Introduction: The increasing penetration of convertor fed generation leads to a variety of problems such as low system inertia, increased rate of change of frequency, loss of synchronising torque, high frequency instability and controller interaction.

Grid forming converter technology enables renewable generation to behave in a similar manner to conventional generation and hence offers a method of achieving higher renewable penetration in the energy market. PowerFactory Simulations in innovation project NIA_NGET0106 showed it is theoretically possible to run the GB transmission system with 100% renewables using grid forming converter technology.

The key aim of the proposed work is to inform National Grid of realistic ways that a power-park owner/operator might achieve levels of Grid-Forming capability compliance, through mixes of different device types placed in parallel as “hybrids”.

Objectives: The objectives of this project are to:

• Understand the behavior of hybrid grid forming convertors seen from the point of connection
• Understand any risks or issues of the design and application
• Provide evidence either to support mandatory changes in converter fed generation performance, e.g. through Grid Code and/or Distribution Code modifications, or to support development of balancing service markets to value the abilities of grid forming converter generation.