Series: SE-330

The SE-330 series is an advanced ground-fault and neutral-grounding-resistor monitoring relay that is compliant with Rule 10-302 of the 2018 Canadian Electrical Code Part I (CE Code). It measures neutral current, neutral-to-ground voltage, and neutral-to-ground resistance. It provides continuous monitoring of the neutral-to-ground path to verify that the neutral-grounding-resistor (NGR) is intact and that it has not been bypassed or shorted. An open NGR renders current sensing ground-fault protection inoperative and could result in a false belief that the system is functioning properly. A shorted NGR results in higher-than-expected ground-fault current. A unique LED flashing code provides external confirmation for plant safety teams and inspectors when standards-compliant protection has been configured and is active.

The SE-330 can be used with low- and medium-voltage transformers and generators with low- or high-resistance grounding used in processing, manufacturing, chemical, pulp and paper, petroleum, and water-treatment facilities. For applications above 35 kV, use the SE-330HV. For applications that require conformance to Australian/New Zealand standard AS/NZS 2081, use the SE-330AU.

Complete setup of the SE-330 requires connection to a PC running SE-MON330 software v4.10 or higher. There are three available protocol options for network communications:

• IEC 61850 - with dual RJ45, SC Fiber and RJ45, or Dual SC Fiber Interface
• Modbus TCP and Ethernet/IP - with dual RJ45, SC Fiber and RJ45, or Dual SC Fiber Interface
• DeviceNet - with CAN interface

For applications where existing switchgear is inaccessible or where a separate control panel is desirable, the SE-330 is also available within a NEMA 4X enclosure. The NGRM-ENC series is available with various options, including a surface-mounted or door-mounted SE-330 to fit specific customer applications.

Resistor Monitoring
The SE-330 combines the measured values of resistance, current, and voltage to continuously determine that an NGR is intact. It is able to detect an open or shorted resistor with or without a ground fault present. Sensing resistors are matched to the system voltage and are used to monitor NGRs on systems up to 72 kV.

Ground-Fault Monitoring
The SE-330 uses an application-appropriate current transformer to reliably detect ground-fault currents as small as 100 mA. Discrete-Fourier Transform (DFT) filtering ensures that false trips due to harmonic noise from adjustable-speed drives do not occur. Should the resistor open and a ground fault subsequently occur, the SE-330 will detect the fault through voltage measurement while other current-only sensing relays would be ineffective.

Pulsing Ground-Fault Location
The SE-330 is capable of controlling a pulsing contactor, which is used to switch the NGR resistance in a pulsing-compatible NGR package. The resulting ground-fault current is distinguishable from charging currents and noise and will only appear upstream of the ground fault, making fault location fast and easy, even without isolating feeders or interrupting loads.