A 50 kV surge arrester will be installed on an effectively grounded 15 MVA, 33/11 kV transformer at a 33 kV three-phase system. The basic insulation level of the transformer is 3X0 kV. The arrester ratings and its protective voltage level are shown in Table 1. For 33 kV nominal voltage, the system's maximum voltage is 36 kV. Verify whether this surge arrester is suitable for the protection of the transformer or not (where X is 8). Jadual 1/ Table 1 Penangkap kilat/ Arrester #1 #2 # 3 # 4 Kadar penangkap kilat/ Arrester rating (kVrms) 75 60 50 36 Voltan limpahan denyut maksimum / Maximum impulse flashover voltage (kV peak) 270 216 180 130 Voltan lebihan hadapan gelombang maksimum / Maximum wavefront flashover voltage (kV peak) 310 250 207 150

A 50 kV surge arrester will be installed on an effectively grounded 15 MVA, 33/11 kV transformer at a 33 kV three-phase system. The basic insulation level of the transformer is 3X0 kV. The arrester ratings and its protective voltage level are shown in Table 1. For 33 kV nominal voltage, the system's maximum voltage is 36 kV. Verify whether this surge arrester is suitable for the protection of the transformer or not (where X is 8). Jadual 1/ Table 1 Penangkap kilat/ Arrester #1 #2 # 3 # 4 Kadar penangkap kilat/ Arrester rating (kVrms) 75 60 50 36 Voltan limpahan denyut maksimum / Maximum impulse flashover voltage (kV peak) 270 216 180 130 Voltan lebihan hadapan gelombang maksimum / Maximum wavefront flashover voltage (kV peak) 310 250 207 150

Introductory Circuit Analysis (13th Edition)

13th Edition

ISBN:9780133923605

Author:Robert L. Boylestad

Publisher:Robert L. Boylestad

Chapter1: Introduction

Section: Chapter Questions

Problem 1P: Visit your local library (at school or home) and describe the extent to which it provides literature...

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(a) A 5 MVA 230/11.5-kV single-phase power transformer has a per-unit resistance of 1.5% and a per-unit reactance of 6% (data taken from the transformer's nameplate). The transformer approximate equivalent circuit is given in the figure below. The open-circuit test performed on the low-voltage side of the transformer yielded the following data: Voc = 120 kV loc = 12 A Poc = 40 kW Refer to the low-voltage side of the transformer and calculate: (i) The value of Req and Xeq. (ii) The value of Rc and Xm. (ii) The voltage regulation when secondary voltage Vs = 11 kV and the secondary current Is = 350 A. kIp Reg jXcq 1, Vp Re V.
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A 3-phase, 50 Hz, oil cooled core type transformer has the following dimensions: distance between core centres 0.4 m, height of window 0.48 m, dia of circumscribing circle 0.28 m. The flux density in the core is 3.00 Wb/m² and the current density in the conductors is 5.0 N/mm². Estimate the KVA rating. Assume a window space factor of 0.4 and a core area factor= 0.56 the core is 2 stepped.