Enemalta this morning categorically denied reports in The Times which claimed that the widespread power cut on 13 August was caused by “faulty settings” in the Malta-Italy Interconnector. Earlier this week it published the inquiry report, which found that the power outage was caused by a lightning storm in Sicily.
The newspaper, citing "senior Enemalta sources," said the interconnector, which at the time of the fault was carrying about 190MW of electricity, tripped due to faulty settings at the Magħtab terminal station.
“Enemalta regrets the baseless allegations made in an attempt to tarnish the reputation of the Maltese engineers who have been supporting the Company for years, and who have worked hard to complete the Malta-Italy Interconnector, and to diligently restore electricity supply as soon as possible following last week’s disturbance, whilst at the same time ensuring that the national distribution network and all related infrastructure were not compromised,” the company said in a statement.
“The Company would like to make the following clarifications:
1. As confirmed by Enemalta plc and Terna Rete Italia on Tuesday 11th August, the “problem” that caused the electricity supply disruption on Thursday 6th August was in fact caused by a disturbance in the electricity network in Sicily, when lightning hit parts of the network infrastructure.
2. The lightning strike caused an earth current (overcurrent in the electricity network) which was registered in the relay logs at the Enemalta Substation at Ragusa and also at the Maghtab Terminal Station within 6 milliseconds of each other, practically instantaneously.
3. The earth current continued for more than 1,400 milliseconds (1.4 seconds), which, by international industry standards, is considered to be an extremely high duration.
4. Had this earth current been allowed to persist, Enemalta would have risked damaging, or exerting undue pressure, to its Interconnector infrastructure, which, in turn, could have made it unavailable for a much longer time (until repairs or replacements are completed), or potentially even breakdown at a later stage.
5. At 1,400 milliseconds, the automatic system protection relays triggered the circuit breakers at the Maghtab Terminal Station to disconnect supply and protect the Interconnector transformers and related infrastructure from the earth current, cutting off power flow from Sicily to Malta.
6. The system protection operated perfectly to achieve its main objective – safeguarding the crucial Interconnector equipment from the risk of permanent damage or undue pressure.
7. The media allegation that the settings were faulty is completely false. The settings were perfectly in line with the specifications of the original project design, which had been reviewed by all stakeholders and related international consultants of the Interconnector project.
8. The media allegation that the “settings were too low for the high voltage carried” are not only untrue, but also technically incorrect, since voltage has nothing to do with issues related to earth current disturbances.
9. Had the protection settings been “faulty”, Enemalta would have risked damage to its infrastructure. However, since the protection systems operated perfectly, Enemalta was able to re-synchronise the Maltese and Italian networks in a very short time, as soon as it received a confirmation from its Italian counterparts that the earth current disturbance in the Sicilian network had been cleared.
10. The fact that no electricity supply disruptions were recorded in Sicily has no bearing on the consequences of the earth current disturbance on the Maltese network, since the two electricity systems have different specifications and levels of redundancy based on their respective capacities.
Enemalta plc and Terna Rete Italia are working together to analyse all current systems involved to confirm if any additional measures can be taken to minimise the effects of such inevitable situations.