Modified STATCOM control strategy for fault ride-through capability enhancement of grid-connected PV/wind hybrid power system during voltage sag

Abstract

This paper proposes the employment of Static Synchronous Compensator (STATCOM) in reactive power compensation to enhance the Fault Ride-Through (FRT) capability and improve the dynamic performance of a grid-connected PV/wind hybrid power system during the transient grid disturbances. The hybrid power system consisting of 9 MW Doubly Fed Induction Generator (DFIG)-based wind farm and 1 MW PV station is integrated with 100 MVAR STATCOM at the Point of Common Coupling (PCC) bus. The dynamic performance of the PV/wind hybrid power system with the proposed STAT-COM controller is analyzed and compared with another FRT control strategy during a grid voltage sag. The FRT control strategy is based on the injection of reactive power from the hybrid system to enhance the FRT capability during the grid faults, and also activation of the outer crowbar protection system to protect the DFIG. On the other hand, the proposed STATCOM controller adjusts the PCC bus voltage during the grid disturbances by dynamically controlling the amount of reactive power injected to or absorbed from the electrical grid. Modeling and simulation of the proposed hybrid power system have been implemented using MATLAB/SIMULINK software. The effectiveness of both the proposed STATCOM controller and the FRT control strategy is evaluated during a 50% grid voltage sag. The simulation results illustrate that the STATCOM controller decreases significantly the level of voltage drop during the voltage sag, maintains the injected active power from the PV station at its rated value, and protects effectively the PV DC-link voltage from overvoltage. Moreover, when the STATCOM controller is employed, the injected active power from the wind farm is improved considerably and the oscillations of the DFIG rotor speed are reduced efficiently during the fault. Furthermore, the comparison confirms the superior dynamic performance of the STATCOM controller in enhancement the FRT capability as compared with the FRT control strategy.

STATCOM Controller Tuning to Enhance LVRT Capability of Grid-Connected Wind Power Generating Plants

“…In addition, low voltage at the PCC reduces the capacity of the GSC to transfer active power to the grid. is leads to excess power in the DC link capacitor, resulting in increased DC link voltage [25,28].…”

“…us, the fundamental component of V st is proportional to V dc . VSI controller operation starts with a measurement system which obtains DC capacitor voltage V dc , STATCOM reactive current I abc , and bus line voltage V g,abc [28,35], as shown in Figure 5.…”

“…α is the phase shift of STATCOM voltage (V st ) with respect to the grid voltage (V g ). e positive and negative voltages of the DC capacitor are maintained equal using offset (Δα) from the DC voltage regulator [28,35].…”

A review ofSTATCOMcontrol for stability enhancement of power systems with wind/PVpenetration: Existing research and future scope

“…For a hybrid power system in which PV and wind plants are integrated through a common DC bus, a PI‐STATCOM can be employed to improve the voltage profile of the load bus 80 . Hamdan et al 81 proposed a modified STATCOM controller to increase the dynamic performance and lower the voltage dips. The authors of References 82 and 83 adopt an eigen‐structure assignment approach for enhancing system stability.…”

Optimal Shunt-Resonance Fault Current Limiter for Transient Stability Enhancement of a Grid-Connected Hybrid PV/Wind Power System

“…The study concerned to improve the system dynamic performance in the post-fault duration and the simulation results confirmed the superior impact of the STATCOM compared with the Static Var Compesnasator (SVC) when subjected to 3LG fault at different locations in the grid. In [15], the paper presented the utilization of STATCOM in reactive power compensation to enhance the dynamic behavior for a grid-tied hybrid PV/wind energy system under the fault events. The results validated the effectiveness of the STATCOM controller in improving the transient stability compared with the conventional FRT control scheme when a severe three-phase grid voltage sag occurs.…”