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We have facility of Gas Turbine 25MVA (Brush Generator) at our power plant, form last few month an alarm appears on system with description of Diode Failure Rotor Interval Fault. Alarm frequency is high and shortly it become normal automatically.
Event history shows alarm in every second or several alarms in one second with different time intervals and it happens continue for few hours.
Installed relay on Rotor Protection is MRR1-D (SEG), during alarm relay didn't shows any indication on display but appears relay latching and de-latching sound continuously.
*No any tripping on this relay only alarm will raise on system.
We take the values from relay installed and default values of spare one which we are going to plan for replace in shortly incoming shutdown of turbine.
Measuring Values (for description see manual 3.2 > http://www.dsfweb.com/upload/proddo...df?PHPSESSID=1824d4532820e35d1511985ccd550cc1)
Ir was 11%
Unfortunately we didn't measure the values during alarm (of like Ir: ripple component of exciter current see manual 5.1) To ensure the typical values of Ir (see manual 4.2)
So please put your opinion and suggestion.
Replacement of relay will kill the cause of alarm or some test of diodes should be taken or which causes can exist behind the alarm.
Event history shows alarm in every second or several alarms in one second with different time intervals and it happens continue for few hours.
Installed relay on Rotor Protection is MRR1-D (SEG), during alarm relay didn't shows any indication on display but appears relay latching and de-latching sound continuously.
*No any tripping on this relay only alarm will raise on system.
We take the values from relay installed and default values of spare one which we are going to plan for replace in shortly incoming shutdown of turbine.
Measuring Values (for description see manual 3.2 > http://www.dsfweb.com/upload/proddo...df?PHPSESSID=1824d4532820e35d1511985ccd550cc1)
Ir was 11%
Unfortunately we didn't measure the values during alarm (of like Ir: ripple component of exciter current see manual 5.1) To ensure the typical values of Ir (see manual 4.2)
So please put your opinion and suggestion.
Replacement of relay will kill the cause of alarm or some test of diodes should be taken or which causes can exist behind the alarm.
