| |
|
|
|
|
|
|
|
|
1. |
Record Nr. |
UNINA9910139552003321 |
|
|
Autore |
Hofmann Wolfgang <1945-> |
|
|
Titolo |
Reactive power compensation [[electronic resource] ] : a practical guide / / Wolfgang Hofmann, Jürgen Schlabbach, Wolfgang Just |
|
|
|
|
|
|
|
Pubbl/distr/stampa |
|
|
Chichester, West Sussex, U.K., : Wiley, 2012 |
|
|
|
|
|
|
|
ISBN |
|
1-119-96778-3 |
9786613619242 |
1-280-58941-8 |
1-119-96728-7 |
1-119-96727-9 |
|
|
|
|
|
|
|
|
Descrizione fisica |
|
1 online resource (304 p.) |
|
|
|
|
|
|
Altri autori (Persone) |
|
JustWolfgang |
SchlabbachJ (Jürgen) |
|
|
|
|
|
|
|
|
Disciplina |
|
|
|
|
|
|
Soggetti |
|
Capacitors |
Electric action of points |
Electric capacity |
Reactance (Electricity) |
|
|
|
|
|
|
|
|
Lingua di pubblicazione |
|
|
|
|
|
|
Formato |
Materiale a stampa |
|
|
|
|
|
Livello bibliografico |
Monografia |
|
|
|
|
|
Note generali |
|
Description based upon print version of record. |
|
|
|
|
|
|
Nota di bibliografia |
|
Includes bibliographical references and index. |
|
|
|
|
|
|
Nota di contenuto |
|
REACTIVE POWER COMPENSATION; Contents; Foreword and Acknowledgements; 1 Basics of Reactive Power; 1.1 Chapter Overview; 1.2 Phasors and Vector Diagrams; 1.3 Definition of Different Types of Power; 1.4 Definition of Power for Non-Sinusoidal Currents and Voltages; 1.5 Equivalent Mechanical Model for Inductance; 1.6 Equivalent Mechanical Model for Capacitance; 1.7 Ohmic and Reactive Current; 1.8 Summary; References; 2 Reactive Power Consumers; 2.1 Chapter Overview; 2.2 Reactive Energy Demand; 2.3 Simplified Model: Series Reactive Power Consumer |
2.4 Realistic Model: Mixed Parallel and Series Reactive Power2.5 Reactive Power Demand of Consumers; 2.5.1 Asynchronous Motors; 2.5.2 Transformers; 2.5.3 Control Gear (Ballast) for Gas Discharge Lamps; 2.6 Summary; 3 Effect of Reactive Power on Electricity Generation, Transmission and Distribution; 3.1 Chapter Overview; 3.2 Loading of Generators and Equipment; 3.3 Power System Losses; 3.4 |
|
|
|
|
|
|
|
|
|
|
|
Generators; 3.5 Voltage Drop; 3.5.1 General; 3.5.2 Transferable Power of Lines and Voltage Drop; 3.5.3 Transformer Voltage Drop; 3.6 Available Power of Transformers; 3.7 Summary |
4 Reactive Power in Standard Energy Contracts4.1 Chapter Overview; 4.2 Introduction; 4.3 Reactive Energy to be Considered in Standardized Contracts of Suppliers; 4.3.1 Pricing Dependent on Consumed Reactive Energy (kvarh); 4.3.2 Pricing Dependent on Consumed Apparent Energy (kVAh); 4.4 Importance of Reactive Power in Determining the Costs of Connection; 4.5 Summary; Reference; 5 Methods for the Determination of Reactive Power and Power Factor; 5.1 Chapter Overview; 5.2 Methods; 5.2.1 Determination of Power Factor in Single-Phase Grids |
5.2.2 Direct Indication of Power Factor by Means of Brueger's Device5.2.3 Determination of Power Factor in Three-Phase System; 5.2.4 Determination of Power Factor Using Portable Measuring Equipment; 5.2.5 Determination of Power (Factor) via Recorded Data; 5.2.6 Determination of Power Factor by Means of an Active Energy Meter; 5.2.7 Determination of Power Factor by Means of an Active and Reactive Energy Meter; 5.2.8 Determination of Power Factor via the Energy Bill; 5.3 Summary; 6 Improvement of Power Factor; 6.1 Chapter Overview; 6.2 Basics of Reactive Power Compensation |
6.3 Limitation of Reactive Power without Phase Shifting6.4 Compensation of Reactive Power by Rotational Phase-Shifting Machines; 6.5 Compensation of Reactive Power by Means of Capacitors; 6.6 Summary; 7 Design, Arrangement and Power of Capacitors; 7.1 Chapter Overview; 7.2 Basics of Capacitors; 7.3 Reactive Power of Capacitors; 7.4 Different Technologies in Manufacturing Capacitors; 7.4.1 Capacitors with Paper Insulation; 7.4.2 Capacitors with Metallized Paper (MP Capacitor); 7.4.3 Capacitors with Metallized Plastic Foils; 7.5 Arrangements and Reactive Power of Capacitors |
7.5.1 Capacitors Connected in Parallel |
|
|
|
|
|
|
Sommario/riassunto |
|
The comprehensive resource on reactive power compensation, presenting the design, application and operation of reactive power equipment and installations The area of reactive power compensation is gaining increasing importance worldwide. If suitably designed, it is capable of improving voltage quality significantly, meaning that losses in equipment and power systems are reduced, the permissible loading of equipment can be increased, and the over-all stability of system operation improved. Ultimately, energy use and CO2 emisson are reduced. This unique guide discusses the effects of reactive po |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
2. |
Record Nr. |
UNINA9910875588303321 |
|
|
Titolo |
PISA 2022 : Analyse der Bildungsergebnisse in Deutschland / / Doris Lewalter, Jennifer Diedrich, Frank Goldhammer, Olaf Köller, Kristina Reiss |
|
|
|
|
|
|
|
Pubbl/distr/stampa |
|
|
|
|
|
|
ISBN |
|
|
|
|
|
|
Edizione |
[1st ed.] |
|
|
|
|
|
Descrizione fisica |
|
1 online resource (334 p.) |
|
|
|
|
|
|
Soggetti |
|
Schulleistungsstudie |
PISA-Schock |
Programme for International Student Assessment |
Mathematik |
mathematische Kompetenz |
Empirische Bildungsforschung |
Pädagogische Psychologie |
Schulpädagogik |
|
|
|
|
|
|
|
|
Lingua di pubblicazione |
|
|
|
|
|
|
Formato |
Materiale a stampa |
|
|
|
|
|
Livello bibliografico |
Monografia |
|
|
|
|
|
Sommario/riassunto |
|
Im Rahmen der achten Erhebungsrunde des Programme for International Student Assessment (PISA) wird erneut der Stand der funktionalen Grundbildung von Jugendlichen in den Bereichen Mathematik, Naturwissenschaften und Lesen untersucht sowie der (außer-)schulische Kontext des Lernens und Lehrens betrachtet. Der Schwerpunkt in PISA 2022 lag auf der mathematischen Kompetenz, für welche die Rahmenkonzeption überarbeitet wurde. Mithilfe der PISA-Studien wird untersucht, inwiefern es Bildungssystemen gelingt, Schüler*innen am Ende ihrer Pflichtschulzeit auf weiterführende Bildungs- und Berufswege vorzubereiten. Dieser Berichtsband präsentiert die Bildungsergebnisse Fünfzehnjähriger in Deutschland im Vergleich zu Schüler*innen aus anderen Staaten. Auf nationaler Ebene werden die Kompetenzen und motivational-emotionalen |
|
|
|
|
|
|
|
|
|
|
Orientierungen der Jugendlichen auch in Bezug zu relevanten Merkmalen wie Geschlecht, besuchter Schulart sowie ihrer sozialen Herkunft und ihren Zuwanderungshintergrund betrachtet. Trendanalysen geben interessante Einblicke in die Entwicklung der Kompetenzen der Schüler*innen sowohl seit der letzten – und gleichzeitig präpandemischen – Erhebungsrunde 2018 als auch in die langfristige Entwicklung über 10 Jahre, als Mathematik das letzte Mal Hauptdomäne war. Abschließend werden Befunde zum Lehren und Lernen während der Pandemie berichtet. |
|
|
|
|
|
| |