Depth-first search algorithm for BusBarSection IDs #293

ghazwarhili · 2025-09-29T14:26:35Z

Overview:
Nodes represent connection points
Switches (breakers, disconnectors) connect nodes
=> The goal is to use these informations to find which busbar a terminal is connected to

Algorithm Steps:
The search starts from a terminal's node and explores the network topology
The algorithm uses a queue to explore nodes level by level (by depth)
Finds the shortest path to each busbar
The algorithm applies a priority-based selection to choose the best busbar:
Priority 1: Direct connection (no switch in the path)
Priority 2: Connection through CLOSED switches
Priority 3: Connection through OPEN switches

=> The algorithm respects the real state of switches, prioritizing closed (active) connections over open (inactive) ones

if we consider the example of voltage level MUR P6 and we will search for the busbar section linked to MUR Y632

=== Starting busbar section search ===
Starting node: 7

--- Starting traversal ---

Iteration 1: Processing node 7 (depth: 0)
-> Marked as visited
-> Not a busbar, exploring adjacent nodes...
-> Adding node 14 to queue via switch MUR P6_MUR 6TR632 DJ_OC (BREAKER, CLOSED)

Iteration 2: Processing node 14 (depth: 1)
-> Marked as visited
-> Not a busbar, exploring adjacent nodes...
-> Adding node 0 to queue via switch MUR P6_MUR 6TR632 SA.1_OC (DISCONNECTOR, CLOSED)
-> Adding node 1 to queue via switch MUR P6_MUR 6TR632 SA.2_OC (DISCONNECTOR, OPEN)

Iteration 3: Processing node 0 (depth: 2)
-> Marked as visited
-> BUSBAR FOUND: MUR P6_1 (depth: 2, last switch: MUR P6_MUR 6TR632 SA.1_OC - CLOSED)

Iteration 4: Processing node 1 (depth: 2)
-> Marked as visited
-> BUSBAR FOUND: MUR P6_2 (depth: 2, last switch: MUR P6_MUR 6TR632 SA.2_OC - OPEN)

--- BFS traversal completed ---
Total nodes visited: 4
Total busbars found: 4
Found 4 busbar section(s), selecting best one...

--- Selecting best busbar from 4 candidates ---
Found 2 busbar(s) through closed switch
Selected: MUR P6_1 (depth: 2, last switch: MUR P6_MUR 6TR632 SA.1_OC - CLOSED)
Final result: MUR P6_1
=== Search completed ===

EtienneLt · 2025-09-30T14:12:18Z

Test OK on several voltage levels

etiennehomer · 2025-09-30T11:19:38Z

...in/java/org/gridsuite/network/map/dto/definition/extension/BusbarSectionFinderTraverser.java

+public final class BusbarSectionFinderTraverser {
+
+    /**
+     * Private constructor to prevent instantiation of this utility class.


comment to remove

etiennehomer · 2025-09-30T11:26:46Z

...in/java/org/gridsuite/network/map/dto/definition/extension/BusbarSectionFinderTraverser.java

+import java.util.*;

 /**
 * @author Slimane Amar <slimane.amar at rte-france.com>


etiennehomer · 2025-09-30T11:39:29Z

...in/java/org/gridsuite/network/map/dto/definition/extension/BusbarSectionFinderTraverser.java

+     * @param terminal the starting terminal
+     * @return the busbar ID or null if none found
+     */
+    public static String findBusbarSectionId(Terminal terminal) {


Move the records and this method just under the constructor

etiennehomer · 2025-09-30T11:40:09Z

...in/java/org/gridsuite/network/map/dto/definition/extension/BusbarSectionFinderTraverser.java

+     * @param terminal the starting terminal
+     * @return the best busbar result according to selection criteria, or null if none found
+     */
+    public static BusbarSectionResult findBestBusbar(Terminal terminal) {


Should return the busbar section id

Actually, you can remove findBusbarSectionId() and name this method findBusbarSectionId()

renamed to getBusbarSectionResult

I prefer not remove findBusbarSectionId, renamed to getBusbarSectionResult

etiennehomer · 2025-09-30T13:25:53Z

...in/java/org/gridsuite/network/map/dto/definition/extension/BusbarSectionFinderTraverser.java

+        }

-    private final boolean onlyConnectedBbs;
+        // Fallback: select first busbar


etiennehomer · 2025-09-30T13:27:14Z

...in/java/org/gridsuite/network/map/dto/definition/extension/BusbarSectionFinderTraverser.java

-    public String getFirstTraversedBbsId() {
-        return firstTraversedBbsId;
+    /**
+     * Internal record to track the path during graph traversal.


comments on records to remove ?

etiennehomer · 2025-09-30T13:45:48Z

...in/java/org/gridsuite/network/map/dto/definition/extension/BusbarSectionFinderTraverser.java

+    /**
+     * Record containing the result of a busbar search with selection metadata.
+     */
+    public record BusbarSectionResult(String busbarSectionId, int depth, int switchesBeforeLast, SwitchInfo lastSwitch) { }


What's the difference between depth and switchesBeforeLast ? It is redondant nope ?

Depth is not the same as switchesBeforeLast (busbarSectionId)
but switchesBeforeLast to be removed

etiennehomer · 2025-09-30T13:49:57Z

...in/java/org/gridsuite/network/map/dto/definition/extension/BusbarSectionFinderTraverser.java

+     * Selects the best busbar from a list of candidates using a priority-based approach:
+     * Priority 1: Busbar with closed last switch (minimum depth, then minimum switches before last)
+     * Priority 2: Busbar with open last switch (minimum depth, then minimum switches before last)
+     * Priority 3: Busbar without switch (direct connection, minimum depth)


Why this one is the least prioritized strategy ?

Should be the first one ?

etiennehomer · 2025-09-30T15:18:08Z

...in/java/org/gridsuite/network/map/dto/definition/extension/BusbarSectionFinderTraverser.java

+    /**
+     * Record containing information about a switch in the topology.
+     */
+    public record SwitchInfo(String id, SwitchKind kind, boolean isOpen, int node1, int node2) { }


int node1, int node2 are not used

I had used them for debugging purposes, but now we don't need them anymore
removed

etiennehomer · 2025-09-30T15:36:25Z

...in/java/org/gridsuite/network/map/dto/definition/extension/BusbarSectionFinderTraverser.java

+        return !visited.contains(node);
+    }
+
+    private static Optional<BusbarSectionResult> tryCreateBusbarResult(VoltageLevel.NodeBreakerView view, NodePath currentNodePath) {


Suggested change

private static Optional<BusbarSectionResult> tryCreateBusbarResult(VoltageLevel.NodeBreakerView view, NodePath currentNodePath) {

private static Optional<BusbarSectionResult> getDirectlyConnectedBusbarSection(VoltageLevel.NodeBreakerView view, NodePath currentNodePath) {

Something like this ? Here, we check if a busbar section is directly connected to the node and return it if yes

something better than getDirectlyConnectedBusbarSection() to be found

findBusbarSectionAtNode maybe ?

etiennehomer · 2025-09-30T15:42:51Z

...in/java/org/gridsuite/network/map/dto/definition/extension/BusbarSectionFinderTraverser.java

+        return results;
+    }
+
+    private static boolean hasNotBeenVisited(int node, Set<Integer> visited) {


Suggested change

private static boolean hasNotBeenVisited(int node, Set<Integer> visited) {

private static boolean hasBeenVisited(int node, Set<Integer> visited) {

etiennehomer · 2025-09-30T15:43:04Z

...in/java/org/gridsuite/network/map/dto/definition/extension/BusbarSectionFinderTraverser.java

+    }
+
+    private static boolean hasNotBeenVisited(int node, Set<Integer> visited) {
+        return !visited.contains(node);


Suggested change

return !visited.contains(node);

return visited.contains(node);

etiennehomer · 2025-10-01T07:20:31Z

...in/java/org/gridsuite/network/map/dto/definition/extension/BusbarSectionFinderTraverser.java

+    private static List<BusbarSectionResult> searchAllBusbars(VoltageLevel.NodeBreakerView view, int startNode) {
+        List<BusbarSectionResult> results = new ArrayList<>();
+        Set<Integer> visited = new HashSet<>();
+        Queue<NodePath> queue = new LinkedList<>();


Suggested change

Queue<NodePath> queue = new LinkedList<>();

Queue<NodePath> pathsToVisit = new LinkedList<>();

nodePathsToVisit maybe ?

etiennehomer · 2025-10-01T07:44:04Z

...in/java/org/gridsuite/network/map/dto/definition/extension/BusbarSectionFinderTraverser.java

+        return Optional.empty();
+    }
+
+    private static void exploreAdjacentNodes(VoltageLevel.NodeBreakerView view, NodePath currentNodePath, Set<Integer> visited, Queue<NodePath> queue) {


Suggested change

private static void exploreAdjacentNodes(VoltageLevel.NodeBreakerView view, NodePath currentNodePath, Set<Integer> visited, Queue<NodePath> queue) {

private static void exploreAdjacentNodes(VoltageLevel.NodeBreakerView view, NodePath currentNodePath, Set<Integer> visited, Queue<NodePath> pathsToVisit) {

etiennehomer · 2025-10-01T07:53:33Z

...in/java/org/gridsuite/network/map/dto/definition/extension/BusbarSectionFinderTraverser.java

+    }

-    private final boolean onlyConnectedBbs;
+    private record NodePath(int node, List<SwitchInfo> pathSwitches, SwitchInfo lastSwitch) { }


Suggested change

private record NodePath(int node, List<SwitchInfo> pathSwitches, SwitchInfo lastSwitch) { }

private record Path(int startNode, List<SwitchInfo> traversedSwitches, SwitchInfo lastSwitch) { }

Something like this ?

The term 'Path' is a generic name
it is ok for startNode and traversedSwitches

FranckLecuyer

Tests:
This does not return the right busbar section in some cases for voltage levels with 'pontages' ...

etiennehomer · 2025-10-01T08:01:53Z

...in/java/org/gridsuite/network/map/dto/definition/extension/BusbarSectionFinderTraverser.java

+    private record NodePath(int node, List<SwitchInfo> pathSwitches, SwitchInfo lastSwitch) { }

-    private String firstTraversedBbsId;
+    public record SwitchInfo(String id, SwitchKind kind, boolean isOpen) { }


SwitchKind kind is not used

I used it at the beginning for logging and debugging purposes
to be removed

etiennehomer · 2025-10-01T08:05:35Z

...in/java/org/gridsuite/network/map/dto/definition/extension/BusbarSectionFinderTraverser.java

+        if (!withOpenSwitch.isEmpty()) {
+            return withOpenSwitch.stream().min(Comparator.comparingInt(BusbarSectionResult::depth)).orElse(null);
+        }
+        return results.getFirst();


can be empty

This case is handled by returning result.busbarSectionId() when result is not null, and otherwise the Id of the first busbar section in the terminal’s voltage level

etiennehomer · 2025-10-01T09:23:58Z

...in/java/org/gridsuite/network/map/dto/definition/extension/BusbarSectionFinderTraverser.java

+    }
+
+    private static void exploreAdjacentNodes(VoltageLevel.NodeBreakerView view, NodePath currentNodePath, Set<Integer> visited, Queue<NodePath> queue) {
+        view.getSwitchStream().forEach(sw -> {


This is not efficient. Maybe we can do something better

ghazwarhili · 2025-10-01T11:06:30Z

#293 (review)
In case of a bypass (e.g., a bridging situation where multiple busbars are found at the same depth) => we resolve the conflict by comparing busbarIndex and sectionIndex, and selecting the minimum value.

Iteration 7: Processing node 2 (depth: 3)
-> Marked as visited
-> BUSBAR FOUND: ALBERP6_2.1 (depth: 3, last switch: ALBERP6_ALBER6VEN.P.1 SA.2_OC - CLOSED)

Iteration 8: Processing node 0 (depth: 3)
-> Marked as visited
-> BUSBAR FOUND: ALBERP6_1.1 (depth: 3, last switch: ALBERP6_ALBER6VEN.P.1 SA.1_OC - CLOSED)

=> return ALBERP6_1.1

sonarqubecloud · 2025-10-01T13:15:15Z

Quality Gate passed

Issues
1 New issue
0 Accepted issues

Measures
0 Security Hotspots
89.7% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

ghazwarhili added 12 commits September 15, 2025 13:16

enhance BusbarSectionFinderTraverser to handle all cases

c112b6a

add TU for fork topo

bd1c1c5

enhance coverage code

dab0cf8

Merge branch 'main' into fix-busbar-section-finder-traverser

8ea7a25

enhance TU

78f18fd

breadth-first busbasrsection id search algorithm

efc0ece

add TU

ca84d42

resolving conflicts

8ba0040

unused import

b03d915

fix sonar issues

a1482d3

enhance TU to add bypass topo

6bcd0d2

enhance TU with mixed topo kind

6b5a7f1

etiennehomer requested changes Sep 30, 2025

View reviewed changes

ghazwarhili added 2 commits September 30, 2025 17:23

EtienneH code review remarks

a48c699

add author

8bf25d4

ghazwarhili requested a review from etiennehomer September 30, 2025 15:32

etiennehomer requested changes Sep 30, 2025

View reviewed changes

ghazwarhili changed the title ~~Busbar section finder traverser breadth first search algorithm~~ Depth-first search algorithm for BusBarSection IDs Oct 1, 2025

FranckLecuyer self-requested a review October 1, 2025 07:57

etiennehomer requested changes Oct 1, 2025

View reviewed changes

FranckLecuyer requested changes Oct 1, 2025

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etiennehomer requested changes Oct 1, 2025

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etiennehomer reviewed Oct 1, 2025

View reviewed changes

etienneH code review remarks part 2

999f53c

ghazwarhili requested review from etiennehomer and FranckLecuyer October 1, 2025 11:01

ghazwarhili added 2 commits October 1, 2025 13:19

clean code

28dc2d2

add comments

dfae5ec

	private static Optional<BusbarSectionResult> tryCreateBusbarResult(VoltageLevel.NodeBreakerView view, NodePath currentNodePath) {
	private static Optional<BusbarSectionResult> getDirectlyConnectedBusbarSection(VoltageLevel.NodeBreakerView view, NodePath currentNodePath) {

	private static boolean hasNotBeenVisited(int node, Set<Integer> visited) {
	private static boolean hasBeenVisited(int node, Set<Integer> visited) {

	return !visited.contains(node);
	return visited.contains(node);

	Queue<NodePath> queue = new LinkedList<>();
	Queue<NodePath> pathsToVisit = new LinkedList<>();

	private static void exploreAdjacentNodes(VoltageLevel.NodeBreakerView view, NodePath currentNodePath, Set<Integer> visited, Queue<NodePath> queue) {
	private static void exploreAdjacentNodes(VoltageLevel.NodeBreakerView view, NodePath currentNodePath, Set<Integer> visited, Queue<NodePath> pathsToVisit) {

	private record NodePath(int node, List<SwitchInfo> pathSwitches, SwitchInfo lastSwitch) { }
	private record Path(int startNode, List<SwitchInfo> traversedSwitches, SwitchInfo lastSwitch) { }

Depth-first search algorithm for BusBarSection IDs #293

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ghazwarhili commented Sep 29, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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EtienneLt commented Sep 30, 2025

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ghazwarhili Sep 30, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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ghazwarhili commented Sep 29, 2025 •

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ghazwarhili commented Oct 1, 2025 •

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