IEEE 650:2017 pdf free download – IEEE Standard for Qualification ofClass 1E Static Battery Chargers,lnverters, and Uninterruptible Power Supply Systems for Nuclear Power Generating Stations
5.1 Analytical requirements
An analysis shall be performed on all components within the charger or inverter to determine whichcomponents are required for the performance of its safety function and which components are not.
5.1.1 Non-safety component analysis
A failure modes and effects analysis (FMEA) shall be performed, in accordance with 4.2 of IEEE Std 577,on all components presumed to be non-safety components.”The FMEA shall demonstrate that the failure ofthese components, as used in the circuit throughout the qualified life of the equipment, does not affect theability of the charger，inverter, or UPS systems to perform its safety function (see 4.2.2) or, by way ofinterfaces，does not affect the safety functions) of other equipment.The non-safety components shall beassembled into the sample equipment without additional analysis or testing.Any component whose failureis determined to affect the ability of the charger or inverter to perform its safety function by the FMEAshall be considered a safety component and is addressed in 5.1.2.
5.1.2 Safety component analysis
Components designated as safety components are those whose failure affects the ability of the charger,inverter, or UPS systems to perform its safety function or, by way of interfaces, affects the safety functionof other equipment. They shall be analyzed in accordance with the requirements of this subclause.
5.1.2.1 Software analysis
lf a programmable digital device is contained within the Class 1E static battery charger,inverter, or UPSsystem then it needs to be developed or commercially dedicated in accordance with the standard criteria inIEEE Std 7-4.3.2.
5.1.2.2 Operational stress analysis
An essential part of the qualification of this equipment is to verify the integrity of its design.Thus, as partof the qualification process，a stress analysis of the equipment shall be performed to assure that noelectrical component is stressed to a point where its aging is accelerated beyond that expected in operation.Should any components be overstressed, a redesign shall be performed to correct this condition. Typicalstress levels for voltage and power of 0.5 or less are not considered a contributor to aging. Annex Aprovides background information on this topic, as well as an example of a stress analysis.
5.1.2.3 Component classification
All safety components within the charger, inverter, or UPS systems shall be classified as either componentsfor which aging is not a significant failure mechanism or components for which aging is a significantfailure mechanism.An aging mechanism is significant if, in the normal and abnormal service environment,it causes degradation during the installed life of the equipment that progressively and appreciably rendersthe equipment vulnerable to failure to perform its safety function(s) under DBE conditions (see 7.3.2 ofIEC/IEEE 60780-323). Operating experience，testing, and analysis may be used in this classificationprocess.
5.1.2.3.1 Components without significant aging mechanisms
lf the components are designed and manufactured with the same techniques used to manufacture thecommercial grade equivalent of Mil-Spec components, and they are applied within their design rating (asdetermined by the stress analysis in 5.i1.2.2) and a radiation environment less than 1.0E +03 rads, then theaging effect on the components will not be significant during the qualified life of the equipment in whichthey are installed.
Aging may not be a significant failure mechanism for the components identified with a Phi symbol.These components must be designed and manufactured with the same techniques and materials ascomponents that exhibited no difference in performance due to age-related degradation.Component dataused to make such a determination must be technically justifiable.Any differences between the specificcomponents used in a charger or inverter and those identified in the publication must be justified.