NMS has multiple tools for performing optimizations on the network involving distributed energy resources (DERs). These tools need the ability to know who is in control of a device at any given time and who has higher priority over that control. The Grid DERMS Management tool provides the centralized tool for managing these preferences.

Each DER has an entry in the grid_derms_management table. This table provides the structure for what algorithms these DERs are available for and what algorithm is currently using them (if any). Each DER can be individually enabled for one of the following sets of algorithms: DERMS, OPF, or VVO. These are broad categories of algorithms that fall into the following:

We track which algorithm any given DER is scheduled to be used for, tracking real and reactive power use separately. If a DER has no current schedule, it is free to be used. If a DER is schedule for one algorithm, we consult a globally set priority definition.

When a DER attempts to be used for a given algorithm, we consult the OPTIMIZATION_TYPE setting. This setting should have 3 different entries: DERMS OPTIMIZER, OPTIMAL POWER FLOW, and VOLTVAR OPTIMIZATION. For each entry we use the integer 1 and 2 entries to define the priority order for real and reactive power separately. By default, the preference is Algorithm (Real Pref, Reactive Pref): DERMS (1,3), OPF (2,2), VVO (3,1).

That is real power has the following preference: DERMS > OPF > VVO and reactive power has: VVO > OPF > DERMS.

A DER schedule can dynamically change let’s work through an example scenario. Assume we follow the default configuration and have a substation setup to run both CVR and NCA. CVR has run and used Xfmr 1, DER 1’s KW and KVAR, and DERs 2 KW to reduce demand. DER 1 will be scheduled for VVO for both real and reactive use. Now the time comes for periodic NCA to run. When NCA runs it looks at DER 1 and sees that it is a higher priority for the KW of both DER 1 and DER 2, and it sees that it is lower priority for DER 1’s KVAR so it can only use DER 2’s KVAR (if it wants to).

Assume NCA finishes and decides it only wants to use DER 1’s KW. It will take command of the real power for that DER marking its real power as scheduled for DERMS. When it steals the DER from CVR, CVR will be automatically rerun (same scenario as if topology changed). CVR will now begin its optimization by looking at what DERs are available. It will see that DER 1’s KW is unavailable, but its KVAR is still available. It will also see that DER 2’s KW and KVAR are both available. It can then perform its analysis using the Xfmr, DER 1’s KVAR, DER 2’s KW, and DER 2’s KVAR. It might come up with a solution that now uses that 2nd DERs KW, but it will most likely just use Xfmr 1, DER 1’s KVAR, and DERs 2 KW to reduce demand.

So in the end the schedule will have shifted:

DER X: Beginning (Kw Schedule, Kvar Schedule) -> End (Kw Schedule, Kvar Schedule)

DER 1: (VVO, VVO) -> (DERMS, VVO)

DER 2: (VVO, None) -> (VVO, None)

The interface for dynamically managing which DERs are used/available is found in Flex Operations under the Grid DERMS Management Tool. This tool provides a list of all DERs and several columns defining attributes of them:

Because of how many fields there are, we have three choices for which columns to show. By default, we “View Real”, meaning view the configurations for the real power. In the top right you can switch to View Reactive or View Both. The view real/reactive reuse the same names but within their context (Real or Reactive). For view both we show them both with a (P) or (Q) in the name. So we define for both Real(P) and Reactive(Q) the following:

Click on any DER and you can perform multiple actions (some of which allow multiple selections)