{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,1,23]],"date-time":"2026-01-23T20:10:59Z","timestamp":1769199059736,"version":"3.49.0"},"reference-count":20,"publisher":"MDPI AG","issue":"17","license":[{"start":{"date-parts":[[2020,9,1]],"date-time":"2020-09-01T00:00:00Z","timestamp":1598918400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Energies"],"abstract":"<jats:p>The use of pumps working as turbines (PATs) is a sustainable technical measure that contributes to the improvement of energy efficiency in water systems. However, its performance analysis in off-grid recovery systems is a complex task that must consider both hydraulic (PAT) and electrical machines (typically a self-excited induction generator-SEIG). Aside from several kinds of research that analyze the PAT-SEIG behavior under steady-state constant hydraulic and electrical conditions, this research focuses on the analysis of PAT-SEIG transient regimes, by analyzing their variation when a sudden change occurs in the hydraulic or electrical components. Analytical models were developed to represent the operation of SEIG, PAT, and the PAT-SEIG coupled system. Hydraulic and electromechanical experimental tests validated these models. An excellent fit was obtained when analytical and experimental values were compared. With these models, the impact on the operation of the PAT-SEIG system was examined when sudden change occurred in the excitation capacitances, resistive loads, or recovered head. With a sudden increase of resistive load, the hydraulic power and SEIG stator current remain almost constant. However, there is an increase of SEIG reactive power, decreasing the PAT-SEIG efficiency. Also, with a sudden increase of SEIG capacitors or PAT hydraulic head, the SEIG stator current increases once and not again, while PAT-SEIG efficiency decreases, but the induction generator can be overloaded. The development of this research is key to the advancement of future models which can analyze the coupling of micro-hydropower solutions.<\/jats:p>","DOI":"10.3390\/en13174521","type":"journal-article","created":{"date-parts":[[2020,9,1]],"date-time":"2020-09-01T08:53:43Z","timestamp":1598950423000},"page":"4521","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":11,"title":["Electro-Hydraulic Transient Regimes in Isolated Pumps Working as Turbines with Self-Excited Induction Generators"],"prefix":"10.3390","volume":"13","author":[{"given":"Filipe C.","family":"Madeira","sequence":"first","affiliation":[{"name":"Instituto Superior T\u00e9cnico, Universidade de Lisboa, 1049-001 Lisboa, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9674-5490","authenticated-orcid":false,"given":"Jo\u00e3o F. P.","family":"Fernandes","sequence":"additional","affiliation":[{"name":"IDMEC, Instituto Superior T\u00e9cnico, Universidade de Lisboa, 1049-001 Lisboa, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8316-7778","authenticated-orcid":false,"given":"Modesto","family":"P\u00e9rez-S\u00e1nchez","sequence":"additional","affiliation":[{"name":"Hydraulic and Environmental Engineering Department, Universitat Polit\u00e8cnica de Val\u00e8ncia, 46022 Valencia, Spain"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7043-3683","authenticated-orcid":false,"given":"P. Amparo","family":"L\u00f3pez-Jim\u00e9nez","sequence":"additional","affiliation":[{"name":"Hydraulic and Environmental Engineering Department, Universitat Polit\u00e8cnica de Val\u00e8ncia, 46022 Valencia, Spain"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9028-9711","authenticated-orcid":false,"given":"Helena M.","family":"Ramos","sequence":"additional","affiliation":[{"name":"Civil Engineering, Architecture and Georesources Department, CERIS, Instituto Superior T\u00e9cnico, Universidade de Lisboa, 1049-001 Lisboa, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7072-5184","authenticated-orcid":false,"given":"P. J.","family":"Costa Branco","sequence":"additional","affiliation":[{"name":"IDMEC, Instituto Superior T\u00e9cnico, Universidade de Lisboa, 1049-001 Lisboa, Portugal"}]}],"member":"1968","published-online":{"date-parts":[[2020,9,1]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Postacchini, M., Darvini, G., Finizio, F., Pelagalli, L., Soldini, L., and di Giuseppe, E. (2020). Hydropower generation through pump as turbine: Experimental study and potential application to small-scale WDN. Water, 12.","DOI":"10.3390\/w12040958"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"302","DOI":"10.1016\/j.apenergy.2017.10.039","article-title":"Electrical behaviour of the pump working as turbine in off grid operation","volume":"208","author":"Capelo","year":"2017","journal-title":"Appl. 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Energy"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"725","DOI":"10.1016\/j.renene.2020.03.142","article-title":"Dynamic mode decomposition and reconstruction of tip leakage vortex in a mixed flow pump as turbine at pump mode","volume":"155","author":"Han","year":"2020","journal-title":"Renew. Energy"},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"234","DOI":"10.1016\/j.renene.2017.09.060","article-title":"PATs selection towards sustainability in irrigation networks: Simulated annealing as a water management tool","volume":"116","author":"Ramos","year":"2018","journal-title":"Renew. Energy"},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"04019066","DOI":"10.1061\/(ASCE)WR.1943-5452.0001152","article-title":"Maximizing hydropower generation in gravity water distribution networks: Determining the optimal location and number of pumps as turbines","volume":"146","author":"Nabola","year":"2020","journal-title":"J. Water Resour. Plan. 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Pumps as Turbines, Fundamentals and Applications, Springer.","DOI":"10.1007\/978-3-319-67507-7"},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"e1202","DOI":"10.5424\/sjar\/2017151-10144","article-title":"Calibrating a flow model in an irrigation network: Case study in Alicante, Spain","volume":"15","author":"Ramos","year":"2017","journal-title":"Span. J. Agric. Res."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"885","DOI":"10.13031\/2013.23153","article-title":"Model evaluation guidelines for systematic quantification of accuracy in watershed simulations","volume":"50","author":"Moriasi","year":"2007","journal-title":"Trans. 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