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Automated Event Retrieval Reduces
Operating Costs
Todd Rosenberger, Oncor Electric Delivery
David Prestwich, Matthew Watkins, and Mark Weber, Schweitzer Engineering Laboratories, Inc.
Abstract—In August 2007, Oncor Electric Delivery began
installing a centralized automatic relay event retrieval and
indexing system. With over 400 transmission substations and
3,600 relays capable of recording critical event data, Oncor
wanted to improve their existing process of dispatching a
technician to a substation each time a critical event occurred that
needed further review. Beyond the obvious operating cost savings
associated with retrieving critical event data, Oncor had
additional ideas for using the data.
Analyzing every event file where the relay sensed a fault
condition and the breaker cleared it is an opportunity to gauge
the health of the protection and control system. Relays that
generate power system event reports ranging from a few cycles to
a few seconds provide the opportunity to see fault inception,
relay response, and breaker operation. To analyze every event
file, Oncor developed a process to retrieve event records from
their protective relays.
It is often assumed that automatic event collection systems
require installation of new and potentially costly communications
equipment for high-speed data transfer. Additionally, proposed
North American Electric Reliability Cooperation (NERC)
Critical Infrastructure Protection (CIP) reliability standards are
often interpreted as mandates to apply potentially expensive and
complex firewalls or software security to associated communica-
tions channels. Considering the high costs of applying this
equipment or software across 400 transmission substations,
Oncor engineers immediately recognized significant cost savings
if the recommended security guidelines and event collection
requirements could be satisfied using existing installed communi-
cations equipment. Oncor met this goal with minimal hardware
installations. This paper highlights