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Off Grid Energy Independence
Posted on May 15, 2018 by  & 

Optimising management of microgrids

Guillermo Domínguez, Catalonia Institute for Energy Research (IREC), obtained his Bachelor's Degree and his Master's Degree in Industrial Engineering from the School of Industrial Engineering of Barcelona (ETSEIB) at the Polytechnic University of Catalonia (UPC). He developed his Bachelor's thesis in 2015 at Catalonia Institute for Energy Research (IREC) on improving Data Centre efficiency. In 2017, he developed his Master's thesis at Technical University of Denmark (DTU) on frequency control in high RES dominated power systems without must-run units. In October of 2017, he joined IREC as a Project Engineer and his research interests are smart SCADA applications and smart grid control strategies for RES integration. At ICREN Barcelona April 2018 he spoke on microgrid optimisation with PV penetration and Storage using his La Graciosa case study.
He said that future power systems with high penetration of renewable generation and ICT will facilitate better controllability and observability of the grid. However, new challenges for low voltage distribution networks have arisen where the increasing distributed generation is mainly PV installed on the roofs of buildings. This is variable, generating disturbances in the network. Microgrid islanding is ideal when installing new technologies because weak grids and the penetration of PV will lead to bidirectional power flows at distribution level, necessitating smart control.
He presented an innovative tool for the DSOs to monitor and manage grid operation. In the near future, both distributed renewable generation and client's flexibility will increase, he believes. New monitoring and control tools for DSOs will be essential. Furthermore, the grid operation optimization is needed to accommodate the intended DER installations and active participation of consumers' flexibility services in markets will ensure system efficiency. This tool was tested on "La Graciosa" minigrid, one of the Canary Islands, to show its benefit. The minigrid includes HESS, PV generators and controllable/uncontrollable loads as well as some power analysers installed along the lines to monitor it.
His research tool comprises both an OPF and a SCADA. The former determines the best operating level for each generator or storage in the microgrid to meet demand and reduce losses maximizing
PV penetration. By using the data obtained including PV prediction and HESS status, the OPF can set the current and predict future states by means historical values.
A SCADA application was also designed to manage the minigrid in real time. The SCADA centralizes all the data and stores it to feed the OPF model with real time values, collects the calculated setpoint and stablish the communications between all the devices installed.
His conclusions were:
  • The worst average error of the optimizer is 7%, considered admissible due to the forecast uncertainties.
  • Low level controls (real-time) are needed to rectify the optimizer error between the prediction and the real status.
  • The optimizer is highly dependent on the aggregation of the grid, the measure points and the PV and Demand forecast.
  • The users follow the active power restriction 87-91% of the time.
  • In a future local market, the users may be bonified or penalized for such support.
  • The SCADA allows to operate and manage remotely the equipment in case of failure. That is a great new asset for locations where there is no technical support placed.
Challenges and limitations were seen to be:
  • Communication problems due to the 3G connection between the equipment.
  • Simplification of a LV distribution grid.
  • Obtain an accurate PV and Demand forecast.
  • 3-phase Balanced system assumed
Future work is suggested as:
  • Emergency state demonstrator.
  • Improving the system for island operation.
  • Increase the number of smart meters to show its dependence on the optimization.
  • Expand it to 3-phase unbalanced operation
  • Modify 3G to another more stable communication system
  • Integrate more RES

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Posted on: May 15, 2018

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