The equivalent hours loss factor revisited (power systems)

Abstract

Specific portions of electric systems experience losses, which are a function of load. In these cases utility engineers have historically used one of two equations to determine the equivalent-hours loss factor which can be used to determine the energy losses when the load factor is known. One of these two equations determines the equivalent-hours loss factor as a function of load factor and load factor squared. This equation was developed by F.H. Buller and C.A. Woodrow in 1928 with a recommended value of 0.3 for the constant coefficient term (the coefficient of the load factor term). The second equation determines the equivalent hours loss factor as a function of the load factor raised to a power. The value for the exponent commonly used in industry practice is 1.6. The authors argue that the values of 0.3 for the constant coefficient and 1.6 for the exponent no longer appear to be appropriate. In fact, analysis of a wide range of utility annual EEI-formatted load data sets results in a value of 0.08 for the constant coefficient and 1.912 for the exponent. Equations with revised coefficients are calculated and verified.