Advanced modeling techniques for dynamic feeder rating systems

Introducing Mutual Heating Effects in the Ladder-Type Soil Model for the Dynamic Thermal Rating of Underground Cables

“…1(a), which represent the losses in the conductor, insulation, and sheath, respectively. Thus, these losses circulate through all the resistances in the soil model and represent the first term on the right-hand in (8).…”

“…Better modeling, more advanced grid infrastructure, and faster computation capabilities in the context of smart grid operations lead to the necessity of determining the real-time ratings of power cables [8], [12]. Also, current research shows that accurate real temperature transients can be used to determine the useful life of cables in service with dedicated life models [15], [16].…”

“…This would certainly avoid dangerous situations affecting the stability and resiliency of the power grid. The model of this paper can be easily integrated into the available software and models for Real Time Thermal Rating systems that benefit of state space forms in order to use available parameter estimation techniques or recursive filtering [8], [17], [23].…”

Managing cable thermal stress through predictive ratings

“…Furthermore the experimentally based equation is over-simplified and can't satisfy all cable geometries and arrangements. Morgan [6] has shown that exponent ¼ in (2) and heat transfer coefficient h in (3) varies with the temperature rise of the cable surface. This is because the larger temperature rise of the cable surface will cause further reduction in air density, which will lead to greater air velocity.…”

“…Given the relatively short durations of peak loads and the comparatively long thermal time constants of high voltage cables, it is often possible to load cables beyond their continuous current rating without the cable exceeding its operating temperature limit. Many utilities are now beginning to use dynamic ratings as a method of using this additional capacity safely [1,2,3], however this data is not available at the day ahead planning stage, which would be very valuable to network operators.…”