We support the integration of microgrids through an optimal control strategy

The use of renewable resources under the microgrid approach, for decentralized electricity production, is an active field, with an accelerated development at the international level. At the same time, microgrids are emerging as a valuable technology for future power supply systems.

We identify the best technical solution, suitable for each application and analyze the funding sources

The Smart Microgrid Controller project (project ID 2020/505837), carried out through the Norwegian funding program 2014 – 2021 within the Green Industry Innovation, Blue Growth and ICT Program Romania, practically addresses the issue of developing a smart microgrid. The solution includes photovoltaic panels with an installed power of 120 kWp, two storage systems of different capacities and manufacturer (40 kWh and 56.3 kWh that allows observing the behavior and how to be adjusted in such a solution, chosen for demonstration purposes), the inverter that allows switching between different elements and a 120 kVA gas generator. The microgrid serves the Monsson office building.

By implementing this project, SIS aims to increase the number of microgrid systems implemented at national level, supporting sustainability in the use of green technologies by increasing efficiency in local energy production and use, facilitating direct transactions between production and consumer.

Choose to implement a turnkey microgrid project – design, execution, support – with SIS SA

SIS has developed an intelligent controller on a redundant Siemens S7-1500 platform, which will ensure the monitoring and control of the elements so as to efficiently use the available generation and storage resources and optimize the amount of energy taken from the national network according to cost. In the Monsson case study there are several communication protocols, so it is not a closed system, which gives the redundant controller flexibility between interfaces and to increase system reliability, but due to the fact that they were common protocols, information connection does not was a challenge.

Regarding the mode of operation, there are two types, which SIS has implemented in the control network of the microgrid:

  • Network Connected
  • Islanded

Network Connected

When the photovoltaic power generation capacity is higher than the consumer’s electricity consumption, a message will be sent to the batteries and the status will be queried, so that if it is discharged, it will start the storage process. But if the battery is charged (enters standby) it will switch to the insularized module or an energy equal to the difference between production and consumption will be injected into the network. When the fleet of photovoltaic panels will produce less energy than the energy consumed and the battery is discharged, then it is necessary to buy from SEN a quantity prioritizing battery charging and production equal to the difference between consumption and production, to which is added the amount of energy. from batteries. If the batteries are charged, the purchased energy will no longer include the necessary storage.

When the power in the panels is zero and the batteries are discharged, the mains batteries are recharged, but if there is enough power in the batteries, the battery consumption will be prioritized.


In this way it is no longer the case to exchange energy with the grid, but it is considered that the microgrid produces energy (from the generator and from the panels) in the following: When the power provided by the park is greater than the power consumed by the building and the batteries are charged will switch to “stand by” mode, if they are downloaded they will be loaded. However, if the power is less than the energy consumed and the batteries are discharged, it will be necessary to switch to the mains; When there is no energy produced from the photovoltaic panels, the batteries are used to power the building.

Contact a SIS technical expert to evaluate the performance of a microgrid for any type of building and location free of charge.

If you have questions about our project or the possibility of replicating it according to your needs, please contact us at sis@sis.ro