Steel plant - Sremska Mitrovica, Serbia

Metalfer Steel Mill (MSM) is a Serbian steel plant, located in the Northwest of the country, close to the Croatian border. It is owning and operating an EAF-based steel mill manufacturing construction steel products from recycled scrap metal. They are the only rebar producer in Serbia and the leading supplier on the local market, also exporting to the neighboring countries.

MSM is part of Metalfer Group, an industrial group of companies involved in mining, metallurgy, energy, and trading, established in Serbia in 2002.

In November 2021, GE Power Conversion was awarded a contract to provide MSM with a STATCOM system to help stabilize the local grid.

Challenge

Our customer is operating a mini mill based on an Electric Arc Furnace (EAF) melt shop with a capacity of 400 kT/Y. The EAF is generating high voltage flicker, that the existing SVC system cannot compensate enough, preventing the facility from reaching the standard limit.

The flicker is causing significant power quality issues, to the plant itself but also to the neighborhood. As the Croatian authorities were complaining, MSM has been ordered by the local Transmission System Operator (TSO) to resolve the problem or to shut down the power.

Solution

To answer this need for high compensation level, GE Power Conversion proposed a STATCOM system based on its Modular Multilevel Converter (MMC) technology. This advanced transformer less solution, using the MM7 drive, offers high performance with a flicker mitigation ratio up to 6.0 –a strong asset over competition that allowed GE to be selected for this project.

Scope of supply

• MM7 STATCOM 20 kV/from -49MVar to +121 MVAr
• 3 phases, each constituted by 5 towers
• Engineering, delivery, supervision of erection and commissioning

The equipment has been delivered at the end of 2022 and started operating in March 2023. It was then successfully tested in April 2023.

Looking at the future

In a near future, MSM intends to change the plant’s bus voltage from 20 kV to 33 kV – a grid expansion that GE Power Conversion already anticipated and will therefore easily be implemented by adding 2 towers per phase to the MM7, thanks to the high flexibility of the solution.

Benefits

Despite a relatively low grid quality factor (X/R) and short-circuit level, Power Conversion's solution achieved a flicker reduction above 5, hence meeting the customer's expectations. 

About the project

In 2018, GE Electrification was awarded a contract by Elecnor Spain to supply the Static Synchronous Compensator (STATCOM) solution for the Electrical Balance of Plant (EBoP) of a wind farm developed in Jordan by Mass Energy Group Holding, a subsidiary of Mass Global.

This 100 MW wind facility, located in Al-Tafila Governorate, about 130 km south of the capital Amman, entered successfully into operation at the beginning of 2020.

It is the first renewable energy project by Mass Energy Group Holding.

This development fell within the Jordan 2025 Vision and Strategy, a plan which aims at increasing the share of renewable energy in the total energy mix to 11% and boost domestic energy production. The Mass Energy wind farm has been developed to power around 150,000 homes and reduce carbon emissions by 233,800 metric tons annually.

The Grid Stability Challenge

Maintaining grid stability and voltage control is necessary especially in today’s world where the evolving power generation scene has become even more challenging for Transmission System Operators – a larger share of renewables, retirement of base-load plants, increased environmental regulation and greater cross-border trading are all making grid stability more complex.

To maintain reliability and quality of power supply in this environment, economical and efficient solutions are needed to provide dynamic voltage support and fast reactive power compensation. By selecting GE Electrification’s STATCOM systems to equip the EBoP, Mass Energy and Elecnor made the choice of a proven technology.

Our Solution

The STATCOMs are power electronics-based power quality devices which ensure dynamic voltage control and increased power transfer capability. They are based on our proven range of Voltage Source Inverters with demonstrated proficiency in energy and industrial applications.

A STATCOM offers a strong dynamic performance, especially a fast response time as well as the ability to generate or absorb reactive power during Fault Ride Through. It therefore helps increase reliability and availability of grid operation. For the Mass wind farm in Tafila, GE Electrification’s scope of work included the development, supply, supervision of erection & commissioning of two 19 MVAr STATCOM systems based on GE’s MV7000 inverter technology.

This solution allows an overload capacity of 300% during 500 milliseconds during the Low Voltage Ride Through.

It enables to solve the quality issues on the grid during operations and can then help improve grid reliability and avoid significant upgrade costs for grid connections.

STATCOM Key Features

• Valve based on IGBT press-pack technology
• Heavy duty solution to allow installation in very harsh remote areas
• Current range up to 300%/500 ms
• Very high availability with N-1 redundancy
• Stepless adjustable cos phi
• Transformer to connect to high voltage grid
• Water cooled through Air/Water exchanger
• Air-conditioned
• Controls based on industry standard components
• Containerized solution to allow very fast installation
• Reduced footprint