Petersen Coils Research Articles

Further contribution to the discussion on “Line protection by Petersen coils, with special reference to conditions prevailing in Great Britain”

Further contribution to the discussion on “Line protection by Petersen coils, with special reference to conditions prevailing in Great Britain”

Discussion on “Line protection by Petersen coils, with special reference to conditions prevailing in Great Britain” before the Scottish Centre, at Edinburgh, 25th October, 1938

Discussion on “Line protection by Petersen coils, with special reference to conditions prevailing in Great Britain” before the Scottish Centre, at Edinburgh, 25th October, 1938

The authors' reply to the discussions on “Line protection by Petersen coils, with special reference to conditions prevailing in Great Britain”

The authors' reply to the discussions on “Line protection by Petersen coils, with special reference to conditions prevailing in Great Britain”

The Electrostatic Unbalance of Transmission Lines and Its Effect on the Application of Petersen Coils

RECENTLY three Petersen coils were installed on the 66-kv transmission system of the Metropolitan Edison Company of Pennsylvania. These Petersen coils provide service protection to approximately 320 miles of overhead transmission lines against outages and voltage dips which would otherwise result when single phase-to-ground flashovers occur on the system. Much of the 66-kv transmission system consists of two-circuit lines with vertical configurations of the line conductors with no transpositions prior to the Petersen-coil installation.

The electrostatic unbalance of transmission lines and its effect on the application of Petersen coils

RECENTLY three Petersen coils were installed on the 66-kv transmission system of the Metropolitan Edison Company of Pennsylvania. These Petersen coils provide service protection to approximately 320 miles of overhead transmission lines against outages and voltage dips which would otherwise result when single phase-to-ground flashovers occur on the system. Much of the 66-kv transmission system consists of two-circuit lines with vertical configurations of the line conductors with no transpositions prior to the Petersen-coil installation.

Transactions: Papers and discussions comprising pages 663–712 of the 1938 volume: System analysis for Petersen-coil application

Careful analysis of the characteristics of a power system has been found to be necessary before applying Petersen coils to a system which has been operating either with the neutral isolated or grounded. In these two companion papers on Petersen coils, accent has been placed on the analysis of system characteristics in order to determine whether or not the application of Petersen coils will be satisfactory.

System Anaysis for Petersen-Coil Application

Careful analysis of the characteristics of a power system has been found to be necessary before applying Petersen coils to a system which has been operating either with the neutral isolated or grounded. In these two companion papers on Petersen coils, accent has been placed on the analysis of system characteristics in order to determine whether or not the application of Petersen coils will be satisfactory. In this paper (part I) the general features of Petersen-coil application are considered, and the fundamentals of calculating coil characteristics are given. In the companion paper (part II) by F. Von Voigtlander, the methods of performing detailed calculations on system fault currents, coil ratings, and voltages are given in an illustrative example, together with field tests to check design computations and performance of the equipment.

The authors' reply to the discussions on “Line protection by Petersen coils, with special reference to conditions prevailing in Great Britain” at Leeds, Chester, Newcastle and Cardiff

The authors' reply to the discussions on “Line protection by Petersen coils, with special reference to conditions prevailing in Great Britain” at Leeds, Chester, Newcastle and Cardiff

Discussion on “Line protection by Petersen coils, with special reference to conditions prevailing in Great Britain” before the Western Centre, at Cardiff, 25th April, 1938

Discussion on “Line protection by Petersen coils, with special reference to conditions prevailing in Great Britain” before the Western Centre, at Cardiff, 25th April, 1938

Discussion on “Line protection by Petersen coils, with special reference to conditions prevailing in Great Britain” before the Mersey and North Wales (Liverpool) Centre, at Chester, 22nd February, 1938

Discussion on “Line protection by Petersen coils, with special reference to conditions prevailing in Great Britain” before the Mersey and North Wales (Liverpool) Centre, at Chester, 22nd February, 1938

Discussion on “Line protection by Petersen coils, with special reference to conditions prevailing in Great Britain” before the North Midland Centre, at Leeds, 1st February, 1938

Discussion on “Line protection by Petersen coils, with special reference to conditions prevailing in Great Britain” before the North Midland Centre, at Leeds, 1st February, 1938

Discussion on “Line protection by Petersen coils, with special reference to conditions prevailing in Great Britain” before the North-Eastern Centre, at Newcastle, 28th February, 1938

Discussion on “Line protection by Petersen coils, with special reference to conditions prevailing in Great Britain” before the North-Eastern Centre, at Newcastle, 28th February, 1938

Some engineering features of Petersen coils and their application

Discussion and author's closure of a paper by E. M. Hunter published on pages 11–18 of this volume (January section), and presented for oral discussion at the lightning protection section of the winter convention, New York, N. Y., January 25, 1938.

Line protection by Petersen coils, with special reference to conditions prevailing in Great Britain

The object of this paper is to stimulate interest in a piece of apparatus which, until comparatively recently, was practically unknown in this country. Its efficacy in preventing interruptions of supply under certain types of fault conditions has been for many years fully appreciated on the Continent, where even on underground networks it is regarded as indispensable by many supply authorities.Although the principles involved are briefly referred to for the benefit of those who are not familiar with the publications available dealing with the fundamental theory, the matter is dealt with from an operating rather than a theoretical point of view by drawing attention to a number of problems, many of them peculiar to this country, which arise when a Petersen coil is to be applied on a system originally intended to operate with the neutral solidly earthed; by suggesting convenient ways to obtain the information required by the makers for a coil or coils to suit any particular network; by dealing with a number of cases in which special measures are necessary; by explaining the means of tuning the coil to suit changing network conditions; by giving results obtained from coils in operation; and by comparing these results with those of solid or resistance earthing.

Discussion on “Line protection by Petersen coils, with special reference to conditions prevailing in Great Britain” before the Transmission Section, 15th December, 1937

Discussion on “Line protection by Petersen coils, with special reference to conditions prevailing in Great Britain” before the Transmission Section, 15th December, 1937

Petersen coils discussed at lightning session

Petersen coils discussed at lightning session

Some engineering features of Petersen coils and their application

THE TUNED-REACTANCE method of grounding a system neutral was first disclosed by Professor W. Petersen of Germany in 1917 (German patent number 304,823). It has been used extensively in Europe and other parts of the world and the number of installations in the United States recently has been increasing rapidly, which suggests that there is a place for the Petersen coil in American grounding practice. Tracing briefly the installations of Petersen coils in this country, the first one was made in a 44-kv system in 1921. Operating records on this system showed that the Petersen coil had improved service considerably. A second installation of 2 coils was made in a 140-kv system in 1931. Again expected improvements in service were substantiated. Further installations were made in 33-kv systems in 1935 and 1936. Although favorable reports on service continuity were given on all these installations, up until 1937, a period of approximately fifteen years, only a total of five coils were installed in systems in the United States. During the same period approximately 1,700 Petersen coils were installed in systems in other parts of the world.

Some Engineering Features of Petersen Coils and Their Application

THE TUNED-REACTANCE method of grounding a system neutral was first disclosed by Professor W. Petersen of Germany in 1917 (German patent number 304,823). It has been used extensively in Europe and other parts of the world and the number of installations in the United States recently has been increasing rapidly, which suggests that there is a place for the Petersen coil in American grounding practice. Tracing briefly the installations of Petersen coils in this country, the first one was made in a 44-kv system in 1921. Operating records on this system showed that the Petersen coil had improved service considerably. A second installation of 2 coils was made in a 140-kv system in 1931. Again expected improvements in service were substantiated. Further installations were made in 33-kv systems in 1935 and 1936. Although favorable reports on service continuity were given on all these installations, up until 1937, a period of approximately fifteen years, only a total of five coils were installed in systems in the United States. During the same period approximately 1,700 Petersen coils were installed in systems in other parts of the world.

Lightning

The first part of this paper deals with lightning as a physical phenomenon. The formation of thunderclouds is associated with convectional instability of the atmosphere, the separation of charge being effected by the resulting upward currents of air. Lightning strokes usually discharge negative electricity into the ground and consist of a preliminary “leader” stroke from cloud to ground followed by a powerful “return” stroke from ground to cloud. A complete flash usually consists of a sequence of such double strokes separated by time-intervals of the order of 10−2 sec. The distribution of flashes to earth under a storm centre is influenced by the distribution of space charge above the ground and by discontinuities of conductivity in the ground itself.The second part of the paper deals with the effects of lightning strokes to overhead transmission lines. It is concluded that direct strokes to line conductors are certain to cause flashover: interruption to supply may be minimized either by devices to clear such faults (Petersen coils, expulsion protective gaps), or by overhead earth wires, which will preventany strokes falling on the line conductors. Strokes to towers and earth wires are unlikely to cause flashover of a line insulated with 9 standard cap-and-pin units, if tower footing resistances are below 10 ohms; footing resistances low enough to prevent flashover with only 3 cap-and-pin units may be impossible to obtain.

Neutral inversion in power systems

A neutral displacement due to abnormal system conditions (other than short-circuits) is known by the name of “neutral in version”. This can occur as a result of open circuits in one or more phases of systems possessing inductance and capacitance, or owing to special conditions of neutral earth connections.A general formula is developed for the position of the neutral point on any system of any number of phases, balanced or unbalanced. This is then applied to deduce the neutral displacements occurring as a result of open circuits on systems fitted with neutral-earthing transformers and Petersen coils or arcing-earth suppressors.The possibility of neutral inversion on certain types of balanced system, even without open circuits, is demonstrated and a qualitative consideration of the phenomena is given.Finally, instances are mentioned of neutral inversion which has occurred in practice, and remedies are indicated, together with a summary of system arrangements to be avoided in design.