A key D&WS product is the Low Load Diesel (LLDTM). This Australian invention alters the operational characteristics of a conventional diesel engine so that it can run longer at low load levels, allowing more wind energy into the system. We use modern high speed electronically injected diesel generators which mean that power quality and step-load response is not compromised. Currently we are using the Detroit Series 60 range of engines and one of these is shown under test below in 2003.
Diesel generator sets must usually run at greater than 40% of their nameplate rating in order to avoid combustion related maintenance problems, particularly to the bore of the engine. When wind energy is available to a diesel power station, it is sometimes 'dumped' in order to maintain the diesel generator(s) above minimum loading. This can limit the amount of available wind energy that the system can utilise.
Diesel power stations also normally run with a level of spinning reserve which reduces the risk of blackouts following unforseen system problems. Combining this need with the minimum loading requirements is a major obstacle to maximising wind energy input to such systems.
D&WS staff examined this issue over many years and trialled a number of technologies to increase the amount of wind energy penetration. For example, we looked seriously at different battery and energy storage systems such as flywheels (see below) and trialled some of these at our real world test site at Denham, Western Australia. We also trialled a number of different control algorithms and platforms.
What was found from this testing was that many different technologies are possible but only a few work in isolated, remote areas. In such places, the technical skills available centred on diesel engines and it makes sense to limit the technology introduced to that which can be easily servcies and maintained, even if operators have a high turnover. Hence the LLDTM was developed.
On isolated system applications, the LLD TM is usually used in conjunction with what is termed a Dynamic Grid Interface (DGITM). This patented product allows a power system to survive large load rejection events and severe swings in wind turbine input even if the only fossil generation source is a Low Load Diesel operating at very low loads. The DGITM is explained more in the following link <DGI>.
In the Downloads section you will find more information about the use of Low Load Diesels and Dynamic Grid Interfaces. In particular, the paper from the 2003 Australian Wind Energy Association Conference and Exhibition (AusWEA 2003) has a section devoted to explaining how these products can be used.
The page on the Denham wind/diesel system also gives the actual system results from the installation of a Low Load Diesel, so you can see for yourself that they are very effective.