Performance Analysis of Frequency Governor Controllers under Implementing Free Governor Mode Operation in the Bangladesh National Grid

Grid frequency is a critical parameter that must
be maintained within an acceptable range to ensure the re-
liability, stability, and economic operation of modern power
systems. Free Governor Mode Operation (FGMO) has gained
significant importance in Bangladesh for providing primary
frequency response and enhancing grid resilience under varying
load conditions. This paper presents a performance analysis of
frequency governor controllers operating under FGMO using
operational data collected from Chandpur Power Generation
Limited (CPGL). The study investigates governor droop charac-
teristics, frequency regulation mechanisms, and the operational
differences between FGMO and conventional fixed power mode.
A mathematical framework based on droop control is developed
to describe the relationship between frequency deviation and
active power response. Experimental results obtained from a
one-hour FGMO field test demonstrate stable system operation
with a 4% governor droop setting and an 85% nominal engine
setpoint, maintaining the grid frequency within 49.54–50.58 Hz
while producing 60.48 MWh of energy with a net heat rate
of 8078.29 kJ/kWh. Comparative analysis shows that although
fixed power mode offers slightly higher fuel efficiency under
high loading conditions, FGMO significantly improves frequency
regulation, load sharing, operational reliability, and overall grid
stability. The results indicate that widespread implementation
of FGMO can reduce frequency excursions, minimize blackout
risks, facilitate the reliable integration of future renewable energy
resources, and support compliance with international primary
frequency response standards in the Bangladesh National Grid.
Index Terms—Bangladesh National Grid, Free Governor Mode
Operation (FGMO), Frequency Control, Governor Droop Con-
trol, Grid Stability, Primary Frequency Response.