Control Of Large-scale Networks Research Articles

Extensions and New Applications of the Traffic-Responsive Urban Control Strategy: Coordinated Signal Control for Urban Networks

The objectives, approach, advantages, and some application results of recent extensions of the traffic-responsive urban control (TUC) strategy are presented. Based on well-known methods of the automatic control theory, TUC allows for traffic-responsive coordinated signal control of large-scale urban networks that is particularly efficient under saturated traffic conditions. The first version of the TUC strategy controlled only the green splits. After initial development and the first field implementations and evaluations, TUC was expanded to perform real-time cycle and offset control, and to allow for public transport priority. Simulation investigations of the extended TUC application in parts of the urban networks of Tel Aviv and Jerusalem, Israel, by use of the AIMSUN microscopic simulator demonstrate the high efficiency of the new signal control strategy.

Efficient object oriented power systems software for the analysis of large-scale networks containing FACTS-controlled branches

This paper presents the methodology used in the development of a new generation of software suitable for the analysis and control of large-scale power networks containing FACTS-controlled branches. A Newton-Raphson load flow is used in this paper to emphasise the benefits and drawbacks introduced by the object-oriented technology when applied to 'number-crunching' power engineering solutions. The Newton-Raphson algorithm exhibits quadratic convergence for cases with FACTS-controlled branches. Full details of the prowess of this algorithm are given in a companion paper. C/sup ++/ has been used to develop compact and easy-to-maintain power systems conventional sparsity software. To aid portability the software has been developed under the UNIX/sup TM/ environment.

State Estimation Simulation for the Design of an Optimal On-Line Solution

A state estimation simulation package (SES) developed for studies and educational purposes was further upgraded with on-line capabilities and implemented as a production grade program into a large-scale network control system. Although conceived for different applications and run-time environments, this transformation was realized smoothly and relative quickly without modifying the algorithmic kernel; the result is an efficient state estimation package (SE) with real-time capabilities. The benefits of this development strategy are: - feasibility studies such as optimal metering are possible with a unified SE approach in the early phase of a new control center project; - the existence of a thoroughly tested SE simulation package accelerates the debugging phase of the on-line algorithm; - the joint effort speeds up the know-how transfer and feed-back between R&D and reduces the overall costs. A short description of the SES structure is given. The requirements and design goals of an on-line SE are outlined. Special emphasis is laid upon functional extensions such as: data base interfaces, the mapping of the network connectivity at equipment (terminal) level into a node/branch model and vice-versa, man-machine-interfaces, etc. Methods for software-quality enhancement, performance measurements and results obtained with the on-line SE on a VAX 11/780 are presented.