Locator of ground fault on ungrounded
Locator of ground fault on ungrounded
(OP)
this is a 13.8kV closed ring auxiliary system of about 1.3km , to supply a hydropower plant of 25 generator(25x80MVA). See thread238-315981: synchronization with one generation.
This system is grounding with high resistance , with phase-to-earth current no more the 10A.
All fault to ground will alarm. There are 1 hour to look for the fault and recomposition of system.
Do you know any electronic device that can be installed during assembly, installation or maintenance of the system of 13.8 kV, which allows to locate ground fault in the system without having to open the ring of 13.8 kV?
This system is grounding with high resistance , with phase-to-earth current no more the 10A.
All fault to ground will alarm. There are 1 hour to look for the fault and recomposition of system.
Do you know any electronic device that can be installed during assembly, installation or maintenance of the system of 13.8 kV, which allows to locate ground fault in the system without having to open the ring of 13.8 kV?






RE: Locator of ground fault on ungrounded
Regards
Marmite
RE: Locator of ground fault on ungrounded
with core balance CT of course and with broken delta PT connection.
Possible use RMU with special indicators are operated with voltage from capacitance led's
RE: Locator of ground fault on ungrounded
what is RMU?
RE: Locator of ground fault on ungrounded
secondary switchgear.
RE: Locator of ground fault on ungrounded
RE: Locator of ground fault on ungrounded
A 13.8kV auxiliary services system consists of 5 substations (SE1, SE2, SE3, SE4, SE5) interconnected in a closed loop configuration. Each substation has loads and only SE1 has generation.
Each subestation are connected by on-load disconnect switch except generation subestation SE1 where is protection and circuit breakers.
Any fault phase-phase between SEs, will operate protection and trip at SE1 circuitbreakers.
Any fault phase-to-ground between SEs, will operate protection(59N) and alarm at SE1.
My problem is to locate ground fault in the 13,8kV ring system.
RE: Locator of ground fault on ungrounded
Are you have VT, core balanced CT at the substations?
BTW, what about indication of phase to phase fault, usually it's same problem.
Try check the following devices: Hortsmann Alpha, Hortsmann Gamma,
Alpha automatic.
RE: Locator of ground fault on ungrounded
There is only 59N sensor for the detection of fault to ground generator installed in the substation SE1.
To locate a fault to earth on a stretch of line, each section should be opened and closed the line again if the alarm does not stop.
The process is repeated for each section until the alarm ceases, which indicates the stretch of line where the fault is located.
RE: Locator of ground fault on ungrounded
RE: Locator of ground fault on ungrounded
Is this an overhead system?
RE: Locator of ground fault on ungrounded
It is insulated cable Eprotenax Compact 105-8.7/15kV - 35mm2
RE: Locator of ground fault on ungrounded
How is the cable shield grounded? That can have an impact on how such CTs will work.
RE: Locator of ground fault on ungrounded
all equipment has been tested and are being installed in the field.
RE: Locator of ground fault on ungrounded
there is a problem in my description:
To locate a fault to earth on a stretch of line, each section should be opened and closed the line again if the alarm does not stop.
The process is repeated for each section until the alarm ceases, which indicates the stretch of line where the fault is located.
problem is:
in a ungrounded system with a solid phase-to-ground fault,
there is a voltage shift at the point of fault relative to normal balanced system.
This voltage shift is can be maximum voltage 13.8/V3 kV at point of fault and reducing up to normal balanced system at generation point.
In this circumstances I guess could be dangerous to close with fault.
Conclusion: I still do not know how to locate the falt.
RE: Locator of ground fault on ungrounded
there is a problem in my description:
To locate a fault to earth on a stretch of line, each section should be opened and closed the line again if the alarm does not stop.
The process is repeated for each section until the alarm ceases, which indicates the stretch of line where the fault is located.
problem is:
in a ungrounded system with a solid phase-to-ground fault,
there is a voltage shift at the point of fault relative to normal balanced system.
This voltage shift is can be maximum voltage 13.8/V3 kV at point of fault and reducing up to normal balanced system at generation point.
In this circumstances I guess could be dangerous to close with fault.
Conclusion: I still do not know how to locate the fault.
RE: Locator of ground fault on ungrounded
G.F.
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