ERACSAssign Dr. M.W.Renton Page 1 of 2 01/02/17 Power Systems (Analysis) ELE10104 Power Systems - Coursework Assignment Introduction The single-line diagram of a 4-bus power system is shown in Figure 1. Bus 1 is the slack bus (voltage-controlled). The complex powers at each bus are shown in the system diagram. The line p.u. impedances are given in Table 1. Use base values of 100 MVA and 33 kV for all calculations. Figure 1 – Single-line Diagram (all p.u.) Line connecting bus 1 and 2 0.02 + j0.14 Line connecting bus 1 and 3 0.04 + j0.2 Line connecting bus 2 and 4 0.12 + j0.3 Line connecting bus 3 and 4 0.1 + j0.21 Table 1 – Line Impedances (p.u. on 100 MVA, 33 kV base) Part 1 - Load flow Study  Determine the bus admittance matrix [Ybus];  Manually formulate the load flow equations and solve for: (a) all bus voltages (b) all current flows (c) all power flows;  Model this power system on the ERACS power system analysis package; o At Bus 1, the generation is a 100 MVA synchronous generator with a positive sequence reactance of j0.1 p.u. (on study base). Note: this generator reactance only features in the fault analysis calculation. o For Buses 2, 3 and 4 the power injections are represented by shunt loads.  Confirm the results of your manual load flow calculation by running a load flow on the ERACS model. V1 = 1.04/0° p.u. 1 2 3 4 V2 V3 V4 P1 + jQ1 - 0.15 + j0.5 0.4 – j 0.2 0.3 – j0.1ERACSAssign Dr. M.W.Renton Page 2 of 2 01/02/17 Power Systems (Analysis) Part 2 – Symmetrical Fault Analysis  For all fault calculations and simulations neglect the resistive component of the lines and switch-out the shunt loads. Note: An additional ERACS data state (or copied file) must be created with the line resistance values set to zero.  Determine [Zbus] taking the generator as reference.  For a symmetrical three-phase fault on Bus 4, manually calculate: (a) the fault current, (b) all bus voltages, and (c) all current flows.  Confirm the results of your manual fault calculation by running a single fault on the previously prepared ERACS model, displaying the following results on your ERACS fault calculation printout: Summary: Phase L1 Current Fault MVA Busbar: Phase L1 Voltage Line: Phase L1 Current Report Guidelines The report should contain, at least:  Details of how the elements of [Ybus] and [Zbus] were obtained;  The complete, detailed load-flow and fault solution with the results of all bus voltages, current and power flows summarised on a system diagram;  The computer printout showing the appropriate load-flow and fault data values generated by the ERACS simulation;  A comparison and discussion of the results from the ERACS and manual calculations. Marking Marks awarded will reflect the presentation and content of the report as well as the accuracy of both the computer model and all numerical results. The marks available for each element are as follows: Presentation 15 Theory 10 ERACS simulation 20 Manual Calculation 30 Discussion/conclusion 25 This assignment contributes 40% to the overall module assessment. Submission The assignment report should be submitted in accordance with the Assessment Datasheet.