Continued work on feature docs

docs/features/power-tracking.md

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 # Power Tracking
 
-TODO
+As part of its DCIM feature set, NetBox supports modeling facility power as discrete power panels and feeds. These are most commonly used to document power distribution within a data center, but can serve more traditional environments as well.
+
+![Power distribution model](../media/power_distribution.png)
+
+## Power Panels
+
+A power panel is the furthest upstream power element modeled in NetBox. It typically represents a power distribution panel (or breaker panel) where facility power is split into multiple discrete circuits, which are modeled as feeds.
+
+Each power panel is associated with a site, and may optionally be associated with a particular location within that site. There is no limit to how many power feeds a single panel can supply, however both of these object types should map to real-world objects.
+
+## Power Feeds
+
+A power feed represents a discrete power circuit originating from an upstream power panel. Each power feed can be assigned a name, operational status, and various electrical characteristics such as supply (AC or DC), voltage, amperage, and so on.
+
+A device power port can be connected to a power feed via a cable. Only one port can be connected to a feed: Where multiple devices draw power from the same feed, a power distribution unit (PDU) must be modeled as an individual device mapping a power port to multiple power outlets to which the downstream devices can connect (as in the example above).
+
+!!! tip "Primary and Redundant Power"
+    Each power feed in NetBox is assigned a type: primary or redundant. This allows easily modeling redundant power distribution topologies. In scenarios involving only a single, non-redundant power supply, mark all power feeds as primary.