Distributed Nodal Voltage Regulation Method for Low-Voltage Distribution Networks by Sharing PV System Reactive Power

Abstract

With the intensive integration of photovoltaic (PV) sources into the low-voltage distribution networks (LVDN), the nodal voltage limit violations and fluctuation problem cause concerns on the safety operation of a power system. The intermittent, stochastic, and fluctuating characteristics of PV output power leads to the frequent and fast fluctuation of nodal voltages. To address the voltage limit violation and fluctuation problem, this paper proposes a distributed nodal voltage regulation method based on photovoltaic reactive power and on-load tap changer transformers (OLTC). Using the local Q/V (Volt/Var) feedback controller derived from the grid sensitivity matrix, the voltage magnitude information is adopted to adjust the output of PV systems. Moreover, in order to share the burden of voltage regulation among distributed PV systems, a weighted distributed reactive power sharing algorithm is designed to achieve the voltage regulation according to the rated reactive power. Theoretical analysis is provided to show the convergence of the proposed algorithm. Additionally, the coordination strategy for distributed PV systems and OLTC is provided to reduce the reactive power outputs of PV systems. Five simulation case studies are designed to show the effectiveness of the proposed voltage regulation strategy, where the voltage regulation and proportional reactive power sharing can be achieved simultaneously.

Forecasting of Energy Balance in Prosumer Micro-Installations Using Machine Learning Models

“…In turn, Tables 10 and 12 show the results of the model evaluation for the exogenous scenario. The results of forecasting the balance (5) registered in November 2023 in the prosumer micro-installation using the random forest model ( 2 Tables [13][14][15][16] summarize the values of the forecasting accuracy measures on the test data and the values of the hyperparameters n est , D max , and number of lags l for the random forest model. In addition, the tables present the values of the F max parameter for the decision on the maximum number of features taken into account during the learning of trees.…”

“…In the case of very good insolation, the operation of individual prosumer (PV) installations is combined, and therefore, too much power (P, Q) is sent to the distribution network. Such a transmission causes additional losses of power and energy, as indicated by the authors of [15][16][17][18] in their publications.…”

“…For the LASSO model, two values for the number of delays were adopted: l = 24, l = 36 and 300 hyperparameter values α ranging from 10 −5 to 10 1 , as a result of which 600 models were created. For the random forest model, we utilized l = 24, l = 36 and 15 tree count values (n est ∈ [10, 500]), resulting in 15 values for the maximum depth of the tree (D max ∈ [5,15]). In addition, the models were tested for three parameter values, with F max determining the maximum number of features taken into account during the learning of trees.…”

A Hierarchical Multi-Stage Coordination of Inverters for Voltage Control in Active Distribution Networks with a µPMU-PDC

“…In the area of control algorithms, there have been several research studies on the coordinated operation of DERs with other voltage regulation devices, such as on-load tap changers (OLTC) and capacitor banks, to enhance the flexibility of a voltage regulation system [4]. One such approach is a two-stage online algorithm proposed in [5], which employs DERs as a complementary solution to control the voltage violation problem.…”

Integration of PV Sources in Prosumer Installations Eliminating Their Negative Impact on the Supplying Grid and Optimizing the Microgrid Operation

“…In the first case, the reactive power is a function of its active power, whereas in the Q-U strategy it depends on the voltage measured at the point of common coupling (PCC). The increase in reactive power drawn from the network results in mitigation of the voltage rise at the PCC [14,15]. However, it should be emphasized that many PV inverters operate with cosϕ = 1, so the range of change of reactive power is limited by the total current carrying capacity and may be relatively small in practice.…”