An investigation to determine the underlying cause of the "switching fault" which led to yesterday's power outage across the Maltese island has been initiated by Enemalta, the corporation said in a statement.

It said the investigation will be making recommendations for Enemalta to take the necessary steps for the problem not to reoccur. The investigation was requested by Finance Minister Tonio Fenech.

The corporation said the trip at the Delimara power station occurred at 7.35 p.m.

At that time Delimara was producing 155MW whilst Marsa Power Station was supplying 57MW. Turbine no 2 at Power Station Delimara was put in service to meet this demand. During this switching operation, the turbine failed to synchronise in time and this led to the plant in Delimara being overloaded.

This resulted in a rapid drop in frequency throughout the network.

As this was happening the engineers at the Delimara station attempted to manually synchronise the turbine but were not able to complete the operation in time as the evening peak load approached.

This overloaded the system and the protection devices in Delimara operated immediately, shutting down the plant.

At that time, the Marsa station tried unsuccessfully to stabilise the situation but because the load previously carried by Delimara was far too big to cope with, the protection systems in Marsa were also activated, resulting in the total shutdown of the system.

The reserve turbines were immediately started to commence the restoration of supply throughout Malta. Full restoration was achieved by 11.52 p.m.

Enemalta apologised for the inconvenience caused due to this fault, especially during the Good Friday events.