Conservation Voltage Reduction and Volt-VAR Optimization: Measurement and Verification Benchmarking

Abstract

The ongoing efforts in grid modernization, which is accompanied by upgrading distribution grids through employment of advanced distribution grid technologies, further provide the necessary tools to employ Conservation Voltage Reduction (CVR) and Volt-VAR Optimization (VVO) programs and ensure that the system is operating continuously at an optimized voltage. This paper provides an overview of CVR/VVO deployments by several electric utilities within the U.S. The paper looks at three major areas: (i) type of the initiative, including pilot, plan, program, study, and test case; (ii) year(s) of the application; and (iii) methodology used for CVR factor assessment. When available, a more detailed discussion on the initiative is provided. Based on the studied cases, it is concluded that majority of utilities use either a regression-based or a comparison-based method. The day-on/day-off approach is common within both methods in which CVR is applied every other day to generate CVR-on and CVR-off data that can be used for comparison and model fitting.

Sensitivity Analyses of CVR Measurement and Verification Methodologies to Data Availability and Quality

“…Constant CVR factor is considered to be 0.8 in this study. The constant CVR factor of 0.8 is obtained based on the M&V benchmarking studies performed in [15] and the fact that numerous utilities calculate a similar or close CVR factor to this value.…”

“…In this paper, the comparison-based, regression-based, and constant CVR factor methodologies are considered. Different utilities have widely used these methodologies in pilot and program level studies [11], [15]. These methodologies are explained below.…”

“…Several utilities consider a constant CVR factor as their system-wide or feeder-wide CVR factor. Based on this constant CVR factor, they accordingly obtain baseline energy and energy savings [15]. A constant or deemed CVR factor can be chosen based on the studies conducted on a set of feeders and their simple or load-weighted average.…”

“…A lack of defined guidelines on selecting the CVR M&V methodology is another major challenge in CVR deployment, however there are existing standardization efforts at IEEE. Based on our previous benchmarking studies in [15], utilities primarily leverage three CVR M&V methodologies as discussed in the following:  Comparison-based methods: The comparison-based methods leverage operational data under CVR (treatment) and non-CVR (control) conditions and accordingly determine the CVR factor by comparing these two cases [16]. There are two general categories for comparison-based methods: correlated-feeder and correlated-weather.…”

Flexibility Services Provision by Frequency-Dependent Control of On-Load Tap-Changer and Distributed Energy Resources

“…Compatibility of CVR schemes with other distribution network control schemes, such as Volt-VAr control and optimisation [19], is also very important. Different types of DER units have increasingly been connected to distribution networks and they also have an effect on the operation of the CVR schemes.…”