WEG DWE-3 Motor Protection Relay with Isolated Ground Fault Module

The WEG DWE-3-S3-I-GF is the DWE-3 electronic motor protection relay fitted with the isolated ground fault module, providing sensitive earth fault detection for motors installed in IT (isolated neutral) and high-resistance earthed power systems common in Saudi offshore platforms, hospital power systems, and some SABIC petrochemical facilities where continuous supply availability is prioritised over immediate ground fault isolation.

IT System Ground Fault Detection

In IT (Isolated Terra, or floating neutral) power systems, the first earth fault does not cause an automatic trip — instead, an earth fault monitor detects and alarms. The DWE-3-S3-I-GF's isolated earth fault module measures the fault current using a core-balance CT with high-sensitivity input, triggering an alarm output at a low threshold (configurable from 30 mA to 1 A) to alert operators of the incipient fault while the motor continues to run. A second independently set threshold provides an emergency trip if the fault current rises to dangerous levels. This two-stage alarm + trip approach is ideal for Saudi offshore platform power systems (TN-C-S and IT configurations) and hospital essential power systems.

Sensitivity and Selectivity

The isolated ground fault module achieves detection sensitivity of 30 mA, enabling detection of early-stage insulation degradation before it progresses to a full ground fault. The adjustable time delay (0–10 s) enables selectivity with downstream residual current devices in TT-earthed systems, preventing nuisance tripping while ensuring protection coordination. In Saudi petrochemical applications with long cable runs (500–2000 m from MCC to motor), the capacitive leakage current can reach several hundred mA; the DWE-3-S3-I-GF's capacitive leakage compensation function prevents false trips on these long cable installations.

Razz Middle East Application Support

Razz Middle East provides technical consultation for customers selecting between the standard ground fault module (DWE-3-S3-NT) and the isolated system module (DWE-3-S3-I-GF) based on their specific earthing system, cable length, and protection philosophy. Full commissioning support is provided for Saudi offshore, hospital, and IT-earthed industrial applications.