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In my plant (Oil & Gas), there is this scenario:
This is a captive power generation system (no grid connection). There are 3 GTGs (Gas Turbine Generators, rated 10 MVA each) supplying power to the plant in normal operation. And there is one small DG (Diesel Generator, rated 1 MVA) to supply power to facilitate black-start of GTGs and to power-up utilities like HVAC, lighting etc, when GTGs are not working.
During black-start, the DG is started and it supplies all the consumers (GTG auxiliaries) required for black-start and utilities like HVAC, lighting etc. Then, one of the GTG is started. Next, two sources of power (GTG and DG) need to be synchronized and plant load need to be transferred from DG to GTG so that DG can be isolated and switch-off and plant can resume normal operation using power from GTG.
Now, my query is: During synchronization of DG and GTG, which one of them should be considered as fixed power source and which one shall be regulated (V & f)? If we assume that running source shall be considered as fixed and incoming source shall be regulated then DG will be fixed source and GTG will be regulated. Is it acceptable to assume small 1 MVA source as a fixed reference and regulate & synchronize big 10 MVA source with it? I am not feeling comfortable with this because in my personal experience, I have always seen smaller source (DG) being regulated and synchronized with bigger source (GTG) without considering which one is running source and which one is incoming source. In fact, regulating GTG and trying to synchronize it with small DG seems like a mouse is being regulated and synchronized with an elephant.
Please share your experiences and knowledge on the matter to help me out.
Thanks & Regards,
Sk
This is a captive power generation system (no grid connection). There are 3 GTGs (Gas Turbine Generators, rated 10 MVA each) supplying power to the plant in normal operation. And there is one small DG (Diesel Generator, rated 1 MVA) to supply power to facilitate black-start of GTGs and to power-up utilities like HVAC, lighting etc, when GTGs are not working.
During black-start, the DG is started and it supplies all the consumers (GTG auxiliaries) required for black-start and utilities like HVAC, lighting etc. Then, one of the GTG is started. Next, two sources of power (GTG and DG) need to be synchronized and plant load need to be transferred from DG to GTG so that DG can be isolated and switch-off and plant can resume normal operation using power from GTG.
Now, my query is: During synchronization of DG and GTG, which one of them should be considered as fixed power source and which one shall be regulated (V & f)? If we assume that running source shall be considered as fixed and incoming source shall be regulated then DG will be fixed source and GTG will be regulated. Is it acceptable to assume small 1 MVA source as a fixed reference and regulate & synchronize big 10 MVA source with it? I am not feeling comfortable with this because in my personal experience, I have always seen smaller source (DG) being regulated and synchronized with bigger source (GTG) without considering which one is running source and which one is incoming source. In fact, regulating GTG and trying to synchronize it with small DG seems like a mouse is being regulated and synchronized with an elephant.
Please share your experiences and knowledge on the matter to help me out.
Thanks & Regards,
Sk