Abstract—Testing is the last line of defense for relay system
performance before the switch is thrown. The power supplier
must be assured the system will protect for all possible faults,
over- and undervoltage, and other actionable conditions under
continuingly varying system status. The power supplier must also
be assured the protective system will not generate false trips or
overtrip, causing undue outages or other adverse power quality
conditions for its customers. Installing a relaying system,
performing basic tests, and then hoping for the best is no longer
an acceptable way to do business in light of problems that have
occurred in the last few years. The relaying system must be
“dialed in” before the line is energized.
Throughout the power industry, there are a variety of
philosophies on testing relays that vary from basic go/no-go tests,
to power system simulation, to installed system end-to-end tests.
We will explore these various methods by compiling field testing
experience and comparing the results achieved. We will analyze
how many potential problems were found with equipment, relay
settings, relay logic, or other things.
Modern relays provide sophisticated logic to provide
traditional functionality but can be used to provide more
complex custom control. The typical engineer does not have the
means to reliably test programming from behind the desk. These
tests are normally performed in the field. Training and guidance
are needed for engineers and technicians so they can develop
comprehensive and fool-proof tests to ferret out any potential
problems.