DSS Load, UCMT_tab table, param kv

* bdgd-tools version: 1.0.0
* Python version: 3.9
* Operating System: Windows 10

### Description

As quoted by @anacmamede , in the mapping of the DSS element Load "if (phases=1 & conn=wye) kv=TEN_FORN/sqrt(3) else kv=TEN_FORN", this should be considered in the key
```
[" Load"]["calculated"]["kv"]
```

### What I Did

```
Nothing was implemented yet
```
