A Coordinated Voltage Regulation Algorithm of a Power Distribution Grid with Multiple Photovoltaic Distributed Generators Based on Active Power Curtailment and On-Line Tap Changer

Abstract

The aim of this research is to manage the voltage of an active distribution grid with a low X/R ratio and multiple Photovoltaic Distributed Generators (PVDGs) operating under varying conditions. This is achieved by providing a methodology for coordinating three voltage-based controllers implementing an Adaptive Neuro-Fuzzy Inference System (ANFIS). The first controller is for the On-Line Tap Changer (OLTC), which computes its adequate voltage reference. Whereas the second determines the required Active Power Curtailment (APC) setpoint for PVDG units with the aim of regulating the voltage magnitude and preventing continuous tap operation (the hunting problem) of OLTC. Finally, the last component is an auxiliary controller designed for reactive power adjustment. Its function is to manage voltage at the Common Coupling Point (CCP) within the network. This regulation not only aids in preventing undue stress on the OLTC but also contributes to a modest reduction in active power generated by PVDGs. The algorithm coordinating between these three controllers is simulated in MATLAB/SIMULINK and tested on a modified IEEE 33-bus power distribution grid (PDG). The results revealed the efficacy of the adopted algorithm in regulating voltage magnitudes in all buses compared to the traditional control method.

A Review of Voltage Control Studies on Low Voltage Distribution Networks Containing High Penetration Distributed Photovoltaics

“…Yuan et al [45] analyze the principle of the double-core symmetrical phase-shifting transformer (DS-PST) and the application of trend regulation, which can transfer the active power transmitted by high load-rate lines to low load-rate lines so as to make the distribution of system trend more balanced and effectively improve the transmission capacity of the power system. Changing the control strategy of the on-load tap changer (OLTC), the first controller (ANFIS-OC) in this strategy solves the voltage overrun problem due to low X/R ratio and PV distributed generation by calculating the OLTC reference voltage based on the minimum and maximum voltage magnitude of the grid [46]. Tang et al [47] innovate the voltage control architecture for distribution networks by considering the modeling of the discrete control of on-load tap-changer transformers, which is applicable to the coordinated control of a fundamentally developed network, as well as to the optimization-based centralized control of a network with a fully articulated system.…”

A Fuzzy OLTC Controller: Applicability in the Transition Stage of the Energy System Transformation

“…Another method involves the active power curtailment of the DERs [7,8]. By decreasing P G , the overvoltage in the network connection point (NCP) is reduced.…”