The digitally controlled KCM165K monitors insulation level between a non-live non-grounded (IT) AC system and its protective earth. This unit is used for marine, offshore, seabed and down hole installations for megging in standby position.
An AC or DC auxiliary voltage is required for the unit. Only ONE KCM16K can be connected to each IT-system. The ohmmeter and the triple-zone status LEDs give at a glance the clear safety message:
IDV MEASURING PRINCIPLE
Insulation is measured between the complete galvanically interconnected AC network and its protective earth. The unit injects a DC measuring signal into the monitored system. The signal flows to ground via the path of the insulation fault, the level of flow indicates the insulation resistance. The measuring accuracy is not influenced by any normal kind of load attached to the AC network. The KPM165K measures all phases just by connection to either line or neutral point.
Start of monitoring function is delayed when auxiliary power is switched on (default 30 secs delay) to avoid false reading caused by initial charging of network spread capacitance. If powered from separate source there can be a stabilizing time if there is network spread capacitance.
When auxiliary power is OFF the unit input is automatically protected against "megger" test voltages up to 1.4kVDC, and incorrect measurements caused by the unit’s input impedance are avoided.
The unit has C/O relay outputs for Warning and Alarm. The Alarm 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. Trip levels and delays are settable on unit front.
The unit is supplied with an isolated analogue output proportional to insulation level. If output is used for remote meter reading, we recommend 0-1mA for the slave indicator.
To protect the KCM165K and personnel against high voltage exposure a voltage adapter is needed for line-voltage above 750V.
Reset / Parallelling Disable Function
KCM165K has a built-in disable function. When connecting two or more
IT-networks together only one unit can be active, the other(s) must be
disabled. When unit is disabled the power led will flash every 2 seconds
to indicate that unit is inactive.