Energy management at the building’s level with the DCC product line by RVE

March 22 2022

In MURBs, the DCC solution allows for the supply of an EVSE (Electric Vehicle Supply Equipment) by intercepting the feeder upstream of a dwelling’s distribution panel. The DCC monitors the feeder current supplying the panel of a dwelling and temporarily disconnects the connected charger when the current intensity reaches a preset threshold.

Therefore, experts in electrical systems are allowed to exclude the charger’s load in the load calculation of the feeder supplying the dwelling electrical panel. However, since the RBQ interpretation published in March 2022, it is required to add the load at the level of the rest of the distribution upstream of the dwelling panel feeder with the application of the factors in Section 8-202 3) a).

In order to ensure that the distribution upstream of the dwelling panel feeder is not overloaded, several options are available:

1. Conduct an energy capacity study and, if necessary;

           a) adjust downward the maximum power of the charger (also called EVSE), and/or ;
           b) adjust downward the DCC charge controller landing threshold (also known as EVEMS single-tier).

2. Install a building-level energy management system (also known as an EVEMS multi-tiers)

 

Option 1

In order to identify the residual capacity of the distribution upstream of the dwelling panel feeder, an energy capacity study can be performed. The recommended methodology for performing a complete capacity study is to use actual consumption data from electricity meters depending on the transformers. This method provides a true picture of the previous year’s consumption peaks, in accordance with the Construction Code. To have access to this data, it is necessary to contact Hydro-Quebec and the representative in charge of the building in order to make a request for access to the data. Once this data is obtained, experts in electrical systems will then have the information necessary to identify the available capacity in the building and then apply the factors in Section 8-202(3)(a). If sufficient capacity is available, no further action is required. However, if the available capacity is not sufficient to power all the car chargers, experts in electrical systems may recommend one of the following actions:

Downwards adjustment of the maximum power of the charger

Most charger models, including the Flo G5 and Tesla’s Wall Connector, allow for limiting charger power. This can allow the installation to meet the distribution load calculation upstream of the dwelling panel, while still meeting the user’s needs.

Example, Flo G5 :

Switch position of the current limiter
FLO G5 power (A)
Circuit breaker (A)
*in the electrical panel
0 30 40
1 27 35
2 24 30
3 20 25
4 16 20
5 12 15
6 8 10
7 6 10
8 Not used Not used
9 Not used Not used

It is also possible to adjust the maximum power of the charger by changing the position of the “EVC” DIP switch in the DCC according to the following table:

Configuration of the “EVC” DIP switch in the DCC.

Downward adjustment of the DCC trip percentage

In order to shed the load earlier during a peak in energy use of the home, it is possible to change the percentage threshold of the maximum capacity of the home’s feeder that triggers a shedding of the charger. To do this, the position of the “TP” DIP switch in the DCC must be changed according to the following table:

Configuration of the ” TP ” DIP switch in the DCC. Note that it is set to 80% by default.

These operations will protect the distribution upstream of the dwelling panel feeder with a permanent or temporary configuration should the decision be made to install an EVEMS at a later date.

Option 2

In order to protect the distribution upstream of the dwelling panel, it is also possible to install a building-level energy management system (also called EVEMS multi-tiers). This type of system optimizes the distribution of the power available to all the chargers by monitoring the branch circuits, the feeders as well as the connection, to avoid exceeding the capacity of the installation, at all levels.

Here is how it is possible to integrate such a system with the DCC.

Spring 2022: The 3rd generation DCC

The 3rd generation of the DCC, available in the spring of 2022, features a “dry contact” control input that allows a building-level energy management system (EVEMS multi-tiers) to control the DCCs when the maximum capacity of the infrastructure upstream of the DCC is reached.

  • If the dry contact is open, the DCC temporarily disconnects the charger, even if there is sufficient capacity at the dwelling’s panel feeder.
  • The recommended building-level energy management system (EVEMS multi-tiers) is the LS-100 panel from Cristal Controls. This system allows up to 16 FIFO load shedding groups.

2024: The 4th generation DCC and DCC building-level energy management system

RVE is developing a complete multi-level EVEMS system. This system consists of a gateway with current readers and the 4th generation of the DCC .

This solution, via bidirectional connectivity between the gateway and the DCCs, enables more accurate and intelligent load shedding.

Intergenerational compatibility of DCC

  • The mechanical components (box, metal bridge) and the electrical elements (relays, fuses) remain unchanged between the generations of DCC.
    The current version of the DCC-BOX is compatible with all future generations of DCC-PCB
  • RVE will implement a return credit program for older generation PCBs on purchase of the 3rd and 4th generation of the PCBs.

Features of current and future DCC generations

DCC Gen 1 and 2
DCC Gen 3
DCC Gen 4
Availability
Current April 2022 2024
Compatibility with building-level energy management system (EVEMS multi-tiers)
None LS-100 DCC building-level energy management system 
Data connection between the energy management system and the DCC
N/A Unidirectional Bidirectional
Smart load shedding
No No Yes
Power modulation of compatible chargers
No No Yes
This summary of the new explanatory booklet of the Régie du bâtiment du Québec on Chapter V, Electricity, of the Construction Code includes information that is intended to present the new features of the RBQ’s explanatory booklet. It is not a legal or professional opinion.

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