Publicação
Superconductivity for energy applications Impact of Unbalanced Loads on AC Losses of Inductive HTS Fault Current Limiters
| Resumo: | Superconducting fault current limiters (SFCLs) are recognized as one of the large-scale applications of high-temperature superconducting (HTS) materials with the highest potential to reach the commercial market. SFCLs can be integrated into multiple locations in electrical grids, contributing to the electrification of the energy system and, thus, to the Energy Transition. Besides limiting the levels of short-circuit currents, SFCLs allow, e.g., increasing the penetration of renewable generation while keeping the ratings of existing protections and postponing investments by utilities. Several topologies of SFCLs have been developed, with the two most mature being the resistive and inductive, with the latter existing in two different types named saturated cores and transformer-type SFCL. The transformer-type SFCL is the focus in this dissertation and is comprised of a three-phase transformer with three short-circuited HTS secondary windings as its secondaries. By inducing voltage in these superconducting secondaries, AC losses are generated, which should be estimated before creating proper cryogenic solutions for these SFCLs. Another important aspect of the SFCL power loss behaviour when connected to the distribution grid is the effect of unbalanced currents on this device, which also may increase AC losses. This dissertation aimed to study theAC loss behaviour of such devices in environments with distinct load balance via extensive experimental measurements as an effort to learn how to improve the SFCL, especially its cryostat design. This objectivewas accomplished by creating three HTS windings from HTS tapes using methods for superconductor jointing and build instrumentation which can effectively measure the current and electromotive force of these secondaries while operating as part of a Transformer-type SFCL. The results obtained in this work characterize these AC losses and demonstrate that there is a relevant effect on the losses in the secondaries due to unbalanced loads. |
|---|---|
| Autores principais: | Durão, Diogo Miguel Dias |
| Assunto: | Transformer-type SFCL AC losses HTS winding Unbalanced loads Threephase Cryostats |
| Ano: | 2023 |
| País: | Portugal |
| Tipo de documento: | dissertação de mestrado |
| Tipo de acesso: | acesso aberto |
| Instituição associada: | Universidade Nova de Lisboa |
| Idioma: | inglês |
| Origem: | Repositório Institucional da UNL |
| Resumo: | Superconducting fault current limiters (SFCLs) are recognized as one of the large-scale applications of high-temperature superconducting (HTS) materials with the highest potential to reach the commercial market. SFCLs can be integrated into multiple locations in electrical grids, contributing to the electrification of the energy system and, thus, to the Energy Transition. Besides limiting the levels of short-circuit currents, SFCLs allow, e.g., increasing the penetration of renewable generation while keeping the ratings of existing protections and postponing investments by utilities. Several topologies of SFCLs have been developed, with the two most mature being the resistive and inductive, with the latter existing in two different types named saturated cores and transformer-type SFCL. The transformer-type SFCL is the focus in this dissertation and is comprised of a three-phase transformer with three short-circuited HTS secondary windings as its secondaries. By inducing voltage in these superconducting secondaries, AC losses are generated, which should be estimated before creating proper cryogenic solutions for these SFCLs. Another important aspect of the SFCL power loss behaviour when connected to the distribution grid is the effect of unbalanced currents on this device, which also may increase AC losses. This dissertation aimed to study theAC loss behaviour of such devices in environments with distinct load balance via extensive experimental measurements as an effort to learn how to improve the SFCL, especially its cryostat design. This objectivewas accomplished by creating three HTS windings from HTS tapes using methods for superconductor jointing and build instrumentation which can effectively measure the current and electromotive force of these secondaries while operating as part of a Transformer-type SFCL. The results obtained in this work characterize these AC losses and demonstrate that there is a relevant effect on the losses in the secondaries due to unbalanced loads. |
|---|