Abstracts - VGB PowerTech Journal 8/2011

Impact of intermitting generation on power system stability

Joachim Lehner and Dominik Schlipf

In order to achieve the goal of the European Union (EU) to cover 20 % of primary energy consumption by renewable energy sources until 2020, the penetration of renewable electricity generation must be significantly increased in comparison to the current level. The integration of the increasing share of intermitting generation, while maintaining the present security level of supply, confronts the existing power system with a big challenge. The limits are to be revealed within the scope of a research project initiated by VGB. Among others, the issues are to be settled how to shift the limits by different measures like more flexible conventional generation, integration of energy storage, grid extension or deliberate load management.

Filtering of system frequency as input signal for primary control - Advantages and disadvantages for power pants and power systems

Tobias Weißbach and Ernst Welfonder

The permanent unsystematic connection and disconnection of loads leads to a random noise behaviour of the active power balance within the electric power system, which results in a permanent network frequency noise by reason of deceleration and acceleration of the rotating masses. This frequency noise causes ongoing actuations of the proportionally regulated elements in primary controlled power generation units. In order to avoid these actuations, the network frequency is smoothed before entering the primary controlling elements applying non-linear dynamic filters.The paper highlights the advantages and disadvantages of frequency filtering from the points of view of power generation units and the grid respectively under consideration of national and European network code requirements. Additionally, rules for the appropriate set-up of filter parameters are derived with regard to the mostly used filter configuration.

Ratio between conventional and renewable energy production in Germany with focus on 2020

Christian Ziems, Harald Weber, Sebastian Meinke, Egon Hassel and Jürgen Nocke

The increasing influence of renewable power production into the existing electrical energy supply system leads to displacement of conventional power production. This also results in reduced inertia with negative effects on system stability. Investigations are required to examine the maximally possible integration of renewables-based power and adjusted modes of operation of conventional power plants and the effects on lifetime and efficiency.

Monitoring & Diagnostics in power plants

Ulrich Immler and Dylan Zhao

Failure of critical power plant equipment is usually something plant owners need to avoid at all costs. The use of monitoring and diagnostic (M&D) systems helps giving an early indication of potential problems of key plant equipment such as turbines, generators and boilers. The resulting preventative maintenance strategies contribute to avoid unexpected equipment failure. Indeed there is a particular need for such systems in older plants that do not have modern M&D systems but are operating ageing equipment that is more likely to fail.

Functional safety management of thermal power plants from the I&C perspective of an energy provider

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, electronical and programmable electronical equipment (E/E/PES) within safety equipment. The requirements of the applied safety systems for the entire life cycle, beginning with a concept study regarding overall safety requirements (HAZID) up to the decommissioning of the safety-systems, will be provided.

Reduction of turboset stresses by installation of the power plant decoupling protection device

Matthias Humer, Leslaw Golebiowski and Stefan Kulig

Grid disturbances can cause torsional vibrations of a turbo set shaft train which may reduce the lifetime or lead to serious mechanical damage also in the stator end windings of the generator. Because of this it is very desirable not only to have a permanent online monitoring system for torsional vibrations, but it is also of high interest to have a protection device. Stress-induced disturbances can be reduced through the application of a protection system that can selectively decouple the turbo-set off the grid after a pre-set short circuit period.

Monitoring of the water/steam cycle: Transforming data into information for action

Frank G. de Vos, Rob Heijboer and Marga van Deelen

It is common practice to comprehensively monitor the water-steam cycle to ensure the required chemical mode of operation and to avoid plant damage. This does not only involve information measured data and installations but also the reliability of the measurements made and the transfer of the data into information. Several case studies will be presented to support the importance of transforming data into information to take the proper action.

Computer-aided optimisation of the gas-particle flow at the Duisburg circulating fluidised bed furnace

Martin Weng, Michael Nies and Joachim Plackmeyer

Computer-aided simulation of gas flow and combustion has become a well-established analysis and optimisation tool for power plant engineering. However, the simulation of fluidised beds is still a challenging task due to the physical complexity of dense particle flows. The article presents the 3-dimensional multiphase particle-in-cell (MP-PIC) simulation of combusting gas and particle flow within the Duisburg 250 MW Circulating Fluidised Bed Combustion chamber (CFBC).

Thermodynamic investigations in power plants

Richard Kitzberger and Ralf-Roman Schmidt

It is common within the inspection of newly built thermal power plants and after retrofit measures to contemplate the whole process as a “black box”. This approach can comprise the risk that immanent uncertainties of measurement are regarded in favour of the contractor. If the acceptance tests are carried out in accordance with the Guideline VDI 2048, fundamental balances are modelled for the whole plant and closed through measurements in neuralgic places. Thus, measurement uncertainties can be minimised and the most likely condition of the plant can be determined.

The analysis of film-forming amines - Methods, possibilities, limits and recommendations

Katrin Stiller, Tobias Wittig and Michael Urschey

Treatment concepts of the water-steam-cycle based on film forming amines are attracting increased attention due to their advantageous properties. This type of treatment requires a reliable and under field conditions simple analytical method for the determination of the free (not surface bound) proportion of the amine. Due to the intrinsic physicochemical properties of film forming amines, this is not a trivial task. An overview of common determination methods on the market is given. Recommendations are given regarding the sampling and rinsing procedures and the necessary quality of the dye.

A new device for the assessment of the mechanical stability of IEX resins

Dieter Mauer

For measurement of the breakage force of IEX beads so far the Chatillon test was applied. The scattering of the breakage force only provided limited information. With suitable mathematical evaluations additional results like shore, crosslinking degree and geometrical breakage ellipticity can be derived by a new procedure.

SIL - The right way to achieve functional safety?

Hans Christian Schröder, Andre Günther, Karsten Klingler and Thomas Leidel

Power plants can only be operated in a safe, reliable and cost-effective way if central process control systems are implemented and comply with the relevant safety requirements. The ultimate goal in this context should be to establish effective system architecture. Effective implementation in practice of “SIL (Safety Integrity Level) requirements” for safety-related components must take into consideration the operation of the respective plant and its context. Operators are recommended to analyse the contents of SIL certificates and look at the basis of SIL determination.

Methods for accident analysis - A paradigm shift

Katrin Weißenborn

Different methods of accident investigation are compared and presented. The development of accident analysis from root cause to accident consequences is highlighted. Measures are focussed which would have avoided the accident. Apart from technical issues, the paper also deals with wrong organisational development. The investigation method supports a learning company culture that is concentrating on staff health.

Work safety and health protection in biomass combustion plants

Herbert Lindner

Handling of biomass in combustion plants places certain demands on occupational safety and health protection of personnel. Fuels, plant chemicals and by-products are taken as examples to outline which rules and regulations have to be applied in terms of operational safety, hazardous materials, explosion protection, bio materials and radiation protection. Adopted to the specific needs of a plant, supplements will be required. These are to be implemented in companies by application of the tools.