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Assignment on Transient Analysis and Surge Protection

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Added on  2020-04-07

Assignment on Transient Analysis and Surge Protection

   Added on 2020-04-07

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Running head: TRANSIENT ANALYSIS AND SURGE PROTECTION1Transient analysis and surge protection.AuthorCourseDate
Assignment on Transient Analysis and Surge Protection_1
TRANSIENT ANALYSIS AND SURGE PROTECTION2Question 1System data:Generator G1 : 25 MVA, 15% reactanceGenerator G2 : 50 MVA, 20% reactanceTransformer T1 : 100 MVA, 8% reactanceTransformer T2 : 40 MVA, 10% reactanceShort-circuit rupturing capacity of the feeder circuit breaker B : 333MVABase MVA : 100Calculating for the reactance of the generators and transformers in per unit:pu = reactance * baseMVAMVAratingGenerator G1 = 0.15 * 10025 = 0.6 puGenerator G2 = 0.2 * 10050 = 0.4 puTransformer T1 = 0.08 * 100100 = 0.08 puTransformer T2 = 0.1 * 10040 = 0.25 puThe short-circuit rupturing capacity of the breaker is 333100 = 3.33 pu3.33−1 = 0.30 (equivalent system reactance) Hence the equivalent system reactance at the generator bus is the difference of the equivalent system reactance and the reactance of transformer T1:0.3 - 0.08 = 0.22 puSolving for the inductive reactance:10.6 + 10.4 + 10.25+a = 10.22
Assignment on Transient Analysis and Surge Protection_2
TRANSIENT ANALYSIS AND SURGE PROTECTION310.25+a = 256666= 25a + 6.25a= 2.39The reactance required is 2.39 pu.Question 2System data Generator 1: 25 MVA, 11kV, X'' = 0.2, X2= 0.15, X0= 0.03 puGenerator 2: 15 MVA, 11kV, X'' = 0.2, X2= 0.15, X0= 0.05 puSynchronous motor 3: 25 MVA, 11kV, X'' = 0.2, X2= 0.2, X0= 0.1 puTransformer 1: 25 MVA, 11/120Y kV, X=10%Transformer 2: 12.5 MVA, 11/120Y kV, X=10%Transformer 3: 10 MVA, 120Y/11Y kV, X=10%Base of 50MVA, 11kV in circuit of generator 1.Zero sequence reactance of each line = 250% of its positive sequence reactance.a)Positive sequence networkGenerator 1: X" = 0.2 * baseMVAratedMVA = 0.2 * 5025 = 0.4Generator 2: X" = 0.2 * baseMVAratedMVA = 0.2 * 5015 = 0.667Synchronous motor : X"=0.2 * baseMVAratedMVA = 0.2 * 5025 = 0.4Transformer 1 : 0.1 * baseMVAratedMVA = 0.1 * 5025 = 0.2Transformer 2 : 0.1 * baseMVAratedMVA = 0.1 * 5012.5 = 0.4Transformer 3 : 0.1 * baseMVAratedMVA = 0.1 * 5010 = 0.5Each transmission line : 25 * baseMVAkV2 = 25 * 501202 = 0.0868
Assignment on Transient Analysis and Surge Protection_3
TRANSIENT ANALYSIS AND SURGE PROTECTION4b)Negative sequence networkGenerator 1: X2 = 0.15 * baseMVAratedMVA = 0.15 * 5025 = 0.3Generator 2: X2 = 0.15 * baseMVAratedMVA = 0.15 * 5015 = 0.5Synchronous motor :X2= 0.2 * baseMVAratedMVA = 0.2 * 5025 = 0.4Transformer 1 : 0.2Transformer 2 : 0.4Transformer 3 : 0.5Each transmission line : 0.0868
Assignment on Transient Analysis and Surge Protection_4

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