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The fog haze weather occurred frequently in our country, when HVDC transmission lines through the haze area, especially ion flow field, the effect is particularly prominent. So study of haze weather influence on ion flow field of HVDC transmission line has important engineering significance. Firstly, the paper studied the effect of different environmental temperature and humidity on the suspended...
This paper proposes a new way based on FPGA to realize decoupled double synchronous reference frame software phase locked loop (DDSRF-SPLL) under unbalanced conditions. DDSRF-SPLL can lock in unbalanced grid voltage accurately as well as overcome the impact of the phase-locked loop on frequency performance in adopting the positive and negative sequence decoupling algorithm. When the frequency of three-phase...
A new modulation method is proposed to solve the unbalancing problem of neutral-point potential in the DC side in three-level (3L) three-phase neutral-point-clamped (NPC) voltage source inverters. Based on properties of current balancing of three phases and redundant short vectors, different short vectors have different time distribution factors, which can be used to improve the control of the neutral-point...
Based on the nonlinear dynamic modeling of photovoltaic power generation system output time sequences, parsing the kinetic characteristics of the output power of photovoltaic power generation system, the chaos characteristics of the photovoltaic power generation system output power is put forward. According to the phase space reconstruction theory, adding weight first order local prediction method...
In order to solve the larger harmonic measurement errors of capacitor voltage transformer (CVT), this paper puts forward a new method of Y-Δ equivalent conversion and cascaded transfer function combining with Bode diagram to study the transmission characteristics of harmonic component for CVT. Simulation work based on MATLAB of the influence of the key circuit parameters on the harmonic transmission...
It is a main issue to find valuable information from the power quality data because of its big volume, heterogeneity and low value density in the power quality monitoring system of the grid. An analysis system of the power quality analysis based on the data mining technologies is presented in this paper, consisting of the technologies of data cleaning, data fusion, cluster analysis, correlation analysis,...
Commutation failure is a common and highlighting fault in HVDC transmission system. According to the physical mechanism of thyristor turn-off process and carrier motion process, topology optimization method of HVDC converter valve is proposed for reducing the occurrence rate of commutation failure. The thyristors turn-off process is also simulated by Matlab/Simulink software. Simulation results verified...
Single line diagram of distribution network in power system played a key role to the daily maintenance, it has long been relying on manual drawing, but with the increase in the number of equipment in distribution network, artificial drawing difficulty increases gradually, and artificial drawing errors have been more, for the production and maintenance of distribution network has also had a negative...
This paper investigates biases of a parametric estimator of Doppler shift in mobile communications, and the result indicates that the conventional iterative autocorrelation function (ACF) estimator yields a significant estimation error at high mobile speeds. Therefore, a simple linear fitting is proposed to refine the Doppler shift estimation, in which only one fitting expression is required for different...
A method for distributed information processing in grid sensor networks using the roesser model and Fornasini-Marchesini (FM) space model has been proposed in the literature [1], [2]. The method can be used to implement linear systems in grid sensor networks. It can be shown, the wireless sensor networks (WSN) have to satisfy particular condition that is the sensors should be in grid. This limits...
This paper presents an On-Off Keying (OOK) receiver with sensitivity improvement approach. The RF frontend amplifier of the receiver is only a single-stage amplifier with front-end band-pass resonant network which can achieve gain around 30dB at 13.56MHz. The baseband amplifier is composed of two parallel amplification paths and the amplified signals from each path are combined at output node. This...
In this paper, we consider a transmit precoder design for multiple-input-multiple-output (MIMO) decode-and-forward (DF) half-duplex two-hop relaying system consisting of one transmitter, one relay, one information-decoding (ID) receiver, and one energy harvesting (EH) receiver, where all nodes are equipped with more than one antenna. Our objective is to maximize data rates of this system by designing...
A set of measurement system for the testing of transmission lines, composing of wireless center station, wireless current acquisition and transmission nodes, wireless voltage acquisition and transmission node, was designed, which was based on wireless communication. The high speed wireless bridge working at 2.4GHz together with the clock synchronization module based on the IEEE1588 communicating protocol...
Reliability of a navigation system is one of greatimportance for navigation purposes. Therefore, anintegrity monitoring system is an inseparable part of aviation navigation system. Failures or faults due to malfunctions in the systems should be detected and repaired to keep the integrity of the system intact. In this paper, we present a method based on wavelet analysis for detecting failures. The...
The paper investigates the mobile real time measuring station incorporating renewable energies to monitor the surface water quality. This type of measuring stations are designed to establish the Water Framework Directive (WFD) perceived by European Commission. The core goal in the discussed work is to attain self-reliance by the mobile monitoring station, by maximizing the use of renewable source...
In this paper, a new coordination photovoltaic/battery micro-grid control strategy is proposed to improve the micro-grid fault ride-through capability. Under normal condition, the proposed strategy can restrain the influence of load fluctuations. When symmetrical grid fault happens, the micro-grid can ride through it by the proposed strategy. The DC-link bus voltage and AC current could be kept stable...
In a DC microgrid (MG) with droop control system only, there exists an inherent deviation between DC bus voltage and its rated value during the steady-state operations. In order to eliminate the inherent deviation, a secondary voltage regulation system (SVRS) based on vanadium redox battery (VRB) storages is proposed in this paper. It adopts double closed loop control strategy coordinating with the...
This paper summarizes current research and applications of wind turbine individual pitch control, reviews the basic concepts and working principles of individual pitch control methods, analyses the individual pitch control strategies for reducing the load, and mitigating grid voltage fluctuations, finally, the possible development prospects of wind turbine individual pitch control are discussed.
This paper proposes a concept of free piston linear generator (FPLG) range-extender for the application of hybrid electric vehicles (HEVs). The coupling thermodynamics model of the FPLG range-extender is developed mathematically. Its stable operation characteristics are analyzed accordingly. In addition, the effects of the variations of the key operational parameters on the effective output power...
Temperature of windings increases because of the heat generated during motor running process, therefore motor parameters will be changed. The effects of temperature on external characteristics of the motor were analyzed as the rising temperature causes demagnetization of the permanent magnet. A new control strategy is designed to reduce the influence of the temperature. The simulation results show...
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