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A power conditioning system consisting of a Super-conducting Magnetic Energy Storage (SMES) which can be used to smooth out differences between output power of a generator and power loads is analyzed in this paper. The SMES is connected in shunt with the distribution lines through a converter. The converter is a voltage source converter type with a DC-chopper. The system is controlled by three regulators;...
Due to the increasing of power system fault and failure, voltage sag (dip) will occur instantaneously with respect to the fault and failure itself. The power system network consists of high voltage (HV), medium voltage (MV) and low voltage busbar (LV). Monitoring equipment in the power systems network are installed at strategic and appropriate 33/11 kV feeder. The propagation and the travelling of...
Protective relays, especially IDMT (Inverse Definite Minimum Time) overcurrent relays is crucial in the power system protection. It is important that in any case of the system abnormalities or faults, the IDMT overcurrent must be capable to isolate only the faulty component from the healthy system. This paper presents the study on the coordination of the IDMT relay in the tested network whereby the...
Four kinds of compound carrier disposition PWM schemes are discussed, two of which are proposed for the first time in the paper. Methods for analyzing the amplitudes and harmonics of the output voltage of single-phase multi-level cascaded inverter are introduced for these PWM schemes, whose carrier waves could be equivalent to the ones of phase-shifted-PWM. Features of these PWM schemes are summarized...
This paper proposes a new starting method of a harmonic current compensator using a hybrid active filter for wind power generation systems. In the proposed method, an active filter of the hybrid power filter behaves a resistor and reactive power compensator to suppress the inrush current and leading currents for the passive filter under the starting condition. The basic principle of the proposed starting...
In this paper is proposed an adaptive control method of the active power of a nonlinear load. One of the most representative nonlinear loads is the Electric Arc Furnace (EAF). Based on the experimental results will be proposed an adaptive control system of the process. The algorithm used is known as the LMS algorithm (Least Mean Square) being, due to its simplicity, the most used algorithm implemented...
This paper investigates a case study of grid integration of large offshore wind farm and oil & gas installations using Line-Commutated-Converter (LCC) HVDC transmission system. Additionally, a STATCOM provides commutation voltage and reactive power to the system. The Wind farm supplies power to oil & gas installations through the offshore AC network, and to the onshore grid through the LCC-HVDC...
The state space averaging method, switch cycle average method and switching function method for modeling of static var generator (SVG) main circuit are reviewed. The commonness among the three methods is found and the power model of SVG is carried out by the instantaneous reactive power theory and the main circuit model of SVG. Based this power model, the bivariate PI control strategy is introduced...
Wind energy is one of the most important renewable energy sources due to its unique characteristics such as cleanliness and availability. Since wind blow swings have major effects on voltage levels and active and reactive powers of wind turbine generators, it is of vital importance to fully analyze the power system containing such generators via transient simulation with distributed generation units...
Based on the IEEE9 buses system provided by the simulation software BPA, the electromagnetic transient model of the 9-bus system in PSCAD/EMTDC is modeled in this paper. The steady-state characteristics and dynamic characteristics of IEEE9 buses system in BPA and PSCAD/EMTDC are compared in this paper. Then, the differences of simulation results between the electromechanical transient model and the...
A novel method of intelligent automatic layout of one-line diagrams for district electrical distribution network is proposed in this paper. Initially, a set of aesthetic criteria ("distributing of substation diagrams evenly in the frame\minimum line\limited crossings") have been introduced. Further, a modified particle swarm optimization algorithm is presented to search the best layout of...
This paper presents a new voltage source inductive filtering converter (VSIFC) for HVDC-light transmission system, which is mainly composed of the inductive filtering (IF) transformer and the related full-tuned (FT) branches with the commutating function for the self-commutated converter. This paper concerns on the technical feasibility on the application of VSIFC in HVDC-Light systems. Firstly, two...
This paper presents some new technologies of modular multilevel converter (MMC) for VSC-HVDC application. The origin of modular multilevel VSC and its essential working mechanism are clarified in detail. Then, the starting of MMC under de-energized condition is discussed and a simple but effective control scheme is proposed. Concerning the drawbacks of traditional PWM modulation technologies, i.e...
The method of voltage sag source location proposed in this paper is using wavelet-multiresolution to decompose the voltage and current waveforms from monitoring points and analyzing the change of signal energy of three-phase instantaneous power during voltage sag to ascertain the sag source location relative to the monitoring points. The location of voltage sag caused by line fault, transformer energizing...
A novel main circuit topology of voltage quality disturbance generator is proposed in this paper, composed of PWM rectifier and cascade H bridge inverter. The three phase inverter is decoupling controlled. The main advantage of the topology is a hybrid structure, the mainly power of voltage quality disturbance generator is supplied by system source and the small power is supplied by inverter, so the...
For large scale AC/DC transmission schemes with multiple series capacitors compensations, how to assess the risk of subsynchronous resonance (SSR) rapidly is of great practical significance to ensure that the grid operates safely and stably. According to the practical project of meeting summer peaks in 2009 of China Southern Power Grid (CSG), this paper combines a static equivalence method, Modified...
The simulation model of synchronous generator has an important role in power system simulation. The correct values of parameters of the various generator models in different simulation tools are even more important. The methods of parameters transformation of synchronous generator model (with excitation system) in BPA and PSCAD are discussed in this paper. If the parameters of the same model are transferred...
This article reviews the design of algorithms for individual pitch control in the case of variable speed turbines. The aim of the designed control algorithm is to improve the power quality and to reduce voltage flicker. A simulation model of variable speed wind turbine was developed with the simulation tool of PSCAD/EMTDC. This article compared the individual pitch action and the collective pitch...
The stator flux-oriented vector control theory is adopted for megawatt double-fed induction generator (DFIG). Rotor excitation current is regulated according to grid voltage and rotor speed to realize no-load grid connection of DFIG. The control strategy is switched after grid connection successfully to realize maximum power point tracking (MPPT) and power decoupled control. The control of the rotor-side...
This paper presents an electromagnetic transient model including the east, central and southwest China 500 kV grid, UHVAC nationwide backbone network and 9 HVDC systems using PSCAD/EMTDC based on BPA Dynamic equivalent model data of the network around 2015 and Simulation is carried out to compare single model of BPA and PSCAD/EMTDC. HVDC and UHVDC transmission system models in BPA are analyzed and...
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