Isolation circuit between 1000V AC to having information signal and signal detector

Hi guys,

I have a setup in which 1000v 50Hz sinusoidal waveform have information signal of 1kHz riding on the 50Hz sinewave. voltage level of this 1KHz signal is 8volts AC.

At this moment I am in simulation phase of project so no hazard of High Voltage (HV).

The scenerio is that HV is going to be transfered from secondary winding of a step up transformer to the 3-phase motor and a 1kHz signal is being inserted at y-point of 3phase motor. This signal need to be detected on a phase line near secondary winding of the transformer. or at the y-point of the secondary of transformer.

Mean to say I directly need to tap 1KV from the phase line and to detect the signal from this line I need to design a detection circuit.

Now I need your help to design an isolation circuit which can protect signal detection circuit to 1kv line. and this isolator should have a kind of voltage divider circuit who can reduce the 1kv 50 Hz signal to 10VAC mean 100 times lower, but the amplitude of information signal (8vAC 1kHz) should remained significant.

Waiting for your valueable suggestions.

Couple the signal with a high voltage capacitor to a 2nd order, 1kHz passive filter. That will give a 52 dB rolloff (1/400) of the 50Hz signal and rolloff the 1kHz signal only 3dB (0.7). A higher order filter will roll off the 50Hz even more with respect to the 1kHz signal.

Here is a germ of an idea. Use a transformer (wound on a ferrite pot core or toroid). Series-Resonate the primary at 1kHz. With ideal components, the frequency domain sim shows -93db down at 50Hz compared to 1kHz. The time-domain plot is shown in the second attachment. Compare the amplitude of the two waveforms.