Challenge

In August 2024, a critical failure occurred at a power plant in Debrecen, Hungary, when a 25-year-old static frequency converter (SFC) unexpectedly shut down. The SFC, a vital component for starting the site’s 6FA gas turbine, suffered a control system malfunction that rendered the unit inoperable. With no compatible spare parts available and the original equipment manufacturer no longer supporting the system, the plant was forced into an unplanned outage. The urgency was compounded by the fact that the outage occurred during a period of high energy demand, leaving the customer with limited options and growing operational risk.

SEMIPOL™ (SEE/SFC) is based on a modular design and can be applied for many solutions, industries, and applications.

Case

The failed SFC was an outdated third-party unit—an aging system that had reliably served the plant for decades but had reached the end of its supported lifecycle. The failure created a complex scenario: the control cards were no longer communicating with the PLC, and the system could not be restarted. The end customer, Veolia Energia Magyarors­zág Zrt., engaged GE Vernova’s Gas Power business, their long-standing technology partner, to help identify a viable path forward. Multiple suppliers were consulted, but most proposed only partial solutions or recommended a full system replacement. While technically feasible, this approach came with a lead time of at least 12 months, during which the plant would remain offline and unable to contribute to the grid.

Solution

Power Conversion & Storage, a GE Vernova business, was brought in by GE Vernova’s Gas Power business to assess the situation and engineer a recovery strategy. Leveraging its SEMIPOL™ D4.2 controller platform, the team developed a tailored bypass control system that replaced the failed components and re-enabled turbine startup. The solution was designed, manufactured, and delivered in just five weeks - compressing what is typically a multi-month process into a matter of weeks.

This achievement was made possible by three critical enablers:

• Expertise: Power Conversion & Storage’s deep knowledge of SFC systems, including third-party legacy equipment, allowed for rapid diagnostics and a precise retrofit design.
   
• Manufacturing readiness: The regional facility in Berlin maintained emergency stock and had the flexibility to produce non-standard configurations on short notice.
   
• Execution agility: Engineering and project teams were mobilized immediately, reprioritizing resources to meet the customer’s urgent needs without compromising quality or safety.

The temporary SEMIPOL™ D4.2-based solution will remain in operation until the delivery and commissioning of a new, fully integrated SEMIPOL™ SFC system - planned within the next year.

Background

SFCs - also known as soft starters or load commutated inverters (LCIs) - are essential for the controlled acceleration of gas turbines. Without a functioning SFC, the turbine cannot reach operational speed, and the plant cannot generate power. As these systems age, the risk of failure increases, particularly when spare parts become obsolete and technical support is no longer available. The Debrecen case underscores the operational vulnerability of unsupported legacy systems and highlights the importance of lifecycle planning and modernization.

Looking at the future

The customer has already committed to replacing the legacy SFC with Power Conversion & Storage’s SEMIPOL™ system. This next-generation solution will be tailored to the plant’s specific requirements, ensuring long-term reliability, maintainability, and performance. The collaboration between Gas Power and Power Conversion & Storage demonstrates the strength of GE Vernova’s integrated capabilities - delivering both emergency recovery and full modernization solutions. With deep technical expertise, flexible manufacturing, and a customer-first approach, Power Conversion & Storage is prepared to support similar challenges across the
industry, even when dealing with third-party equipment.

Power Conversion & Storage’s ability to deliver a custom SFC control solution in just five weeks demonstrates the value of expertise, manufacturing readiness, and customer-centric execution.

Parramatta Light Rail Sydney, Australia

GE Vernova was responsible for delivering both the Traction Power Substations (TPS) and the stray current monitoring system for the Parramatta Light Rail. 

The Parramatta Light Rail is one of the New South Wales Government’s major infrastructure projects, designed to serve the growing population of Greater Sydney. It spans a corridor that starts from Westmead and extends to Carlingford, passing through the Parramatta central business district and Camellia. The project required highly integrated electrical infrastructure capable of meeting strict technical specifications while also operating seamlessly within a constrained urban environment. 

This light rail line covers a distance of 12 km and operates at high frequency, providing a link between Westmead and Carlingford.

Challenge

The design needed to accommodate demanding performance standards, including protection coordination, environmental resilience, and compliance with external stakeholder requirements. Simultaneously, spatial efficiency was a critical driver, necessitating compact substation layouts and strategic internal component placement to align with site limitations. 

Additional challenges stemmed from strict interface conditions both physical and functional that required attention to equipment arrangement, building access orientation, and communication system integration. Delivering a system that balanced performance, compliance, and constructability in such a confined and highly regulated context was a key aspect of the engineering.

Solutions

GE Vernova successfully delivered seven fully engineered, manufactured, and commissioned Traction Power Substations. Each substation is designed to supply 1.5 MW of 750 V DC power. Substation earth bars within the TPS buildings were engineered to meet the grounding requirements of each installed equipment, ensuring compliance with protection, safety, and operational standards. To continuously supervise and alert to the performance of the rail insulation, a Stray Current Monitoring System was designed and installed. The system measures the rail-to-earth potential along the alignment under operational conditions, complete with central analysis, visualization, signaling and archiving capabilities at the Central Evaluation Unit installed as a virtual machine in the Operation and Control Centre.

Main components

A local SCADA/HMI is provided for the user to control and monitoring the entire traction power substation. 

The system collects information from all different parts of the substation, processes the data and displays it on the local SCADA. In addition, trending and storage of voltage, current and temperature values over extended periods of time.

The selection of local or remote control is via a keyswitch on the front of the panel.

Benefits

• Off-site system integration of the traction power systems equipment in containerized substations allowed for reduced commissioning duration and minimized interface risks.
• Custom engineering - By closely aligning with the client’s specifications, we ensured design compliance, and compatibility with project-specific technologies. This contributed to ease of use and optimised fault finding.
• Local engineering support - Our ability to respond quickly on-site and design in accordance with standards such as TfNSW specifications and AS (Australian Standards), etc. enabled highly tailored system configurations and close technical support throughout the project life cycle.
• High reliability and availability - N-1 redundancy is built into both power systems and cooling infrastructure to ensure no signal point of failure affects system availability. Remote bypass and isolation capabilities enable fast recovery and operational continuity, even in fault conditions.

Looking at the future

GE Vernova's Power Conversion & Storage business has a strong track record in delivering traction power systems for DC light rail projects across Australia, including completed systems in Canberra, Newcastle, and Gold Coast, as well as ongoing design and engineering engagements in Canberra and the mining space. 

As one of the flagship infrastructure initiatives led by the New South Wales (NSW) government, this project further reinforced GE Vernova’s leadership and reputation in Australia’s DC light rail power systems sector.

Building on this foundation, we are prepared to support the next generation of electrified DC rail projects globally with scalable, future-ready power technologies that align with long-term transport vision.

Challenge

The customer required a converter station capable of converting the energy from a public 220 kV 50 Hz grid to a level required for the railway-operated 110 kV 16.7 Hz distribution grid. The key objectives of the project were to achieve the highest conversion efficiency, reliability and system availability at the lowest possible cost.

System overview

The Mannheim station consists of a single independent converter block. It connects to the 220 kV 50 Hz 3-phase grid through an oil-immersed transformer (ONAN cooling system) and feeds the German Railway owned and operated 110 kV 16.7 Hz single phase distribution network via a step up single phase transformer.

Converter system

The power part of the converter block consists of one converter system based on the proven MV 7000 converter type. The converter is rated at 150 MVA and is located in a single building. A single converter includes 3 x 5 medium voltage inverter units, each with the following main components:

• An input 3-phase pulse controlled sub-inverter
• A DC link with a 33.4 Hz filter
• An output 1-phase 4QS sub-inverter 

The core components in each sub-inverter are the press-pack IGBT modules organised in two phase-segments and fitted with a patented pull-out mechanism including the IGBT control amplifiers.

Providing the interface to the distribution grid

Cooling system

The converter block has its own dedicated cooling system with a mix of glycol and water. The power electronics as well as other components of the inverter units are directly cooled with this fluid. The advantage here is compact design and small space requirements. The heat is then dissipated in a water-air heat exchanger. Two water pumps are installed (100% redundancy) to provide continuous circulation. All systems are monitored and the pumps are switched over every 24 hours. To reduce the space required, the heat exchangers are located on the roof of each converter block.

Additional air-conditioning is provided for the house premises.

Control system

Internal converter control enables the following operation modes:

• Standard control in all 4 quadrants (according to the P/f, Q/U characteristic)
• Phase shift operation (supply of reactive power to the railway grid only)
• Parallel operation with rotary frequency converter
• Black Start-Up of rail grid

The control system allows for either local or remote operation via a user-friendly HDM interface.

Our SFC technology brings multiple advantages to the operator

Static frequency converter for railway application

Challenge

To increase speed and capacity on a segment of ca. 50 km along the European Corridor CE30 from Knappenrohde, Germany to the system interface at the polish border, Deutsche Bahn extends and electrifies an existing rail line. As part of this project, a static converter station to feed the 16.7 Hz 15 kV overhead catenaries was contracted as a turn-key project in Lohsa, Germany to a consortium lead by Power Conversion & Storage. The key objectives of the project were to achieve the highest conversion efficiency, reliability and system availability at the lowest possible cost.

System overview

The Lohsa station consists of three independent blocks operating fully redundantly. It connects to the 110 kV 3-phase grid through an oil- immersed transformer (ONAN cooling system) and feeds the 15 kV 16.7 Hz overhead catenary system directly as well as through a system of auto transformers. For maximum efficiency, each block employs air-core reactors on the 15 kV rail electrification side (transformer-less design). Connection of a 50 Hz filter is not necessary thanks to the innovative converter concept and control algorithm. On the 15 kV rail side, only a small passive filter is required to meet the strict harmonics requirements of DB.

Converter system

Each block employs three converters based on the proven MV 7000 type, with the main components being:

• An input 3-phase pulse controlled sub-inverter
• A DC link with an integrated 33.4 Hz filter and a fast discharge/ earthing device
• An output 1-phase 4QS sub-inverter 

Each sub-inverter contains press-pack IGBT modules organised in phase-segments and fitted with a patented pull-out mechanism including the IGBT control amplifiers.

Providing the interface to the distribution grid

Cooling system

Each converter block has its own dedicated closed-circuit cooling system with a mix of glycol and water. The power electronics is directly cooled with this fluid, to achieve compact design and small space requirements. The heat is then dissipated in a water-air heat exchanger. Two SFC-controlled water pumps are installed (100% redundancy) to provide continuous circulation. All systems are automatically monitored and the pumps are regularly switched over. Additional secondary air-cooling is provided for the E-house in each block.

Control system

Internal converter control enables the following operation modes:

• Standard control in all 4 quadrants (according to the P/f, Q/U characteristic)
• Reactive Compensation/ STATCOM (supply of reactive power to the railway grid only)
• Parallel operation with other generation units integrated on the 15 kV line
• Isolated mode (creating independent rail grid), with automatic synchronization to three-phase grid before reconnection
• Remote control by sinusoidal reference signal (Pilot Mode) or Autonomous Mode based on asynchronous
  telemetry reference signal can be provided as well.
• Black Start-Up of rail grid

Remote short circuits are handled reliably by the control algorithms. The control system allows for either local or remote operation via a user-friendly HDM interface and integration to SCADA according to IEC 61850 (IEC 60870-105-4 can be provided as well).

Our SFC tecnology brings multiple advantages to the operator

Static frequency converter for railway application

Challenge

To increase availability and reduce maintenance efforts while maintaining the traction power supply service level at the lowest possible cost, DB wished to replace its existing rotating equipment in Bützow and Schwerin (Germany). For both locations, two static converter stations of 2x15 MW each to feed the 16.7 Hz 15 kV overhead catenaries were contracted as a turn-key project to a consortium with Power Conversion & Storage as the key participant. The systems are currently in commissioning phase.

System overview

Each station consists of two independent blocks operating fully redundantly. They connect to the 110 kV 3-phase grid through an oil-immersed transformer (ONAN cooling system) and feed the 15kV 16.7Hz overhead catenary system directly. For maximum efficiency, each block employs air-core reactors on the 15 kV rail electrification side (transformer-less design). Connection of a 50 Hz filter is not necessary thanks to the innovative converter concept and control algorithm. On the 15 kV rail side, only a small passive filter is required to meet the strict harmonics requirements of DB.

Providing the interface to the distribution grid

Cooling system

Each converter block has its own dedicated closed-loop cooling system with a mix of glycol and water The power electronics is directly cooled with this fluid, to achieve compact design and small space requirements. The heat is then dissipated in a water-air heat exchanger. A high-availability canned motor pump is installed to provide continuous circulation. All systems are monitored automatically. Additional secondary air-cooling is provided for the E-house in each block.

Control system

Internal converter control enables the following operation modes:

• Standard control in all 4 quadrants (according to the P/f, Q/U characteristic)
• Reactive Compensation/ STATCOM (supply of reactive power to the railway grid only)
• Parallel operation with other generation units integrated on the 15kV line
• Isolated mode (creating independent rail grid), with automatic synchronization to three-phase grid before reconnection
• Remote control by sinusoidal reference signal (Pilot Mode) or Autonomous Mode based on asynchronous telemetry reference signal can be provided as well.
• Black Start-Up of rail grid

Remote short circuits are handled reliably by the control algorithms. The control system allows for either local or remote operation via a user-friendly HDM interface and integration to SCADA according to IEC 61850 (IEC60870-105-4 can be provided as well).

Our SFC technology brings multiple advantages to the operator 

Static frequency converter for railway application