APPROVED FOR EXTERNAL DISTRIBUTION
– PROPERTY OF AMPCONTROL PTY LTD
– NOT TO BE REPRODUCED IN PART
9 EARTH PROTECTION FUNCTIONS
The IPD relay provides the following earth protection functions:
Earth Leakage
Earth Fault Lockout
Earth Continuity
9.1 Earth Leakage Protection
The earth leakage protection function uses an Ampcontrol EL500 series toroid to measure the earth fault
current. This function is tested to AS/NZS 2081.3 - 2002. A definite time operating characteristic is
provided with adjustable trip sensitivity and an adjustable time delay.
Figure 9.1: Earth Leakage Protection Circuit Terminations
9.1.1 Operation
When a fault occurs that exceeds the trip threshold for an interval longer than that of the time delay, an
earth leakage trip is initiated. The trip opens the Main Contactor Relay (MCR) and is latched.
When a trip occurs, the “EL” LED on the remote display module is illuminated and the open collector
output on the relay is switched on to provide remote monitoring if required.
The leakage current (EL) is displayed on the RDM “Earth Fault Information” page as a % of the trip
level. When the leakage reaches 100% for the selected time delay a trip occurs.
9.1.2 Resetting a Trip
An earth leakage trip is treated as a special fault and requires an authorised person to perform the
reset function. This is achieved by operating and holding the lock button closed and then closing the
reset button.
9.1.3 Setting the Parameters
The trip level is adjustable in 50mA increments in the range of 100mA to 500mA.
The time delay is adjustable in the range of instantaneous (<50ms), 100ms, then 150ms to 470ms in
40ms increments.
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