# Commission Regulation (EU) 2017/1485 of 2 August 2017 establishing a guideline on electricity transmission system operation (Text with EEA relevance), Article 109: Reactive power ancillary services

Extent: E+W+S+N.I.

1. For each operational planning time-frame, each TSO shall assess, against their forecasts, whether its available reactive power ancillary services are sufficient to maintain the operational security of the transmission system.
2. In order to increase the efficiency of operation of its transmission system elements, each TSO shall monitor:
(a) the available reactive power capacities of power generating facilities;
(b) the available reactive power capacities of transmission-connected demand facilities;
(c) the available reactive power capacities of DSOs;
(d) the available transmission-connected equipment dedicated to providing reactive power; and
(e) the ratios of active power and reactive power at the interface between the transmission system and transmission-connected distribution systems.
3. Where the level of reactive power ancillary services is not sufficient for maintaining operational security, each TSO shall:
(a) inform neighbouring TSOs; and
(b) prepare and activate remedial actions pursuant to Article 23.

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Source: https://www.legislation.gov.uk/eur/2017/1485/article/109 (the official version)
Page: https://openlegislation.uk/eu-regulation-2017-1485/article-109
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.