Electrical Power & Protection


Earth leakage protection and grading

December 2008 Electrical Power & Protection

The door-mounted NewElec GA relay range offers earth leakage protection that makes them suitable for use with VSDs as they include harmonic filtering. The earth leakage trip thresholds are spread over a range of 30, 250, 375, 500 and 1000 mA. However, the trip curve characteristic is user-selectable as instantaneous or inverse IDMT.

The earth leakage relays have been approved by many leading mining houses
The earth leakage relays have been approved by many leading mining houses

The corresponding core balance CTs are available in diverse I.D. sizes but are designed for use with both instantaneous or IDMT selected trip curves. As such, protection grading for distribution networks may be achieved using the full range of relays.

GA relays are equipped with control panel mounted LEDs depicting the user selected trip curve, a relay ‘healthy’ LED and a relay ‘tripped’ LED.

The trip indicating LED is driven from the latching relay, which can only be reset by pressing the control panel mounted reset pushbutton. The main trip relay automatically resets once the earth leakage current is interrupted to permit the re-closing of the main MCCB when it has cleared the earth fault.

An additional start lock-out changeover contact shown across terminals 15 and 16 is latched open when the main trip contact energises to facilitate a forced reset on the control panel in order to re-close the circuit. An alternative use could be as an input to a PLC.

For more information contact Luc Dutrieux, NewElec, +27 (0)12 327 1729, [email protected], www.newelec.co.za



Credit(s)



Share this article:
Share via emailShare via LinkedInPrint this page

Further reading:

Power supply with scalability optimised
Schneider Electric South Africa Electrical Power & Protection
Schneider Electric has introduced the Easy UPS 3-Phase Modular to the South African marketplace. This robust uninterruptible power supply (UPS) is designed to protect critical loads while offering third-party verified Live Swap functionality.

Read more...
Prioritising arc flash safety
Comtest Electrical Power & Protection
Comtest has developed a range of thermal imaging and wireless testing tools from Fluke, designed to ensure safety is the top priority for engineers working in potentially dangerous arc flash zones.

Read more...
Hot Dip Galvanizers Association shines new light on renewable energy
Electrical Power & Protection
The Hot Dip Galvanizers Association of Southern Africa plays an important role in supporting the energy value chain – which spans clean, renewable and green energy – as it powers towards key sustainability targets.

Read more...
ACTOM supplies high-voltage equipment to wind farm project
ACTOM Electrical Machines Electrical Power & Protection
ACTOM High Voltage Equipment is currently in the process of manufacturing 400 kV and 132 kV high-voltage primary equipment for the Ummbila Emoyeni wind farm project in Mpumalanga.

Read more...
Energy measurement module for BL20 I/O System
Turck Banner Southern Africa Electrical Power & Protection
Turck’s BL20 energy measurement module enables precise monitoring of the energy consumption of single- or three-phase systems.

Read more...
Distributed energy resource management systems: a grid symphony
Schneider Electric South Africa Electrical Power & Protection
To listen to a symphony is one of the world’s great gifts. A conductor must ensure that instruments play beautifully as a whole and are kind to the ear and uplifting to the spirit yet shine in their individuality. The same can be said of a DERMS, which must effectively manage diverse energy sources to avoid compromising the grid’s integrity.

Read more...
Focus on energy sector infrastructure development can drive economic growth
Electrical Power & Protection
Post-election periods in South Africa often see a renewed focus on infrastructure development, with a specific emphasis on directing investments towards the energy sector. This strategic approach aims to accelerate economic growth, address energy challenges, and ultimately uplift the overall standard of living for the populace.

Read more...
Turning the continent into a global leader for green fuel
Electrical Power & Protection
Africa is at a turning point, with the potential to shift from being a supplier of raw materials to becoming a leader in advanced manufacturing, particularly in the growing green hydrogen market. For this transformation to happen, African countries must work together, combining their resources and talents to build a strong local economy.

Read more...
Epiroc showcases battery-electric drill rig at MINExpo 2024
Electrical Power & Protection
Epiroc recently showcased a demonstrator of the first ever Down-The-Hole SmartROC D65 battery-electric drill rig at the MINExpo exhibition in Las Vegas.

Read more...
Smart metering for utility management and sustainability
Electrical Power & Protection
Theodore Paraskevakos, a Greek-American inventor and businessman, developed the first smart meters in 1972 while collaborating with Boeing. Since then, smart meters have evolved significantly.

Read more...