Computer Aided Power System Design and Analysis
1. Introductions
In this assignment, a software package named ‘ERACS’ is used for diagram building of a power system, Load flow analysis, Balanced and Unbalanced Short Circuit analysis.
Calculate the short circuit level (in MVA) in balanced, the current fed into the fault and the voltages of the healthy at bus 4 of the unbalanced circuit.
Analyze and compare these two results which got by theory and analytical procedures with the system performance.
2. Procedures and Comments I. Using ERACS software package to construct the network shown below.
Figure 1.1 example network
The network diagram constructed by ERACS:
Figure 1.2 constructed network
Setting notice:
The system positive, negative and zero sequence reactances (X1, X2 and X0, respectively) are given in p.u. on 100 MVA base as follows:
G1: X1 = 0.3, X2 = 0.2 and X0 = 0.05
G2: X1 = 0.2, X2 = 0.12 and X0 = 0.03
T1: X1 = X2 = X0 = 0.15 T2: X1 = X2 = X0 = 0.1
L1 and L2: X1 = X2 = 0.15 and X0 = 0.3
Generator G1 is modeled as a slack generator with 1∠0o p.u. voltage.
Generator G2, PQ type with active power of 50 MW and reactive power of 40 MVAr.
For generators and transformers, within zero neutral earthing resistance and reactance in “Neutral Earthing Data” option. Also ignore the effects of resistance in the system.
II. Load Flow Analysis A. System analysis and problem solving
Choose the data and results options：
Busbar: Voltage (p.u.), Voltage (kV), Voltage angle ( o ) and Three Phase Fault level (MVA).
Generators, Transformers, Lines and Loads: Real power (MW) and Reactive power (MVAr).
Perform the load flow analysis (shown as figure 2.1)
Figure 2.1 load flow analysis
Give a table 2.1 for Results of Generators Transformers Lines and Loads： ComponentsP.Q | Generator1 | Transformer1 | Line1 | Line2 | Transformer2 | Generator2 | Load1 | Load 2 | Load3 | active power input | | 50Mw | 20Mw | 20Mw | 50 Mw | | 30Mw | 40Mw | 30Mw | active power
In this assignment, a software package named ‘ERACS’ is used for diagram building of a power system, Load flow analysis, Balanced and Unbalanced Short Circuit analysis.
Calculate the short circuit level (in MVA) in balanced, the current fed into the fault and the voltages of the healthy at bus 4 of the unbalanced circuit.
Analyze and compare these two results which got by theory and analytical procedures with the system performance.
2. Procedures and Comments I. Using ERACS software package to construct the network shown below.
Figure 1.1 example network
The network diagram constructed by ERACS:
Figure 1.2 constructed network
Setting notice:
The system positive, negative and zero sequence reactances (X1, X2 and X0, respectively) are given in p.u. on 100 MVA base as follows:
G1: X1 = 0.3, X2 = 0.2 and X0 = 0.05
G2: X1 = 0.2, X2 = 0.12 and X0 = 0.03
T1: X1 = X2 = X0 = 0.15 T2: X1 = X2 = X0 = 0.1
L1 and L2: X1 = X2 = 0.15 and X0 = 0.3
Generator G1 is modeled as a slack generator with 1∠0o p.u. voltage.
Generator G2, PQ type with active power of 50 MW and reactive power of 40 MVAr.
For generators and transformers, within zero neutral earthing resistance and reactance in “Neutral Earthing Data” option. Also ignore the effects of resistance in the system.
II. Load Flow Analysis A. System analysis and problem solving
Choose the data and results options：
Busbar: Voltage (p.u.), Voltage (kV), Voltage angle ( o ) and Three Phase Fault level (MVA).
Generators, Transformers, Lines and Loads: Real power (MW) and Reactive power (MVAr).
Perform the load flow analysis (shown as figure 2.1)
Figure 2.1 load flow analysis
Give a table 2.1 for Results of Generators Transformers Lines and Loads： ComponentsP.Q | Generator1 | Transformer1 | Line1 | Line2 | Transformer2 | Generator2 | Load1 | Load 2 | Load3 | active power input | | 50Mw | 20Mw | 20Mw | 50 Mw | | 30Mw | 40Mw | 30Mw | active power
References: 1 ERACS “User Guide” and “Technical Manual” available online in ERCAS Help menu. 2 eLearning Portal (Blackboard), “Module documents”, in particular: Active and Reactive Power Flow Fundamentals of Load Flow Analysis Balanced and Unbalanced Fault Calculations in Power Systems 3 WEEDY, B.M. and CORY B.J.: ‘Electric Power Systems’ (Wiley) 1998 4 CHAPMAN, S.: “Electric Machinery and Power System Fundamentals”, (McGraw Hill), 2002.