Distribution Optimal Power Flow Summary
Description
- The distroptimal power flow (OPF) analysis is an optimization problem that calculates the optimal controls in an electric power network to achieve a control objective function while enforcing system constraints. Due to the nonlinearity of the power flow equations, the OPF problem is typically a nonconvex formulation [1]. Certain assumptions can be made to simplify the OPF methods applied for problems in transmission systems. In distribution systems, however, many of these are no longer valid, since distribution systems generally have high R/X ratio, are unbalanced and have a more diverse device models and connections. Therefore, distribution optimal power flow (D-OPF) algorithms need to be developed to address the more complex OPF problem for multiphase distribution networks [2].
- The OPF problem is becoming increasingly important for distribution networks due to high deployment of distributed solar generation and controllable loads such as electric vehicles. Distributed solar generation and other distributed energy resources brought about several challenges, such as, challenges in forecasting actual load, coordination of local generation and dynamic loads. However, these new power system technologies also offer several opportunities, such as fast controls and controllable loads to compensate for their intermittent nature. To incorporate distributed generation and realize the potential of controllable loads, solving the D-OPF problem for distribution networks is inevitable.
- "Power system Volt/VAR optimization" refers to a specific type of D-OPF. Majority of the scenarios grouped under this use case are Volt/VAR. Distribution system Volt/VAR optimization varies both voltage levels and reactive power at active controls across a distribution system to enforce voltage levels across all nodes while varying controllable devices in the network. This objective is achieved through coordinated control of devices like voltage regulators and capacitor banks based on real-time data analysis.
- The figure below depicts the simulation capabilities that are offered to enable different what-if scenarios with D-OPF. The flow starts with solving a power flow case using OpenDSS to calculate the state variables for the network model that is picked by the user without using any controls. Record Federate saves those results on the user's workstation. Then, the user can either run one of the reference D-OPF algorithm(s) that OEDI SI provides or swap it with their own D-OPF algorithm. The users need to make sure that their algorithm follows the input and output requirements set up by OEDI SI for this use case. Finally, Recorder Federate prints out the results locally on the user's workstation.
- Please note that the workflow is defined by the OEDI SI administrators, and the users cannot arbitrarily modify it. The users can only manipulate the input data and its configuration parameters; and can swap their own D-OPF algorithm with the reference algorithm, only if they follow the I/O context and format.
Scenarios
Workflow
References
