Evaluation of Precision Time synchronisation methods for substation applications

Title

Evaluation of Precision Time synchronisation methods for substation applications

Subject

Ethernet networks

IEC 61850

IEEE 1588

performance evaluation

protective relaying

Synchronization

smart grids

Substations

time measurement

Delay

power transmission

Optical pulses

Optical receivers

Optical transmitters

Power cables

Precision Time Protocol

Creator

David M. E. Ingram

Pascal Schaub

Duncan A. Campbell

Richard R. Taylor

Source

2012 IEEE International Symposium on Precision Clock Synchronization for Measurement, Control and Communication Proceedings, pp. 1-6

Publisher

IEEE

Date

2012-09-24

Relation

ISBN 1949-0313

Format

application/pdf

Language

en

Type

Peer-reviewed Article

info:eu-repo/semantics/conferencePaper

info:eu-repo/semantics/acceptedVersion

Identifier

10.1109/ISPCS.2012.6336630

Coverage

San Francisco, CA, USA

Abstract

Many substation applications require accurate time-stamping. The performance of systems such as Network Time Protocol (NTP), IRIG-B and one pulse per second (1-PPS) have been sufficient to date. However, new applications, including IEC 61850-9-2 process bus and phasor measurement, require accuracy of one microsecond or better. Furthermore, process bus applications are taking time synchronisation out into high voltage switchyards where cable lengths may have an impact on timing accuracy. IEEE Std 1588, Precision Time Protocol (PTP), is the means preferred by the smart grid standardisation roadmaps (from both the IEC and US National Institute of Standards and Technology) of achieving this higher level of performance, and integrates well into Ethernet based substation automation systems. Significant benefits of PTP include automatic path length compensation, support for redundant time sources and the cabling efficiency of a shared network. This paper benchmarks the performance of established IRIG-B and 1-PPS synchronisation methods over a range of path lengths representative of a transmission substation. The performance of PTP using the same distribution system is then evaluated and compared to the existing methods to determine if the performance justifies the additional complexity. Experimental results show that a PTP timing system maintains the synchronising performance of 1-PPS and IRIG-B timing systems, when using the same fibre optic cables, and further meets the needs of process buses in large substations.