Pseudo-gradient Based Local Voltage Control in Distribution Networks

Voltage regulation is critical for power grids. However, it has become a much more challenging problem as distributed energy resources (DERs) such as photovoltaic and wind generators are increasingly deployed, causing rapid voltage fluctuations beyond what can be handled by the traditional voltage regulation methods. In this paper, motivated by two previously proposed inverter-based local volt/var control algorithms, we propose a pseudo-gradient based voltage control algorithm for the distribution network that does not constrain the allowable control functions and has low implementation complexity. We characterize the convergence of the proposed voltage control scheme, and compare it against the two previous algorithms in terms of the convergence condition as well as the convergence rate

Class of Quadratic Almost Bent Functions That Is EA-Inequivalent to Permutations

The permutation relationship for the almost bent (AB) functions in the finite field is a significant issue. Li and Wang proved that a class of AB functions with algebraic degree 3 is extended affine- (EA-) inequivalent to any permutation. This study proves that another class of AB functions, which was developed in 2009, is EA-inequivalent to any permutation. This particular AB function is the first known quadratic class EA-inequivalent to permutation

Distributed Real-Time Voltage Regulation in Distribution Networks

The increasing penetration of renewable and distributed energy resources (DERs) in distribution networks call for fast and efficient distributed voltage regulation algorithms. This thesis first studies the existing local Volt/VAR control and designs new local algorithms with less restrictive convergence conditions and better voltage regulation. Meanwhile, unlike the traditional assets owned and managed by utility companies, the customer-owned DERs are not necessarily subject to the control of network operators unless properly incentivized. This thesis then investigates the joint design of distributed control and incentive mechanisms for managing DERs by introducing a market-based voltage regulation framework and extending it to a real-time setting with both continuous and discrete decision variables as well as device dynamics under time-varying operating conditions. The resulting randomized distributed algorithm admits asynchronous implementation in practical systems, and its performance is analytically characterized as well as numerically evaluated