KPM363x - THREE CHANNEL AC EARTH FAULT GUARD
- For grounded or non-grounded live networks in land, marine and sub-sea installations
- True r.m.s. measurement not affected by heavily distorted waveforms
- 3 Individual channels
- Non-resitive earth current offset function
- Restricted or Unrestricted earth fault detection
- Highest up meter reading, Pathfinder function identifies channel trip
- Analogue output proportional to highest earth current level (F-version)
Application
The three channel digitally controlled KPM363x monitors up to three
earth current channels in a non-grounded (IT) or grounded TN network and
its protective earth. Unit can be used for either Restricted or
Unrestricted earth fault detection. There is individual relay for alarm
or trip of load breaker.
The unit reads the level of earth leakage directly in mA. The standard
range is 0-150mA. Larger scale values are available, typically 500mA,
1A, 2A, 5A and 10A. The 3-channel KPM363x automatically locks the meter
to read the
highest of the three channels.
An AC or DC auxiliary voltage is required for the unit. Start of
monitoring function is inhibited when auxiliary power is switched on
(default 2secs delay). In this way false tripping during power up.
The meter status LEDs give at a glance the clear safety message:
General
RCD MEASURING PRINCIPLE
Earth current is measured by a IG-transformers CBCT (Core Balance
Current Transformer). The measuring technique is based on the principle
that the sum of the phase currents in a fault free circuit is zero. If
an earth fault present, the sum of the phase currents is not zero. This
current differential produces a signal from the IG transformer, which is
proportional to the earth current. All loaded wires shall go through
the CBCT.
OUTPUTS
The unit has C/O relay outputs for Alarm/trip. All relays are fail to
safety configured. A trip LED flashes when the trip level is passed, the
relay trips when the delay has elapsed. The timer resets if the fault
is removed during countdown. Offset, trip levels and delay are settable
on unit front. The trip delay is common for all 3 channels.
All F versions have an isolated analogue output proportional to highest up channel. If output is used for remote meter reading, we recommend 0-1mA for the slave indicator.
OFFSET FUNCTION
Only the resistive (ohmic) earth leakage current is a measure for the
insulation condition between the AC supply and its protective earth. Any
reading of leakage current in a fault free network will be caused by
the networks spread capacitance. An offset potentiometer on the rear
allows normal reactive (capacitive) currents to be ignored.
