REM620 offers a variety of functionalities which can be utilized in different asynchronous or synchronous motor applications.
The protection and control relay's basic configuration offers all the functionality needed to manage motor starts and normal operation, also including protection and fault clearance in abnormal situations. The main features of the relay include motor short-circuit and overload protection, thermal overload protection, motor start-up supervision, locked rotor protection and protection against too frequent motor starts. The relay also incorporates non-directional earth-fault protection, negative phase-sequence current unbalance protection and backup overcurrent protection. Furthermore, the relay offers motor running stall protection, loss of load supervision and phase reversal protection.
Additionally, the basic configuration offers directional earth-fault protection, three-phase undervoltage protection, negative-sequence overvoltage and positive-sequence undervoltage protection. The configuration also includes frequency protection consisting of overfrequency, underfrequency and rate-of-change frequency protection modes.
In the CT & VT variant, the basic configuration contains differential protection functionality. A stabilized and instantaneous differential protection function utilizing three-phase current measurements from the terminal side of the motor and three-phase current measurements from the neutral side of the motor is available in the basic configuration. The basic configuration also includes differential protection function based on high-impedance or flux-balance, also known as core balance, protection method. A restricted earth-fault function is also available.
REM620 offers an optional protection function package for synchronous motors including functions for protecting synchronous motors with directional overpower and underpower and underexitation protection. A rotor earth-fault protection function is already available in the basic configuration. The synchronous motors package also includes some functions usable in distributed power generation when the utility grid codes require functionality such as low-voltage ride-through or directional reactive power and undervoltage protection.
RTD/mA measurements can be used for supervising motor conditions and alarming when the set limits are exceeded.
In certain motor drives of special importance, there must be a possibility to override the motor thermal overload protection to perform an emergency start of a hot motor. To enable an emergency hot start, REM620 offers a forced start execution feature.
Enhanced with optional hardware and software, the relay also features three light detection channels for arc fault protection of the circuit breaker, busbar and cable compartment of metal-enclosed indoor switchgear.
The arc-fault protection sensor interface is available on the optional communication module. Fast tripping increases staff safety and security and limits material damage in an arc fault situation. A binary input and output module can be selected as an option - having three high speed binary outputs (HSO) it further decreases the total operate time with typically 4...6 ms compared to the normal power outputs.