| Energy Management System (EMS) |
Term used in NEC to refer to the software controls of production sources (Solar
& Battery) to maintain system limits |
| Power Control System (PCS) |
Term used by UL 1741, NEC, and Tesla to refer to the software controls of
production sources (Solar & Battery) to maintain system limits. PCS is a type of
Energy Management System (EMS) |
| Powerwall |
Powerwall is a rechargeable home battery, also called a battery energy storage
system (BESS). Powerwall has an integrated energy meter and performs its own battery
metering |
| Qualified Personnel |
A Tesla installer or Certified Installer who has the skills and knowledge related
to installation and operation of electrical equipment to recognize and avoid the
hazards involved |
| Site Limit |
Prevents excess Import and/or Export through the site meter from/to the utility
connection |
| Conductor Limit |
Prevents excess current through specific monitored and controlled
conductors |
| Panel Limit |
Prevents excess current experienced by a virtual panel, fed by a sum of site,
solar, and batteries |
| Power / Current Limit (Powerwall 3 Only) |
Configures the maximum power / current output for Powerwall 3 |
| Grid |
Measured by one or more physical site meters to measure the full current flowing
into the virtual panel from the grid |
| Uncontrolled Sources |
Any equipment not connected over direct communication, including standalone solar
inverters or similar sources to the virtual panel |
| Controlled Sources |
Any equipment connected over direct communication, including Tesla Powerwall 2,
Tesla Powerwall+, and/or Tesla Powerwall 3 in any quantity and combination (e.g. one Powerwall+ and two Powerwall 2) that can
be current limited |
| Virtual Panel |
May include several panels and conductors, and is considered as one single panel
with respect to the Panel Limit feature. As there may be more than one physical panel
and conductors included, the Panel Limit is set to the rating of the smallest busbar
within the “Virtual Panel” |
| Energy Meter |
Measures voltage and current to calculate net power flow. Energy meters can be of
type Site, Solar, Conductor, or Load. See the Residential Energy Metering Guide for more
information about meter types |
| Current Transformer (CT) |
Installed around conductors to monitor the current flowing through them. CTs are
connected to an energy meter, which uses the current measurement to calculate how much
power is being produced or consumed |
| Site Controller |
Tesla’s Site Controller is the computer that coordinates site functions like
charging, discharging, self-consumption, power control, etc. All Powerwall systems
have a Site Controller |
| Meter X |
Built-in meter in the Backup Gateway 2. Its CTs cannot be relocated |
| Meter Y |
Built-in meter in the Backup Gateway 2 with three CT terminals. Tesla CTs are
installed and connected to Meter Y |
| Meter Z |
Built-in meter in Backup Switch and Gateway 3. Its CTs cannot be relocated |
| Remote Energy Meter |
Third party meters that can be installed and paired with the Site Controller for
additional metering capability. Neurio W1 and W2 meters are both supported Remote
Energy Meters |