California State Polytechnic University Pomona Department of Electrical and Computer Engineering ECE 5750 Distribution system and power quality - Spring 2020 Project Project requirements: 1. The project must be completed using MATLAB/Simulink/Simscape Power Systems. Analytical hand calculation may be used for analyses and for presenting the results in the project report. You can work alone or in a group of two partners. 2. Submit your project report via email to the instructor by midnight on the due date. 3. Save your Matlab code (for Part 1) and Simulink project (for Part 2) with a name in the format 5750_yourlastname_firstname_Project.m or .slx and submit them via email to the instructor. If you work with a partner, the file name should be 5750_lastnamePartner1_lastnamePartner2_Project.m or .slx. 1. Design of a distribution system Design a small distribution system which has realistic features. The main requirements are as follows: 1) The system must have at least two feeders which are 3-phase or 3-phase 4-wire, with or without 1-phase and 2-phase laterals. Each feeder must have 3 or more buses, and at least two loads which are connected to two different buses. 2) The system must have a substation (e.g. 34.5kV/4.16kV) and some service transformers (e.g. 4.16kV/240-120V. The service transformers must accommodate loads of residential customers i.e. both 240-V and 120-V loads. 3) The power lines must have specified configuration, conductor type for phase and neutral conductors (e.g. overhead line in Problem 1 of Homework 1), and length. They can be overhead or underground lines, or combination of them. 4) The system must have at least one constant PQ load and one induction motor. The system total load power factor must be in the range of 0.85-0.95 lagging. 5) The system data (transformers, lines, loads etc.) may be taken from textbooks or other sources. Provide the data in Table 1. Also provide in “Reference” section at the end of the project report the sources where the data are obtained. Perform the following tasks: 1) Draw one-line diagram of the distribution system. It must show all pertinent components including location of loads, and must specify each line segment in terms of length and phases present (e.g. segment 1-2 is 2-mile long and has all phases a-b-c present while segment 2-3 has only phases a-c present). Refer to the diagram of a typical feeder in the textbook for reference. 2) Using ladder iterative technique, calculate the voltages at all buses for one feeder selected from your designed system. This calculation MUST show that the voltage at the Cal Poly Pomona ECE 5750 Distribution system and power quality – Instructor Dr. Ha Thu Le 1 end of the feeder is 0.95pu or a little higher under peak-load condition. Assume that the output voltage of the substation that serves the feeder is at the rated value. Specify the tolerance for iteration and use sweep matrices for all components present on the feeder. Adjust the system design if the requirement is not met. Write a Matlab m-file for this calculation then submit the code. Hint: Select the feeder that does not have a step- voltage regulator or induction motor to simplify the calculation. For line model, neglect the shunt admittance if you use overhead lines. Table 1 Distribution system parameters Transformer data Substation ratings, impedance Service transformer ID, ratings, impedance Line data Line ID, length, impedance, conductor type Load data Load ID, type, power, power factor 2. Simulation and analysis of distribution system Perform the following tasks: 1) Build your designed distribution system using Simscape Power Systems. Simulate the system and record all bus voltages to show that they are within the limits of +/-5% of the nominal values (i.e. 0.95-1.05 pu). Save and submit the project file. 2) Improving system load supply capability: Using simulation, maximize the total load that your system can supply. Add step-voltage regulators and/or capacitors to raise the system voltages. You must ensure that the system total load power factor is in the range of 0.85-0.95 lagging and the system bus voltages are within the limits. Record the system loads and voltages for Part 1 and 2 in Table 2. Table 2 Simulation results Original system Improved system Bus # Voltage Load Voltage Load pu kVA pu kVA . . . . . . . . . . . . . . . Total load Cal Poly Pomona ECE 5750 Distribution system and power quality – Instructor Dr. Ha Thu Le 2 Guide for simulation: 1) Building the grid: ADD a FEW COMPONENTS at a time. Then, run simulation to verify that the system works normally and fix errors if any. Proceed if the system performs as expected. 2) Save your project file EVERY TIME you change a parameter before running simulation. 3) Add only components from Simscape Power Systems (NOT from other Simscape folders) and general Simulink folder. 4) The simulation time is typically between 5-30 seconds to allow the transients to die out and the system to reach the steady state. Use ODE23tb or ODE23t as solver to reduce the time it takes the system to simulate. 5) Initialization of the system for simulation: To start the simulation in steady state, you must initialize machines (synchronous and/or asynchronous motor) for the desired load flow (a required initial state). Open the Powergui and select "Load Flow & Machine initialization". Click “Update Load Flow”, then close the dialog box and close the Powergui. Alternatively, click “Initial States Setting” then under “Force the initial electrical states” check “To Steady State”, click “Apply” then “Close”. Perform this step ONLY if you observe abnormal behavior in simulation after you add a component or make a change to the power system. Cal Poly Pomona ECE 5750 Distribution system and power quality – Instructor Dr. Ha Thu Le 3 The project must be completed using MATLAB/Simulink/Simscape Power Systems. Analytical hand calculation may be used for analyses and for presenting the results in the project report.