Exploiting OLTC and BESS Operation Coordinated with Active Network Management in LV Networks

Abstract

The large number of small scale Distributed Energy Resources (DER) such as Electric Vehicles (EVs), rooftop photovoltaic installations and Battery Energy Storage Systems (BESS), installed along distribution networks, poses several challenges related to power quality, efficiency, and reliability. Concurrently, the connection of DER may provide substantial flexibility to the operation of distribution grids and market players such as aggregators. This paper proposes an optimization framework for the energy management and scheduling of operation for Low Voltage (LV) networks assuring both admissible voltage magnitudes and minimized line congestion and voltage unbalances. The proposed tool allows the utilization and coordination of On-Load Tap Changer (OLTC) distribution transformers, BESS, and flexibilities provided by DER. The methodology is framed with a multi-objective three phase unbalanced multi-period AC Optimal Power Flow (MACOPF) solved as a nonlinear optimization problem. The performance of the resulting control scheme is validated on a LV distribution network through multiple case scenarios with high microgeneration and EV integration. The usefulness of the proposed scheme is additionally demonstrated by deriving the most efficient placement and sizing BESS solution based on yearly synthetic load and generation data-set. A techno-economical analysis is also conducted to identify optimal coordination among assets and DER for several objectives.

Expert System Integrating Rule-Based Reasoning to Voltage Control in Photovoltaic-Systems-Rich Low Voltage Electric Distribution Networks: A Review and Results of a Case Study

“…Even under these conditions, the implementation of RBES in the real application integrated into the LVEDN depends on the speed and sampling step of the data transmission from the smart meters installed at the end-user level (in the study case, the sampling step was 60 min according to the setting implemented by the DNO at the level of the SMS) and the performance of the processing module from the data concentrator at the EDS level. Regarding the expected costs to implement the proposed voltage control solution, DNOs should consider an investment cost of 7000 euros and an approximated cost per tap position change of 0.01 euros, according to [54]. In addition, the costs allocated to the maintenance operations should be integrated into the economic analysis, but these are low due to the high reliability of the OLTC (700,000 tap position changes between two maintenance operations [41]).…”

Quantum binary particle swarm optimization for optimal on-load tap changing and power loss reduction

“…Real power, which represents the actual energy consumed or dissipated as heat, and reactive power, associated with the phase difference between voltage and current in AC circuits, are targeted for reduction. In (3) and (4), as referenced from sources [20], [21], play a pivotal role in guiding the minimization process. By focusing on these equations, the paper aims to provide a systematic approach to achieving optimal power management, thereby contributing to the economic efficiency and sustainability of the distribution system.…”

An Average Voltage Approach to Control Energy Storage Device and Tap Changing Transformers Under High Distributed Generation

“…In [22], a technique is proposed that allows a high-power generation by photovoltaic plants in a low voltage power distribution network by using a BESS to prevent overvoltage. In [23], a technique is presented that coordinate the OLTC, BESS and DGs for voltage regulation improvement. The strategy determines the optimal tap position of the OLTC at any point in time, the state of each BESS, and the reactive and active power outputs of each DG to ensure well-regulated voltage magnitudes and reduce line congestion.…”

“…When the electric vehicles SOC is not low enough to alleviate the voltage rise, the controller will curtail the active power generated by DGs. Although the techniques summarised in [14][15][16][17][18][19][20][21][22][23][24][25][26][27] are effective in regulating voltage magnitudes to a certain extent, their effectiveness can be enhanced by introducing an average voltage method of voltage regulation instead of a single point voltage regulation method. This is because the methods in literature control the OLTC and SVR with respect to a fixed reference voltage, or a reference voltage computed based on the highest/lowest measured/estimated voltage magnitude.…”