IEEE Std C37.12 pdf free download

IEEE Std C37.12 pdf free download.Specifications of High- Voltage Circuit Breakers (over 1000 V).
4.4 Service conditions
4.4.1 Unusual and usual service conditions
Usual and unusual service conditions are described in IEEE Std C37.O4. The users should review IEEE
Std C37.O 10 for the unusual service conditions to determine if any apply to their system.
4.4.2 Seismic withstand
The circuit breaker should be suitable for application in a location subject to seismic disturbances, when specified. The user should specify the seismic conditions and acceptable response when the requirement is specified. The user should refer to IEEE Std 693TM [B5J, IEEE Std C37.81Th1 [815], or other appropriate standard to assist in defining the required seismic capability of the circuit breaker.9
4.5 Electrical characteristics
The electrical rating of the circuit breaker shall include rated continuous current, maximum operating voltage, rated interrupting current and time, rated impulse withstand, operating duty cycle, and the intended application of the circuit breaker. The specification should verify that all application duties as identified in IEEE Std C37.OlO, IEEE Std C37.Ol 1, IEEE Std C37.012 are described. Certain applications may require fast TRV capabilities or switching of shunt reactors; both of these are special applications and the user is referred to IEEE Std C37.06. ITM[H 10] and IEEE Std C37.015Th1 [B71 respectively for information on these topics.
In many cases, the ratings selected from preferred ratings tables of IEEE Std C37.06 will be adequate for the user’s application. The user will need to specify the circuit breaker rated current, rated voltage, rated short- circuit current, application, and the first-pole-to-clear factor only in the supplementary specification.
4.5.1 Performance
The circuit breaker shall meet all of its ratings as defined in IEEE Std C37.04 and as listed in IEEE Std C37.06 or specified by the purchaser.
NOTE—The ratings defined in IEEE Std C37.04 and as listed in IEEE Std C37.06 are suitable for the majority of high- voltage circuit breaker applications. I lowever, the referenced standards do not address all types of possible fault conditions, particularly three-phase line faults. Thorough consideration should be given to the ratings defined in the referenced standards and the application of the circuit breaker. Any application requirements that are not adequately addressed by the relirenced standards should be included in the specification and are subject to agreement between the manufacturer and user.
4.5.2 Out-of-phase withstand voltage
Users should be aware that IEEE Std C37.04- 1999 does not define an “out-of-phase” voltage withstand rating for the circuit breakers, and IEEE Std C37.09 does not have any test method to demonstrate this capability. The users may include the following statement for the circuit breaker to be used for synchronizing operations.
“The circuit breaker shall be capable of withstanding an out-of-phase voltage across the terminals with the phase angle between the two voltages continuously varying. The duration of out-of-phase voltage withstand shall be (xx).”
This requirement is to assure that the circuit breaker, in the open position is capable of withstanding voltages to which it can be subjected under such conditions as systems being out of phase. The duration for this condition should be specified by the user. The duration often minutes is usually sufficient. If out-of-phase conditions are expected to remain longer, it may be a better application solution to specify a circuit breaker having a higher rating. Users and the circuit breaker manufacturer should mutually agree on the circuit breakers out-of-phase voltage withstand and out-of-phase current interruption capability.IEEE Std C37.12 pdf download.