Han Yingduo

STATCOM modeling and analysis in damping power system oscillations

In this paper, we discuss the single-machine infinite-bus system with one static synchronous compensator (STATCOM) asymmetrically installed as a current source. Together with a classical two order generator model, a simple power equation is drawn to give direct and clear physical concepts on synchronizing and damping torque coefficients. On the basis of the equations, some basic issues, such as the relationship of voltage gain control and damping control, operating conditions and installation of STATCOM, are investigated by detailed theoretical analysis. Then with proportional controller for voltage and damping control, the digital simulation proves the necessity of multi-objective control of STATCOM in damping power system oscillations and supplying fast voltage support. Finally, nonlinear simulation demonstrates how STATCOM improves the power transfer ability of the system after a severe fault.

Operation and control of ASVG under system asymmetric conditions

In this paper, an approach controlling the trigger pulses of GTOs of ASVG to suppress the negative sequence current through ASVG caused by system negative sequence voltage is presented. The control law makes ASVG generating a negative sequence component voltage. Thus, negative sequence currents will not flow through ASVG and GTOs. Simulation and open loop experiment results show that the analysis and approach are correct and practicable.

The operation monitoring and fault diagnosis system for a /spl plusmn/20 Mvar STATCOM installation

The operation monitoring and fault diagnosis system (OMFDS) for a /spl plusmn/20 Mvar STATCOM installation is thoroughly discussed in this paper. Several reasons necessitate developing such a system. After investigating the unique position of the OMFDS presented in the whole installation, the paper studies its hardware and software architecture and various functions. Practical tests verify the validity of the OMFDS and its effect to improve the performance of the STATCOM installation.

Simultaneously-tuned decentralized control of excitation and STATCOM for voltage regulation and stability enhancement in power systems

This paper investigates the coordinated design of generator excitation and STATCOM controllers to achieve an effective trade-off between voltage regulation and system stability improvement in a single-machine-infinite-bus power system with STATCOM connected at the electrical mid point. Firstly, the authors derived the uniform system model, in which generators double-axis dynamics is considered and the voltage-sourced STATCOM is modeled as a one-order low-pass filter. By introducing a linear quadratic performance index, the control designing procedure can then be formulated into an optimization problem. A direct iterative algorithm is proposed next to simultaneously tune the decentralized feedback gains. Finally, digital simulations are fulfilled to verify the effectiveness of the proposed control strategy. Result shows that the power system with the coordinated controllers can obtain good voltage regulation performance as well as satisfactory stability improvement. Furthermore, the resulting controllers are based on local available measurements, which makes it feasible in practical applications.

The asymmetric control strategy of ASVG

The ASVG (advanced static VAr generator) system with high power thyristor GTOs, is an important device in a FACTS (flexible AC transmission system). The research into asymmetric control of an ASVG takes an important role in reforming of the power net and improving its technology in the 21/sup st/ century. The paper presents a control strategy which is based on fuzzy-self-study control theory, which accomplishes the corresponding control with a multi-object in a nonlinear ASVG system.

80C196MC microcontroller-based inverter motor control and IR2130 six-output IGBT driver

This paper describes how to apply the IR2130 to an inverter motor control and presents an overview of an 8xC196MC controller-based IGBT inverter motor control design. The IR2130 six-channel gate drivers perform all the requirements for interfacing logic level control circuits to high power IGBT devices.

Advanced modeling and control package for power system problems

An intelligent computer aided engineering (CAE) control design software and hardware package for power system control has been developed in this project. This package encompasses advanced control technologies, software technologies and hardware technologies. It allows the whole design process to be cycled easily and efficiently, thus considerably speeding up the control system design and prototyping. The main objectives of the project consist of: (l) modeling of STATCOM (static compensator) in power system; (2) development of computer aided engineering platform; (3) design and development of digital signal processor (DSP) based controller; and (4) development and application of advanced control techniques for STATCOM. Three types of controller, namely PI-auto-tuning, fuzzy logic control (FLC) and iterative learning control (ILC) are incorporated in the platform. For the real-time control, a DSP-based hardware controller is designed and implemented. Field-site experiments were carried out on a 10 kVAr STATCOM to show the performance of the controller and results are satisfactory.

Coordinative control of excitation and fast valving using artificial neural networks

A cooperative control scheme of power system generation excitation and fast valving based on artificial neural networks is proposed in this paper. Two neural networks are used to coordinate excitation and fast valving control. Digital simulation and physical laboratory experiments of a simple neural network controller are presented.<<ETX>>

Expectative modeling of wide-area damping networked control systems with long stochastic time delay

In this paper, the impact of stochastic time delay on wide-area damping networked control systems is analyzed. A disintegrate method of time-delay upon sampling period is approved. Furthermore, the expectative model of networked control systems with long and stochastic time delay, whose variance extent is larger than one sampling period, is theoretically proved and calculated. Finally, the effectiveness of this expectative model is confirmed on the simulation of a power system with 8 generators and 36 nodes.

The study of injecting voltage calculation in three-phase series power quality controller

The three-phase series power quality controller (SPQC) is a type of device designed for mitigating power disturbances. It compensates load voltage by injecting the missing voltage of the system into the line. In this paper, a novel method of calculating the injecting voltage in a three-phase SPQC is proposed. The voltage limit existing in series devices are discussed based on the phasor diagram of unbalanced voltage sags in the three-phase system. Two types of transform are put forward to increase the voltage limit of series devices. The control strategies of a 3-phase 3-wired SPQC concerning about the voltage limit are also put forward by using the transform. The control methods can both increase the compensate limit and mitigate voltage harmonics under serious unbalanced voltage conditions. Simulation and experimental results are presented to confirm that the new control method has better performance than those traditional methods especially under unknown unbalanced voltage disturbances.