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Our on-site GE gas turbine uses the GE Mark V HMI control system。There are some problems on site, hope to get support.
Two days ago, the site experienced a lightning strike, which caused the gas turbine unit to trip. Upon inspection, it was found that the R controller was in state A6. Further diagnostics revealed that the TCQA card under the R controller was not recognized. After replacing the TCQA card, the system recovered to normal operation.
Additionally, it was observed that the TBQC card in the R core was damaged, showing visible burn marks. After completing the necessary component replacements, preparations were made to restart the unit. During startup, it was noticed that all previously forced signals had been cleared from the force list. After reapplying the required forced signals, the unit started successfully.
During the synchronization process, the generator voltage displayed normally on the Mark V HMI. However, when the synchronization command was issued and the grid voltage signal was received by the Mark V system, both the generator voltage and the grid voltage readings began fluctuating simultaneously.
Voltage measurements were taken at the terminal blocks for both generator and grid voltage signal inputs. The measured voltages were approximately 100V AC on both sides and remained stable (no fluctuation observed). Interestingly, when either the generator or grid voltage signal wires were disconnected — leaving only one side connected — the remaining voltage signal became stable without fluctuation.
Based on the signal path of the generator and grid voltage measurements, several components were replaced for troubleshooting, including the PTBA and TCEB cards in the P core, and the TCCB card in the C core. The X, Y, and Z TCEA cards in the P core were also replaced, but the problem persisted.
Further tests were conducted by disconnecting the grid-side voltage signal wires and connecting the generator voltage wires to the grid-side terminals. Under this configuration, both voltage readings on the Mark V remained stable. Similarly, when the generator voltage signal was disconnected and the grid voltage signal was connected to the generator-side terminals, both voltages displayed stably without fluctuation.
Finally, both the generator and grid voltage signal wires were disconnected, and a relay protection tester was used as a signal source to inject voltage signals into the generator and grid voltage channels. Under this simulated condition, the voltages displayed in the Mark V system were stable and showed no fluctuations.
Two days ago, the site experienced a lightning strike, which caused the gas turbine unit to trip. Upon inspection, it was found that the R controller was in state A6. Further diagnostics revealed that the TCQA card under the R controller was not recognized. After replacing the TCQA card, the system recovered to normal operation.
Additionally, it was observed that the TBQC card in the R core was damaged, showing visible burn marks. After completing the necessary component replacements, preparations were made to restart the unit. During startup, it was noticed that all previously forced signals had been cleared from the force list. After reapplying the required forced signals, the unit started successfully.
During the synchronization process, the generator voltage displayed normally on the Mark V HMI. However, when the synchronization command was issued and the grid voltage signal was received by the Mark V system, both the generator voltage and the grid voltage readings began fluctuating simultaneously.
Voltage measurements were taken at the terminal blocks for both generator and grid voltage signal inputs. The measured voltages were approximately 100V AC on both sides and remained stable (no fluctuation observed). Interestingly, when either the generator or grid voltage signal wires were disconnected — leaving only one side connected — the remaining voltage signal became stable without fluctuation.
Based on the signal path of the generator and grid voltage measurements, several components were replaced for troubleshooting, including the PTBA and TCEB cards in the P core, and the TCCB card in the C core. The X, Y, and Z TCEA cards in the P core were also replaced, but the problem persisted.
Further tests were conducted by disconnecting the grid-side voltage signal wires and connecting the generator voltage wires to the grid-side terminals. Under this configuration, both voltage readings on the Mark V remained stable. Similarly, when the generator voltage signal was disconnected and the grid voltage signal was connected to the generator-side terminals, both voltages displayed stably without fluctuation.
Finally, both the generator and grid voltage signal wires were disconnected, and a relay protection tester was used as a signal source to inject voltage signals into the generator and grid voltage channels. Under this simulated condition, the voltages displayed in the Mark V system were stable and showed no fluctuations.
