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The penetration level of wind energy is continuously growing, and it is especially relevant in European countries such as Denmark, Germany, and Spain. For this reason, grid codes in different countries have been recently revised, or are now under revision in order to integrate this energy in the network taking into account the security of supply. This paper is related to reactive compensation, which is one aspect usually included in these codes. On the other hand, a great number of installed wind parks are formed by fixed speed wind turbines equipped with induction generators. The typical scheme for reactive compensation in this kind of wind parks is based on capacitor banks locally controlled in each machine. This configuration makes very difficult to follow the requirements of the new grid codes. To overcome this problem, a configuration with a central controller that coordinates the actuation over all the capacitor steps in the wind park is proposed in this paper. A central controller algorithm that is based on a dynamic programming is presented and evaluated by means of simulation. At this time, the proposed scheme has been installed at the Sotavento Experimental Wind Park (Spain) and it is currently being tested. [ABSTRACT FROM AUTHOR]

This paper presents an effective algorithm to protect unfused 22.9-kV shunt capacitor banks in grounded-wye connection by improving an existing voltage difference method-based algorithm. It has often been reported that it is difficult to detect ground faults with arc near the input points within the bank using existing algorithms that use only the magnitude of the differential voltage. In this paper, it is shown that ground faults with arc near the input point can be detected by fast Fourier transform (FFT) analysis of the differential voltage and that the proposed algorithm is not impacted by harmonics generated by nonlinear loads which have quantitative influence on the capacitor banks. Consequently, the proposed method using harmonics analysis can be applied as an extended version of the existing detection method. The proposed method is applied to a simplified 22.9-kV real-life Korea Electric Power Corporation system and it is verified that the proposed algorithm can clearly detect faults that are not easily detected by the existing method. [ABSTRACT FROM AUTHOR]

This paper presents a new genetic algorithm (GA)-based approach for the simultaneous power quality improvement and optimal placement and sizing of fixed capacitor banks in radial distribution networks in the presence of voltage and current harmonics. The objective function includes the cost of power losses, energy losses and that of the capacitor banks. Constraints include voltage limits, number/size and locations of installed capacitors (at each bus and the entire feeder) and the power quality limits of standard WEE-S 19. Candidate buses for capacitor placement are selected based on an initial generation of chromosomes. Using a proposed fitness function, a suitable combination of objective and constraints is defined as a criterion to select (among the candidates) the most suitable buses for capacitor placement. A genetic algorithm computes improved generations of chromosomes and candidate buses until the solution is obtained. Simulation results for two IEEE distorted networks are presented and solutions of the genetic algorithm are compared with those of the maximum-sensitivities-selection (MSS), the maximum sensitivities selection-local variations (MSS-LV), and the fuzzy set algorithms. The main contribution of this paper is the computation of the near global solution, with weak dependency on initial conditions. [ABSTRACT FROM AUTHOR]