A Communicationless PCC Voltage Compensation Using an Improved Droop Control Scheme in Islanding Microgrids

Abstract

This paper proposes a point of common coupling (PCC) voltage compensation method for islanding microgrids using an improved power sharing control scheme among distributed generators (DGs) without communication. The PCC voltage compensation algorithm is implemented in the droop control scheme to reduce the PCC voltage deviation produced by the droop controller itself and the voltage drop on the line impedance. The control scheme of each individual DG unit is designed to use only locally measured feedback variables and an obtained line impedance to calculate the PCC voltage. Therefore, traditional voltage measurement devices installed at the PCC as well as communication between the PCC and the DGs are not required. The proposed control scheme can maintain the PCC voltage amplitude within an allowed range even to some extent assuming inaccurate line impedance parameters. In addition, it can achieve proper power sharing in islanding microgrids. Experimental results obtained under accurate and inaccurate line impedances are presented to show the performance of the proposed control scheme in islanding microgrids.

Communication-Less Primary and Secondary Control in Inverter-Interfaced AC Microgrid: An Overview

“…A voltage compensation technique is adapted for PCC voltage restoration in an islanded AC MG [100]. The droop control for power sharing is improved with compensation algorithm, so that communication links are not required for this kind of restoration process.…”

“…Unscented Kalman filter based state estimation [97] considered not discussed not discussed not discussed Secondary droop + rate limiter [98] not discussed not discussed not discussed not discussed Under frequency load shedding Tech. [99] not discussed not discussed not discussed (R/X) < 1 Line impedance drop based compensation [100] not discussed not discussed not discussed both (R/X) >1 and <1 Ramp control of load power [101] not discussed not discussed not discussed not discussed Coordination control between battery, PV and TCL [102] The droop controllers considered for simulation are: Droop 1: Linear active power-frequency droops with linear reactive power-voltage droop [47] Droop 2: Arctan power-frequency droops with linear reactive power-voltage droop [58] Droop 3: Linear power-angle droops with linear reactive power-voltage droop [50] Droop 4: Linear power-frequency droop with virtual impedance compensated linear reactive power-voltage droop [68] Droop 5: Linear power-frequency droop with linear Q-V dot droop [62] The droop coefficients were designed to have allowable voltage droop in the system of 5% and an allowable frequency droop as 0.5%. Care was taken to keep these design goals same for all the droop controllers to have a uniform comparison.…”

Performance Improvement of Dual-Buck Inverter With Mitigating Reverse Recovery Characteristics and Supporting Reactive Power

“…As the penetration of the distributed generation (DG) into the distribution networks continues to increase, the DGs are required to participate in the grid stability control [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15]. One of the requirements is the low voltage ride through [1][2][3][4][5].…”

“…In case of a grid fault, the DGs should be connected to the grid for the specified voltage and time, and then inject the reactive power to support the grid. Another important role is the point of common coupling (PCC) voltage regulation [6][7][8][9][10][11][12][13][14][15]. The DGs lead bidirectional power flow in the distribution networks.…”

Multiobjective Particle Swarm Optimization for Microgrids Pareto Optimization Dispatch

“…e implementation of multiobjective optimization (MOO) dispatch for microgrids (MGs), which consist of distributed generations (DGs), load systems, storages, and communication systems, can help maximize the benefits while mitigating the negative impacts of DGs on power grids. e MG can operate in both islanded [4][5][6] and gridconnected modes [7][8][9][10][11]. It is able to improve the stability and reliability of power supply in factory [8], residential districts [9][10][11], and military zone [12].…”