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The paper makes an analysis of the eighteen 220 and 400 kV overhead electric lines belonging to C.N. Transelectrica - Sibiu Branch (TSO) on the basis of a unitary methodology for assessing their technical state and taking into consideration the different types of expertise conducted until now, including the multispectral analysis from the helicopter of seven lines. Performance criteria for insulators,...
Signal parameters estimation is an important prerequisite for assessment of power quality (PQ) indices. Nowadays, large amounts of measured data need to be automatically processed for appropriate and useful data mining in PQ. Especially, modern wind generators are often seen as sources of PQ disturbances, which should be constantly supervised. The authors propose an application of modified singular...
This work presents a new approach for placement and dispersing of decentralized generation (DG) power in medium voltage distribution networks based on continuation power flow (CPF) method. The main objectives of the proposed method are to maximize the normal operation loadability (NOL) (i.e. the maximum loading which can be supplied by the power system while the voltages at all nodes are kept within...
This paper presents a novel algorithm for the integration of wind generation with conventional power system for reliability studies. The algorithm is based on dividing the wind turbine generator (WTG) output power into corresponding four states. The mean time to fail (MTTF) and the mean time to repair (MTTR) are calculated for each state based on the generated power. A four-state model for WTG is...
This paper is treating the problem of quantifying the risk of a blackout in a power system when realizing off-line simulations for dedicated power system analysis. The issue consists in the computation of the stability limit for a power system, the concept of steady-state stability reserve being reviewed. Even in off-line simulation the stability reserve of a power system is not a straight forward...
This paper presents the results of parameter identification of static load characteristics on the basis of large number of field tests. The parameters of most frequently used, polynomial and exponential load model are determined using two different ways of normalization - normalization with voltage and power values just before the voltage change, and normalization with rated voltage and power values...
This document describes the determination of the saturated inductance of a transformer, which is the slope of the saturation curve Phi(I) under highly saturated conditions. This parameter, which has a strong impact on the overvoltages when energizing a transformer, has been determined from analytic formulae for a shell-type transformer. Comparisons with the values derived from an electromagnetic 3D...
Optimal voltage scheduling procedure is usually a part of a day-ahead or hour-ahead planning phase, done by Transmission System Operator (TSO). It provides an implementation of a voltage control ancillary service that consists of a planning phase based on optimal power flow algorithm, realtime operation and accounting and settlement. Voltage control ancillary service model described in the paper is...
This paper presents a new approach for an out-of-step protection system for transmission corridors in interconnected power systems. The novelty of this approach is its interdependence on having a complete observability of the system. A defense plan analyzes voltage phasors measured at different network locations to determine the security state of the transmission corridor. If a disturbed state is...
HVDC control has much faster inherent capability of the response than the dynamic response of the AC system. The valve firing angle control has a transient response time of only few milliseconds with the accuracy of a fraction of an electrical degree for firing the converter valves. Consequently, the control can have a significant influence on the improvements of system stability e.g. fast power recovery...
This paper defines and evaluates a model predictive control strategy with binary integer programming optimization for load shifting in a water pumping scheme. Both time-of-use and maximum demand charges are considered in the control model. The control model yields near optimal switching times which reduce time-of-use and maximum demand based electricity costs. Both the time-of-use and maximum demand...
This paper presents a new algorithm for protection of power transformer by using optimal radial basis function neural network (ORBFNN). ORBFNN based technique is applied by amalgamating the conventional differential protection scheme of power transformer and internal faults are precisely discriminated from inrush condition. The proposed method neither depend on any threshold nor the presence of harmonic...
This paper considers a procedure for multi-area static security assessment of large interconnected power systems operated by a team of transmission system operators (TSOs). In this procedure, each TSO provides the other TSOs with his own equivalent model as well as the detailed effects of contingencies in his control area on all tie-line flows. The paper deals with the implementation of sensitivity-based...
An industrial plant, such a power system, always contains parametric uncertainties. In the design of a controller the uncertainties must be considered. Otherwise, if the real plant differs from the assumed plant model, a controller designed based on classical controller design approaches may not ensure the stability of the overall system. In this paper a robust controller, based on the quantitative...
Electricity blackout can be treated as critical situation of any country in economical, political, and security point of view. Therefore, underfrequency load shedding is one of the most important protection systems, as in many cases it is the last measure for preventing system blackout after serious disturbances occur in the power system. First, the static analysis of Slovenian power system has been...
Power lines performance has traditionally been assessed in terms of their efficiency and reliability. The increase of the effect of voltage sags on sensitive loads may be located far away from the faulted line, claims for a new analysis of line performance. A new method to evaluate power lines performance is proposed and compared with the previous ones based on the power line reliability. The results...
Distributed Generation is increasing in nowadays power systems. Small scale systems such as photovoltaic, biomass or small cogeneration plants are connected to the distribution level, while large wind farms will be connected to the transmission level. Both trends lead to a replacement of large synchronous generators as the dominating generation technology. Up to now, transient stability of transmission...
This paper addresses the generation expansion-planning problem describing a model that generation companies and regulators can use to get insight to this problem and to more completely study and characterize different investment decisions. The simulation model considers a number of possible generation technologies and aims at characterizing the corresponding investment plans from an economic point...
This paper presents a novel model for the load forecast under uncertainty specially designed for markets under permanent evolution. The proposed approach does not rely on statistic models designed to reproduce the past. Instead, we make extensive use of intelligent models able to explain consumers' behavior and its specific characteristics. This model has gained importance in the present days, where...
In this paper, the stochastic characteristics of the electric consumption in France are analyzed. It is shown that the load time series exhibit lasting abrupt changes in the stochastic pattern, termed breaks, which need to be accounted for during the modeling process. Thus, a new robust diagnostic approach for which the identification of the breaks is carried out via a robust autocorrelation function...
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