Stabilize AC grids in milliseconds and get the most out of existing infrastructure

UPFC PLUS

Increasingly decentralized energy systems and the associated uncontrolled power flows pose new challenges for the existing, mature grid infrastructure. Thermal overloads in the lines and a growing number of cases in which frequency and voltage come critically close to acceptable range limits, or even exceed them, threaten grid stability and the transmission infrastructure, and often require costly redispatch intervention to deal with current and voltage factors. Compared to traditional power flow controllers, UPFC PLUS controls power flow in just milliseconds. The Unified Power Flow Controller UPFC PLUS thus stabilizes the AC grid even when critical situations develop suddenly (Grid Code N-1). That means UPFC PLUS lets you get the most from your existing grid capacity while maintaining maximum protection, reducing the risk of power failures, and minimizing redispatch costs.

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After our UPFC PLUS Launch at the 22nd of September, 2020. We received some questions. Please have a look and find our answers below.
Siemens UPFC PLUS at a glance

Overview of technical benefits

Protection when line outages occur (N-1)

Even when sudden faults occur, UPFC PLUS stabilizes the AC grid, offering highly efficient support for Grid Code N-1 situations affecting the existing grid infrastructure. Its Modular Multilevel Converter (MMC) technology enables a sufficiently rapid response time of just a few milliseconds in order to prevent power failures.

Benefits

Scope of application of UPFC PLUS

The UPFC PLUS solution is based on the Modular Multilevel Converter (MMC) architecture from voltage source converters (VSC) in semiconductor technology, as developed by Siemens and already proven in SVC PLUS and HVDC PLUS.

 

A Unified Power Flow Controller (UPFC) is used to control and influence the electrical energy transmitted through individual lines in intermeshed, supra-regional power networks. UPFC can therefore be used to meet specific, contractually agreed power throughputs in intermeshed grids.

 

The scope of application is aimed at high-voltage electricity transmission networks using three-phase AC at voltage ranges of 220 kV to 500kV, and its control functions make use of power electronics similar to the systems used in HVDC transmission. Unlike HVDC, the power electronics are not used directly for power transmission but to influence and modulate the AC current being transmitted. In power electronics, UPFC is an example of a flexible AC transmission system (FACTS).

Like a traffic guidance system

Like smart traffic guidance systems, UPFC PLUS controls the power flow via available line capacity in the AC grid.

Reducing throughput costs

Short-term, high-volume infeed of renewables often leads to costs for energy throughput via third-party grids. UPFC PLUS directs the electricity through your own high-voltage grid.

Avoiding line overload

Unexpectedly high infeed levels from PV systems and wind turbines can cause overloads on individual lines. UPFC directs the electricity effectively using available line capacity.

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UPFC PLUS Whitepaper

Questions and answers

If you have any questions, which are not adressed below, please contact us

Generic PSSE models are available to study benefits of UPFC PLUS in the transmission grid.

Generic PSSE models are available to study benefits of UPFC PLUS in the transmission grid.

Main use of UPFC PLUS is dynamic load flow management. Siemens also offers Grid forming converter to support inertia. 

Main use of UPFC PLUS is dynamic load flow management. Siemens also offers Grid forming converter to support inertia. 

UPFC PLUS is new application based on existing well proven hardware which is generally used in SVC PLUS and HVDC PLUS.

Many discussions are in pre-acquisition phase and currently we are looking for a pilot project.

UPFC PLUS is targeting dynamic load flow management for TSO and DSO. We are looking for a pilot project.

Presently, Siemens offers UPFC PLUS. Only SSSC is the outlook.

Presently, Siemens offers UPFC PLUS. Only SSSC is the outlook.

UPFC PLUS has two VSC converters. One is connected in series and another is connected in stunt. Siemens recommends UPFC PLUS for dynamic load flow management.

Siemens offers UPFC PLUS. UPFC PLUS  has two VSC converters. One is connected in series and another is connected in stunt Both converters are coupled via transformer to the transmission line.

UPFC PLUS is modular solution. It can be customized to customer requirements. Technically it is possible to replace this mentioned configuration and details should be discussed further. 

Optimal use of existing assets is possible via dynamic load flow management. It offers new ways to control load flow in transmission lines. 

Operation in overload condition is necessary to manage load flow during and post n-1 contingency. Overload capability is built in.

Yes, it is possible. The shunt converter operates as a STATCOM and can include all known control features.

UPFC PLUS is new application based on existing well proven hardware which is generally used in SVC PLUS and HVDC PLUS.

Please submit your contact details. We will contact you as soon as possible to provide reliable information on prices.

UPFC PLUS offers same reliability as HVDC because of same hardware. There is practically no difference except the physical size of the converter. 

UPFC PLUS is the brand name of Siemens Energy and is a UPFC.

Please submit your contact details. We will contact you as soon as possible to provide reliable information on costs.

Siemens offers UPFC PLUS for dynamic load flow management for TSOs and DSOs where high ratings are necessary. 

Please submit your contact details. We will contact you as soon as possible to provide reliable information on system models.

Yes, it can be integrated together with existing reactive power sources.

Yes, active power can be transmitted via the dc bus. 

Siemens offers SVC PLUS FS where VSC converter are backed up with energy storage. Currently it is not foreseen to include batteries directly to the dc bus of UPFC PLUS. May be an alternative in future. 

Siemens offers SVC PLUS FS where VSC converter are backed up with energy storage. Currently it is not foreseen to include storage directly to the dc bus of UPFC PLUS. May be an alternative in future.