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DIgSILENT PowerFactory Technical Reference Documentation...

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DIgSILENT PowerFactory Technical Reference Documentation

Sample and Hold ElmSamp

DIgSILENT GmbH Heinrich-Hertz-Str. 9 72810 - Gomaringen Germany T: +49 7072 9168 0 F: +49 7072 9168 88 http://www.digsilent.de [email protected] Version: 2016 Edition: 1

Copyright © 2016, DIgSILENT GmbH. Copyright of this document belongs to DIgSILENT GmbH. No part of this document may be reproduced, copied, or transmitted in any form, by any means electronic or mechanical, without the prior written permission of DIgSILENT GmbH. Sample and Hold (ElmSamp)

1

Contents

Contents 1 General Description

3

2 Dynamic Simulation

3

3 Example Configuration

4

A Parameter Definitions

7

B Signal Definitions

7

List of Figures

8

List of Tables

9

Sample and Hold (ElmSamp)

2

2

1

Dynamic Simulation

General Description

Analog signals can not be connected to digital signal processing modules directly. The analog signal must be sampled first. Usually a sample and hold module is setting the output at the rising edge of the clock signal. The output value is constant up to the next clock pulse. The Sample and Hold model of PowerFactory is providing exactly this functionality. In the following S&H denotes Sample and Hold. In PowerFactory the S&H model will produce the following output.

1.20

cl2 x= 1.4500 s

cl3 x= 1.5500 s

1.0726

DIgSILENT

cl1 x= 1.3500 s

1.60

1.0130 0.8135

0.80 0.40 0.0007

0.00

0.0007

0.0008

-0.40 1.30

1.40 Sample & Hold: Input Signal

1.50

1.60

[s]

1.70

[s]

1.70

Clock: Output 1.60 1.20 0.80 0.40 -0.00

1.3500 s 1.0726

-0.40 1.30

1.4500 s 0.8135 1.40

1.5500 s 1.0130

1.50

1.60

Sample & Hold: Output Clock: Output

Figure 1.1: Plot Sample & Hold Output In the example given in 1.1 the clock period is 100 ms. The upper plot shows the input signal of the clock. The plot on the bottom shows the output signal. At every rising edge of the clock pulse the input of the S&H model is read and written to the output. The intersection point between the vertical bars in the upper plot and the curve show the sampled value. The output of the S&H model is constant up to the next rising edge of the clock.

2

Dynamic Simulation

The input signals input and cl must always be connected for using the model in the simulation. input A, input B and input C need not to be connected. Input values not connected are set to 0.

Sample and Hold (ElmSamp)

3

3

Example Configuration

Single Phase

Three Phase input_A

output_A

input_B

output_B

input_C

output_C

input

output

cl

cl

Figure 2.1: Input/Output Definitions

3

Example Configuration

Figure 3.1 shows a typical configuration for the use of the S&H model. An analog signal is connected to the input of the S&H model. The output of the S&H is the connected to the input of a register (ElmReg). The size of the register is one. Both, the register and the S&H model are connected to the same clock source. The plots show input and output of the S&H model and the output of the register.

DIgSILENT

Due to the register size of one there is a delay of one clock period between the input and the output of the register.

Sample & Hold + Register:

cl Clock ElmClock

0

0

input Input File ElmFile

Sample & Hold ElmSamp

Register ElmReg 1

1

Figure 3.1: Block Diagram

Sample and Hold (ElmSamp)

4

3

Example Configuration

Table 3.1: Example settings Element

Classname

Variable

Value

Initial Conditions

ComInc

Clock

ElmClock

Sample & Hold Register

ElmSamp ElmReg

iopt sim iopt net dtgrd and dtout tstart cFreq Tp tonTp nphase nphase nsamp iopt mod

RMS values (Electromechanical Transients) Balanced, Positive Sequence 0.05 ms 0.05 ms 0.01 kHz 100 ms 0.5 1 1 1 Register

Sample and Hold (ElmSamp)

5

Example Configuration

cl1 x= 1.350 s

1.60

cl2 x= 1.450 s

cl3 x= 1.550 s

cl4 x= 1.650 s

DIgSILENT

3

1.272 1.20

1.073

1.013 0.813

0.80

0.40 0.001

0.00

0.001

0.001

0.001

-0.40 1.30

1.40

1.50

1.60

[s]

1.70

Sample & Hold: Input Signal Clock: Output 1.60 1.350 s 1.073

1.450 s 0.813

1.550 s 1.013

1.650 s 1.272

1.20

0.80

0.40

0.00

-0.40 1.30

1.40 Sample & Hold: Output

1.50

1.60

[s]

1.70

Clock: Output 1.60 1.450 s 1.073

1.550 s 0.813

1.650 s 1.013

1.20

0.80

0.40

0.00

-0.40 1.30

1.40

1.50

1.60

[s]

1.70

Register: Output Clock: Output

Figure 3.2: Example plots

Sample and Hold (ElmSamp)

6

B

A

Signal Definitions

Parameter Definitions Table A.1: Sample and Hold Parameters

B

Parameter

Description

Unit

loc name outserv nphase

Name Out of service Number of phases

Signal Definitions Table B.1: Input/Output signals Name

Description

input A input B input C input cl output A output B output C output

Input Input Input Input signal Clock signal Output Output Output Output signal

Sample and Hold (ElmSamp)

Unit

Type

Model

IN IN IN IN IN OUT OUT OUT OUT

RMS, EMT RMS, EMT RMS, EMT RMS, EMT RMS, EMT RMS, EMT RMS, EMT RMS, EMT RMS, EMT

7

List of Figures

List of Figures 1.1 Plot Sample & Hold Output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3

2.1 Input/Output Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4

3.1 Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4

3.2 Example plots . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

6

Sample and Hold (ElmSamp)

8

List of Tables

List of Tables 3.1 Example settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

5

A.1 Sample and Hold Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

7

B.1 Input/Output signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

7

Sample and Hold (ElmSamp)

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