Modeling an earthing switch for a High Voltage Impulse Generator

In summary, the paper discusses the modeling of an earthing switch used in high voltage impulse generators, focusing on its electrical characteristics and operational behavior. It highlights the importance of accurate modeling for ensuring safety and reliability in high voltage applications. The study employs simulation techniques to analyze the switch's performance under various conditions, providing insights into its efficiency and response to impulse voltages. The findings aim to enhance the design and functionality of earthing switches in power systems.
  • #1
Angus Fergusson
2
0
TL;DR Summary
Modelling a seemingly simple mechanism that is proving to be quite challenging
Hi All,

I am trying to model this mechanism for a project. It is a switch that uses a solenoid to break the contact by lifting the aluminium arm. I understand that there is most likely software out there that can do this but i would like to understand how to model this from first principals.

I have got a function for the force on the armature of the solenoid from an electromagnetic modeling software. The force on the armature is the input to the system. I want the motion of the armature, Y, as the output of the model.
So far I have found Y and its derivatives in terms of theta and beta which are the angle of the link 2 (crank) and the angle of link 3 (con rod), respectively. I have also found beta and its derivatives in terms of theta (meaning that i effectively have Y in terms of theta). After that there is the force balance on each link. I have left friction on the armature out for now, F_mu.

At the moment I am struggling with creating the equations of motion of the armature (Ydotdot = TotalForceOnArmature/MassOfArmature). Any help would be greatly appreciated

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Thanks in advance!
 
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  • #2
Welcome to PF.
Angus Fergusson said:
I have got a function for the force on the armature of the solenoid from an electromagnetic modeling software. The force on the armature is the input to the system. I want the motion of the armature, Y, as the output of the model.
I assume the white arm is the earthed contact arm, and it is attached to the elbow link.
All points in the linkage appear to travel in circular arcs, except the solenoid, which moves in a straight line.

The arc through which the white arm travels, restricts the range that must be modelled.

Are you modelling the dynamic flight of the arm as a result of the predicted solenoid force, or the static force required to move the arm through, or to hold the arm in a particular position?
 
  • #3
Originally tried to do the dynamic flight but found the algebra for that to be far too complicated. I considered a state-space approach but do not have enough knowledge to pull that off. Ended up just doing a static force analysis to find the friction between the solenoid armature and the housing, which was then iterated to get the friction as a function of the position of the armature in the solenoid housing.

And yes you are correct with the mechanics of the linkage.

The model is no longer needed but I would love to hear if there is a better approach to the problem.
 

FAQ: Modeling an earthing switch for a High Voltage Impulse Generator

What is the purpose of an earthing switch in a high voltage impulse generator?

An earthing switch in a high voltage impulse generator is used to safely discharge the stored energy in the generator's capacitors after a test or in case of an emergency. This prevents accidental electric shocks and protects equipment from damage due to residual high voltage.

How do you model the electrical characteristics of an earthing switch?

To model the electrical characteristics of an earthing switch, you need to consider its resistance, inductance, and capacitance. These parameters can be derived from the physical dimensions and materials of the switch. The switch's behavior under high voltage and high current conditions should also be simulated to ensure reliable performance.

What software tools are commonly used for modeling an earthing switch?

Common software tools for modeling an earthing switch include MATLAB/Simulink, PSCAD, and EMTP-RV. These tools allow for detailed simulation of electrical circuits and can handle the complex interactions between components in a high voltage impulse generator system.

What are the key parameters to consider when designing an earthing switch for a high voltage impulse generator?

Key parameters to consider include the switch's voltage rating, current rating, switching speed, mechanical durability, and thermal performance. Ensuring that the switch can handle the high voltage and high current levels typically encountered in impulse testing is crucial for reliable operation.

How do you test the performance of an earthing switch in a high voltage impulse generator setup?

Testing the performance of an earthing switch involves subjecting it to high voltage and high current conditions similar to those it will encounter in actual use. This includes impulse voltage tests, mechanical endurance tests, and thermal performance tests. The switch's ability to safely discharge energy and return to a safe state should be thoroughly evaluated.

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