Phase Balancing and Reactive Power Support Services for Microgrids

Abstract

Alternating current (AC) microgrids are expected to operate as active components within smart distribution grids in the near future. The high penetration of intermittent renewable energy sources and the rapid electrification of the thermal and transportation sectors pose serious challenges that must be addressed by modern distribution system operators. Hence, new solutions should be developed to overcome these issues. Microgrids can be considered as a great candidate for the provision of ancillary services since they are more flexible to coordinate their distributed generation sources and their loads. This paper proposes a method for compensating microgrid power factor and loads asymmetries by utilizing advanced functionalities enabled by grid tied inverters of photovoltaics and energy storage systems. Further, a central controller has been developed for adaptively regulating the provision of both reactive power and phase balancing services according to the measured loading conditions at the microgrid’s point of common coupling. An experimental validation with a laboratory scale inverter and a real time hardware in the loop investigation demonstrates that the provision of such ancillary services by the microgrid can significantly improve the operation of distribution grids in terms of power quality, energy losses and utilization of available capacity.

Improving the Efficiency and Sustainability of Power Systems Using Distributed Power Factor Correction Methods

“…In addition, the MODBUS protocol could also read data on the network (voltages, currents, powers, phases, total harmonic distortion (THD), etc.). Starting from formula (19), the THD is here calculated based on another equivalent consecrated formula (44), where the current was measured and I RMS easily computed, and the fundamental harmonic was calculated using Fast Fourier Transform (FFT).…”

“…In the context of increasing the penetration of the intermittent renewable energy sources, the concept of microgrids (MG) becomes more frequent as a solution to these issues. There are efforts being made to improve the solutions available to microgrid developers in order to compensate the power factor and the load asymmetries inside the microgrid by utilizing advanced functionalities enabled by grid tied inverters of photovoltaics and energy storage systems [18,19].…”

“…Advanced operational capabilities of power electronic based distributed energy resources (DERs) can be employed to compensate power quality phenomena such as harmonics, interharmonics, and current/voltage unbalances [15,[19][20][21][22]. Hence, smart and multi-functional inverters are capable of providing multiple ancillary services to the MG, along with dedicated resources such as automatic power factor correction equipment.…”

A Novel Control Strategy to Active Power Filter with Load Voltage Support Considering Current Harmonic Compensation

“…Since the AC source should not generate the pulsating current due to the safety and lifetime procedures, the sinusoidal current waveform is just allowed to be injected to the grid according to power quality standards. Therefore, the non-linearity components of the required current are supplied by the AFP [15][16][17][18]. In order to decrease the output voltage ripples using only passive filters, the switching frequency is increased, which results in incremental switching losses a reduction in the system's efficiency.…”

A Study on the Improvement of Parallel Operation Characteristics of DC/DC Converter Using Improved Full-Duplex Communication Hardware

“…In addition, the load-sharing experiment of the power converter with the proposed communication hardware confirmed that a stable parallel operation was performed. Figure 1 shows the equivalent circuit for analyzing the power-sharing characteristics of n parallel connected power converters [15]. In Figure 1, V 1 to V n are the initial setting output voltage of number of n power converters, with each power converter having the same value.…”