Interconnected Electric System Research Articles

Optimal Energy Transactions in Interconnected Electric Systems

A method is developed to calculate optimal exchanges of energy within a large system of interconnected electric utilities. The model uses linear programming to dispatch both generation and sales between the utilities, in a way which minimizes energy costs for the entire system, within transmission constraints. A Monte Carlo process is used to select random levels of available generation and load in the system, and each resulting state is optimized. The results of many optimizations are averaged to arrive at the results.

Hierarchical Dynamic State Estimation in Electric Power Systems

Abstract In many countries, huge power networks are formed-from the interconnection of electric power companies, each one having its own supervisory control center. In order to supervise efficiently such power systems, hierarchical state estimation techniques have to be considered. This paper presents a new algorithm using hierarchical concepts to solve the dynamic state estimation (DSE) problem for large-scale electric power system operating under quasi-static conditions. A two-level calculation is performed to give a satisfactory solution from the computational point of view for the usual steps of the DSE procedure: model parameter estimation, state prediction and state filtering. At the local level, a conventional DSE algorithm is carried out simultaneously and independently for (all subsystems. The coordination of these local estimations is obtained at a national center for supervision and control, which is at the top of operational hierarchy in the interconnected electrical system. Numerical results show the performance of the proposed algorithm under different operational conditions: normal, sudden variation of states and occurrence of bad data.

Load Following Impacts of a Large Wind Farm on an Interconnected Electric Utility System

Load Following Impacts of a Large Wind Farm on an Interconnected Electric Utility System

Real-Time Computer System for the National Energy Control Center of MEXICO

The Mexican Interconnected Electrical System of Comisión Federal de Electricidad (CFE) has an installed capacity of 17600 MW and a main transmission grid of 400 and 230 KV spreaded around the country, covering an approximated area of 2000 000 sq. km. The annual rate of grow is about 10%.System Control is organized in six area control centers under the coordination of the National Control Center (CENACE). This paper makes a brief description of the Multi-level configuration of the computer system for the National Control Center of Comisión Federal de Electricidad, expected to be in service by 1983.Software structure is described with special interest in advanced network analysis programs, such as: Network Configuration (NC), State Estimator (SE), Real-Time Equivalents (RTEQ), Real-Time Security Analysis (RTSA) and On-line Load Flow (OLF).Multi-Area Generation algorithm based in a constrained economic dispatch and a real time area interchange calculation is also briefly described.

Automation developments in the control of interconnected electric utility systems

The rapidly increasing capability of the digital process control computer permits the economic solution of many electric utility system operating problems in a more accurate and timely manner. In this paper, the extension of the application area from the field of economic dispatch of generation to more sophisticated functions of system security is traced. Other related problems in the area of operations planning, operations control, and operations accounting are also reviewed. The requirements of communication systems to provide remote input data to the process computer are discussed, and the close interrelation of business and process computers is recognized. Information display is shown to play a very significant part in providing output to the system operators for further action. Concurrent with the developments in hardware have been significant advances in analytical techniques to encompass the increasing number of problems of system operation. These are reviewed in relation to the two major concerns, system security and system economics. An integrated information and control system may he achieved today for business, engineering, and system operation as a result of significant developments in hardware and in problem solution concepts. The optimum application of these improved equipments and analytical tools requires a total systems viewpoint in relation to both hardware and software.

Electric system expansion in the Pacific Southwest

THE PACIFIC SOUTHWEST area includes all of the interconnected electric systems in Arizona, California, and southern Nevada. The area, 380,000 square miles, is 12.5 per cent of the land area, contains 7.7 per cent of the estimated population, and uses 10 per cent of the energy generated by central stations in the United States. The area is generally arid and because of uninhabited mountain and desert areas, the electrical service areas of the three states cover less than one-fifth of the land area.

Selection, Design, and Operation of Power Transformers on American Gas and Electric Company System

This paper discusses briefly the philosophy underlying power transformer practices on the American Gas and Electric Company system. It includes power transformers used in generating, transmission, and distribution stations. It does not include transformers generally used on distribution lines to serve residential customers, or special purpose transformers not directly associated with the transmission and distribution of power. The size and extent of the interconnected electric system on which the transformers are used are described, and the requirements of such a system discussed. Considerations entering into the selection of transformers, their general design requirements, operation, and maintenance, including principles of loading, flexibility of use, and spare transformer practices, are amplified in considerable detail. Over-all economics are emphasized. The power transformer is a most important piece of apparatus in modern electric power systems, being second only to the generator. It makes possible the widespread use of power. In larger sizes it is the largest, heaviest, and most costly piece of electric equipment, except for the generator. In total rated capacity it far outranks all other elements; hence it is worthy of the utmost attention in our search for construction and operating economies. Fortunately, the present-day power transformer is a most dependable piece of electric equipment. It has become so reliable that interruptions to service because of transformer failure are rare. Notwithstanding, however, there is great need for less costly transformers that are still more reliable and require less maintenance. These are the goals we seek.

Increased power supply for Northern Illinois

In northern Illinois, four interconnected electrical utility systems have embarked on a postwar construction program to augment their collective generating capacity. When the project is completed they will be able to supply 3,000,000 kw of power. Equipment additions will cost $428,000,000, one-half of this estimated expense going for distribution facilities.