IEEE 650-2017 pdf download
IEEE 650-2017 pdf download.IEEE Standard for Qualification of Class 1E Static Battery Chargers,lnverters, and Uninterruptible Power Supply Systems for Nuclear Power Generating Stations.
The replacement interval for limited-life components that cannot meet the desired equipment qualified life shall be equal to or less than their qualified life. The qualified life of a component may be extended after installation by additional testing, analysis, or operating experience. The specified replacement interval of a component shall be equal to or less than the interval established in the qualification process.
Components with significant aging mechanisms shall be aged in accordance with one or more of the following techniques, as applicable.
5.2.1 Natural aging
Components may be taken from a field installation that has been operating for the desired period designated as the component qualified life. Documentation shall be provided to demonstrate that the installed service conditions meet or exceed the specified service conditions.
5.2.2 Accelerated aging
Accelerated aging is the process of subjecting a component or equipment to stress conditions at a rate greater than natural aging. in accordance with known measurable physical or chemical laws of degradation. This action renders its physical and electrical properties similar to those it would have at an advanced age operating under expected service conditions. The methodology may include radiation, thermal, andlor wear aging as required. The following methods are recommended for accelerated aging of components where the component has not been exempted (see 5.1.2.3.1 and 5.1.2.3.2).
5.2.2.1 Circuit breakers and electromechanical switches
The predominant age-related failure mode of circuit breakers and switches in typical Class 1E battery charger and static inverter applications is of a mechanical fatigue nature, as induced by switching cycles (Annex D). However, an analysis of the materials employed in this device. in accordance with 5. 1 .2.3, is also required. Due to the continuous operating mode of this equipment, circuit breakers and control and power switches (and their associated annunciating relays) are cycled only during testing, preventive and corrective maintenance, and plant shutdown periods. A determination of anticipated maximum number of cycles [see item b) of 4.4] during the qualified life shall be made based on the sum of the following:
— Number of cycles required for all necessary testing prior to plant operation
— Estimated number of equipment maintenance cycles
— Number of customer-planned cycles for any purpose (equipment or plant maintenance, etc.)
The breakers and switches shall then be cycled, at their maximum load, for the number of cycles determined above. Coil-insulation systems associated with the breakers and switches shall be aged as described in 5.2.2.3. Lubricants shall also be evaluated to determine whether aging will inhibit operation of the device.
5.2.2.2 Electromechanical relays
The predominant age-related failure modes of electromechanical relays in typical Class 1 E battery charger and static inverter applications are as a result of fatigue due to operating cycles and failure of the coil insulation system. The operating mode of each relay shall be identified as follows:
— Normally energized—low-duty cycle (relay used during maintenance and testing, etc.)
— Normally de-energized-—high-duty cycle
— Normally dc-cncrgizcd—-low-duty cycle
The maximum expected number of operating cycles of each relay shall be determined for the equipment qualified life based on the relay’s use in the equipment and the same criteria in 5.2.2.1. All relays shall be cycled under simulated service conditions for the number of cycles determined above. The coil-insulation system shall be aged as described in 5.2.2.3. An analysis of the materials employed in these devices, as described in 5. 1.2.3, is also required.
5.2.2.3 Magnetic components
The life of magnetic components, as used in chargers and iiwerters, is determined by the insulation system (see IEEE Std 259). An insulation system, on which thermal evaluation has been performed and correlated temperature versus age data has been established, shall be employed. Magnetic components shall be subjected to accelerated aging to the desired qualified life in accordance with 3.2 of IEEE Std 259.
5.2.2.4 Wire, cable, terminal blocks, and connections
Insulated wire and cable shall be qualified for temperature, humidity, and time required for normal service of this equipment by the methods described in IEEE Std 383. Connectors shall he qualified for temperature, humidity, and time required for normal service of this equipment by the methods described in IEEE Std 572TM [BlO]. The basis for qualification shall include pre-aging data to simulate qualified life (such as Arrhcnius plots with 95% confidence limits). Wire and cable insulation used in equipment units to be qualified by type testing shall be thermally aged in accordance with this data. Where practical, wire shall be aged in harnesses with connectors and terminal blocks attached, in order to test the integrity of the connection methods employed in the aged condition.
