scope:

Foreword

This standard defines elements and commonly used components in excitation systems and contains definitions for excitation systems applied to synchronous machines, for general requirements of a synchronous machine refer to ANSI C50.10-1977.

A synchronous machine excitation control system operating under automatic control is a feedback control system. Thus, the working group Terminology of the Excitation Subcommittee of the Power Generation Committee adopted definitions that had common basis to excitation systems. Efforts were made not to conflict terms found in ANSI/IEEE Std 100-1984 , IEEE Standard Dictionary of Electrical and Electronics Terms, but to clarify or more fully define terms as related specifically to excitation of synchronous machines.

The task of the working group can be divided into two areas:

1) To gather all the existing definitions applicable to the field of excitation systems, and from these definitions to extract those definitions of value.

2) To formulate new definitions where these are needed.

Three definitions to classify exciters are now established:

1) dc generator - commutator exciter

2) alternator - rectifier exciter

3) static - rectifier exciter

It is thought that these types of exciters cover most if not all of the types used in modern excitation systems for large synchronous machines. The commutator exciter can have a continuous or noncontinuous acting regulator, and the rectifier exciter can have controlled or noncontrolled rectifiers.

This standard would also like to draw particular attention to three other recent excitation system documents:

1) ANSI/IEEE Std 421A-1978 ¹. This guide presents dynamic performance criteria, definitions and test procedures for excitation control systems as applied by electric utilities.

2) ANSI/IEEE Std 421B-1979 ¹. This standard applies to high-potential testing of complete excitation systems and their components for synchronous machines.

3) IEEE Committee Report, Excitation System Models for Power System Stability Studies. This paper presents excitation system models suitable for use in large-scale system stability studies. With these models, most of the excitation systems currently in widespread use on large, system-connected generators in North America can be represented. This paper replaces a similar committee report dated 1968.

IEEE Std 421-1972 was a definitions standard that is referenced in many other IEEE standards, papers, committee reports, etcetera. The changes being made in this revision do not invalidate any standard, paper, report, etcetera, that used IEEE Std 421-1972 as a reference document.

Previous definitions which included a phrase response ratio have been deleted. Only a single definition, excitation system nominal response, encompassing the overall performance of the excitation system is presented. Unique conditions for various excitation systems as related to this performance parameter are identified.

This revision has deleted a few basic terms, such as amplifier, drift, error, and input signal. These terms are taken care of in the IEEE Standard Dictionary. A few additional terms have been added. Table 1 of this revision shows a detailed correlation between the various excitation systems and the appropriate computer model type as described in the IEEE committee report on computer modeling of excitation systems.

Members of the Working Group of the Excitation Systems Subcommittee of the Power Generation Committee of the IEEE Power Engineering Society, which formulated the 1972 standard, were as follows:

P. O. Bobo , Chair

R. R. Bast

M. L. Crenshaw

A. C. Dolbec

K. R. McClymont

F. W. Keay

F. R. Schleif

J. W. Skooglund

G. I. Stillman

Michael Temoshok

R. H. Waltman

H. S Wilson

Others contributing to the work of the group were:

J. R. Mather

P. R. Landrieu

A. S. Rubenstein

Members of the Working Group of the Excitation Systems Subcommittee of the Power Generation Committee of the IEEE Power Engineering Society, which revised this standard, are:

J. R. Michalec , Chair

M. L. Crenshaw

K. J. Dhir

D. I. Gorden

H. Jaleeli

F. W. Keay

D. C. Lee

J. R. Mather

G. R. Meloy

D. H. Miller

J. O. Nichols

D. G. Ramey

J. W. Thomas

I. Trebincevic

R. H. Waltman

T. R. Whittemore

The following persons were on the balloting committee that approved this document for submission to the IEEE Standards Board:

W. W. Avril

M. S. Baldwin

G. G. Boyle

F. L. Brennan

P. G. Brown

H. E. Church, Jr

R. S. Coleman

E. A. Cooper

R. E. Cotta

M. L. Crenshaw

P. M. Davidson

G. R. Engmann

W. M. Fenner

A. H. Ferber

D. I. Gorden

R. D. Handel

M. E. Jackowski

P. R. Landrieu

G. Luri

O. S. Mazzoni

M. W. Migliaro

J. L. Mills

P. A. Nevins

S. Nikolakakos

J. T. Nikolas

M. I. Olken

R. J. Reiman

D. E. Roberts

W. J. Rom

M. N. Sprouse

A. J. Spurgin

J. E. Stoner, Jr

J. B. Sullivan

S. Tjepkema

R. H. Waltman

T. Whittemore

C. J. Wylie

T. D. Youkins

D. Diamant

G. Berman

A. H. Foss

Scope

This standard defines elements and commonly used components in excitation control systems and contains definitions for excitation systems as applied to synchronous machines. The primary purpose is to provide a vocabulary for

1) Writing excitation systems specifications

2) Evaluating excitation system performance

3) Specifying methods for excitation system tests

4) Preparing excitation system standards

5) Serving as an educational means for those becoming acquainted with excitation systems