Battery and inverter safety with electric motors (elevator)

Just one more question guys: let's imagine I did not compensate reactive power by including capacitors. For the same load of the graph above (4.9 kVA, 1.6 kW, 4.6 kVar inductive) who would feed what? I mean, would the battery inverter (3.3 kW rated power) feed the 1.6 kW plus part of the reactive part (adding up a total of 3.3 kVA), thus leaving the remaining reactive load to be fed by the grid?

Or would the inverter feed 3.3 kVA but shaving the same proportion of active and reactive power, leaving some active and some reactive power to be fed by the grid?

Thanks in advance.

Thanks a lot Bill, I appreciate your contribution.

The diagram is just that: a simple diagram to show how the main components are placed. You are right, there is no main panel, protections, etc. but of course they need to be considered. However too much detail would have been distracting to the readers, in my opinion, and just wanted to ask about reactive power. 

In Spain, with current laws, there is no net metering or feed in tariff. You are paid by the PV production at the same rate as big utilities are (e.g. nuclear or coal power plants). In the case of installing batteries, they also require a third meter for loads. All this is very bizarre, I agree, and the laws and computations are thought by legislators that do not want renewables to flourish, because they have more interest in keeping fossil fuels alive. This is how it is right now in Spain, unfortunately, so I have to deal with it!

I have to do the numbers, like you say, with and without compensation of reactive power and see what's more favorable.

With compensation, I am somehow reluctant to use capacitors with contactors. Like you said, they need to be discharged, and this means they need at least from 1 minute to 5 minutes depending on the solution adopted. Am I right? This means no compensation during this time and therefore no compensation of reactive power of several elevator trips in between. In my opinion there is also the problem of the delta-star starting / stopping. In a normal elevator sequence, the motor starts (star), then runs (delta) and finally, when it arrives to destination, it goes back to star and finally the electro-magnetic brake forces the elevator to stop. Star-delta-Star means two times the contactors change current phase, something that shortens capacitor lifespan. That's why I said that the contactors should "enter" only when the motor is in delta configuration (elevator running). I see that this does not suppose any problem to you, but I believe an elevator with 200 trips per day, 73000 trips per year means that those contactors and capacitors will suffer quite a lot after a while. Very different is a motor in a factory that starts half a dozen times per day?

I have also checked solid-state contactors for the capacitors (with thyristors). Apparently they have zero crossing detectors that plug the capacitor when voltage crosses zero and they disconnect the capacitor when current crosses zero. I have to double check all this, but if this works as described, this means the capacitor is already discharged and ready for the next use within only ms. These devices are quite expensive though, and I don't have experience with them.

There is also the option of not compensating reactive power (hence my previous post). Here in Spain meters also average power in 15 minute slots. When you install a PV system, the utility takes advantage of the occasion and upgrades your meter. This means that your old analog meter (which only measures active power) is replaced by a digital one that also measures active and reactive energy consumed. This is, of course, not favorable for the client, because reactive power is penalized in Spain in a three-phase electric bill.

The inverters I plan to use are Fronius (for the PV array) and Sonnen (battery inverter). If you check the Fronius datasheet you can see that it is mentioned that the inverter can deliver any cos phi. I assume that this means it can adjust to any reactive load. 

Sonnen inverters do not mention this in their datasheet. I have tried contacting the manufacturer but they don't reply (not even to their distributors here in Spain, which I am also in contact with, and they are surprised of not getting an answer). I cannot assume that this battery cannot deliver reactive power, because the distributor (also PV installer) has confirmed that they have done one standalone (no grid) installation where the battery inverter was, effectively, feeding a load at cos = 0.46.

So this leaves the question in my last post still unanswered: I meant to query about the ratios of active and reactive power that would be split at a given moment by the battery inverter and the grid (I need this to figure out what the electric bill would be without compensation of reactive power):

If the load consumes: 4.9 kVA (1.6 kW + 4.6 kVar).

Then, what would the scenario be:

A)
The battery inverter (rated 3.3 kW) delivers 1.6 kW + 2.89 kVar = 3.3 kVA
The grid delivers 0 kW + 1.86 kVar = 1.86 kVar

or

B ) 

The battery inverter delivers 1.056 kW + 3.135 kVar = 3.3 kVA (these are load values multiplied by 3.3/4.9)
The grid delivers 0.544 kW + 1.615 kVar = 1.704 kVA 

I guess this is difficult to know, unless I find a way to test it...