uu.seUppsala University Publications
Change search
ReferencesLink to record
Permanent link

Direct link
A Mathematical Model and Its Application for Hydro Power Units under Different Operating Conditions
Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
Show others and affiliations
2015 (English)In: Energies, ISSN 1996-1073, E-ISSN 1996-1073, Vol. 8, no 9, 10260-10275 p.Article in journal (Refereed) Published
Abstract [en]

This paper presents a mathematical model of hydro power units, especially the governor system model for different operating conditions, based on the basic version of the software TOPSYS. The mathematical model consists of eight turbine equations, one generator equation, and one governor equation, which are solved for ten unknown variables. The generator and governor equations, which are different under various operating conditions, are presented and discussed in detail. All the essential non-linear factors in the governor system (dead-zone, saturation, rate limiting, and backlash) are also considered. Case studies are conducted based on one Swedish hydro power plant (HPP) and three Chinese plants. The simulation and on-site measurements are compared for start-up, no-load operation, normal operation, and load rejection in different control modes (frequency, opening, and power feedback). The main error in each simulation is also discussed in detail. As a result, the model application is proved trustworthy for simulating different physical quantities of the unit (e.g., guide vane opening, active power, rotation speed, and pressures at volute and draft tube). The model has already been applied effectively in consultant analyses and scientific studies.

Place, publisher, year, edition, pages
2015. Vol. 8, no 9, 10260-10275 p.
National Category
Energy Engineering
URN: urn:nbn:se:uu:diva-262746DOI: 10.3390/en80910260ISI: 000362553000064OAI: oai:DiVA.org:uu-262746DiVA: diva2:855159

Correction in: Energies 9(6) Article number: 477 DOI: 10.3390/en9060477

Available from: 2015-09-18 Created: 2015-09-18 Last updated: 2016-08-10Bibliographically approved
In thesis
1. Dynamic Processes and Active Power Control of Hydropower Plants
Open this publication in new window or tab >>Dynamic Processes and Active Power Control of Hydropower Plants
2015 (English)Licentiate thesis, comprehensive summary (Other academic)
Abstract [en]

Hydro-electricity plays an important role in the safe, stable and efficient operation of electric power systems. Frequency stability of power systems refers to the ability to maintain steady frequency following a severe system upset resulting in a significant imbalance between generation and load. In order to suppress power grid frequency fluctuations, generating units change their power output automatically according to the change of grid frequency, to make the active power balanced again. This is the primary frequency control (PFC). PFC of electrical power grids is commonly performed by units in hydropower plants (HPPs), because of the great rapidity and amplitude of their power regulation.

A hydropower generation system is a complex nonlinear power system including hydraulic, mechanical, electrical and magnetic subsystems. Nowadays, the size of HPPs and the structure complexity of systems have been increasing, especially in China. The proportion of electricity generated by intermittent renewable energy sources have also been growing. Therefore, the performance of HPPs in terms of frequency control is more and more important. The research on control strategies and dynamic processes of HPPs is of great importance. The frequency stability of hydropower units is a critical factor of power system security and power quality. The power response time for evaluating the frequency regulation quality, is also a key indicator.

In recent years, there is a tendency that the new turbines experience fatigue to a greater extent than what seem to be the case for new runners decades ago, due to more regulation movements caused by increasingly more integration of intermittent renewable energy sources. In some countries, as in Sweden, PFC is a service that the transmission system operator buys from the power producers. In other countries, as in Norway and China, there is also an obligation for the producers to deliver this service, free of charge. However, there are costs related to this, e.g. due to design constraints and auxiliary equipment when purchasing a new unit or system, and due to wear and tear which affects the expected life time and maintenance intervals. Hence the specific research on wear and tear of hydro units due to PFC is exceedingly necessary. 

Place, publisher, year, edition, pages
Uppsala: Institutionen för teknikvetenskaper; Elektricitetslära, 2015. 53 p.
National Category
Engineering and Technology
Research subject
Engineering Science with specialization in Science of Electricity
urn:nbn:se:uu:diva-262768 (URN)
2015-10-19, Polhemsalen, Ångströmlaboratoriet (Ång/10134), Lägerhyddsvägen 1, Uppsala, 10:15 (English)
Available from: 2015-10-14 Created: 2015-09-20 Last updated: 2015-10-14Bibliographically approved

Open Access in DiVA

fulltext(1842 kB)23 downloads
File information
File name FULLTEXT01.pdfFile size 1842 kBChecksum SHA-512
Type fulltextMimetype application/pdf

Other links

Publisher's full texthttp://www.mdpi.com/1996-1073/8/9/10260

Search in DiVA

By author/editor
Yang, WeijiaSaarinen, LinnNorrlund, Per
By organisation
In the same journal
Energy Engineering

Search outside of DiVA

GoogleGoogle Scholar
Total: 23 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Altmetric score

Total: 187 hits
ReferencesLink to record
Permanent link

Direct link