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1.
In this paper,the conception of bus voltage stability control area of local powersystem is presented,based on the practical criterion for voltage stability calculated by the real-timeinformation and the quasi-real time information form the power system.The method is test6d onIEEE-30-bus test system and results are satisfactory. 相似文献
2.
The voltage instability of power system often occurs when the active power on one or more weak branches exceeds its transfer capability. A preventive control model for static voltage stability is proposed using the active power transfer capability of weak branches as static voltage stability constraints. A local line based voltage stability index is used to determine the critical contingencies, weak branches and transfer capability of each weak branch. A static security analysis method, which is based on DC power flow equations, is used to establish the non linear active power flow expressions on weak branches following each critical contingency. The active power constraints on weak branches can be obtained from the active power flow expressions and transfer capabilities of weak branches. A quadratic optimal model for preventive control including the proposed active power constraints on weak branches is presented. The simulation results for IEEEE14 bus system and IEEE118 bus system demonstrate the correctness and effectiveness of the proposed preventive control model. 相似文献
3.
Based on the research of a practical project for high hrequency high voltage switching power supplies,the state space average model as well as the transfer function of single end flyback converters,which can be used to analyze the stability of single end flyback switching power supplies,are established. 相似文献
4.
With interconnecting and developing of power system, the problem of power flow computation on dispersed data resource need to be solved. A new distributed computation method of power flow based on Ward equivalent is presented. According to master-slaver splitting principle, multi-area interconnected power system is divided into master-slaver areas. Boundary buses in different areas are defined as different bus-types. Neighborhood areas are equivalent by Ward equivalent principle, and the equivalent injection power and equivalent impedance are worked out. Power flows from master area to slaver areas are solved by Newton method, and the equivalent injection power and equivalent impedance on the boundary are modified by their solutions. The process above repeats until to convergence. The proposed distributed power flow method takes full advantage of the information of power, voltage, network configuration in neighborhood areas, so it is better on convergence and quality of solution. The proposed algorithm is testified by IEEE 14-bus system and a practical 181-bus system. 相似文献
5.
Deng Renming Wang Daen Lin Ying 《保鲜与加工》1993,(3):36-41
The communication of the application program among work tations of 3+ network is realized by the shared file on harddisk of the network server,which does not support the application program' s real-time communication among the network workstations nor supplies software or hardware needed for information refreshing, nor fits for field multibatch continuous real-time transmission and processing of working condition information, by using the NETBIOS function call method, the real-time communication among network workstations is realized and a power plant working information background real-time communication and data processing system is developed which effectively traces working condition from tow 200 MW power plant generators, altogether 321 points from a cycling detecting system and 78 binary points for broadcasting the information to other workstations,and realizes a complx display of 14 working condition graphs and a real-time data simulation graph. 相似文献
6.
ZHANG Si-jie ZHAO Xiao-yu ZENG Xiao-ping PENG Cheng-ling GUO Xing-ming SHI Ling 《保鲜与加工》2011,(5):130-134
To solve the problem of low control accuracy and low stability of current X-ray machines, a kind of digital power supply for X-ray machine is introduced. In the digital power supply, some key technologies are used to improve the output stability of the high frequency inverter, including improved BUCK circuit for voltage regulating circuit, high frequency inverter and soft switching technology for the high-voltage generator. The PWM control technology is used to control the switch transistor of voltage regulating circuit and inverter circuit, which makes the drive waveform output stable and easy to control. In order to improve the control accuracy, reduce the volume and change high voltage consecutively, the software PID of the microcomputer is used to control the feedback circuit. The high-accuracy power chip is used for the filament power supply to make the filament electric current stable. Through the analysis of the circuit, the parameters of the circuit are calculated and the circuit is simulated by PSPICE software. The results show that the theoretical analysis is consistent with the practical simulation results. The design can meet the requirement of the technology indices of the power supply of the X-ray machines. 相似文献
7.
Concept of stability is vague, but it is basic characteristic of dynamic system, and precondition that make all kinds of control system run normally. Today it is still a challenge to analyze stability for uncertainty complex control system, whose mathematic modeling is impossible or very difficult, so it is very hard to judge whether a system running is stable or not by mathematic stability criterion. A kind of analyzing method is presented, which combine absolute stability with self-locked concept of heuristic search, it may analyze system stability in more range through adjusting self-collected loop parameters for uncertain control system based on knowledge control model. It is shown that stability analyzing method is effective and suitable for practical physical system in the engineering project. 相似文献
8.
Based on the research of a practical project of high frequency high voltage switching power supplies,the system design and experimental investigation of a single end flyback high frequency high voltage switching power supply are presented. In order to solve the problem of durable voltage of power MOSFETs that are used in the single end flyback high voltage switching power supply,an effective approach that adopts dual MOSFETs in series connected is proposed.The procedure of the designing and the parameter of each device is given in detail.A prototype of 220 Volt input and 2000V/3mA output is developed, and the validity of the scheme is demonstrated by the experiment. 相似文献
9.
This paper proposes a control scheme for a doubly-fed induction generator (DFIG) wind farm with VSC-HVDC grid integration to ensure secure and reliable operation of power system with fluctuated wind power penetration. The whole system dynamic models are respectively described. Based on vector control system with a virtual voltage orientation, a steady-state voltage control block and a dynamic voltage control block with a cross-product term of d-q currents are separately designed for WFVSC to control the corresponding parts of the wind farm voltage. Meanwhile, with the consideration of AC and DC side parameter variation and external disturbance, an improved backstepping control scheme with Lyapunov stability provement is also proposed for the GSVSC. The combination of the two schemes makes up the new control design of this study. Besides, to verify the performance of the proposed new control design, three different cases are suggested which contain the AC and DC side parameter variation and external disturbance such as local load cut off-in, grid voltage harmonics. Finally, numerical simulations using MATLAB/Simulink are presented for a 200MW DFIG wind farm with VSC-HVDC grid integration to validate the proposed control scheme and demonstrate the improved system operation performance. Moreover, the corresponding discussions are also presented for further illustrations. 相似文献
10.
Gao Feng Qin Yihong 《保鲜与加工》1991,(5):36-41
A decoupled load-frequency control model of a multi-area interconnecting power system is presented and a practical and effective decentralized control method is developed, which needs only its own state information and the information measured in it. It can also improve the stability and dynamic characters of the system. The dynamic simulation of the numerical example of a three-area interconnecting system with this controller showes the dynamic characters are almost the same as the centralized full state feedback optimal control. 相似文献
11.
The power transmission line is one of the important parts of electrical power system,the management and inspection of the transmission lines have been significant routine job ensuring the reliability of the transmission system. This paper describes in detail the basic principle of the intellectual transmission line inspection system using Geographic Information System(GIS) and Global Position System(GPS) technology.This novel inspection system is composed of pocket PC,GPS receiver and management PC,and takes full advantage of modern computer and network communication technique.Owing to the advantages of high reliability,practicability and scalability,the practical application of this intellectual inspection system shows that it completely meets the requirements for fast speed,high efficiency and real-time performance. 相似文献
12.
基于LabVIEW的潜油电泵数据采集系统 总被引：1，自引：0，他引：1
应用LabVIEW虚拟仪器现场可编程门阵列(FPGA)对潜油电泵的电压、电流参量进行实时数据采集,通过上位机对采样数据进行分析处理,得到潜油电泵的视在功率、有功功率、无功功率和功率因数,并与电能质量检测仪检测数据进行对照。系统硬件采用NI sbRIO-9606和NI9683夹层板配合使用,突破了传统的依靠DAQ助手的硬件采集,基于现场可编程门阵列(FPGA)的数据采集系统,由软件构成采集功能芯片,可控性强,准确性高,应用性好。实验表明,该系统在误差允许范围内能够对数据进行准确采集。 相似文献
13.
Reliability Evaluation Model of Composite Generation and Transmission System Incorporating FACTS Devices 总被引：1，自引：0，他引：1
The utilization of Flexible AC Transimssion System(FACTS)technology has significant impact on power system reliability performance.Series FACTS devices such as Thyristor Controlled Phase Shifting Transformers(TCPSTs) and Thyristor Controlled Series Compensators(TCSCs) can change the natural allocation of the power flow and effectively alleviate transmission congestion.Parallel FACTS devices such as Static Var Compensators(SVCs)can provide reactive power support and maintain voltage stability.So it is important to quantitatively evaluate their benefits to the power system reliability.The traditional models of the composite generation and transmission system reliability evaluation are mainly focused on conventional generation and transmission facilities.This paper researches the power flow model of TCPST and TCSC,and then presents the optimal load shedding model incorporating TCPSTs,TCSCs and SVCs and effectively incorporates them into the reliability evaluation model.The proposed method is tested on the RBTS and the obtained results show that the system reliability can be improved effectually by FACTS devices. 相似文献
14.
Installing compensation equipments is a good manner to improve line transmission capacity and maintain power system stability in the extra high voltage(EHV) long distance transmission line.It is of benefit to analysis and control by describing the effect of compensation equipment correctly.At present,for predigesting analysis or increasing real-time calculating speed,concentrated parameter circuit model is widely used to analyze 500 kV EHV long distance transmission line which may cause bigger error.So it is necessary to get a more reasonable model.On the basic of voltage and current distributed equations of even distributed long distance line,this paper deduces phasor diagram and power-angle character equations of uncompensated long line.Then the authors analyze the effect of compensators and define two characteristic parameters,namely,equivalent impedance x_(eq) and voltage coefficient K_V.Any compensating states of EHV long distance transmission line,example installing the compensators in the line or not or which type of compensators,is described by the general phasor diagram and power-angle characteristic equations.Furthermore,increment calculation(equations) of two characteristic parameters is presented by the compensator parameters which may make the concepts clear and predigests analysis easily. 相似文献
15.
The purpose of a power system is to deliver the power the customers require in real time, on demand, within acceptable voltage and frequency limit, and in a reliable and economic manner. Using NLPNN (New Linear Programming Neural Network) model, the behavior analysis of power system under fault conditions is carried through. The stability and convergence theorems are set up to obtain the resolution for the problem of the load curtailment strategy. A new way is open up to evaluate the reliability of power systems and the great progress in calculation analysis model is achieved. The new calculation technique and theory foundation of reliability evaluation are supplied. 相似文献
16.
Zhao Youxin 《保鲜与加工》1988,(4)
A new approach based on sensitivity method for the optimal power flow is presented in the paper. This method has the following advantages: it is suitable to solve a 200-node power system on the microcomputer; the convergence is easy to reach and the computation speed is quick; it is possible to reduce 8-14% power loss and to get maximum economic benefit by using this method; in power system dispatch center it can be used as an on-line voltage and reactive power control program to keep good voltage level. The proposed method has been proved successful by IEEE 118-node test system and the several real power systems such as 49-node, 61-node, 99-node and 200-node systems. 相似文献
17.
Zhang Yongxing Li Bo Wang Guilin 《保鲜与加工》1999,(2):1-4
Based on the practical project a study on analysis methods for rock slope foundation stability of highrise-building project criterion transfer coefficient method, rotation limit equilibrium method (Sweden slices method) and finite element method was carried out.The authors found that safety factor of criterion transfer coefficient method is larger than that of rotation limit equilibrium method, but is similar to the results of finite element method. So, when rockslope foundation stability of highrise building is to be analysed,the rotation limit equilibrium method is suggested to use. 相似文献
18.
VHS-ADC high speed digital signal processing platform based on MATLAB and FPGA could be used to build three-phase voltage source rectifier with space voltage vector PWM(SVPWM).The initial phase of coordinate transformation from three phase static coordinate to two phase static coordinate which is called Park transformation and from two phase rotating reference frame to two phase static coordinate is uncertain. There existed noise in acquiring grid voltage and current. Digital phase-locked loop is added to follow the frequency and phase of grid voltage, FIR filter is added to process signal and reduce the interference. External voltage control loop, internal current control loop and the model of coordinate transformation are designed on the VHS-ADC platform. The small power experiment is conducted to verify the stability and feasibility of the control system. The experimental results show that the digital phase-locked loop and FIR digital filter can be applied to three-phase voltage source rectifier. 相似文献
19.
Current online auction modes are all non real-time and have many defects. They are centered on auctioneers, forming star shaped information communication mode among auctioneers and bidders, and are actually the computerization of traditional auction mode. The power of Internet has not been fully utilized. In order to solve these problems, a real-time online auction mode is put forward. In this mode, bidders and auctioneers have peer-to-peer status, forming netlike information communication mode between two sides. The characteristics of real-time online auction are analyzed. The application of Multicast technology in real-time online auction and how to lighten the burden of bidders and auctioneers by intelligent Agent technology are elaborated. Finally, the application effect of real-time online auction is verified through an experimental system. 相似文献