Introduction

The method presented in the code enable accurate calculation of power flow contributions, both active and reactive, from any power source to any network element and load. Additionally, it facilitates the determination of losses in network elements associated with these contributions. Consequently, the method provides the capability to calculate network power losses associated to every source-to-load pair, as well as power losses in the network attributed to any specific load or any source.

Install

In the code we perform power flow computation using Matpower, which we also use as a source of input data for several test cases. We run Matpower under GNU Octave, therefore both GNU Octave and Matpower have to be installed. To test the functionality, open up a terminal or a command prompt, navigate to the directory with the code and run the following command

octave --eval "my_runpf('case1')"

Python requirements are installed with the following command

pip install -r requirements.txt

Run

The file case1.m contains the input data, in Matpower format, for the simple power system depicted in Fig. 1. In order to calculate the power flow contributions run the following command

python power_components.py -c case1

The components of active power losses (kW) in each branch can be obtained with the following command, which generates table 4

python losses_components.py -c case1

Fig. 1. Single-line diagram of the simple system

In this system, each line is represented by a π-equivalent circuit with total series impedance (12+j40.9) Ω and a total shunt admittance of j277 μS. The generator at bus 2 produces 20 MW of active power and consumes 5 Mvar of reactive power. Loads at bus 2 and 3 are equal and their power consumption is (50 + j20) MVA. Total line losses in the network amount to (4.727+j6.743) MVA and the total generator power at bus 1 is (84.727+j51.743) MVA.

Table 1 presents the results of total active and reactive power flows at both line buses.

The reason we selected this simple system is to demonstrate, within a reasonably small space, all the results that can be obtained using the proposed method. These results are presented in Tables 2-5.

Table 1. Total Power Flows in Lines (MVA)

Line	Beginning	End
1-2	38.608 + j26.148	36.545 + j22.378
1-3	46.119 + j25.595	43.506 + j19.945
2-3	6.545 - j2.622	6.494 + j0.055

Table 2. Origin of Active and Reactive Power Flow Contributions in Loads (MVA)

Load	Generator 1	Generator 2	Line 1-2	Line 1-3	Line 2-3
Load at 2	32.315 + j15.662	17.685	j2.241		j2.098
Load at 3	47.703 + j17.286	2.297		j2.659	j0.055
Gen. at 2	j3.9154	20	j0.5602		j0.5244

Table 3. Origin of Active and Reactive Power Flow Contributions in Lines (MVA)

Line and bus	Generator 1	Generator 2	Line 1-2	Line 1-3	Line 2-3
1-2 at 1	38.608 + j26.148
1-2 at 2	36.545 + j19.577		j2.801
1-3 at 1	46.119 + j25.595
1-3 at 3	43.506 + j17.286			j2.659
2-3 at 2	4.23	2.315			j2.622
2-3 at 3	4.197	2.297			j0.055

Table 4. Participation of Sources in Line Power Losses (MVA)

Line	Gen. 1	Gen. 2	Line 1-2	Line 1-3	Line 2-3	Total
1-2	2.063 + j6.571		-j2.801			2.063 + j3.770
1-3	2.613 + j8.309			-j2.659		2.613 + j5.650
2-3	0.033	0.018			-j2.677	0.051 - j2.677

Table 5. Source to Load Pairs Power Losses (MVA)

Source to load pair	Line 1-2	Line 1-3	Line 2-3
Gen. 1 to load 2	1.824 + j5.257
Gen. 1 to load 3	0.239	2.613 + j8.309	0.033
Gen. 1 to generator 2	j1.314
Gen. 2 to load 3			0.018
Line 1-2 to load 2	-j2.241
Line 1-2 to generator 2	-j0.560
Line 1-3 to load 3		-j2.659
Line 2-3 to load 2			-j2.0973
Line 2-3 to load 3			-j0.0550
Line 2-3 to generator 2			-j0.5243
Total line power losses	2.063 + j3.770	2.613 + j5.650	0.051 - j2.677

Results

All results are given in results. For the case1 the active power flow components are given in the file case1-apfc.csv, while the reactive power flow components are in case1-rpfc.csv. In the file case1.log the details of the calculations are given. Similar naming scheme is used for all other cases.