Real-Time Coordinated Voltage Control of PV Inverters and Energy Storage for Weak Networks With High PV Penetration

Abstract

Abstract-There are more large-scale PV plants being established in rural areas due to availability of low priced land. However, distribution grids in such areas traditionally have feeders with low X/R ratios, which makes the independent reactive power compensation method less effective on voltage regulation. Consequently, upstream Step Voltage Regulator (SVR) may suffer from excessive tap operations with PV induced fast voltage fluctuations. Although a battery energy storage system (BESS) can successfully smooth PV generation, frequent charge/discharge will substantially affect its cost effectiveness. In this paper, a real-time method is designed to coordinate PV inverters and BESS for voltage regulation. To keep up with fast fluctuations of PV power, this method will be executed in each 5s control cycle. In addition, charging/discharging power of BESS is adaptively retuned by an active adjustment method in order to avoid BESS premature energy exhaustion in a long run. Finally, through a voltage margin control scheme, the upstream SVR and downstream PV inverters and BESS are coordinated for voltage regulation without any communication. This research is validated via an RTDS-MatLab co-simulation platform, and it will provide valuable insights and applicable strategies to both utilities and PV owners for large-scale PV farm integration into rural networks.Index Terms--Coordinated voltage control, photovoltaic (PV), battery energy storage system (BESS), real-time control, state of charge (SOC) regulation.

Optimal scheduling of isolated microgrid with an electric vehicle battery swapping station in multi-stakeholder scenarios: A bi-level programming approach via real-time pricing

“…P are respectively the rated charge and discharge powers of the BSS. Capacity constraint: To limit the BSS capacity during each period to a reasonable range, it must obey the following constraint [26,40]:…”

Hierarchical Look-Ahead Conservation Voltage Reduction Framework Considering Distributed Energy Resources and Demand Reduction

“…In Case 2, the terms related to the PV systems and the ESSs in Equations (7) and (8) and all the SOC constraints presented in Equations (20), (21), (22), (23), (24), (25), and (26) are deleted. Furthermore, as only OLTC and CBs can regulate feeder voltages in Case 2, the terms related to the reserved power of the PV systems and the ESSs in Equations (27), (28), (29), and (30) are also eliminated. Our proposed algorithm is demonstrated in Case 3.…”

“…Recently, because the smart inverters of DERs can be used as fast-responding VAR supporting devices with the revised IEEE Standard 1547 for DER-grid interconnection and interoperability, a variety of multi-time scale-based distributed VVO schemes have been proposed, in which smart inverters and voltage regulating devices cooperate to smoothen the variations in voltage owing to rapidly fluctuating PV outputs and slowly changing load consumptions, respectively. These schemes include a multi-area voltage control scheme [20], a cooperative strategy between local control areas [21], a dynamic model of inverter-based DERs [22], a sensitivity analysis-based distributed control method [23], and a local power factor droop control curve [24], and the use of ESSs to improve the voltage profile [25][26][27][28]. More recently, considering uncertainties in the output of PV systems and the load demand, a robust three-stage look-ahead VVC framework was developed, in which OLTC/CBs (in the first stage) and PV inverters (in the second and third stages based on a local droop control curve) are controlled to regulate voltage [29].…”

Guest Editorial for the Special Section on Enabling Very High Penetration Renewable Energy Integration Into Future Power Systems

“…This work can further increase network flexibility and the capability of networks to accommodate increasing PV penetration. L. Wang et al proposed a real-time PV inverters and battery energy storage system (BESS) coordinated control framework for voltage regulation of a weak distribution network with large-scale PV integration [20]. The control strategy can help both utilities and PV owners for PV integration.…”