Pitch control of wind turbine blades in a standby mode

A non-transitory computer readable medium storing program code instructions for implementing an operation of a wind turbine generator (WTG) comprising a pitch control system, the operation comprising:

• a) operating the WTG in a normal mode while the WTG is connected to an external grid;
• b) controlling a pitch angle of blades of the WTG using a normal pitch control mode while the WTG is operating in the normal mode;
• c) detecting a grid loss;
• d) operating the WTG in a standby mode during the grid loss, wherein in operating the WTG in the standby mode during the grid loss, the WTG is operated to generate backup power to power one or more sub-systems of the WTG and/or to charge an energy storage system associated with the WTG;
• and
• e) controlling the pitch angle of the blades in dependence on a monitored speed parameter of the WTG using a standby pitch control mode different to the normal pitch control mode while the WTG is operating in the standby mode, wherein the standby pitch control mode is less responsive than the normal pitch control mode such that power consumption of the pitch control system is reduced when the WTG is operating in the standby mode, and
• wherein a lower pitch rate is applied when adjusting the pitch angle of the blades when the WTG is operating in the standby mode compared to when the WTG is operating in the normal mode.

A controller, comprising:

• an I/O interface configured to be coupled to a wind turbine generator (WTG) comprising a pitch control system;
• a non-transitory computer readable medium storing program code instructions;
• and one or more processors which, in executing the program code instructions, are configured to perform an operation comprising:
• a) operating the WTG in a normal mode while the WTG is connected to an external grid;
• b) controlling a pitch angle of blades of the WTG using a normal pitch control mode while the WTG is operating in the normal mode;
• c) detecting a grid loss;
• d) operating the WTG in a standby mode during the grid loss, wherein in operating the WTG in the standby mode during the grid loss, the WTG is operated to generate backup power to power one or more sub-systems of the WTG and/or to charge an energy storage system associated with the WTG;
• and
• e) controlling the pitch angle of the blades in dependence on a monitored speed parameter of the WTG using a standby pitch control mode different to the normal pitch control mode while the WTG is operating in the standby mode, wherein the standby pitch control mode is less responsive than the normal pitch control mode such that power consumption of the pitch control system is reduced when the WTG is operating in the standby mode, and
• wherein the monitored speed parameter is monitored at a lower frequency when the WTG is operating in the standby mode compared to when the WTG is operating in the normal mode.