Automatic Rebalancing of Radial Gates of the Spillway Dam in Cameroon

One of the problems facing hydroelectric plants is the imbalance of radial gates of the spillway dam. This imbalance causes the deterioration of lateral guiding seals, the deterioration of thermal relays, the deterioration of motors, the rupture of chains and the deformation of radial gates slides. This results in higher maintenance costs. The most frequently used method for rebalancing is the manual method, acting on the brakes. It is not effective in the sense that it waits for the adverse effects of imbalance to occur before it is started and is very limited. In order to avoid the harmful effects of the imbalance of radial gates, where each bank is controlled by a mechanical winch, we have set up a methodology for their automatic rebalancing. The steps of the automatic methodology are; the determination of the maximum permissible unbalance, the determination of the pulse generation frequency for the choice of the input module type of the PLC (fast input or not), the determination of the relation between the number of pulses generated by the encoder and the vertical position on each side of the gate. The results obtained after application in the case of a spillway dam in Cameroon are as follows: the maximum allowable imbalance is is 0.052 m, the frequency of generation of pulses by the encoder is 3.18 Hz. Hence the determination of relationships h_B= 〖0.005 N'〗_impduring the ascending phase and h_B= 〖h'〗_B- 〖0.005 N'〗_imp during the descending phase, with the number of pulses generated by the encoder (N_imp) of the left bank and the vertical position of the left and right side of the radial gate.