Estimating LV secondary voltage drop using AMI data for improved distribution management

Abstract

Low voltage (LV) wiring and distribution transformers are an important part of the system delivering electricity to the customer, but information about the performance, and even about the lengths and impedances, of service-level components has been limited in the past. Now that increased pressures are being put on the grid by distributed generation and new loads, and the system is being held to closer tolerances through programs like conservation voltage reduction (CVR), it is becoming more important to understand the voltage drops at the LV service level. However, these voltage drops are rarely measured and reported on in the literature, particularly for US systems. This paper discusses three methods for measuring for LV secondary drop, using newly available measurements of customer voltage by advanced metering infrastructure (AMI) alongside other data. Based on AMI measurments and other data from three US utilities, it was found that while most secondary drops are within the ranges typically cited by utilities, there are a few spots with larger voltage drops that could be a problem given future CVR programs or the installation of additional load or PV.