Ensuring Stable Operation with Grid Codes: A Look at Canadian Wind Farm Interconnections

Summary The reactive power (var) dispatch is realized at the system and station levels. Var dispatch to the doubly fed induction generators (DFIGs) in the wind farm is seldom studied due to the difficulty of the number and modeling accuracy of the DFIGs and dependency of the var setting on its available reactive power capability (RPC). This paper proposes an optimization model to decide the incremental var output of the DFIGs in the wind farm. The object is to minimize the increments of active power loss in the wind farm and the deviation of the stator voltage of the DFIGs. Considering the voltage fluctuation at the PCC, the distribution coefficient of the var increment is defined for the DFIGs. The nonlinear constraints are expressed by the first + second‐order sensitivities of the active power loss of the wind farm and the stator voltages of the DFIGs to the var output of the DFIGs. The nondominated sorting genetic algorithm II (NSGA‐II) is applied to obtain the Pareto front, with the evaluation indicators of the var margin defined to decide the incremental var output of the DFIGs. The numerical results validate the feasibility of the proposed algorithm. The reactive power demand to the wind farm is distributed among the DFIGs satisfying the objects and the constraints with desirable accuracy and calculation efficiency.

Section: Introductionmentioning

confidence: 99%

Reactive power dispatch of DFIGs in wind farm based on multi‐object optimization

Zhang

et al. 2019

“…Due to the rapid integration of wind turbines (WTs) and wind power plants (WPPs) into electric power system, many concerns emerged related to the efficient, stable, and secure operation of the existing electric power system . Therefore, the transmission system operators have elaborated specific technical requirements in many countries for connecting the WPPs as grid code requirements . Low‐voltage ride‐through (LVRT) is one of the main grid code requirements for the integration of WPPs.…”

Section: Introductionmentioning

confidence: 99%

“…Low‐voltage ride‐through (LVRT) is one of the main grid code requirements for the integration of WPPs. Based on this requirement, WPPs should stay connected to the grid and inject reactive power to support the grid connecting point (GCP) voltage during fault …”

Section: Introductionmentioning

confidence: 99%

“…1,2 Therefore, the transmission system operators have elaborated specific technical requirements in many countries for connecting the WPPs as grid code requirements. 3 Low-voltage ride-through (LVRT) is one of the main grid code requirements for the integration of WPPs. Based on this requirement, WPPs should stay connected to the grid and inject reactive power to support the grid connecting point (GCP) voltage during fault.…”

Section: Introductionmentioning

confidence: 99%

“…Based on this requirement, WPPs should stay connected to the grid and inject reactive power to support the grid connecting point (GCP) voltage during fault. 3,4 LIST OF SYMBOLS AND ABBREVIATIONS: C p , power coefficient; C sh , CBFCL capacitor; D tg , damping constant; EMTDC, electromagnetic transient design and control; GCP, grid connecting point; GCR, grid code requirements; H g , generator inertia; H t , equivalent turbine-blade inertia; IGBT, insulatedgate bipolar transistor; i s , stator current; i r , rotor current; K tg , shaft stiffness constant; L d , DC reactor inductance; LI, limiting impedance; L m , magnetizing inductance; L s , stator inductance; LVRT, low-voltage ride-through; L r , rotor inductance; PAC, pitch angle control; PCC, point of common coupling; P m , mechanical power; PSCAD, power system computer aided design; R, blade radius; r d , DC reactor resistance; R r , rotor resistance; R s , stator resistance; R sh , CBFCL resistance; SCC, short circuit current; V g , grid Voltage; V r , rotor voltage; V s , stator voltage; V w , wind speed; WPP, wind power plant; WT, wind turbine; Z g , grid impedance; β, pitch angle; δ g , generator angle position; δ t , wind turbine shaft angle; λ, tip speed ratio; ω g , generator angular speed; ω t , turbine angular speed; ω s , stator angular frequency; ω r , rotor angular frequency; ψ r , rotor flux; ψ s , stator flux; ρ, air density On the other hand, direct grid connection of WPPs causes short circuit current (SCC) level surpass beyond capacities of existing equipment in some points of grid. This can damage the series existing equipment and can cause negative effect on WPPs with respect to stability.…”

Section: Introductionmentioning

confidence: 99%

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A modified capacitive bridge-type fault current limiter (CBFCL) for LVRT performance enhancement of wind power plants

Firouzi

2017

Summary Low‐voltage ride‐through (LVRT) is one of the main grid code requirements for integration of wind power plants (WPPs). This paper presents a capacitive bridge‐type fault current limiter (CBFCL) for LVRT performance enhancement of WPPs. The CBFCL is based on the conventional inductive bridge‐type fault current limiter (IBFCL), in which the limiting impedance of the IBFCL has been adapted according to WPPs environment to satisfy LVRT requirements. To show the efficiency of the CBFCL for LVRT performance enhancement, its capability is compared with the IBFCL. The WPP has been modeled by an equivalent aggregated squirrel‐cage induction generator. Simulations have been performed in PSCAD/EMTDC software. The simulation results reveal that the CBFCL is an effective and novel solution for LVRT performance enhancement and short circuit current limitation of WPPs. Also, it was found that the CBFCL is more competent to satisfy LVRT requirements than the IBFCL.

An outlook on endangering grid security in India due to implementation challenges of low voltage ride through protection in wind turbines

Amalorpavaraj

Prabaharan

Moursi

et al. 2020

The substantial increase in new integration of wind power has required changes in grid codes to ensure grid security. Providing low voltage ride through (LVRT) protection helps to sustain the transient conditions without tripping and supports its recovery post-fault. The grid codes for LVRT capability in countries with substantial wind capacity are surveyed in this paper. The challenges that arise, endangering the grid security due to the nonimplementation of these grid codes in the wind turbines (WT) which were preinstalled before the mandatory grid code was established is rarely a topic focused in literature. The LVRT capability requirement as per the wind turbine type classification is elucidated. The challenges due to enhancement and upgradation of technology include financial constraints for additional LVRT fittings, planning and renovation. Discussion and prognosis on the challenges provide direction for investigation and research. K E Y W O R D S fault ride-through, grid codes, Indian grid, Indian wind turbines, low voltage ride through, wind turbine type 1 | INTRODUCTION The significant growth in wind power, in large part to address environmental issues, has made wind energy an increasingly applied energy source. 1 With the expanding grid integration for wind power, network operators have to confirm that consumer power quality is not negotiated. The rigidness of the power system is being modified and advanced