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This paper presents an improved particle swarm optimization algorithm (IPSO) to optimal reactive power dispatch and voltage control of power system. The improved particle swarm optimization algorithm introduces the adaptive inertia factor into the classical swarm algorithm to improve the global search capability and accelerate the searching speed. Study the DPSO algorithm to construct the collection...
The traditional control strategies of the permanent magnet synchronous generator (PMSG) based on rotor flux orientation have unconquerable drawbacks, such as the reactive power exchange by the id=0 control and the complicated calculation by the unity power factor (UPF) control. A novel UPF control strategy of the PMSG using stator flux orientation is proposed in this paper. The simulation results...
This paper researched the necessity and feasibility for installing dynamic reactive power compensation device STATCOM in wind energy collection substation with the aim of illuminating the validity of the compensator and selecting of the compensation devices with the integration of the large scale wind farms. According to simulation results, this paper checking its function for improving electrical...
A search strategy for identifying chains of events during power system cascading failure is proposed in this paper. This strategy corresponds to the study of overload of power lines and protective relaying hidden failures. By applying optimal power flow (OPF) technique to implement the optimal active and reactive power dispatching, and accordingly reduce the load losses caused by cascading events...
The interior-point filter algorithm (IPFA) is based on a primal-dual interior-point algorithm with a filter set which can be updated after every iteration, and the algorithm will not cycle between two points that alternately decrease the constraint violation and the barrier objective function. The simulation results from IEEE 30-bus system, IEEE 57-bus system and IEEE 118-bus system show that using...
Wind generation has been the fastest growing power source over the past decade and this growth is forecasted to continue. Grid code requirements on wind power plant are becoming more stringent as the wind power penetration level increases. In order to identify the risk of incompliant with grid code requirements at the planning stage of a wind power plant project, a standard grid code study process...
The fast development of wind power generation brings new necessary requirement for wind turbine to provide Low Voltage Ride-Through (LVRT) capability. The paper introduces the models of Doubly Fed Induction Generator (DFIG), converter and rotor active crowbar, and analyses characteristics of DFIG system with rotor active crowbar during grid voltage dip. A novel turn-on and turn-off control method...
This paper presents an improved Newton Raphson load flow algorithm considering distributed generation (DG) based on their control strategies. Different control strategies for various DGs are firstly investigated and the load flow model for direct-driven wind generator is especially mentioned. Then, each kind of DGs, including photovoltaic, wind turbine, fuel cell and microturbine, is assigned a bus...
This paper presents the relevant aspects related to large scale integration of wind power into the power system. Grid integration of WPPs is a technical and economic ability of WPPs to connect and operate within the electric power supply network in a manner which is compatible with the day-to-day operation and short-term security of the electric supply as a whole. WPPs when connected to a weak grid...
This study proposes an islanding detection method for use of grid-connected inverter of distributed renewable generation system. The proposed method is based on two indices: the rate of change of voltage (ROCOV) and the rate of change of frequency (ROCOF). When an inverter is grid-connected, the ROCOV and ROCOF are lower than the threshold values. In contrast, as an islanding occurs, the ROCOV or...
The induction generators are basic to wind energy conversion. They produce the active power and consume reactive power, with the voltage characteristics fragile compared with that of the synchronous generators. In stressed system conditions, they may intensify var imbalance, causing undesirable operation of the zone 3 impedance relays (mho relays). In this paper, the static voltage characteristics...
This article uses the BEM electromagnetic field calculation way to simulate the internal electric field distribution of shunt reactor, and discusses the internal electric field impact of reactor about shunt reactor sealed surface insulation cracking and the installation position of multi-tap arc-suppression coil. Simulation results show that sealed surface crack is not only easy to cause the sealed...
According to the theory of Voltage Source Converter (VSC) can control active power and reactive power simultaneously and independently, back-to-back VSC is applied to the synchronous parallel operation in power grids. Combined with the characteristic of UPFC circuit structure, this paper proposes a new scheme based on power transmission which can realize integrated functions of power system synchronization...
Solid oxide fuel cells (SOFCs) are modular and flexible in relation to the fuel in use, and have the capability to be used for combined heat and power applications at high efficiency. Due to the advantages, SOFCs are emerging as an attractive energy generation option. As a generation resource, SOFCs could be used as a distributed one connected with a large power system and also could be planted in...
To solve the problems of voltage fluctuation, flicker, harmonic and long distance transmission caused by offshore large scale wind farm (WF), a wind power integration scheme by using VSC-HVDC system has been proposed. The WF's voltage has kept in stable by the VSC-HVDC system's reactive power control in real time. There is little low-order harmonics and voltage fluctuation because the power has transmitted...
The EMTDC model of ±500kV Gao-Zhao HVDC with DC power forth-and-reverse transmission deicing function is firstly introduced, including model parameters, user-defined SIMADYN D module development and HVDC control strategies, then bipole DC power forth-and-reverse transmission theory, deicing function realization and deicing function operation procedure are presented successively, and finally some deep...
This article uses ATP-EMTP software platform to analyze the electromagnetic transient process of the reactive power compensation system. Simulation results show that the closing surge of inputing capacitor and the reignition overvoltage are the most serious damage on the system electromagnetic transient process. This article also discussed the renewed measures on the reignition overvoltage and calculated...
In this paper self-excitation phenomena which may occur in no-load generator with a long line is investigated. With the analysis of the physical process of self excitation and adoption the Π-type equivalent model for the line, the effect of frequency on self-excitation is evaluated, and an expression of self-excitation at the critical frequency is proposed. Note that systems may experience transition...
The passive control method that apply the passive power filter (PPF) to suppress negative effect of the Thyristor Switched Capacitor (TSC) is given in this paper, in order to improve zero-crossing voltage detection algorithm of controller of TSC. The study aims to suppress transient surge of reactive power induced by the TSC to a point of common coupling (PCC) of the power distribution system. In...
This paper studied mathematical model of doubly-fed induction generator (DFIG) based wind turbine generation system under unbalanced voltage. A dual-PI current control strategy was proposed to improve the performance of DFIG's rotor side convert (RSC) under asymmetrical voltage condition. The symmetrical component theory is employed to decompose asymmetrical three-phase variable such as voltage and...
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