Power injection vector in DC load flow

[vikram reddy]

Hi,

I am working on a 20000 bus system and running a DC load flow. Now, the
power injection vector computed as

  Pbus = real(makeSbus(baseMVA, bus, gen)) - Pbusinj - bus(:, GS) / baseMVA;

In general, the total of the power injection vector should be zero implying
generation=load+losses. MATPOWER does not do the checking if the total of
injection vector is zero.

1. Why does MATPOWER not check if the total of injection vector goes to
zero? Is it not important?
2.  What happens if the injection vector is not zero and running the DC
load flow? I assume the voltage angles thus obtained will have an error.
3. Assuming losses is the total sum of Pbus vector, how should the losses
be distributed?

Thanks,
Vikram