REM620 has been designed to be the main protection in the manufacturing and process industry for medium-sized and large asynchronous and synchronous motors that require also differential protection. Typically, the motor protection relay is used with circuit breaker- or contactor-controlled MV motors and with contactor-controlled, medium-sized and large LV motors, in a variety of drives. These include both continuously and intermittently operated asynchronous and synchronous motor drives with varying load.
REM620 can be used with either single- or double-busbar configurations with one or two breakers and with numerous switching device configurations. The relay supports a substantial number of both manually and motor-operated disconnectors and earthing switches, and it is capable of running large configurations. The number of controllable devices depends on the number of inputs and outputs left free from other application needs. The number of available I/Os can be increased with the RIO600 Remote I/O device.
The relay offers extensive possibilities for tailoring the configurations to end application requirements. The tool suite for all Relion relays is Protection and Control IED Manager PCM600, which contains all the necessary tools for configuring the device, including functionality, parameterization, the HMI and communication.
REM620 is thoroughly adapted for earth-fault protection. By using cable current transformers, a sensitive and reliable earthfault protection can be achieved. Phase-current transformers in Holmgreen (summation) connection can also be used for earthfault protection. To further improve the arc protection and minimize the effects of an arc fault, the 620 series relays ordered with the arc protection option can be equipped with an I/O card featuring high-speed outputs operating in one millisecond.
Figure 1. A dedicated motor substation with the different motor starting methods combined in one switchgearFigure 2. Direct-on-load starting method, with the motor directly connected to the medium-voltage switchgearFigure 3. Motor started over reactor choke, which decreases motor starting current over the reactor and helps handle the load flow in the medium-voltage networkFigure 4. Motor starting method with variable-frequency drives VFD that make the control easier and optimize energy consumptionFigure 5. Motor protection with flux-balance-based differential protectionFigure 6. Larger MV synchronous motor with differential protection, started with autotransformerFigure 7. REM620 for larger MV synchronous motor with brushes with differential protection and rotor EF protectionFigure 8. Overload and shortcircuit protection for motors with sensor variant