Ground fault indicator G-Finder™

HOME > English_TOP > NiGK Product lineup > Flashover indicators > Ground fault indicator G-Finder™

A clear indicator of the ground fault tower

The G-Finder™ detects ground faults caused not only by lightning but also by animals, etc. and then indicates the fault tower. It utilizes the fault current as a power source, therefore no battery is necessary. G-Finder™ is highly effective in early detection of the ground fault tower.


  1. Available for powerline below 500kV (also for Multilinear)
  2. Detect faults by the fault current phase
  3. No power sources
  4. Can be attached to a hot line
  5. Can be detected from the ground
  6. Replace indicators only after operation
  7. No maintenance necessary

Operation principles (G15H)

The ground fault current is detected by the detection coil fitted to the overhead ground wires on either side of the tower. If a ground fault occurs, the fault current branches to the overhead ground wires as well as to the ground. Additionally the fault current branches to the towers adjacent to the fault tower where the G-Finder™ detects the phase difference of these currents and indicates only the fault tower. Generally, phase detection needs IC circuits and power, but Gfinder needs no battery thus no maintenance is necessary. For the towers without ground wires, G3HC, G3HS or G0 are applicable.



G15TH is for three-way branch and G15X is four-way branch

Specification by type


Type System Number of overhead
ground wires
Max ground
fault current
Conditions for
G15H Resistance
grounded system
1 100A or over 30A or over 3 cycles or over 
2 200A or over
G15TH Resistance
grounded system
1 100A or over 40A or over 3 cycles or over
2 200A or over
G15X Resistance
grounded system
1 200A or over 85A or over 3 cycles or over
2 400A or over
G50 Direct
grounded system
1 to 3 1kA or over 2 cycles or over
G3HC Resistance
grounded system
None 100A or over 5A or over 15 cycles or over
G3HS Resistance
grounded system
None 100A or over 10A(5A+5A) or over  12 cycles or over
G0 No
grounded system
None Line distance 4km or over 0.5A 36 cycles or over

How to install


G-Finder How to install

*Examples for G50 and G15H on the top of a transmission tower

Accessories included


G-Finder accessories

Compatible indicators 

Validity period

G-Finder™ : 10 years
FR-type indocator : 10 years
F-type indicator (Japan only) : 5 years

Download catalogs and documents


For questions about the products,
please click the banner.

Send Inquiry

CONTACT US Please contact us anytime if you have questions.
Copyright (C)2017 NiGK Corporation All Rights Reserved.