PSCAD 4.2 说明文件

PSCAD/EMTDC 4.2.0

November 18, 2005

Welcome to PSCAD/EMTDC V4.2. Version 4.2.0 is available as a complete install only and

can be installed alongside existing installations of PSCAD V3, V4.0.X and V4.1.X

There exist two separate installs, one for Professional/Educational and one for

Student/Evaluation Versions of PSCAD.

Important Note

Blank Parameter Fields:

When a component parameter field is undefined, earlier PSCAD

compiler versions assumed a value of '0.0', a real number. This assumption is potentially

risky since no real number was actually entered. By design in PSCAD V4.2, the compiler will

no longer accept indeterminate input values and resolves to 'NaN' (see parameter viewing

dialog). This produces a compiling error and will not run the case. The user model must have

a valid default if the user does not enter anything. This may require previous version PSCAD

model maintenance if defaults were neglected in the original design. More information on

this item can be found by visiting

/view_?id=466&forum_id=14

Windows XP Professional x64 Edition

: If you want to run PSCAD 4.2.0 Professional or

Educational on Windows XP Professional x64 Edition, you must configure PSCAD to get a

license from a License Manager on another machine, or use a lockless trial license. The 32-

bit Sentinel lock drivers supplied with the PSCAD and LM installers will install on XP 64, but

will not run, so neither the License Manager nor PSCAD will be able to detect USB or parallel

port locks.

Correctly Uninstalling PSCAD 4.2.0:

Use the Add/Remove Programs control panel to

properly uninstall (remove) PSCAD 4.2.0. If you browse to the PSCAD CD and start

and then select Remove, the uninstall process will remove all registry keys

required by other installed versions of PSCAD V4. Should this happen, you need to repair

the remaining installed versions of PSCAD V4.

Known Issues

1)

The Hardware Key Rainbow USB driver version 7.71.9 does not properly support

Hibernation/standby. The older version 5.39.6 Sentinel drivers properly detected the lock

after waking up from hibernation & suspend modes, however there may be other driver

conflicts with installed software. The new 7.71.9 drivers do not detect the lock after waking

up from hibernation & suspend modes unless you unplug & replug in the lock. Sentinel says

that this issue will be fixed in their next driver release due late Nov. 2005. At that time we will

test the new drivers, and then deploy a patch through our support website.

2)

If you have two UMEC transformer instances in one case, where the first instance

the saturation is disabled, and the second transformer saturation is enabled, the saturation

parameters will affect the first UMEC component. The quick workaround is to disable the

saturation of both transformers, or enable the saturation of both transformers. This will be

fixed with the next maintenance release.

PSCAD Improvements

In this section we have compiled a collection of brief overviews of individual changes to the

architecture of PSCAD. The following items are not listed in any particular order, but provide

some detail as to the nature of the change and how it may impact current users.

Unit Conversion System:

Unit conversion has been a high demand item for development in recent months. A new

system has been integrated to perform automatic unit conversion. This function is a table

based conversion utility build into the data manipulation code for the components. It operates

as a separate object design to accept input as a source unit and convert to a defined target

unit. It is important to note that there are 3 basic types of units conversion identified. They

are:

1) Direct proportional conversion (i.e. metre >> feet)

2) Translational conversion (i.e. Celsius >> Fahrenheit)

3) Domain inverse relationship (i.e. sec >> Hz)

The unit conversion system implements the first form of conversion only. Proportional

conversion has a common intercept point through zero and thus does not require the input

value to provide a conversion ratio. In addition the conversion is capable of handling multiple

terms as long as both the count and operator sequence match. An example of this is the

conversion of [ohm/m*s] to [kohms/ft*s] where both the source and target units specification

contain the same number of terms (3) and the same operator sequence (/*).

Scaling factors prefixes are included in engineering factors of 10

3

each from pico(-12) to

giga(+12). Scaling factors can not be combined in accordance to SI standards and are

limited to 10e

±

12

.

Operator precedence is always left to right. Precedence control symbols '(' and ')' are not

supported. Power terms are support with a “^” symbol, i.e. kg/m^3 w

ould be kilograms per

cubic meter.

Literal terms are supported in a limited fashion. This allows for units to be specified as [1/s]

for example, or even [3.14/s]. Literals can not contain a sign or any exponential as this is

ambiguous with operators.

If a conversion cannot be performed the system will return an indeterminate factor

represented by #NaN which is then handled by the error messaging system. If the source

equals the target the behaviour is unity (of course). If either unit is not specified then the

default behaviour is unity (1.0). This behaviour is irregardless of an existing unit having

literals or not.

It is also possible to successfully convert units that are represented by common alias terms if

they are provided in the database. Typical examples of this are [Hz] as an alias for [rev/s]

and [rpm] as an alias for [rev/min]. Support for aliasing extends to single term unit

specifications only. Multipliers are legal, so the term [kHz] will correctly convert to the

compound term [krev/s]. This is possible since the multiplier is handled separately from the

base unit.

To support the units conversion object a new XML data file () is included. This file

must be placed in the home directory.

It is important to note that this system was developed using the

National Institute of

Standards and Technology

as a reference on SI. The implementation is partial and is

intended for use in electromechanical systems. The reference can be found at:

SI Standards Reference: <>

Phasor Meter Devices:

A new device have been add to the latest build of PSCAD to support complex pairs of

Magnitude and Phase Angle created by the FFT component and others. The device displays

instantaneous vectors (magnitude and angle) from the origin in the form of a thick line. If the

magnitude exceeds 1 pu of the display an arrow is attached to the line to indicate it is out of

scale. The display device will show either a single phasor or up to six phasors in an

adjustable gauge display. Numerical values for the magnitude and phase angle are given at

the footer panel of the device. The input can be toggles to accept values in either radians or

degrees.

Navigation History Bar:

Users no longer need to try and retrace their steps by memory alone. A new Navigation Bar

has been added to PSCAD that automatically tracks navigation within a project space.

By design the style of navigation is using the same methodology that is commonly found in

the Windows Explorer. As you move from one module definition to another, the history list is

appended with each movement. This list is split at the current navigation point, filling the drop

list next to the 'Forward' / 'Backward' buttons. User can move incrementally or by selecting a

location directly.

This system has significant benefit for large control system architectures where levels of

detail may be nested several modules down from the top. Navigation through these complex

cases is much simpler with a history control.

Global Substitutions:

Substitutions are well defined for definitions and widely used. These operate using input data

as a source, while using the definition to define the actions. This means that all components

of a certain type will process substitutions in the same way. If substitutions are required on a

per instance basis, then this process cannot be used. Early implementations of and instance

based substitution was called a global constant and allowed the user to enter a defined text

string. This was then inserted as a value into an input field of a user component, but was

limited for many other actions.

This mechanism has been reworked and the concept of a global constant has been replaced.

The big difference with the new approach is the process is completely general and does not

require that a defined substitution be a numerical type. This allows for raw text substitutions

combing both pre-fix and post-fix patterns. The syntax is the same as used for definitions as

follows:

$$()

There is no context key since the context is always that of the project. This text will be

substituted at any point where a user component accesses its raw data. The raw data will be

pre-processed with the substitution before it is returned for use. This allows the substitution

to act exactly as if the user entered that data into the parameter field. There is a small

computation overhead to achieve this flexibility.

Note: V4.1 implementation of Global Constants will no longer function and occurrences will

need to be replaced with the above syntax. This was necessary since the constants were

devoid of formal syntax, creating difficulties in resolution.

Automatic Computations:

Parameters are constants that are initialized in input fields. Computations are constants that

are calculated from those parameters and/or other computations. Originally the computations

were processes at the time a circuit module was compiled. This meant that none of the

computed constants were available when a component is placed on the canvas

.

Changes

have been made to the way in which a user component handles its computations. They are

now processed in the layout procedure of the user component prior to the evaluation of the

graphic flags and dynamic text in the component. In this sense they are automatically

computed with the component and always remain available and up to date.

More importantly, computations are now available for both graphic substitution and visibility

expressions allowing the user to place a computed value on the display. This value will be

undated whenever the component is placed on the canvas. Computations can also be

created anonymously (no name identity attached) and used in the component. The

anonymous expression substitution syntax:

$${}

This syntax, although perfectly valid, is no longer required to perform dynamic computation

text for graphics since the expression can be defined by a computation and substituted into

the display like any other parameter.

Extended Substitution Syntax:

In an effort to standardize the substitution syntax, the parser has been extended to include a

more formal way of handling substitution

from

other contexts. This comes from the need to

pull information from more than just the component instance data. The standard syntax is:

$$(:)

Where the substitution contains both a and item that are separated by a

scope operator and delimited by round brackets. This syntax is intended to be standardized

within the application to avoid multiple ways of performing substitutions. The name of the

context allows the parser to insert information from objects outside of the scope of the

component instance. These are:

Defn, Project, Work, Session and System.

When use for substitution within the context of the component instance, there is no need for

a context and it is excluded along with the scope operator. In such cases the syntax is:

$$() or... $$

This syntax is backwardly compatible with existing installations and the simple un-delimited

form is the one that is use in most cases. (Both forms are now legal). The delimited version