Abstracts - VGB PowerTech Journal 10/2012

Consideration of aspects of grid stability when planning offshore wind farms

Holger Wrede

In conventional transmission and distribution grids the frequency power characteristic of grid-connected generators is utilised for controlling the power balance between actual generation and demand. This physical principle is not given by offshore wind parks which are connected via a high-voltage direct current link to the onshore grid and also uses wind turbines with full-scale frequency converters. Additional requirements to frequency converters have to be defined in grids with a higher amount of converters. Here the special characteristic of offshore grids due to exclusive cabling and the therefore resulting low parallel resonance of the grid impedance have to be attended. All these points influence the stability of the grid and have to be considered in the planning of offshore wind parks.

Definition and verification of the control loop performance for different power plant types

Nataliya Knierim-Dietz, Lutz Hanel and Joachim Lehner

A high control loop performance is important for the operational safety of power plants and enhances the compliance with the increasing requirements from the electrical grid. An indicator-based methodology for the systematic evaluation of the control loop performance is described. This methodology was developed within the framework of the VGB Research Project “Definition and verification of the control loop performance for different power plant types”. The development of the methodology was supported by power plant operators.

Plant concept Andasol 3 - Requirements for electrical and control systems

Frank Dinter and Manfred Steinbach

With the development of modern power plant technology, the solar-thermal power plant An­dasol 3 was commissioned in autumn 2011. Andasol 3 is similar to the adjacent Andasol 1&2 plant a parabolic trough power plant with an installed capacity of 50 MWe and a thermal storage tank with a capacity of 7.5 hours. Concept and technology, specially focusing on control and instrumentation, are presented. Because of the specialised functional units of the solar power plant, I&C consists of several individual control technologies that are grouped in a main control system.

Management of functional safety - SIL in Operation

Günter Dirding

Based on the requirements of the harmonised European Standards, the process “Safety Functional Management” is defined. With these the requirements are established for the entire life-cycle of electrical, electronically and programmable electronically equipment (E/E/PES) within safety equipment. This means that the entire electrical equipment like sensors (field equipment, measurements, etc.), I&C system (hard- and software), and actuators (valves, dampers, etc.) including safety valves have to be considered for the entire life-cycle of all safety systems of the power plant beginning from the first planning up to decommissioning.

Process quality optimisation: Schemes, success factors, experience

Alexander Voskrebenzev and Jürgen Brandt

In light of the climate protection targets, rising energy prices and increasingly tougher competition, the systematic optimisation of process efficiency in fossil-fired power plants provides significant value leverage. Apart from plant-related retrofit measures, systematic monitoring and analysis of efficiency-relevant and often plant-individual key process indicators can lead to further improvement of the plant utilisation ratios. A variety of online software solutions, most of which are independent of process I&C systems, are on offer for this purpose. Within the scope of a project, requirements for RWE Power’s lignite-, hard coal-, and gas-fired power plants regarding the design of PQM systems, their connection to the process I&C systems, and process parameters to be monitored were defined and appropriate utilisation and servicing schemes including organisational structure for the sustainable optimisation of efficiency in the power plants were developed. The SR::EPOS software of the company STEAG Energy Services GmbH was selected as system solution for testing in the pilot units.

IT security analysis of the scada-system in the Nossener Brücke power plant GT-HKW

Martin Mallon and Philippe A.R. Schaeffer

Drewag Stadtwerke Dresden GmbH operates the Nossener Brücke gas turbine combined cycle power plant. The I&C systems were subjected to an IT safety check in order to guarantee the high availability. Measures increasing security were derived. These were implemented after having assessed the risks and feasibility. A PDCA cycle is integrated to guarantee and improve long-term IT security.

Creating a database system for VGB-Standard guidelines of the VGB Plant Identification and Documentation Working Group of VGB’s Power Plant Operations Committee

Harry Königstein, Jörg Kaiser and Michael Schuhmacher

New and/or revised VGB Standards by the VGB Working Panel “Plant Designation and Documentation” are to become more user-friendly. A data-base-supported IT solution is to meet the basic requirements. A data base project has being developed since 2011. A catalogue of requirements - which is going to be the basis for further project realisation - is being developed.

Optimising the firing system of a lignite-fired steam generator

Daniel Sommer, Piotr Olkowski, Dieter Rüsenberg and Heinz-Jürgen Wüllenweber

The Niederaussem power station, besides the 1,000-MW unit “BoA1”, has two 600-MW units and four 300-MW units generating electricity from Rhenish lignite. In view of the changes on the electricity market and the associated future demands on the units, the steam generators, too, have to meet these new conditions. In addition, the firing systems must be adapted to cope with future coal qualities. For these reasons, extensive work was undertaken on the entire plant during the inspection of unit G in 2011. This paper reports on the structural conversion of the firing system of the 600-MW unit G and the subsequent adaptation and optimisation of the steam-generator process.

Lab-scale assessment of different parameters influencing the operational behaviour of SCR-DENOX catalysts

Melanie Hilber and Harald Thorwarth

Currently the load profile of coal-fired power plants in Germany is changing due to the privileged input of electricity from renewable sources. As a consequence part-load operation of coal-fired units becomes more and more the dominant load regime. In this context, the investigation of SCR performance, not only at full load conditions, appears to be an important aspect. EnBW Kraftwerke AG set up a catalyst test rig for investigations at variable loads. The micro reactor was set up and designed according to VGB-R 302. First investigation results are presented.

Industrial scale assessment of the predictive quality of 3D-CFD model for SCR-DENOX catalysts

Benedetto Risio

A modelling approach for the mathematical description of the physical/chemical processes within SCR-catalysts is described. This modelling approach is embedded within the framework of a 3D-CFD environment (3D-CFD catalyst model). The 3D-CFD environment used in the present paper is the proprietary 3D-boiler simulation code RECOM-AIOLOS. The model was validated against full-scale operation data in the field and proved to accurately predict DENOX performance, mercury oxidation and SO2/SO3 conversion for a variety of different operation conditions applied during the measuring campaigns under consideration.

Topical challenges and status of lignite mining area rehabilitation in East Germany

Grit Uhlig

Since the German reunification in 1990 the lignite mining industry in former East Germany passed through a profoundly restructuring process. A contribution to the positive change in both Lusatian and Central German Mining district is given by this process. Remediation of 100,000 hectares of mining area, and restoration of a water balance over a surface area of approximately 390,000 hectares to an extensively self-regulating system are frequently labelled as Europe´s biggest restoration site. The remaining tasks related to the recultivation of the former mining areas bear a lot of technical and ecological challenges.