This paper outlines the implementation, testing and performance comparison of two protection
schemes used for Fault Location, Isolation, and Service Restoration (FLISR) in modern distribution
- Scheme 1: A vendor-specific communication-enhanced protection coordination scheme for
auto-reclosers (ARs) using Curve-Shifting Coordination (CSC) automation platform,
- Scheme 2: A non-proprietary and highspeed protection coordination scheme which uses
IEC61850-based communications (using GOOSE messages).
The key objectives of the tests and performance analysis were to capture the maximum time required
for fault detection and clearing using GOOSE message communications and to investigate the
expected response of inverter-based DERs during a fault on a study feeder.
A typical utility feeder was used as the study model in a lab environment for the benchmarking and
comparison analysis of the two schemes. The protection coordination tests were carried out by
applying faults at pre-defined locations in order to verify the coordination between the relays
associated with backbone ARs and to verify the ride-through capabilities of a battery energy storage
system (BESS) inverter supplying the feeder customers. Testing of scheme 1 protection coordination
was carried out in a real-time digital simulation environment implemented with the RSCAD software
tool. To test and verify scheme 2, three SEL relays (SEL-651R, SEL-751A and SEL-351A) with
GOOSE messaging functionality were interfaced with the real-time testing environment (RTDS®)
using a control hardware-in-the-loop (CHIL) testing.
The results obtained from the testing of Scheme 1 showed that the average time taken for an AR to
coordinate with an upstream AR through simulated CSC was approximately 40 ms, which comprises
of both the communication and processing time. On the other hand, upstream relay coordination with
GOOSE messaging could be achieved on average in approximately 9 ms. In addition to being able to
block the upstream relay faster, using IEC61850-based communications can also provide value in
enhancing trip time of the downstream relay, through a permissive or direct transfer trip (DTT)
scheme, instead of relying on loss of potential tripping for isolating a faulty section. Consequently, if
the upstream relay is blocked and the downstream relay has been tripped through a permissive signal,
the upstream relay closest to the fault can immediately operate, instead of relying on conventional
timed-overcurrent tripping for coordination which can be slow. Faster fault detection and clearing can
also lead to conditions where DERs can now effectively ride-through fault scenarios for any
downstream or adjacent feeder fault, to improve performance.
Therefore, even in the case where the upstream shift signal used in the vendor-specific scheme can be
made faster through enhancing communication media that have faster speeds (lower latency), using
IEC61850-based communications can offer more comprehensive and versatile protection coordination
schemes, agnostic to relay vendors, power system topologies, and outside of proprietary methods.
B. Kregel, C. Chandrabalan, A. Momeni, F. Katiraei, F. Rahmatian, 2020 CIGRE Canada Conference, Toronto, Ontario, October 19-22, 2020
KEYWORDS: Protection relay testing, IEC 61850, GOOSE, hardware-in-the-loop, communication assisted
protection scheme, real-time digital simulation.