Abstract:

This paper describes a technique to solve complex power system engineering problems through an inductive approach based on limit-case scenario analysis. The paper presents and discusses a variety of examples based on the experience of the author in teaching nonlinear system control and stability analysis to master and undergraduate students of electrical engineering programmes.

The author has more than one decade experience in teaching, in different institutions and countries, power systems modules, including power system modelling, control and stability analysis. A relevant aspect that has emerged as a common issue is the difficulty that students encounter when they have to find a reasonable solution of complex problems that depends on a large number of parameters and/or of variables. This kind of problems is common in power systems. Even small test networks, in fact, are typically composed of tens of different devices. In real-worlds networks the number of devices involved ranges from several hundreds to several thousands. Moreover, the equations that describes power system dynamics are nonlinear, which makes often inadequate a standard sensitivity analysis. The latter works well with linear systems, but due the nonlinearity of the equations that describe power systems, variational methods are insufficient or even misleading in certain cases.

The relatively simple and, as shown in the paper, quite effective analysis based on limit-case scenarios can partially overcome the difficulties above. This approach has been tested by the author in his modules “Power system Modelling and Control” taught since 2013 at the UCD School of Electric and Electronic Engineering.

This approach is utilized during lectures to clarify basic concepts of power system control and stability analysis. The main idea is to illustrate the behaviour of regulators and power system devices imposing limit-case values of key parameters and/or operating conditions. In the experience of the author such an approach is generally appreciated by the students and speed up the learning curve. The limit-case scenario approach also helps the students complete computer-based lab activities as it is aimed at defining sensible parameter values and reducing the need to solve not-meaningful simulations.

The final paper will provide the following contributions:
1. A discussion on the didactic challenges of teaching nonlinear dynamic systems to students of engineering modules. This discussion is particularly focused to electric power systems, but main concepts can be applied to any engineering area involving sets of nonlinear differential equations.
2. A variety of examples that illustrate the effectiveness of using limit-case scenarios to improve the understanding of the dynamic response of principal power system devices as well as primary regulation. These examples are also presented during the lectures, hence, students' feedback is also duly discussed where relevant.
3. An overview of the lab activities that are proposed for the module “Power System Modelling and Control” offered by the author at UCD as part of the ME Programme in Electric Energy Systems, as well as a discussion of how some questions that the student have to answer during such lab activities can be efficiently addressed through the limit-case scenario approach.

Keywords:

Electrical energy systems, electrical engineering education, limit-case analysis, computer-based laboratory.