Minilekce - Protecting electrical equipment

Protecting electrical equipment from the effects of overloads and short circuits is a very important area of the power industry. During the mini-lesson, students learned about the causes of overloads and short circuits, types of short circuits and the course of short circuit events and how to protect electrical equipment and operators from the consequences of these faults.

Properly designed protection of electrical equipment prevents major damage to electrical equipment, but also prevents electrocutions caused by faults in electrical equipment. The risk of faults must be taken into account in the design of equipment such as cables, lines, transformers, substations, switchboards and all elements and electrical apparatus used in the distribution system.

An important aspect of the subject is knowledge of the tripping characteristics of protective devices, i.e. fuses, circuit breakers and switches, and how they limit the short-circuit current. The impedance of the fault loop is also an important factor in fault occurrence and safe tripping. It is essential that the designer always assess the short-circuit immunity of the electrical equipment, the tripping capability of the apparatus and the characteristics of the wiring at the expected fault location. It is also necessary that when a fault occurs, the smallest possible part of the distribution equipment is always shut down with the fault.

The mini-lesson included a lively discussion between the students and the lecturer, who described various situations that can occur in the power grid and ways of solving and setting up protection. 

The cooperation between the school and the practitioner will enable pupils to understand the complexity of the issue of protecting electrical equipment and to correctly select and use fuses, circuit breakers, switches and other devices used to protect electrical equipment.

(Ing. Jiří Vastl)