The ongoing energy transition presents a range of challenges,

from long-term planning to short-term power system

stability. One key issue is the increasing penetration of

inverter-based resources, particularly as synchronous generators

are phased out. Grid-forming inverters offer a promising

solution to this challenge, as they can replace traditional

generators and provide grid-forming capabilities. However,

their dynamic behavior exhibits significant differences, particularly

in the design of the current-limitation strategy, which

should result in improved support and enhanced power system

stability. As a result, grid codes are evolving to address these

challenges.

Like all grid-connected devices, grid-forming inverters must

comply with grid codes to ensure stable power system operation.

This paper focuses on the validation of a novel

control strategy for current limitation during fault. This paper

focuses on the validation of a novel control strategy for current

limitation during fault disturbances. The validation is carried

out against RTE’s LVRT requirements and the ENTSO-E

report “Grid Forming Capability of Power Park Modules.”

The

proposed control approach is based on the Virtual Synchronous

Machine concept and does not rely on an underlying current

control loop. Instead, current limitation is achieved through

voltage limitation within the proposed scheme. Crucially, the

inverter maintains its grid-forming function even during fault

conditions as required by grid codes. The control scheme does not make use of a current control loop

under normal operation. Furthermore, the control suppresses

changes in frequency during and after the fault in contrast to

others, where the current limitation degraded transient

stability of the inverter or led to non sinusoidal fault current.

Due to the delay in the RfG v2 connection code, many

TSOs have launched consultation processes to require gridforming

(GFM) capability for BESS units and power park

modules, as is the case for Red El´ectrica, RTE, and Elia. Other

TSOs have already incorporated GFM requirements into their

grid codes, including Finland, AEMO as well as NGESO.

Additionally, guidelines for Germany have been published by

VDE FNN.

The LVRT requirements from ENTSO-E specify constraints

on current rise time and settling time at the onset

of a fault. RTE complements these requirements by imposing

additional criteria on active power recovery following fault

clearance . Both organizations assess the active-to-reactive

power ratio during a fault in the same manner.

To validate our approach, we conduct Electromagnetic Transients (EMT) simulations in

MATLAB/Simulink, demonstrating the method’s efficacy in

maintaining compliance with grid codes while ensuring system

stability. Our findings contribute to the ongoing discourse on

optimizing inverter technology for a reliable energy transition.