KOC105x - EARTH CURRENT GUARD FOR SYSTEMS WITH GROUNDED NEUTRAL
- Grounded neutral earth current Protection
- Definite Time Trip Delay
- Two individually setable alarm relays
- For use with 1A or 5A current transformers
- Non-resitive earth current offset function
Up to two individual very fast analogue output signals (<50mS), (optional)- DIN96 Slave Indicator with full current scale (optional)
Description
KOC105x monitors leakage current in a grounded neutral network and provides earth current protection.
True RMS measurement not affected by heavily distorted waveforms provides precision (1.0%) protection. Less than 50mS process time.
The standard models takes the auxiliary supply voltage from the monitored voltage (terminal 1 & 2).
It can also be delivered with optional separate DC auxiliary voltage (terminal 26 & 27), but that must be specified when ordering.
User settable trip levels and delays (definite time delays). Colour of LEDs indicate alarm status. Alarm LEDs flash during count-down.
Start of monitoring function is inhibited when auxiliary power is switched on (default 2secs delay). In this way false tripping during power up, caused by initial charging of network spread capacitance, is avoided.
OUTPUTS
Up to two individual very fast analogue output signals (optional) proportional to meter reading. If output is used for remote meter reading, we recommend 0-1mA for the slave indicator.
RELAY OUTPUTS
Relay operation depends on the selected model. Other combinations are available on request.
Safety
The instrument measuring input is overload protected against high
current <15xCT(/1A) or <3xCT(/5A). If unit is used for tripping
it is recommended to use manuel reset.
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.
Protective Earth (PE) Grounding
The neutral grounding point is monitored by a Current
Transformer (preferable class 0,5
or better). The ground connection can be directly or trough a neutral
earth resistor to reduce the maximum earth current in the network.
Any leakage to earth on the LOAD side will be seen as an imbalance situation, and will cause the Earth Current Guard to trip if leakage current exceeds the trip level settings.
Models
KCM105E
KCM105FA
KCM105FB
KCM105GE
KCM105GFA
KCM105GFB
