Snapback after a DR Event
New GRIDlink feature helps reduce the effect of Snapback after a DR Event
Studies have shown that after considering the snapback effect, demand response resulted in overall energy savings but can this be improved?
DR Events are basically binary control (ON-OFF). The MODERATE or HIGH signal choice does give the Utility some granularity to attain the curtailment necessary but what is the effect at the Commercial-Industrial customer level when equipment begins to rebound back to normal operation?
Some VENs utilize the OpenADR ramp settings to allow the Output to start before the Event start time and end minutes after the Event end time. The fundamental problem is still the single binary output. There is no way to divide the load into individual resources without expensive re-programming of the BMS/EMS much less the rotating equipment.
The latest Control Logic ver. 6000.22 (released June 20, 2021) offers:
- 4 additional binary outputs that follow the Moderate or High Signals
- Individually configurable Start and End times from minutes to several hours.
Available on 113 & 135 Series
Accessible via onboard relays, Modbus or BACnet registers
Upgrade existing GRIDlinks via GRIDview.
Results will depend on the type of equipment and demand profile.
fig. 2 illustrates how by using the Pending Relay to Pre-Empt the Event and consume energy and then stagger the recovery over multiple loads can smooth the snapback.
This is achieved by simple configuration without any programming required.