Partial shading significantly impacts photovoltaic (PV) array performance, complicating design, efficiency optimization, and climate-specific simulations. Accurately predicting the current-voltage (I-V) characteristics under uneven irradiance requires solving coupled nonlinear equations-typically via computationally intensive numerical methods prone to divergence. To address this challenge, this work proposes an explicit analytical model for I-V curve calculation in Total Cross-Tie (TCT) configurations. This approach is computationally efficient and avoids numerical complexities. A parameterized model is derived using asymptotic methods, requiring only two measured points on the I-V curve. For the maximum power point (MPP), the proposed model necessitates solving an implicit equation; to address this issue, an analytical approximate solution is developed. The resulting closed-form expressions enable efficient simulation of I-V and P-V characteristics under partial shading and provide a fast analytical approximation of the global MPP in TCT arrays, making the proposed approach particularly suitable for system-level analysis, performance evaluation, and maximum power point tracking applications. The analytical formulas presented show an absolute percentage error (APE) ranging from 1.486% to 0.0014% for the power at the MPP, P mpp , in the TCT configuration.