Normally, when the wind speed v>3m/s but not enough to drag the wind turbine to the cut-in speed, the wind turbine rotates freely and enters the standby state. In the standby state, except that the generator is not connected to the grid, the unit is actually in working state. At this time, the control system is ready to cut into the power grid. Once the wind speed increases and the speed increases, the generator set can be started. Generally, there are three ways to start a wind turbine:
(1) Self-starting. The self-starting of a wind turbine means that the wind turbine drives the generator to the rated speed without the assistance of other external forces under the action of natural wind. The early fixed-pitch wind turbines did not have the ability to start automatically, and the wind turbines had to be started with the assistance of the generator. At this time, the generator operated as a motor, which is usually called motor start. Until now, most of the fixed-pitch wind turbines still have a motor start function. With the continuous improvement of the aerodynamic performance of the blades, most modern wind turbines have good self-starting capabilities, generally when the wind speed v>4m/s, they can start automatically. During self-starting, after the system is powered on, the wind turbine will first perform a self-check, including the power grid, wind conditions, and unit parameters. After confirming that all parameters meet the relevant regulations and the system is fault-free, the safety chain is reset. Then start the hydraulic pump, the hydraulic system builds pressure, and the normal startup procedure is executed when the hydraulic system pressure is normal and the wind turbine generator has no fault.
(2) Local start. Local start has priority. When doing local start, the remote start function should be shielded. When the maintenance button of the engine room is in the maintenance position, it cannot respond to the start command.
(3) Remote start. Remote start is to send a start command to the single-machine central controller through the remote monitoring system. After the controller receives the remote start command, it first judges whether the system is in grid-connected operation or is being started, and whether the wind turbine generator is allowed to start. If it is not allowed to start, it will not respond to the command, and the command flag will be cleared at the same time. If there is a maintenance status command on the top or bottom of the electronic control system, the command will also be cleared without responding to it. The wind turbine can respond to this command when it is in the standby state and there is no fault, and execute the same startup procedure as the local startup. After the startup is complete, the remote startup flag is cleared.