Electrical Engineering Virtual Electric Machine & Power Labs

Simscape Labs and Lab Assignments for Three-Phase Systems, Transformers, DC Series and Shunt Motors, Synchronous Generator

Introduction

The modern Electric Power System is a modern engineering marvel, providing instantaneous power at precise voltage and frequency requirements to a wide range of industrial, commercial, and private customers. The electric power system includes generation, transmission, and distribution systems. Transmission lines as the connecting links between these systems. Three-phase to single phase circuits transports the electric power from generation to the end-user.

The Electric Power course introduces the engineering student to the concepts needed for an understanding of the electric power system. The topics normally covered are:

• Three-Phase circuits and power systems
• Single and Three-Phase Transformers
• DC Motors and Generators
• Synchronous Motors and Generators
• Induction Motors

The power course objective is to provide an understanding of the electric machine physical construction, fundamental laws governing their operation, external characteristics, and the relation between performance to equivalent circuit models.

The power course also has an attending lab where the engineering student gains experience and intuition in the actual operation of the electric machines and systems. The typical lab requires the student to connect the power circuit, run and record data for differing parameters, reduce the data and perform calculations, and then write a lab report.

This file exchange contains eight virtual power labs with accompanying lab assignments. The lab and lab assignment are to mimic the actual hardware lab operation and tasks required. Each lab is designed to allow the student to actively investigate what happens as they vary parameters. Each lab allows the student to vary certain parameters and see the resulting data.

The lab assignments provide lab objectives, model description, experimental tasks, and analytical tasks.

Virtual Power Lab Summaries

The following summarizes the virtual labs description, experimental and analytical tasks:

Three-Phase Circuit Lab

Description: Balanced three-phase source, transmission line, and WYE/Delta loads

Experimental Task: Run model for range of load impedances with WYE and Delta individually and combined WYE/Delta varying transmission line length

Analytical Task: Use equivalent circuit models to verify model performance, calculate circuit’s efficiency and compare power delivered to the WYE and Delta loads

Three-Phase Power Lab

Description: Balanced WYE Source with Step-up and step-down transformers linked three-wire transmission line and Series and Parallel RLC Loads

Experimental Tasks: Run model with individual Series RLC Load and Parallel RLC Load under real and complex power loading

Analytical Tasks: Use three-phase complex power relationships to verify the voltages, currents, and power predicted in the model

Single Phase Transformer Lab

Description: Single phase AC source, non-ideal transformer, and load impedance with circuit breakers to short and open circuit the transformer

Experimental Tasks: Run model for range of real, reactive, and complex load impedances and perform the Open and Short Tests

Analytical Tasks: Calculate efficiency and voltage regulation for each loading, Use the Open/Short Test results to develop the equivalent circuit parameters, use the equivalent circuit model to verify the model’s performance

Three-Phase Transformer Lab

Description: Balance WYE-connected three-phase source, three-phase non-ideal transformer, and WYE-connected parallel RLC Load

Experimental Tasks: Run model using WYE-Connected and Delta-connected parallel RLC Load for real, reactive, and complex loads, run model with WYE-real load, for WYE-WYE, Delta-Delta, WYE-Delta, and Delta-WYE transformer connections, repeat using Delta load

Analytical Tasks: Verify the model’s performance using hand calculations and transformer equivalent circuit model, discuss how the various transformers connections impact efficient and total delivered power

DC Series Motor Lab

Description: 10 HP / 1750 RPM DC series motor with adjustable DC Terminal Voltage and Mechanical Load Torque

Experimental Tasks: Adjust the DC voltage to achieve 10 HP output at 1750 RPM, then vary mechanical load torque, adjust DC voltage to values above and below initial DC voltage while varying the load torque

Analytical Tasks: Plot the torque-speed, torque-armature current, and power-speed curve, use the motor’s equivalent circuit model to verify the model’s performance, and compare curves to the curves developed for the DC Shunt Motor

DC Shunt Motor Lab

Description: 10 HP / 1750 RPM DC shunt motor with adjustable DC Terminal Voltage and Mechanical Load Torque

Experimental Tasks: Adjust the DC voltage to achieve 10 HP output at 1750 RPM, then vary mechanical load torque, adjust DC voltage to values above and below initial DC voltage while varying the load torque

Analytical Tasks: Plot the torque-speed, torque-armature current, and power-speed curve, use the motor’s equivalent circuit model to verify the model’s performance, and compare curves to the curves developed for the DC Series Motor

Synchronous Generator Lab

Description: WYE-Connected, 10.2 kVA, 460 V rms, 60 Hz, 1800 RPM generator with adjustable DC Field voltage and generator speed, three-phase parallel RLC load impedance, and three-phase circuit breakers

Experimental Tasks: Perform the Open and Short Circuit Tests, run the model for inductive complex load and capacitive complex loads

Analytical Tasks: Plot the Open and Short Circuit characteristics, determine the synchronous reactance, use the generator’s equivalent circuit and power flow models to verify the model’s performance

Synchronous Motor Lab

Description: WYE-connected, 10.2 kVA, 762 V rms, 60 Hz, 1800 RPM, salient-pole rotor motor with balanced three-phase source, adjustable DC Field voltage and mechanical load

Experimental Tasks: Set constant DC Field Voltage and vary mechanical load, recording induced torque, armature current, and torque angle, set constant mechanical load

Analytical Tasks: Plot phasor diagrams representing three load conditions to determine the impact of load changes, Plot phasor diagrams for a constant mechanical load with varying field currents to determine the impact of field current changes, plot the motor’s V-curve and Power Factor versus field current

Note

1. The Three-Phase Power Lab will error if a Delta connection isolates the sensor between ungrounded networks. Use the grounded WYE connection for the transformers and loads
2. The DC Motor labs can be run beyond the motor stall torque resulting in negative power and rotational speed.
3. The motor and generator models do not account for friction and windage losses

Acknowledgments

Acknowledge the contributions of Chad Allie, MathWorks, Britney Baxter, TU ECE graduate, and Thomas Reid, TU ECE Graduate Student