Grid stabilization to power a greener future: Siemens Energy launches UPFC PLUS

September 22, 2020

  • Dynamic load flow control solution for grid stabilization and resilience
  • UPFC PLUS controls load flow in milliseconds
  • Facilitating the increasing integration of renewable energy


With its new Unified Power Flow Controller, called UPFC PLUS, Siemens Energy is expanding the options for grid stabilization. The UPFC PLUS will help system operators stabilize the grid by dynamically controlling the load flow in alternating-current grids. Easy to integrate into existing infrastructure, the UPFC PLUS improves the efficiency of today’s power grid while providing the grid stability and resilience required in the ever-changing energy landscape. 

Overcoming today’s grid challenges

Power systems that are increasingly driven by fluctuating renewable energy sources can be kept stable using different measures. However, the options for expanding the network often entail major modifications to the existing infrastructure, therefore representing a big financial burden for transmission system operators. Compared with other grid stabilization technologies, the UPFC PLUS can be easily integrated into existing infrastructure and represents a cost-efficient solution for increased efficiency in the grid.

The optimal solution: Dynamic load flow control

The UPFC PLUS can balance load flow in the alternating-current grid within milliseconds, outperforming other flow management components. The UPFC PLUS is arranged as two voltage sources: one in parallel that controls voltage and one in series connected to the AC line. This means that it provides reactive power compensation, voltage control, and active power load flow control in one space-saving unit and ensures that the system can always tolerate an unexpected failure or outage of a single system component.

“Our new UPFC PLUS technology broadens grid operators’ capabilities to quickly respond to fluctuating power demand in order to support the integration of renewable energy, and ensures grid resilience and stability,” says Hauke Jürgensen, head of Large Transmission Solutions at Siemens Energy. “The UPFC PLUS is a cost-efficient grid stabilization solution that will help grid operators master today’s and tomorrow’s challenges in a rapidly evolving energy landscape.”

The technical structure of the UPFC PLUS

The UPFC PLUS comprises five main components:

  1. A back-to-back converter arrangement as a symmetrical monopole to achieve the required voltage level 
  2. Siemens Energy’s well-known power modules that form the modular multilevel voltage-sourced converter (VSC)
  3. A series transformer that injects the voltage into the transmission line to either reduce or increase the current flow through the system 
  4. The shunt transformer that controls the voltage and the infeed of reactive power
  5. A fast-bypass unit that protects the series side and ensures fast post-fault recovery

The solution is geared to the high-voltage level of electrical interconnected networks operated with three-phase alternating current and covers all voltage levels worldwide.



Media Relations

Siemens Energy 

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Siemens Gas and Power GmbH & Co. KG is the global energy business of the Siemens group, which has been working with its customers on solutions for the evolving demands of industry and society for more than 150 years. With planned stock listing, Siemens’ energy business will operate independently as Siemens Energy in the future.

It will offer broad expertise across the entire energy value chain, along with a comprehensive portfolio for utilities, independent power producers, transmission system operators, the oil and gas industry, and other energy-intensive industries. With its products, solutions, systems, and services, Siemens Energy will address the extraction, processing, and transport of oil and gas as well as power and heat generation in central and distributed thermal power plants, and power transmission and technologies for the energy transformation, including storage and sector-coupling solutions. The majority stake in Siemens Gamesa Renewable Energy will round out its future-oriented portfolio. With its commitment to leading the way in decarbonization of the global energy system, Siemens Energy will be a partner of choice for companies, governments, and customers on their path to a more sustainable future. With around 90,000 employees worldwide, Siemens Energy will help shape the energy systems of today and tomorrow.