Method for determining electrical energy consumption

Abstract

A method of operating a meter to perform the steps of generating a measure of real energy consumed, generating a measure of reactive energy consumed, and generating, from the real energy and reactive energy measures, a measure of apparent energy consumed. In one embodiment, the real energy and reactive energy measures are provided as integer quantity inputs. Particularly, assume S=kVAh, P=kWh, Q=kVARh, and R=Residue. Respective registers store values of P, [2P+1], Q, [2Q+1], and the sum [P.sup.2 +Q.sup.2 ]. Initially, the P, Q, and [P.sup.2 +Q.sup.2 ] registers are set to zero, while the [2P+1] and [2Q+1] registers are initialized to 1. At the arrival of a P pulse, the value in the [2P +1] register is added to the [P.sup.2 +Q.sup.2 ] register, then the P register is incremented by 1 and the [2P+1] register is incremented by 2. Exactly the same steps are carried out subsequent to receipt of a Q pulse. A set of registers also is used to store the S and [2S+1] data, and generation of the S pulses is determined as follows. After arrival of either a P or Q pulse, a trial subtraction of [2S+1] is made from the [P.sup.2 +Q.sup.2 ] register. If the subtraction does not cause an underflow, an S pulse is generated, the S register is incremented by 1, and the [2S+1] register is incremented by 2. If the subtraction causes an underflow, the [P.sup.2 +Q.sup.2 ] register is reset to its previous value, the other registers are not incremented, and no S pulse is generated.