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TimeDomainPowerFlow Module

The TimeDomainPowerFlow module provides tools and functions for time-series power flow analysis in power systems, including dynamic dispatch, voltage profile analysis, and renewable integration.

Module Overview

module TimeDomainPowerFlow

    using Printf
    using SparseArrays
    using Plots
    using Statistics
    using DataFrames
    using XLSX
    using Dates

    # Module exports and includes
    # ...
end

Flow Chart

TimeDomainPowerFlow flow chart

Time Series Data Processing

Reading Load Data

read_load_data(file_path)

Read load time series data from an Excel file.

Arguments:

  • file_path: Path to the Excel file containing load data

Returns:

  • time_column: Vector containing time values from the first column
  • time_str_column: Vector containing time string representations from the second column
  • load_names: Vector of load names extracted from column headers
  • data: DataFrame containing the entire load dataset

This function reads load time series data from an Excel file into a DataFrame. It extracts the time values, time string representations, and the names of the loads from the column headers.

Simulation Functions

Run Single Day Simulation

run_single_day(old_jpc, opt, day_load_matrix, day_price_line, day_irradiance_line)

Run a day-ahead simulation for a hybrid AC-DC power system with renewable generation and energy storage.

Arguments:

  • old_jpc: Original power system data structure
  • opt: Power flow options
  • day_load_matrix: Matrix containing hourly load data (hour, busid, activepower, reactive_power)
  • day_price_line: Vector containing hourly electricity prices
  • day_irradiance_line: Matrix containing hourly solar irradiance data

Returns:

  • Simulation results including bus voltages, branch flows, and economic data

Run Dynamic Dispatch

run_dynamic_dispatch(new_jpc, Cld_ac, Cld_dc, loadAC_PD, loadAC_QD, loadDC_PD, genAC_PG,
                    Cgen_ac, Cconv_ac, Cconv_dc, η_rec, η_inv, Cpv_ac, Cpv_dc,
                    pv_ac_p_mw_ratio, pv_ac_p_mw, pv_max_p_mw, pv_max_p_mw_ratio,
                    Cstorage_ac, ess_initial_soc, ess_max_soc, ess_min_soc,
                    ess_charge_efficiency, ess_discharge_efficiency, ess_p_mw,
                    ess_e_mwh, ess_max_p_mw, ess_min_p_mw, time_step_h, time_periods,
                    price_line, irradiance_line, opt)

Performs dynamic dispatch optimization for a hybrid AC-DC power system with renewable generation and energy storage.

Arguments:

  • Power system parameters (jpc, loads, generators)
  • Converter parameters (efficiency, costs)
  • PV parameters (capacity, ratios)
  • Storage parameters (SOC limits, efficiency, capacity)
  • Time parameters and price/irradiance data
  • Power flow options

Returns:

  • Optimized dispatch results and power flow solutions

Visualization Functions

Plot Voltage Time Series

plot_voltage_time_series(results, bus_name, case, time_day, bus_type = "AC"; 
                         save_path = nothing, save_format = "pdf")

Plot voltage time series for a specified bus in a power system.

Arguments:

  • results: Simulation results containing bus voltage data
  • bus_name: Name of the bus to plot voltage for
  • case: Power system case data
  • time_day: Number of days in the simulation
  • bus_type: Type of bus to analyze ("AC" or "DC")
  • save_path: Optional path to save the plot
  • save_format: Format to save the plot

Plot Power Flow Violations

plot_flow_violations(results, case, time_day, flow_limit = 3.0, plot_type = "summary", 
                    flow_direction = "max"; save_path = nothing, save_format = "pdf")

Plot power flow violations in power system branches.

Arguments:

  • results: Simulation results containing branch flow data
  • case: Power system case data
  • time_day: Number of days in the simulation
  • flow_limit: Power flow limit in MW (default: 3.0)
  • plot_type: Type of plot to generate:
    • "summary": Overall statistics of violations
    • "worst": Shows the worst branches with violations
    • "all": Shows all branches with violations
  • flow_direction: How to evaluate flow violations:
    • "max": Maximum absolute value of flow in either direction
    • "both": Same as "max"
    • "forward": Only check flow from from-bus to to-bus
    • "reverse": Only check flow from to-bus to from-bus
  • save_path: Optional path to save the plot
  • save_format: Format to save the plot

Plot Losses Time Series

plot_losses_time_series(results, case, time_day, plot_type = "total", loss_type = "active"; 
                        save_path = nothing, save_format = "pdf")

Plot power system losses time series for AC and DC branches.

Arguments:

  • results: Simulation results containing branch flow data
  • case: Power system case data
  • time_day: Number of days in the simulation
  • plot_type: Type of plot to generate:
    • "total": Overall system losses
    • "branch": Individual branch losses for major branches
  • loss_type: Type of losses to display:
    • "active": Only active power losses (MW)
  • save_path: Optional path to save the plot
  • save_format: Format to save the plot

Plot Active Load Time Series

plot_PD_time_series(results, bus_name, case, time_day; 
                   save_path = nothing, save_format = "pdf")

Plot the time series of active load.

Arguments:

  • results: Result dataset
  • bus_name: Bus name
  • case: Power system case data
  • time_day: Number of days in the simulation
  • save_path: Optional path to save the plot
  • save_format: Format to save the plot

Record Voltage Violations

record_voltage_violation(results, bus_name, case, time_day, bus_type = "AC"; 
                        save_path = nothing, save_format = "pdf")

Analyze and visualize voltage violations for a specified bus in a power system.

Arguments:

  • results: Simulation results containing bus voltage data
  • bus_name: Name of the bus to analyze voltage violations for
  • case: Power system case data
  • time_day: Number of days in the simulation
  • bus_type: Type of bus to analyze:
    • "AC": AC bus
    • "DC": DC bus
  • save_path: Optional path to save the plot
  • save_format: Format to save the plot

Utility Functions

Renumber Hybrid System

renumber_hybrid_system(jpc)

Renumber buses and branches in a hybrid AC-DC power system to create a more organized numbering scheme.

Arguments:

  • jpc: A structure containing the hybrid power system data with fields:
    • busAC: Matrix of AC bus data
    • busDC: Matrix of DC bus data
    • branchAC: Matrix of AC branch data
    • branchDC: Matrix of DC branch data
    • convAC: Matrix of AC converter data
    • convDC: Matrix of DC converter data

Returns:

  • Updated jpc with renumbered components

Testing

The module includes a test script (test_time_domain_pf.jl) that demonstrates the use of the TimeDomainPowerFlow module for analyzing a power system over a time period. The script:

  1. Loads required packages
  2. Reads power system data
  3. Configures simulation parameters
  4. Runs time-domain power flow analysis
  5. Generates visualization of results
using Dates
using XLSX
using DataFrames
using Base.Filesystem
using HyDistFlow.TimeDomainPowerFlowlow

# Input Data
file_path = joinpath(pkgdir(HyDistFlow), "data", "test_case.xlsx")
load_path = joinpath(pkgdir(HyDistFlow), "data", "load.xlsx")  
price_path = joinpath(pkgdir(HyDistFlow), "data", "price.xlsx")  
irradiance_path = joinpath(pkgdir(HyDistFlow), "data", "irradiance.xlsx")  

# Process Data
case = load_julia_power_data(file_path)
time_column, time_str_column, load_names, data = read_load_data(load_path) 
time_column, time_str_column, price_profiles = read_price_data(price_path)  
time_column, time_str_column, irradiance_profiles = read_irradiance_data(irradiance_path) 

# Topology processing
results, new_case = topology_analysis(case, output_file="topology_results.xlsx")

# Clear existing storage data and add a new battery storage system
empty!(new_case.storageetap)
push!(new_case.storages, Storage(1, "Battery_ESS_1", 3, 0.75, 1.5, 0.3, 0.05, 0.95, 0.9, true, "lithium_ion", true))

# Set control mode for converters to Droop_Udc_Us (voltage droop control)
new_case.converters[3].control_mode = "Droop_Udc_Us"
new_case.converters[2].control_mode = "Droop_Udc_Us"
new_case.converters[1].control_mode = "Droop_Udc_Us"

opt = options() # The initial settings 
opt["PF"]["NR_ALG"] = "bicgstab";
opt["PF"]["ENFORCE_Q_LIMS"] = 0;
opt["PF"]["DC_PREPROCESS"] = 1;

# Run time-series power flow calculation and measure execution time
@time results = runtdpf(new_case, data, load_names, price_profiles, irradiance_profiles, opt)

# # Get voltage results for all nodes
plot_result = plot_voltage_time_series(results, "Bus_21", new_case, 366, "AC"; save_path="voltage_plot")