Mikro MK201A User Manual

MK201A DT Earth Fault Relay User's
Guide

A BRIEF OVERVIEW

a

b
c

d

h

g

f

e

a - Auxiliary power supply indicator

b - High-set start/trip status indicator

c - Low-set start/trip status indicator

d - Earth-fault high-set adjustment

e - Trip reset button

f - Test button

g - Earth-fault low-set adjustment

h - Delay time adjustment

TECHNICAL DATA

1. Current and Time Adjustments

Earth-fault Low-set Current (l>) Adjustment

• This adjustment is for setting the minimum earth-fault current for tripping. If the
measured current exceeds this threshold value, tripping starts. After a prefixed
delay time determined by the DELAY adjustment, the trip contacts will be activated.

• The setting range is from 0.1A to 2A.

Earth-fault High-set Current (l>>) Adjustment

• This adjustment is for setting the instantaneous tripping current due to an earth-fault.

• The setting range is from 1x to 10x of the earth-fault low-set setting value.
l>> = a x l>, a = 1 to 10

• This high-set feature can be disabled by setting the tripping current to infinity ( ' )

Time Delay (DELAY) Adjustment

• This time delay setting is for setting the delay time from the start of the earth-fault
low-set tripping to actual tripping of the relay contact.

• The setting range is from 0.05 sec to 1.0 sec.

2. Light Indicators

The light indicators display the status of the system.

Indicator
AUX l> l>> Status
Off Off Off No auxiliary power supply.
On Off Off System normal mode. No tripping.

On On Off

Earth-fault low-set start.

On

Blink Off Earth-fault low-set tripped.

On Off On

On Off Blink Earth-fault high-set tripped.

Earth-fault high-set start.