Accurate Solutions for Two-Cascaded Sections

Considering the characteristic of hyperbolic functions, for example, B1C2 = C1B2 and A1B2 + B1A2 = Zq sinh 0, the earlier equations are rewritten in the form of the hyperbolic functions. For example, 

R = (R1R2 + R2R3 + R3R1) cosh 01 cosh 02 + RiZo cosh 0i sinh 02 

The earlier solutions become identical to those in Equation 6.16 when the approximation in Equation 6.7 is adopted. 

Working Group (Chair Agematsu, S.) Japanese Electrotechnical Research Association. 2002. Technologies of countermeasure against surges on protection relays and control systems. ETRA Report 57 (3) (in Japanese). 

Matsumoto, T., Y. Kurosawa, M. Usui, K. Yamashita, and T. Tanaka. 2006. Experience of numerical protective relays operating in an environment with high-frequency switching surges in Japan. IEEE Trans. Power Deliv. 21(l) 88-93. 

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