IEEE C37.11-1997 pdf download IEEE Standard Requirements for Electrical Control for AC High-Voltage Circuit Breakers Rated on a Symmetrical Current Basis
1.Overview
1.1 Scope
This standard applies to all types of electrically controlled ac high-voltage circuit breakers rated above 1000 V. Thisstandard applies for any type of power-operated mechanism and for both ac and dc control power. Only the basiccontrol elements of the circuit breaker, including reclosing where required, are included in this standard. This standarddoes not include devices or circuits for protective relaying, special interlocking, etc., since these are dependent uponthe specific application of a particular circuit breaker.
1.2 Purpose
The purpose of this standard is to establish basic requirements for ac high-voltage power circuit breaker controlschemes so that users and manufacturers can effect engineering and production economies by reducing the multiplicityof special control schemes that are specified in the absence of standards.
2. References
This standard shall be used in conjunction with the following publication. When a standard is superseded by anapproved revision, the revision shall apply.
IEEE Std C37.100-1992,EEE Standard Definitions for Power Switchgear (ANSI).
3. Functional requirements
The basic functional requirements of the control scheme for a circuit breaker include the following:
aThe circuit breaker mechanism shall make one complete closing operation, including automatic cutoff ofclosing power, after an initiating control device has operated and the first device in the control scheme hasresponded, even though the contacts of the initiating control device are opened before the circuit breakerclosing operation is completed.
NOTE -This requiremment ensures that, afler the closing operation has been initiated, a seal-in circuit will be provided.where necessary. so that the closing operation will be completed automatically, even though the operatorreleases the control switch before the circuit breaker is completely closed.
Some circuit breakers achieve complete closing by electromechanical means, even if the closing signal hasbeen removed before the closing operation is complete.
Control schemes in which the seal-in circuit or the equivalent is disconnected or made inoperative areobjectionable because of the hazard to circuit breaker performance.
There are some definite purpose circuit breakers, with mechanisms specially designed to be able to open andinterrupt safely, even during a closing operation, (i.e, before the circuit breaker has fully closed). Circuitbreakers of this type are not subject to this requirement.
Only one closing operation of the circuit breaker mechanism shall result from each close signal of anbinitiating control device, even though the circuit breaker trips while the initiating control device is still in theclosed position.
NOTE– This requirement ensures that the circuit breaker will not “pump ifit trips during a closing operation. The tripoperation may be due to a fault or a failure to latch.
1)The control scheme may allow reclosing in the event that control power is interrupted while the initiatingcontrol device remains closed, For example, reclosing is not disabled when the control circuit isintentionally opened and closed while checking for grounds.
2The control scheme should not allow reclosing in the event that control power is lost or reduced inyoltage as a result of the closing operation, while the initiating control device remains closed. A typicalexample is the case in which control power is obtained from the primary power system. When the circuitbreaker closes into a fault, the primary power system voltage is reduced, and subsequently the controlpower voltage is also reduced
NOTE — With maintained-contact type initiating devices. such as pressure switches. fluid-level switches. etc.lockout relays or other devices are necessary to prevent reclosure if control power is interrupted duringor subsequent to, a circuit breaker tripping operation while the initiating closing device remains closed
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When power is removed from the closing control circuit during or after an incomplete closing operation, allelectrically operated devices in the control circuit shall reset to the normal circuit breaker open position.except for those devices requiring a supply of control power in order for them to assume their normal circuitbreaker open position.
IEEE C37.11-1997 pdf download
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