1. A system for characterizing non-technical losses in an electric utility power distribution inventory zone, the inventory zone comprising a plurality of nodes including at least one metered distribution node and at least two metered consumer nodes, the system comprising: a data store comprising a non-transitory computer readable medium containing inventory zone load profile data and consumer load profile data for each of the consumer nodes; and a data processor communicatively coupled to the data store and configured to: obtain the inventory zone load profile data from the data store; obtain the consumer load profile data for each of the consumer nodes from the data store; determine bypass diversion factors for the consumer nodes and aggregate tap loads for the inventory zone that: solve a system of load balance equations for the inventory zone having known values corresponding to the inventory zone load profile data and to the consumer load profile data and having slack variables representing the aggregate tap loads, in which the known values corresponding to the consumer load profile data are scaled by the bypass diversion factors; and minimize an objective function whose value is positively related to the sum of the slack variables representing the aggregate tap loads; and generate a record in a non-transitory medium indicating the determined bypass diversion factors and aggregate tap loads.