TURBINE TECHNOLOGY AND SEDIMENT CONTINUITY
If a hydroelectric power plant is present at the dam site, questions often arise regarding the protection of the discharge elements, especially the turbines. These can usually be answered simply:
Almost all turbine water contains sediment. Nevertheless, abrasion is not observed at most turbines. This is due to the usually low sediment content of the turbine water. Increasing the sediment content by a few percent does not change this. The maximum grain size of the transferred sediment can be adjusted in our technical solutions, so that the turbine is protected against excessively large grains. Only in the case of waters with a considerable sediment content can abrasion, which then occurs at the turbines anyway, be increased. Even increased turbine abrasion, however, is much more cost-effective than conventional sediment dredging measures. In addition, modern coating systems provide good protection against abrasion. If locally appropriate, sediment can also be transferred around a dam and only added back to the water body downstream of the power plant. We will be pleased to advise you.
Main shaft seal
Again, almost all power water contains sediment anyway. However, the main shaft seal is very sensitive to particles. For this reason, most shaft seals are equipped with a clear water flushing system that keeps the seal free of foreign particles. This means that wear on the main shaft seal is completely independent of the sediment content of the engine water. Turbines that do not yet have a clear water flushing system can usually be easily retrofitted with this option.
Power plant inlet
The power plant screen is not blocked, as depending on the sediment load and grain sizes, the settling area can also be arranged behind the screen or even behind the dam.
In the case of pumped storage power plants with river impoundments as lower reservoirs, the sediments deposited in the upper reservoirs have passed the pump turbines before.
However, it should be noted:
Because of the high head water velocity, Pelton turbines should be considered separately, as they are particularly susceptible to particle loads. The same applies to Francis turbines with a head of well over 200 m.