ELECTRICAL NETWORK
Electrical power networks are due to their very nature highly exposed to transient overvoltages both as a result of conduction and induction phenomena. Also do permanent overvoltages (a.k.a. TOV) pose a thread to equipment connected to electrical power networks.
Overvoltages in electrical networks
Electrical power networks typically consist of a large distribution infrastructure and are therefore highly exposed to induction and conduction of transient overvoltages. These overvoltages are mainly originated by atmospheric phenomena. Through direct or indirect contact, do lightning strikes cause voltage peaks of thousands of volts (kV). These peaks propagate along and throughout the network, potentially damaging electrical and electronic devices.
Besides transient overvoltages, can also temporary overvoltages take place in electrical networks provided that the distribution sustem shares the 3-phase with a neutral wire (3P+N). Typically, a loss of the neutral wire causes an imbalance in the distribution system and compensation between phases is therfore no longer assured. This leads to a temporary overvoltage which can cause anything from early aging to setting in fire the installation or immediately destroying the devices.
Temporary Overvoltages
Peaks of hundred of volts lasting for an indefinite period of time. They are caused by the imbalance between phases, which is in turn caused by a loss/cut of the neutral wire.
Transient Overvoltages
Very high peaks (kV) of a very short duration (microseconds). They are caused by lightning strikes and network switching of power utilities.
