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This article presents a unit protection scheme for bipolar dc microgrids, which is resilient to cyber attacks. The proposed method uses current measurement of both ends of the protected line segment for distinguishing the internal faults and cyber attacks. For any change in current, the disturbance index exceeds the threshold value, subsequently, the proposed protection algorithm is triggered. Being a bipolar dc system, the concept of symmetrical component decomposition is used to obtain the bias, unbalance, and balance components during an unbalance condition. The superimposed balance component of both ends of the line on a four-quadrant plane acts as a decisive discriminator between internal and external faults. The correct faulted pole is identified by analyzing the superimposed unbalanced component. By comparing the superimposed bias component with the local pole domain currents, the cyber attack is correctly identified. The proposed protection scheme is validated on a ring-type bipolar dc microgrid, simulated in real-time digital simulator, for different internal and external faults and cyber attacks. The performance of the proposed method is tested for various conditions, including the detection of internal and external high resistance faults, fault type classification, change in load, distinguishing between different faults, and cyber attacks. A comparative assessment of the proposed method with the available techniques confirms its strength.

There have been several contentions, characterisations and controversies over Max Weber’s treatment of history in his sociological writings both during his lifetime and after him as well. While some contest his contentions, others doubt the type of English translations made of his German writings. There is a need to take stock of and consolidate the sociologically relevant historical writings of Max Weber in proper perspective. The article raises the following two issues: (a) How can the claim be justified that Max Weber is one of the users of the comparative historical approach rather than one belonging to those using the evolutionary historical approach? (b) What are the specialities of his treatment of history in his methodology and substantive works? It is the specific intention of this article to consolidate the historical materials in the sociological writings of Weber so as to reconstruct his comparative historical approach as against positivist evolutionary history.