Dear Sir,

We have Speedtronics Mark-IV & frame -VI machine with natural gas. Can you please explain the Part load in detail with importance of it?

Base load is when your TTXM = TTRX. Your FSR will be selected to FSRT.

Preselect load is your turbine load will be equal to Your set point. TNR(load) will be the governing point for FSR through FSRN.

Please correct me if it is required.

As I try to understand from logic elementary, when the Base load is selected by operator and FSRT is selected as FSRMIN and governs the load, that becomes base load. Now if your TTXM is below TTRX and FSRMIN is FSRN, the control is "PART LOAD CONTROL"

With Thanks in advance

 

By definition, Base Load is full load. Anything less (preselected load, manual setting) is partial load. If you have Peak load capability, that would be a higher load than base, but that takes life out of the turbine.

 

As otised says, the simple answer is that 'Base Load' is defined to be full load ("rated" load as affected by ambient and machine conditions) and anything else between generator breaker closure and Base Load is defined to be 'Part Load'. If the unit is being operated at less than Base Load with Pre-Selected Load Control enabled, the <OPM> (the Mark IV operator interface module CRT) will display 'Preselect Load', but it's still 'Part Load' because it's less than Base Load.

If you watch FSRT (CPD-Biased Temperature Control FSR) and FSRN (Speed Control FSR) as you load the machine, you will see that FSRN increases proportionally as load increases. At some point during the loading, FSRT will start to decrease, FSRT is a function of the exhaust temperature control reference, TTRX. As CPD increases as the unit is loaded, TTRX will decrease and that will cause FSRT to decrease.

Both of these FSRs feed into the FSR Minimum Select "Gate", or "block", and when FSRT is less than FSRN then FSRT will be the signal that is converted to FSR and is controlling the position of the fuel control valve.

When Base Load is selected by the operator, FSRN is automatically increased at a controlled rate and the machine is loaded. As the machine is loaded, CPD will increase and TTXM (the "median" exhaust temperature) will also increase.

As the unit approaches full output, FSRN and FSRT will be converging (FSRN will be increasing and FSRT will be decreasing). Also, TTXM will and TTRX will be converging; TTXM will be increasing and TTRX will be decreasing.

When TTXM and TTRX are equal, FSRN and FSRT will be equal, and the unit is said to be at "Base Load".

FSRMIN is a separate signal and should not be confused with Minimum Select FSR Gate/Block. (FSRMIN is a value which is set to try to prevent flame-out on a load rejection event.)