Simulation of an earth fault with the aid of an earth fault quenching coil

Hello all,

I would like to simulate an earth fault in a 10.5kV network. To do this, I have built a system and calculated and set all the parameters. The system consists of a source (30kV), transformer (30/10.5kV), medium voltage cable (100 metres), earth fault suppression coil and a block that simulates the fault. I want to simulate overcompensation. I have done this so far, but I am not satisfied with the results and I am not sure if the values are correct. Has anyone simulated the same thing before and can answer some questions about it or provide me with a file?

Many thanks

With kind regards

Rene

[Ayush Anand]

Hi Rene,

Could you share your code or explain your question in more detail so I can replicate it on my end?

[Rene Schwitte]

Hello @Ayush Anand,

Thank you very much for your answer. Unfortunately I don't have a Matlab code, but a simulation in Simulink. I will explain my idea briefly and upload my simulation program tonight.

Situation:

As I have often heard that earth faults on the undervoltage side of the transformer have caused enormous damage, I would like to simulate this situation. For this purpose, I would like to build a system consisting of a transformer and an earth fault suppression coil, which also extends the short outgoing line of the transformer. The transformer is to be fed from a high-voltage network, which I have represented as a slack. In this setup, I now want to simulate an earth fault and see why the large damage occurred. Overvoltage, transient range, tipping oscillation, etc. The only problem is that I am not sure whether I have calculated the values for the individual equipment correctly and whether I can trust my values from the scope. I will upload my simulation here tonight and would be happy if you take a look at it and give me your opinion. Regarding the values and the level of detail of the model

Simulation values:

Mains: 110kV

Transformer: 110/10 kV; 40 MVA; short-circuit peak 12.6%; short-circuit losses: 144478W; no-load losses: 14741W

Earth fault quenching coil: 90A

Short cable: 4*3*4*630 NA2XS2Y (0.1167 Ω/km; 0.33 mH/km; 0.64 μF/km 20m).

Voltage transformer: 10 000/100 V. Unfortunately, no idea how to do this.