Upstream-downstream optimization of volt-var control in smart grids

Author(s)

Laura Ribeiro Fardin

• Document type: Master's Dissertation
• Press: Campinas, SP.
• Institution: Universidade Estadual de Campinas (UNICAMP). Faculdade de Engenharia Elétrica e de Computação
• Defense date: 2023-03-09

Examining board members

Christiano Lyra Filho; Eduardo Nobuhiro Asada; Fábio Luiz Usberti

• Advisor: Fernanda Caseño Trindade Arioli; Christiano Lyra Filho

Abstract

Recently there has been a considerable increase in consumers with photovoltaic distributed generation. This new technology poses new challenges for the current distribution system since it is necessary to predict the bidirectional power flow at certain times of the day. Consequently, it may result in a voltage rise in some system buses. What in the long term can cause financial damage to consumers and the energy utility. Voltage and reactive power control (also known as Volt-Var control) aim to maintain acceptable voltage levels along distribution networks and minimize total active losses. Typically, control of traditional distribution network equipment is used, such as line voltage regulators, capacitor banks, and transformers with automatic tap switching under load (typically installed in the substation). However, with the advent of the intelligent inverter and its increasing use in photovoltaic solar generators, we can use this equipment to control voltage and reactive power. In addition, there is challenging to coordinate all this equipment in the current distribution networks so that the performance of one equipment is independent of the others. In this context, the present work proposes a centralized Volt-Var control strategy, which operates in pre-defined intervals of 15 minutes in the equipment available in the network (be they traditional equipment from the distribution network or intelligent inverters). This control aims to ensure that the distribution network operates at the optimal point, with minimal losses and a suitable voltage profile in all buses during the day. The proposed methodology was tested in four different networks with varying levels of photovoltaic penetration to prove the method’s effectiveness. The results showed a significant improvement in the voltage profile and reduced total losses compared to the case without any control. In addition, the results showed that a slight oversizing of the inverters (15%) generates even more minor losses (significantly when associated with large networks and with a high photovoltaic penetration) (AU)

• FAPESP's process: 21/04726-2 - Upstream-downstream optimization of volt-var control in smart grids
• Grantee: Laura Ribeiro Fardin
• Support Opportunities: Scholarships in Brazil - Master