The paper reviews the improvement obtained in the performance of side-vented explosion pots when they are shunted by resistors.First, it is shown that the rating of explosion pots is determined by two critical regions, one of which determines the maximum voltage rating, whilst the other determines the maximum breaking-current rating. The effect of resistors on these critical regions is first described and then illustrated by actual test results.Secondly, it is shown that the resistors shunting the pots can also be used to give even voltage-distribution over several pots in series.The application of resistors in practice is illustrated by the description of a 132-kV oil circuit-breaker rated at 2,500 MVA.The effect of the resistors when breaking small currents in inductive and capacitive circuits is discussed in detail.A discussion follows on the validity of testing separately one pole of a 3-phase separate-tank breaker, having two breaks per pole, by applying the full 3-phase output of the test plant, the third Jerminal being obtained by bringing out through the tank wall a connection from the moving cross-bar.In conclusion, actual performances are illustrated by test results obtained on one pole of a 3-phase, 132-kV, 2,500-MVA breaker.
{"title":"The performance of high-voltage oil circuit-breakers incorporating resistance switching","authors":"H. E. Cox, T. W. Wilcox","doi":"10.1049/JI-2.1947.0105","DOIUrl":"https://doi.org/10.1049/JI-2.1947.0105","url":null,"abstract":"The paper reviews the improvement obtained in the performance of side-vented explosion pots when they are shunted by resistors.First, it is shown that the rating of explosion pots is determined by two critical regions, one of which determines the maximum voltage rating, whilst the other determines the maximum breaking-current rating. The effect of resistors on these critical regions is first described and then illustrated by actual test results.Secondly, it is shown that the resistors shunting the pots can also be used to give even voltage-distribution over several pots in series.The application of resistors in practice is illustrated by the description of a 132-kV oil circuit-breaker rated at 2,500 MVA.The effect of the resistors when breaking small currents in inductive and capacitive circuits is discussed in detail.A discussion follows on the validity of testing separately one pole of a 3-phase separate-tank breaker, having two breaks per pole, by applying the full 3-phase output of the test plant, the third Jerminal being obtained by bringing out through the tank wall a connection from the moving cross-bar.In conclusion, actual performances are illustrated by test results obtained on one pole of a 3-phase, 132-kV, 2,500-MVA breaker.","PeriodicalId":307627,"journal":{"name":"Journal of the Institution of Electrical Engineers - Part II: Power Engineering","volume":"75 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1947-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122541932","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"The author's reply to the discussions on \"Power supply for generating station auxiliary services\"","authors":"W. Szwander","doi":"10.1049/JI-2.1947.0116","DOIUrl":"https://doi.org/10.1049/JI-2.1947.0116","url":null,"abstract":"","PeriodicalId":307627,"journal":{"name":"Journal of the Institution of Electrical Engineers - Part II: Power Engineering","volume":"22 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1947-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122854569","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"The author's reply to the discussion on 'Electrical control of dangerous machinery and processes'","authors":"W. Cooper","doi":"10.1049/JI-2.1947.0077","DOIUrl":"https://doi.org/10.1049/JI-2.1947.0077","url":null,"abstract":"","PeriodicalId":307627,"journal":{"name":"Journal of the Institution of Electrical Engineers - Part II: Power Engineering","volume":"44 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1947-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123955811","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The success attained in the burning of semi-bituminous and bituminous fuels has established pulverized-fuel firing in dry-ash bottom furnaces as the preferred method of combustion for power stations in Great Britain. The tendency to divert a high proportion of the poorest quality coal to these new power stations should be viewed with alarm. Owing to the variable quality of ash and the limitations imposed by the presence of this refuse in increasing quantity, boiler units must be moderately rated to maintain satisfactory availability. Combustion rates must be controlled to obviate slagging and birdnesting with the most unfavourable fuel, and this involves the provision of comparatively large furnaces for the duty. For boiler units much in excess of 400 000 lb/h a strong case can be established for using specially-selected fuel, or, alternatively, liquid ash-removal may be employed. In either case, the fine dust from the arresters must be disposed of, and this frequently proves both difficult and expensive. With a view to solving this serious problem, as well as offsetting the disadvantages of variable ash characteristics, the cyclone furnace has been evolved and is at present undergoing trials in the United States, whilst overfeed firing with moving grates has already been developed there for application to boiler units of suitable size for power-station work. Some considerable increase in the output of dust fuel appears probable as the result of increased mechanization in the mines, so that in these circumstances pulverized-coal-fired boilers will always be in demand to dispose of this, unless it is eventually found more profitable to upgrade it for other processes.
{"title":"The future of pulverized-coal firing in Great Britain","authors":"C. H. Sparks","doi":"10.1049/JI-2.1947.0118","DOIUrl":"https://doi.org/10.1049/JI-2.1947.0118","url":null,"abstract":"The success attained in the burning of semi-bituminous and bituminous fuels has established pulverized-fuel firing in dry-ash bottom furnaces as the preferred method of combustion for power stations in Great Britain. The tendency to divert a high proportion of the poorest quality coal to these new power stations should be viewed with alarm. Owing to the variable quality of ash and the limitations imposed by the presence of this refuse in increasing quantity, boiler units must be moderately rated to maintain satisfactory availability. Combustion rates must be controlled to obviate slagging and birdnesting with the most unfavourable fuel, and this involves the provision of comparatively large furnaces for the duty. For boiler units much in excess of 400 000 lb/h a strong case can be established for using specially-selected fuel, or, alternatively, liquid ash-removal may be employed. In either case, the fine dust from the arresters must be disposed of, and this frequently proves both difficult and expensive. With a view to solving this serious problem, as well as offsetting the disadvantages of variable ash characteristics, the cyclone furnace has been evolved and is at present undergoing trials in the United States, whilst overfeed firing with moving grates has already been developed there for application to boiler units of suitable size for power-station work. Some considerable increase in the output of dust fuel appears probable as the result of increased mechanization in the mines, so that in these circumstances pulverized-coal-fired boilers will always be in demand to dispose of this, unless it is eventually found more profitable to upgrade it for other processes.","PeriodicalId":307627,"journal":{"name":"Journal of the Institution of Electrical Engineers - Part II: Power Engineering","volume":"58 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1947-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129346284","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Equivalent circuits representing simultaneous dissymmetries on 3-phase systems have been treated previously, 1, 2, 3 but the analysis has been purely mathematical and the ultimate evaluations have been formal. In this paper the more direct method of superposition is employed, as this retains the physical aspect and in general reduces the labour of computation; it also has the indirect advantage that the faults are developed in proper sequence.All possible combinations of two dissymmetries are analysed, with the exception of simultaneous open-circuits. The results are tabulated suitably for direct computation.The primary operation is to reduce the symmetrical-component sequence networks of a given system to the simplest arrangement of impedances between the source and the dissymmetry locations. The networks are then interconnected so that the pertinent constraints between the sequence currents and voltages are complied with at both locations. In general the interconnections at one location can be made direct, whereas at the other magnetic coupling will be required. The constraints and the direct- and magnetically-coupled interconnections for all types of faults and open-circuits are tabulated.The interconnections for any particular dissymmetry can be introduced for faults by the closure, and for open-circuits by the opening, of a switch. The procedure employed is, with the switch (S1) controlling the magnetic interconnections open, to close or open the switch (S2) controlling the direct interconnections, and to determine the current and voltage distributions throughout the network, in particular the voltage across S1. The current or voltage distribution which would be due to the closure of S1 is then determined by an operation equivalent to closing it, i.e. by applying across its terminals a voltage equal and opposite to that determined from the operation of S2. The actual current or voltage distribution for the simultaneous dissymmetries is then the vector sum of the distributions due to the closure (or opening) of S2 and the equivalent closure of S1.
{"title":"The evaluation of simultaneous faults on three-phase systems","authors":"J. Mortlock","doi":"10.1049/JI-2.1947.0061","DOIUrl":"https://doi.org/10.1049/JI-2.1947.0061","url":null,"abstract":"Equivalent circuits representing simultaneous dissymmetries on 3-phase systems have been treated previously, 1, 2, 3 but the analysis has been purely mathematical and the ultimate evaluations have been formal. In this paper the more direct method of superposition is employed, as this retains the physical aspect and in general reduces the labour of computation; it also has the indirect advantage that the faults are developed in proper sequence.All possible combinations of two dissymmetries are analysed, with the exception of simultaneous open-circuits. The results are tabulated suitably for direct computation.The primary operation is to reduce the symmetrical-component sequence networks of a given system to the simplest arrangement of impedances between the source and the dissymmetry locations. The networks are then interconnected so that the pertinent constraints between the sequence currents and voltages are complied with at both locations. In general the interconnections at one location can be made direct, whereas at the other magnetic coupling will be required. The constraints and the direct- and magnetically-coupled interconnections for all types of faults and open-circuits are tabulated.The interconnections for any particular dissymmetry can be introduced for faults by the closure, and for open-circuits by the opening, of a switch. The procedure employed is, with the switch (S1) controlling the magnetic interconnections open, to close or open the switch (S2) controlling the direct interconnections, and to determine the current and voltage distributions throughout the network, in particular the voltage across S1. The current or voltage distribution which would be due to the closure of S1 is then determined by an operation equivalent to closing it, i.e. by applying across its terminals a voltage equal and opposite to that determined from the operation of S2. The actual current or voltage distribution for the simultaneous dissymmetries is then the vector sum of the distributions due to the closure (or opening) of S2 and the equivalent closure of S1.","PeriodicalId":307627,"journal":{"name":"Journal of the Institution of Electrical Engineers - Part II: Power Engineering","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1947-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121919605","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"The author's reply to the discussion on 'Some notes on transformer practice with reference to standardization'","authors":"A. G. Ellis","doi":"10.1049/JI-2.1946.0069","DOIUrl":"https://doi.org/10.1049/JI-2.1946.0069","url":null,"abstract":"","PeriodicalId":307627,"journal":{"name":"Journal of the Institution of Electrical Engineers - Part II: Power Engineering","volume":"109 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1947-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127314302","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A number of accidents occur with dangerous machinery and processes, which though not of an electrical character, such as electric shock or burns, are due to the failure of electrical control equipment, or could have been prevented by the use of suitable electrical control or protective gear. This paper discusses such matters in as systematic a manner as their varied character allows. Typical instances are interlocking of danger areas, design and adjustment of limit switches, safety equipment on cranes and lifts, pushbutton circuits and the prevention of inadvertent starting of dangerous machines. The dangers from fire risks have been dealt with in an earlier paper in association with Mr. F.H. Mann, and the author has given some account of furnace control elsewhere. The author would point out that the conclusions and suggestions set out below are his own. They are relevant to the present stage of development of electrical control, and are subject to modification in the light of further experience. They do not necessarily represent the views or considered policy of his Department.
{"title":"Electrical control of dangerous machinery and processes","authors":"W. Cooper","doi":"10.1049/JI-2.1947.0075","DOIUrl":"https://doi.org/10.1049/JI-2.1947.0075","url":null,"abstract":"A number of accidents occur with dangerous machinery and processes, which though not of an electrical character, such as electric shock or burns, are due to the failure of electrical control equipment, or could have been prevented by the use of suitable electrical control or protective gear. This paper discusses such matters in as systematic a manner as their varied character allows. Typical instances are interlocking of danger areas, design and adjustment of limit switches, safety equipment on cranes and lifts, pushbutton circuits and the prevention of inadvertent starting of dangerous machines. The dangers from fire risks have been dealt with in an earlier paper in association with Mr. F.H. Mann, and the author has given some account of furnace control elsewhere. The author would point out that the conclusions and suggestions set out below are his own. They are relevant to the present stage of development of electrical control, and are subject to modification in the light of further experience. They do not necessarily represent the views or considered policy of his Department.","PeriodicalId":307627,"journal":{"name":"Journal of the Institution of Electrical Engineers - Part II: Power Engineering","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1947-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122481136","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The development of the gas-cushion cable over the last ten years for the highest voltages is traced from the point of view of performance under tests which have been formulated to give data for design purposes. Comparison is made with the normal solid cable-dielectrics under 50-c/s and impulse conditions. The special requirements pertaining to impulse testing when dealing with cables are enunciated, and the present dearth of data in this respect is revealed. Reference is made to possible future developments.
{"title":"The development of the gas-cushion cable system for the highest voltages","authors":"T. Harrison","doi":"10.1049/JI-2.1947.0078","DOIUrl":"https://doi.org/10.1049/JI-2.1947.0078","url":null,"abstract":"The development of the gas-cushion cable over the last ten years for the highest voltages is traced from the point of view of performance under tests which have been formulated to give data for design purposes. Comparison is made with the normal solid cable-dielectrics under 50-c/s and impulse conditions. The special requirements pertaining to impulse testing when dealing with cables are enunciated, and the present dearth of data in this respect is revealed. Reference is made to possible future developments.","PeriodicalId":307627,"journal":{"name":"Journal of the Institution of Electrical Engineers - Part II: Power Engineering","volume":"94 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1947-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129068109","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"The author's reply to the discussion on 'The development of the gas-cushion cable system for the highest voltages'","authors":"T. Harrison","doi":"10.1049/JI-2.1947.0080","DOIUrl":"https://doi.org/10.1049/JI-2.1947.0080","url":null,"abstract":"","PeriodicalId":307627,"journal":{"name":"Journal of the Institution of Electrical Engineers - Part II: Power Engineering","volume":"111 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1947-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115379514","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The Wheatstone bridge method of resistance measurement is noted for its simplicity, accuracy and reliability. It is claimed that these attributes can be retained in remote-indication systems which employ the principle of the balanced bridge. This method ensures freedom from any undesirable effects of self-inductance, capacitance, induced voltage or supply-voltage variation within normal limits. A detailed description is given of an automatic signalling system of this type which has been in continuous operation since 1929 in Georgetown, British Guiana, under extremely onerous conditions. The paper also indicates how the balanced-bridge principle may be developed to superimpose telemetering facilities on a single-pair telephone circuit. Two appendices set out general formulae and examples of their application in the design of the Georgetown installation.
{"title":"Remote indication by a Wheatstone bridge system","authors":"I. M. Aitken","doi":"10.1049/JI-2.1947.0064","DOIUrl":"https://doi.org/10.1049/JI-2.1947.0064","url":null,"abstract":"The Wheatstone bridge method of resistance measurement is noted for its simplicity, accuracy and reliability. It is claimed that these attributes can be retained in remote-indication systems which employ the principle of the balanced bridge. This method ensures freedom from any undesirable effects of self-inductance, capacitance, induced voltage or supply-voltage variation within normal limits. A detailed description is given of an automatic signalling system of this type which has been in continuous operation since 1929 in Georgetown, British Guiana, under extremely onerous conditions. The paper also indicates how the balanced-bridge principle may be developed to superimpose telemetering facilities on a single-pair telephone circuit. Two appendices set out general formulae and examples of their application in the design of the Georgetown installation.","PeriodicalId":307627,"journal":{"name":"Journal of the Institution of Electrical Engineers - Part II: Power Engineering","volume":"55 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1947-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122990742","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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