{"id":{"repo_id":"auckland-ms","oai_identifier":"oai:researchspace.auckland.ac.nz:2292/50984"},"canonical_url":"https://search.dev.ndltd.org/etd/auckland-ms/oai:researchspace.auckland.ac.nz:2292/50984","repository":{"repo_id":"auckland-ms","name":"University of Auckland","base_url":"https://researchspace.auckland.ac.nz/server/oai/request"},"display":{"title":"Induction generators in mini and micro hydro applications as a low cost alternative","abstract":"This study develops low cost techniques for mini and micro hydro power generation with the chief concern of investigating induction generators as a viable alternative. A method of reconfiguring the static excitation of a self-excited induction generator is studied to supply a single-phase or an unbalanced three-phase load using a standard three-phase machine. This scheme is particularly suitable in the micro range where the loads are generally single-phase or unbalanced three-phase type. A scheme of reconfiguring the existing static excitation is suggested which results in a balanced condition at a partial rating, and as a consequence considerable improvement in the de-rating factor is achieved. Alternatively extra reactive components are required to balance a single-phase load of the full three-phase rating. A generalized condition for balancing is developed and analytical relationships are derived for de-rating an induction motor. However, such analytical treatments are difficult for induction generators therefore a comprehensive method of modelling a three-phase induction generator under unbalanced excitation and loading is presented. The de-rating and voltage regulation characteristics computed from this model are checked against test results on a laboratory machine. In an attempt to make a microhydro system economical, such unconventional equipment as a reverse mode centrifugal pump and an Electronic Load Governor are used. The economics of using the unconventional equipment are compared to the conventional situation. A full fledged microhydro test rig is developed with unconventional equipment, and the design and selection method is discussed. In order to add such features as improved reliability, load factor and economic scheduling, parallel operation with a minigrid system is considered. The synchronizing transients observed on the test rig are of an unusual nature while the steady state performance is satisfactory. A simulation study is conducted to identify the cause of the unusual nature of synchronizing transients and to suggest measures to avoid them. Both electrical and hydraulic systems are represented. A new concept for modelling the electrical system is presented and the hydraulic system model is deduced from established models. However, all parameters of the hydraulic model are not known. An identification study is conducted on the input-output characteristics of the model to determine those parameters. The study also reveals the cause of the unusual nature of the synchronizing transients and possible corrective actions are suggested. Further investigations are carried out to establish the use of induction generators in minihydro systems as a viable alternative. It is found that the economic viability depends on meeting the excitation requirements by other synchronous generators and as such they may be operated in parallel with a power system network where there are other synchronous generators. Consequently the operation of the minihydro system is studied in conjunction with other thermal and hydro power stations. A real-time simulation method is used for reasons of accuracy, indepth comprehension and easy monitoring of variables. In this real-time simulation study sub-systems like the induction generator and turbogenerator are replaced by their real physical scaled down models while others are simulated on microcomputers controlling these generators. The chief purpose of the real-time simulation model is to study the behaviour of a minihydro power station using an induction generator in an interconnected system. However, the presence of a combination of thermal and hydro power station creates a problem of hydrothermal coordination. The role of an automatic generation controller is adequately represented and a controller is developed for the minihydro power station. Successful implementation of the hydrothermal coordination then establishes the credibility of the operation of a minihydro station in this situation.","abstract_html":"This study develops low cost techniques for mini and micro hydro power generation with the chief concern of investigating induction generators as a viable alternative. A method of reconfiguring the static excitation of a self-excited induction generator is studied to supply a single-phase or an unbalanced three-phase load using a standard three-phase machine. This scheme is particularly suitable in the micro range where the loads are generally single-phase or unbalanced three-phase type. A scheme of reconfiguring the existing static excitation is suggested which results in a balanced condition at a partial rating, and as a consequence considerable improvement in the de-rating factor is achieved. Alternatively extra reactive components are required to balance a single-phase load of the full three-phase rating. A generalized condition for balancing is developed and analytical relationships are derived for de-rating an induction motor. However, such analytical treatments are difficult for induction generators therefore a comprehensive method of modelling a three-phase induction generator under unbalanced excitation and loading is presented. The de-rating and voltage regulation characteristics computed from this model are checked against test results on a laboratory machine. In an attempt to make a microhydro system economical, such unconventional equipment as a reverse mode centrifugal pump and an Electronic Load Governor are used. The economics of using the unconventional equipment are compared to the conventional situation. A full fledged microhydro test rig is developed with unconventional equipment, and the design and selection method is discussed. In order to add such features as improved reliability, load factor and economic scheduling, parallel operation with a minigrid system is considered. The synchronizing transients observed on the test rig are of an unusual nature while the steady state performance is satisfactory. A simulation study is conducted to identify the cause of the unusual nature of synchronizing transients and to suggest measures to avoid them. Both electrical and hydraulic systems are represented. A new concept for modelling the electrical system is presented and the hydraulic system model is deduced from established models. However, all parameters of the hydraulic model are not known. An identification study is conducted on the input-output characteristics of the model to determine those parameters. The study also reveals the cause of the unusual nature of the synchronizing transients and possible corrective actions are suggested. Further investigations are carried out to establish the use of induction generators in minihydro systems as a viable alternative. It is found that the economic viability depends on meeting the excitation requirements by other synchronous generators and as such they may be operated in parallel with a power system network where there are other synchronous generators. Consequently the operation of the minihydro system is studied in conjunction with other thermal and hydro power stations. A real-time simulation method is used for reasons of accuracy, indepth comprehension and easy monitoring of variables. In this real-time simulation study sub-systems like the induction generator and turbogenerator are replaced by their real physical scaled down models while others are simulated on microcomputers controlling these generators. The chief purpose of the real-time simulation model is to study the behaviour of a minihydro power station using an induction generator in an interconnected system. However, the presence of a combination of thermal and hydro power station creates a problem of hydrothermal coordination. The role of an automatic generation controller is adequately represented and a controller is developed for the minihydro power station. Successful implementation of the hydrothermal coordination then establishes the credibility of the operation of a minihydro station in this situation.","abstract_has_math":false,"creators":["Bhattacharya, Jayant Lal"],"institution":"ResearchSpace@Auckland","degree_name":"PhD","degree_level":"Doctoral","degree_discipline":"Electrical and Electronic Engineering","degree_department":null,"school":null,"contributors":[],"advisors":["Woodward, J.L.","Boys, J.T."],"committee_chairs":[],"committee_members":[],"year":1988,"date_issued":"1988","date_published":"1988","updated_at":"2026-07-24T01:07:07Z","subjects":[],"languages":[],"rights":["Items in ResearchSpace are protected by copyright, with all rights reserved, unless otherwise indicated.","Restricted Item. Full text is available to authenticated members of The University of Auckland only."],"rights_urls":["https://researchspace.auckland.ac.nz/docs/uoa-docs/rights.htm"],"identifier_entries":[]},"links":{"outbound_url":"https://hdl.handle.net/2292/50984","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.advisor","label":"Advisor","values":["Woodward, J.L.","Boys, J.T."]},{"key":"dc:creator","label":"Author","values":["Bhattacharya, Jayant Lal"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2020-06-02T04:32:04Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2020-06-02T04:32:04Z"]},{"key":"dc:date.issued","label":"Date","values":["1988"]},{"key":"dc:publisher","label":"Institution","values":["ResearchSpace@Auckland"]},{"key":"dc:relation.isreferencedby","label":"Dc Relation Isreferencedby","values":["UoA9974688414002091"]},{"key":"dc:type","label":"Dc Type","values":["Thesis"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Electrical and Electronic Engineering"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Doctoral"]},{"key":"thesis:degree_name","label":"Degree Name","values":["PhD"]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["The University of Auckland"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:rights","label":"Dc Rights","values":["Items in ResearchSpace are protected by copyright, with all rights reserved, unless otherwise indicated.","Restricted Item. 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This scheme is particularly suitable in the micro range where the loads are generally single-phase or unbalanced three-phase type. A scheme of reconfiguring the existing static excitation is suggested which results in a balanced condition at a partial rating, and as a consequence considerable improvement in the de-rating factor is achieved. Alternatively extra reactive components are required to balance a single-phase load of the full three-phase rating. A generalized condition for balancing is developed and analytical relationships are derived for de-rating an induction motor. However, such analytical treatments are difficult for induction generators therefore a comprehensive method of modelling a three-phase induction generator under unbalanced excitation and loading is presented. The de-rating and voltage regulation characteristics computed from this model are checked against test results on a laboratory machine. In an attempt to make a microhydro system economical, such unconventional equipment as a reverse mode centrifugal pump and an Electronic Load Governor are used. The economics of using the unconventional equipment are compared to the conventional situation. A full fledged microhydro test rig is developed with unconventional equipment, and the design and selection method is discussed. In order to add such features as improved reliability, load factor and economic scheduling, parallel operation with a minigrid system is considered. The synchronizing transients observed on the test rig are of an unusual nature while the steady state performance is satisfactory. A simulation study is conducted to identify the cause of the unusual nature of synchronizing transients and to suggest measures to avoid them. Both electrical and hydraulic systems are represented. A new concept for modelling the electrical system is presented and the hydraulic system model is deduced from established models. However, all parameters of the hydraulic model are not known. An identification study is conducted on the input-output characteristics of the model to determine those parameters. The study also reveals the cause of the unusual nature of the synchronizing transients and possible corrective actions are suggested. Further investigations are carried out to establish the use of induction generators in minihydro systems as a viable alternative. It is found that the economic viability depends on meeting the excitation requirements by other synchronous generators and as such they may be operated in parallel with a power system network where there are other synchronous generators. Consequently the operation of the minihydro system is studied in conjunction with other thermal and hydro power stations. A real-time simulation method is used for reasons of accuracy, indepth comprehension and easy monitoring of variables. In this real-time simulation study sub-systems like the induction generator and turbogenerator are replaced by their real physical scaled down models while others are simulated on microcomputers controlling these generators. The chief purpose of the real-time simulation model is to study the behaviour of a minihydro power station using an induction generator in an interconnected system. However, the presence of a combination of thermal and hydro power station creates a problem of hydrothermal coordination. The role of an automatic generation controller is adequately represented and a controller is developed for the minihydro power station. Successful implementation of the hydrothermal coordination then establishes the credibility of the operation of a minihydro station in this situation."]},{"key":"dc:title","label":"Title","values":["Induction generators in mini and micro hydro applications as a low cost alternative"]}]}],"canonical_facts":{"dc:contributor.advisor":["Woodward, J.L.","Boys, J.T."],"dc:creator":["Bhattacharya, Jayant Lal"],"dc:date.accessioned":["2020-06-02T04:32:04Z"],"dc:date.available":["2020-06-02T04:32:04Z"],"dc:date.issued":["1988"],"dc:description":["Full text is available to authenticated members of The University of Auckland only."],"dc:description.abstract":["This study develops low cost techniques for mini and micro hydro power generation with the chief concern of investigating induction generators as a viable alternative. A method of reconfiguring the static excitation of a self-excited induction generator is studied to supply a single-phase or an unbalanced three-phase load using a standard three-phase machine. This scheme is particularly suitable in the micro range where the loads are generally single-phase or unbalanced three-phase type. A scheme of reconfiguring the existing static excitation is suggested which results in a balanced condition at a partial rating, and as a consequence considerable improvement in the de-rating factor is achieved. Alternatively extra reactive components are required to balance a single-phase load of the full three-phase rating. A generalized condition for balancing is developed and analytical relationships are derived for de-rating an induction motor. However, such analytical treatments are difficult for induction generators therefore a comprehensive method of modelling a three-phase induction generator under unbalanced excitation and loading is presented. The de-rating and voltage regulation characteristics computed from this model are checked against test results on a laboratory machine. In an attempt to make a microhydro system economical, such unconventional equipment as a reverse mode centrifugal pump and an Electronic Load Governor are used. The economics of using the unconventional equipment are compared to the conventional situation. A full fledged microhydro test rig is developed with unconventional equipment, and the design and selection method is discussed. In order to add such features as improved reliability, load factor and economic scheduling, parallel operation with a minigrid system is considered. The synchronizing transients observed on the test rig are of an unusual nature while the steady state performance is satisfactory. A simulation study is conducted to identify the cause of the unusual nature of synchronizing transients and to suggest measures to avoid them. Both electrical and hydraulic systems are represented. A new concept for modelling the electrical system is presented and the hydraulic system model is deduced from established models. However, all parameters of the hydraulic model are not known. An identification study is conducted on the input-output characteristics of the model to determine those parameters. The study also reveals the cause of the unusual nature of the synchronizing transients and possible corrective actions are suggested. Further investigations are carried out to establish the use of induction generators in minihydro systems as a viable alternative. It is found that the economic viability depends on meeting the excitation requirements by other synchronous generators and as such they may be operated in parallel with a power system network where there are other synchronous generators. Consequently the operation of the minihydro system is studied in conjunction with other thermal and hydro power stations. A real-time simulation method is used for reasons of accuracy, indepth comprehension and easy monitoring of variables. In this real-time simulation study sub-systems like the induction generator and turbogenerator are replaced by their real physical scaled down models while others are simulated on microcomputers controlling these generators. The chief purpose of the real-time simulation model is to study the behaviour of a minihydro power station using an induction generator in an interconnected system. However, the presence of a combination of thermal and hydro power station creates a problem of hydrothermal coordination. The role of an automatic generation controller is adequately represented and a controller is developed for the minihydro power station. Successful implementation of the hydrothermal coordination then establishes the credibility of the operation of a minihydro station in this situation."],"dc:identifier.uri":["https://hdl.handle.net/2292/50984"],"dc:publisher":["ResearchSpace@Auckland"],"dc:relation.isreferencedby":["UoA9974688414002091"],"dc:rights":["Items in ResearchSpace are protected by copyright, with all rights reserved, unless otherwise indicated.","Restricted Item. Full text is available to authenticated members of The University of Auckland only."],"dc:rights.uri":["https://researchspace.auckland.ac.nz/docs/uoa-docs/rights.htm"],"dc:title":["Induction generators in mini and micro hydro applications as a low cost alternative"],"dc:type":["Thesis"],"thesis:degree_discipline":["Electrical and Electronic Engineering"],"thesis:degree_level":["Doctoral"],"thesis:degree_name":["PhD"],"thesis:institution_name":["The University of Auckland"]},"updated_at":"2026-07-24T01:07:07Z"}