THE DECENTRALIZED LOAD FREGUENCY CONTROL FOR MULTI-AREA POWER SYSTEMS

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.     

THE DECOUPLJNG CALCULATION OF MULTI-AREA POWER SYSTEM LOAD FREQUENCY CONTROL

The calculating burden of the decoupling judgement of multi-area power system load frequeney centrel is very large by tranditional methods. This paper changcs the decoupling judgement problem into a minimum cost network flow problem. The solution algorithm is out-of-kilter . algorithm which is characterized by simple manipaultion, fast and reliable convergence. In the paper, we discuss and calculate the decoupling problem of two arca power system load frequency control. The results show that the proposed approach is feasible and effective.     

Distributed Power Flow Method Based on Ward Equivalent

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.     

DIGITAL POWER SYSTEM STABILIZER ( DPSS )

A digital power system stabilizer ( DPSS ) and its design method are presented in this paper. The mathematical model of a single machine infinite bus power system is obtained using off-line parameter identifications, and on the base of the identified model the control system is synthesized by generalized minimum variance control principles. Through feedback combination of several signals this control system has double functions of damping low frequency oscillation and automatic voltage regulating. In order to avoid static errors the very effective way is to combine discrete generalized minimum variance control with continuous integral control. Besides the proposed control strategy is very simple in structures and very easy to realize. Simulation results under several cases have shown the correctness and effectiveness of the proposed control strategy.     

AN AUTOMATIC VOLTAGE REGULATOR USING IDENTIFIED MODELS

This paper obtains the mathematical model of a single machine infinite bus power system using the idea of parameter identifications. Because the noise is considered in parameter identification process, the model reflects the real system more exactly. On the base of the identified model this paper also presents a discrete automatic voltage regulator by minimum variance control principles. In order to avoid the static error, we combine discrete minimum variance control with continuous integral control and get very satisfactory effects. This proposed control strategy is very easy to realize. The simulation results show that in every case the dynamic qualities of the proposed control strategy are incomparably superior to that of the conventional PI regulator, which means the proposed control strategy has great practical values.     

Hybrid Intelligent Method for Dynamic Reactive Power Optimization

In dynamic reactive power optimization problem(DRPO), action number constraints of discrete variables should be considered.By integrating immune genetic algorithm(IGA) and nonlinear interior point method(NIPM), a hybrid method for DRPO is proposed.First,the original DRPO problem is converted to a continuous optimization problem by relaxing the discrete variables,and the solution is obtained by NIPM.Then,according to the feature of control variables,the original DRPO problem is decomposed into a continuous optimization sub-problem and a discrete optimization sub-problem.The discrete optimization sub-problem is solved by IGA,and the continuous one is solved by NIPM.By solving the two sub-problems alternately,the optimal solution of the DRPO can be obtained.The proposed hybrid method combines advantages of IGA and NIPM,and finds the approximate optimal solution of DRPO.Numerical simulations on the IEEE 14 bus system illustrate that the proposed hybrid method is effective.     

Fuzzy PID Power Adjustment of Computer Monitor and Control System for Hydropower Station

The computer monitor and control system for hydropower station is always a structure system of laminate distribution and open style. The system can adjudge active power and inactive power of water turbine according to the requirement. The operators in active-control level give the value of active power and inactive power for water turbine by computer workstation. PLC of LCU run the power control procedure by net communication in order to realize power adjust. The power adjust of water turbine mainly by speed control system and magnetization system. The 2-D Fuzzy PID Control Model is proposed in order to carry out power adjust of water turbine . In this new method the parameter of PID can self-neaten on line according to power deviation and power deviation rate. By means of this procedure the machine unit can obtain given power value rapidly, exactly and stably. It can make the power adjust of monitor and control system obtain good control characteristic and robust, and it is benefit to extend the work life of machine unit.     

Overall control strategy and operational performances of a doubly fed wind turbine generator system

In order to comprehensively and correctly analyze the real-time operational characteristics of a grid-connected wind turbine generator system, it is necessary to analyze the overall control strategies and operation performances of the wind turbine generator system. According to the type of a doubly fed wind turbine generator system, the mathematical models of wind turbine, drive train and doubly fed induction generator (DFIG) are presented. From the viewpoints of the maximum wind energy capture and safe operation of the wind turbine, a maximum power output control strategy is proposed by considering the DFIG loss minimization, and a variable pitch control strategy is also presented by considering generator rotational speed restriction and the output power restriction. Combined with a power decoupling strategy of DFIG, the overall operational performances of the doubly fed wind turbine generator system are simulated. By comparing the simulation, theoretical analysis and actual operational data, the results show that the presented model and overall control strategies of the doubly fed wind turbine generator system are valid.     

Predictive Control Approach for Active Power Filter Based on Neural Networks

In this paper, a predictive control approach using neural networks for active power filter is proposed. The control system of active power filter using this method make using of the internal model control technology based on neural networks, meanwhile, to solve its questions such as lag because of calculating using neural networks, a predictive model based on neural networks is introduced. Simulation analysis shows that this control approach can compensate the lag of system and take advantage of self-adaptive characteristic of neural networks. Good result can be obtained.     

A HIERARCHICAL CONTROL METHOD FOR REACTIVE POWER OPTIMIZATION IN LARGE-SCALED INTERCONNECTED POWER SYSTEMS

This paper presents a new hierarchical and coordinative control method for reactive power optimization in large-scale interconnected power systems. It combines the interconnection forecast method for hierarchical control in large-scale steady state industrial systems with the incremental linear programming method for reactive power optimization in real time. The results of applying the method to power system examples show that the method not only solves the problem of high dimension in order, but also keeps the advantages of the incremental linear programming method. The proposed method is also suitable for the security analysis of reactive power correction in large-scale interconnected power systems.     

A SENSITIVITY METHOD FOR THE WEIGHTING MATRIX SELECTION OF LINEAR OPTIMAL CONTROL

The paper analyses the relations between closed-loop system dynamic qualities and linear optimal control weighting matrix Q and offers a sensitivity method for selecting weighting matrix Q. As a practical example, a linear optimal supplement excitation control system is designed for a single machine-infinite bus power system using the presented method. Theoretical . analysis and simulation results have shown that the dynamic qulities of the control system are very satisfactory.     

OPTIMAL CONTROL OF REACTIVE POWER AND VOLTAGE BY FICTITIOUS VARIABLES METHOD

A method introducing fictious variables for resolving the linear model of reactive power and voltages control in power systems is presented. The method theoritically guarantees the resolvability and optimizition of linear programming model. This method has been proved successful by IEEE 6 -node test system and the several practical power systems such as 49-node, 155 -node systems.     

Network Partitioning Based on Threshold Search and Dynamic Scatter for Voltage/Var Control

Secondary Voltage Control is a new way of voltage control,firstly the power system is divided into many control areas whose electric distance is remote.The partitioning method of secondary voltage control is studied and an algorithm that combination of the threshold search and dynamic scatter is presented.That is,the initial grouping scheme is obtained by searching the threshold value.The dynamic scatter method then is used to regulate and improve the initial results.The method is based on system's physical character,it's unnecessary to modify the network's model and analysis the eigenvalue,so the compute rate is fast.Through comparing the method and the traditional methods,this method is proved to be a reasonable and feasible partitioning scheme.     

Development of Movement Control System of Shoe Leather Lumen CT Instrument

A method of solving the problem of shoe leather lumen measurement in shoe CAD/CAM by industrial CT technology is introduced,X ray industrial CT technology is studied. The paper gives a rational scheme of system dispose. This scheme can be not only meet the need of shoe leather lumen measurement, but also achieve ordinary measurement. An uncomplicated and practicable movement control system are proposed also. This scheme achieves high precision of movement position without expensive direct current servo-control. A new simple method measurement is developed and accurate control of position in movement of detector data insert is achieved. The image resolving power can meet shoe leather lumen measurement.     

Open motion control architecture of wind turbineand main controller design

In this paper, we propose a method to solve the problems with stochastic nonlinear and point to point architecture of the wind turbines. The proposed method presents an open motion control architecture and a linearized torque control system based on power curve LUT. We reference the PLCopen motion control standard that is used to design the linearized torque and pitch systems of the wind turbines. This proposes a new methodology for the main controller design and the system integration of wind turbines.     

Analysis on starting characteristic of continuously variable transmission system with reflux power

Considering on the characteristics of the transmission system and some key units of continuously variable transmission system with reflux power, a dynamic simulation model and a control strategy are established. The design method of the new continuously variable transmission system is verified by simulation. The simulation result on this continuously variable transmission system shows that the rotating speed of the driven plate can rise up rapidly during starting clutch engagement, and the sliding friction power is lower than 3 kJ which is nearly equal to one third of the friction power of the traditional vehicle.     

Fuzzy Control and Simulation of Regulating System for Permanent Magnet Synchronous Motor

This paper researches the fuzzy control and simulation of regulating system for PMSM in electrical vehicle. The mathematics model is set up.The PMSM,the PMSM measures demux, dq to abc converter and the three phrase PWM converter models are set up in MATLAB/ Simulink. The fuzzy controller is designed with two dimension fuzzy design method, and take E and EC as input variable, U is the output variable. According to the controller and models, the fuzzy control model of regulating system for PMSM is created in matlab/simulink. At last, to test the accuracy of the control method with the simulation result.     

Voltage Stability Control of Local Power System

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.     

Rapid Prototype Control of Hydraulic Automatic Transmission System Based on dSPACE

dSPACE is a prototype development and real-time control testing platform which is based on MATLAB/Simulink software. By establishing mathematic model of hydraulic automatic transmission system, the shift rules are achieved. A testing platform for hydraulic automatic transmission system is developed whose control software is programmed by simulink and using the dSPACE as the centre controller. The experiment of electric throttle control and power performance matching control of hydraulic automatic transmission system is carried out. the result shows that well matching performance of hydraulic automatic transmission system can be realizedby using the control strategy proposed in this paper, it provides a fast and efficient approach for researching and developing the hydraulic automatic transmission system.     

Research on the improvement of the convergencespeed for CDMA system power control

Optimal power control with game-theory has been a hot research topic in code division multiple access (CDMA) system. However, the convergence speed of the power control algorithm based on traditional static game-theory is not fast enough and the power fluctuation is large during the iterative process. In order to solve this problem, dynamic game-theory is introduced into CDMA system power control algorithm. The simulation results show that the proposed algorithm, compared with the distributed power control algorithm based on the traditional static game theory, can improve the convergence speed obviously with the same power spending.