Ryszard Malewski, Jan Subocz, Marek Szrot, Janusz Płowucha, Rafał Zaleski
The basis to assess a transformer modernization remunerativeness
Described are general market conditions stimulating revitalization of power network assets belonging to distribution companies and electric power firms. Presented are the most important methods allowing to carry out the technical state complex evaluation and analysed are main technical and economical modernization cost elements which can help in decision processes concerning transformer population management. Deciding whether to replace or only modernize the transformer is a vital thing when you plan your company budget but it needs carrying out the transformer technical state specialized tests.
Stanisław Łopata, Kamil Kwintowski
Capacitive sensors used for high-pressure steam pipeline creepage control
Technical state and exploitation usefulness assessment of high-pressure steam pipelines needs permanent creepage process control. It helps in the object elements replacement planning as well as it ensures the optimum material usage. Laboratory and industrial test results of capacitive CERL-Planer and Interatom type sensors show their usefulness in steam pipelines creepage control. Their essential advantage is the possibility to measure creepage distorsion during running the pipeline i.e. with no shutting it down, which is needed when you use, for instance, measuring trunnions. Capacitive sensors can be installed not only on straight pipeline sections but also on bent elements, giving the possibility to control them, which is rather rare in our national power system.
iase bulletin
Jan Bujko, Łukasz Szczepaniak
Increasing the efficiency of load frequency control in disturbance conditions
of electric power system's operation
The paper presents the influence of the tie-line frequency bias coefficient which is set in the LFC controller on the secondary control. The optimal value of this coefficient enables the proper control in the case of greater disturbances in electric power system.
Magdalena Borgosz-Koczwara, Aleksander Weron, Agnieszka Wyłomańska
Symulations of the bidding strategies on the power market
In this paper we apply a new approach to build bidding strategies for power suppliers on electricity market and assume that each supplier's bid is a linear function. Moreover each supplier tends to maximise his profit and minimize his risk, which are dependent on the generation output, coefficients of bid function and cost function. Moreover, supplier's profit is dependent on strategies of the other players. Therefore suppliers' decisions are the subjects to expectations of the rivals' bids and playing at electricity market is connected with the imperfect information about decisions of the rivals ([1]). We extend the approach used in [4] and [7] and for some examples of load forecasting we obtain the optimal suppliers' bids. The main results are illustrated by the numerical examples. To the analysis we use the real data from the Nord Pool power exchange.
Adam Misiorek
Heavy-tailed distributions in power demand modelling
ARMA type linear time series (and more precisely – corresponding with them long AR type series) are used for modelling power demand process stochastic component (system wide load) in California. Like it was described in previous papers the seasonal variation technique to remove seasonality (i.e. deterministic component) had been used. But the novelty is an estimation of the mentioned time series parameters, taking into account heavy-tailed noises i.e. the ones described by hyperbolic, NIG or stable distributions.
Magdalena Borgosz-Koczwara
CEPRIN – Centre of promoting the innovations in power industry
The main goal of the improvement of competitivity in Lower Silesia's economy is to make it „knowledge-based economy". It can be achieved by development of companies' innovative activity, close cooperation between science and economy sectors and strengthening the institutions which are helpful to enable that cooperation. One of such institutions is CEPRIN – Centre of Promoting the Innovations in Power Industry, partially financed from EU Structural Funds and National Budget.
Magdalena Borgosz-Koczwara
„ABS-CLUSTER" Innovative cluster to ensure power security for Lower Silesia
Institute of Power System Automation runs the EU project called: „ABS-cluster – formation of an innovative cluster to ensure power security for Lower Silesia. Analysis, studies, simulations". The project is partially financed from EU Structural Funds and National Budget. The article presents aims and goals of the project and emphasizes the need to form such cluster for the good of Lower Silesia.
power industry Akademy
Stanisław Cader, Bogumił Dudek, Roman Fober, Tadeusz Gontarz, Witold Wiśniewski
Session 7 – Live line works carried out on electric power units and installations – Twelfth lecture – Live line works in 110, 220 and 400 kV lines
Live line works in Polish 110 kV lines are carried out according to the distance method (French method). Live line works in the 220 and 400 kV are carried out according the method – „at the potential". Works carried out with the traditional methods can be supplemented with the use of helicopters in order to enhance their effectiveness and security. The technology of the live line works in UHV substations is dynamically developed in the world in last years.
Pro Novum bulletin
Ewa Zbroińska-Szczechura, Jerzy Dobosiewicz
Influence of boiler operationg conditions on secondary steam superheater pipe-coils durability
The majority of superheater pipe-coils damages are due to the loss of wall thickness. The direct cause of it is the high-temperature corrosion. Most often damaged are elbows of girding and enveloping pipe-lines exposed directly to the furnace gas jet and it usually happens to pipe-lines in low-emission furnace power-boilers.
Jerzy Trzeszczyński
Thermal shock as a factor limiting the lifetime of pressure components operated under creep conditions
Under standard operating conditions the lifetime of the components operated at creep temperatures mainly depends upon how far the creep process has already been advanced. Under real conditions, however, the creep phenomenon is very often accompanied by the other ones likely to considerably reduce the lifetime of the components. One of such additional phenomena is thermal shock which can drastically limit the fitness for purpose of the component operated at creep temperature. This paper describes most common causes of thermal shock generation, methods of thermal shock detection as well as how such a phenomenon can be prevented or mitigated.
Sławomir Rajca, Emil Pizon, Krzysztof Brunné
Selected experiences connected with the examination of material condition within the area of rotor disk grooves
The examination is applied to the grooves of HP and IP rotor disk operating above the limit temperature as well as of LP rotors whose disks operate in Wilson zone where dry steam is transformed into the wet one. To avoid serious damage and breakdowns of turbines the above components shall be subjected to diagnostic examination. The most frequently applied examination methods depending upon the blades fixation are: dye-penetrant or magnetic examination, ultrasonic examination. This paper presents selected own experience gained on the basis of nondestructive and metallographic
Wojciech MURZYNOWSKI, Ewald GRZESICZEK
The effect of geometry and MES calculating simulations on the results of the analysys of stress in the rotor disk rims
Rotors are undoubtedly the most critical components of the turbine. Having in view a high cost of replacement on the hand and limited possibilities of repair on the other hand, the extension of safe operation time of the rotor is of vital importance for the possibility and conditions of further operation of the turbine. Due to different structural, technological and material features encountered in the design of rotors as well as their different service conditions the problem of their lifetime expectancy can be generalized to a small degree only. In this paper arguments are presented in favour of a customized approach to the lifetime of rotors. Areas and causes of the defects on the rotor disk are indicated. Test methods and some possibilities of defect prevention and repair are discussed.
Wojciech Klepacki
The influence of water blowers on thermal stresses in boiling tubes waterwalls
Steam boiler operating experience shows that the most effective boiling tubes descaling method is to use water blowers. However, it is proved that this type of cleaning has a very negative influence on boiling tubes durability because of thermal stresses that arise during the process. One of the ways to reduce this influence (thermal cracks) is to limit the use of this method to some really indispensable cases. Moreover, it is also possible to use hot water for this purpose that will considerably reduce stresses arising in boiling tubes.
power industry and ecology
Monika Poskart, Lech Szecówka, Henryk Radomiak
The influence of co-burning of solid, liquid and gaseous biofuels on NOx concentration during the process of reburning
As a result of some investigations we know that the use of biofuels in the process of reburning is an effective method to reduce the nitric oxides concentration. The most effective of all analysed biofuels is the synthetic biogas, and among solid fuels – hay. High effectiveness of the synthetic biogas results from its composition; first of all high methane contents which has a big affinity to form hydrocarbon radicals, while in case of solid fuels the contents of volatile particles has also a big influence. Adding of the synthetic biogas in various quantities confirmed that for one chosen fuel of constant chemical constitution the quantity of heat added to the process can be of a fundamental importance to NOx concentration reduction efficiency.