Telecommunications companies play an essential role in keeping Australia (and the world) connected. They are often solely responsible for maintaining critical infrastructure systems such as emergency .....
Small wind turbines such as our Hyland 920 are often installed in remote locations that are very difficult to access. It is a design requirement for these turbines to be able to withstand any environmental conditions that are thrown their way, without the need for human intervention – although this is often where small turbines come unstuck.
In this article, we will highlight certain weather scenarios and discuss our MkII controller’s response to these conditions. This real-world data is visible for Diffuse Energy customers through our Remote Monitoring Dashboard.
Our MkII controller is limited to a 12 A output to the battery. Note that this current limit is conservative to ensure longevity of our system. For the turbine to continue operating in high-wind conditions, excess power is sent to the dump resistors which sheds some power to allow the turbine to continue operating. The image below shows wind speeds hovering around 70 km/h. There is 12.18 A going to the battery system (our system allows transient peaks above 12 A for very short periods of time) and 3 A being diverted to the dump resistors.
As mentioned above, our Hyland 920 system is limited to a 12 A output to the battery. For our 48 V system, this current level is reached at approximately 75 km/h (dependent on a few variables such as battery levels, ambient air temperature and pressure) and this is therefore the maximum operating wind speed. For our 24 V system, the maximum operating wind speed works out to be approximately 55 km/h.
The different maximum wind speeds for different system voltages are governed by the following equation: power = voltage x current.
The image below demonstrates the speed at which our MkII control system detects a large gust of wind (by monitoring the turbine’s RPM – not wind speed) and quickly diverts some current to the brake resistors to slow the turbine.
The instant that the wind speed approaches the 75 km/h theoretical maximum, the controller immediately commands the turbine to shut down (under 5 ms response) and the turbine takes less than 0.25 sec for the blades to slow to 50 rpm (from 1300 rpm). At this point the controller no longer transmits any power, thus protecting itself. Additionally, the turbine blades are far less likely to be damaged by any flying debris at low rpm.
The image below shows our 48V system shutting down after a gust of wind exceeded the 75 km/h limit. Note that there is a 15-minute timer before the system attempts a restart – this is to prevent frequent stopping and starting between gusts. This cool-down period has since been reduced to 5 minutes as we continue optimising our systems for maximum power output. The turbine is restarted with 100% brake on the dump load resistors and the response of the turbine is carefully monitored to ensure a ‘safe’ return to service. This all happens very quickly with the turbine reaching operating speed in well under a second.
The next image demonstrates the Hyland 920 system stopping during a prolonged high-wind event. The system then restarts briefly during a lull before having to shut down again as the high-winds return. Gusts of up to 86 km/h were recorded from our on-site weather station.
The image below shows our 24 V system efficiently switching off and on as the wind speed hovers around its limit of 55 km/h. As explained previously, the 24 V system is also limited to 12 A and therefore is limited to a lower wind speed as governed by the equation (Power = voltage x current).
Our Hyland 920 also features a smart battery management system to optimise the power output as the battery approaches 100% charge. As can be seen below, the controller applies a higher current to the turbine brake resistors as the battery gets closer to ‘full charge’ – once reached, the system eventually shuts down to prevent over-charge. By braking as the battery approaches full, the turbine is allowed to continue at a lower current output which gives the benefit of trickle-charging the battery. Note that the high braking current is only required due to the high-wind conditions in the image below, in low-wind conditions the braking current would be negligible.
Once the system has shut down, it will not restart until a 1 V battery voltage drop is detected to prevent frequent stopping and starting of the system.
In addition to the above safety features, our MkII controller also monitors its internal temperature during critical conditions and derates or shuts down accordingly. The Printed Circuit Board (PCB) also has a dedicated layer of copper purely for cooling the electronics. We implemented these safety measures to further improve the controller’s reliability when used in remote locations with elevated temperatures and high-winds, such as central Australia. Interestingly, we haven’t recorded a shut down due to temperature in the field to date. We have pushed our MkII controllers to the limit on our custom test-rig and we’re confident that they will continue to work as intended during extreme conditions.
Our Hyland 920 wind turbine and MkII controller have undergone an incredible amount of development and testing to produce what we believe is the most efficient, reliable and safest small wind turbine on the market. If you have any questions on the finer details of Hyland 920 system, please email us at sales@diffuse-energy.com and we will gladly assist you.
.svg "Logo white (1)")
