// Numbas version: finer_feedback_settings
{"name": "Fault Analysis 3 Bus", "extensions": [], "custom_part_types": [], "resources": [["question-resources/FA3Bus.png", "/srv/numbas/media/question-resources/FA3Bus.png"]], "navigation": {"allowregen": true, "showfrontpage": false, "preventleave": false, "typeendtoleave": false}, "question_groups": [{"pickingStrategy": "all-ordered", "questions": [{"name": "Fault Analysis 3 Bus", "tags": [], "metadata": {"description": "", "licence": "None specified"}, "statement": "<p style=\"text-align: center;\">In the system shown in <strong>Figure 1</strong>, the transformer is connected star-star with both star points grounded and the generator is connected in star with its star point grounded. The per unit sequence reactances of each element on a {SBASE} MVA base are given in <strong>Table 1</strong> and the voltage levels are given in <strong>Table 2</strong>.</p>\n<p style=\"text-align: center;\">{image('resources/question-resources/FA3Bus.png')}</p>\n<p style=\"text-align: center;\"><strong><em>Figure 1: A section of the distribution system</em></strong></p>\n<table border=\"1\" cellpadding=\"1\" style=\"margin-left: auto; margin-right: auto;\">\n<tbody>\n<tr>\n<td width=\"74\" style=\"text-align: center;\">\n<p>&nbsp;</p>\n</td>\n<td width=\"74\" style=\"text-align: center;\">\n<p><strong>G1</strong></p>\n</td>\n<td width=\"74\" style=\"text-align: center;\">\n<p><strong>T1</strong></p>\n</td>\n<td width=\"74\" style=\"text-align: center;\">\n<p style=\"text-align: center;\"><strong>L</strong></p>\n</td>\n</tr>\n<tr>\n<td width=\"74\" style=\"text-align: center;\">\n<p><strong>X<sub>1</sub></strong></p>\n</td>\n<td width=\"74\" style=\"text-align: center;\">\n<p>{G12}</p>\n</td>\n<td width=\"74\" style=\"text-align: center;\">\n<p>{T120}</p>\n</td>\n<td width=\"74\" style=\"text-align: center;\">\n<p>{L12}</p>\n</td>\n</tr>\n<tr>\n<td width=\"74\" style=\"text-align: center;\">\n<p><strong>X<sub>2</sub></strong></p>\n</td>\n<td width=\"74\" style=\"text-align: center;\">\n<p>{G12}</p>\n</td>\n<td width=\"74\" style=\"text-align: center;\">\n<p>{T120}</p>\n</td>\n<td width=\"74\" style=\"text-align: center;\">\n<p>{L12}</p>\n</td>\n</tr>\n<tr>\n<td width=\"74\" style=\"text-align: center;\">\n<p><strong>X<sub>0</sub></strong></p>\n</td>\n<td width=\"74\" style=\"text-align: center;\">\n<p>{G0}</p>\n</td>\n<td width=\"74\" style=\"text-align: center;\">\n<p>{T120}</p>\n</td>\n<td width=\"74\" style=\"text-align: center;\">\n<p>{L0}</p>\n</td>\n</tr>\n</tbody>\n</table>\n<p style=\"text-align: center;\"><em><strong></strong></em><em><strong>&nbsp;Table 1: Sequence reactances (p.u. on {SBASE} MVA base)</strong></em></p>\n<p style=\"text-align: center;\"><em><strong></strong></em></p>\n<table border=\"1\" cellpadding=\"1\" style=\"margin-left: auto; margin-right: auto;\">\n<tbody>\n<tr>\n<td width=\"74\" style=\"text-align: center;\">\n<p>&nbsp;</p>\n</td>\n<td width=\"74\" style=\"text-align: center;\">\n<p><strong>G1</strong></p>\n</td>\n<td width=\"74\" style=\"text-align: center;\">\n<p><strong>T1</strong></p>\n</td>\n<td width=\"74\" style=\"text-align: center;\">\n<p><strong>L</strong></p>\n</td>\n</tr>\n<tr>\n<td width=\"74\" style=\"text-align: center;\">\n<p><strong>V&nbsp;<sub>BASE</sub></strong></p>\n</td>\n<td width=\"74\" style=\"text-align: center;\">\n<p>{VG}</p>\n</td>\n<td width=\"74\" style=\"text-align: center;\">\n<p>{VG}/{VL}</p>\n</td>\n<td width=\"74\" style=\"text-align: center;\">\n<p>{VL}</p>\n</td>\n</tr>\n</tbody>\n</table>\n<p style=\"text-align: center;\"><em><strong>Table 1: Voltage bases (kV)</strong></em></p>\n<p style=\"text-align: center;\"><strong><em></em></strong></p>", "advice": "", "rulesets": {}, "extensions": [], "builtin_constants": {"e": true, "pi,\u03c0": true, "i": true}, "constants": [], "variables": {"VL": {"name": "VL", "group": "Ungrouped variables", "definition": "random(20 .. 50#2)", "description": "", "templateType": "randrange", "can_override": false}, "G12": {"name": "G12", "group": "Ungrouped variables", "definition": "random(0.05 .. 0.15#0.01)", "description": "", "templateType": "randrange", "can_override": false}, "G0": {"name": "G0", "group": "Ungrouped variables", "definition": "precround(ratio*G12,2)", "description": "", "templateType": "anything", "can_override": false}, "L0": {"name": "L0", "group": "Ungrouped variables", "definition": "random(0.05 .. 0.15#0.01)", "description": "", "templateType": "randrange", "can_override": false}, "L12": {"name": "L12", "group": "Ungrouped variables", "definition": "precround(ratio*L0,2)", "description": "", "templateType": "anything", "can_override": false}, "T120": {"name": "T120", "group": "Ungrouped variables", "definition": "random(0.05 .. 0.15#0.01)", "description": "", "templateType": "randrange", "can_override": false}, "VG": {"name": "VG", "group": "Ungrouped variables", "definition": "random(1 .. 10#1)", "description": "", "templateType": "randrange", "can_override": false}, "ratio": {"name": "ratio", "group": "Ungrouped variables", "definition": "random(0.5 .. 0.9#0.1)", "description": "", "templateType": "randrange", "can_override": false}, "SBASE": {"name": "SBASE", "group": "Ungrouped variables", "definition": "random(10 .. 100#10)", "description": "", "templateType": "randrange", "can_override": false}, "I1": {"name": "I1", "group": "Calculated", "definition": "-i/(2*X12)", "description": "", "templateType": "anything", "can_override": false}, "IFkA": {"name": "IFkA", "group": "Calculated", "definition": "IFpu*SBASE/(sqrt(3)*VL)", "description": "", "templateType": "anything", "can_override": false}, "IGkA": {"name": "IGkA", "group": "Calculated", "definition": "IFpu*SBASE/(sqrt(3)*VG)", "description": "", "templateType": "anything", "can_override": false}, "X0": {"name": "X0", "group": "Calculated", "definition": "G0+T120+L0", "description": "", "templateType": "anything", "can_override": false}, "X12": {"name": "X12", "group": "Calculated", "definition": "G12+T120+L12", "description": "", "templateType": "anything", "can_override": false}, "AMatrix": {"name": "AMatrix", "group": "Calculated", "definition": "matrix([1,1,1],[1,a^2,a],[1,a,a^2])", "description": "", "templateType": "anything", "can_override": false}, "a": {"name": "a", "group": "Calculated", "definition": "cos(pi*120/180)+i*sin(pi*120/180)", "description": "", "templateType": "anything", "can_override": false}, "IFpu": {"name": "IFpu", "group": "Calculated", "definition": "abs((a^2-a)*I1)", "description": "", "templateType": "anything", "can_override": false}}, "variablesTest": {"condition": "", "maxRuns": 100}, "ungrouped_variables": ["VG", "VL", "G12", "G0", "T120", "L12", "L0", "ratio", "SBASE"], "variable_groups": [{"name": "Calculated", "variables": ["I1", "IFkA", "IGkA", "X0", "X12", "AMatrix", "a", "IFpu"]}], "functions": {}, "preamble": {"js": "", "css": ""}, "parts": [{"type": "gapfill", "useCustomName": true, "customName": "Fault Current (p.u.)", "marks": 0, "scripts": {}, "customMarkingAlgorithm": "", "extendBaseMarkingAlgorithm": true, "unitTests": [], "showCorrectAnswer": true, "showFeedbackIcon": true, "variableReplacements": [], "variableReplacementStrategy": "originalfirst", "nextParts": [], "suggestGoingBack": false, "adaptiveMarkingPenalty": 0, "exploreObjective": null, "prompt": "<p>If a&nbsp;line-line fault occurs at bus&nbsp;3 with zero fault impedance, calculate the magnitude of the fault current flowing between phases at the fault point (in p.u.).</p>\n<p>$ I $ =&nbsp;&nbsp;[[0]] &nbsp;p.u.</p>", "gaps": [{"type": "numberentry", "useCustomName": true, "customName": "IFpu", "marks": "10", "scripts": {}, "customMarkingAlgorithm": "", "extendBaseMarkingAlgorithm": true, "unitTests": [], "showCorrectAnswer": true, "showFeedbackIcon": true, "variableReplacements": [], "variableReplacementStrategy": "originalfirst", "nextParts": [], "suggestGoingBack": false, "adaptiveMarkingPenalty": 0, "exploreObjective": null, "minValue": "0.99*IFpu", "maxValue": "1.01*IFpu", "correctAnswerFraction": false, "allowFractions": false, "mustBeReduced": false, "mustBeReducedPC": 0, "showFractionHint": true, "notationStyles": ["plain", "en", "si-en"], "correctAnswerStyle": "plain"}], "sortAnswers": false}, {"type": "gapfill", "useCustomName": true, "customName": "Fault Current (kA)", "marks": 0, "scripts": {}, "customMarkingAlgorithm": "", "extendBaseMarkingAlgorithm": true, "unitTests": [], "showCorrectAnswer": true, "showFeedbackIcon": true, "variableReplacements": [], "variableReplacementStrategy": "originalfirst", "nextParts": [], "suggestGoingBack": false, "adaptiveMarkingPenalty": 0, "exploreObjective": null, "prompt": "<p>What is the fault current at the fault point in kA?</p>\n<p>$ I $ =&nbsp; [[0]] kA</p>", "gaps": [{"type": "numberentry", "useCustomName": true, "customName": "IFkA", "marks": "5", "scripts": {}, "customMarkingAlgorithm": "", "extendBaseMarkingAlgorithm": true, "unitTests": [], "showCorrectAnswer": true, "showFeedbackIcon": true, "variableReplacements": [], "variableReplacementStrategy": "originalfirst", "nextParts": [], "suggestGoingBack": false, "adaptiveMarkingPenalty": 0, "exploreObjective": null, "minValue": "0.99*IFkA", "maxValue": "1.01*IFkA", "correctAnswerFraction": false, "allowFractions": false, "mustBeReduced": false, "mustBeReducedPC": 0, "showFractionHint": true, "notationStyles": ["plain", "en", "si-en"], "correctAnswerStyle": "plain"}], "sortAnswers": false}, {"type": "gapfill", "useCustomName": true, "customName": "Generator Current (kA)", "marks": 0, "scripts": {}, "customMarkingAlgorithm": "", "extendBaseMarkingAlgorithm": true, "unitTests": [], "showCorrectAnswer": true, "showFeedbackIcon": true, "variableReplacements": [], "variableReplacementStrategy": "originalfirst", "nextParts": [], "suggestGoingBack": false, "adaptiveMarkingPenalty": 0, "exploreObjective": null, "prompt": "<p>What is the fault current flowing from the generator in kA?</p>\n<p>$ I $ =&nbsp; [[0]] kA</p>", "gaps": [{"type": "numberentry", "useCustomName": true, "customName": "IGkA", "marks": "5", "scripts": {}, "customMarkingAlgorithm": "", "extendBaseMarkingAlgorithm": true, "unitTests": [], "showCorrectAnswer": true, "showFeedbackIcon": true, "variableReplacements": [], "variableReplacementStrategy": "originalfirst", "nextParts": [], "suggestGoingBack": false, "adaptiveMarkingPenalty": 0, "exploreObjective": null, "minValue": "0.99*IGkA", "maxValue": "1.01*IGkA", "correctAnswerFraction": false, "allowFractions": false, "mustBeReduced": false, "mustBeReducedPC": 0, "showFractionHint": true, "notationStyles": ["plain", "en", "si-en"], "correctAnswerStyle": "plain"}], "sortAnswers": false}], "partsMode": "all", "maxMarks": 0, "objectives": [], "penalties": [], "objectiveVisibility": "always", "penaltyVisibility": "always", "type": "question", "contributors": [{"name": "Jane Courtney", "profile_url": "https://numbas.mathcentre.ac.uk/accounts/profile/2154/"}]}]}], "contributors": [{"name": "Jane Courtney", "profile_url": "https://numbas.mathcentre.ac.uk/accounts/profile/2154/"}]}