Digital Overcurrent & Ground Overvoltage & Selective Ground Relay (GDR-AEF01) User's Manual
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Kyongbo Electronics Co., Ltd.
3.
Protection Characteristics
3.1 Overcurrent Function
This relay contains the Instantaneous Time characteristic, Inverse Time
characteristic, and Definite Time characteristic to be used for overcurrent and short
circuit protection. GDR-AEF01 marks the instantaneous overcurrent element as
INST.OCR(IOCR), and the time overcurrent element as Time OCR(TOCR).
The instantaneous time characteristic is a function to output Trip signal immediately
when a current over the setting value is input, the Trip time is less than 40ms, and
the inverse time characteristic is a function between the current and the time, and the
operation time is shorter as the current is bigger. There are 4 international
standard(IEC) inverse time characteristics and 2 KEPCO type inverse time
characteristics equipped.
When applying the inverse time characteristics, select one from the 6 characteristics.
4 Inverse characteristics following the international standard(IEC255-4), and the time
and current relationship function of 2 KEPCO type characteristics are as follows.
×
sec
T = Operation Time, K and C = Relay characteristic value
I = Relay input current / Relay operation setting value
L = Characteristic curve index, M = Operation time ratio