We would like to share some interesting projects we have been working on over the past few months. Our blog has been rather dormant as we have been extremely busy with new and existing clients - and we will try to do better, promise!
Off grid street light and pumping system
This project is interesting because it integrates several components together to form a complete monitoring and control system. A lithium battery bank of 48v is connected to a Victron inverter and solar charge controller. A Sundrax street light controller is connected to a string of 10 street lights over powerline communication, and bridged to Wattmon via Modbus RTU. The Victron is connected to Wattmon via RS232 for monitoring and via a digital output to force charge from the grid if and when necessary. A vortex filtration pump is also controlled via Wattmon at specific times of the day when energy is available. An AC power meter is also connected over Modbus RTU providing a comprehensive overview of the entire system. What makes this project unique is that it seamlessly bridges components that would not normally work together and provides a smart platform that helps optimise the use of renewable energy while at the same time ensuring the overall health of the batteries. We have also integrated it with a university project focussed on weather prediction, and it regularly updates its run schedules based on data from their engine.
Remote Power Monitoring
We have worked together with a multinational power company to provide a remote view of a 250MW power plant using Wattmon. One wattmon device at the power plant collects active power values from a meter and pushes it every 15 seconds to a second wattmon installed at the main headquarters. This data is then shown on a large 4 digit display in the control room allowing for immediate responses to anomalies. We achieved this using MQTT and both devices are connected via 3G dongles making this type of solution truly portable.
Power control with Multiple Diesel Generators
A one megawatt power plant installed at a factory provides fuel saving when one or more diesel generators are running. The challenge with a diesel generator is to ensure that a certain load is always present to prevent tripping the system, especially when this is used in a factory where certain processes require uninterrupted power. The additional challenge in this project is that we had to monitor 4 diesel generators and set the solar production levels to match the acceptable limits. Each genset had a different power rating. We also implemented dynamic power factor correction at the inverter to increase the overall efficiency.
Zero Feed - The Why
In India many states experience frequent and crippling power cuts. Solar rooftop systems are springing up everywhere, from small residential houses to large factories in attempt to save costs and in so doing reduce carbon emissions. Many states have not modified their policies yet to allow feed in, which in turn means that all solar generation needs to be used within the premises. This is fine when the installed capacity is much less than the average load, but when a larger solar plant is installed problems can and will occur when loads are less in peak solar hours and during weekends.
Zero Feed - The How
A power meter is installed at the incomer of the building, and is used as a reference to determine the active power load on the building. This meter needs to be able to communicate with Modbus RTU. The Wattmon device is connected to both the power meter and the inverters. It will regularly poll the power meter to determine the active power. As it reaches a threshold value that can be set by the user, it will ramp down the output power on the inverters using power control commands on Modbus RTU. This will effectively limit the amount of generation dynamically so that exporting of power does not happen.
DG Protection - The Why
Diesel generators bridge the gap during power cuts and in some locations they are used 24/7. When coupled with solar grid tie inverters, a saving of fuel can be achieved. However, it is important to balance the amount of solar power generated so as not to trip the genset, which effectively means you need to maintain a certain minimum load on the generator at all times.
DG Protection - The How
A power meter is installed on the output of the genset, and connected to the Wattmon in the same way as with zero feed. The Wattmon monitors the energy generated and if it drops below a set point, it will reduce the power of the inverters so as to ensure that the generator does not trip.
Both these systems can be installed at the same site by using two power meters and some software customization which will allow the set points to vary based on whether grid energy is available or whether the system is running on the generator.
For more details on our system, please contact us.