fix bug in calc_theta_delta_bounds (#908)

 closes #907

CHANGELOG.md

@@ -4,6 +4,9 @@ PowerModels.jl Change Log
 ### Staged
 - nothing
 
+### v0.21.1
+- Fix bug in `calc_theta_delta_bounds` (#907)
+
 ### v0.21.0
 - Update to new JuMP nonlinear interface (breaking)
 

Project.toml

@@ -2,7 +2,7 @@ name = "PowerModels"
 uuid = "c36e90e8-916a-50a6-bd94-075b64ef4655"
 authors = ["Carleton Coffrin"]
 repo = "https://github.com/lanl-ansi/PowerModels.jl"
-version = "0.21.0"
+version = "0.21.1"
 
 [deps]
 InfrastructureModels = "2030c09a-7f63-5d83-885d-db604e0e9cc0"

src/core/data.jl

@@ -50,7 +50,18 @@ function calc_theta_delta_bounds(data::Dict{String,<:Any})
     sort!(angle_mins)
     sort!(angle_maxs, rev=true)
 
-    return angle_mins[1], angle_maxs[1]
+    if length(angle_mins) > 1
+        # note that, this can occur when dclines are present
+        angle_count = min(bus_count-1, length(branches))
+
+        angle_min_val = sum(angle_mins[1:angle_count])
+        angle_max_val = sum(angle_maxs[1:angle_count])
+    else
+        angle_min_val = angle_mins[1]
+        angle_max_val = angle_maxs[1]
+    end
+
+    return angle_min_val, angle_max_val
 end
 
 

test/data.jl

@@ -603,6 +603,35 @@ end
 end
 
 
+@testset "test theta delta bounds" begin
+
+    @testset "5-bus test" begin
+        data = PowerModels.parse_file("../test/data/matpower/case5.m")
+        theta_lb, theta_ub = calc_theta_delta_bounds(data)
+
+        @test theta_lb[1] <= -2.0
+        @test theta_ub[1] >=  2.0
+    end
+
+    @testset "14-bus test" begin
+        data = PowerModels.parse_file("../test/data/matpower/case14.m")
+        theta_lb, theta_ub = calc_theta_delta_bounds(data)
+
+        @test theta_lb[1] <= -13.0
+        @test theta_ub[1] >=  13.0
+    end
+
+    @testset "30-bus test" begin
+        data = PowerModels.parse_file("../test/data/matpower/case30.m")
+        theta_lb, theta_ub = calc_theta_delta_bounds(data)
+
+        @test theta_lb[1] <= -15.0
+        @test theta_ub[1] >=  15.0
+    end
+
+end
+
+
 @testset "test branch flow computations" begin
 
      @testset "5-bus ac polar flow" begin