PSCAD是一种有效的用户图形界面,能够显著地提高电力系统电磁暂态模拟研究的效率。利用PSCAD 家族的软件工具,使得电力系统工程师能够充分利用现代微机工作站的资源, 更为有效地使用马尼托巴高压直流研究中心的EMTDC 暂态模拟软件。该族软件还可作为该中心的实时数字模拟器(RTDS)的用户界面。
PSCAD 由下述软件模块构成:
文件管理系统
当用户涉及PSCAD 时所遇到的第一个软件模块就是文件管理系统。采用一种工程/算题/文件的分层结构来表示用户进行电力系统模拟研究的数据库结构。如果得到授权可以进入该数据库, 这样, 局部网上的不同用户可以共享同一个数据库。从文件管理软件模块可以直接进行诸如备份、储存、文件编缉、拷贝和删除等操作。 通过选择文件管理模块屏幕右上角的适当菜单可调用PSCAD 的其它软件模块, 很多情况下将所有的软件模块同时激活, 有些模块的图像可能暂时隐藏在正在处理的模块图像之下。
建模(DRAFT)模块
建模程序包是PSCAD 程序族中最有功效的。借助建模包, 用户可以用图形的方法建立需要进行模拟研究的电力系统模型。通过选择不同的功能, 建模包可以为EMTDC 或RTDS模拟研究准备必需的文件。
电力系统元部件图像位于调色板中(建模窗口的右侧)并可移至画布上(左侧), 通过将各元部件模型互连便
完成了电力系统模型。不同元部件模型所需的参数可在调用这些模型时屏幕上出现的菜单中直接输入。具有大量互联元部件的电力系统模型同样易于处理, 因为画布部分可分为很多层次并可在屏幕上滚动显示。当用户完成了模型构筑时, 可以通过基于PS格式的激光打印机或者可以接受HP-GL 命令的绘图仪输出硬拷贝。
架空线(T-LINE)和电缆(CABLE)模块
确定架空输电线和电缆的行波模型所需数据的计算过程是相当复杂的。为了确定变换矩阵、模式传输时间和波阻抗, 需要进行特征值分析。为了完成这种分析, 需要使用T-LINE和CABLE 模块。通过功能选择可以产生单频率模式模型或者完全的频率相关行波模型。
架空线模型所需要的数据有导线的空间相对位置以及导线的半径和电阻率。对于电缆, 每一导电层和绝缘层的半径和特性都是必需的。由T-LINE和CABLE 模块所产生的数据可以直接输入到PSCAD 的建模(DRAFT)模块中。
运行(RUN TIME)模块
运行模块中的EMTDC 操作员控制台软件模块和RTDS控制台软件模块可分别为运行EMTDC和RTDS提供控制操作功能和数据收集系统功能。软件中提供了完善的界面, 允许使用者装入、启动或停止一个模拟算题, 并可在模拟过程中与之通讯。由于采用了多种仪表和模拟过程数据在线绘图, 允许使用者获得相关模拟算题的即时反馈。使用者所激发的动态过程, 如整定值改动、开关操作以及故障触发可以通过操纵滑触头、电位器、开关和按钮进行。
单曲线绘图(UNIPLOT)和多曲线绘图(MULTIPLOT)模块
EMTDC 和RTDS所产生的数据的分析和绘图是通过单曲线绘图模块进行的。可以对数据进行标尺整定和通用格式整定。对于绘图用的数据可直接进行傅里叶分析。如果要处理大量的数据, 可以通过编程的办法形成自动处理顺序。 多曲线绘图模块可以将单曲线绘图模块绘出的曲线整理成适合报告应用。可将多根曲线组合安排在单张纸上。使用者可以直接处理曲线并在纸面上添加需要的文字说明并可绘制其它美化标志。
EMTDC
EMTDC 是一套基于软件的电磁暂态模拟程序, 可以通过PSCAD 进行调用。用户可以通过调用随EMTDC 主程序一起提供的库程序模块或利用用户自己开发的元部件模型有效地组装任何可以想象出的电力系统模型和结构。EMTDC 的威力之一是可以较为简单地模拟复杂电力系统, 包括直流输电系统和其相关的控制系统。
利用EMTDC可进行的模似研究范围为:
一般的电力系统电磁暂态研究
直流输电结构和控制
FACTS(灵活交流输电系统)元部件模型
同步发电机和感应电动机的扭矩效应和自励磁研究
静止补偿器研究
非线性控制系统研究
变压器饱和研究, 如铁磁振荡和铁芯饱和不稳定性研究
绝缘配合研究
谐波相互影响研究
新型控制系统原则的开发
陡前波分析
从开始到完成一次EMTDC 算题包括如下步骤:
1) 利用文件管理系统生成一个工程和算题名
2) 利用建模模块建立电力系统模型
3) 利用运行模块进行EMTDC 模拟计算
4) 通过单曲线绘图对模拟结果进行分析并利用多曲线绘图模块产生可直接用于研究报告的模拟结果图形
RTDS
应用并联数字处理技术构成实时数字模拟器(RTDS)。EMTP和EMTDC 这些软件中所采用的著名电磁暂态求解方法同样在RTDS中采用以模拟电力系统。
通过联合使用RTDS硬件和PSCAD 软件开发了一种模拟器, 用以模拟包含高压直流输电系统的大型互联电力系统。可以将实际的直流控制系统与这种模拟器互联以便进行系统调试前的模拟试验或者帮助工程师们熟悉新的控制概念。
RTDS和PSCAD 的结合还用于实际继电器的闭环试验。通过对模拟器模拟量通道的电压和电流信号的放大可以模拟系统故障并观察继电器的响应, 继电器的触头可用来触发模拟器中的开关动作。
联网和工业标准
由于PSCAD 严格遵守工业标准, 如UNIX、以态网、PS图形方式和X窗口标准, 确保这一软件能在不同的微机工作站上运行。借助局部网技术使得用户可进入一个通用的数据库。一位用户进行的模拟研究的数据和结果可由另外的用户调用,如果后者得到了适当的授权的话。
除了可使用通用数据库外, 还可以在用户间共享计算机资源。PSCAD 设计中采用了专门的技巧, 允许高性能的网络服务器或轻载的工作站被安排用作大量的数据模拟计算,而用户工作站可以用来准备新的模拟算题或进行实际模拟的结果监视。从PSCAD 还可以直接享用诸如打印机和绘图仪之类的资源。
硬件要求
PSCAD 编写使其适合在基于UNIX操作系统并具有X 窗口环境的微机工作站上运行。PSCAD 具备自己的软件支持因而不需要用户再安装其它支持软件。 建议使用的系统至少应具备16MB的内部RAM。 安装的PSCAD 软件需占用不到10MB的磁盘存储空间。软件同时支持单色和彩色监视器。如果要运行EMTDC 模拟软件, 用户应提供FORTRAN 77(F77) 编译器。硬拷贝输出采用PS格式。建模模块中的图形可通过接受HP-GL 命令的绘图仪输出。

PSCAD is an effective user interface and can significantly improve the efficiency of electromagnetic transient simulation of power system.

The PSCAD family of software tools enable power system engineers to make full use of the resources of modern microcomputer workstations and more effectively use the EMTDC transient simulation software of Manitoba HVDC research center. The software can also serve as a user interface for the center's real-time digital simulator (RTDS).

PSCAD is composed of the following software modules:

File management system

The first software module that users encounter when involving PSCAD is the file management system. A hierarchical structure of engineering/calculation/files is used to represent the database structure of power system simulation research conducted by users. If authorized, the database can be accessed so that different users on the local network can share the same database. From the file management software module, operations such as backup, storage, file editing, copy and delete can be performed directly. Other software modules of PSCAD can be invoked by selecting the appropriate menu in the upper right corner of the file management module's screen. In many cases, all software modules are activated at the same time.

The modeling (DRAFT) module

The modeling package is the most effective of the PSCAD family of programs. With the help of the modeling package, users can use the graphical method to build the power system model that needs to be simulated. By selecting different features, the modeling package can prepare the necessary files for EMTDC or RTDS simulation studies.

The power system component image is located in the palette (right of the modeling window) and can be moved to the canvas (left) by interconnecting the component model

The power system model is completed. The parameters required by the different component models can be entered directly from the menu that appears on the screen when these models are invoked. The power system model with a large number of interconnected components is also easy to handle because the canvas section can be divided into many layers and scrolled across the screen. When the user has completed the model construction, hard copies can be output through the laser printer based on PS format or the plotter that can accept the hp-gl command.

T-LINE and CABLE modules

The calculation process of the data required to determine the traveling wave model of overhead transmission lines and cables is rather complicated. In order to determine the transformation matrix, mode transmission time and wave impedance, eigenvalue analysis is needed. In order to complete this analysis, the t-line and CABLE modules are required. A single frequency mode model or a complete frequency-related traveling-wave model can be generated by function selection.

The data required for the overhead line model include the spatial relative position of the conductor, the radius of the conductor and the resistivity. For cables, the radius and characteristics of each conductive layer and insulation layer are required. The data generated by the t-line and CABLE modules can be directly input into the PSCAD's DRAFT module.

RUN TIME module

The EMTDC operator console software module and RTDS console software module in the running module can respectively provide control operation function and data collection system function for running EMTDC and RTDS. The software provides a sophisticated interface that allows the user to load, start, or stop a simulation and communicate with it during the simulation. The use of a variety of instruments and simulation process data online mapping allows users to obtain real-time feedback on relevant simulation calculations. The dynamic process triggered by the user, such as setting changes, switching operations and fault triggering, can be performed by manipulating the sliding contacts, potentiometers, switches and buttons.

Single curve plot and MULTIPLOT modules

The analysis and drawing of data generated by EMTDC and RTDS is carried out through the single curve drawing module. Data can be calibrated and general format set. The data used for mapping can be directly analyzed by Fourier analysis. If you want to process large amounts of data, you can programmatically form an automatic processing sequence. The multi-curve drawing module can arrange the curve drawn by the single-curve drawing module into a suitable report application. Multiple curves can be combined on a sheet of paper. Users can directly process the curve and add the required text description on the paper surface and draw other beautification marks.

EMTDC

EMTDC is a software based electromagnetic transient simulation program, which can be called through PSCAD. The user can effectively assemble any power system model and structure imaginable by calling library modules provided with the EMTDC master program or by using the meta-component model developed by the user himself. One of the strengths of EMTDC is its ability to more easily simulate complex power systems, including dc transmission systems and their associated control systems.

The research scope of the simulation using EMTDC is as follows:

General electromagnetic transient study of power system

Dc transmission structure and control

FACTS(flexible ac transmission system) component model

Study on torque effect and self excitation of synchronous generator and induction motor

Study of static compensator

Nonlinear control system study

Transformer saturation studies, such as ferromagnetic oscillations and core saturation instability studies

Insulation fit study

Study on harmonic interaction

Development of new control system principles

Steep front wave analysis

From the beginning to the completion of the EMTDC calculation, the following steps are included:

1) use the file management system to generate an engineering and calculation title

2) use the modeling module to establish the power system model

3) EMTDC simulation calculation was conducted by using the operation module

4) analyze the simulation results through single curve drawing and generate simulation results graphics that can be directly used in research reports by using multi-curve drawing module

RTDS

Real - time digital simulator (RTDS) is constructed by using parallel digital processing technology. The well-known electromagnetic transient solution methods used in EMTP and EMTDC software are also used in RTDS to simulate power systems.

A simulator was developed using RTDS hardware and PSCAD software to simulate large interconnected power systems including HVDC systems. The actual dc control system can be interlinked with the simulator to conduct simulation tests before system commissioning or to help engineers familiarize themselves with new control concepts.

The combination of RTDS and PSCAD is also used in actual relay closed-loop testing. By amplifying the voltage and current signals of the analog channel of the simulator, system failures can be simulated and the response of the relay can be observed. The contact of the relay can be used to trigger the switching action in the simulator.

Networking and industrial standards

Because PSCAD adheres strictly to industrial standards such as UNIX, state grid, PS graphics, and X window standards, it ensures that the software can run on different microcomputer workstations. Local network technology allows users to access a common database. The data and results of a simulation study conducted by one user can be invoked by another user if the latter is properly authorized.

In addition to a common database, computer resources can be Shared between users. PSCAD designs employ specialized techniques that allow high-performance network servers or lightly loaded workstations to be scheduled to be used for large amounts of data simulation calculations, while user workstations can be used to prepare new simulation calculations or to conduct actual simulation results monitoring. Resources such as printers and plotters are also available directly from PSCAD.

Hardware requirements

PSCAD is written to make it suitable for running on a microcomputer workstation based on the UNIX operating system with an X window environment. PSCAD has its own software support so that users do not need to install additional support software. The recommended system should have at least 16MB of internal RAM. The installed PSCAD software requires less than 10MB of disk storage space. The software supports both monochrome and color monitors. If you want to run EMTDC simulation software, you should provide a FORTRAN 77(F77) compiler. Hardcopy output is in PS format. The graphics in the modeling module can be output by the plotter receiving the hp-gl command.