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Chapter 1: General information
1. General information
1.1
DESCRIPTION
Thanks to the measuring of ground currents by means of current transformer (CT), IPR-D current protection relay
can perform protection functions according to ANSI, IAC or IEC standards. Thanks also to the indications at the
digital inputs the device can inform for example about the status of circuit breaker or disconnector to which it is
coupled, operate on the outputs and disable some functions.
1.2
APPLICATIONS
•
Primary or secondary protection for generation and distribution systems.
•
Protection of transformers, overhead lines, cables, motors and generators.
1.3
PROTECTION AND FUNCTIONALITY
Description
•
CT primary ratio selectable in 5 A steps (10 A ÷ 5000 A).
•
Inverse-time ground overcurrent .......................................................................................................... 51N / 51G
with curve selection according to ANSI, IAC or IEC/BS142:
-
moderately inverse
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normally inverse
-
very inverse
-
extremely inverse
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definite time
•
Instantaneous ground overcurrent........................................................................................................ 50N / 50G
•
Overload alarm level
•
Integral relay test with or without the output contacts intervention
•
1 trip relay
•
3 auxiliary relays that can be associated with the various functions (2 programmable relays and 1 relay
controlling any loss of auxiliary voltage -SERVICE-).
Information
The following information concerns the use of the Actual values and the Setpoints.
OVERCURRENT PROTECTION
IPR-D continuously checks the ground current in the line by means of its CT and activates an alarm and/or the
circuit breaker trip when a value exceeds the set level (called Pickup level):
1. possibility of separately setting of the timed and instantaneous overcurrent;
2. no intrinsic delay of the device is added to the instantaneous intervention;
3. ground overcurrent alarm and trip delay according to time-current curve set and to the entity of current.
CURRENT PROTECTION RELAY - IPR-D
1.1
ANSI
Manual P/N: IPR-D GBM 01/09/2006
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