SimPowerSystems 5.2

Emergency Diesel-Generator and Asynchronous Motor

This demonstration illustrates fault and islanding of an induction motor/diesel-generator system. The demo is composed of four short videos, 1-2 minutes each, and brief descriptions of some of the capabilities. The demos have an audio component, so please turn up the volume on your speakers if you choose to view them. The video segments run automatically, but you can set your own pace using the buttons at the bottom of the window.

The key products demonstrated are:

Contents

The System in Simulink

The power systems components of the system below have been implemented with SimPowerSystems, which works seamlessly with Simulink.

Click image to see enlarged view.

Some Conventions

• MW = MegaWatt - used to describe active power
• MVA = MegaVoltAmp - used to describe apparent power
• SM = Synchronous Machine
• ASM = Asynchronous Machine
• pu = Per Unit - See documentation for more information.

About the Circuit

A plant consisting of a resistive and motor (ASM) load is fed at 2.4 kV from a 25 kV distribution network through a 6 MVA 25/2 kV Wye-Delta transformer, and from an emergency synchronous generator/diesel engine unit (SM).

The 25 kV network is modeled by a simple R-L equivalent source (short-circuit level 1000 MVA) and a 5 MW load. The asynchronous motor is rated 2250 HP, 2.4 kV, and the synchronous machine is rated 3.125 MVA, 2.4 kV.

The diesel engine and governor system are modeled by a Simulink block (see tutorial in the User's Guide). Initially, the motor develops a mechanical power of 2000 HP (1.49 MW) and the diesel generator is on standby, providing no active power. The synchronous machine excitation system controls the 2400 V bus B2 voltage at 1 pu.

At t = 0.1 s, a three-phase to ground fault occurs on the 25 kV system, causing the 25kV circuit breaker to open at t = 0.2 s. The demonstration illustrates the mechanical and electrical transients following the fault and islanding of the motor/generator system.

Key Power System Components

This video analyzes the key components of the system. Once you finish viewing the video, close the video viewer window to return to this window.

Watch the video that analyzes the system. (1 minute, 55 seconds)

System Initialization

Let us initialize the system for simulation. We will use the POWERGUI graphical user interface to initialize the synchronous machine and the asynchronous motor for the desired load flow. Once you finish viewing the video, close the video viewer window to return to this window.

Watch the video of the system initialization. (1 minute, 15 seconds)

Simulating the System

The system is now ready to be simulated. Once you finish viewing the video, close the video viewer window to return to this window.

Watch the video of the simulation. (1 minute, 24 seconds)

Simulating with New Parameters

We are now going to increase the fault duration to 12 cycles. This is done by changing the opening time of the breaker to 0.3 second. We will then runanother simulation. Once you finish viewing the video, close the video viewer window to return to this window.

Watch the video of the second simulation. (1 minute, 11 seconds)