DIRECT & INDIRECT METHODS OF ENERGY AUDIT
I) Direct Method: In this method, losses are found on the basis of difference of units sent out and received at the end of each element in the power system. The main advantage is that it is straight forward and simple. The major constraints are that it calls for metering of very high class of accuracy and the difficulty, in simultaneous reading of meters. Due to employing CT & PT of very high ratios the multiplying factors are very large and any small variation will result in large discrepancy.
II) Indirect Method: The losses are determined by simulation of the network. With the advent of powerful mini and micro computers at affordable prices and good models for simulation of T&D networks this is more popular and practical. Even in this system, metering at critical points in the system for operating parameters such as power factor, coincident fact, or load factor, loss factor and hourly load data is required for use in simulation.
Ref : APED Manual Volume I, Page no 149, Para no 227
