Lightning Strike


Thread Starter


The power station experienced a lightning strike(GE 9FA). A number of alarms initiated. On the Generator Excitation DCS page (Mark VI) on the Control Selection this transferred from Master 1 to Master 2. Volts/Hz alarm initiated. Backup Exhaust Reference Temperature initiated The load increased immediately from 373MW to 402MW.

I am aware of the overfluxing alarm but could someone help me as to why the Backup Exhaust Reference Temperature alarm initiated and what is the significance of the Control selection transferring from Master 1 to Master 2? Is it safe to press a Reset Transfer?
The best way to try to determine what happened ('cause it's difficult to determine after the fact exactly how a lightning strike affected a control system--almost as difficult as trying to predict how a lightning strike will affect a control system; differing amounts of energy, different strike points, differing sensitivities of control devices/components, and on and on), is to work backward from the alarm condition.

In the case of the 'Backup Exhaust Reference Temp' alarm, use Toolbox to determine what causes the alarm (loss of CPD, etc.) at your site and what can be done to clear the alarm (Master Reset, etc.).

This author has no experience with recent exciter regulator control systems.