High Phase Order Transmission Research Articles

High Phase Order Transmission Line Fault Types

For high phase order (HPO) transmission systems, a major hurdle to overcome is the fault analysis and protection studies needed to guarantee successful implementation. This paper presents new equations which calculate the number of fault types and significant fault types of n-phase transmission lines. In addition, this paper defines and explains symmetrically significant fault types for HPO transmission systems. Lastly, this paper figuratively shows the significant fault types and symmetrically significant fault types for multiple HPO systems, n = 3, 4, 5, 6, 9, and 12. The equations and figures presented in this paper will assist in fault analysis and protective relay designs for HPO systems. The equations presented are used to determine the number of fault types a relay will need to account for, and the figurative approach shows the faults to be studied before HPO implementation.

Transposition and Voltage Unbalance in High Phase Order Power Transmission Systems

—High phase order systems have been proposed at the early inception of power transmission engineering, but few direct applications have been made. High phase order transmission should be considered as an alternative in the case of high power density applications. In this article, an analysis of transposition of high phase order overhead transmission lines is presented and voltage unbalance in high phase order systems is considered. Definitions are presented for “fully transposed” and “roll transposed” along with advantages and disadvantages of each. A generalized voltage unbalance factor is introduced and utilized to determine the benefits of transposition. The generalized voltage unbalance factor is compared with three other possible unbalance factors to determine if the generalized voltage unbalance factor is an appropriate indication of unbalance. Exemplary results are presented for 6-phase and 12-phase designs. Conclusions show that the generalized voltage unbalance factor is a good indication of transmission line voltage unbalance and certain configurations may not need full rotation transposition to minimize the unbalance factor. The transposition analysis and voltage unbalance are considerations in the assessment of high phase order as a high power transmission alternative.

An Important Study of Transverse Faults on Twelve-Phase Power Systems

Recently there has been growing interest in the technology of high-phase order power transmission, in place of conventional three-phase power transmission, for increasing the power transmission capability of overhead electric power transmission rights-of-way. One of the most important items in applying high-phase order transmission systems (12-phase systems) is the study of the faults that may appear in these systems. This paper starts with a historical review of the Four Three-Phase Symmetrical Components Technique, which was proposed for analyzing the faults that could occur on 12-phase power systems. Then a detailed study of transverse short-circuit faults that could occur on such systems is given in terms of this technique.

Fault Analysis of Six Phase Power System Using Six Phase Symmetrical Components

The use of six–phase for power transmission was investigated and tested as an alternative to three phase transmission. High phase order (HPO) transmission systems are those designed to transmit more than three phases of electrical power, normally six phases. A few studies had encountered the fault analysis of the six–phase system with the six symmetrical voltage and currents. In this article, the method of symmetrical components is used to analyze the 23 significant fault types that can occur on the six–phase transmission line with the six symmetrical voltage and current components encountered.

Electrostatic and environmental analyses of high phase order transmission lines

Abstract This paper presents an electrostatic modeling and environmental effect analysis of the high phase order transmission lines (HPOTL) using the charge simulation method. Both the conversion of the existing EHV and UHV double circuit transmission lines to six-phase lines, and the use of new, compact circular configuration HPOTL are introduced and discussed in the light of electric field computation at both the subconductor/conductor surface and the ground level. A new technique is also presented to decrease drastically the electric field at the ground level with a negligible increase in the conductor surface gradient and the charging current of the bottom phases. In this technique, a very few number of extra ground wires under each circuit are added, where they can also be utilized as optical ground wires for telecommunication purposes. Different phase arrangements, voltage ratings and conductor coating of the above-mentioned two cases are studied to investigate the possibilities of increasing the power handling capabilities without augmenting the environmental effects. It seems that HPOTL give a promising cost-effective means for increasing the power handling capability either for the existing double circuit transmission lines by 73% via increasing the operating voltage, or for the compact HPOTL via using six or more phases.

Magnetic field of high-phase order and compact transmission lines

Research has been conducted in high phase order (HPO) power transmission wherein 6 or 12 phases are used to transmit power in less physical space and with reduced environmental effects than conventional designs. In this paper, existing 3-phase double circuit transmission lines (TL) are reconfigured to 6-phase systems for the purpose of calculating and comparing the magnetic field of both systems. The magnetic field of several single-phase configurations; flat, vertical, delta and inverted-delta with the same degree of compaction is calculated and analysed at 1m height above the ground level. The magnetic field of the inverted-delta arrangement, which showed the lowest field profile, is compared with the magnetic field of 6- and 12-phase TLs having the same degree of line compaction and current loading conditions. The three systems are analysed when their lowest conductors had the same clearance to ground in one case and when their highest conductor positions were matched in another case. A comparison between 12-, 6- and 3-phase double circuit TLs having the same degree of compaction, the same phase voltage, the same clearance to ground and the same current per conductor is made to demonstrate if HPO lines reduce fields or not. The 6- and 12-phase lines are raised while keeping their conductors within the space, which would be taken by the conductors of the double circuit line. In this case, the highest conductor positions of the two systems are matched and the magnetic field is recomputed to conclude the results. The vector magnetic field potential concept, as extended to HPO transmission lines, together with a flexible developed computer program are used to calculate and present the magnetic flux density components profiles around the mentioned systems. Copyright © 2002 John Wiley & Sons, Ltd.

Analysis of faulted power systems by phase coordinates

This paper presents a method for the calculation of faulted power systems using phase coordinates. The method is more efficient and easier to program than the classical symmetrical components based fault analysis methods. Furthermore, it allows the study of any complex fault conditions and the inclusion of multi-phase components such as high phase order transmission lines.

The Analysis of Sequential ground Faults on a Six Phase Generator in Phase Co-ordinates.(Dept.E)

Transmission of bulk power over high phase order transmission lines KPOT, is being considered as a potential alternative to the conventional three phase lines. Lo practical, six phase systems appear to be favored. Should HPOT prove to be economically and technically viable, the problem of fault analysis, in particular the analysis of sequential faults on HPOT system appears to be a complicated one. When a ground fault on power system involves more than one terminal, tire fault usually develops in sequence. This paper presents a generalized treatment of sequential ground faults on the terminal of an initially unloaded six phase symmetrical generator. No restriction is placed either on the sequence in which the ground fault develops or on Tie instants at which the various phases are grounded. Expressions for transient phase currents and transient terminal voltages have been given. An expression for the neutral current which is an important variable for any protection scheme bas also been given. The method given in the paper can be applied to a power system of any number of phases by suitably adjusting the summation index in general equations. The analysis has been done in actual phase variable. Finally, the results for an arbitrary sequential ground fault on the terminals of a fictitious six phase generator have been given.

An investigation into loadability characteristics of EHV high phase order transmission lines

This paper deals with construction and investigation of loadability characteristics of high phase order (HPO) transmission lines extending the analytical concepts developed over the years for three-phase power systems. An assessment of the benefits of HPO lines in terms of their loadability as constrained by several power system performance and operating environment criteria is made with regard to their lower phase order counterparts. In addition, loadability dependence of HPO transmission lines on VAr supply is studied. The results of the present work should be useful in transmission planning and circuit uprating, particularly with a HPO option in view. >

Protecting NYSEG's six-phase transmission line

The high phase order transmission demonstration project is described. An existing 115 kV double-circuit transmission line was electrically reconfigured into a single-circuit, six-phase transmission line for this purpose. A description is given for different computer applications used in all stages of design, operation, and postoperation analysis. The complex multirelay microprocessor-based protection system is discussed. The multirelay microprocessor protection system was tested for many typical fault combinations using a computer controlled fault simulator. Currents and voltages were calculated using the Electromagnetic Transient Program (EMTP).< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

The analysis of random sequential ground faults on a high phase order (six-phase) power system in phase coordinates

High phase order transmission (HPOT) lines are considered a potential alternative to the conventional three-phase lines for the transmission of bulk power. In particular, six- and twelve-phase systems appear to be favoured for this purpose. Should HOPT prove to be economically and technically viable, the problem of fault analysis, in particular the analysis of random sequential ground faults on these systems, appears to be a complicated one. When a ground fault on a power system involves more than one terminal, the fault usually develops in sequence. This paper presents a generalized analysis of random sequential ground faults on the terminals of an initially unloaded six-phase symmetrical generator. No restriction is placed either on the sequence in which the ground fault develops or on the instants at which the various phases are grounded. Single equations from which all transient phase currents and transient terminal voltages can be calculated are given. An expression for the transient neutral current which is an important variable for any protection scheme against ground faults is also given. The method in this paper can be applied to a power system of any number of phases by suitably adjusting the summation indices in the general equations. The analysis has been done in actual phase variables. Finally, the results for an arbitrary sequential ground fault on the terminals of a fictitious six-phase generator are given.

A New Generalized Approach to Fault Analysis of High Phase Order Transmission Systems

ABSTRACT High phase-order power transmission lines are being considered by power system engineers as one of the alternatives for augmenting the power transfer capability of existing power corridors. For the practical realisation of such high phase-order transmission lines, fault analysis constitutes one of the important planning studies. In this work, a new, generalized and comprehensive approach is presented to carry out the fault analysis of power transmission systems of any phase-order and under any type of transposition. The procedure is applicable to both earth faults and phase faults and all the desired results can be easily obtained by means of the computer programme specially developed for this purpose. Its flexibility has been demonstrated by application to a sample power system. Also, the discrepancies In the fault analysis procedure of a six phase transmission system reported In an earlier publication have been clearly brought out.

Application of Levinson algorithm for fault calculations in high phase order transmission systems

Ever increasing pressures against the construction of new high voltage transmission lines are forcing electric utilities to seek new ways of augmenting the power transmission capabilities of existing rights-of-way. One of the alternatives being contemplated is high phase order transmission, where the number of phases is raised from three to six, twelve or higher. In order to make full utilization of the idea, transmission line design with the phase conductors being located on the circumference of a circle is advocated. The primitive impedance matrix of such a configuration of phase conductors is a Toeplitz matrix and is also symmetric. A generalized approach based on the application of Levinson algorithm is developed in the present paper for the calculation of fault currents in an arbitrary N-phase transmission line. The fault currents due to faults involving any number of phases to ground are calculated using the algorithm. Results for six and twelve phase systems obtained using the method are included in the paper.

Economics of EHV High Phase Order Transmission

The economics of high phase order transmission (six or twelve phase lines) are compared to UHV three phase. The comparisons are developed from optimized line designs, based on realistic lifetime costs. Detailed structure designs were used in the study, with terminal equipment costs included to develop- a breakeven distance beyond which savings in the HPO transmission line offset any increased substation costs. This breakeven distance is typically only a few miles, i. e. much shorter than projected UHV lines. A sensitivity analysis allows the general conclusion to be drawn that high phase order is econocmically compettivei- with UHV. Additional advantages are that the HPO structures are significantly smaller, and the ROW probably significantly narrower.

Economics of EHV High Phase Order Transmission

Economics of EHV High Phase Order Transmission

Prediction of the Optimum Coupling for PLC Propagation on Double Circuit and High Phase Order Transmission Lines

Prediction of the Optimum Coupling for PLC Propagation on Double Circuit and High Phase Order Transmission Lines

High Phase Order Transmission--A Feasibility Analysis Part II--Overvoltages and Insulation Requirements

High phase order transmission (HPO), the use of more than the conventional three phases, is a unique approach to more efficiently using the overhead transmission rights-of-way. This paper evaluates those areas which impact phase clearances and insulation requirements. Fault overvoltages, overvoltagees due to interphase coupling, switching surges, rate of rise of circuit breaker recovery voltage, and lightning performance are analyzed. Additionally, the effects of wind, ice, fault currents, and phase spacer performance on conductor spacing are considered. Representative conductor spacings and terminal insulation levels are tabulated based on the foregoing analyses.

High Phase Order Transmission--A Feasibility Analysis Part I--Steady State Considerations

High phase order transmission (HPO), the use of more than the conventional three phases, is a unique approach to more efficiently using the overhead transmission rights-of-way. This paper addresses definition of system voltage nomenclature; steady state system operation as affected by transmission line impedances; line and generator current unbalance; and the electrical environmental aspects of radio noise, audible noise, and electric fields at ground level. Quantitative results for these areas are compared to representative 3-phase conditions.