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Reference Number: AA-01346// Views: AA-01346// Created: 2017-11-27 21:35:40// Last Updated: 2019-12-26 20:36:52
HowTo
How to use the "Dynamic load" block in Hypersim Windows?

How to use the "Dynamic load" block in Hypersim?

This Knowledge Base article is intended to solve some doubts that may arise when using the  "Dynamic Load" block in Hypersim Windows. This KB is not meant to replace the detailed Hypersim documentation available, but instead to give further details on specific features of the block.

1) When the “Dynamic Load Status” is set to “Disable”: what happens? 

When the “Dynamic Load Status” is set to “Disable” this only disables the dynamic part of the load but the static part remains connected to the circuit, as shown in Figure 1, where the red rectangles indicate the "dynamic part " of the load, while the black rectangle indicates the "static part" of the load.


Figure 1: Dynamic and static parts of the "Dynamic Load" block


A simple model can be downloaded at the bottom to verify this. The Dynamic Load block in the model is set to "disabled", however the 100 ohm shunt static resistance of the block still consumes around 1.9 MW (same as the "Ld1" shunt resistance ), Figure 2 shows this configuration. 



2) The option “Measuring Filter status” applies a “Butterworth” filter to the voltage value “U” at the terminal of the Dynamic load (i.e. its Point of Common Coupling  with the electric network). The filter has a pass-band tuned at 50-70 Hz, see Figure 3. The "U" voltage is the actual voltage of the Dynamic load block which in turn is used to calculate the actual PQ values of the dynamic load (Figure 4) as a function of nominal values (Q0, P0, f0) and measured values (P, Q, f). This filter is necessary since the PQ equations work for nominal frequency of 60 Hz.

Figure 3: Measuring filter for dynami load voltage "U"



Figure 4: Power expressions to determine the P and Q values of the dynamic load.


3) What is the bibliographic reference from which the dynamic load is created?
 
The operation of a dynamic load model is not straightforward. Interested users can find the theory behind it and further details  in these two references:
 
[1] «Power System Stability and Control» by P. Kundur, Mc Graw Hill book, 1993
[2] «Load Representation For Dynamic Performance Analysis» by IEEE task force on Load Representation for Dynamic Performance, IEEE paper 1992 WM 126-3 PWRS


4) Limitations of the dynamic load

The dynamic load is modelled in DQ reference frame and then converted to 3-phase reference system. Because of this, when performing connection/disconnection of a dynamic load though a 3-phase breaker, user should perform the exact same maneuver in the 3-phases of the breaker since the dynamic load would not respond correctly to individual 1-phase operation maneuvers.  




DYNAMIC_LOAD.rar 16.8 Kb 16.8 Kb