English to Spanish Tech/Engineering Electronics / Elect Eng Relay for smart grids

Hello! I'm translating some technical data about equipment for protection of smart grids. These terms are whithin a table called "Voltage presence - main settings" and one of the items is "V live value". Others are: "V live time" and "V dead value". I'm pretty sure that the V stands for "voltage", so I would translate this as "Valor con tensión" o "valor presencia de tensión" but I would like to know your opinion on this. Thank you.