The Holistic Neutral Earth Protection system (HNER) has been designed to ensure safety and compliance. This relay system continuously monitors the resistive value of the earth fault limiting Resistor (NER), and the neutral current value. As the relay is fully programmable via the door mounted HMI each relay can monitor a Neutral resistor value of up to 650 ohms making this single relay usable at all system voltages up to 4000V AC Phase to Phase. Higher voltages are possible using an alternate barrier.

The system continuous monitors the Neutral resistor value and the Earth leakage current to ensure maximum reliability of equipment and safety of your personnel.

Each relay has dual power supply functionality allowing them to be supplied from either 110-240V AC/DC or 24-48V AC/DC at 50/60Hz. Thus, reducing site spares.

The NER integrity is confirmed via two (2) independent trip contacts (9-14) these change over contacts will activate if there is a change in the resistive value of the NER or an increase in the Neutral voltage. The earth leakage current in the neutral is continuously monitored via an independent toroid, in the event excessive leakage current is detected 2 additional change over relays (41-46) will operate.

Remote diagnostics and monitoring are provided via the Modbus and analog connections. The Modbus offers real time protection settings, measured values and relay status while the 4-20mA or 2-10V analog allows measured earth leakage levels. The serial communications has two selectable protocols available – Modbus ASCII and Modbus RTU.

The NER barrier provides isolation from potentially high Neutral voltages that are experienced during an Earth Fault. The Barrier should be mounted adjacent to the NER being monitored, leaving the HNER relay with a maximum of control voltage.

The system can be configured to be either failsafe/non-failsafe as well as either latching/non-latching depending on the application. (Changes may affect compliance with AS2081)