Enhanced backward/forward sweep based load flow approach for extended radial distribution system

A non-transitory computer-readable medium storing a program executable by a processor to perform a method of backward/forward sweep based power flow analysis, the method comprising:

• receiving data of a radial distribution network, the radial distribution network including nodes and branches that are sequentially numbered and belong to different layers, the data including information describing a topology of the radial distribution, impedance of each of the branches, and admittances of shunt elements associated with each of the branches or the nodes;
• performing a current iteration of the power flow analysis on the radial distribution network, including:
• performing a backward sweep to determine first branch currents of the radial distribution network based on the data and nodal voltages determined at a last iteration of the power flow analysis on the radial distribution network;
• performing a forward sweep to determine first nodal voltages of the radial distribution network based on the data and the first branch currents;
• determining second branch currents of the radial distribution network based on the data and the first nodal voltages, wherein the second branch current of the respective node is a sum of (i) a nodal injection current of the respective node that is updated based on the first nodal voltage of the respective node, and (ii) if available, the first branch currents of branches emanating from the respective node;
• and
• determining second nodal voltages of the radial distribution network based on the data and the second branch currents, wherein the second nodal voltage of the respective node is the first nodal voltage of an upper layer node neighboring the respective node minus a voltage drop caused by the second branch current from the upper layer node to the respective node;
• operating the radial distribution network at the second nodal voltages and the second branch currents when a maximum voltage or power difference at one of the nodes between the present iteration and a previous iteration among the nodes is less than a convergence threshold;
• and
• performing a next iteration of the power flow analysis on the radial distribution network according to the second nodal voltages when the maximum voltage or power difference exceeds the convergence threshold.

An apparatus of backward/forward sweep based power flow analysis, comprising circuitry configured to:

• receive data of a radial distribution network, the radial distribution network including nodes and branches that are sequentially numbered and belong to different layers, the data including information describing a topology of the radial distribution, impedance of each of the branches, and admittances of shunt elements associated with each of the branches or the nodes;
• perform a current iteration of the power flow analysis on the radial distribution network, including:
• perform a backward sweep to determine first branch currents of the radial distribution network based on the data and nodal voltages determined at a last iteration of the power flow analysis on the radial distribution network;
• perform a forward sweep to determine first nodal voltages of the radial distribution network based on the data and the first branch currents;
• determine second branch currents of the radial distribution network based on the data and the first nodal voltages, wherein the second branch current of the respective node is a sum of (i) a nodal injection current of the respective node that is updated based on the first nodal voltage of the respective node, and (ii) if available, the first branch currents of branches emanating from the respective node;
• and
• determine second nodal voltages of the radial distribution network based on the data and the second branch currents, wherein the second nodal voltage of the respective node is the first nodal voltage of an upper layer node neighboring the respective node minus a voltage drop caused by the second branch current from the upper layer node to the respective node;
• operate the radial distribution network at the second nodal voltages and the second branch currents when a maximum voltage or power difference at one of the nodes between the present iteration and a previous iteration among the nodes is less than a convergence threshold;
• and
• perform a next iteration of the power flow analysis on the radial distribution network according to the second nodal voltages when the maximum voltage or power difference exceeds the convergence threshold.