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Documents complementing Grid code specifications

Fingrid has collected on this page the necessary up-to-date instructions and documents that complement the Grid Code Specifications. Previous documents can be read in the Archive.

Specific study requirements for power park modules connected to converter-dominated areas
Unstable operation of power park modules can cause disturbances in grid voltage and lead to the disconnection of power park modules from the grid. The instability is caused by interaction phenomena arising from the existing control solutions of the converters that connect power park modules to the grid as well as inadequate performance during fault conditions, that occur in highly converter-dominated areas. For solar and wind power park modules connected to such areas, specific study requirements may be imposed when necessary. These requirements may require the power park module to have grid-forming (GFM) control capabilities. The facility owner may implement the required capabilities either in the converters of the power park module or by using separate stabilizing auxiliary equipment located within or near the power park module.

 

A webinar on the topic was held on Friday, 16 October 2026, from 13:00 to 14:00 (only in Finnish):

 

Tuning the voltage controllers of power park modules
Guidance on the tuning of voltage control for power park modules, and considering the Equivalent Short Circuit Ratio (ESCR) in plant design.

 

Specific study requirements for power park modules related to risk of subsynchronous interaction
The document (updated 11.2.2022) defines the requirements for protection, modelling, damping and instrumentation arising from the risk of subsynchronous oscillation (SSO) phenomena. Fingrid has published also a white paper, which explains the technical background of the phenomenon.

Placing a wind power plant near a power line
The statement describes the minimum distance between a wind power plant and a power line. (Only in Finnish)

Information to be provided during the preliminary planning (Stage 0)
In accordance with the grid code specifications for power plants and energy storage systems, the facility owner must arrange a kick-off meeting with Fingrid and the relevant network operator during the preliminary planning of the facility. This meeting will address the complience monitoring process and review the project's initial technical data and key design principles. The topics to be discussed during the initial meeting are compiled in the form "Stage_0_questionnaire," which the facility owner must complete and submit to Fingrid before the initial meeting

Cybersecurity survey for power plants and energy storage systems connected to the electric grid
Survey is needed as part of Grid Code complience process for B, C and D –type power plants and energy storage systems. For B, C and D type the survey needs to be completed before the interim operational notice describing how security is considered in the design. For C and D –type the survey needs to be completed also after the commissioning phase to describe the implemented solutions.

Assessment of Conditions for Participation in Reserve Markets from the Perspective of Fingrid's System Technical Requirements

This guidance document describes the conditions under which power generating facilities, energy storage systems, demand facilities, demand units, and HVDC systems connected to the Finnish power system may begin providing system services to reserve markets before the system technical requirements compliance verification process has been fully completed. The document presents the minimum requirements, required documentation, statements, and commissioning and verification tests applicable to different facility categories and reserve products. Its purpose is to ensure a consistent interpretation of the requirements and procedures among facility owners, point of connection network operators, and Fingrid. Document is only available on Finnish.

 

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