Waalaikumussalam warahmatullahi wabarakaatuh.
Bismillahir rahmaanir rahim.
A woman will be catogorized as a mustahaadhah (one of a chronic vaginal disease) if she emits so much of discharge to such an extent that the entire solat time passes and there was not even enough time for her to perform a fardh solat without discharge.
When this happens, she will have to perform istinjaa', wear a new pad, perform wudhu' and immediately perform the solat without any delay besides due to necessity (eg. covering one's aurah, preparing the place of solat etc.).
In this case, any other factors that validate wudhu' (eg. passing of wind, urine, stool etc.) will nulify her solat besides discharge even if she experiences discharge while performing her solat. You may insert tissue slightly into the vagina to help absorb the discharge if too much is emitting.
Please refer to this link for more details: http://qa.muftisays.com?1753
And Allah knows best.