We are in the process of installing MarkVIe to our one turbine. The Exciter control system is also being upgraded to EX2100e. We have installed the new panels and are able to run the turbine till FSNL. As soon as the synch is initiated the lockout relay actuates and turbine trips (L86TGT causes the trip). We also get the excessive volt/hertz trip alarm.
We have the trends on the HMI. The speed of turbine is not changing. Volts do increase. And MVAR value increases to 22 MVAR within 5 seconds and after that the turbine trips. There are no other process and diagnostic alarms.
As we have just commissioned the MarkVIe, the exciter engineer is insisting that the BUS PT and GEN PT connections are not correct although we have connected the signals as per drawings. We are getting two wires for Gen PT volts and two wires for BUS PT volts. When turbine is running on FSNL we get 60Vac on all of the four wires with respect to the ground.
We have turned the Synch Monitor on while on FSNL and connected the analog meter on one wire of BUS and one wire of GEN PT and the voltage goes from 120 Vac to 0. As soon as the voltages reach to 0 the 25A relay turns on for a moment. The same is happening with other two wires of GEN and BUS PT.
Exciter engineer is insisting to check the phase rotation of the BUS and GEN PT. We are getting only two phases for synchronization in MarkVIe panel. Is there any other method to check the phases of GEN PT and BUS PT coming to MarkVIe for synchronization? It would be helpful if anyone is able to explain the relation between MVAR and Generator terminal Voltages. Will Generator terminal voltage increase with increase in MVAR? What can be the possible reason for increase in MVAR and Generator terminal voltage in this situation?
We have the trends on the HMI. The speed of turbine is not changing. Volts do increase. And MVAR value increases to 22 MVAR within 5 seconds and after that the turbine trips. There are no other process and diagnostic alarms.
As we have just commissioned the MarkVIe, the exciter engineer is insisting that the BUS PT and GEN PT connections are not correct although we have connected the signals as per drawings. We are getting two wires for Gen PT volts and two wires for BUS PT volts. When turbine is running on FSNL we get 60Vac on all of the four wires with respect to the ground.
We have turned the Synch Monitor on while on FSNL and connected the analog meter on one wire of BUS and one wire of GEN PT and the voltage goes from 120 Vac to 0. As soon as the voltages reach to 0 the 25A relay turns on for a moment. The same is happening with other two wires of GEN and BUS PT.
Exciter engineer is insisting to check the phase rotation of the BUS and GEN PT. We are getting only two phases for synchronization in MarkVIe panel. Is there any other method to check the phases of GEN PT and BUS PT coming to MarkVIe for synchronization? It would be helpful if anyone is able to explain the relation between MVAR and Generator terminal Voltages. Will Generator terminal voltage increase with increase in MVAR? What can be the possible reason for increase in MVAR and Generator terminal voltage in this situation?