  In chance-constrained OPF models, joint chance constraints (JCCs) offer a
stronger guarantee on security compared to single chance constraints (SCCs).
Using Boole's inequality or its improved versions to decompose JCCs into SCCs
is popular, yet the conservativeness introduced is still significant. In this
letter, a non-parametric iterative framework is proposed to achieve the
decomposition of JCCs with negligible conservativeness. An adaptive risk
allocation strategy is also proposed and embedded in the framework. Results on
an IEEE test case show that the conservativeness using the framework is nearly
eliminated, thereby reducing the generation cost considerably.
