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The sample division-based hybrid model is an enforceable approach to improve wind power forecasting accuracy in the short term. These models up to now prefer to keep the input same for all the individual schemes, which weaken the effort of division and restrict the further improvement of the accuracy. To this end, a weather division-based wind power forecasting model with ensemble feature selection is proposed for refinement. The methodology comprises three stages: the division of wind power associated weather based on hierarchical clustering with the DTW distance metric, ensemble feature selection framework considering both predictive accuracy and stability, and wind power prediction based on machine learning algorithms for each weather type. As a test case, the proposed methodology is applied to the data of a wind farm group in Northwest China. With respect to the single models, the proposed method has improved the predictive accuracy by up to 30% at three error metrics, and the weather associated features are discussed.

Armature is very important for a synchronous induction coil launcher which can transform the electric energy to kinetic energy and push the load forward. The structure of the armature will influence the kinetic energy conversion efficiency directly. This paper analyzes the armature structure of a capacitor-driven synchronous induction coil launcher. Length and thickness of the armature are analyzed that how these parameters influence the maximum velocity and system efficiency of the launcher. Current filaments model is used to calculate the motion characteristics of a tubular linear induction motors, which is verified by an experiment and finite-element code. Genetic algorithm optimizer is used to calculate the best trigger times of the coils and the maximum velocity under the conditions of different length and thickness of the armature. It is shown that when the armature mass is fixed, length and thickness of the armature will greatly increase the velocity of the armature. The best length of the armature should be almost 2–2.5 times the length of the coil. The best thickness of the armature could be estimated by skin depth.

The presence of distributed generators (DGs) with high penetration poses new challenges in the management and operation of electrical grids. Due to the local character of DGs, they could in principle be used in emergency situations to prevent a voltage instability event of the grid. In this paper, a certain method is proposed to coordinate the operation of virtual power plant (VPP) and conventional voltage regulation device to improve the static voltage stability of distribution network with the multi-agent framework. The concept and the general framework of this coordinated control system is introduced, and the voltage instable nodes are determined based on the voltage instability indicator. The voltage coordinated control model of the distribution system is established according to the multi-agent consistency control theory and the coordinated controllers for agents are designed by solving a problem with bilinear matrix inequality constraints. The suggested method is implemented on an IEEE 33 nodes test system and the simulation results show its efficiency and validity.

Based on existing domestic and international standards and norms, this paper conducts a preliminary study on the technical requirements as proposed from the perspective of grid on microgrids during their grid-connecting, grid-connection operation and islanding processes. The basic principles and grid-connecting norm of microgrid grid-connection is proposed, and the requirements of the access point, capacity of access and access schemes are presented based on the considerations of reliability of distribution network. The issues caused by microgrids grid-connection, such as power quality, power control, voltage regulation, relay protection, communication, monitoring, energy metering and so on are analyzed in detail. The mode of the Microgrid disconnection has been divided into intention and unintention islanding types, and the principle of region islanding and disconnection requirements of the accident islanding mode are stressed. The analysis result of the key issues of grid-connected microgrid can be used as an useful foundation for the development of standards of microgrid grid-connected in the future.

A new topology of hybrid power filter is proposed in this paper, which consists of a C-type filter and an active filter. The application of C-type filter not only reduces the rating of active filter but also prevents the resonance occurring significantly when proper parameters are used. The Iterative Learning Control (ILC) method is applied to the realization of harmonic compensation. In this paper, both the topology and the control method are discussed. Experimental results based on the proposed topology and control method are presented.

Support vector machine (SVM) based on the principle of structure risk minimization provides a new perspective in machine learning, and has been successfully applied to many areas in the last years, especially for pattern recognition and function fitting. In this paper, because of the adjustable resolution of the SVM algorithm, a new way to measure interharmonic is put forward, namely using wide analytical domain of frequency with low resolution at first and then using narrow analytical domain of frequency with high resolution to obtain the frequency spectrum of the signal. And based on this new method, the interharmonic detection system is designed and implemented with the prevailing and powerful software platform of LabVIEW with graphical nature.

Based on digital signal processor (DSP) and intelligent module (IPM), this paper provides an example of vector control frequency conversion driving system, in which the fuzzy control algorithm is employed to improve control performance. The speed loop and current loop are employed in the frequency conversion system, where speed loop adopts automatic tuning control of fuzzy parameter, and the current loop adopts PI control.

With adaptive orthogonal decomposition of reactive and active current, an active AC bridge, which is implemented by employing analog circuit, is introduced. Its application in measurement of dielectric loss angle for high voltage insulation apparatus can eliminate the effect of harmonics of testing voltage, reduce leakage resistance and capacitance and ease high resolution. Moreover, determination of the reference voltages for orthogonal decomposition and the dynamical characteristics of the bridge are presented.

This paper introduced the concept and modeling of agents and three manners of multi-agent systems (MAS). On the basis of MAS, this paper presents a modeling method for management information systems (MIS) to overcome the shortage of information transfer manner in electric power enterprises. The framework of MIS based on MAS is developed, and two examples are discussed to illustrate the interior framework of agents in MIS of electric power enterprises.