Reactive power interpretation

The question is about we have an unbalanced system under study and i found that power factor calculation does not obeys the well known geometrical relationship called power triangle nor the arithmetical relationship also.

However if I consider that reactive power is only an effect of the phase shift between the voltage and current the calculated power factor is almost the power factor measured.

So the well know arithmetical and geometrical equations do not describe energy flow between the supply and the load under unbalanced conditions.....this is my point of view.

From here my original question about the physical interpretation of reactive power...in other words: is reactive power a physical entity or is just an effect?

Another curious thing is that load under study are heating resistances and theory says that resistor have a unity power factor...however such resistors demands reactive power from the supply source, so cannot be considered as loads with unity power factor under unbalanced conditions but again if i consider the reactive power as an effect I can calculate the power factor almost matching the measured values.....!to calculate a power factor for a resistor!!, ...yes i know it sounds estrange....

In my opinion reactive power is just an effect and not a physical entity but i want to know other opinions and points of view.

My opinion is that reactive power only fiction which is made by engineers with purpose to be explained need for improvement of value of power factor... Reactive power is power which is a consequence of power factor which value is lower than 1. In cases when we are talking about consumers which is value of power factor lower than 1 (electrical machines), we need to improve value of power factor by using synchronous generator or capacitor bank.

So, we don't have need to use reactive power anywhere... We can't use reactive power for anything which isn't same case when we are talking about active power...
But, by other side, we have a lot of reactive power losses in power system. For example, we have reactive power losses in transmission lines and distribution lines as a consequence of supplying of mentioned lines by voltage. In these situations, transmission lines and distribution lines are behaving like capacitors in relation to the earth. Other example, we have reactive power losses in electrical machines which are a consequence of dissipation of magnetic flux and magnetising of ferromagnetic core.

Also, if we have a very high voltage drops in our power system, we know that we need to improve value of power factor at the places which are the most critical. We can improve value of power factor at the places which are the most critical by using synchronous generator or capacitor bank. On this way, we will reduce reactive power losses at the places where we need to install equipment for improving of value of power factor, we will reduce voltage drops in our transmission lines and distribution lines and we will unload our transmission lines and distribution lines what is the most important thing in aspect of warming of mentioned lines and occupancy of capacity (size) of mentioned lines...
So, my opinion is the significance of reactive power very important and very complicated for understanding, because reactive power depends from a lot of things and conditions.