基于Power World Simulator的地区电网静态安全稳定性分析

电力系统具有良好的稳定性是保证电网正常运行的关键,充分应用Power World Simulator电力系统仿真软件对我国西北某地区实际电网进行安全稳定性分析。根据给定的实际电网运行数据搭建电网模型并进行潮流计算,将潮流计算结果与静态安全理论相结合,对该地区电网模型进行N-1静态安全性分析。针对线路负载率过高以及节点母线电压越限的情况,提出解决措施以达到提高电网运行稳定性的目的。

Design and Simulation for the Pulse High-Voltage DC Power Supply (HVPS) of 1.2 MW/2.45 GHz HT-7U Lower Hybrid Current Drive System

The superconducting tokamak HT-7U [1] has been designed by the Institute of Plasma Physics since 1998 and will be set up before 2003. The 1.2 MW /2.45 GHz HT-7U LHCD (Lower hybrid current drive) system which being the most efficient non-induction device can heat the plasma and drive the plasma current has been efficiently in operation 'owl and a particular design of the 2.8 MW/-35 kV high-voltage DC power supply has been already completed and will apply to the klystron of LHCD on HT-7 and the future HT-7U, and the project of the power supply has been examined and approved professionally by an authorized group of high-level specialist in the institute of Plasma Physics. The detailed design of the power supply and the simulation results are referred in the paper.

Hybrid Simulation of ±500 kV HVDC Power Transmission Project Based on Advanced Digital Power System Simulator

In order to effectively imitate the dynamic operation characteristics of the HVDC （high voltage direct current） power transmission system at a real ±500kV HVDC transmission project, the electromechanical-electromagnetic transient hybrid simulation was carried out based on advanced digital power system simulator （ADPSS）. In the simulation analysis, the built hybrid model＇s dynamic response outputs under three different fault conditions are considered, and by comparing with the selected fault recording waveforms, the validities of the simulation waveforms are estimated qualitatively. It can be ascertained that the hybrid simulation model has the ability to describe the HVDC system＇s dynamic change trends well under some special fault conditions.

Full-digital real-time power system simulator conferred nation's top award

On January 11, 2010, the grand ceremony to present the 2009 National Scientific and Technological Award was held in Beijing. The project—Development and Implementation of Full-Digital Real-Time

Plasma Simulation of Dielectric-lined Multiwave Cerenkov Generators Producing High Power Millimeter Waves

This paper presents the concept of a Dielectric-lined Multiwave Cerenkov Generator producing high power millimeter waves, which has been investigated with a two and onehalf dimensional electromagnetic relativistic Particle-in-Cell (PIC) plasma simulation code. Themodified device can operate in a lower diode-voltage regime with much higher radiation efficiencyand slight downshift of operation frequency. There exist the optima for the permittivity of thedielectric liner and for the magnitude of the guiding magnetic field. The required intensity of theguiding field is reduced by the introduction of the liner. The enhanced propagation of the electronbeam is studied in the presence of the liner.

500 MW Unit Simulator for Panshan Thermal Power Plant Passed Acceptance

After a thorough demonstration in Panshan Thermal Power Plant, the 500 MW super critical pressure unit simulator developed by the Simulation & Control Institute under the North China University of Electric Power was accepted by experts from the North China Electric Power Group Company on 3rd August 1996.

An Adaptive Simulation Algorithm Based on Fuzzy Stiffness Recognition and Its Application to Power Station Simulation

The adaptive simulation algorithm (ASA) based on stiffness recognition is an effective and applicable simulation method. In this paper, a principle of the said method is briefly introduced and more importance is stressed in studying the value of its application by realizing it in MMS.

Modeling and Simulation of a Transmission Line Response to a 400 kV/400V Capacitor Coupled Substation

The access to electricity in rural areas is extremely limited, but it is crucial for all citizens. The population in rural areas of sub-Saharan African (SSA) countries is generally low, making it economically unfeasible to implement traditional rural electrification (CRE) projects due to the high cost of establishing the necessary distribution infrastructure. To address this cost issue, one alternative technology for rural electrification (URE) that can be explored is the Capacitor Coupled Substation (CCS) technology. CCS is a cost-effective solution for supplying electricity to rural areas. The research is necessitated by the need to offer a cost-effective technology for supplying electricity to sparsely populated communities. This paper examines the impact on the transmission network when a 400 kV/400V CCS is connected to it. The system response when a CCS is connected to the network was modeled using MATLAB/Si-mulink. The results, based on the fixed load of 80 kW, showed negligible interference on the transmission line voltage. However, there was minor impact on the parameters downstream of the tapping point. These findings were further supported by introducing a fault condition to the CCS, which showed that interferences with the CCS could affect the overall stability of the transmission network downstream of the tapping node, similar to the behavior of an unstable load.

Numerical simulation of the flow field of a flat torque converter

A flexible flat torque converter was proposed to fulfill the requirement of miniaturization and power density maximization for automobiles.Constructed by two arcs joined by lines,the torus was designed directly from design path.The influence of flatness on the performance of the torque converter was evaluated.The software CFX and standard k-ε model were adopted to simulate the internal flow fields of the torque converter under different flatness ratios.The results indicated that the performance of the torque converter got worse as the flatness declined,but the capacity of pump increased.The efficiency and the torque ratio dropped slightly as the flatness ratio decreased.So the torque converter could be squashed appropriately to get high power density without too much efficiency sacrifice.But when the flatness ratio was below 0.2,there was a significant drop in the efficiency.

Resource pre-allocation algorithms for low-energy task scheduling of cloud computing

In order to lower the power consumption and improve the coefficient of resource utilization of current cloud computing systems, this paper proposes two resource pre-allocation algorithms based on the ＂shut down the redundant, turn on the demanded＂ strategy here. Firstly, a green cloud computing model is presented, abstracting the task scheduling problem to the virtual machine deployment issue with the virtualization technology. Secondly, the future workloads of system need to be predicted： a cubic exponential smoothing algorithm based on the conservative control（CESCC） strategy is proposed, combining with the current state and resource distribution of system, in order to calculate the demand of resources for the next period of task requests. Then, a multi-objective constrained optimization model of power consumption and a low-energy resource allocation algorithm based on probabilistic matching（RA-PM） are proposed. In order to reduce the power consumption further, the resource allocation algorithm based on the improved simulated annealing（RA-ISA） is designed with the improved simulated annealing algorithm. Experimental results show that the prediction and conservative control strategy make resource pre-allocation catch up with demands, and improve the efficiency of real-time response and the stability of the system. Both RA-PM and RA-ISA can activate fewer hosts, achieve better load balance among the set of high applicable hosts, maximize the utilization of resources, and greatly reduce the power consumption of cloud computing systems.

Exploration of Artificial-intelligence Oriented Power System Dynamic Simulators

With the rapid development of artificial intelligence(AI),it is foreseeable that the accuracy and efficiency of dynamic analysis for future power system will be greatly improved by the integration of dynamic simulators and AI.To explore the interaction mechanism of power system dynamic simulations and AI,a general design for AI-oriented power system dynamic simulators is proposed,which consists of a high-performance simulator with neural network supportability and flexible external and internal application programming interfaces(APIs).With the support of APIs,simulation-assisted AI and AIassisted simulation form a comprehensive interaction mechanism between power system dynamic simulations and AI.A prototype of this design is implemented and made public based on a highly efficient electromechanical simulator.Tests of this prototype are carried out in four scenarios including sample generation,AI-based stability prediction,data-driven dynamic component modeling,and AI-aided stability control,which prove the validity,flexibility,and efficiency of the design and implementation for AI-oriented power system dynamic simulators.

Optimal allocation method of energy storage for integrated renewable generation plants based on power market simulation

This study designs and proposes a method for evaluating the configuration of energy storage for integrated re-newable generation plants in the power spot market,which adopts a two-level optimization model of“system simulation+plant optimization”.The first step is“system simulation”which is using the power market simu-lation model to obtain the initial nodal marginal price and curtailment of the integrated renewable generation plant.The second step is“plant optimization”which is using the operation optimization model of the integrated renewable generation plant to optimize the charge-discharge operation of energy storage.In the third step,“sys-tem simulation”is conducted again,and the combined power of renewable and energy storage inside the plant is brought into the system model and simulated again for 8,760 h of power market year-round to quantify and compare the power generation and revenue of the integrated renewable generation plant after applying energy storage.In the case analysis of the provincial power spot market,an empirical analysis of a 1 GW wind-solar-storage integrated generation plant was conducted.The results show that the economic benefit of energy storage is approximately proportional to its capacity and that there is a slowdown in the growth of economic benefits when the capacity is too large.In the case that the investment benefit of energy storage only considers the in-come of electric energy-related incomes and does not consider the income of capacity mechanism and auxiliary services,the income of energy storage cannot fulfill the economic requirements of energy storage investment.

A Study on the Analysis of Load Flow for Railway DC System

Urban railway systems differ greatly from general power systems in that they use direct current(DC)power supply and that the location and power requirements of the loads change.The position and power consumption of the load shall be interpreted continuously every second,or in a fixed unit of time,for a specific period of time during which the operating conditions are repeated.The additional analysis of energy-saving systems being considered as energy efficiency improvement methods requires more complex load flow analysis algorithms.Simulations are performed load flow every time step.The power of an electric railway power feeding system is the power consumed or produced by a train.Because the amount and position of the load change rapidly over time,load flow analysis continues over time.Therefore,based on the method of obtaining solutions by constructing node equations for load flow analysis in this study,load flow analysis was performed through algorithms with energy-saving systems applied.Both thetrain performance simulation(TPS)and power simulation results show that the actual measurement data are estimated almost equally.

基于Buck变换器的扩流电路的研究

提出一种可提高占空比的Buck变换器拓扑结构,相较于传统Buck变换器,该拓扑结构通过改变导通、关断时的电感量,从而改变电路的占空比,提升输出电流。使用Power Simulation软件进行仿真分析的同时,测试一台实验样机。理论分析、仿真验证和实验结果一致,表明该变换器可通过改变占空比来提升输出电流。

Review of Real-time Simulation of Power Electronics

Real-time simulation of power electronics has been recognized by the industry as an effective tool for developing power electronic devices and systems.Since there is no energy transfer during the course of the usage,real-time simulation has a lot of advantages in the process of development and experimentation.From the perspective of real-time simulation,this paper focuses on the main problems in modeling accuracy,system bandwidth and stability,limitations on communication interface and energy interface,and the cost of platform construction.Finally,we provide further research directions.

Real-time impact of power balancing on power system operation with large scale integration of wind power

Highly wind power integrated power system requires continuous active power regulation to tackle the power imbalances resulting from the wind power forecast errors. The active power balance is maintained in real-time with the automatic generation control and also from the control room, where regulating power bids are activated manually. In this article, an algorithm is developed to simulate the activation of regulating power bids, as performed in the control room, during power imbalance between generation and load demand. In addition, the active power balance is also controlled through automatic generation control, where coordinated control strategy between combined heat and power plants and wind power plant enhances the secure power system operation. The developed algorithm emulating the control room response,to deal with real-time power imbalance, is applied and investigated on the future Danish power system model. The power system model takes the hour-ahead regulating power plan from power balancing model and the generation and power exchange capacities for the year 2020 into account.The real-time impact of power balancing in a highly wind power integrated power system is assessed and discussed by means of simulations for different possible scenarios.

Numerical Simulation for FWM Power Evaluation in Optical Fiber Transmission Systems

In order to realize reliable and fast simulation of FWM power evaluation, USSD (Uniform Step-Size Distribution) method is modified and its corresponding simulation results of FWM efficiency and computational time are presented.

Estimating life-cycle energy payback ratio of overhead transmission line toward low carbon development

The energy conservation plays an important role for low carbon development.In order to evaluate the energy conservation in the full life-cycle,a scheme to estimate the energy consumption,or alternatively the energy pay,in constructing an overhead transmission line is proposed in this paper.The analysis of a typical projection is given for demonstration.With new additional overhead transmission lines,the energy consumption,known as the power loss in power network,is expected to be decline,which is defined in this paper as the energy payback.In order to estimate this kind of contribution,the scheme that consisted of load forecast,production simulation for generating systems,load flow simulation and power loss calculation has been proposed.Case studies,based on the IEEE 24-bus test system,are given to demonstrate the efficacy of the schemes.Moreover,several presumptive scenarios are deployed and analysed with the presented schemes for comparison.

A Node Splitting Interface Algorithm for Multi-rate Parallel Simulation of DC Grids

With wider applications of power electronic devices in modern power systems,simulation using traditional electro-mechanical and electromagnetic simulation tools suffer from low speed and imprecision.Multi-rate technologies can greatly improve simulation efficiency by avoiding simulating the entire system using a small time-step.However,the drawbacks of the current synchronization mechanisms is that they introduce numerical errors and numerical instabilities in multi-rate parallel simulations.An improved multi-rate parallel technology,node splitting interface(NSI),is proposed to reduce errors and enhance simulation stability.A new synchronization mechanism is used to avoid prediction and signal delays.Theoretical analyses are carried out to prove the convergence and absolute stability of the proposed NSI algorithm.This algorithm is particularly suitable for simultaneously investigating long term dynamics of DC grids and fast transients of power electronic converters.