This study focuses on small scale Hydropower in Sweden. This means plants with a capacity of up to 10 MW. The study has a special focus on plants with a capacity up to 2 MW. The study has three aims. It strives to describe the small-scale hydroelectric industry in Sweden.

This master thesis covers the seasonal planning of a small scale Hydropower system. The system in this study is owned and operated by Mälarenergi Vattenkraft AB. The total system consists of 4 different main rivers with 24 Hydropower stations and several dams. The total installed power in the system is 43.75 MW. Most of the Hydropower stations are regarded as small scale Hydropower stations and thus entitled to green certificates.In this report the issue of planning is formulated as an optimization problem.

Flow measurement is one of the greatest challenges in order to calculate efficiency in Hydropower. Most Hydropower plants in Sweden use differential pressure methods for flow measurement. These methods are dependent on constant conditions in the waterways. A change in these conditions, like turbine improvements, prevents differential pressure methods to verify efficiency improvements. Since efficiency improvements can?t be verified by one measurement system, another method, which isn?t affected by changing conditions, can be used.

This master thesis has been performed at Vattenfall Power Consultant in Gothenburg and Trollhättan for Vattenfall Vattenkraft. In this report vacuum circuit breaker in small-scale Hydropower stations with the rated power 4 MVA and below has been studied. Models of the stations are modeled and analyzed in PSCAD/EMTDC to study the high voltage transients that are created after current chopping with vacuum circuit breaker. Vacuum circuit breaker may chop the current before it reaches zero value, which means that high voltage transients can be created. The equipment of the stations can be destroyed by high voltage transients.The purpose of this thesis is to examine the use of vacuum circuit breaker in small-scale Hydropower stations and the risk for high voltage transients from current chopping.According to the results there is a risk of high voltage transients after current chopping with small synchronous generators in stations with the operating voltages 0.4 kV and 3.6 kV.

Small Hydropower plants have been an important source for electricity for many years. During the 70?s the general thought was that nuclear was the future. Around 2000 small waterpower plants were shut down. It wasn?t profitable to invest in.

In Sweden there are 1894 small-scale Hydropower plants in operation, which together generate 4.3 TWh of electricity per year according to Swedish Hydropower compound (SVKF, 2011). This corresponds to the annual consumption of about 860,000 Swedish households (based on an annual consumption of 5000 kWh). In the mid-1950s there were around 4000 small-scale Hydropower plants in operation in Sweden before cheap fossil fuels and uranium competed with them, in the current situation only 1,894 of these are in use. If slumbering small Hydropower plants once again would be taken into use and some new ones are built, we would be able to extract about 7 TWh of renewable electricity from these annually in Sweden, representing about 1.4 million households.The thesis intends to calculate and construct a hydroelectric power plant at the existing dam in Olofsfors and give suggestions on how the power station should run during the time that fish migration is greatest in Leduån.The turbine and generator to the station in Leduån at Olofsfors is designed by the height of the fall and the water flow through the dam. The turbine selected for the station is a CK-1000RM turbine with a 4-pole 250 kW generator from Cargo & power turbine Sweden AB, which is expected to deliver 1.2 GWh per year.

This master thesis was made to validate Hydropower models of a turbine governor,Kaplan turbine and a Francis turbine in the power system simulator ARISTO atSvenska Kraftnät. The validation was made in three steps. The first step was to makesure the models was implement correctly in the simulator. The second was tocompare the simulation results from the Kaplan turbine model to data from a realHydropower plant. The comparison was made to see how the models could generatesimulation result that was similar to the reference power station.

The report begins with a general inventory of possible technical faults in a Hydropower plant and of possible fault indicating measurements. Then an investigation is made concerning a few different faults. Based on this investigation a choice on seal box condition and water leakage is made as problem for a more thorough examination, in which it is concluded that the turbine water leakage is larger when the turbine is put into operation. The examination ultimately results in a computer alarm for faults related to the seal box. Finally a few things are mentioned about flow measurement and pressure measurement in relation to the project as a whole..

This master thesis was made to investigate the possibilities of using the Matlab-basedsoftware Basegrain to determine grain size distributions of erosion protections onHydropower dams. Basegrain is a photogrammetric tool developed to generate grainsize distributions and other information about coarse flood sediments by analyzing adigital photo of the stone bed. The investigation was made by validating the ability forBasegrain to assess grain size distributions of various materials smaller than the blocksused in an erosion protection by comparing sieving results or manual measurementswith the results obtained by the program. A statistical comparison was then made bycomparing the results from sieving and the program. The possibilities of using thesame method on existing Hydropower dams were then investigated by determiningwhether the method was practically viable or not.The results showed that Basegrain generated grain size distributions for coarse gravelthat were very close to the sieving results.

Vattenfall AB is a large producer of electric energy where approximately half of the energy comes from Hydropower. Vattenfall Hydropower has got almost a 100-year old history and the company has developed a lot since 1909. After that the number of power plants increased and the competition got more intense, there were higher demands on the reliability. One way to secure the reliability with a good satisfaction at the power plants is to implement a maintenance method named Reliability-Centred Maintenance. RCM is a result of the introduction of the complex aeroplane Boeing 747 in the 1960?s.

During the migration season in 2013 a study on spawning migrating salmon and the effect of water flow on the behavior was conducted of the salmon at the Forshaga Hydropower station in the River Klarälven. The River Klarälven with its nine Hydropower plants on the Swedish side, constituting migration obstacles for the migrating salmon. Fortum Generation AB has together with the County Administrative Board restored a salmon trap at the lowermost Hydropower station in Forshaga, aiming at making it possible for the salmon to swim into the trap, and thereafter be transported by truck past the power plants and then continue their journey to the spawning grounds on their own. Unfortunately, it is believed that the trap does not work as well as it should. In this study, I focused on salmon position in relation to water flow and if the number of salmon that swam into the fish trap differed between salmon with previous experience of the trap (experienced) and salmon without experience (unexperienced).

Vattenfall and Svenska Kraftnät perform start-up tests, where Hydropower generators are used to power up the electrical grid in case of a blackout. To monitor the electrical grid, Phasor Measurement Units (PMU) are used. Each PMU is individually equipped with a GPS-receiver to precisely timestamp the data relative to the official time UTC. During the test, it is also of interest to timestamp the measurement signals from individual Hydropower generators to later compare with PMU-data, and thus study the power grids impact on the generator. The aim is to work out an appropriate method to make these measurements and to build a data acquisition system, capable of timestamp data relative to UTC, from a generator in one of Vattenfalls hydroelectric power stations. The problem is that the generator is located in an underground station which hampers the reception of GPS-signals and wiring should be avoided if possible. Time synchronization has been solved by using Vattenfalls network, which is synchronized by the network protocol NTP.

This master thesis is a study of the Swedish Hydropower capacity to balance wind power. The Swedish government has decided that it should be possible to produce 30 TWh from wind power in the year 2020. The Swedish municipalities have to have plans for wind power plants with total yearly generation of 30 TWh. Wind power is an variable energy source that needs to be balanced by other energy sources. In Sweden the Swedish Hydropower can be used for balancing a large scale introduction of wind power.

This master thesis is a study of the Swedish Hydropower capacity to balance wind power. The Swedish government has decided that it should be possible to produce 30 TWh from wind power in the year 2020. The Swedish municipalities have to have plans for wind power plants with total yearly generation of 30 TWh. Wind power is an variable energy source that needs to be balanced by other energy sources. In Sweden the Swedish Hydropower can be used for balancing a large scale introduction of wind power.

Sydkraft Vattenkraft AB owns and operates the Traryd Hydropower plant, located in the river Lagan in the southern part of Sweden. The gravity dam is classed according to RIDAS guidelines (Hydropower Industry Dam Safety Guidelines) as a class 1B dam. This means that the dam must discharge a class 1-flow which has a return period of 10 000 years. The inflow into the dam has been calculated in an earlier report to 495 m3/s, with a waterline at an elevation of 126, 3 meters above sea level. The gravity dam has a discharge system with two rectangular weirs, which results in a smaller discharge than the necessary 495 m3/s.