Cooling - ABB REG650 Technical Manual

Section 9
Voltage protection
9.4.7.3
282
IEEE OVEREXCITATION CURVES
Time (s)
1000
100
10
1
1 2 3
IEC09000115 V1 EN
Figure 140: Delays inversely proportional to the square of the overexcitation
The critical value of excitation M is determined via OEXPVPH setting V/Hz>>. V/
Hz>> can be thought of as a no-load voltage at rated frequency, 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 91.
( )
V Hz>> / f
= =
M 1.40
Ur/fr
IECEQUATION2286 V1 EN

Cooling

The overexcitation protection function (OEXPVPH) is basically a thermal protection,
therefore a cooling process has been introduced. An exponential cooling process is
4 5 10
OVEREXCITATION IN %
1MRK 502 048-UEN A
kForIEEE =
60
=
kForIEEE
20
=
kForIEEE 10
= 9
kForIEEE
=
kForIEEE
8
= 7
kForIEEE
=
kForIEEE
6
=
kForIEEE
5
=
kForIEEE
4
=
kForIEEE
3
=
kForIEEE
2
= 1
kForIEEE
20 30 40
(M-Emaxcont)*100)
IEC09000115-1-en.vsd
(Equation 91)
Technical manual