$9\mathrm{.}21$

Consider a three$-$phase impedance load with the following phase impedance matrix:

$$

P

$=$

$[$

$($

$5$

$+$

$$

$10$

$)$

$0$

$0$

$0$

$($

$5$

$+$

$$

$10$

$)$

$0$

$0$

$0$

$($

$5$

$+$

$$

$10$

$)$

$]$

$$

Determine the sequence impedance matrix

$$

S

for this load. Is the load symmetrical?