Cooling - ABB REG650 Technical Manual

1MRK 502 034-UEN -
8.4.7.3
Technical Manual
IEEE OVEREXCITATION CURVES
Time (s)
1000
100
10
1
1 2 3
IEC09000115 V1 EN
Figure 123: Delays inversely proportional to the square of the overexcitation
The critical value of excitation M is determined indirectly via OEXPVPH setting V/
Hz>>. V/Hz>> can be thought of as a no-load-rated-frequency voltage, where the
inverse law should be replaced by a short definite delay, tMin. If, for example, V/
Hz>> = 140 %, then M is according to equation 82.
( )
V Hz>> / f
= =
M 1.40
Ur/fr
IECEQUATION2286 V1 EN

Cooling

Overexcitation protection function (OEXPVPH) is basically a thermal protection;
therefore a cooling process has been introduced. Exponential cooling process is
4 5 10
OVEREXCITATION IN %
Section 8
Voltage protection
=
kForIEEE
60
kForIEEE =
20
=
kForIEEE
10
kForIEEE = 9
kForIEEE =
8
kForIEEE = 7
=
kForIEEE 6
=
kForIEEE 5
=
kForIEEE 4
=
kForIEEE 3
=
kForIEEE
2
= 1
kForIEEE
20 30 40
(M-Emaxcont)*100)
IEC09000115-1-en.vsd
(Equation 82)
243