Section 13 Checking the directionality
13.1 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.
13.2 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 IMinOpPG and IMinOpPP for ZDRDIR or
ZDMRDIR are available under the HMI menu: Main menu/
Settings/IED Settings/Impedance protection/
DirectionalImpedance
1MRK 504 165-UUS - Section 13
Checking the directionality
Transformer protection RET670 2.2 ANSI 293
Commissioning manual
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