Zhou Xiaoxin

Power System Analysis Software Package (PSASP)-an integrated power system analysis tool

In this paper, an integrated power system analysis tool called Power System Analysis Software Package (PSASP) is presented. A brief description of every constituent module of PSASP is given first, then user-defined (UD) modeling function and user program interface (UPI) are introduced further. Finally, the new development of PSASP, power system analysis software platform, is illustrated through a diagram.

Dynamic Modeling and Transient Simulation for VSC based HVDC in Multi-Machine System

Voltage source converter (VSC) based high voltage direct current (HVDC) technology, abbreviated as VSC-HVDC, is a new and attractive transmission technology. With switch device having turn-on and turn-off capability, such as IGBT, VSC-HVDC has special characteristics comparing to conventional HVDC. Some of these characteristics are: passive ac load can be supplied; active and reactive power can be controlled separately and simultaneously; no requirement for fast communication between VSC stations. Based on the method of current injection at the ac bus of voltage source converter, the detailed dynamic model for VSC- HVCD is developed. This model includes three parts, i.e. the quasi-steady model for the ac side of voltage source converter, the dynamic model for VSC-HVDC inner dc system and the model for VSC-HVDC control system. With the help of User Program Interface function provided by Power System Analysis Software Package (PSASP/UPI), the transient simulation algorithm for VSC-HVDC is designed. Simulation results for multi-machine system with VSC-HVDC has verified the developed VSC-HVDC dynamic model and the designed transient simulation algorithm. Simulation results also show that with the active and reactive power control capability, not only the steady-state power flow can be controlled, but the system damping characteristic of low-frequency oscillation can be improved.

Realization of Electromechanical Transient and Electromagnetic Transient Real Time Hybrid Simulation in Power System

This paper presents a new interface approach in electromechanical transient and electromagnetic transient real time hybrid simulation in power system. The approach includes a parallel interface time sequence adaptable for real time hybrid simulation and an interface circuit adaptable for the parallel interface sequence. It also presents a new method to solve matrix asymmetry problem in electromagnetic transient simulation part caused by the connection of electromechanical network in hybrid simulation. Two cases are studied, modified IEEE 14 nodes system, and Dongbei-Huabei-Huazhong-Chuanyu interconnection system, an actual China power grid. The simulation results show that the hybrid simulation interface approach presented in the paper is valid and effective, and real time hybrid simulation for a 5000 nodes level electromechanical transient network and an electromagnetic transient network including 5 generators and more than 20 transmission lines is realized

A New Algorithm for Distributed Power System State Estimation Based on PMUs

In order to implement a functional control scheme for a system, the current state of the system must be known. Otherwise, even the most complicated control system will be handicapped. State estimate is a well-known function in transmission network analysis. In this paper, based on the placement of phasor measurement units (PMUs), a new algorithm for distributed power system state estimation is presented. In the first part of this algorithm, with the placement of PMUs based on the improved method of bordered block diagonal form (BBDF), the large system can be divided into many small systems. In the second part, Using the data of PMUs between subsystems as boundary condition, the problem of distributed power system state estimation with weighted least square turns to the optimization problem with equality constraint. At last, the effectiveness of the proposed algorithm is verified with numerical simulation on 6-machine 25-bus power system, and the computational speed is fast and the result is accurate.

Parallel algorithms for transient stability simulation on PC cluster

Parallel processing is a promising technology to obtain on-line dynamic security assessment and real time simulation of power system. Many kinds of parallel computers have been used to implement the present algorithms. With the advantages of low cost, upgradability and scalability, PC cluster is attracting more and more attentions for parallel processing. In this paper, several parallel algorithms for transient stability simulation are discussed. The advantages and disadvantages of these algorithms on a PC cluster are of special concern. The parallel processing technologies discussed in the paper include network partition, linear equation solution, Newton type algorithms and some parallel-in-time algorithms.

Probabilistic Power Flow Calculation Using Sigma-Point Transform Algorithm

This paper introduces sigma-point transform algorithm for the probabilistic power flow problem. It is assumed that the uncertainties of bus power injections and network parameters can be estimated or measured. Using the sigma-point transform algorithm can accurately estimate the corresponding uncertainty in the power flow solution. Through series expansion of the traditional non-linear power flow equations, formulae of the true mean and covariance of the stochastic variable resulting from the non-linear transformation are obtained. In this paper it is proved that the transform method can approximate the true mean and covariance better than the linearization method does. Performance of the sigma-point transform algorithm agrees very close with the MCS results using IEEE 14 bus test systems.

Parameter determination of supplementary subsynchronous damping controller with residue method

This paper adopts residue method to determine the parameters of supplementary subsynchronous damping controller (SSDC) installed in static VAr compensator (SVC). In order to apply residue method, the author deduces a continuous model of SVC adaptable for subsynchronous resonance (SSR) study based on a dynamic phasor method. An example system with SVC based on the IEEE first benchmark model is analyzed. Parameters of SSDC are determined according to the residue associated with the critical torsional mode in the system. Eigenvalue results show that SSDC with parameters set so, can mitigate the occurrence of SSR.

Analysis of the Yimin-Fengtun 500KV TCSC on the Northeast China Power System

Abstract A TCSC (Thyristor Controlled Series Compensation) is proposed to be installed in the Yimin-Fengtun 500kV system at the Fengtun site on the Northeast China power system which will be the first 500kV series compensation of China. In this paper, amount of simulations are made to acquire characteristics of steady state and transient state of studied system. A comparison of system feature with the TCSC and fixed compensation is also given. An important point in the paper is about control strategy of the TCSC and influence of characteristics and parameters of the TCSC equipment on power system. It can be indicated that the TCSC can greatly improve the performance of power system and characteristics of the TCSC equipment must be deeply studied so as to be fully used to acquire more benefit.

Adaptive tracking algorithm for magnetically controlled shunt reactor control

This paper proposed an adaptive tracking algorithm for dynamic time-varying control of extra and ultra high voltage magnetically controlled shunt reactor (MCSR), based on the extensional model and linear regression algorithm, the output of controlled system will track the control objective, then both of the optimal static and dynamic characteristics can be got. The structure principle of MCSR magnetic circuit was analyzed, the linear regression equation in dynamic time-varying parameters was created according to the theory of dynamic parameter tracking, considering the relevance of power system and MCSR, least squares theory was used to construct the parameters tracking formula, the gain-adjustment adaptive system was formed accordingly, In the processing of data collection, the memory limit principle was used to avoid data saturation, stressing the innovation amendment to the model parameters. The controller can meet the demands of tracking the expected order, fast rapidity of initial convergence and high accuracy of convergence. Computer simulation results used in practical operation parameters confirmed the effectiveness and validity of control algorithm. The electromagnetic transient modular of PSASP has contained the controller model by program, it has the advantages of novel, practical, accuracy, fast-tracking and reliable, which provides the necessary implement for voltage control of extra and ultra high voltage magnetically controlled shunt reactor, also opens a new way to conduct the study of controller design for nonlinear element in power system.

Design and simulation on TCSC analog model and controller

This paper presents the design and simulation test results of an analog TCSC simulator. The TCSC analog model is designed with active compensation in order to minimize the voltage drop on the thyristor when switched on. A detailed description is given about the hierarchical structure and modular hardware of the TCSC controller. The analog experimental results from TNA study show that the TCSC controller is able to implement impedance control, as well as smooth transitions between inductive and capacitive reactance modes. The inner-loop control can damp the oscillations in the LC loop of TCSC therefore it is of benefit for transition from one TCSC operation mode to another. The response speed can be increased if desired. Based on the field conditions, the design and completion is useful to industrial implementation.