INTERACTION MODELLING AND SAFETY IN THE ELECTRICITY INDUSTRY
Maria F.Q.Vieira Turnell
Alexandre Scaico
LIHM –DEE - UFCG
Campina Grande,Brazil
fatima@dee.ufcg.edu.br
scaico@dee.ufcg.edu.br
Charles Santoni
LSIS Univ. D’Aix-Marseille III
Marseille, France
charles.santoni@lsis.org Fernando A. Q.Vieira
Madson R. B.Pereira
DOMO-DOS-SOC-DO and SLOG-DO CHESF, Brazil
fvieira,@chesf.gov.br
madsonrp@chesf.gov.br
Key words— Human Interface Design, Industrial safety, Process supervision
ABSTRACT
In this paper we describe a statechart model of the human interaction which takes place in an electricity substation. This model was developed to be used as a support tool in the process of incident analysis and interface design. The model concerns the human interface components typically used to perform the task of substation supervision and control. The paper discusses how the model can be used, together with a description of an incident scenario, to help designers understand the design factors which might contribute to it. Finally, it suggests how to apply this knowledge in the process of human interface design in order to improve safety standards related to industrial systems operation.
1. INTRODUCTION
Quality standards, particularly in the automated industry are continually rising, leading into more restrictive work practices. These standards are directly related to safe and efficient operation of the systems involved in the industrial process. Knowing that many incidents are the result of human errors, the analysis and understanding of the context in which they occur can contribute to review the human interface component of these systems.
This paper proposes a formal model to support the construction of an incident scenario simulator which is to be used in the activity of incident analysis. The objective of this incident simulation is to help specialists and the technical personnel involved in the incident understand the scenarios in which these occur. The simulation consists in executing a formal model of the interaction between the operator and the industrial system’s human interface, based on a scenario model. The simulation will result in playing back the sequence of actions and system’s state before and at the time of the incident. The scenarios to be simulated result from the analysis of the industry’s incidents reports, relative to incidents which resulted from human errors. (Turnell at al. 2004, Guerrero et al. 2004). The analysis of these reports is based on the knowledge acquisition method KOD (Vogel 1988).
The interaction model presented in this paper is that of a substation in an electric power distribution system. More specifically the model represents the interactive components typically found in this work environment, such as switches and light indicators in control panels, used by the operators in order to perform their task. This interaction model was built using the formalism statechart (Harel 1987, Harel et al. 1987).
Although the use of simulators are a common practice in the academia as well as in the industry, the proposed approach consists in building the simulator based upon a model of the incident scenarios, which results from the analysis of the corpus of the industry’s incident reports
This paper is organized in 8 sections. Section 2 introduces the method for user interface conception (MCIE) adopted in this work and to which the interaction model will be integrated. Section 3 presents this study’s context of application, i.e. the operation of a substation in an electricity distribution network. Section 4 presents the user model built to represent the interactions between the substation operator and the substation’s interface. Section 5 presents the model of the substation’s user interface. Section 6 presents the substation interaction components. Section 7 describes an incident scenario and discusses the preliminary results from its simulation. Finally, section 8 presents the conclusions and proposes future directions for this work
2. MODELLING USER INTERFACES
The volume of information presented to an industrial plant operator is usually high; the task imposes hard deadlines and navigation restrictions resulting in high cognitive loads. On the other hand the operator has to react to events and complete a task taking into account restrictive deadlines and safety conditions. Thus, the conception of the user interface component plays an important role in the safety of the system operation.
The conception of ergonomic human interfaces for industrial applications is the focus of the research at the LIHM at UFCG, as well as at LSIS (Santoni 1997). The

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