Contributions of Distributed Generation to Electric Transmission System

Abstract

Distributed generation (DG) refers to electricity generating plant that is connected to a distribution network rather than the transmission system. At present, small-scale DGs are mostly treated as ‘negative demand’ to the transmission system. However, if their contribution to transmission levels are fully understood and properly assessed, these generators can make into valuable assets to improve operational efficiency and substitute major infrastructure investment. This PhD research aims to addresses this challenge from three key aspects:1. On assessment methodologies, our current industrial practices to evaluate DG-to- transmission-contribution reveal inherent defects. The method given in the transmission system (SQSS) is not sufficient to reflect today’s dispersed generation technologies; while the method for the distribution system (P2/6) fails to reflect and discriminate between different characteristics of distribution networks that DGs are connected. Overcoming these drawbacks, enhanced frameworks to evaluate DG contribution have been developed in this research.2. On generator’s contribution, little attention has been paid to photovoltaic (PV) outputs characterization and their integration to the overall evaluation process. Neither SQSS nor P2/6 pays sufficient attantion to evaluating PV’s contribution to system. In this regard, an approach aiming at characterizing PV seasonal outputs is proposed. Integrating with the proposed frameworks, this part of the research completes the DG contribution evaluation architecture.3. On commercial arrangements, conventional business models largely rely on network investment to meet customer demand. Earning a fixed rate of return on invested capital, incumbent distribution network operator (DNO) businesses are encouraged to invest in network assets, very little has been done to support third party service providers for more efficient network development. In the third part of this research, alternative DNO business models and market mechanisms are proposed to further unlock the potential of DG, substantially increase the potential of their contributions to the transmission system.

Date of Award	26 Apr 2017
Original language	English
Awarding Institution	University of Bath
Supervisor	Furong Li (Supervisor) & Chris Budd (Supervisor)