IEEE Std C37.237:2018 pdf download.IEEE Standard for Requirements for Time Tags Created by Intelligent Electronic Devices- -COMTAG.
IEEE Std C37.237 establishes common requirements for associating time tags with data items recorded or transmitted by intelligent electronic devices (IEDs). The standard specifics time tag attributes and requirements for describing time tag accuracy.
1.2 Purpose
This standard establishes consistent requirements for time tagging data items in a power system. This allows information from different sources to be more easily compared, thereby simplifying the process of event reconstruction and lED/system performance evaluation. This will lead to better power system reliability, gained through improved understanding of system operation under stressed conditions and a reduction in the cost of event analysis.
2. Definitions, acronyms, and abbreviations
2.1 Definitions
For the purposes of this document, the following terms and definitions apply. The IEEE Standards Dictionary Online should be consulted for terms not defined in this clause.
absolute time: Time referred to that international time standard comprising an ensemble of precise atomic clocks maintained by recognized national laboratories.
data item: Sampled analog or digital value, a transition of a digital value, or other designated event with a precisely defined data pattern.
data set: A collection of one or more data items to which a single time tag is associated.
daylight saving time: Time as adjusted to achieve longer evening daylight, especially in summer, by setting the clocks an hour ahead of the standard time.
digitized: Reprcsentcd in a digital form, most often by means of an analog to digital converter.
event record: A compilation of data, man or machine readable. which includes information describing one or more events and/or analog quantities. Event records include a time tag and data for a period of time. event time: That time when an event occurred or when a reported quantity was measured on the actual power system.
intelligent electronic device (IEP): Any device incorporating one or more processors with the capability to receive or send data/control from, or to, an external source (e.g., electronic multifunction meters. digital relays. controllers).
intended use: Use of a product in accordance with specifications, instructions, and information provided by the supplier.
local offset: Difference, in hours and sometimes fractions of hours, between universal coordinated time (UTC)
and a local time zone. Example: Pacific Standard Time (PST) is UTC-0XO0. Central European Time (CET) is
UTC+O 100.
local time: Time expressed in the custom of the local time zone. Local times are based on UTC and include a local offset, which may depend on the season. See also: summer time; time zone.
locked: Tracking a reference signal within acceptable limits.
on-time mark: A signal that indicates the beginning of a second, minute, hour etc. The most common on-time mark is 1 pulse per second (PPS).IEEE Std C37.237 pdf download.