fifty-eight different cases were investigated in this study, to determine the effect of varying the system parameters and the economic evaluation factors over a wide range of values which are of practical interest for the United States and Canada. 5. Annual cost differentials between the minimum cost points for the various configurations are considerable and correspond to several per cent of the annual charges on the line investment. 6. The optimum configuration depends upon the particular values of the system parameters and economic evaluation factors. Therefore it is difficult to draw over-all conclusions, valid for all cases. Rather, each specific case will have to be investigated separately according to the method described in this paper. 7. In general, as the load per circuit increases, relative to surge impedance loading, the number of conductors per phase corresponding to the optimum configuration also increases. 8.

Relationship Between Corona and Radio Noise on Transmission Lines II. Conductor and Insulator Corona

The basic goal of our past studies and our future plans is to strive for a means for predicting the RI level of any proposed EHV transmission line by corona measurements of its components. Our general experimental program directed toward this end is outlined as follows: 1. Find a correlation between radio noise and pulses of known characteristics with simple corona sources. 2. Determine whether this relationship can be extended to conductors and insulators which are the primary sources of radio noise on transmission lines. 3. Determine whether this relationship can be extended to pulses which are applied to an actual line and the radio noise radiated from this line. 4. Determine the pulse generation characteristics of typical configurations and sizes of conductors. This would also include the effects of humidity, surface conditions, temperatures, aerosols, and other factors affecting pulse generation. 5. Determine the effective pulse generation of a section of a transmission line of varying lengths and the RI level derived thereof for various atmospheric conditions due to aging. The first three parts of this program have essentially been completed. The next two parts are presently being studied. It is hoped that at the completion of this program a comprehensive picture of the RI performance of transmission lines can be predicted.