Point of common coupling (PCC) voltage control of a grid-connected solar photovoltaic (PV) system

Abstract

In future low voltage grids, with multiple inverter interfaced sources connected, voltage regulation may become a necessary task. The potential exists for inverter interfaced sources to be deployed to regulate the voltage at the point of common coupling (PCC) of each inverter interfaced sources. The PCC voltage regulation is attainable with inverter interfaced sources by dynamically controlling the amount of reactive power injected to the power distribution grid by individual systems. In the current research, a closed-loop controller is proposed to regulate the PCC voltage of a solar photovoltaic (PV) system that is connected to a single-phase power distribution feeder (with R to X ratio greater than 1). The plant model of the PCC voltage controller of the PV system is derived considering both reactance and resistance of the network to which the PV system is connected. Three different compensators are evaluated to identify a suitable compensator for the closed-loop PCC voltage controller to regulate the PCC voltage at a given reference voltage. Simulation studies and experimental verification confirm that the theoretical approach taken to derive the control plant model of the PCC voltage controller is accurate and the procedure that is followed to design the controller is robust. The control design procedures illustrated in the current research leads to a PCC voltage control system with acceptable dynamic and steady state performance. 2013 IEEE.

Advanced point of common coupling voltage controllers for grid-connected solar photovoltaic (PV) systems

“…Hence an opportunity exists to regulate the PCC voltage by dynamically regulating the active and reactive power response of the PV system. The closed-loop PCC voltage controller that dynamically controls the reactive power response of the PV system (herein after referred to as the PCC V Q controller) described in detail in [17] is summarised in this Section.…”

“…The control plant model of the PCC V Q controller, G V gQ (s) can be derived as given in (1) [17]. The plant model is derived by applying a time discriminated decoupling mechanism as suggested in [18] to decouple the PCC V Q controller from the rest of the control system of the PV system.…”

“…Further, the gain of the integrator, k pq , as shown in Fig. 3(a), can be determined to achieve the steady-state of the PCC V Q controller within a suitable time delay using the reference grid impedance as mentioned in Section 2, assuming G cc (s) = 1 [17]. In this case, 1 s was chosen as the settling time.…”

“…In the PV system, the active power flow is controlled by the DC-link voltage controller and the current controller. The accurate command tracking of the control system of the PV system and also decoupling of control systems (as suggested in [18]) where applicable are realised by properly selecting the response time of the controllers [17], [19]. Similarly, the response time of the PCC V P controller is discriminated in order to decouple the controller from the rest of the control system that is associated in active power transfer of the PV system.…”

Microgrid energy management system control strategy

“…A connected microgrid is defined as a grid that is connected to a utility grid at a static switch called the point of common coupling (PCC), and cooperates with the utility grid by adjusting the power balance of the utility grid in terms of facilitating the import/export of power. On the other hand, a stand-alone micro grid is referred to as an isolated grid which is disconnected from the utility grid at the PCC, and operates autonomously[II], [12].…”