1.3.1.3.9 TOU and Energy Registering

TOU stands for “Time of Use”, and it is a relevant concept in the smart energy meters. The energy consumption is assigned and grouped into different time zones. These time zones could correspond to intervals of the day, to special days (for example, weekends) or periods (for example, summer). Each time zone has an associated tariff for billing purposes.

The application provides a simple implementation that can be easily modified. Specifically, the day hours are divided into several time zones (maximum 8). Each time zone is associated to an identifier (maximum 4) and corresponding to a tariff. As an example, suppose three tariffs are defined:

Id 1: Peak tariff, corresponding to peak times and having the higher prices. It is the red zone of the graph, from 9:00 to 16:00
Id 2: Medium tariff, related with intermediate prices. It is the yellow zone of the graph, from 5:00 to 9:00 and from 16:00 to 20:00
Id 3: Valley tariff, with lower prices. It is the green zone of the graph, from 20:00 to 5:00

So, there are 3 tariffs and 4 time zones. The “TOUW” command is used to define the time zones and to assign the tariff to each time zone. The command to be sent is: “TOUW[PIC](05:00 02 09:00 01 16:00 02 20:00 03)“

The metrology library is continuously measuring energy, and the application accumulates the energy in the proper tariff according to the real time clock information. This way, all the energy registered in the red area is accumulated in tariff 1 (T1), the energy in the yellow areas in tariff 2 (T2), and the energy in the green areas in tariff 3 (T3).

Here is a simple example:

Write the new TOU table

TOUW[PIC](05:00 02 09:00 01 16:00 02 20:00 03)
Set TOU is Ok !·

Erase the energy records in the meter

ENC[PIC]
Clear Energy is ok !
ENR[0]
Last 0 Month Energy is :
TT=0.0kWh T1=0.0kWh T2=0.0kWh T3=0.0kWh T4=0.0kWh

Read the RTC

RTCR
Present RTC is :
20-07-28 2 04:58:04

The present time corresponds to tariff 3 (green area), but soon the system will enter in tariff 2 (yellow area). Now, the user energizes the meter test bench to force the board to register energy. Then, the user reads the energy register and the RTC several times to see how the energy measured is being registered and assigned to the proper tariff.
```
ENR[0]
Last 0 Month Energy is :
TT=0.01kWh T1=0.0kWh T2=0.0kWh T3=0.01kWh T4=0.0kWh
RTCR
Present RTC is :
20-07-28 2 04:58:41
ENR[0]
Last 0 Month Energy is :
TT=0.04kWh T1=0.0kWh T2=0.0kWh T3=0.04kWh T4=0.0kWh
RTCR
Present RTC is :
20-07-28 2 04:59:13
ENR[0]
Last 0 Month Energy is :
TT=0.07kWh T1=0.0kWh T2=0.0kWh T3=0.07kWh T4=0.0kWh
RTCR
Present RTC is :
20-07-28 2 04:59:47
```
The application is assigning all the energy measured to tariff 3 (T3). The other tariffs remain at 0 KWh.

Now, the time zone will change to the yellow area. The user continues reading:

ENR[0]
Last 0 Month Energy is :
TT=0.09kWh T1=0.0kWh T2=0.01kWh T3=0.08kWh T4=0.0kWh
RTCR
Present RTC is :
20-07-28 2 05:00:22
ENR[0]
Last 0 Month Energy is :
TT=0.11kWh T1=0.0kWh T2=0.03kWh T3=0.08kWh T4=0.0kWh
RTCR
Present RTC is :
20-07-28 2 05:00:42

The system changed to the yellow area; therefore, the energy is now assigned to tariff 2 (T2). “TT” registers the total energy.