This paper focuses on optimal voltage regulator (VR) planning to maximize the photovoltaic (PV) energy integration in distribution grids. To describe the amount of dynamic PV energy that can be integrated into the power system

the concept of PV accommodation capability (PVAC) is introduced and modeled with optimization. Our proposed planning model is formulated as a Benders decomposition based bi-level stochastic optimization problem. In the upper-level problem

VR planning decisions and PVAC are determined via mixed integer linear programming (MILP) before considering uncertainty. Then in the lower-level problem

the feasibility of first-level results is checked by critical network constraints (e.g. voltage magnitude constraints and line capacity constraints) under uncertainties considered by time-varying loads and PV generations. In this paper

these uncertainties are represented in the form of operational scenarios

which are generated by the Gaussian copula theory and reduced by a well-studied backward-reduction algorithm

The modified IEEE 33-node distribution grid is utilized to verify the effectiveness of the proposed model. The results demonstrate that a PV energy integration can be significantly enhanced after optimal voltage regulator planning.