Document: NUREG-0800
Document ID: 853719df-a6ea-408b-8d43-5956155abc38
Document Type: srp
Title: and 8.3.2.
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML1007/ML100740246.pdf
Revision Date: 2023-06
Chapter: 8
Section ID: 8.3.1
CFR Part: 
CFR Title: 

Content:
determine the ability of the generator circuit breaker to switch load current up to the rated continuous current of the generator, such as load currents that may be encountered in normal service. When switching the generator from the system, both generator circuit breaker terminals remain energized. The power frequency recovery voltage appearing across the generator circuit breaker is equal to the sum of voltage drops on the reactances of the generator and transformer and the corresponding short-circuit reactance of the high-voltage system. For applications which use only one generator circuit breaker, the circuit breaker should be cycled through 40 load interruption operations (a lesser number requires suitable justification) at a current equal to the normal full load continuous current rating of the circuit breaker. For applications which utilize two generator circuit breakers in a parallel circuit, the circuit breaker should be given 40 load interruption operations (a lesser number requires suitable justification) at a current equal to twice the normal full load continuous current rating of the circuit breakers. The procedures and acceptance criteria utilized for this test should be based upon those given in IEEE Std C37.013. (iii) Short Circuit Current Rating. The rated short-circuit current is demonstrated by a series of symmetrical and asymmetrical tests, and close-open tests described in the standard. The rated symmetrical current shall be the rated current value with the power frequency voltage associated with the rated maximum voltage and with a rated inherent transient recovery voltage as described in IEEE Std C37.013 for system- source faults and generator-source faults. The rated asymmetrical current-interrupting capability is demonstrated within the same conditions as the symmetrical current. 8.2-34 Revision 5 - May 2010 The circuit breaker should have, as a minimum, the capability of interrupting the maximum asymmetrical and symmetrical fault current