Electric power

About: Electric power is a research topic. Over the lifetime, 73036 publications have been published within this topic receiving 636991 citations.

Method and system for improved reliability in storage devices

Abstract: A method of preventing data loss in a data storage system includes supplying write data to a high speed volatile write buffer and supplying electrical power from an energy storage device upon detection of a primary power loss event. The backup electrical power is supplied to the write buffer and nonvolatile cache. Under backup power, the write data is transferred into the nonvolatile cache and the backup power is removed. Upon regaining main power, a data presence indication triggers a transfer of the write data from the nonvolatile cache to the long term storage media. The method may be implemented for a system to protect it from inadvertent power losses or it may implemented in a system where the long term storage device is power cycled to save power. The energy storage device is not necessarily needed in the power cycled system unless power failure protection is also desired.

Large-scale wind power integration and voltage stability limits in regional networks

Abstract: When planning and developing large-scale wind power plants in areas distant from the main power transmission system, voltage control assessments and reactive power compensation are increasingly important. Voltage stability of the regional network may be a main limitation with respect to maximum rating and operation of the wind power plant Technical constraints in relation to wind power integration in weak grids may in general be associated with limited thermal capacity in parts of the grid and/or the adverse effect wind power can have on voltage quality and stability. In certain situations, however, local constraints regarding development of new transmission lines or upgrading of existing lines can make it interesting to utilise the existing lines to a level which in worst case may imply operation beyond the normal technical constraints of the system. In this work, challenges and opportunities arising from situations as described above are analysed, and viable measures to enable secure and acceptable operation of large wind farms in remote areas close to the thermal capacity and stability limits of the power system, are pointed out. The paper presents results from computer analyses of a simplified, yet realistic, electrical power system with wind power integration, illustrating possible solutions to achieve this.

Ship to Grid: Medium-Voltage DC Concepts in Theory and Practice

Abstract: Corporate research centers, universities, power equipment vendors, end users, and other market participants around the world are beginning to explore and consider the use of dc in future transmission and distribution system applications. Recent developments and trends in electric power consumption indicate an increasing use of dc-based power and constant power loads. In addition, growth in renewable energy resources requires dc interfaces for optimal integration. A strong case is being made for intermeshed ac and dc networks, with new concepts emerging at the medium-voltage (MV) level for MV dc infrastructure developments.