System-Level Tests of Transformer Differential Protection Using an IEC 61850 Process Bus

Title

System-Level Tests of Transformer Differential Protection Using an IEC 61850 Process Bus

Subject

Current measurement

Ethernet networks

IEC 61850

IEC standards

IEEE 1588

industrial networks

Merging

performance evaluation

process bus

protective relaying

Relays

smart grid

substation automation

Synchronization

Time factors

Creator

David M. E. Ingram

Pascal Schaub

Richard R. Taylor

Duncan A. Campbell

Source

IEEE Transactions on Power Delivery. Vol. 29, No. 3, pp. 1382-1389

Publisher

IEEE

Date

2014-06

Relation

ISSN 1937-4208

Format

application/pdf

Language

en

Type

Peer-reviewed Article

info:eu-repo/semantics/article

info:eu-repo/semantics/acceptedVersion

Identifier

10.1109/TPWRD.2013.2291789

Abstract

The IEC 61850 family of standards for substation communication systems was released in the early 2000s and includes IEC 61850-8-1 and IEC 61850-9-2 that enable Ethernet to be used for process-level connections between transmission substation switchyards and control rooms. This paper presents an investigation of process bus protection performance, since the inservice behavior of multifunction process buses is largely unknown. An experimental approach was adopted that used a Real Time Digital Simulator and “live” substation automation devices. The effect of sampling synchronization error and network traffic on transformer differential protection performance was assessed and compared to conventional hard-wired connections. Ethernet was used for all sampled value measurements, circuit breaker tripping, transformer tap-changer position reports, and precision time protocol synchronization of sampled value merging unit sampling. Test results showed that the protection relay under investigation operated correctly with process bus network traffic approaching 100% capacity. The protection system was not adversely affected by synchronizing errors significantly larger than the standards permit, suggesting that these requirements may be overly conservative. This “closed loop” approach, using substation automation hardware, validated the operation of protection relays under extreme conditions. Digital connections using a single shared Ethernet network outperformed conventional hard-wired solutions.