Ampcontrol ECD, Руководство пользователя, Страница: 15 / 29

Ampcontrol CSM Pty Ltd - ABN 35 000 770 141
ECD User Manual
Rev 3 – March 2020
ECDB005R0 13/03/2020 13:12
Page 15 of 21
6 AS/NZS 2081 PROTECTION FUNCTION: EARTH CONTINUITY
The primary function of the ECD relay is to provide Earth Continuity protection in accordance with AS/NZS 2081: 2011 . This
protection ensures the integrity of the earth connection between an outlet and a load via the pilot conductor in the cable.
In a typical installation the ECD’s pilot terminal will be connected to the pilot conductor of a trailing or reeling cable. The load
end of the pilot conductor will then be terminated with a diode to earth, creating a return path through the earth conductors of
the cable to the main earth point of the outlet and then to the ECD’s IS earth terminals. The ECD measures the resistance of
this pilot-earth loop (series resistance) and the pilot resistance to earth (shunt resistance). If the pilot-earth loop is not healthy
(series resistance greater than the selected trip value or shunt resistance lower than 1.25kΩ ), a trip occurs which de-energises
the output relay within the selected trip time.
The trip can be configured as latching or non-latching. This allows the user to choose if the trip is manually or automatically
reset once the pilot - earth loop is healthy.
CAUTION!
Cable parameters are important to the correct operation of the Pilot E/C function.
Resistance & capacitance values limit the length of cable that the relay can drive.
6.1 Series Resistance
The ECD relay measure the series resistance of the pilot-earth loop by applying a positive voltage to the pilot conductor and
measuring the pilot current. If the series resistance is detected to be above the user selected level, the ECD de-energises its
output relay and the LEDs on the front panel will indicate an open circuit fault. The pilot-earth loop resistance will still
continuously be monitored even in the event of a trip.
The ECD cannot be re-started until the fault has been cleared.
A power cycle will not reset the trip.
In non-latching mode, the ECD will automatically reset after the fault has been cleared.
In latching mode, a manual reset is needed after the fault has been cleared.
The trip level and time can be selected using the rotary switch on the front panel.
6.2 Shunt Resistance
The ECD measures the shunt resistance (pilot to earth) by applying a negative voltage to the pilot conductor and measuring the
pilot current. If the shunt resistance is detected to be below 1.2 5kΩ, the ECD’s output relay will be de-energised and the LEDs
on the front panel will indicate a short circuit fault. The shunt resistance will still continuously be monitored even in the event of
a trip.
The ECD cannot be re-started until the fault has been cleared.
A power cycle will not reset the relay.
In non-latching mode, the ECD will automatically reset after the fault has been cleared.
In latching mode, a manual reset is needed after the fault has been cleared.
The trip time can be selected using the rotary switch on the front panel.