Energization of long HVAC cables in parallel – Analysis and estimation formulas

The installation of long HVAC cables has recently become more common and it will likely increase during the next years. Consequently, the energization of long HVAC cables in parallel is also a more common condition.The energization of HVAC cables in parallel resembles the energization of capacitor banks in parallel and high inrush currents are associated to both energization phenomena.The existing IEEE standard C37.012-2005 for capacitive switching proposes a formula that can be used to estimate the peak magnitude and frequency of the inrush current. However, for sake of simplicity, the formula has several simplifications and it does not always provide accurate results. This paper proposes a new formula that can be used for the estimation of these two quantities for two HVAC cables in parallel.

► A new method that estimates the inrush frequency associated to the energization of cables in parallel.
► The method can be applied without using simulation software.
► It is based in the same premises of the standard method, but has a higher accuracy.