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The prevalence of missing values in the data streams collected in real environments makes them impossible to ignore in the privacy preservation of data streams. However, the development of most privacy preservation methods does not consider missing values. A few researches allow them to participate in data anonymization but introduce extra considerable information loss. To balance the utility and privacy preservation of incomplete data streams, we present a utility-enhanced approach for Incomplete Data strEam Anonymization (IDEA). In this approach, a slide-window-based processing framework is introduced to anonymize data streams continuously, in which each tuple can be output with clustering or anonymized clusters. We consider the dimensions of attribute and tuple as the similarity measurement, which enables the clustering between incomplete records and complete records and generates the cluster with minimal information loss. To avoid the missing value pollution, we propose a generalization method that is based on maybe match for generalizing incomplete data. The experiments conducted on real datasets show that the proposed approach can efficiently anonymize incomplete data streams while effectively preserving utility.

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The fault current limiter (FCL) is one of the most useful measures for limiting fault currents in power systems. This paper introduces a new structure for a parallel-type permanent magnet-biased saturation-based fault current limiter (PPFCL). The PPFCL consists of two magnetic devices connected in parallel and in magnetic counter opposite to each other. The operating principle and the core inductances in different states were analyzed using an electromagnetic equivalent circuit. In addition, a 220V/10A experimental prototype was designed and tested in a simple system and compared with Maxwell-3D simulation and analytical methods. Finally, a 10-kV case-study model was created and compared with a series-type FCL, which verified the effectiveness of the limiter in high-voltage, large-capacity application. Experimental and simulation results have demonstrated that the PPFCL exhibits fast response and low impedance during normal operations, as well as high bias capability and low possibility of demagnetization of the permanent magnet during fault conditions.Index Terms-Fault current limiter (FCL), permanent magnet, topology, parameter design.

Wind power prediction is important for the smart grid safe operation and scheduling, and it can improve the economic and technical penetration of wind energy. The intermittent and the randomness of wind would affect the accuracy of prediction. According to the sequence correlation between wind speed and wind power data, we propose a method for short-term wind power prediction. The proposed method adopts the wind speed in every sliding data window to obtain the continuous prediction of wind power. Then, the nonlinear partial least square is adopted to map the wind speed under the time series to wind power. The model carries the neural network as the nonlinear function to describe the inner relation, and the outputs of hidden layer nodes are the extension term of the original independent input matrix to partial least squares regression. To verify the effectiveness of the proposed algorithm, the real data of wind power with different working conditions are adopted in experiments. The proposed method, backpropagation neural network, radial basis function neural network, support vector machine, and partial least square are performed on the real data and their effectiveness is compared. The experimental results show that the proposed algorithm has higher precision, and the real power running curves also verify that the proposed method can predict the wind power in short-term effectively.

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To reduce the requirement of DC-coil-generated magneto-motive force (DC MMF), this paper analyses the method of using permanent magnets (PMs) to saturate the core. In this paper, a novel bridge-type hybrid saturated-core fault current limiter (BHFCL) is proposed to investigate the influence of PM. For the BHFCL, a bridge structure is designed to guarantee fault clipping performance, with a fault limiting reactor. Also, the compact structure of magnetic device and the shared coil of AC and DC could reduce cost and losses. To compare the influence of PMs on the performance of BHFCL and validate the effectiveness of the proposed BHFCL, various FEA simulation models in a simple system are carried out by ANSOFT. Simulation results demonstrate that the BHFCL could achieve considerable energy consumption reduction with little effect on the normal condition voltage drop as well as fault clipping ability. The BHFCL is efficient in fault clipping and the performance is shown to depend mainly on the value of the reactor included in the bridge.Index Terms-Fault current limiter (FCL), permanent magnet, steel core, magneto-motive force (MMF).

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