Alain Germond

Optimal Location of Multi-Type FACTS Devices in a Power System by Means of Genetic Algorithms

This paper presents a genetic algorithm to seek the optimal location of multi-type FACTS devices in a power system. The optimizations are performed on three parameters: the location of the devices, their types, and their values. The system loadability is applied as a measure of power system performance. Four different kinds of FACTS controllers are used and modeled for steady-state studies: TCSC, TCPST, TCVR, and SVC. Simulations are done on a 118-bus power system for several numbers of devices. Results show the difference of efficiency of the devices used in this context. They also show that the simultaneous use of several kinds of controllers is the most efficient solution to increase the loadability of the system. In all the cases (single-and multi-type FACTS devices), we observe a maximum number of devices beyond which this loadability cannot be improved.

Approaches for analog VLSI simulation of the transient stability of large power networks

This paper suggests several approaches for determining the transient stability of a power network by using an analog VLSI chip for simulating the system behavior. The main advantages of using this method are the much shorter computation time and lower complexity compared to the currently used methods, which are based on numerical calculations or discrete analog emulators.

Unsupervised neural net classification of power system static security states

The authors study the application of Kohonens self-organizing feature map to power system static security assessment. The Kohonen classifier maps vectors of an N-dimensional space to a two-dimensional neural net in a nonlinear way, preserving the topological order of the vectors which, in general, is not known a priori. The classification of line-loading patterns by the Kohonen network is demonstrated for two different test systems. The generalization capability of the Kohonen network permits the correct classification of system states which have not been encountered during the training phase. This feature is extremely important for power system operation where it is unrealistic to expect that all possible cases will be encountered during off-line simulation

Improving NERC Transmission Loading Relief Procedures

Abstract NERCs curtailment procedure can be significantly improved by curtailing more of those transactions with a bigger influence on the congested flowgates, and by curtailing multilateral packaged transactions as a package rather than on a bilateral basis.

Multi-agent Approach to Electrical Distribution Networks Control

A new approach to the configuration and operation of electrical distribution networks is proposed. Traditionally, the medium-voltage part of the electrical grid is operated in a centralised and static manner. In the context of electric sector deregulation and electric market liberalisation, the pertinence of this central organisation is no longer ensured. This paper presents an alternative approach based on a multi-agent system, implementing a distributed control algorithm. Concepts used in communication networks have been applied and adapted to the electrical supply system.

Decision Aid Function for Restoration of transmission power systems: conceptual design and real time considerations

This paper deals with the conceptual design of a decision aid function for restoration (DAFFOR) of transmission networks after major black-outs, and in particular with real time considerations. Some important characteristics of the proposed DAFFOR are: (a) capability of taking into account the dynamic evolution of the network state, due to either a control action or an unforeseen event; (b) interactive mode, which permits users to request a validation of their own suggestion; (c) coupling with an internal dynamic simulator which is solicited to validate any suggestion. At present, the DAFFOR is coupled with the French National Utility Operator Training Simulator (EDF OTS). After intensive testing within the OTS environment, the operational version of the DAFFOR will be developed.

Long-term energy management optimization according to different types of transactions

In this paper, the authors describe a method for energy management, according to minimal costs criteria over one year (month after month), of an electric utility, which has to deal with nuclear and hydroelectric power plants, sale/purchase and exchange contracts, and spot market business. The chosen method for minimizing the costs is linear programming with most variables being continuous, and a few binary ones. The results obtained allow the management of every power plant, contract and the spot market business, in order to respect the economic, physical and environmental constraints.

Analog VLSI solution to the stability study of power networks

This paper presents three basic approaches for determining the transient stability of a power network by using an analog VLSI chip for simulating or emulating the system behavior. The main advantages of using this method are the much shorter computation time and lower complexity compared to the currently used methods that are based on numerical calculations or discrete analog simulators.

Power System Stability Enhancement Using ANN Based Coordinated Emergency Control System

The paper presents an emergency control system based on the artificial neural network (ANN) technique. The control system is able to find a coordinated control action (load shedding, generator tripping) to prevent the violation of power system stability. Besides, the coordination of FACTS with conventional emergency control actions is studied. A 14 bus test power system is used as a case study. The efficiency of the proposed technique has been proved by numerical simulations under different power system operating conditions and for different emergency situations. The results obtained are presented.

Network Simplex Method Applied to AC Load-Flow Calculation

Operational research methods, and particularly flow and transportation methods have many applications in the power system field: optimization of hydroelectric power system operation, seasonal or short-time planning of a hydro-thermal system and finally power system security. The purpose of this paper is to specify the network simplex method of the load-flow calculation in a power system. This study is not limited to the DC-flow calculation but particularly presents a model for the full AC load-flow calculation. The proposed model is an imaginary and real current one. It is based on a simplifying assumption which will allow decoupling of the problem and which is the basis of the algorithm called FLF (Flow Load-Flow algorithm). Power system elements such as lines, transformers, generators and voltage control busses are represented with adapted models. Systematic tests have been performed on some existing power systems, such as the IEEE 24-bus Reliability system. The performance of this method is compared with the results of a decoupled Newton-Raphson load-flow. The accuracy of the FLF algorithm is competitive with the Newton-Raphson method, but its speed still has to be improved. However the load-flow calculation is only a part of the power system security problem, where properties and characteristics of flow and transportation algorithms will offer greater perspective.