A SURVEY OF SYSTEMS TO INTEGRATE DISTRIBUTED ENERGY RESOURCES AND ENERGY STORAGE ON THE UTILITY GRID

Joseph A. Carr, Juan Carlos Balda, H. Alan Mantooth

National Center for Reliable Electric Power Transmission

University of Arkansas

Simple Direct Grid Connection

PEI For Doubly Fed Induction Generator

Voltage Step-Up

Most DER’s Requires boost or step-up transformers

Transformers provide isolation required by the National Electric Code

Multiple Connections

DER’s require arrays of individual modules Array limited to weakest module

Separate Grid Connections

Advantages Optimize each PEI to the DER Each PEI is simple

Disadvantages Grid Power Line Use Increased power electronics

Microgrid Connections

Consolidate DERs on single bus 3 types:

Line Frequency DC Bus High Frequency AC

Line Frequency Microgrid

DC Microgrid

High Frequency AC Microgrid

Multiport Converters

Common Bus like Microgrids No Direct Local Load Connection

Regulation of Bus not needed Converters do not have to match bus

specifications

Standalone Multiport

Modular Multiport

High Frequency Multiport

Modular HF Multiport

Summary