Standardizing Performance Metrics for Building-Level Electrical Distribution Systems

Moazzam Nazir,Cameron Wierzbanowski,Avijit Saha,Willy Bernal Heredia,Daniel Gerber,Omkar Ghatpande

doi:10.3390/en15010136

Moazzam Nazir, Cameron Wierzbanowski + Show 4 more

Open Access

https://doi.org/10.3390/en15010136

Copy DOI

Abstract

Building-level electrical distribution systems comprise a myriad of current-carrying equipment, conversion devices, and protection devices that deliver power from the utility or local distributed energy resources to end-use building loads. Electric power has traditionally been generated, transmitted, and distributed in alternating current (AC). However, the last decade has seen a significant increase in the integration of native direct current (DC) equipment that has elevated the importance of DC distribution systems. Numerous studies have comparatively examined the performance of various electrical distribution systems in buildings but have failed to achieve uniform conclusions, primarily because of a lack of consistent and analogous performance evaluation methods. This paper aims to fill this gap by providing a standard set of metrics and measurement boundaries to consistently evaluate the performance of AC, DC, or hybrid AC/DC electrical distribution systems. The efficacy of the proposed approach is evaluated on a representative medium-sized commercial office building model with AC distribution and an equivalent hybrid AC/DC and DC distribution model, wherein the AC distribution model is concluded to be the most efficient. The simulation results show variation in computed metrics with different selected boundaries that verify the effectiveness of the proposed approach in ensuring consistent computation of the performance of building-level electrical distribution systems. This paper provides an initial set of guidelines for building energy system stakeholders to adopt appropriate solutions, thus leading to more efficient energy systems.

Highlights

Due to significant advancements in power electronic converters, which enabled efficient voltage transformation, allowing direct current (DC) systems to become comparable to transformers in alternating current (AC) systems, DC has once again emerged as a compelling option for transmission and distribution purposes
The proposed metrics and associated computation strategies presented in the previous sections provide the framework for building a research and design community to perform a detailed comparative analysis of AC, DC, and hybrid AC/DC systems
Work This paper motivates the need for a standard system of metrics and methods to describe, quantify, and compare the performance of electrical distribution systems across building types, applications, and sizes

Summary

Introduction

Robust measures are being adopted to decrease building emissions and energy utilization while increasing on-site generation and efficiency [2]. DC systems have fewer conversion stages, which can significantly increase energy efficiency; a single conversion stage can exhibit losses ranging from 5% to 14% [5]. They pose less danger than AC at similar voltage levels. DC systems do not suffer from synchronization challenges, and they can provide better power quality and achieve higher reliability They can incorporate static storage and facilitate the integration of distributed energy resources (DERs) (mostly DC-native) [5,6]. As a result of these advantages and the increased adoption of miscellaneous electric loads in buildings that operate internally on DC, building-level DC distribution systems have emerged as a promising alternative to AC distribution

Objectives

Results

Discussion

Conclusion