Phasor-Based Control for Scalable Solar PV Integration

IEEE Access

Reliable and resilient grid operations with high penetration levels of distributed energy resources (DERs) can be achieved with improved situational awareness and seamless integration of DERs with utility enterprise controls. This paper presents the details of the development of a data-enhanced hierarchical control (DEHC) architecture and the results of its evaluation. The DEHC is a hybrid control framework that enables the efficient, reliable, and secure operation of distribution grids with extremely high penetrations of solar photovoltaic (PV) generation by seamlessly integrating centralized utility controls, distributed controls for DERs, and autonomous grid-edge controls. In the DEHC architecture, the advanced distribution management system (ADMS) controls the legacy devices (such as load tap changers and capacitor banks), the PV smart inverters are dispatched by real-time optimal power flow, and the gridedge devices regulate local voltages in coordination with each other. The DEHC is demonstrated using a commercial ADMS platform, real utility distribution feeder models, and grid-edge devices. The performance of the DEHC architecture is evaluated using simulations and hardware-in-the-loop experiments with voltage regulation as the control objective. The results show that the DEHC enables high penetration levels of PV in distribution feeders by effectively managing system voltages through the synergistic operation of ADMS, distributed PV smart inverter controls, and secondary-level grid-edge device control. INDEX TERMS Advanced distribution management system, distributed energy resource management system, distributed PV, distribution system, grid-edge control, optimal power flow, voltage regulation.

Sustainability, 2021

The increasing demand of electrical energy and environmental concerns are invigorating the use of renewable energy resources for power generation. Renewable energy resources can provide an attractive solution for present and future energy requirements. In this scenario, solar photovoltaic systems are becoming prominent and sustainable solutions with numerous advantages. However, the utilization of solar photovoltaic systems in distribution generation makes it mandatory to deploy efficient and organized control measures for integrating solar photovoltaic plants with the grid. In this paper, the control of grid-tied solar photovoltaic systems using a Kalman filter-based generalized neural network is presented with a variable step size perturb and observe-based maximum power point tracking controller to extract the maximum power from a solar photovoltaic plant. The presented system provides power-quality enhancement and supports a three-phase AC grid. The proposed approach extracts the...

IET Conference Publications, 2009

The connection of photovoltaic installations (PV) on a distribution network can cause important variations of voltage. Without regulation to maintain the voltage of the PV within the acceptable limits, that can cause a tripping of the PV. Thus this paper presents a development of a local voltage control based on auto-adaptive voltage control of PVs. This device by using local information permits to facilitate the connection of PVs and to reduce the cost of connection. This solution is able to control voltage not only at the connection point but also everywhere on the grid. The proposed solution is tested for a LV distribution network with presence of different types of PV with satisfied results.

IEEE Journal of Emerging and Selected Topics in Power Electronics, 2017

Proliferation of rooftop solar PV distributed generator (PVDG) installation in low voltage distribution network (LVDN) imposes voltage fluctuation challenges that are a threat to distribution system operators. Reactive power control (RPC) methods are insufficient in isolation to combat the overvoltage fluctuations manifested in LVDN with significant grid-tied PVDG installations. Whereas active power curtailment (APC) control can alleviate the voltage fluctuation in such situations and it is achieved at the cost of reduced active power injection. This paper explores how deficiencies in both RPC and APC as separate approaches can be mitigated by suitably combining RPC and APC algorithms. Strategies combining two RPCs and one RPC in conjunction with APC are proposed as two coordinating algorithms by means of instantaneous measurement of node voltage and active power. These coordinating algorithms are embedded in all the rooftop PVDG grid-tied-inverters (GTI), where the GTI coordinates among them for voltage support without exceeding individual inverter VA rating. The result of the combined approach show significant improvement in managing and stabilising the voltage and allows the penetration of PVDG to be increased from 35.65% to 66.7% of distribution transformer (DT) kVA rating.

2014 11th International Conference on Electrical Engineering/Electronics, Computer, Telecommunications and Information Technology (ECTI-CON), 2014

Rapid changes in the output of photovoltaic (PV) generations may lead to serious voltage fluctuation in distribution systems. This paper proposes a controlling method of only PV plants those have had active power changes to suppress the fluctuation. Without a requirement of high speed data exchange between the PV plant and the utility control center for voltage regulation, the proposed method helps a PV plant inject/absorb a proper amount of reactive power to/from the utility grid. Effectiveness of the proposed method is illustrated by a simulation in Matlab/Simulink.

2021

This paper presents a hierarchical control system to provide ancillary services from a solar PV power plant to the grid without the need for additional non-solar resources. With coordinated management of each inverter in the system, the control system commands the power plant to proactively curtail a fraction of its instantaneous maximum power potential, which gives the plant enough headroom to ramp up or down power production from the overall power plant, for a service such as regulation reserve, even under changing cloud cover conditions. A case study from a site in Hawaii with one-second resolution solar irradiance data is used to verify the efficacy of the proposed control system. The algorithm is subsequently compared with an alternative control technology from the literature, the grouping control algorithm; the results show that the proposed hierarchical control system is over 10 times more effective in reducing generator mileage to support power fluctuations from solar PV pow...

Proceedings of the 52nd Hawaii International Conference on System Sciences, 2019

The emergence of distributed generation in the low voltage distribution networks has led to new challenges in the regulation of feeder voltages. Of particular significance is the variability associated with the photovoltaic power and its impact on the operation of some of the mechanically switching voltage regulating equipment such as On-load Tap Changers (OLTCs) and switchable capacitor banks. This article attempts to study the effects of increased penetration of distributed generation, in particular photovoltaic power and a sustained load buildup on the operational activity of voltage regulators placed on a radial distribution feeder. Actual feeder load profile and high frequency solar irradiance data has been used with varying levels of PV penetration during the time period which spans an entire year. With the inclusion of some justifiable assumptions, it is concluded that the increased penetration of photo voltaic power adversely affects the operational lifetime of voltage regulating equipment.

Providing reliable electrical power to consumers at minimal cost presents a significant hurdle, particularly given the rising energy expenses owing to limited transmission capacity and the additional strain on power plants required to ensure a consistent supply. Renewable energy sources, particularly solar power are crucial for the future evolution of power systems owing to their cost-effectiveness and eco-friendliness. These alternatives offer new ways to complement existing grid infrastructure. Over the past ten years, various factors have reduced barriers to entry for photovoltaic systems, including improved solar cell efficiency, decreased costs, increased government incentives, and other considerations. Consequently, photovoltaic (PV) systems have become increasingly prominent in the global energy landscape. This project aims to develop a model for an intelligent power system that integrates multiple gridsynchronized energy sources. This system reduces consumer unit costs, ensures a steady electricity supply, enhances the current grid by feeding back excess power, and employs a smart algorithm to select the optimal power source from among the various options. Furthermore, it provides a locally generated, relatively affordable, and efficient solution for both businesses and consumers.

The main objective of this study is to increase the penetration level of photovoltaic (PV) power production in low-voltage (LV) grids by means of solar inverters with reactive power control capability. This paper underlines weak points of standard reactive power strategies which are already imposed by certain grid codes, and then, the study introduces a new reactive power control method that is based on sensitivity analysis. The sensitivity analysis shows that the same amount of reactive power becomes more effective for grid voltage support if the solar inverter is located at the end of a feeder. Based on this fundamental knowledge, a location-dependent power factor set value can be assigned to each inverter, and the grid voltage support can be achieved with less total reactive power consumption. In order to prevent unnecessary reactive power absorption from the grid during admissible voltage range or to increase reactive power contribution from the inverters that are closest to the transformer during grid overvoltage condition, the proposed method combines two droop functions that are inherited from the standard cosϕ(P) and Q(U) strategies. Its performance comparison in terms of grid losses and voltage variation with different reactive power strategies is provided by modeling and simulating a real suburban LV network.

IEEE Access, 2021

In recent years, with increasing the penetration of renewable-based distributed generations, voltage control plays a vital role in operating distribution systems. Furthermore, the traditional voltage control devices are not fast enough to regulate the voltage due to transient events and the intermittent characteristics of renewable energy sources. On the other hand, because of the fast response of power electronic components, the photovoltaic (PV) inverter can cope with the intermittent and uncertainty of power generation due to weather changes. Therefore, this paper proposes a cooperative voltage control scheme to solve the voltage problems associated with high PV penetration. The scheme is developed based on a multi-agent system (MAS) with a distributed control architecture using time coordination between voltage regulators and reactive power control of the PV inverters. The scheme's objective is to minimize voltage deviations and reduce the stress on the traditional voltage control devices by utilizing the available reactive power of the PV inverters. Different simulations are carried out and analyzed for various operating conditions over 24 hours using the IEEE 34-bus and 123-bus test feeders. The simulation results show that the proposed control scheme can successfully reduce the total voltage deviation and decrease the number of tap operations of voltage regulators at different sun profiles. INDEX TERMS Distributed control, multi-agent, photovoltaic, unbalanced systems, voltage deviations.