Abstracts - VGB PowerTech Journal 6/2014

“Energiewende” and related challenges to system operations

Gunter Scheibner

The availability of a securely operated highvoltage grid is one of the basic conditions to guarantee the security of supply and to allow for a further development of electricity from renewable energy sources within the scope of the “Energiewende”. The results of 2013 and in particular the expected development of electrical installations from renewable energy sources and the according energy feed-in will continue to lead to dynamic changes in operational processes of the transmission system. The major operational challenges are related to the increasing gradients due to the high volatility of wind and PV feed-in, reaching already variations of production patterns above 1,500 MW in 15 minutes, and by the amount of measures to control the load flow situation on the German transmission grids and the increased need for control power to balance the system and keep frequency stable.

IT-aided planning and control of maintenance – prerequisite, first implementation and further potentials

Martin Stephan

Before implementing a computerised maintenance management system (CMMS), most potential users have already looked into some basic questions. But whatever the priorities may be, practical use proves that positive results will ensue as a mere effect of the necessary, consistent data base required by the various applications of a CMMS system. Also, with a CMMS system, the crucial key to an economical, strategy-oriented maintenance of equipment and components at power plants is established.

Boiler inspection with partial replacement of the refractory lining in a 20t/h biomass boiler

Tilmann Töpperwien

Since the beginning of 2008, Stadtwerke Düsseldorf AG has been running a biomass (waste wood) power station in the district of Garath for the environmentally-friendly production of electricity and district heating in a combined heat and power process. “Operation without permanent supervision” (72 Bob) was created and the operation of the power station is supervised by the central control department at the main power station located in the district of Hafen in Düsseldorf. The maintenance concept for the biomass boiler includes a biannual two-week shutdown and revision period, during which the necessary maintenance, cleaning and restoration work takes place. In 2013, after an operating time of almost 6 years, the refractory lining of the first boiler chamber was replaced.

Structured approach upon the replacement of power station components – frequency inverters in the Boxberg and Schwarze Pumpe power plants serve as examples

Peter Zander

The Vattenfall Europe Generation AG operates at the Boxberg, Jänschwalde, Lippendorf and Schwarze Pumpe sites lignite-fired power plants with a total capacity of 9,015 MW. The paper outlines the reasons for the procedure upon the replacement of components in the power plant. The individual steps of the retrofit project “Replacement of the coal mill frequency inverter at the Boxberg and Schwarze Pumpe sites” are being outlined which comprises comparison of variants, project planning, execution, strategies, quality assurance, service concept and results of a maintenance measure.

Requirements for the technical management of wind turbines in different European countries

Gerrit Schmidt and Yvonne Mosler

The term “technical management” in the field of wind energy covers a variety of services depending on the observers’ view. The technical management of wind turbines is an important and challenging task, which can be significantly crucial for the economic success of a wind turbine. While the wind conditions are not controllable, professional technical management affects profitability. Well maintained and constantly operating systems are the base to reach the estimated return on investment.

Holistic condition monitoring approach for wind turbines: from blade tips to generator bearings

John Reimers and Dietmar Tilch

More powerful wind turbine generators, larger rotors and therefore increased cost for each turbine erected lead to an increased focus on condition monitoring. Until now, each main component has been monitored by individual and specialised systems. A holistic system, as employed in conventional power plants, has not yet been deployed. The holistic approach raises synergies and enhances the detection accuracy of irregularities of the monitored components. In examples it will be shown how failure indications of one component maybe verified using the measurement results of other components.

Increased energy production by optimisation of yaw control

Jorgen Hojstrup

The exact alignment (Azimuth system) of a wind power plant is decisive for optimum electricity generation. Energy losses resulting from yaw misalignment in wind turbines can be considerable. A robust and reliable instrument for measuring the wind direction on the turbine much more accurately is presented: the spinner anemometer. The instrument has been thoroughly field tested and has been used to measure and correct for the misalignment on a large number of turbines. The next step in the development of the spinner anemometer is to document its capabilities for power curve measurements, making it possible for the wind turbine owner to check the performance of any of his turbines in any wind farm at any time.

The correlation between quality and safety – exemplified by the repair of a power cable in a 1.5 MW wind turbine

Walter Sucrow

Safety experts indicate for a long time that there is an inseparable relation between safety and quality, because nobody is able to deliver a good safety performance but a bad quality performance at the same time and vice versa. This finding is very slowly accepted in the wind business because it is a very young business and the traditional stakeholders of this business are neither familiar with the energy sector nor with the plant engineering sector. This will be demonstrated in this article based on the example of a defect power cable in a 1.5 MW turbine. By means of this turbine, which had been in operation for 12 years, it can be demonstrated how slow the state of the art finds its way into this technology, respectively how relevant is the temptation to implement fast and cheap maintenance solutions with low technical standards and insufficient results.

Oil purity as a basic quality gate in the maintenance process of gearboxes

Daniel Keller

Oil has a decisive influence on the life expectancy of a gearbox. ISO 4406 (1999) provides a way to measure the quality of oil. In an oil sample of 1 ml all foreign matter and particles are counted and classified in three dimensions >4 µm, >6 µm and >14 µm. The maintenance of gearboxes is characterised by high technical complexity with a high accuracy and quality. Therefore, the Maintenance and Engineering Center of RWE Power AG controls at two quality gates the specified oil cleanliness. Both in a nonload test run and during the testing of a gearbox under load, the quality of the oil is measured. The biomass technology roadmap of the RHC-platform: priorities for high efficient large-scale CHP units Panagiotis Grammelis, Niall Goodwin, Eija Alakangas, Walter Haslinger and Emmanouil Karampinis The European Technology Platform on Renewable Heating and Cooling (RHC-Platform, www.rhc-platform.org) is an initiative aiming to foster research, development and innovation in the renewable heating and cooling sector ofthe EU. The Biomass Panel of the RHC-Platform has defined research priorities aiming to reach certain key performance indicators for different biomass value chains. The present paper presents the key research priorities and targets for the value chain components of most relevance to the power sector: sustainable and cost-efficient biomass feedstock supply, thermally-treated biomass fuels and highly efficient large-scale CHP plants.

The turnaround in energy policy remains on dead-end street Amendment of German Renewable Energy Act (EEG) does not meet important targets

Dietrich Böcker and Dietrich H. Welte

Although the German Government has just tried to amend the EEG to “EEG 2.0”, the Ger-man turnaround in energy policy still remains on a dead-end street because the act was not generally revised. The priority feed-in of renewables and the related tariff policy were not re-placed by market rules. Thus, the costs will continue to rise and the turnaround in energy policy remains a permanent construction site. Instead of dealing with issues how to allocate costs, politics should rather have dealt with a reduction of costs caused by its energy policy, limitation of the waste of economic resources and a realistic long-term strategy without clinging to a doubtful pioneering role.