This paper addresses the switching transients in multibranch thyristor-switched capacitors (TSCs). The current transients\r\nfollowing the addition of a branch to a group of already connected ones are analyzed. Expressions for both its fundamental and its\r\noscillatory components are given in terms of the power network voltage, frequency, short-circuit level, and the switching angle. The\r\nrelations include also the compensator parameters such as its total reactive power rating, total number of branches, the number\r\nof already connected branches, and the initial voltage on the capacitor involved in the switching transient. An expression for the\r\ndistortion of the supply current is also given. A minimization procedure is presented for identifying the optimal switching angle\r\nleading to the least magnitude of the oscillatory current. Switching when the instantaneous supply voltage is equal to the initial\r\nvoltage will result in the least oscillatory current only in the two special cases of a single-branch compensator, or in the switching\r\nof the first branch of a multi-branch TSC. The effect of both the total number of branches and the branch switching steps on the\r\noscillatory current and on the optimal switching angle is also discussed. The advantage of the suggested procedure is demonstrated\r\nby investigating several case studies.
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