Schwatzernov
Electrical
- Sep 5, 2006
- 47
Hi,
I have question related to transient stability for 4x GTG(GE frame 6B,40 MW each. There are 4 x GTGs operating connected with utility power grid at 115kV. During normal operation, power plant has captive loads at 50 MW and the surplus will be exported to grid. When line to utility is tripped, plant becomes island. To have plant stable after islanded, 2xGTGs is tripped and left two GTGs operating, one GTG is set to isochronous mode and the other is droop. The GTG uses GGOV3 model in Etap which is valid for Mark-V controller.
The problem is that when I simulate transient stability using ETAP 7.5, I found that one GTG(GTG#1) does not change to isochronous mode and seems that both GTGs are still operating in droop mode since these two GTGs are operating by sharing their loads equally. The other strange is that after plant is stable at steady-state, frequency does not change to nominal 50Hz but still stay at approx. 50.65Hz.
How to get Etap change one GTG from droop to isochronous ? I found that if I change the governor model from GGOV3 to the simple GT model, it works and one GTG is changed to isochronous mode.
The herewith enclosed are the result of simulation using GGOV3 governor model.
Appreciate any advice on this issue.
Thank you,
I have question related to transient stability for 4x GTG(GE frame 6B,40 MW each. There are 4 x GTGs operating connected with utility power grid at 115kV. During normal operation, power plant has captive loads at 50 MW and the surplus will be exported to grid. When line to utility is tripped, plant becomes island. To have plant stable after islanded, 2xGTGs is tripped and left two GTGs operating, one GTG is set to isochronous mode and the other is droop. The GTG uses GGOV3 model in Etap which is valid for Mark-V controller.
The problem is that when I simulate transient stability using ETAP 7.5, I found that one GTG(GTG#1) does not change to isochronous mode and seems that both GTGs are still operating in droop mode since these two GTGs are operating by sharing their loads equally. The other strange is that after plant is stable at steady-state, frequency does not change to nominal 50Hz but still stay at approx. 50.65Hz.
How to get Etap change one GTG from droop to isochronous ? I found that if I change the governor model from GGOV3 to the simple GT model, it works and one GTG is changed to isochronous mode.
The herewith enclosed are the result of simulation using GGOV3 governor model.
Appreciate any advice on this issue.
Thank you,