A protocol to synchronize independent clocks running on separate nodes of a distributed measurement and control system to a high degree of accuracy and precision is specified. The protocol is independent of the networking technology, and the system topology is self-configuring.

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The scope of this standard encompasses those products of system and software development that capture architectural information, referred to as "e;architectural descriptions"e;. This includes architectural descriptions that are used for the following: a) Expression of the system or software and its evolution b) Communication among the stakeholders c) Evaluation and comparison of architectures in a consistent manner d) Planning, managing, and executing the activities of development e) Expression of the persistent characteristics and supporting principles of a system or software to guide acceptable change f) Verification of an implementation's compliance with an architectural description g) Recording contributions to the body of knowledge of systems and software architecture

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This standard sets terms, test methods and measurement procedures for series connected, self-restoring current limiter components used in low-voltage telecommunication circuit surge protectors. It is only applicable for components in telecommunications circuits with voltages equal to or less than 1000 V rms or 1200 V dc. The self-restoring current limiters covered by this standard have the following properties: · Excessive current causes a transition from a low-resistance state to a high-resistance state · Reverts to a low-resistance state when the excessive current ends · Directly operated by the current flow through the component · Solid-state (no moving parts) · Withstands specified levels of impulse · Withstands specified AC voltage levels when in the high-resistance state Examples of this type of current limiter technology are positive temperature coefficient step-function thermistors of ceramic or polymeric material and silicon semiconductor based electronic circuits. This standard does not cover self-restoring current limiter components used in other applications, such as heaters, inrush-current limiters or sensing devices. Current interrupting type components, which reduce the current to zero by a mechanical circuit break, are not covered by this standard. In this standard, a telecommunications circuit is a circuit that uses metallic conductors to handle the remote transmission of information, such as data, communications and signalling.

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Metal-oxide surge arresters designed to repeatedly limit the voltage surges on 48 Hz to 62 Hz power circuits (>1000 V) by passing surge discharge current and automatically limiting the flow of system power current applies to this amendment. This amendment covers devices for separate mounting and to those supplied integrally with other equipment. The tests demonstrate that an arrester can survive the rigors of reasonable environmental conditions and system phenomena, while, at the same time, protect equipment and/or the system from damaging overvoltages caused by lightning, switching, or other undesirable surges.

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This standard applies to metal-oxide surge arresters (MOSAs) designed to repeatedly limit the voltage surges on 48 Hz to 62 Hz power circuits (>1000 V) by passing surge discharge current and automatically limiting the flow of system power current. This standard applies to devices for separate mounting and to devices supplied integrally with other equipment. The tests demonstrate that an arrester can survive the rigors of reasonable environmental conditions and system phenomena while protecting equipment and/or the system from damaging overvoltages caused by lightning, switching, and other undesirable surges.

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Information and general recommendations of instrumentation, circuitry, calibration, and measurement techniques of no-load losses (excluding auxiliary losses), excitation current, and load losses of power and distribution transformers are provided. The guide is intended as a complement to the test code procedures given in Clause 8 and Clause 9 of IEEE Std C57.12.90-1999.

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In this standard a method for establishing the dollar value of the electric power needed to supply the losses of a transformer or reactor is provided. Users can use this loss evaluation to determine the relative economic benefit of a high-first-cost, low-loss unit versus one with a lower first cost and higher losses, and to compare the offerings of two or more manufacturers to aid in making the best purchase choice. Manufacturers can use the evaluation to optimize the design and provide the most economical unit to bid and manufacture. The various types of losses are reviewed.

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This guide describes performance, functional and communication needs of Phasor Data Concentrators (PDC) for power system protection, control and monitoring applications. The guide covers synchrophasor system needs and testing procedures for PDC. It includes functional requirements for associated interfaces with Phasor Measurement Units (PMU) to PDC and PDC systems. In particular, it includes requirements for synchronization, synchrophasor data processing, real-time access and historical data access.

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This guide presents practical line current differential schemes using digital communication. Operating principles, synchronization methods, channel requirements, current transformer requirements, external time reference requirements, backup considerations, testing considerations and troubleshooting are included. It also provides specific guidelines for various application aspects including multi-terminal lines, series compensated lines, mutual coupled lines, line charging current, in-zone transformers and reactors, single-pole tripping and reclosing as well as channel and external time sources requirements.

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The document provides guidance for Synchronization, Calibration, Testing, and Installation of Phasor Measurement Units (PMU) applied in Power System Protection and Control. The following are addressed in this Guide: * Considerations for the installation of PMU devices based on application requirements and typical bus configurations. * Techniques focusing on the overall accuracy and availability of the time synchronization system. * Test and calibration procedures for phasor measurement units (PMUs) for laboratory and field applications. * Communication testing for connecting PMUs to other devices including Phasor Data Concentrators (PDC).

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