Challenge

In 2016 Fritz Schur Energy took on the assignment of customizing a retrofit solution for an international wind farm. The farm had experienced continuous turbine stops due to overheating and high pitch oil tempera­ture in their machines caused by very turbulent wind conditions. This was not a typical operational failure seen in numerous farms, but nonetheless, a failure that had a recurring negative impact on the farm’s efficiency and production.

High hydraulic oil temperatures in pitch systems represent a hazard to the proper functioning of the hydraulic components, mainly seals and pumps, and decrease the efficiency of the system by allowing higher internal leakage in the components. Normally, under high oil temperature conditions, the turbine triggers an emergency stop at a reasonable level to protect the system. Ideally, the system should be properly designed to maintain acceptable oil temperatures in operating conditions.

Solution

To solve the problem, Fritz Schur Energy installed our Oil Conditioning Unit (OCU), which ensures a much more narrow operating temperature of the oil, avoiding overheating and offering cleaner oil at the same time. A unique retrofit solution that Fritz Schur Energy developed specifically to tackle challenges in keeping the pitch oil cool and clean in turbines with high pitch activity, as well as periods with very low wind.

Results

After fitting the OCU on one of the farm’s turbines, the farm experienced no downtime due to the high pitch oil temperature in that particular turbine.

However, the OCU also has an added benefit. It is a well-known fact that oil wears much faster in high temperatures than in low temperatures. So, avoiding high temperatures is not only beneficial in turbines with many overheating stops; it is also beneficial that the oil is mostly 50-60 °C / 122-140 °F and causes no stops. Data shows that for every 10 °C / 50 °F increase in temperature, the lifetime of the oil is cut in half. Removing high-temperature situations completely will therefore have a positive impact on the maintenance of the entire hydraulic system, e.g., fewer oil replacements, improved lubrication performance, and less wear.

In short, the OCU extended the lifetime of the oil, as well as the lifespan of the entire hydraulic system.

Other benefits include:

• An improved lifetime of all components in the hydraulic pitch system
• An improved lifetime of hydraulic oil
• Efficient continuous offline filtration of the hydraulic oil
• Efficient continuous cooling of the hydraulic oil – controlled by an independent thermostat
• Higher uptime and increased earnings