Second Grid

AI Quick Summary

Current inverters injecting the current produced by renewables do not participate in the regulation and robustness of the grid. Furthermore, they are useless in the event of black-out. The "II Grid" project aims to change this through the emulation of inertia. Simulation proven control algorithms have been implemented in a prototype inverter, however a technological barrier has been reached with the available hardware. A new inverter using state of the art technology is necessary to overcome this barrier. One of the major challenges tomorrow’s electrical grid faces is the increase of renewable energy sources and their integration. The main issues is that they are not controlled by the grid operator, they inject their power on the grid when it is available and not necessarily when it is needed.The inverters currently used to connect and interface renewables to the grid are controlled in a grid following mode. With this basic type of control, the inverter injects current into the grid in phase opposition with the grid voltage to transfer the power produced. While this type of control works well, it has a major drawback; it is of no use in case of a blackout. To overcome this weakness and enable inverters to take part in the grid control a more advanced control technic as well as storage are required.This new advanced control is inspired by the way synchronous generators (SG), used to interface power plants to the grid, work. SGs can be readily connected to the grid and participate in the voltage and frequency control of the grid. The voltage control is achieved by acting on the reactive power transfer and the frequency control by acting the active power transfer. Furthermore, the mechanical inertia of the generator passively stabilizes the frequency when variations and disturbances occur on the grid. Inverters capable of generating their own grid exist, however because they impose their voltage and their frequency, they cannot be connected to the grid. Inverters capable of switching from grid following to forming their own grid also exist, however they do not switch modes without interruption.The idea developed in the project “Second Grid” is to make an inverter emulate the behavior of a synchronous machine. The algorithms developed integrate virtual inertia and droop control that allow theoretically to connect or disconnect several grid forming inverters, at the same time, without causing disruption on the grid. Furthermore, the droop control enables load distribution between the different units to occur naturally and without direct communication. Such capability would enable inverters to participate in the stability of the grid as well as greatly improve the robustness of local grids by giving them the capability to function autonomously in case of a blackout. So far, the algorithms have been tested in simulation and were implemented in a prototype inverter, however a technological barrier linked to the components and construction of the inverter has been met. To overcome this barrier, a new inverter must be developed to complete the proofing of the concept. This project falls in the focus of the project call because it has the potential to make the distribution grid much more robust. It also potentially enables small regions to function autonomously in the event of a widespread grid failure.Once the concept will have been proven, real life tests will need to take place on the grid with a pilot installation.

Project Idea Metadata

• Project Idea Name: Second Grid
• Date: 7/18/2022 8:46:25 AM
• Administrators:
  • Philippe Morey

Project Idea Description

One of the major challenges tomorrow’s electrical grid faces is the increase of renewable energy sources and their integration. The main issues is that they are not controlled by the grid operator, they inject their power on the grid when it is available and not necessarily when it is needed.

The inverters currently used to connect and interface renewables to the grid are controlled in a grid following mode. With this basic type of control, the inverter injects current into the grid in phase opposition with the grid voltage to transfer the power produced. While this type of control works well, it has a major drawback; it is of no use in case of a blackout. To overcome this weakness and enable inverters to take part in the grid control a more advanced control technic as well as storage are required.

This new advanced control is inspired by the way synchronous generators (SG), used to interface power plants to the grid, work. SGs can be readily connected to the grid and participate in the voltage and frequency control of the grid. The voltage control is achieved by acting on the reactive power transfer and the frequency control by acting the active power transfer. Furthermore, the mechanical inertia of the generator passively stabilizes the frequency when variations and disturbances occur on the grid.

Inverters capable of generating their own grid exist, however because they impose their voltage and their frequency, they cannot be connected to the grid. Inverters capable of switching from grid following to forming their own grid also exist, however they do not switch modes without interruption.

The idea developed in the project “Second Grid” is to make an inverter emulate the behavior of a synchronous machine. The algorithms developed integrate virtual inertia and droop control that allow theoretically to connect or disconnect several grid forming inverters, at the same time, without causing disruption on the grid. Furthermore, the droop control enables load distribution between the different units to occur naturally and without direct communication. Such capability would enable inverters to participate in the stability of the grid as well as greatly improve the robustness of local grids by giving them the capability to function autonomously in case of a blackout.

So far, the algorithms have been tested in simulation and were implemented in a prototype inverter, however a technological barrier linked to the components and construction of the inverter has been met. To overcome this barrier, a new inverter must be developed to complete the proofing of the concept. This project falls in the focus of the project call because it has the potential to make the distribution grid much more robust. It also potentially enables small regions to function autonomously in the event of a widespread grid failure.

Once the concept will have been proven, real life tests will need to take place on the grid with a pilot installation.

Current inverters injecting the current produced by renewables do not participate in the regulation and robustness of the grid. Furthermore, they are useless in the event of black-out. The "II Grid" project aims to change this through the emulation of inertia. Simulation proven control algorithms have been implemented in a prototype inverter, however a technological barrier has been reached with the available hardware. A new inverter using state of the art technology is necessary to overcome this barrier.