
8.4
Overexcitation protection OEXPVPH (24)
Function description
IEC 61850
identification
IEC 60617
identification
ANSI/IEEE C37.2
device number
Overexcitation protection
OEXPVPH
U/f >
SYMBOL-Q V1 EN
24
8.4.1
Introduction
When the laminated core of a power transformer or generator is subjected to a
magnetic flux density beyond its design limits, stray flux will flow into non-laminated
components not designed to carry flux and cause eddy currents to flow. The eddy
currents can cause excessive heating and severe damage to insulation and adjacent
parts in a relatively short time. The function has settable inverse operating curves and
independent alarm stages.
8.4.2
Principle of operation
The importance of Overexcitation protection (OEXPVPH, 24) function is growing as
the power transformers as well as other power system elements today operate most of
the time near their designated limits.
Modern design transformers are more sensitive to overexcitation than earlier types.
This is a result of the more efficient designs and designs which rely on the
improvement in the uniformity of the excitation level of modern systems. Thus, if
emergency that causes overexcitation does occur, transformers may be damaged unless
corrective action is promptly taken. Transformer manufacturers recommend an
overexcitation protection as a part of the transformer protection system.
Overexcitation results from excessive applied voltage, possibly in combination with
below-normal frequency. Such condition may occur when a transformer unit is on load,
but are more likely to arise when it is on open circuit, or at a loss of load occurrence.
Transformers directly connected to generators are in particular danger to experience
overexcitation condition. It follows from the fundamental transformer equation, see
equation
, that peak flux density Bmax is directly proportional to induced voltage
E, and inversely proportional to frequency f, and turns n.
E
.
f n Bmax A
4 44
=
× × ×
×
EQUATION898 V2 EN
(Equation 135)
1MRK505222-UUS C
Section 8
Voltage protection
529
Technical reference manual
Содержание Relion 670 series
Страница 1: ...Relion 670 series Line differential protection RED670 ANSI Technical reference manual...
Страница 2: ......
Страница 40: ...34...
Страница 50: ...44...
Страница 60: ...54...
Страница 126: ...120...
Страница 384: ...378...
Страница 496: ...490...
Страница 556: ...550...
Страница 602: ...596...
Страница 620: ...614...
Страница 794: ...788...
Страница 864: ...858...
Страница 988: ...982...
Страница 998: ...992...
Страница 1084: ...1078...
Страница 1164: ...1158...
Страница 1168: ...1162...
Страница 1170: ...1MRK002802 AB 1 670 1 2 PG ANSI V1 EN Section 21 1MRK505222 UUS C Connection diagrams 1164 Technical reference manual...
Страница 1171: ...1MRK002802 AB 2 670 1 2 PG ANSI V1 EN 1MRK505222 UUS C Section 21 Connection diagrams 1165 Technical reference manual...
Страница 1172: ...1MRK002802 AB 3 670 1 2 PG ANSI V1 EN Section 21 1MRK505222 UUS C Connection diagrams 1166 Technical reference manual...
Страница 1173: ...1MRK002802 AB 4 670 1 2 PG ANSI V1 EN 1MRK505222 UUS C Section 21 Connection diagrams 1167 Technical reference manual...
Страница 1174: ...1MRK002802 AB 5 670 1 2 ANSI V1 EN Section 21 1MRK505222 UUS C Connection diagrams 1168 Technical reference manual...
Страница 1175: ...1MRK002802 AB 6 670 1 2 ANSI V1 EN 1MRK505222 UUS C Section 21 Connection diagrams 1169 Technical reference manual...
Страница 1176: ...1MRK002802 AB 7 670 1 2 ANSI V1 EN Section 21 1MRK505222 UUS C Connection diagrams 1170 Technical reference manual...
Страница 1177: ...1MRK002802 AB 8 670 1 2 ANSI V1 EN 1MRK505222 UUS C Section 21 Connection diagrams 1171 Technical reference manual...
Страница 1178: ...1MRK002802 AB 9 670 1 2 ANSI V1 EN Section 21 1MRK505222 UUS C Connection diagrams 1172 Technical reference manual...
Страница 1179: ...1MRK002802 AB 10 670 1 2 ANSI V1 EN 1MRK505222 UUS C Section 21 Connection diagrams 1173 Technical reference manual...
Страница 1180: ...1MRK002802 AB 11 670 1 2 ANSI V1 EN Section 21 1MRK505222 UUS C Connection diagrams 1174 Technical reference manual...
Страница 1181: ...1MRK002802 AB 12 670 1 2 ANSI V1 EN 1MRK505222 UUS C Section 21 Connection diagrams 1175 Technical reference manual...
Страница 1182: ...1MRK002802 AB 13 670 1 2 ANSI V1 EN Section 21 1MRK505222 UUS C Connection diagrams 1176 Technical reference manual...
Страница 1183: ...1MRK002802 AB 14 670 1 2 ANSI V1 EN 1MRK505222 UUS C Section 21 Connection diagrams 1177 Technical reference manual...
Страница 1184: ...1MRK002802 AB 15 670 1 2 ANSI V1 EN Section 21 1MRK505222 UUS C Connection diagrams 1178 Technical reference manual...
Страница 1220: ...1214...
Страница 1230: ...1224...
Страница 1231: ...1225...