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.
Impact of wind power generation on distribution systems
A significant amount of wind power is being installed at the distribution level through the installation of wind power generation facilities in many parts of the United States and Canada. These generators operate in parallel with utility distribution feeders. It is forecasted by many experts that the installation of wind power generation will be increased due to the need to provide more clean energy. Utility regulators are encouraging wind power by setting high buy-back rates or setting goals for utilities to provide a portion of their generation from green sources. This paper discusses wind power generating sources (of 3 MW or less), which are connected to the utility system at the distribution level, and their impact on the distribution system. The paper will also discuss the various types of wind generators (Type I through IV) and their fault current contributions to system supply faults.
Local- and Wide-Area Network Protection Systems Improve Power System Reliability
Increasing demands on electricity supply, with the need for system economic optimization and power system growth limitations, have a significant impact on power system reliability. When the system operates in extreme conditions, load shedding, generation shedding, or system islanding must occur to prevent total system collapse. Typical causes of system collapse are voltage instability or transient angle instability. New monitoring, protection, and communications technologies allow us to implement economical local- and wide-area protection systems that minimize risk of wide-area system disruptions or total system collapse. This paper presents solutions that use programmable logic capabilities, faster communications, and synchronized phasor measurements available in meters and protective relays to prevent system disruptions