Distributed generation and its impact on power grids and microgrids protection
The National Institute of Standards and Technology, NIST, is assigned by the US Department of Energy, DoE, to drive Smart Grid developments and harmonization efforts in the power industry. Distributed Generation has been identified as one of the important areas for the Smart Grid developments. Multiple generation sources, bi-directional power flow, power flow time co-ordination and management bring significant benefits and challenges for the existing and emerging power grids and microgrids. In particular, the effect of distributed generation on protection concepts and approaches needs to be understood, and accounted for. This paper describes distributed generation concepts, applications and scenarios. Benefits and challenges are discussed and analyzed on a number of real life examples. Special considerations are provided on ensuring security and dependability, as well as on protection parameterization and coordination.
Impacts of distributed generation on low-voltage distribution network protection
This paper reports work of a MEng student final year project, which looks in detail at the impacts that distributed generation can have on existing low-voltage distribution network protection systems. After a review of up-to-date protection issues, this paper will investigate several key issues that face distributed generation connections when it comes to network protection systems. These issues include, the blinding of protection systems, failure to automatically reclose, unintentional islanding, loss of mains power and the false tripping of feeders. Each of these problems impacts on protection systems in its own way. This study aims to review and investigate these problems via simulation demonstrations on one representative network to recommend solutions to practices.
Integrated substation systems-harmonizing primary equipment with control and protection systems
Dynamic changes in substation primary equipment and secondary systems are being encouraged by the progress in digital communication and information technology. To survive in the competitive power market a new integrated system has been developed. It aims to introduce simple and compact primary equipment and intelligent secondary systems, as well as easy installation and intelligent substations. The newly developed integrated substation system applies nonconventional CT and VT, electronic signal interface between primary apparatus and upper level for control and equipment monitoring, process bus for realtime data communication, enhanced IEDs with web-server function, and substation control unit for local SCADA. In this paper the basic concept of the developed integrated substation system, features and configuration, technologies applied in each device, and practical examples of the service contents on the web-server are introduced.