Dear Saad,

I have been involved in design of such an LCC thyristor inverter control system ca 25 years ago. This should use phase control. If you could share the circuit diagram, it might be possible to say why the capacitors are needed and how to control them.

Best regards,

Jüri

This is the circuit diagram file. This would help you in making of Converter Circuit and to control it. Plus, could u also checkout the output waveforms of both rectifier and inverter sides, before implementing converter into it? Jüri Joller

Thanks

Could you send me pdf or similar file I could open without PScad. BR Jüri

I have attached pdf form of our model. In this you can see the main circuit plus rectifier side and inverter side Jüri Joller

Jüri Joller Sir please guide us i have sent you pdf files as you require

Dear Saad,

The AC capacitors seem to be some kind of harmonic filter. If you put just pure capacitance there you might get modelling problem. As you know, the capacitor has always certain parasitic resistance and inductance.

To switch these harmonic filters, you should need to know the harmonic content of your AC voltage and current over the load area.

Br. Jüri

Respected Jüri Joller

I got your point about the AC capacitors. What can we do next, so that it can be completed? "We need to attach the polarized capacitor instead of unpolarized." Is this what you are trying to say? Also, please elaborate the remedy in simple way.

Saad

Dear Saad, on AC side you can use unpolarised AC capacitors only according to my knowledge. I was trying to say that especially the capacitor 3.342 uF may cause modelling problems, in case you do not model its initial voltage, parasitic resistance and inductance.

You have huge high voltage converter system. I am quite sure, you should have also it´s documentation. BR Jüri

Respected Jüri Joller

The capacitor of 3.342 uF isn't affecting much kind of modelling problems. Also sir, I know about it too that we have high voltage converter system. As far as documentation is concerned, we haven't prepared it yet, unless we don't complete the model and control of converter circuit. BTW, I have sent a research paper related to this project. You can take guidance from that. I have shared it again.

But before this, as far as we have done our project so far, there is an issue in graph of DC voltage and current and I have come to know that it is related to gate pulses problem. Please, take a look at that point too.

Saad

Dear Saad, the article "Elimination of Commutation Failures of LCC

HVDC System with Controllable Capacitors" describes a different converter system as your model. This is very different converter, I think. This may have commutation problems due to controlled capacitors. In a classical thyristor line controlled inverter you need to guarantee that the thyristors have reversed voltage during recovery time tq. It means the gating angle shall be limited to 180o - recovery angle - commutation angle. BR Jüri

Respected Jüri Joller

I got your point about thyristor line controlled inverter. My point is that, will it be possible for you sir to help or guide us completing this project?

Saad

Dear Saad, thank you for your proposal. I must say that I am currently overloaded with different engineering projects. Therefore, I can not promise anything to you. Could you please describe your project aims, time-schedule etc. My email is [email protected] .

BR Jüri Joller

Respected Jüri Joller

Sir, I appreciate that u have considered the situation and condition of my project. Actually, now I have implemented some other converter circuit on PSCAD. But this time, many errors are being displayed and I have negligible idea of how to fix them. Now, I am concerned with two conditions:

1. In first case, I really want to improve the DC pulse train of both rectifier and inverter sides of HVDC system before implementing converter circuit.

2. After that, I really want the errors of Implemented Converter Circuit to be fixed, so that this will be end of our project.

I m sending u attached files of my work done so far to your email id. Sir, It will be highly appreciated for all of my groupmates, if u consider our situation and resolve it.

The 2 points are our project aims and time-schedule to submit it is after that week. Therefore, It is requested sir to please help me completing this project.

Thanks in advance

Saad

Dear Saad,

as I understand, this is kind of a student project that you need to resolve yourself with your team and your professor.

Best regards, Jüri

Respected Jüri Joller

Its basically our Final Year Project. And by the way, my professor has recommended me to seek some academic help from online platform as well. That's why, I am posting the queries of my project on that platform. It will be appreciated sir, If you help me complete this.

Thanks alot

Saad

Respected Jüri Joller

I have also sent some files and related queries to your email id.

Saad

Dear Saad,

I am not academic since 2004. I am from industry.

BR Jüri