Protective Device Coordination

Minimize unnecessary outages while improving power system reliability.

A protective device coordination study ensures that your power system is both electrically coordinated and protected.

Protective devices such as relays, fuses, and circuit breakers sense the current flowing throughout the power system and interrupt the flow of power when a current larger than what is necessary for normal operating conditions is present. The characteristics of these devices can be graphically represented to verify that they will operate before equipment such as cables and transformers are exposed to and potentially damaged by the excessive current. In addition to protecting electrical equipment, these devices must also coordinate amongst themselves to ensure that only the faulted equipment is electrically isolated for the source (i.e. utility and on-site generation). If the power system is not coordinated, an interruption of power to more than just the affected equipment may occur. To perform this study, model numbers, ratings, and settings of the installed protective devices will need to be obtained. Information will also need to be gathered from conductors, transformers, and loads to verify they are adequately protected. It is crucial that routine maintenance be performed to ensure the protective devices continued to operate as intended.