Avbördning via turbinerna : En fallstudie av ett litet vattenkraftverk och ett högt flöde

In 1990 Flödeskommittén released new guidelines which redefined the method used to determine design flows. The method, combined with more complete measurements of flow variations, has resulted in higher design flows which in turn call for increases in the discharge capacity of hydropower plants. Thi...

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Main Author: Gidstedt, Mikael
Format: Others
Language:Swedish
Published: Uppsala universitet, Elektricitetslära 2015
Subjects:
Online Access:http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-260578
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spelling ndltd-UPSALLA1-oai-DiVA.org-uu-2605782015-08-22T05:20:06ZAvbördning via turbinerna : En fallstudie av ett litet vattenkraftverk och ett högt flödesweGidstedt, MikaelUppsala universitet, Elektricitetslära2015Hydropowerdam safetydischarge capacitydump loadVattenkraftdammsäkerhetavbördningdumplastIn 1990 Flödeskommittén released new guidelines which redefined the method used to determine design flows. The method, combined with more complete measurements of flow variations, has resulted in higher design flows which in turn call for increases in the discharge capacity of hydropower plants. This work is still in progress. Since many Swedish hydropower stations were constructed in the 1950's and 60's they require modernization. Today Statkraft owns and operates 55 hydropower stations in Sweden several of which have a discharge capacity below the design flow. For this reason, the dam safety of these hydropower stations is reduced. According to current guidelines the turbine flow is not added to the discharge capacity since the availability of the electrical grid is not guaranteed during extreme flows. When the electric grid is unavailable the generator has no load and cannot produce an electric torque. Without the electric torque the turbine accelerates which may result in equipment failure. This thesis considers the introduction of an alternative local load where the generator power can be dumped as heat, hence termed dump load. The dump load has the potential to increase the discharge capacity by adding the turbine flow. However, operation of the dump load requires the availability of the generator and turbine, making the discharge capacity dependent on the status of the plant. In turn, achieving a sufficient discharge capacity is of primary concern to dam operators since it determines dam safety. Consequently, this thesis evaluates the effects on dam safety when utilizing a local load to increase the discharge capacity. Three different designs were evaluated; a medium to high voltage electrode water boiler, electrodes submerged in the river and a low voltage electric water boiler. The evaluation shows that all three designs are feasible and can be used to increase the discharge capacity provided the generator and turbine have high availability. The complexity and number of components constituting the dump load should be minimized to reduce the risk of malfunctions and redundancy should be introduced for key components when feasible. The dump load power should be controlled using voltage regulation but further work is required to determine the specifics of this governor. The results also show that the cost of the dump load is a fraction of the cost of a new spillway. However, the topic is controversial and the dump load requires practical testing in order to evaluate operational reliability. Student thesisinfo:eu-repo/semantics/bachelorThesistexthttp://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-260578UPTEC ES, 1650-8300 ; 15037application/pdfinfo:eu-repo/semantics/openAccess
collection NDLTD
language Swedish
format Others
sources NDLTD
topic Hydropower
dam safety
discharge capacity
dump load
Vattenkraft
dammsäkerhet
avbördning
dumplast
spellingShingle Hydropower
dam safety
discharge capacity
dump load
Vattenkraft
dammsäkerhet
avbördning
dumplast
Gidstedt, Mikael
Avbördning via turbinerna : En fallstudie av ett litet vattenkraftverk och ett högt flöde
description In 1990 Flödeskommittén released new guidelines which redefined the method used to determine design flows. The method, combined with more complete measurements of flow variations, has resulted in higher design flows which in turn call for increases in the discharge capacity of hydropower plants. This work is still in progress. Since many Swedish hydropower stations were constructed in the 1950's and 60's they require modernization. Today Statkraft owns and operates 55 hydropower stations in Sweden several of which have a discharge capacity below the design flow. For this reason, the dam safety of these hydropower stations is reduced. According to current guidelines the turbine flow is not added to the discharge capacity since the availability of the electrical grid is not guaranteed during extreme flows. When the electric grid is unavailable the generator has no load and cannot produce an electric torque. Without the electric torque the turbine accelerates which may result in equipment failure. This thesis considers the introduction of an alternative local load where the generator power can be dumped as heat, hence termed dump load. The dump load has the potential to increase the discharge capacity by adding the turbine flow. However, operation of the dump load requires the availability of the generator and turbine, making the discharge capacity dependent on the status of the plant. In turn, achieving a sufficient discharge capacity is of primary concern to dam operators since it determines dam safety. Consequently, this thesis evaluates the effects on dam safety when utilizing a local load to increase the discharge capacity. Three different designs were evaluated; a medium to high voltage electrode water boiler, electrodes submerged in the river and a low voltage electric water boiler. The evaluation shows that all three designs are feasible and can be used to increase the discharge capacity provided the generator and turbine have high availability. The complexity and number of components constituting the dump load should be minimized to reduce the risk of malfunctions and redundancy should be introduced for key components when feasible. The dump load power should be controlled using voltage regulation but further work is required to determine the specifics of this governor. The results also show that the cost of the dump load is a fraction of the cost of a new spillway. However, the topic is controversial and the dump load requires practical testing in order to evaluate operational reliability.
author Gidstedt, Mikael
author_facet Gidstedt, Mikael
author_sort Gidstedt, Mikael
title Avbördning via turbinerna : En fallstudie av ett litet vattenkraftverk och ett högt flöde
title_short Avbördning via turbinerna : En fallstudie av ett litet vattenkraftverk och ett högt flöde
title_full Avbördning via turbinerna : En fallstudie av ett litet vattenkraftverk och ett högt flöde
title_fullStr Avbördning via turbinerna : En fallstudie av ett litet vattenkraftverk och ett högt flöde
title_full_unstemmed Avbördning via turbinerna : En fallstudie av ett litet vattenkraftverk och ett högt flöde
title_sort avbördning via turbinerna : en fallstudie av ett litet vattenkraftverk och ett högt flöde
publisher Uppsala universitet, Elektricitetslära
publishDate 2015
url http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-260578
work_keys_str_mv AT gidstedtmikael avbordningviaturbinernaenfallstudieavettlitetvattenkraftverkochetthogtflode
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