en08000358.vsd
IEC08000358 V1 EN
Figure 201:
Short-time unbalanced current capability of direct cooled generators
Continuous I
2
- capability of generators is also covered by the standard. Table
below (from ANSI standard C50.13) contains the suggested capability:
Table 44:
Continous I
2
capability
Type of generator
Permissible I
2
(in percent of rated
generator current)
Salient Pole:
with damper winding
10
without damper winding
5
Cylindrical Rotor
Indirectly cooled
10
Directly cooled
to 960 MVA
8
961 to 1200 MVA
6
1201 to 1500 MVA
5
As it is described in the table above that the continuous negative sequence current
capability of the generator is in range of 5% to 10% of the rated generator current.
During an open conductor or open generator breaker pole condition, the negative
sequence current can be in the range of 10% to 30% of the rated generator current.
Other generator or system protections will not usually detect this condition and the
only protection is the negative sequence overcurrent protection.
Negative sequence currents in a generator may be caused by:
•
Unbalanced loads such as
•
Single phase railroad load
•
Unbalanced system faults such as
Section 9
1MRK 502 071-UEN -
Current protection
390
Generator protection REG670 2.2 IEC and Injection equipment REX060, REX061, REX062
Application manual
Содержание Relion REG670
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