At a glanceThe demand for generation from re-newable energy sources (RES) is grow-ing faster than in previous years, notonly in North America and Europe, butall over the world. Developers arepushing the boundaries of technology,producing larger wind turbines andmore efficient photovoltaic modules,while investors are eyeing a great dealof new RES projects, some in several100 MW magnitude.

The effect of integrating such largeamounts of variable and partially pre-dictable RES makes electrical powersystems more vulnerable and poseschallenges for developers and grid op-erators.

While developers seek reliable RESpower plant design that can guaranteetheir return on investment, grid opera-tors demand very strict technicalguidelines to ensure safe operation.

Siemens Power Technologies Interna-tional (Siemens PTI) combines its re-nowned expertise and extensive expe-rience in power system consulting tooffer:

∂ complete solutions for RES powerplant design and system integration

∂ ensured, reliable and cost efficientperformance of RES power plants

Siemens PTI is the ideal partner duringall phases of development and opera-tion of RES power plants.

The challengeFrom the design all the way to imple-mentation of RES power plants, severaltechnical and economical aspects needto be taken into consideration.

In the design phase, plant componentsneed to be optimally dimensioned sothat performance expectations are ful-filled while investment and operationcosts are kept to a minimum.

Grid operators require RES powerplants to perform according to specifictechnical guidelines included in a gridcode. The performance of an RES pow-er plant at the point of interconnectionis directly related to the technical char-acteristics of the plant’s grid compo-nents. Consequently, a suitable andvalidated model is required to studythe performance of the plant.

Our solutionSiemens PTI offers consulting servicesfor the design of RES power plants, aswell as for integrating these plants intothe power system. Our solution bridg-es the gap between design require-ments for the internal electrical net-work of the RES power plant, and reli-able performance and control of theplant amid full compliance with thegrid code. Our vast experience in gen-eration interconnection studies ena-bles us to ensure optimal integrationof these plants into the grid.

RES power plant designThe following studies are typically of-fered for the design of the internalelectrical network of RES power plantsand an analysis of the behavior ofplants as a whole:

∂ grid design (cables, transformers,compensation)

∂ design of protection systems anddefinition of settings

∂ reliability focused design and availa-bility analysis

∂ estimation of energy losses

∂ wind turbine/photovoltaics model-ing and validation

∂ grid code compliance investigations(reactive power capability, faultride-through)

∂ power quality, including harmonicsanalysis (on-site measurements anddesign of mitigation measures) andvoltage fluctuation investigation

∂ insulation coordination, overvoltageprotection

∂ lightning protection system design

∂ neutral grounding design and di-mensioning

∂ grounding design for personnelsafety

∂ dimensioning of auxiliary systemand equipment

∂ arc flash study

∂ plant-level controller design andmodeling

Moreover, Siemens PTI offers its exper-tise to support solving technical prob-lems during project execution and/orplant operation.

System integration ofrenewable energyPlant design and grid code compliancefor developers and EPCs

siemens.com/power-technologies

Application example:Offshore wind power plantSiemens PTI has performed design andintegration studies for a considerablenumber of RES power plants, especiallylarge offshore wind power projects,worldwide.

An essential requirement for any gridanalysis is a suitable model. For a windpower plant (WPP), a model representsthe technical characteristics of the in-ternal power system of the plant all theway down to the point of interconnec-tion, and includes the individual windturbine models. Siemens PTI’s PSS®

Product Suite offers a wide selection ofstandard turbine models. In addition,Siemens PTI develops customized tur-bine models and validates them for themost accurate and realistic perfor-mance.

Grid code demands that WPPs complywith a set of technical requirements atthe point of interconnection. Specificinvestigations evaluate performance ofthe WPP from several technical per-spectives and help devise optimization.

Dynamic stability studies assess thedynamic behavior of the WPP undersystem disturbances. Included in theseanalyses is the comparison of WPP

Figure 1: Network topology of an offshore WPPmodeled in PSS®SINCAL

performance with fault ride-throughrequirements of grid code.

Harmonics analysis examines harmonicvoltage levels produced by the WPP,combined with background harmonicsat the point of interconnection, againstgrid code requirements and otherstandards (e.g. IEC 61000). Mitigationmeasures, such as design and imple-mentation of harmonic filters, are de-vised in case the requirements are notmet. The overall performance of theWPP with the mitigation measures isthen verified.

Figure 2: Real and reactive power curves dur-ing a fault-ride-through simulation

Figure 3: Harmonic spectrum at the point of

common coupling

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Ubg [%] Uwtg [%] G5/4-1 planning level [%]

Published bySiemens AG 2018

Energy Management DivisionFreyeslebenstrasse 191058 Erlangen, Germany

For more information, please contactpower-technologies.energy@siemens.com

AL=N, ECCN=NSubject to changes and errors. The infor-mation given in this document only con-tains general descriptions and/or perfor-mance features which may not alwaysspecifically reflect those described, orwhich may undergo modification in thecourse of further development of theproducts. The requested performance fea-tures are binding only when they are ex-pressly agreed upon in the concluded con-tract.