Fire hazard analyses of typical oils in wind turbine nacelle based on single and composite indices

Fire response characteristics of three typical liquid oils (gear box oil, hydraulic oil, and transformer oil) in wind turbine nacelle were characterized by using the cone calorimeter experiments. Single indices (HRR, THR, SEA, RSR, TSR) of three liquid oils were analyzed at external radiant heat flux of 15.0, 25.0, 35.0, 50.0, and 75.0 kW/m2. Afterwards, composite indices (FPI, FGI, and SP) were calculated. These indices consist of an Indicator System. Results show that transformer oil can act as both a fire source and process fuel, emits smoke fast in initial and development stage; hydraulic oil keeps fire development and bring more fuels into burning, produces most amount of smoke slowly and reinforces overall opacity of a fire; gearbox oil is relatively inert in burning and can elongate fire decay stage, continuously emits thick smoke during a whole fire.