The theme of this thesis is the supply of capacity during peak demand in restructured power systems. There are a number of reasons why there is uncertainty about whether an enegyonly electricity market (where generators are only paid for the energy produced) is able to ensure uninterrupted supply during peak load conditions. Much of the public debate in Europe has been about the present surplus generation capacity. However, in a truly competitive environment, it is hard to believe that seldom used capacity will be kept operational. This is illustrated by developments in Sweden. For this reason, the large surplus of generation capacity in the European Union may vanish much faster than generally assumed. In the USA, much of the debate has been about California. During the last three summers, California has occasionally experienced involuntary load shedding and prices have been very high during these periods. To some extent, the Californian situation illustrates the relevance of the subject of this thesis: in a deregulated system generators may not be willing to invest in peaking capacity that is only needed occasionally, even though prices are very high during these periods. A good solution to the problem of providing peaking power is pivotal to the success of power market restructuring. Solutions that fail to create the right incentives will result in unacceptable load shedding and can endanger the whole restructuring process. On the other hand, solutions that pay too much for investments in peaking power will lead to generation capacity surpluses and thus represent a societal loss. Why is peaking capacity a problematic issue in energy-only markets? Traditionally, probabilistic methods are applied to calculate the required generation capacity to obtain a desired level of reliability. In a centrally planned system, this level of generation capacity is developed in a least-cost manner. A single utility or central authorities can thus control the level of reliability directly. This is not possible in a market-based system, if suppliers are only paid for the energy produced. Under the assumption of certainty and continually varying prices, generators fully recover their variable and investment costs under ideal market conditions. When uncertainty is taken into account, generators will cover their expected costs. However, revenues will be extremely volatile, especially for peaking generators. Combined with a risk-averse attitude, it is unlikely that investments will be sufficient to maintain the traditional level of reliability in an energyonly market. Consequently, one would expect reserve margins to decline in such markets. This effect is very clear in Sweden that deregulated in 1996, and less explicit in a number of other cases like Norway, California and Alberta. Pricing and Consumer Preferences The theory of electricity pricing was originally developed for vertically integrated utilities, but elements from this theory are also valuable in a restructured context. Many authors have agreed on the presence of a capacity element in the optimal price during peak-load conditions, while price should equal marginal cost during low-load conditions. An important assumption is that prices have to be stable. More recently, spot pricing of electricity has been advocated. A number of papers have been written about how to efficiently include security considerations in the spot price. Because the availability of capacity cannot be directly controlled in an energy-only spot market, the probability of occasional capacity shortages increases. It is important to be prepared for this situation. The core of the problem is that demand is de facto inelastic in the short-term because of traditional tariff systems. It is shown that considerable economic gains are obtained when demand elasticity can be utilized, even if only minor shares of demand are elastic in the short-term. Better utilization of demand elasticity was also profitable in traditional systems, but after restructuring the gain is much larger: the alternative is not expensive generation but random rationing, which is unacceptable in modern society. It is possible to go one step further. Consumers have different preferences for the use of energy and reliability. Some consumers have a low tolerance about being disconnected, while others are more willing to accept this. This will be reflected by their willingness to pay for reliability. A better solution would emerge if consumers could buy electricity and reliability more or less as separate commodities, based on their preferences. In the context of pricing it should be pointed out that ”profile-based settlement” that allows small consumers to freely choose their supplier without hourly metering is detrimental with respect to the correct pricing of capacity. It should only be used in the initial phases of opening a market. Improved utilization of system resources Even in the short-term, demand and the availability of generation and transmission resources are uncertain. Therefore, it is necessary to have reserves available in a power system. When capacity becomes scarce, it is difficult to satisfy the reserve requirements. If these requirements are strict, the only possibility is to resort to what can be called ”preventive loadshedding” to satisfy the reserve requirements. This is obviously an expensive solution, but there are no obvious ways of balancing the (societal) cost of preventive load shedding against reduced system security. In this thesis, a model is developed for unit commitment and dispatch with a one-hour time horizon, with the objective of minimizing the sum of the operation and disruption costs, including the expected cost of system collapse. The model is run for the IEEE Reliability Test System. It is shown that under conditions where there is not enough capacity available to satisfy the reserve requirements, large cost savings can be obtained by optimizing the sum of the operation and disruption costs instead of using preventive load-shedding. In the model, it is also possible to directly target reliability indexes like the Loss of Load Probability or Expected Energy not Served. It is shown that increased reliability (in terms of the values of the indexes) can be obtained at a lower cost by targeting the indexes directly instead of resorting to reserve requirements. This is especially the case if flexible load-shedding routines are developed, making it possible to disconnect and reconnect the optimal amounts of load efficiently. The use of alternatives to fixed reserve requirements as a means to maintain system security does not solve the problem about how to ensure the availability of peaking capacity. However, in a situation with occasional capacity shortages, it gives the System Operator a tool to find the optimal balance between preventive load shedding and system security, which can result in significantly lower disruption costs in such cases. More research and development in this area is necessary to develop methods and tools that are suitable for large power systems. Ancillary Services Investment in peaking capacity is insufficient in restructured systems because expected revenues are too low or too uncertain. If generator revenues are increased, the situation improves. One way to obtain this is to create markets for ancillary services. In the thesis, a model is developed for a central-dispatch type of pool. In this model, markets for energy and three types of ancillary services are cleared simultaneously for 24 hours ahead. Market prices are such that volumes and prices are consistent with the market participants. self-dispatch decisions . i.e. given these prices, market participants would have chosen the same production of energy and ancillary services as the outcome of the optimization program. With this model, it is shown that markets for ancillary services increase generator revenues, but this effect is partly offset by lower energy prices. This shows that markets for ancillary services can contribute to improving the situation, but given the remaining uncertainty, this is hardly enough to solve the problem. Capacity Subscription Because consumers have preferences for two goods: electricity and reliability, they should ideally have the choice of purchasing the preferred amount of each of these. Traditionally this is not possible . reliability is a public good, produced or obtained by a central authority on behalf of all consumers. Technological progress is presently changing this. Capacity subscription is a method that allows consumers to choose their individual level of reliability, at the same time creating a true market for capacity. It is based on the concept of selfrationing. Consumers anticipate (for example on a seasonal basis) their need for capacity at the instant of system-wide peak demand. Based on this anticipation, they procure their desired level of capacity in a market, where generators offer their available capacity. Demand is limited to subscribed capacity by a fuse-like device that is activated when total demand exceeds total available generation. In this way, the capacity payment only influences the market when demand is close to installed capacity, and does not distort the energy price in other periods. Demand is not limited when there is ample capacity. Demand will never exceed supply, because it can be limited in an acceptable way when this situation occurs. Moreover, both consumers and suppliers can adapt to situations with scarce or ample capacity, and the price of capacity will reflect this situation. There is one problem with the method: as consumers do not reach their subscribed capacity simultaneously, there will be a capacity surplus at the instant the fuse-devices are activated. Two methods to solve this problem are analysed, and it is shown that the problem can be solved optimally by giving consumers who prefer this the opportunity to buy power in excess of their subscription on the spot market. Policy evaluation Six alternative policies to assess the peaking power problem are analysed based on the following criteria: - Static efficiency: the welfare-optimal match of consumption and supply - Dynamic efficiency: the ability to create incentives for innovation - Invisibility: with invisible strategies, each market actor pursues his or her own objectives without worrying about anyone else.s - Robustness: a robust policy is less sensitive to deviations from assumptions - Timeliness: the ability of a policy to be employed at the right time - Stakeholder equity: the degree to which all the involved parties are treated equitable - Corrigibility: the extent to which a policy can be corrected once it is employed - Acceptability: the degree to which the policy is acceptable to all parties - Simplicity: ceteris paribus simple strategies are preferable over more complicated strategies - Cost: the cost of implementing the policy - System security: the policy.s ability to obtain an acceptable level of system security The policies are, in short (an example is given in parentheses): - Capacity obligation: suppliers are obliged to keep sufficient capacity (PJM) - Fixed capacity payment: a fixed payment is offered for available capacity (Spain) - Dynamic capacity payment: capacity payment is based on the Loss of Load Probability (England and Wales) - Energy-only: no explicit payments or obligation (Scandinavia, California) - Proxy prices: very high administrative prices are used as a proxy to the Value of Lost Load when load shedding is necessary (Australia) - Capacity subscription: cf. the description above (not implemented) As could be expected, no single policy performs best on all criteria. The obligation and fixed payment methods do not perform well on market efficiency criteria, as essentially they are not market-based policies. The proxy prices policy is a reasonable policy on most criteria. It is easy, cheap and quick to implement. Because there is little experience with the method so far, there is some uncertainty with respect to if it is effective. One can anticipate that the threat of having to buy power at rationing prices will motivate market participants to avoid coming in a buying position in such cases, and that this will stimulate the adaptation of innovative solutions, especially on the demand side. The capacity subscription policy looks very promising on the issues of efficiency, robustness and system security. This is especially true for dynamic efficiency: consumers will weigh the cost of capacity against the cost of innovative load control devices, and if the price of capacity is high, a market for such technology will emerge. However, there is a considerable threshold prior to the introduction of capacity subscription, caused by the implementation costs and complexity. The conclusion on policies is thus that in an early stage after restructuring it may be appropriate to resort to the capacity obligation or payment method if the capacity balance is tight at the time of transition. For the medium-term, or if there is ample capacity initially, it is sensible to introduce proxy market prices to transfer the risk of a capacity deficit to market participants, with due attention being paid to the appropriate price level. Capacity subscription can be a long-term objective.

<p>The focus of this work has been on hybrid insulation in inhomogeneous electric fields under lightning impulse voltage stress. The principal idea behind hybrid insulation is the intentional use of surface charges to re-distribute the electric field within an insulation system. This allows a significant part of the electric stress to be transferred from the dielectric weaker gas to the dielectric stronger solid insulation thus increasing the total electric strength of the insulation system.</p><p>The concept has been theoretically and experimentally addressed by means of a hemispheric rod covered with a layer of solid insulation. Discharge activity and surface charge accumulation have been studied in an air gap by measuring the voltage and discharge current and recording the discharge activity using a high-speed digital camera. New methods have been introduced and evaluated for the evaluation of surface charge measurements.</p><p>The experiments found that the increase in positive inception voltage was considerable compared to uncovered rods. This increase varied from 35% up to 100% depending on the electrode distance. The increase in breakdown strength is higher than the increase in inception voltage and dependent on the covered length of the rod. During the application of a lightning impulse, the discharge activity spreads upwards along the rod and out into the air gap. Positive discharges form numerous branches and bridge the air gap in most cases. Negative discharges are more diffuse, less light intensive and only form a few branches around the tip of the rod where the electric field is the strongest. Discharge activity along the insulating surface has been observed where the background field is lower than the critical electric field strength. Visible discharge activity is observed where the background field is higher than 2.3 kV/mm and 2.5 kV/mm for positive and negative impulses respectively.</p><p>During the application of lightning impulses, discharge activity starts in the air gap around the tip where the electric field is highest and spreads upwards along the rod. As expected, negative charges accumulate on the surface in the case of positive impulse voltage and vice versa. However, after more powerful discharges during negative impulse voltage application, surface charges of both polarities have been observed.</p><p>Accumulated surface charges decay exponentially with a time constant τ varying from micro-seconds to hours depending on the material properties of the solid insulation. The dominating relaxation mechanism is found to be conduction through the solid insulation.</p><p>Improved methods to calculate surface charges based on probe response for a 2D axial symmetric case have been developed and evaluated. The method that is best suited for this purpose is the λ-method with truncated singular value decomposition (TSVD) as regularization.</p><p>Surface charge calculations show that the accumulated surface charges for the used configuration typically have a maximum value of 0.6 to 1.5 µC/m² and 0.4 to 1 µC/m² after positive and negative impulses respectively. The surface charge density in the areas with the highest discharge activity is relatively uniform. Further upwards along the rod, the surface charge density is reduced relatively fast towards zero, and in some cases, it changes polarity before approaching zero.</p>

<p>Klimatförändringar börjar allt mer få en viktig roll i allas vardag och för energibranschen har arbetet med att minska miljöpåverkan bara börjat. Branschen har sedan en tid tillbaka premierat fjärrvärme som bra miljöval för uppvärmningskälla för bostäder och lokaler. Faktum kvarstår dock att beroende på hur fjärrvärmesystemet ser ut så påverkar näten miljön olika. I denna rapport behandlas det lokala energibolaget Halmstads Energi och Miljös fjärrvärmesystem genom en optimering av systemkostnaden. Utifrån optimeringen studeras sedan skuggpriser, drift och miljöpåverkan för systemet. Studien behandlar även de stora fördelarna med att energibolaget samarbetar med en eventuellt kommande energikrävande industrier, i detta fall en etanolfabrik. I och med samarbetet bildas ett energikombinat där fjärrvärme, el och etanol tillverkas.</p><p>För analysen används ett energisystemperspektiv som får större geografiska gränser än bara Halmstad. Undersökningen av systemet görs med hjälp av datorprogrammet MODEST som är ett energioptimeringsprogram som utvecklats på Linköpings Tekniska högskola. Modellen av Halmstads fjärrvärmenät baseras och valideras mot driftsäsongen 2005 och har visat sig stämma med verkligheten bra.</p><p>Resultatet visar att Halmstad Energi och Miljö planerade effekthöjningar används fullt ut men att det nätet kommer få stora effekttoppar inom en snar framtid. Energikombinatet som analyseras visar sig både ha ekonomiska som miljöfördelar för både energibolaget och en etanolfabrik. Spillvärmen som kan utvinnas kan även den minska användningen av topplastanläggningarna i fjärrvärmenätet.</p>

<p>Examensarbetet har utförts på uppdrag av NEA Gruppen och är en elkvalitetsanalys av VBG Groups maskinhall. Målet med analysen var att uppvisa elkvaliteten i maskinhallen.</p><p>Perfekt elkvalitet kan definieras som total frånvaro av elektriska störningar. Av elektriska störningar är det framförallt spänningsstörningar, såsom kortvariga spänningsvariationer, spänningsosymmetrier, spänningstransienter och likspänningskomponnenter, som orsakar mest besvär för elnät och anslutna laster. Även övertoner, som kan delas i spännings- och strömövertoner, påverkar elsystem på ett negativt sätt.</p><p>Analysen visar att maskinhallens spänning är stabil. Detta var väntat då kortslutningseffekten är hög jämfört med anläggningens storlek. Det matande nätet kan alltså anses starkt.</p><p>Maskinhallens laster alstrar strömövertoner av framförallt ordningstalen 5 och 7 men eftersom det matande nätet är starkt ger dessa inte upphov till några spänningsövertoner som ligger utanför rekommenderade gränser.</p><p>I maskinhallens ena inmatningspunkt, T1A15, finns ett kondensatorbatteri anslutet för reaktiv effektkompensering. Vid den andra inmatningspunkten, transformatorstation T3, finns idag ingen kompenseringsutrustning. Behovet är inte heller stort då belastningsgraden av T3 idag är under 10%. Man kan dock se att den reaktiva effekten redan nu är lika stor som den aktiva vilket medför att effektfaktorn är ca 0,7 och inom en nära framtid kommer fler laster att anslutas till T3 vilket innebär att ett kondensatorbatteri kan vara en lönsam investering.</p><p>Maskinhallens belysning alstrar strömövertoner av framförallt ordningstal tre. Övertoner av detta ordningstal har egenskapen att de ger upphov till strömmar i neutralledaren, i värsta fall så stora att neutralledaren blir överbelastad. Någon risk för överbelastning av neutralledaren för maskinhallens belysningsgrupp finns dock inte.</p><p>Totalt sett är anläggningens elkvalitet god och inga akuta åtgärder behöver vidtas.</p>

<p>För att öka skyddet mot elektriska fält i processnätet på Stora Enso Skoghalls bruk utreds det i denna rapport om det går att direktjorda processnätet som i dagens läge endast är skyddsjordat. Eftersom det tidigare endast funnits skyddsjord vill företaget veta om kabeldimensioneringen är tillräcklig så att de skydd man har mot kortslutningsströmmar även fungerar i ett direktjordat nät. I ett direktjordat nät blir den minsta kortslutningsströmmen cirka gånger mindre än icke direktjordat nät då kortslutning kan ske mellan fas och nolla (fasspänning). Nollan finns inte i ett icke direktjordat nät och kablarna är kan alltså vara för långa eller för klena så att en fasspänning inte klarar att driva tillräckligt stor ström vid kortslutning genom kabelns impedans förr att skydden skall lösa ut. Eftersom en nydragning av alla de kilometervis utlagda kablarna skulle bli en så ofantligt kostnad och att tiden för stoppet av processen skulle bli för lång är detta inte ett alternativ. Den här utredningen kommer att visa maximala kabellängden mellan de olika ställverken och motorerna i det befintliga nätet för att man skall kunna direktjorda det.</p> / <p>To increase the protection against electrical fields in the distribution net on Stora Enso’s mill in Skoghall it will be investigated if it’s possible to use direct earth instead of only protective earth as of today. Because the net only has protective earth the company wants to know if the dimensions of the cables are enough to meet the lesser shortcut voltage in a net with direct earth. The smallest shortcut current when using direct earth occurs between one phase and the zero and will be aproximately times less than when using non direct earth where there is not a zero and the shortcut can onlyu occur between two phases. This means that when building a non direct eart net you can use longer or thinner cables with more resistance than you could using direct earth. New cables are not an alternative when the cost would be to great and the downtime of the machines would be too long. This inquiry will show the maximum cabel length from the different protections to the different engines can be if you want to use direct earth and be sure that the fuses will burn when an error occurs.</p>

<p>Harmonics are a well-known problem that has to be dealt with in the design of thegenerator. Internationally accepted standards limits the amount of harmonics allowedin the no-load voltage. These limits can be difficult to fulfill with integral slot winding,where the number of slots per pole and phase is an integer. The presence of thedamper winding often makes the problem with harmonics even worse and harmonicswith frequencies of order 6q±1 arise with significant amplitude. How the damperwinding is designed affect the content of harmonics in the no-load voltage and the aimwith these … has been to investigate in which extent design of the damper windingaffects the contents of harmonics.Simulations with the 2-D finite element method have showed that if the damper barsis centered in the pole shoe, the amplitude of the harmonics of order 6q±1dependsboth on the ratio between the stator slot pitch and damper bars slot pitch and if thedamper bars are connected between the poles or not.If the damper bars is displaced with ¼ stator slot pitch alternately, the amplitude ofthe harmonics of order 6q±1 is reduced and the influence of the ratio between thestator slot pitch and the damper bars slot pitch will vanish. To minimize the loss inthe damper bars the distance between the damper bars should then be equal thedistance between the stator slots.</p>

The focus of this work has been on hybrid insulation in inhomogeneous electric fields under lightning impulse voltage stress. The principal idea behind hybrid insulation is the intentional use of surface charges to re-distribute the electric field within an insulation system. This allows a significant part of the electric stress to be transferred from the dielectric weaker gas to the dielectric stronger solid insulation thus increasing the total electric strength of the insulation system. The concept has been theoretically and experimentally addressed by means of a hemispheric rod covered with a layer of solid insulation. Discharge activity and surface charge accumulation have been studied in an air gap by measuring the voltage and discharge current and recording the discharge activity using a high-speed digital camera. New methods have been introduced and evaluated for the evaluation of surface charge measurements. The experiments found that the increase in positive inception voltage was considerable compared to uncovered rods. This increase varied from 35% up to 100% depending on the electrode distance. The increase in breakdown strength is higher than the increase in inception voltage and dependent on the covered length of the rod. During the application of a lightning impulse, the discharge activity spreads upwards along the rod and out into the air gap. Positive discharges form numerous branches and bridge the air gap in most cases. Negative discharges are more diffuse, less light intensive and only form a few branches around the tip of the rod where the electric field is the strongest. Discharge activity along the insulating surface has been observed where the background field is lower than the critical electric field strength. Visible discharge activity is observed where the background field is higher than 2.3 kV/mm and 2.5 kV/mm for positive and negative impulses respectively. During the application of lightning impulses, discharge activity starts in the air gap around the tip where the electric field is highest and spreads upwards along the rod. As expected, negative charges accumulate on the surface in the case of positive impulse voltage and vice versa. However, after more powerful discharges during negative impulse voltage application, surface charges of both polarities have been observed. Accumulated surface charges decay exponentially with a time constant τ varying from micro-seconds to hours depending on the material properties of the solid insulation. The dominating relaxation mechanism is found to be conduction through the solid insulation. Improved methods to calculate surface charges based on probe response for a 2D axial symmetric case have been developed and evaluated. The method that is best suited for this purpose is the λ-method with truncated singular value decomposition (TSVD) as regularization. Surface charge calculations show that the accumulated surface charges for the used configuration typically have a maximum value of 0.6 to 1.5 µC/m² and 0.4 to 1 µC/m² after positive and negative impulses respectively. The surface charge density in the areas with the highest discharge activity is relatively uniform. Further upwards along the rod, the surface charge density is reduced relatively fast towards zero, and in some cases, it changes polarity before approaching zero.

The introduction of large amounts of wind power into power systems will increase the production uncertainties due to unforeseen wind power production variations. This will have a significant impact on the required balance management quantities. The most suitable power source to balance fast production or consumption variations is hydropower because of its flexibility and low operational costs. This thesis addresses the problem of trading of electricity on the daily marketfrom a hydropower producer perspective in a system with large amounts of wind power. The overall aim is to present models that can be used in the trading decision process. This thesis describes models within three different areas:1. Modeling of the demand for balancing power by using deterministic andstochastic models. The stochastic models are based on stochastic differentialequations.2. Modeling of prices on the day-ahead and real-time markets using deterministic and stochastic models. The stochastic models are based on time series modeling.3. Short-term hydropower scheduling of trading decisions. These problems areformulated as stochastic optimization problems where the market prices arerandom variables. The first two can be used to simulate the impact of wind power on various market prices, while the third simulates how the hydropower producer responds to market prices. Thereby, the thesis presents the necessary models for short-term scheduling of hydropower for a future system with significant amounts of wind power. This thesis concludes that the proposed price models are sufficient to reflect the relevant price properties, and that the proposed short-term hydropower scheduling models can be used to simulate the actions taken by the hydropower producer in a system with significant amounts of wind power. This is also supported by the case studies in the appended publications. / QC 20100804

Följande rapport beskriver ett projektarbete i att ersätta en automatisk spännings regulator (AVR) till en gammal ASEA dieselgeneratoranläggning. Generatorn är installerad på M/S Calmare Nyckel som tillhör Sjöfartshögskolan i Kalmar. Generatoranläggningen används enbart i utbildningssyfte. Den AVR som ska ersättas är en ASEA UTWH310. Det är ett väldigt gammal anläggning och vi uppskattar att den härstammar från 60-talet. Problemet med den gamla regulatorn är att när systemet har körts en stund så är det inte längre möjligt att reglera den reaktiva effekten. Vi blev tillfrågade att ersätta det gamla systemet, därför har vi inte gjort något försök att laga det. Regulatorn matar ström till en liten DC generator, mataren, som är ansluten till den större AC generatorn med remdrift. Mataren magnetiserar sedan rotorn i AC generatorn. För att få klarhet i hur systemet fungerade så gjorde vi några testkörningar. Vi tog reda på nödvändiga parametrar för att kunna ersätta den gamla anläggningen. Eftersom vi inte hade någon tidigare erfarenhet av den här typen av projekt, så hade vi lite problem att hitta en leverantör av den nya AVR utrustningen. Som tur var kom vi i kontakt med Subtron AB, ett litet företag från Enköping. De var mycket hjälpsamma, och de hade både kunskapen och utrustningen som vi behövde. Vi beslutade oss för att beställa Leroy-Somers R 448 AVR. Det är en enkel AVR men fullt kapabel att utföra det vi efterfrågar. Vi beställde också en del kringutrustning till installationen. Efter att ha testkört den nya utrustningen och kommit fram till att den fungerade utmärkt så utfördes installationen sedan på några dagar. / This following report describes a project in replacing the Automatic Voltage Regulator (AVR) in an old ASEA diesel generator system. The generator is installed on M/S Calmare Nyckel which belongs to Kalmar Maritime Academy. The Generator system is solely used for educational purposes. The AVR that is being replaced is an ASEA UTWH310. It is a very old system and we assume its from some where around 1960. The problem with the old AVR is that when the system has been running for a while there is no longer possible to control the reactive power. We were asked to replace the old system, so not much effort has been put on trying to repair it. The AVR feeds current to a small DC generator, feeder, witch is connected by a strap drive to the larger AC generator. The feeder then excites the rotor in the AC generator. To find out how the system actually worked we made some test runs. We measured necessary variables to be able to replace the old system. Because we had no formerly experience in this type of project, we had some troubles in finding a supplier of AVR equipment. Luckily we came in contact with a small company called Subtron AB from Enköping. They were very helpful and had both the equipments and the knowledge that we needed for our project. We decided to order Leroy-Somers R 448 AVR. It is a simple but fully capable AVR to preform what we asked for. We also ordered some auxiliary equipment for the installation. After a test run with the new equipment, we found out that it worked very well. The installation process was then made in a few days.

Hydroware Elevation Technology AB sells control and regulation equipment for hydraulic elevators. The company now wants to investigate the possibility of changing their present softstarters to frequency inverters to supply power to their pump engines. They also want to investigate the possibility of future use in so called ”intelligent” houses. The purpose of this report is to investigate these possibilities.