REJ603BB401NN3XE ABB Numerical Feeder Protection Relay

ABB REJ603BB401NN3XE Protection Relay

The ABB REJ603BB401NN3XE, also cataloged as the REJ603 Protection Relay, operates as a dedicated hardware component for numerical overcurrent and earth-fault protection within secondary distribution switchgear platforms.

Hardware Specifications

Industrial Control and Firmware Compatibility

The REJ603BB401NN3XE utilizes a self-powered architecture, deriving operating energy directly from phase current and earth-fault measurement transformers. This eliminates the dependency on external auxiliary power, providing protection capabilities in remote switchgear environments. Firmware flash compatibility is managed via ABB Relion software, ensuring that protection stages—including low-set, high-set, and instantaneous overcurrent functions—are synchronized with the distribution feeder parameters. The module architecture supports I/O density scaling through binary inputs and remote trip interfaces, allowing for seamless integration into existing Ring Main Unit (RMU) protection schemes.

Frequently Asked Questions

Q: Does the relay maintain protection settings during a complete loss of primary current?

A: Without primary current, the self-powered circuitry will eventually de-energize. When an optional auxiliary or USB power source is utilized, the relay maintains its operational state and HMI display functionality independently of the CT input levels.

Q: Is the impulse output capable of driving conventional magnetic trip coils?

A: The impulse output is specifically engineered for low-energy trip coils. It does not provide the sustained high current required for conventional magnetic trip coils and requires an interposing interface if used in high-load applications.

Field Installation Guidelines

1. Mounting: Secure the relay into the panel cutout of the RMU or switchgear cubicle. Verify the chassis gasket is compressed evenly to maintain the designated IP rating of the front face.
2. Wiring: Terminate CT secondary leads at the rear interface, ensuring correct phase polarity to avoid biased earth-fault readings. Use appropriate wire ferrules to maintain low-contact-resistance at the terminals.
3. Grounding: Connect the protective earth terminal of the relay directly to the switchgear common grounding bus with a low-impedance conductor to divert high-frequency transients.
4. Configuration: Utilize the Relion software interface to load configuration parameters. Validate the pickup and trip time settings using secondary current injection to confirm the logic operates within the desired protection curves.