IEEE C37.119-2005 pdf free

IEEE C37.119-2005 pdf free.IEEE Guide for Breaker Failure Protection of Power Circuit Breakers.
3.2.5 local breaker failure protection: A backup protection system that is in the same substation as the primary protection, so it does not suffer from the disadvantages of the remote backup protection. I lowever. it may use some of the same equipment. such as transducers, batteries. and circuit breakers as the primary protection and can therefore fail to operate for the same reasons as the primary protection.
3.2.6 primary protection: The main protection system for a given zone of protection that operates in the fastest time and removes the least amount of equipment from service.
3.2.7 remote backup protection: Historically, the first set of backup protection that was installed. It is completely independent of the relays, transduccrs. batteries, and circuit breakers of the primary protection system it is backing up by virtue of its physical location. Its advantage is that there are no common-mode failures that can affect both systems of protection, Its disadvantage is thc fact that remote protection may remove more system elements than is desirable or necessary to clear a fault. Additionally, as the power system matured, it became increasingly difficult for remote protection to detect (see) all the faults that the primary protection could detect.
It must be recognized that these definitions are only intended to facilitate communication so that there is general understanding of the subject under discussion. They are not to be rigidly applied as if they constituted design specifications. Protection systems are designed in accordance with accepted engineering pnncipIes involving reliability (dependability and security), selectivity, and coordination. The definitions when applied to individual elements, or to the total protection system, are for specific applications and may vary with the application. For instance, in a substation without a pilot protection system, time-delay overcurrent or zone 2 relays are the primary protection for faults in the last 10% 20% of the line but are the remote backup protection for the adjoining bus and line section. When a pilot scheme is installed, the time-delay overcurrent and zone 2 relays are then referred to as local backup for the end-of-line faults and remote backup for the adjoining bus and line section.
4. The need for breaker failure protection
(‘ircuit breakers are strategically located in power systems to connect circuits and electrical apparatus. (‘ircuit breakers are commanded to open and close by protection and control systems that monitor conditions on the power system. Protective relay systems detect abnomial conditions, most notably, system faults (short circuits). and direct one or more circuit breakers to open to isolate the faulted circuit or equipment. Protection systems are coordinated so that the circuit breaker(s) nearest the fault are opened to intemipt. or clear,the fault with minimum impact to the remainder of the power system. This critical operation requires that the circuit breaker interrupt, or clear, fault curent.IEEE C37.119 pdf free download.