HPU runs too often?

[Wt_eng]

Hi folks, first post here!

I'm looking into an issue on a wind turbine. The hydraulic power unit constantly flashes up on SCADA as running too frequently.

Previous investigations found that some of the accumulators were set below the pressure stated in the design documents. All accumulators were at the same pressure, so it seems that they were probably set this way during commissioning, but not documented anywhere.

I'm new to hydraulics, so need some pointers on some good background reading and some hints to what pressures the accumulators should be set at, and why they might have been set differently.

Your help is most welcome!

 

[HPost]

Your system will have set points for switching the pump on and off to charge the accumulators.

The recharge rate is a function of the leakage in the system. Backing off the pre-charge will allow them to store more oil, but if the system is leaking, that oil will drain off more quickly and the pump will come on more often to refill / recharge the system. It is this recharge frequency that your system is detecting.

Check you system for leaks. That is internal leaks across valves etc where the oil is escaping back to the reservoir. All valve leak to some extent, but if one valve is not shut or is compromised in some way, then the oil will drain from the accumulators.

Of course, this is very generic information. We don't know the accumulator volumes, or the pre charge pressure or how often is too often according to the monitoring system.

But you should check for leaks before doing anything else.