Article 59 Limited operational notification for HVDC systems/derogations
United Kingdom
HVDC system owners to whom a FON has been granted shall inform the relevant system operator immediately in the following circumstances:
the HVDC system is temporarily subject to either a significant modification or loss of capability, due to implementation of one or more modifications of significance to its performance; or
in case of equipment failures leading to non-compliance with some relevant requirements.
The HVDC system owner shall apply to the relevant system operator for a limited operational notification (LON) if the HVDC system owner reasonably expects the circumstances detailed in paragraph 1 to persist for more than three months.
A LON shall be issued by the relevant system operator with a clear identification of:
the unresolved issues justifying the granting of the LON;
the responsibilities and timescales for expected solution; and
a maximum period of validity which shall not exceed 12 months. The initial period granted may be shorter with the possibility for extension if evidence to the satisfaction of the relevant system operator demonstrates that substantial progress has been made towards achieving full compliance.
The FON shall be suspended during the period of validity of the LON with regard to the subjects for which the LON has been issued.
A further prolongation of the period of validity of the LON may be granted upon request for a derogation made to the relevant system operator before the expiry of that period, in accordance with Articles 79 and 80.
The relevant system operator may refuse the operation of the HVDC system if the LON terminates and the circumstance which caused it to be issued remains. In such a case the FON shall automatically be invalid.
If the relevant system operator does not grant an extension of the period of validity of the LON in accordance with paragraph 5 or if it refuses to allow the operation of the HVDC system once the LON is no longer valid in accordance with paragraph 6, the HVDC system owner may refer the issue for decision to the regulatory authority within six months after the notification of the decision of the relevant system operator.