DESIGN OF A LABORATORY MINI HYDROELECTRIC PLANT FOR EDUCATIONAL PURPOSES

A laboratory test rig has been designed for learning of Electrical Engineering students. The prototype designed simulates a hydroelectric plant. Different electronics and electromechanical devices have been used to simulate every module that constitutes the hydroelectric plant. This laboratory prototype has been chosen because of its importance on learning of Electrical Engineering students, since it is a good example in which the students can learn how the electric energy is generated. Various aspects have been considered in design:

- Competence based education and training. Laboratory practices done with the mini hydroelectric plant must help to students to acquire some of the general competences that an Electrical Engineering Graduate must acquire in the European Space of Higher Education. This laboratory test rig is an excellent teaching material for students learning and a good implementation of a hydroelectric plant prototype.

- Security. The laboratory test rig has been designed to work under low power and complying with safety regulations in teaching laboratories to avoid personal and material damages.

- Multi-disciplinary laboratory work. Because of the importance of the topic treated (hydroelectric plant) for an Electrical Engineering student, the prototype proposed in this work can be used in several subjects of an Electrical Engineering Degree, for example: electric technology; electronics; electric machines; automatic control; power electronics; electric plants; conventional power systems; electronics instrumentation. In addition it can also be an important supporting teaching material for teachers.

- Modular laboratory test rig. The prototype has been divided into modules visibly independent. In this way, the students can identify easily every part of a hydroelectric plant as well as to work with every module independently of others. The laboratory test rig can be divided into two main parts:

· The plant system simulates the complex physical system of a hydroelectric plant. An electric fan, commanded by a control system, generates a volume of air (it simulates a volume of water) that cool down a thermo-sensitive resistor. The thermo-sensitive resistor signal controls the voltage applied to a group motor-generator (it simulates a group turbine-generator of a hydroelectric plant) which generates a particular level of energy, dissipated in a resistor (it simulates the consumption point). One of the objectives of this prototype is that the above subsystems can be analyzed independently by students.
· The control system must satisfy three purposes:
1) to monitor every electric signal of the plant in order to know the internal state of that at any time;
2) to control the general performance of the plant according to instructions given by the user;
3) to control independently the performance of each module of the plant. In this way, different modules can be used for different subjects.

- Graphical user interface. The laboratory test rig has been designed in order that students are able to monitor and control each module of that from a computer by means of a graphical user interface programmed with a visual programming language (LabView). The students hence have an intuitive knowledge of the mini hydroelectric plant and a better understanding of the complete system performance.