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This paper introduces a shunt FACTS device for tapping and realizing power flow control in half-wavelength transmission lines. It is design to drain or inject power in the line, like a shunt HVAC Tap, as well as acts as a shunt FACTS device to control the main power flow through the half wavelength transmission line.
A method of quantitative contribution assessment of power source in critical branch is proposed in this paper. During the various operation modes, a branch must keep its power flow within the critical boundary. A simple branch model is given to represent the overhead line, cable or transformer. The index proximity of criticality (IPC) is formulated to evaluate the severity. An electrical decomposition...
DG based on wind energy system (WES) has the probabilistic output power relied on natural conditions, the traditional deterministic load flow is not a suitable tool for the analyzing and maintaining distribution system. Aiming at this problem, this paper applies a probabilistic power flow (PLF) method to evaluate the influence of distributed generation with WES. Firstly, the probabilistic model of...
DG based on Photovoltaic System Generation (PVS) has the probabilistic output power relied on natural conditions, the traditional deterministic load flow is not a suitable tool for the analyzing and maintaining distribution system. Aiming at this problem, this paper applies a probabilistic power flow (PLF) method to evaluate the influence of distributed generation with PVS. Firstly, the probabilistic...
This paper uses concepts of eigenvalue structure analysis, and defines disturbance variables sensitivity and load sensitivity of PQ bus to determine voltage weak point and find the reason of voltage collapse. It provides numerical method of calculating disturbance variables sensitivity and load sensitivity of PQ bus, and verifies the numerical method with WSCC 9-bus system.
In existing load flow model of induction generators, the magnetizing path is moved to the stator terminal, parallel to the shunt capacitor, yielding the same stator and rotor currents. The power output is equal to the mechanical power input. The stator resistance and the machine loss are ignored. It can not provide the initial condition for the dynamic and control schemes requiring the exact stator...
This paper presents an on-line equivalent algorithm for power system based on phasor measurement unit. The method considers the changes of the system parameters and load level, which overcome parameters rift problem and the shortage of traditional two points power flow method that supposing the parameters are fixed after a small disturbance. On this basis, voltage stability and Alert margin are proposed,...
In this paper, an algorithm for diagnosis of voltage collapse point is proposed. The algorithm is based on load characteristics, voltage and current measurements. When all loads at a bus are voltage independent type, the voltage collapse point coincides with Maximum Loading Point. In maximum loading point, with voltage and current changes, apparent power delivered to the bus does not increase. In...
A comprehensive optimal regulation model for distribution networks is presented, which utilizes the reactive power regulating means, sectionalizing and tie switchers to reduce active power losses. A loop-based coding scheme is proposed for reconfiguration description. The reactive tabu search algorithm is employed to get the optimal solution. The efficiency of the proposed method is identified by...
According to the problems of the present power flow tracing methods, this paper proposes the concept of power supply path of source and a new flow tracing method based on the circuit analysis of the power supply path under the constraints of all the basic electrical laws. This method makes the research on power flow tracing is not confined to only consider the numerical decomposition of power flow,...
Based on analysis of the case of the saddle-node bifurcation and the limit-induced bifurcation, a new method for identifying and calculation bifurcation points in steady-state voltage stability analysis is presented. By using continuation power flow based on piecewise linear load prediction curve, in which the load increasing directions are determined by load prediction curve, it go through the collapse...
As power system interconnections become more prevalent, there has been an increase in use of thyristor controlled shunt connected compensation devices for dynamic power compensation and enhancement of real power transmission capacity. In this paper, an enhancement technique of real power transfer capacity of transmission lines is presented. A static var compensator (SVC) is designed and applied to...
A precise components modeling has a great influence on the power flow calculation. On the basis of the comparison with other algorithms, the backward-forward sweep power flow algorithm is chosen for the power flow calculation of the shipboard power system in the paper. Going with this algorithm, the six detailed component models are introduced, especially three phase transformer models are placed...
New energy powers such as wind power and solar power technology taken into the power system increase random fluctuation in the system, and therefore threshold-crossing problem of nodal voltage and load flow are becoming increasingly more significant. Based on semi-invariant and Gram-Charlier series, the paper considers the randomness of the generator and load, nodes relevance, random slip of branches...
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 constantly improvement of communication help the technology of WEB services find its way to the power dispatching system. Gived WEB services is actively populized and applied in this field, it is necessary to develop a series of application sofewares for power system analysis based on WEB platform. Static security analysis plays an important role in power grid's security analysis. However, with...
Power flow calculation is an important constituent in power system analysis, it is very necessary to modify the Newton-Raphson power flow Method that can accurately describe the characteristics of wind power in order to obtain accurate calculation results. This paper expands Newton-Raphson power flow method with the wind power, the asynchronous generator and doubly-fed induction generator are discussed...
Cost minimization is one of the main goals in electric market so economic dispatch and load allocating, named as optimal power flow (OPF), are more interesting concerns. In this paper a Modified Genetic Algorithm (MGA) is presented for the solution of the OPF. The control variables are unit active power outputs, generator-bus voltages and discrete transformer-tap settings. To overcome the operating...
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...
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...
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