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)
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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)
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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)
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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)
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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
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List of Figures
List of Figures 1.1 Plot Sample & Hold Output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3
2.1 Input/Output Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4
3.1 Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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3.2 Example plots . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6
Sample and Hold (ElmSamp)
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List of Tables
List of Tables 3.1 Example settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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A.1 Sample and Hold Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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B.1 Input/Output signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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Sample and Hold (ElmSamp)
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