Power Flow

PowerSystems.jl provides the capability to run a power flow with the intention of providing a valid initial AC operating point to the system.

The power flow tool is not meant for analytics where the principal goal is to determine if the system has settings that produce a feasible AC solution. This power flow routine does not check for reactive power limits or other limiting mechanisms in the grid, and can therefore be used to check for solver convergence - making no guarantees of the solution feasibility.

The power flow solver uses NLsolve.jl under the hood and takes any keyword argument accepted by NLsolve. The solver uses the current operating point in the buses to provide the initial guess.

Limitations: The PowerFlow solver doesn't support systems with HVDC lines or Phase Shifting transformers yet. The power flow solver can't handle systems with islands.

Check section Power Flow for detailed usage instructions

using PowerSystems
const PSY = PowerSystems

system_data = System(joinpath(DATA_DIR, "matpower/case14.m"))

System

Base Power: 100.0

Components

Num components: 73

TimeSeriesContainer

Components with time series data: 0

Total StaticTimeSeries: 0

Total Forecasts: 0

Resolution: 0 seconds

PowerSystems.jl has two modes of using the power flow solver.

1. Solving the power flow for the current operating point in the system. Takes the data in the buses, the active_power and reactive_power fields in the static injection devices. Returns a dictionary with results in a DataFrame that can be exported or manipulated as needed.

2. Solves the power flow and updated the devices in the system to the operating condition. This model will update the values of magnitudes and angles in the system's buses. It also updates the active and reactive power flows in the branches and devices connected to PV buses. It also updates the active and reactive power of the injection devices connected to the Slack bus, and updates only the reactive power of the injection devices connected to PV buses. If multiple devices are connected to the same bus, the power is divided proportional to the base power. This utility is useful to initialize systems before serializing or checking the addition of new devices is still AC feasible.

Solving the power flow with mode 1:

results = solve_powerflow(system_data)
results["bus_results"]

Solving the power flow with mode 2:

Before running the power flow command these are the values of the voltages:

for b in get_components(Bus, system_data)
    println("$(get_name(b)) - Magnitude $(get_magnitude(b)) - Angle (rad) $(get_angle(b))")
end

Bus 3     HV - Magnitude 1.01 - Angle (rad) -0.22200588085367873
Bus 11    LV - Magnitude 1.057 - Angle (rad) -0.2581341963699613
Bus 9     LV - Magnitude 1.056 - Angle (rad) -0.2607521902479528
Bus 1     HV - Magnitude 1.06 - Angle (rad) 0.0
Bus 13    LV - Magnitude 1.05 - Angle (rad) -0.2645919146023404
Bus 10    LV - Magnitude 1.051 - Angle (rad) -0.26354471705114374
Bus 7     ZV - Magnitude 1.062 - Angle (rad) -0.23335052099164186
Bus 8     TV - Magnitude 1.09 - Angle (rad) -0.2331759880664424
Bus 5     HV - Magnitude 1.02 - Angle (rad) -0.15323990832510212
Bus 14    LV - Magnitude 1.036 - Angle (rad) -0.27995081201989047
Bus 12    LV - Magnitude 1.055 - Angle (rad) -0.2630211182755455
Bus 6     LV - Magnitude 1.07 - Angle (rad) -0.24818581963359368
Bus 2     HV - Magnitude 1.045 - Angle (rad) -0.08691739674931762
Bus 4     HV - Magnitude 1.019 - Angle (rad) -0.18029251173101424

solve_powerflow! return true or false to signal the successful result of the power flow. This enables the integration of a power flow into functions and use the return as check. For instance, initializing dynamic simulations. Also, because solve_powerflow! uses NLsolve.jl all the parameters used for NLsolve are also available for solve_powerflow!

solve_powerflow!(system_data; finite_diff = true, method = :newton)

true

After running the power flow command this are the values of the voltages:

for b in get_components(Bus, system_data)
    println("$(get_name(b)) - Magnitude $(get_magnitude(b)) - Angle (rad) $(get_angle(b))")
end

Bus 3     HV - Magnitude 1.01 - Angle (rad) -0.2221206
Bus 11    LV - Magnitude 1.055954 - Angle (rad) -0.2582317
Bus 9     LV - Magnitude 1.0536844 - Angle (rad) -0.2605284
Bus 1     HV - Magnitude 1.06 - Angle (rad) 0.0
Bus 13    LV - Magnitude 1.0500508 - Angle (rad) -0.2647811
Bus 10    LV - Magnitude 1.0491216 - Angle (rad) -0.2633861
Bus 7     ZV - Magnitude 1.0603896 - Angle (rad) -0.2329706
Bus 8     TV - Magnitude 1.09 - Angle (rad) -0.2329706
Bus 5     HV - Magnitude 1.0192849 - Angle (rad) -0.1531107
Bus 14    LV - Magnitude 1.0340927 - Angle (rad) -0.2798801
Bus 12    LV - Magnitude 1.055018 - Angle (rad) -0.2634456
Bus 6     LV - Magnitude 1.07 - Angle (rad) -0.2485369
Bus 2     HV - Magnitude 1.045 - Angle (rad) -0.0869681
Bus 4     HV - Magnitude 1.0173242 - Angle (rad) -0.1798885