The development of techniques and companies is leading to an increase in performance and a decrease in the cost of products. This double development causes an increase in the sensitivity of technical systems, both from the point of view of the level of disturbing phenomena and their type. This is particularly important in the domains of electricity, electronics, computer science and telecommunications. In these fields, the balance between the levels of emission and the levels of immunity of products are within the framework of rules called electromagnetic compatibility (EMC). The electricity supplied by public distribution networks is used both as a primary source of energy and as an auxiliary source for efficient control circuits. Therefore, co-ordination between the different usages of electricity is necessary. The above-mentioned electromagnetic compatibility is then called power quality. The paper discusses three aspects of power system EMC as follows: quality of supply due to energy saving loads and decentralised generation; management of the electric and magnetic fields created by the networks; and EMC standards