Utilities Middle East – August 2019

(Kiana) #1


30 Utilities Middle East / August 2019 http://www.utilities-me.com


very protection system must work
safely, quickly and in a targeted
manner. The aim of this requirement
is to deliver a supply of energy that is
as stable as possible and, most importantly,
to ensure the safety of electrical energy facil-
In the fi eld of relay testing, various suppli-
ers off ering well-proven devices together
with a generally accepted set of methods
regarding how testing is to be carried out
have been around for many years. However,
even the most thoroughly tested protection
relay will not be doing its job if it is unable to
detect an event caused by a one-off wiring
Wiring testing is, therefore, vital - especially
when commissioning a new or modifi ed
installation - and should be a process carried

but not all of them are examined in detail.
If we look at the confi guration that crops
up most frequently in the fi eld, that is, a
three-phase system with three current and
three voltage transformers, the following
errors might occur. They should, therefore,
be looked for every time a test is carried out;
incorrect polarity in the current transformer,
current transformer installed in wrong
direction, current transformer circuit not
grounded, additional unintentional ground
connections and malfunction of a relay test
plug or relay test connector.
Other elements to be looked for include
break in the secondary wiring of current or
voltage transformers, polarity error in the
secondary wiring, phase reversal in the sec-
ondary wiring and installation direction of
current transformer incorrectly set in relay.

out according to a standard that is likewise
broadly accepted.
Operators of electrical energy facilities
have shown there does not appear to be an
established standard for wiring testing. Most
companies rely on an in-house process for
wiring testing that has been developed over
the years from their respective experiences.
The basic idea behind this approach
addresses the question of what errors should
be found (or, ideally, not found) when test-
ing wiring. In this article, the authors propose
a reliable method for wiring testing that has
been developed on the basis of this question
and the fi ndings from the interviews.
It can be carried out with minimal outlay
while providing as high a level of safety as
possible. To keep the length of this article
within bounds, the various steps are listed,

With the COMPANO 100, OMICRON has developed a test set that is optimised to test the wiring
from the transformers to the relays, meters or control room



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