Patent US5264778A successfully refreshed from Google Patents.
US5264778A
Expired / Lapsed
US
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Apparatus protecting a synchronous machine from under excitation
Assignee: Westinghouse Electric Corp
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Filing: 1991-12-31
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Granted: 1993-11-23
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Expires: 2011-12-31
Abstract
Abstract Apparatus for protecting a synchronous generator from under-excitation, includes a limiter implemented as part of a microprocessor based voltage regulator. The limiter selectively characterizes one or more limiting parameters, such as, system stability, machine capability and loss of field protection, as straight line segments in the real/reactive power plane to provide versatile, easily modified limits on excitation.
Inventors
- 👤 Donald S. Kimmel
- 👤 Charles R. Mummert
- 👤 Kenneth M. Eichler
- 👤 David R. Markus
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 19:41
CPC Classifications
H; H02; H02P; H02P9/00; H02P9/14; H02P9/26; H02P9/30; H02H; H02H7/00; H02H7/06; H02H7/065; Y; Y10; Y10S; Y10S174/00; Y10S174/13; Y10S174/14; Y10S174/17
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
85 words
Apparatus for controlling a synchronous machine connected to an electrical power grid, said apparatus comprising: a voltage regulator controlling excitation of said synchronous machine to regulate voltage on the machine and minimum excitation means including characterizing means characterizing as a function of real and reactive power a machine capability limit and a system stability limit, and means monitoring said excitation and applying to said voltage regulator a signal which increases excitation when said excitation is below either said stability limit or said machine capability limit.
Claim 2
Dependent Claim
85 words
Apparatus for controlling a synchronous machine connected to an electrical power grid, said apparatus comprising: a voltage regulator controlling excitation of said synchronous machine to regulate voltage on the machine and minimum excitation means including characterizing means characterizing as a function of real and reactive power a machine capability limit and a system stability limit, and means monitoring said excitation and applying to said voltage regulator a signal which increases excitation when said excitation is below either said stability limit or said machine capability limit.
Claim 3
Dependent Claim
119 words
Apparatus for controlling a synchronous machine connected to an electrical power grid, said apparatus comprising: a voltage regulator controlling excitation of said synchronous machine to regulate voltage on the machine and minimum excitation means including characterizing means characterizing as a function of real and reactive power a machine capability limit and a system stability limit, and means monitoring said excitation and applying to said voltage regulator a signal which increases excitation when said excitation is below either said stability limit or said machine capability limit, wherein said characterizing means characterizes said machine capability limit as at least one first line segment, and said system stability limit as at least one second line segment which intersects said first line segment.
Claim 4
Dependent Claim
119 words
Apparatus for controlling a synchronous machine connected to an electrical power grid, said apparatus comprising: a voltage regulator controlling excitation of said synchronous machine to regulate voltage on the machine and minimum excitation means including characterizing means characterizing as a function of real and reactive power a machine capability limit and a system stability limit, and means monitoring said excitation and applying to said voltage regulator a signal which increases excitation when said excitation is below either said stability limit or said machine capability limit, wherein said characterizing means characterizes said machine capability limit as at least one first line segment, and said system stability limit as at least one second line segment which intersects said first line segment.
Claim 5
Dependent Claim
109 words
Apparatus for controlling a synchronous machine connected to an electrical power grid, said apparatus comprising: a voltage regulator controlling excitation of said synchronous machine to regulate voltage on the machine; minimum excitation means including characterizing means characterizing as a function of real and reactive power a machine capability limit, and means monitoring said excitation and applying to said voltage regulator a signal which increases excitation when said excitation is below said machine capability limit; and means monitoring cooling effectiveness of said synchronous machine, and wherein said characterizing means includes means adjusting said characterizing of said machine capability limit in response to said means monitoring cooling effectiveness of said machine.
Claim 6
Dependent Claim
109 words
Apparatus for controlling a synchronous machine connected to an electrical power grid, said apparatus comprising: a voltage regulator controlling excitation of said synchronous machine to regulate voltage on the machine; minimum excitation means including characterizing means characterizing as a function of real and reactive power a machine capability limit, and means monitoring said excitation and applying to said voltage regulator a signal which increases excitation when said excitation is below said machine capability limit; and means monitoring cooling effectiveness of said synchronous machine, and wherein said characterizing means includes means adjusting said characterizing of said machine capability limit in response to said means monitoring cooling effectiveness of said machine.
Claim 7
Dependent Claim
133 words
Apparatus for controlling a synchronous machine connected to an electrical power grid, said apparatus comprising: a voltage regulator controlling excitation of said synchronous machine to regulate voltage on the machine; and minimum excitation means including digital processor means characterizing as a function of real and reactive power in at least one first straight line segment a minimum limit on said excitation, and means applying to said voltage regulator a limit signal which increases excitation when said excitation is below said minimum limit, wherein said processor means includes means characterizing a system stability limit on minimum excitation as at least one second straight line segment, and wherein said means applying to said voltage regulator a limit signal which increases excitation comprises means which increases excitation when said excitation is below said system stability limit.
Claim 8
Dependent Claim
133 words
Apparatus for controlling a synchronous machine connected to an electrical power grid, said apparatus comprising: a voltage regulator controlling excitation of said synchronous machine to regulate voltage on the machine; and minimum excitation means including digital processor means characterizing as a function of real and reactive power in at least one first straight line segment a minimum limit on said excitation, and means applying to said voltage regulator a limit signal which increases excitation when said excitation is below said minimum limit, wherein said processor means includes means characterizing a system stability limit on minimum excitation as at least one second straight line segment, and wherein said means applying to said voltage regulator a limit signal which increases excitation comprises means which increases excitation when said excitation is below said system stability limit.
Claim 9
Dependent Claim
133 words
Apparatus for controlling a synchronous machine connected to an electrical power grid, said apparatus comprising: a voltage regulator controlling excitation of said synchronous machine to regulate voltage on the machine; and minimum excitation means including digital processor means characterizing as a function of real and reactive power in at least one first straight line segment a minimum limit on said excitation, and means applying to said voltage regulator a limit signal which increases excitation when said excitation is below said minimum limit, wherein said processor means includes means characterizing a machine capability limit on minimum excitation as at least one second straight line segment, and wherein said means applying to said voltage regulator a limit signal which increases excitation comprises means which increases excitation when said excitation is below said machine capability limit.
Claim 10
Dependent Claim
133 words
Apparatus for controlling a synchronous machine connected to an electrical power grid, said apparatus comprising: a voltage regulator controlling excitation of said synchronous machine to regulate voltage on the machine; and minimum excitation means including digital processor means characterizing as a function of real and reactive power in at least one first straight line segment a minimum limit on said excitation, and means applying to said voltage regulator a limit signal which increases excitation when said excitation is below said minimum limit, wherein said processor means includes means characterizing a machine capability limit on minimum excitation as at least one second straight line segment, and wherein said means applying to said voltage regulator a limit signal which increases excitation comprises means which increases excitation when said excitation is below said machine capability limit.
Claim 11
Dependent Claim
145 words
Apparatus for controlling a synchronous machine connected to an electrical power grid, said apparatus comprising: a voltage regulator controlling excitation of said synchronous machine to regulate voltage on the machine; and minimum excitation means including digital processor means characterizing as a function of real and reactive power in at least one first straight line segment a minimum limit on said excitation, and means applying to said voltage regulator a limit signal which increases excitation when said excitation is below said minimum limit; wherein said processor means includes means characterizing a machine capability limit on minimum excitation as at least one second straight line segment which intersects said at least one first straight line segment; and cooling means monitoring cooling effectiveness of said synchronous machine and wherein said processor means includes means adjusting said characterizing of said machine capability limit in response to said cooling means.
Claim 12
Dependent Claim
145 words
Apparatus for controlling a synchronous machine connected to an electrical power grid, said apparatus comprising: a voltage regulator controlling excitation of said synchronous machine to regulate voltage on the machine; and minimum excitation means including digital processor means characterizing as a function of real and reactive power in at least one first straight line segment a minimum limit on said excitation, and means applying to said voltage regulator a limit signal which increases excitation when said excitation is below said minimum limit; wherein said processor means includes means characterizing a machine capability limit on minimum excitation as at least one second straight line segment which intersects said at least one first straight line segment; and cooling means monitoring cooling effectiveness of said synchronous machine and wherein said processor means includes means adjusting said characterizing of said machine capability limit in response to said cooling means.
Claim 13
Dependent Claim
97 words
Apparatus for controlling a synchronous machine connected to an electrical power grid, said apparatus comprising: a voltage regulator controlling excitation of said synchronous machine to regulate voltage on the machine; and minimum excitation means including digital processor means characterizing a loss of field limit on minimum excitation as a function of real and reactive power in at least one straight line segment which closely correlates with said trip function characteristic with a selected margin, and means applying to said voltage regulator a limit signal which increases excitation when said excitation is below said loss of field limit.
Claim 14
Dependent Claim
97 words
Apparatus for controlling a synchronous machine connected to an electrical power grid, said apparatus comprising: a voltage regulator controlling excitation of said synchronous machine to regulate voltage on the machine; and minimum excitation means including digital processor means characterizing a loss of field limit on minimum excitation as a function of real and reactive power in at least one straight line segment which closely correlates with said trip function characteristic with a selected margin, and means applying to said voltage regulator a limit signal which increases excitation when said excitation is below said loss of field limit.
References Cited (Backward Citations)
JPS5254111A
Cited
JPS5262612A
Cited
US4245182A
Cited
GB2037463A
Cited
SU892639A1
Cited
SU917296A1
Cited
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