Cooling a wind turbine

A cooling system for a wind turbine, the cooling system comprising:

• a fluid circuit arranged to convey a working fluid to and from at least one component of the wind turbine to exchange heat between the working fluid and the at least one component;
• a main pump configured to circulate the working fluid around the fluid circuit;
• and
• at least one branch line connected to the fluid circuit, said at least one branch line comprising:
• an inlet arranged to receive working fluid from the fluid circuit;
• an outlet arranged to return working fluid to the fluid circuit;
• a branch pump arranged to pump working fluid through the at least one branch line from the inlet to the outlet;
• and
• a cooling device arranged to cool working fluid flowing through the at least one branch line,
• wherein the at least one branch line is devoid of a wind turbine component, spaced from the branch pump, that heats the working fluid flowing through the at least one branch line.

A cooling system for a wind turbine, the cooling system comprising:

• a fluid circuit arranged to convey a working fluid to and from at least one component of the wind turbine to exchange heat between the working fluid and the at least one component;
• a main pump configured to circulate the working fluid around the fluid circuit;
• and
• at least one branch line connected to the fluid circuit, said at least one branch line comprising:
• an inlet arranged to receive working fluid from the fluid circuit;
• an outlet arranged to return working fluid to the fluid circuit;
• a branch pump arranged to pump working fluid through the at least one branch line from the inlet to the outlet;
• and
• a cooling device arranged to cool working fluid flowing through the at least one branch line,
• wherein an entirety of the working fluid in the at least one branch line flows through the cooling device in the at least one branch line before being returned to the fluid circuit.