Sogelma and Thytronic: Protection engineering study and commissioning for the Marghera Commercial Port


POSITIONS: Europe - Italy


Sogelma and Thytronic: Engineering Study and Commissioning for the Marghera Commercial Port

Sogelma was founded in Scandicci (Florence) in 1977. Specialized in the implementation of large-scale projects in both public and private sectors, Sogelma boasts significant experience in airport, port, and road/highway infrastructure. 
In 2014, Sogelma won the tender for the refurbishment of electrical cabins at the Marghera commercial port. 
"When we won the tender in 2014 for the refurbishment of cabins at the Marghera commercial port, we decided to continue using Thytronic protection systems, which were already present in the facility," says Daniele Albini, Sogelma's technical manager. 
The system, consisting of 5 electric cabins connected in a loop, experienced frequent malfunctions, often coinciding with external faults, leading to undesired activations of the protections within the port's electrical system. 
"The continuous external faults and the untimely tripping of some user electrical network protections caused significant disruptions for the port, with a strong impact on operations and substantial economic damages," explains Albini. 
"In 2019, following the acquisition of a new contract for the refurbishment of a new cabin, we decided to completely rethink the logical selectivity of the system, entrusting Thytronic with the engineering study of the protection system for the entire distribution medium voltage (MT) electrical network of the port." 
The THYTRONIC engineering study specifically covered:
  • CALCULATION OF SHORT-CIRCUIT CURRENTS to determine the currents and voltages involved during different types of faults,
  • VERIFICATION OF CHARACTERISTICS OF CTs (CURRENT TRANSFORMERS) AND VTs (VOLTAGE TRANSFORMERS) FOR PROTECTION to ensure that the characteristics of the measurement transformers were suitable for the correct operation of the protection system,
  • COORDINATION PROTECTION STUDY to redefine the settings of THYTRONIC relays and the logical selectivity messages on the redundant fiber optic TCP/IP communication network, with the aim of meeting protection requirements for internal faults, service continuity, and selectivity.
The THYTRONIC short-circuit study initially highlighted plant-related issues, particularly regarding the short-circuit withstand of some cable lines and, above all, the currents and voltages involved by the primary distribution autotransformers of the port during external ground faults. 
"We deemed it necessary to replace the autotransformers, respectively with appropriately sized lines and transformers, to prevent ground faults on the distribution network from causing capacitive currents and overvoltages on the user network. With the new transformers, a grounded connection with resistance was also introduced, resulting in a reduction of transient overvoltages and increased reliability in detecting internal faults towards the ground by the protections," Albini recounts. 
The coordination study also led to the adjustment of protection relay settings and a redefinition of interlocking logics for effective logical selectivity in different user network configurations. 
After the aforementioned plant modifications, the completion of the study, and a thorough commissioning phase conducted by THYTRONIC technicians for the calibration and functional testing of the protection relays, the system is currently in operation without any recorded interruptions due to untimely protection interventions. 
"In the event of an internal fault, we have also confirmed the selective operation of the protection system, limiting the service disruption to the bare minimum and reducing the time for fault localization and repair," confirms Sogelma's technical director.
"The competence of the technicians, along with the support and after-sales assistance received, was a fundamental element for the success of the project; we continue to rely on Thytronic for other projects as well, given their availability to support our technical support requests. Customer trust is also earned through professionalism and the quality of services offered, an aspect that Thytronic has always excelled in," concludes Albini.

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