Power transmission operator IPTO SA built the 400/150kV Megalopolis Substation in Greece and modernized some of its older substations. Using the zenon software platform from COPA-DATA for substation automation, implementation partner PROTASIS realized the project ahead of schedule.
Contrary to what the name might suggest, Megalopolis is a small town. With less than 10,000 inhabitants, it derives its significance from criteria other than size. It is the site of a power plant fired with locally mined lignite coal. Extended by two 400-MW combined cycle gas turbine (CCGT) blocks, it remains a vital source of electricity for southern Greece. Located in the center of the Peloponnese peninsula, Megalopolis is also an important junction in the country’s power grid.
Closing electricity transmission gaps
The Greek electricity transmission system is operated, maintained and developed by the Independent Power Transmission Operator (IPTO) SA. It consists of more than 11,000 kilometers of high and extra high voltage (EHV) transmission lines and more than 300 substations. It features submarine connections to the Greek islands as well as links to five neighboring countries.
The system’s backbone, three double-circuit 400 kV lines, transmits electricity mainly from Western Macedonia where 70% of the country's generation capacity is located to the major electricity demand centers of Central and Southern Greece. As part of a long-term plan to improve the reliability of electricity supply throughout Greece, the 400 kV network is extended to Peloponnese. The two lines crossing the Corinth canal and the gulf of Patras meet at Megalopolis. This made it necessary for IPTO to build a new 400 kV / 150 kV substation there.
A critical node of the transmission system
A critical node of the Greek transmission system, the newly erected Megalopolis 400 kV substation features 36 bays with 400 kV, 150 kV and 30 kV equipment, making it a very large and complex installation.
“Our aim was to get a substation meeting the highest standards that we can operate with a high degree of both automation and flexibility”, says Athanasios Georgopoulos, director of the new transmission projects department at IPTO S.A. “As electricity demand was rising, the project was of strategic importance for IPTO and we needed it to be commissioned and energized as soon as possible.”
IPTO is a member of ENTSO-E (European Network of Transmission System Operators for Electricity). When it comes to building transmission projects and substations, the company has ample skills and experience required for the engineering and construction of the required structures and primary equipment. For the implementation of a digital automation system (SAS), though, IPTO decided to call in a contractor and consultant with the appropriate qualifications and experience.
A state of the art digital EHV substation in Greece
IPTO issued a public tender for a powerful, reliable, fail-safe and ergonomic as well as feasible SAS solution. The contract was awarded to PROTASIS, an engineering and consulting company providing services and solutions for transmission and distribution utilities, power generation companies and industrial facilities. PROTASIS is considered one of the leading companies in power systems analysis, studies and consulting and a qualified solutions provider of electrical protection, control, automation and metering systems.
PROTASIS is a Silver member of the global COPA-DATA Partner Community (CDPC), a global network of specialists in the fields of industry and energy automation with an already successful installation record of more than 25 HV Substation Automation Systems. In search of a both cost-effective and stable solution, the Athens-based company used intelligent electronic devices (IEDs) for power grids from Schweitzer Engineering Laboratories (SEL). The specialists created the substation automation system (SAS) using zenon, a software platform from COPA-DATA for manufacturing and the energy industry used to control, monitor and optimize equipment.
zenon is frequently used to control substations. Projects using zenon are highly scalable. The software can be implemented as an on-site control system, as process visualization in the control room or as a gateway to higher-level control systems. One of the software platform’s particular strength is its open and reliable communication with the installed equipment through open interfaces and over 300 native drivers and communication protocols. Another is the principle of setting parameters instead of programming to create comprehensive projects with complex functions. The software platform also provides seamless redundancy in several different ways, making it easy to guarantee an uninterrupted electricity supply.
Efficient, reliable SAS ahead of schedule
Using the “seamless redundancy” functionality within zenon, PROTASIS provided IPTO with a reliable SAS based on two powerful servers operating with hot standby redundancy. It guarantees zero data loss even in the short time period between the breakdown of one processor and the take-over by the backup.
The solution features two separate remote terminal units (RTUs) for the 150 kV side and the 400 kV side. They provide all communication of the substation with the Remote Control Center (RCC) of the Hellenic Transmission System. While the IEC61850 suite of protocols is used for communication with the substation IEDs, communication with the RCC uses the HNZ protocol, a proprietary CEGELEC protocol. This topology ensures the reliability of the communications with RCC without the need of extra interface panels.
The MEGALOPOLIS EHV substation is not only the first zenon-installation in an EHV substation in Greece, it is also the first 400 kV SAS PROTASIS implemented using zenon for automation and visualization in combination with IEDs from SEL. “The size and complexity of the project made us explore and discover powerful functions of zenon of which we were unaware before this project”, says George Arvanitis, project manager, PROTASIS. “With zenon, we delivered an ergonomic, powerful and reliable substation automation and visualization system in the form of an extremely cost-effective, complete solution that is both easy to use and reliable.”
“Due to the seamless redundancy of the system, our SAS operators rest assured they are working on a system that will not fail in critical moments”, Georgopoulos confirms. “The superior ergonomics of the zenon runtime environment provides them with all the required information accurately and in an easily readable form.”
“zenon’s IEC 61850 driver configurator and wizards as well as its bay replication capabilities allowed us to provide the SAS in a very short time”, adds Arvanitis. “Thanks to the software platform’s flexible engineering environment, we created an application that is both intuitive and robust ahead of contractual deadlines.”
IPTO and the Greek electricity consumers benefited from MEGALOPOLIS EHV substation’s early start of operation. Following this project, PROTASIS also signed a contract for the retrofit of the existing 150 kV “MEGALOPOLIS I” substation with new protection and control IEDs. Is the first substation in Greece featuring IEC 62439-3 PRP network topology, and of course its SAS is now also based on the versatile zenon software platform.
- First 400 kV SAS in Greece using zenon for automation and visualization
- Integration of digital hardware
- IEC61850 communication with IEDs
- Communication with the Grid using a proprietary protocol
- Hot standby redundancy guarantees zero data loss
- Cost-effective, complete solution that is both easy to use and reliable