# Gas Turbine Generator Neural Earth Resistor [NER] High Temperature



## Lim SS (Oct 20, 2020)

Dear All

There are four 6.6 kV GTGs [same size = 4 MW each, same brand] connected in parallel, monitored and controlled by Power Management System [PMS].
1st & 2nd generators are connected to NER A and 3rd & 4th generators are connected to NER B.
1st & 2nd are connected to Bus A & 3rd & 4th generators to Bus B. 
Bus Tie between Bus A & B are closed. 
One of the generator are put in droop and the power output is controlled at 1.8 MW.
This is due to the thrust bearing of its engine is experiencing high temperature. 
Due to this, there was humming sound from the NER and resistor temperature is abnormal [ 60 - 70 DegC]. 
All currents at the generators are in balance.
I would like to know you what cause the NER to be in abnormal condition [Humming sound & high temperature.
And how to resolve this issue.

Thanks in advance
Lim SS


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## joe-nwt (Mar 28, 2019)

What is the VAR loading of the 1.8MW unit compared to the others?


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## paulengr (Oct 8, 2017)

Maximum temp on an NGR with a typical grid resistor is around 600 C! They are made from stainless steel. 60-70 C is cool. Glowing cherry red on a grid resistor is just fine. When it “rusts” black rust that is chrome oxide which it sheds to protect itself. Do not clean it off.

Now if you have ceramic spiral wound resistors they have the same high temp ratings but can’t tolerate it continuously.

As to your issue need more info.


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