When I increase the value of the “sampls” in Blender, these distortions occur. Why does this happen? And what are the responsible settings for that?
the first image with 200 samples
the image not good with 300 samples
Is this a default setting rendering? Or did you adjust other options?
I’ve experienced this before, but I don’t remember the solution.
The image of sample 200 also shows abnormalities in the same area. 
To solve this problem, you will need to understand these sampling settings and what they do.
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The noise treshold ends the rendering of each individual pixel when it falls below a certain amount of noise. If you were to set the max samples to 100000, the noise treshold would eventually be what ends the render, when every pixel has been completed. A smaller number=more quality.
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The max samples is a hard limit that will end the rendering if you reach it, no matter if there are still incomplete pixels. This number will affect mostly the more complicated areas of the image, because the simpler areas will be ended by the noise treshold much sooner.
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The min samples is a number of samples that will be rendered over the entire image before the treshold starts to be allowed to deactivate pixels. That number is useful to make sure every complex reflection and feature has been found before the treshold is used. If you set the number to 0, Cycles will pick a value for you, based on a fraction of the max samples (that value may or may not work depending on the scene, so you should choose one manually).
What is happening in your image: there are complex reflections in some parts of the image, which take multiple samples before they even start to show up in the noise. This causes a problem where the noise treshold mistakenly thinks some areas are clean and noiseless, because the noise hasn’t even appeared yet. Pixels get deactivated too soon and the complex reflections end up having gaps in them that denoise poorly.
The lower quality render doesn’t have as many patterns, because the problematic reflections haven’t even appeared yet, so the denoiser isn’t even affected by them.
The solution: more min samples. In interior scenes in general, you will need a high min samples count, especially if you have reflective materials or complex indirect lighting. I would recommend 128 min samples, 512 max samples and a noise treshold of 0.03 to start with.
Those kind of settings sadly are needed for an interior render as complex as this. If I need to render an animation in an interior scene, I usually bake the lighting to 32-bit textures on the walls and ceiling for this reason (it renders much faster and with less noise).
I will also tell you to verify if you have a few problematic features in your scene that can cause lots of noise:
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Lights shining through glass or glass windows (if you have them, use a glass material with no shadows).
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Does the window have a light portal? If not, you should add one, it will greatly reduce the noise from the sky.
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Point or mesh lights hidden deep into a hole. Those waste lots of rays and increase the noise of a scene. You seem to have one over the sink, if it is a mesh light, you might try replacing it with a well placed and adjusted area light (it is possible to make them visible to the camera if that’s important).
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This is exactly the kind of scene that might benefit from path guiding. I would try it, though it’s only a CPU feature for now, so I can’t guarantee it will be faster. Also, you might want to go to the “advanced” tab and set the “min light bounces” to something higher than 0, it will likely be less noisy and helps path guiding, especially in and interior scene with bright walls.