Comparative study of reactive power control methods for photovoltaic inverters in low‐voltage grids

Abstract

The increasing installation of photovoltaic panels in low-voltage grids causes an over voltage problem, especially during high production and low consumption periods. Generally the over voltage problem is overcome by implementing reactive power control methods. The advances in networked control systems theory and practice create new scenarios where reactive power control methods can offer additional features and benefits. To explore these new capabilities, this study presents two new reactive power control methods that exploit the networked approach. These two methods are evaluated in a comparative reference framework that also includes the base-line case where no reactive control method is applied, the conventional droop method approach, and a solution based on a near-optimal location of a high power STATCOM derived from one of the new proposed networked methods. The main merit factors used to compare the control methods are the maximum voltage across the distribution grid, the power factor in the point of common coupling, and the total power losses and economic cost of the installation. With these merit factors, the advantages and limitations of the new and existing control methods are revealed and discussed. A useful discussion for selecting the best control solution is also reported.

Performance Evaluation of Secondary Control Policies with Respect to Digital Communications Properties in Inverter-based Islanded Microgrids

“…However, looking at the voltage, diverse control objectives may be considered because a standard policy specifying the MG voltage management is lacking. See [33] for a review and evaluation of different policies for secondary voltage control, where a common set of metrics was defined to asses pros and cons of the existing results that meet different goals. Hence, the comparative performance evaluation presented in this paper focuses only on frequency secondary control policies with a double control objective: active power sharing and frequency restoration.…”

Coordinated control of multifunctional inverters for voltage support and harmonic compensation in a grid-connected microgrid

“…The DG interfacing inverters can contribute in voltage support [2][3][4][5][6][7][8][9][10][11][12][13] and harmonic compensation [12][13][14][15][16][17][18][19][20][21] of Microgrids (MGs) and utility grids. These inverters known as multifunctional inverters inject power to the grid and the remaining capacity of the inverter can be dedicated to voltage support and power quality enhancement [10].…”

“…The power curtailment algorithms of [4] and [5] are based on local measurement and communication system, respectively. In [6], different reactive power methods for DG units are studied. The reactive power control approaches in [6] can be classified into distributed and central controller based schemes.…”

“…In [6], different reactive power methods for DG units are studied. The reactive power control approaches in [6] can be classified into distributed and central controller based schemes. The reactive power control of DG interfacing inverters is also studied in [7].…”

Flexible operation of parallel grid-connecting converters under unbalanced grid voltage

“…In order to limit the output current and reduce active power oscillation, [5][6][7][8][9][10][11][12][13][14][15][16] have investigated various control strategies, among which [12] ensures the minimum peak current values of injected current, but harmonic current was increased to meet the objective, leading to overcurrent. Although in [10] and [12] control strategies are developed to avoid overcurrent tripping, these strategies are only related to reactive power delivery under unbalanced grid and result in active and reactive power oscillation.…”