Section 16 Checking the directionality
16.1 About this chapter
This chapter describes how to check that the directionality is correct for each
directional dependent function. The scope is also to verify that all analog values are
correct. This must be done with the protection system in operation; the protected
object must be energized and the primary load current must be higher than the
minimum operating value set in the IED.
16.2 Overview
Before starting this process, all individual devices that are involved in the fault
clearance process of the protected object must have been individually tested and
must be set in operation. The circuit breaker must be ready for an open-close-open
cycle.
The directional test is performed when the protected object is energized and a
certain amount of load current is available. It is also necessary to know the flow of
the load current (import or export, i.e. forward or reverse) by help of the indication
from an external instrument (energy-meter, or SCADA information).
The design of the test procedure depends on the type of protection function to be
tested. Some items that can be used as guidelines are following.
16.3 Testing the directionality of the distance protection
The test is performed by looking at the information given by the directional
function ZDRDIR or ZDMRDIR.
Procedure:
1. Make sure that all control and protection functions that belong to the object
that are going to be energized have been tested and are set to be in operation
2. Make sure that the primary load current fulfills the following conditions (by
using an external equipment):
• The magnitude of the primary load current must be higher than the
minimum operating current set for the directional elements in the IED. In
case of default settings this means:
1MRK 502 029-UEN A Section 16
Checking the directionality
229
Installation and commissioning manual
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