The multifunction measuring relay simultaneously monitors up to nine quantities of a single- or three-phase network: undervoltage and overvoltage, voltage window, voltage asymmetry, undercurrent and overcurrent, power factor, active, reactive and apparent power, frequency and phase sequence. Each function is configured from a menu on the LCD, with its own hysteresis, response delay and start-up delay. One device replaces a set of single-function relays and simplifies wiring; the MH 9300 version has two independent relay outputs, so warning and trip can use separate paths.
DOLD lists the following applications in the datasheet: monitoring of single- and three-phase loads, emergency power supplies, voltage-dependent switching at undervoltage or overvoltage, voltage monitoring of portable equipment, motor protection on phase failure, transformer protection on asymmetric load and frequency monitoring on inverter outputs. Early detection of an irregular state allows maintenance to be planned before damage occurs.
For railways we propose it for monitoring the three-phase supply of trackside cabinets, substation auxiliaries and switchboards in technical rooms: phase sequence and phase failure, asymmetry, voltage drop, frequency at converter outputs. The datasheet contains test data according to the DNV class guideline.
Parameters (MK 9300N.11/022, from the datasheet):
