What is the direction of negative reactive power
It is a common misunderstanding that a voltage source must also be a power source. That's not true, an ideal voltage source merely constrains the voltage between two points in a circuit. Current may flow in either direction through the source, causing it to consume power or provide power. Think about a rechargeable battery, for example. If you have some kind of standby power supply, the battery will be charging (consuming power) part of the time and supply power part of the time.