Wu Zhongxi

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.

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

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.

A Novel implementation of IEC 61970 CIS based on Ice middleware

Supporting IEC 61970 is one of the key features of new generation EMS (energy management system). IEC 61970 standard and its status quo is introduced briefly. The characteristics of CIS (component interface specification) and Ice (Internet communication engine) are researched. The realization of DAF (data access facility), which is a basic part of CIS is expounded. The test results about interface implementation show that it is not as efficiency as a certain CORBA (common object request broker architecture) implementation for some history reasons, but, compared with other middleware, Ice possesses superiorities of advanced technique and abundant functions and meets the requirements of distributed system establishment

A Practical Network Portioning Method for Parallel Processing of Power System Simulation

On the basis of contour tableau method, though the optimization of contour tableau constructing process, a power network portioning method for spatial parallel simulation is presented in this paper. On the basis of presented method, a task-partitioning module for parallel electromechanical transient simulation is developed. Using a practical power network, Northeast China, North China, Central China, Sichuan and Chongqing interconnected network, the presented network portioning method is compared with the original contour tableau method and path tree method. Comparing results show that, using presented method, the number of boundary nodes is reduced and higher parallel efficiency is achieved, while the size balance among subnets is kept

Research and practice of integration of information in power dispatch center

For different computer technology and development practice during periods, information systems are often isolated with each other in power dispatching center. Shares of information resource have been proved to be difficult and expensive. The two typical data resources, online EMS data and offline data are analyzed. The technology of integration of the two data sources is researched and developed. Integration of several online/offline data at one time is supported in the method. Normal variety of power grid data is adaptable. With simple manual maintenance, abundant output could be shown by graphics or data table visually. By applying in the state power dispatching center, it is verified that the technology of data integration is feasible and improves the accuracy of the input data for advanced applications, thus make the result more reasonable and reliable.

A novel approach to evaluating small-disturbance voltage stability of large scale AC/DC power systems

Considering generator dynamics, load dynamics and HVDC dynamics, the differential and algebraic equations for analyzing small-disturbance voltage stability of large scale AC/DC power systems are established and a new voltage stability criterion is presented based on some reasonable assumptions and rigorous mathematical derivation. The criterion is that the determinants of two different power flow Jacobian matrices should have the same signs. By using the criterion, the dynamic problem of power system small-disturbance voltage stability can be treated as a static problem, so the eigenvalue analysis is avoided and the computation burden is reduced. The calculation results on two sample systems show that the novel approach proposed in this paper is correct and feasible.

A Practical Method to Implement Hardware-In-Loop testing in Parallel Electromechanical Transient Digital Simulation

Real-time electromechanical transient digital simulator simulates the transient process of power system after fault or other disturbances, and provides an ideal platform for fault-analysis, model validation and physical device testing. Providing interface for physical device and realizing the tests of dynamic component and automatic control devices are important functions of power system simulator, which can be used in many fields. The physical device interface of digital simulator involves both hardware and software parts. A practical method is presented to implement the software parts of physical device interface. Based on the presented method, an interface between physical device and electromechanical simulator is implemented. Two test cases, CEPRI36 and Central China power system, are used for a PSS device test. The hardware-in-loop testing results are very close to those of digital model, which validate the rightness of presented method.

Voltage stability problems of Gansu Power Grid: assessment and countermeasures

Concerning voltage stability, sufficient attention was not necessarily paid in the past as it was done for rotor angle stability. Illustrated on Gansu Power Grid in Northwest China Power System, a systematic approach to voltage stability assessment is presented in this paper. First comprehensive static and dynamic analysis on the voltage stability problem of Gansu Power Grid are conducted, by which the process and the type of loss of voltage stability is clarified. Based on the analysis results, two economical remedial measures are proposed. The simulation results show that the proposed countermeasures are effective to improve the voltage stability margin of the system.

Small-signal stability analysis based on user-defined model

This paper introduces a comprehensive computer program for small-signal stability analysis of power systems, which is a part of the Power System Analysis Software Package (PSASP). Exploiting the user-defined modeling technique, the program can easily simulate almost any kind of dynamic unit models. With the sparsity-based eigenvalue algorithms used the program can be applied to large-scale power system. Two systems of different size and complexity are studied to evaluate the performance of the program.