Publications

Results 126–142 of 142
Skip to search filters

Formulating a simplified equivalent representation of distribution circuits for PV impact studies

Broderick, Robert J.

With an increasing number of Distributed Generation (DG) being connected on the distribution system, a method for simplifying the complexity of the distribution system to an equivalent representation of the feeder is advantageous for streamlining the interconnection study process. The general characteristics of the system can be retained while reducing the modeling effort required. This report presents a method of simplifying feeders to only specified buses-of-interest. These buses-of-interest can be potential PV interconnection locations or buses where engineers want to verify a certain power quality. The equations and methodology are presented with mathematical proofs of the equivalence of the circuit reduction method. An example 15-bus feeder is shown with the parameters and intermediate example reduction steps to simplify the circuit to 4 buses. The reduced feeder is simulated using PowerWorld Simulator to validate that those buses operate with the same characteristics as the original circuit. Validation of the method is also performed for snapshot and time-series simulations with variable load and solar energy output data to validate the equivalent performance of the reduced circuit with the interconnection of PV.

More Details
TYPE SAND Report YEAR 2013
OSTIDOI

Time series power flow analysis for distribution connected PV generation

Ellis, Abraham E.; Quiroz, Jimmy E.; Reno, Matthew J.; Broderick, Robert J.

Distributed photovoltaic (PV) projects must go through an interconnection study process before connecting to the distribution grid. These studies are intended to identify the likely impacts and mitigation alternatives. In the majority of the cases, system impacts can be ruled out or mitigation can be identified without an involved study, through a screening process or a simple supplemental review study. For some proposed projects, expensive and time-consuming interconnection studies are required. The challenges to performing the studies are twofold. First, every study scenario is potentially unique, as the studies are often highly specific to the amount of PV generation capacity that varies greatly from feeder to feeder and is often unevenly distributed along the same feeder. This can cause location-specific impacts and mitigations. The second challenge is the inherent variability in PV power output which can interact with feeder operation in complex ways, by affecting the operation of voltage regulation and protection devices. The typical simulation tools and methods in use today for distribution system planning are often not adequate to accurately assess these potential impacts. This report demonstrates how quasi-static time series (QSTS) simulation and high time-resolution data can be used to assess the potential impacts in a more comprehensive manner. The QSTS simulations are applied to a set of sample feeders with high PV deployment to illustrate the usefulness of the approach. The report describes methods that can help determine how PV affects distribution system operations. The simulation results are focused on enhancing the understanding of the underlying technical issues. The examples also highlight the steps needed to perform QSTS simulation and describe the data needed to drive the simulations. The goal of this report is to make the methodology of time series power flow analysis readily accessible to utilities and others responsible for evaluating potential PV impacts.

More Details
TYPE SAND Report YEAR 2013
OSTIDOI

Evaluation of alternatives to the FERC SGIP screens for PV interconnection studies

Conference Record of the IEEE Photovoltaic Specialists Conference

Broderick, Robert J.; Ellis, Abraham E.

Existing screening procedures contained in state and federal interconnection rules are designed to balance the need for efficiency and technical rigor for all Distributed Generation (DG). The interconnection of DG that pose no risk of system impacts based on the screens can be expedited without the need for further studies. While the interconnection screening procedures have served the industry well, they also need to evolve in order to remain relevant with respect to evolving standards, technology, and practical experience. This is particularly important considering the large and increasing volume of DG applications, particularly photovoltaic (PV) generation. This paper discusses the application of two screens from the point of view of PV: the 15% penetration on line sections and the 20 kW aggregate capacity screen for single-phase secondary circuits. We discuss extensions to the existing interconnection screens that allow for a more rigorous upfront technical evaluation to identify potential system impacts, based on the characteristics of PV generation. More effective and efficient screens will allow utilities to focus the interconnection study effort for PV systems on the cases most likely to impact the electric distribution system and avoid unnecessary interconnection study costs and delays. © 2012 IEEE.

More Details
TYPE Conference YEAR 2012
ScopusOSTI
Results 126–142 of 142
Results 126–142 of 142