scholarly journals Transient Stability Enhancement of a Grid-Connected Large-Scale PV System Using Fuzzy Logic Controller

Electronics ◽  
2021 ◽  
Vol 10 (19) ◽  
pp. 2437
Author(s):  
Md. Rifat Hazari ◽  
Effat Jahan ◽  
Mohammad Abdul Mannan ◽  
Narottam Das

This paper presents a new intelligent control strategy to augment the low-voltage ride-through (LVRT) potential of photovoltaic (PV) plants, and the transient stability of a complete grid system. Modern grid codes demand that a PV plant should be connected to the main power system during network disturbance, providing voltage support. Therefore, in this paper, a novel fuzzy logic controller (FLC) using the controlled cascaded strategy is proposed for the grid side converter (GSC) of a PV plant to guarantee voltage recovery. The proposed FLC offers variable gains based upon the system requirements, which can inject a useful amount of reactive power after a severe network disturbance. Therefore, the terminal voltage dip will be low, restoring its pre-fault value and resuming its operation quickly. To make it realistic, the PV system is linked to the well-known IEEE nine bus system. Comparative analysis is shown—using power system computer-aided design/electromagnetic transients including DC (PSCAD/EMTDC) software—between the conventional proportional–integral (PI) controller-based cascaded strategy and the proposed control strategy to authenticate the usefulness of the proposed strategy. The comparative simulation results indicate that the transient stability and the LVRT capability of a grid-tied PV system can be augmented against severe fault using the proposed FLC-based cascaded GSC controller.

2013 ◽  
Vol 385-386 ◽  
pp. 1082-1085 ◽  
Author(s):  
Yan Juan Wu ◽  
Lin Chuan Li ◽  
Fang Zhang

In view of a serious threat for the transient stability of the power system being caused by the large-scale wind farms integration, and combining with advantages of STATCOM which can quickly restore the fault voltage and fastly, flexibly and smoothly compensate the reactive power, a method is proposed using STATCOM controller of to improve transient stability of the power system integrated by large-scale wind farms. The control strategy of the STATCOM controller uses adaptive double loop control. The role of the device to improvement transient stability of the power system is studied under the condition of serious fault. by simulation comparison with the condition without STATCOM controller installed at the same place. The simulation results show that the STATCOM controller can clearly improve transient stability of the power system integrated by large-scale wind farms.


Author(s):  
S Arockiaraj ◽  
BV Manikandan

In transmission line, the series compensation is used to improve stability and increases the power transmission capacity. It generates sub synchronous resonance (SSR) at turbine-generator shaft due to the interaction between the series compensation and wind turbine system. To solve this, several methods have been presented. However, these provide less performance during contingency period. Therefore, to mitigate the SSR and also to improve the dynamic performance of hybrid wind and PV system connected with series compensated wind farms, the adaptive technique of the Black Widow Optimization algorithm based Fuzzy Logic Controller (BWO-FLC) with UPFC is proposed in this paper. Here, the objective function is solved optimally using BWO technique. Based on this, the Fuzzy Logic Controller is designed. The results proved that the proposed controller performs the mitigation of SSR. The damping ratios of proposed controller to mitigation of SSR are 0.0098, 0.0139, and 0.0195 for wind speed of 6, 8 and 10 m/s respectively.


2012 ◽  
Vol 588-589 ◽  
pp. 574-577 ◽  
Author(s):  
Yan Juan Wu ◽  
Lin Chuan Li

Some faults will result wind turbine generators off-grid due to low grid voltage , furthermore, large-scale wind farms tripping can result in severe system oscillation and aggravate system transient instability . In view of this, static compensator (STATCOM) is installed in the grid containing large-scale wind farm. A voltage feedforward control strategy is proposed to adjust the reactive power of STATCOM compensation and ensure that the grid voltage is quickly restored to a safe range. The mathematical model of the doubly-fed induction wind generator (DFIG) is proposed. The control strategy of DFIG uses PI control for rotor angular velocity and active power. 4-machine system simulation results show that the STATCOM reactive power compensation significantly improve output active power of large-scale wind farm satisfying transient stability, reduce the probability of the tripping, and improve the utilization efficiency of wind farms.


Energies ◽  
2019 ◽  
Vol 12 (24) ◽  
pp. 4796 ◽  
Author(s):  
Eyad Radwan ◽  
Mutasim Nour ◽  
Emad Awada ◽  
Ali Baniyounes

This paper presents a control scheme for a photovoltaic (PV) system that uses a single-phase grid-connected inverter with low-voltage ride-through (LVRT) capability. In this scheme, two PI regulators are used to adjust the power angle and voltage modulation index of the inverter; therefore, controlling the inverter’s active and reactive output power, respectively. A fuzzy logic controller (FLC) is also implemented to manage the inverter’s operation during the LVRT operation. The FLC adjusts (or de-rates) the inverter’s reference active and reactive power commands based on the grid voltage sag and the power available from the PV system. Therefore, the inverter operation has been divided into two modes: (i) Maximum power point tracking (MPPT) during the normal operating conditions of the grid, and (ii) LVRT support when the grid is operating under faulty conditions. In the LVRT mode, the de-rating of the inverter active output power allows for injection of some reactive power, hence providing voltage support to the grid and enhancing the utilization factor of the inverter’s capacity. The proposed system was modelled and simulated using MATLAB Simulink. The simulation results showed good system performance in response to changes in reference power command, and in adjusting the amount of active and reactive power injected into the grid.


2013 ◽  
Vol 380-384 ◽  
pp. 3051-3056 ◽  
Author(s):  
Xiao Dan Wu ◽  
Wen Ying Liu

In this paper, starting from the active network loss formulas and wind characteristics, it is pointed out the reactive power loss and reactive flow is the major impact of wind power integration on power system loss. The reactive power loss formulas of box-type transformer, main step-up transformer, wind farm collector line and connecting grid line are analyzed. Next the reactive power loss of transformer and transmission line is described in detail. Then put forward the loss reduction measures that installing SVC on the low voltage side of the main step-up transformer and making the doubly-fed wind generators send out some reactive power at an allowed power factor. Use the case of Gansu Qiaodong wind farm to verify the effectiveness of the proposed measures.


2020 ◽  
Vol 10 (24) ◽  
pp. 8874
Author(s):  
Masaki Yagami ◽  
Masanori Ichinohe ◽  
Junji Tamura

This paper proposes a novel control method for enhancing transient stability by using renewable energy sources (RES). The kinetic energy accumulated in a rotor of variable speed wind generator (VSWG) is proactively used as the active power source, which is controlled according to the frequency measured at the wind farm. In addition, coordinated reactive power control according to the grid voltage is also carried out to more effectively use the kinetic energy of the VSWG. The effects of the proposed control system were evaluated by simulation analyses performed using a modified IEEE nine-bus power system network made up of synchronous generators (SGs), a photovoltaic (PV) system and a VSWG-based wind farm. Furthermore, the coordinated reactive power control between the VSWG and PV system was also demonstrated.


Energies ◽  
2018 ◽  
Vol 11 (8) ◽  
pp. 1995 ◽  
Author(s):  
Peng Shen ◽  
Lin Guan ◽  
Zhenlin Huang ◽  
Liang Wu ◽  
Zetao Jiang

This paper proposes an active-current control strategy for large-scale wind turbines (WTs) to improve the transient stability of power systems based on a perturbation estimation (PE) approach. The main idea of this control strategy is to mitigate the generator imbalance of mechanical and electrical powers by controlling the active-current of WTs. The effective mutual couplings of synchronous generators and WTs are identified using a Kron-reduction technique first. Then, the control object of each WT is assigned based on the identified mutual couplings. Finally, an individual controller is developed for each WT using a PE approach. In the control algorithm, a perturbation state (PS) is introduced for each WT to represent the comprehensive effect of the nonlinearities and parameter variations of the power system, and then it is estimated by a designed perturbation observer. The estimated PS is employed to compensate the actual perturbation, and to finally achieve the adaptive control design without requiring an accurate system model. The effectiveness of the proposed control approach on improving the system transient stability is validated in the modified IEEE 39-bus system.


2020 ◽  
Vol 182 ◽  
pp. 02011
Author(s):  
WAN Qian ◽  
Xia Chengjun ◽  
Azeddine Houari ◽  
Zhao Xue ◽  
Xia Chengjun ◽  
...  

Renewable energy sources (RESs) generally connected with electric power system via power electronic interface. This paper presents a reactive power and voltage (Q/V) control strategy of three-phase photovoltaic (PV) system to offering reactive power based on the typical dual-loop control topology. It is worth mentioning that control strategy can support reactive power when a low voltage fault occurs in AC bus without additional compensation device. With the help of the decoupling control, the PV array can generate active power as much as possible in variable external solar radiation conditions. The voltage of PV arrays is adopted as the objective, which on account of the easy availability and controllability of voltage, to control output active power. Besides, accurately modeling process from a PV cell to PV array is described in the beginning to acquire the P-V and V-I characteristics of PV arrays, which promote the designment of Q/V control.


2011 ◽  
Vol 48-49 ◽  
pp. 335-344
Author(s):  
Meng Zeng Cheng ◽  
Zhen Lan Dou ◽  
Xu Cai

In this paper, a control strategy for operation of rotor side converter (RSC) of Doubly Fed Induction Generators (DFIG) is developed by injecting reactive power into the grid in order to support the grid voltage during and after grid fault events. The novel nonlinear control method is based on differential geometry theory, and exact feedback linearization is applied for control system design of DFIG. Then the optimal control for the linearized system is obtained through introducing the linear quadratic regulator (LQR) design method. Simulation results on a single machine infinite bus power system show that the proposed nonlinear control method can inject reactive power to fault grid rapidly, reduce the oscillation of active power and improve the transient stability of power system.


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