Section 13 Checking The Directionality; Overview; Testing The Directionality Of The Distance Protection - ABB RET670 Commissioning Manual

1MRK 504 165-UEN A
Section 13
13.1
13.2
Transformer protection RET670 2.2 IEC
Commissioning manual
Checking the directionality

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 the following.

Testing the directionality of the distance protection

The test is performed by looking at the information given by the High speed
distance protection ZMFPDIS, ZMFCPDIS or the directional function ZDRDIR or
ZDMRDIR whichever is used.
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:
• load current > 5% of base current
• Otherwise the settings IMinOpPE and IMinOpPP for ZDRDIR or
ZDMRDIR are available under the HMI menu: Main menu/
Settings/IED Settings/Impedance protection/
DirectionalImpedance
The primary load impedance must have an angle (PHI) between the setting
angles for the directional lines. In case of default settings this means:
Section 13
Checking the directionality
GUID-7E504488-F341-477A-953A-EB0B262911EB v2
GUID-EB5380B2-6086-4814-8890-102E55A79C82 v4
283