IEEE Std 798:2006 pdf free download

IEEE Std 798:2006 pdf free download.IEEE Standard for Calculating the current-Temperature of
Bare Overhead Conductors.
The primary application of this standard is anticipated to he the calculation of steady-state and transient thermal ratings and conductor temperatures under constant weather conditions. Given the widespread availability of desktop personal computers, the calculation method specified avoids certain simplifications that might be advisable where the speed or complexity of calculations is important.
In Davis [59], the heat balance equation is expressed as a biquadratic equation that can be solved to give the conductor temperature directly. In Black and Rehberg [115] and Wong. et al. 111301, the radiation term is linearized and the resulting approximate linearized heat balance equation is solved using standard methods of linear differential equations. In Foss [[514]. a somewhat more precise linearized radiation term is used to reduce the number of iterations required. These methods are computationally faster than the iterative method described in this standard; however, the algebraic expressions are more complex.
3.1 Steady-state calculations
3.1.1 Steady-state thermal rating
For a bare stranded conductor, if the conductor temperature (T) and the steady-state weather parameters (Vs, T, etc.) arc known, the heal losses due to convection and radiation (q and q). the solar heat gain (qj, and the conductor rcsistance R( T) can be calculated by the formulas of 3.4. The corresponding conductor current (1) that produced this conductor temperature under these weather conditions can be found from the steady-state heat balance [Equation (I b) of 3.4.1]. While this calculation can be done for any conductor temperature and any weather conditions, a maximum allowable conductor teniperature (e.g., 75 °C to 150 °C) and “conservative” weather conditions (e.g., 0.6 ms to 1,2 ni/s wind speed, 30 °C to 45 °C summer ambient) are often used to calculate a steady-state thermal rating for the conductor.
3.1.2 Steady-state conductor temperature
Since the radiation and convection heat loss rates are not linearly dependent on the conductor temperature, the heat balance equation [Equation (I b) of 3.4.11 is solved for conductor temperature in terms of the current and weather variables by a process of iteration that is, given a conductor current.