SPDC Terms beginning with E

Terms and definitions extracted from current SPDC published documents
Click one of the capital letters above to advance the page to terms beginning with that letter.
effectively grounded system

A system grounded through a sufficiently low impedance such that for all system conditions the ratio of zero-sequence reactance to positive-sequence reactance (X0/X1) is positive and less than 3, and the ratio of zero-sequence resistance to positive-sequence reactance (R0/X1) is positive and less than 1.

electrical environment

The totality of conducted electrical phenomena existing at a given location.
NOTE: These phenomena become disturbances only if they degrade the performance of equipment.

electrical unit

Portion of an arrester in which each end of the unit is terminated with an electrode which is exposed to the external environment.

energy deposition

The time integral of the power dissipated in a clamping?type surge protective device (SPD) during a current surge of a specified waveform.

external insulation

The air insulation and the exposed surfaces of solid insulation of equipment, which are both subject to dielectric stresses and to the effects of atmospheric and other external conditions such as contamination, humidity, vermin, etc.