Research on Installing Air Gap Monitoring Device Based on 4D Millimeter Wave Technology

In terms of hydro-generator sets, it is difficult to perform the air gap monitoring in the process of rotor hoisting during the installation and construction or maintenance of the hydropower plant, If the air gap distribution is not uniform, the distance between the armature and the magnetic pole will be inconsistent, making the magnetic flux distribution is uneven, resulting in the output power instability, which will affect the load of the power grid; The uneven air gap will also affect the load capacity of the generator; the uneven air gap will also lead to the noise during the generator operation; When the uneven air gap will make the motor produce uneven electric field and current distribution, leading to the armature and magnetic pole produce excessive heat, thus increases the motor temperature and reduces the life of the motor. It has a great impact on the economic benefits of hydro-power plants and the local people. In view of the limitations, a method based on 4D millimeter wave radar is proposed. First, 4D millimeter wave radar was used to scan the fixed rotor to obtain point cloud data, and the heterogeneous data fusion analysis method based on homogenous sensor was used to process the data. Finally, construct the air gap model of point cloud rotor and conduct the distance analysis. This method can monitor the air gap in real time during the rotor installation. The 4D millimeter wave radar equipment has the advantages of easy layout, easy operation and high accuracy, which greatly reduces the workload of maintenance operators, greatly shortens the installation time, and saves precious time for the lifting of the generator rotor.