The following problems are associated with reactive power over a cable :
The cables for their operations require high charging current and reactive power. This reactive power is fed to the system and is capacitive.
It may lead to risk of sending end voltage of the cable at lightly loaded condition
Generation of capacitive reactive power, may transfer the stability consideration of larger generators. Also switching of cable capacitors current may cause rise in over voltage.
Cable gets heated up due to the law of charging current and consequently its load current capability is reduced.
The absorption of reactive power is very essential in keeping the voltage of the cable or conductor stable.
Hence it should be ideally zero.