Monitoring the Coultershaw Hydro Generator
River level sensors around the hydro are used to control the power output of the generator and trigger a shut down in flood conditions. Real time data is shown below.
Controlling the Hydro
Water from the river above the hydro passes through a sluice to the penstock (the tank of water at the top of the Archimedes screw). The water then flows down through the screw releasing its potential energy until it reaches the pool below. The amount of power generated will be proportional to the head – the height drop between the penstock and pool. In cases of high rainfall the screw becomes partially submerged and eventually has to shut down. In periods of very low rainfall the power is reduced to ensure that an adequate supply of water passes down through the adjacent fish pass. A micro-controller (Raspberry Pi!) monitors the sensors and controls the sluice to ensure optimum power generation for the river conditions.
Unfortunately the River Rother is silting up quite quickly which reduces its ability to drain away flood water. Relatively small amounts of rain will raise the level in the pool and so reduce power generation.
Sudden changes in level seen on the graph above are caused by the manual opening and closing of the bypass sluice. If the river begins to flood upstream the sluices are opened – which shuts down the hydro – to balance the risk of flooding between upstream and downstream regions of the Rother.