Impedance-based method is an effective to analyze the system stability. Based on impedance stability theory, a doubly fed induction generator (DFIG) based wind power generation can be decoupled into positive- and negative-sequence subsystem. Then, under small-signal operation, each subsystem assumed have linear characteristic in frequency domain. Therefore, single-in-single-out criterion applied for of interconnected consisted DFIG grid. However, when there coupling system, this assumption...

With the increasing penetration of renewable energy, wind turbines based on doubly fed induction generators (DFIG) are becoming more and important in power system. The impedance reshaping control strategy virtual method can be utilized to solve stability problem DFIG-grid interconnected system under weak grid. However, issues caused by phase-locked loop (PLL) is complicated due frequency coupling characteristic. This article presents an improved DFIG a symmetrical PLL, which characteristic...

With high renewable power penetration, uncertainty and intermittence of sources become major concerns system planning operation. Large fast wind speed change may cause great variation active generation, which lead to stability reliability problems. The response speeds the committed conventional generators (CGs) for frequency regulations are critical reliable stable slow CGs result in shortage or surplus, affect frequency. This paper proposes a technique evaluate operational efficiency...

Recent advances in rheocasting have resulted significant expansion the types of products currently full commercial production. The current paper gives an overview components production Europe and China produced using RheoMetal TM process, that has taken lead a strong drive towards new heavy-duty applications made from aluminium alloys. In China, dominating are found telecom industry. trend is more marine automotive commonly fatigue loaded applications. reason for choice complicated shape...

Energy storage system (ESS) has been widely used in photovoltaic to ensure stable power generation. This article proposes a flying capacitor bidirectional buck–boost converter (FCBBC), aiming at making the ESS work with four quadrant wide dc+bus voltage variation condition. With symmetrical modulation strategy, proposed FCBBC can achieve seamless switching between buck and boost mode match changes energy dc bus side. Meanwhile, considering application requirements, fixed frequency model...

Owing to intermittency of wind power and slow ramp rates conventional generators, a considerable amount energy cannot be effectively utilized during frequency control processes. This paper proposes technique for system planners operators select or commit capacity battery storage (BESS) mitigating the effects intermittent speeds on reliability economics. A novel procedure is proposed determine based chaos theory intermittency-related parameters. The frequency-related economic indices with...

Summary In this work, we present a transformation‐based adaptive control design, for uncertain strict‐feedback nonlinear systems, to achieve given performance specifications in terms of convergence rate/time, overshoot, steady‐state (zero‐error) precision, addition the primary stability requirement. For case with no uncertainty and known coefficient, by introducing time‐varying scaling function an error‐dependent transformation, develop strategy that is able exponential uniform tracking...

This paper proposes a modified self-synchronized synchronverter for unbalanced power grids. Small signal analysis of the conventional shows that its stability margin around 50 Hz is very limited. Thus, ripples will be caused at frequency Hz. Filter- based current feeding loops are adopted in order to enhance and eliminate ripples. In addition, characteristics grids analyzed, an improved strategy using resonant controller proposed restrain harmonics The parameter design also studied...

A novel efficient and entirely green hybrid energy conversion system comprising compressed air storage Kalina KCS11 is proposed for peak shaving application grid stability. The use of high-temperature thermal as a replacement the traditional combustion chamber with clean working fluid aims to minimize greenhouse gas emissions while adequately addressing intermittency electricity curtailment power grids high penetration renewable sources. comprehensively analyzed from energy, exergy, economic...

The impedance‐based analysis is widely used to study stability problem between wind turbine system and grid network. Stationary sequence domain impedance has advantages over synchronous dq due its easy measurement in practical application. However, there frequency coupling effect impedance, a 2×2 matrix needed which makes the be multiple‐input–multiple‐output system, controller tuning much more complex compared with single‐input–single‐output (SISO) system. In this study, model of doubly fed...

A maintenance interval optimization model for wind turbine gearbox considering the maximization component profit per unit time was presented in this paper. First, principle and configuration of were introduced, failure characteristic is analyzed as well rate distribution components gearbox. Then, concept income coefficient λ element utilizing U ( t ) given. describes proportion that takes up total electric power sale，and represents average to sale during 0~ . Based on above two concepts...

Fatigue and destruction in the shafts of a wind turbine caused by sub-synchronous oscillations during power system faults is critical for reliability. This paper investigates three-mass shaft model according to MW class doubly-fed generator mechanical structure obtains electromagnetic torque PSCAD simulation when oscillation occurred system. The equivalent load spectrum obtained via rain flow counting method. finite element gear set up Solidworks software. And then it meshed ANSYS software...

AC and DC hybrid distribution network detailed modelling multi-operation conditions of the simulation analysis will effectively support project reliable stable operation. However, at present, large-scale system-level AC–DC based on flexible is lack timeliness practicability. Based real-time digital platform RT-LAB, ACDC model established, which includes ±20 kV interconnection system, distributed photovoltaic, wind power, energy storage electric vehicle corresponding converter control...

This paper proposed a study on the power dispatching optimization in microgrid aiming at Chinese national condition based PSO algorithm. The whole work is basis of weighted factor variation objective function due to different weather conditions. Three cases including good contamination-diffusing condition, smog and normal are considered, respectively. In case weather, new energy generation battery system will be all out use as less possible from primary grid so that pollution produced by...

In an autonomous micro grid or a power system with high renewable penetration, the intermittency of energy resources becomes major concern operation. Dynamic process frequency response and control due to unit failures resource variation may have significant impacts on operational reliability because outputs committed conventional generators be frequently adjusted for recovery. This paper proposes technique investigate from aspect control. The time durations primary secondary controls are...

A micro-grid system based on a source dual active bridge (DAB) converter connected with load buck-boost DC/DC and DC/AC by the common DC-link is studied in this paper, which widely investigated yield of intelligent distribution microgrid. As power transmission hub, stability voltage plays key role normal operation whole system, affects stable back-stage inverters as well supply loads. The problem may occur at low frequency, if impedance characteristic DAB incompatible converters, will be...

In the treatise of Compensation Theory Unbalance Structure Athlete's Performance Ability, "some range" show restricts conditions in usage. By founding two types "cask model" on border condition, considering what structure is unbalanced and how compensation sides range". The new concept index can take affection quantify compensation. establishment individual model favor carries out respectively training. get up judge athletic ability type, illuminate complementary relationships weather...

To solve the random, intermittent, and unpredictable problems of clean energy utilization, storage is considered to be a better solution at present. Due characteristics large instantaneous power, high density, fast charging discharging speed, flywheel currently occupies an important position in new storage. In this paper, dual-three-phase permanent magnet synchronous motor introduced into system output higher power smaller current harmonics lower bus voltage. A model established,...

Wind turbines are complex and expensive equipment, requiring high reliability low maintenance costs. However, most of the existing fault tree analysis (FTA) methods for wind assume that repair can restore them to as good new condition, which is called perfect repair. This assumption may not be realistic in practice, fully recover original performance or functionality equipment introduce defects errors. phenomenon imperfect repair, reduce over time. To consider effect analysis, we present a...