Incremental Volt/Var Control for Distribution Networks via Chance-Constrained Optimization

TL;DR

This paper introduces a chance-constrained optimization-based incremental Volt/Var control scheme for distribution networks with high inverter integration, aiming to minimize reactive power while maintaining voltage safety with minimal communication.

Contribution

It proposes a novel chance-constrained optimization approach to tune Volt/Var controller parameters, ensuring voltage safety with probabilistic guarantees and local implementation without extra communication.

Findings

Successfully tested on a 42-node low-voltage network.

Effective in reducing reactive power usage.

Maintains voltage within safe limits with high probability.

Abstract

This paper considers an incremental Volt/Var control scheme for distribution systems with high integration of inverter-interfaced distributed generation (such as photovoltaic systems). The incremental Volt/Var controller is implemented with the objective of minimizing reactive power usage while maintaining voltages within safe limits sufficiently often. To this end, the parameters of the incremental Volt/Var controller are obtained by solving a chance-constrained optimization problem, where constraints are designed to ensure that voltage violations do not occur more often than a pre-specified probability. This approach leads to cost savings in a controlled, predictable way, while still avoiding significant over- or under-voltage issues. The proposed chance-constrained problem is solved using a successive convex approximation method. Once the gains are broadcast to the inverters, no additional communication is required since the controller is implemented locally at the inverters. The proposed method is successfully tested on a low-voltage single-phase 42-nodes network and on the three-phase unbalanced IEEE 123-node test system.