introduce new keywords for branch flow constraints

docs/src/manual/acOptimalPowerFlow.md

@@ -45,7 +45,7 @@ addBus!(system; label = "Bus 1", type = 3, active = 0.1, angle = -0.1)
 addBus!(system; label = "Bus 2", reactive = 0.01, magnitude = 1.1)
 
 @branch(minDiffAngle = -pi, maxDiffAngle = pi, reactance = 0.5, type = 2)
-addBranch!(system; label = "Branch 1", from = "Bus 1", to = "Bus 2", longTerm = 0.15)
+addBranch!(system; label = "Branch 1", from = "Bus 1", to = "Bus 2", maxFromBus = 0.15)
 
 @generator(maxActive = 0.5, minReactive = -0.1, maxReactive = 0.1, status = 0)
 addGenerator!(system; label = "Generator 1", bus = "Bus 1", active = 0.4, reactive = 0.2)
@@ -208,24 +208,19 @@ The `flow` field contains references to the inequality constraints associated wi
 * `type = 2` for the active power flow,
 * `type = 3` for the current flow magnitude.
 
-These limits are specified using the `longTerm` keyword within the [`addBranch!`](@ref addBranch!) function. By default, the `longTerm` keyword is linked to apparent power (`type = 1`).
+These limits are specified using the `minFromBus`, `maxFromBus`, `minToBus` and `maxToBus` keywords within the [`addBranch!`](@ref addBranch!) function. By default, these limit keywords are associated with apparent power (`type = 1`).
 
 However, in the example, we configured it to use active power flow by setting `type = 2`. To access the flow constraints of branches at the from-bus end, we can utilize the following code snippet:
 ```@repl ACOptimalPowerFlow
 print(system.branch.label, analysis.method.constraint.flow.from)
 ```
 
-Similarly, to access the to-bus end flow constraints of branches we can use the following code snippet:
-```@repl ACOptimalPowerFlow
-print(system.branch.label, analysis.method.constraint.flow.to)
-```
-
 !!! note "Info"
-    Please note that if the flow constraints are set to `longTerm = 0.0` for the corresponding branch, JuliGrid will omit the corresponding inequality constraint.
+    Please note that if the flow constraints are set to `minFromBus = 0.0` and `maxFromBus = 0.0` for the corresponding branch, JuliGrid will omit the corresponding inequality constraint at the from-bus end of the branch. The same applies to the to-bus end if `minToBus = 0.0` and `maxToBus = 0.0` are set.
 
 Additionally, by employing the [`updateBranch!`](@ref updateBranch!) function, we have the ability to modify these specific constraints:
 ```@example ACOptimalPowerFlow
-updateBranch!(system, analysis; label = "Branch 1", reactance = 1.0, longTerm = 0.14)
+updateBranch!(system, analysis; label = "Branch 1", minFromBus = -0.15, maxToBus = 0.15)
 nothing # hide
 ```
 
@@ -235,6 +230,9 @@ print(system.branch.label, analysis.method.constraint.flow.from)
 print(system.branch.label, analysis.method.constraint.flow.to)
 ```
 
+!!! tip "Tip"
+    In typical scenarios, `minFromBus` is equal to `minToBus`, and `maxFromBus` is equal to `maxToBus`. However, we allow these values to be defined separately for greater flexibility, enabling, among other things, the option to apply constraints on only one side of the branch.
+
 ---
 
 ##### Power Capability Constraints
@@ -529,9 +527,9 @@ addBus!(system; label = "Bus 2", active = 0.1, reactive = 0.01, conductance = 0.
 addBus!(system; label = "Bus 3", active = 0.05, reactive = 0.02)
 
 @branch(resistance = 0.5, reactance = 1.0, conductance = 1e-4, susceptance = 0.01)
-addBranch!(system; label = "Branch 1", from = "Bus 1", to = "Bus 2", longTerm = 0.15)
-addBranch!(system; label = "Branch 2", from = "Bus 1", to = "Bus 3", longTerm = 0.10)
-addBranch!(system; label = "Branch 3", from = "Bus 2", to = "Bus 3", longTerm = 0.25)
+addBranch!(system; label = "Branch 1", from = "Bus 1", to = "Bus 2", maxFromBus = 0.15)
+addBranch!(system; label = "Branch 2", from = "Bus 1", to = "Bus 3", maxFromBus = 0.10)
+addBranch!(system; label = "Branch 3", from = "Bus 2", to = "Bus 3", maxFromBus = 0.25)
 
 @generator(maxActive = 0.5, minReactive = -0.1, maxReactive = 0.1)
 addGenerator!(system; label = "Generator 1", bus = "Bus 1", active = 3.2, reactive = 0.5)

docs/src/manual/dcOptimalPowerFlow.md

@@ -32,7 +32,7 @@ addBus!(system; label = "Bus 1", type = 3, angle = 0.17)
 addBus!(system; label = "Bus 2", active = 0.1, conductance = 0.04)
 addBus!(system; label = "Bus 3", active = 0.05)
 
-@branch(minDiffAngle = -3.1, maxDiffAngle = 3.1, longTerm = 0.12)
+@branch(minDiffAngle = -3.1, maxDiffAngle = 3.1, maxFromBus = 0.12)
 addBranch!(system; label = "Branch 1", from = "Bus 1", to = "Bus 2", reactance = 0.05)
 addBranch!(system; label = "Branch 2", from = "Bus 1", to = "Bus 3", reactance = 0.01)
 addBranch!(system; label = "Branch 3", from = "Bus 2", to = "Bus 3", reactance = 0.01)
@@ -184,7 +184,7 @@ print(system.branch.label, analysis.method.constraint.flow.active)
 By employing the [`updateBranch!`](@ref updateBranch!) function, we have the ability to modify these specific constraints, for example:
 ```@example DCOptimalPowerFlow
 updateBranch!(system, analysis; label = "Branch 1", status = 0)
-updateBranch!(system, analysis; label = "Branch 2", reactance = 0.03, longTerm = 0.14)
+updateBranch!(system, analysis; label = "Branch 2", reactance = 0.03, maxFromBus = 0.14)
 nothing # hide
 ```
 
@@ -450,7 +450,7 @@ addBus!(system; label = "Bus 1", type = 3, angle = 0.17)
 addBus!(system; label = "Bus 2", active = 0.1, conductance = 0.04)
 addBus!(system; label = "Bus 3", active = 0.05)
 
-@branch(minDiffAngle = -pi, maxDiffAngle = pi, longTerm = 0.12)
+@branch(minDiffAngle = -pi, maxDiffAngle = pi, maxFromBus = 0.12)
 addBranch!(system; label = "Branch 1", from = "Bus 1", to = "Bus 2", reactance = 0.05)
 addBranch!(system; label = "Branch 2", from = "Bus 1", to = "Bus 3", reactance = 0.01)
 addBranch!(system; label = "Branch 3", from = "Bus 2", to = "Bus 3", reactance = 0.01)

docs/src/tutorials/acOptimalPowerFlow.md

@@ -13,7 +13,7 @@ addBus!(system; label = 1, type = 3, active = 0.1, angle = -0.1)
 addBus!(system; label = 2, reactive = 0.01, magnitude = 1.1)
 
 @branch(minDiffAngle = -pi, maxDiffAngle = pi, reactance = 0.5, type = 2)
-addBranch!(system; label = 1, from = 1, to = 2, longTerm = 0.15)
+addBranch!(system; label = 1, from = 1, to = 2, maxFromBus = 0.15, maxToBus = 0.15)
 
 @generator(maxActive = 0.5, minReactive = -0.1, maxReactive = 0.1)
 addGenerator!(system; label = 1, bus = 1, active = 0.4, reactive = 0.2)
@@ -291,7 +291,7 @@ Specifically, `type = 1` is used for apparent power flow, `type = 2` for active
 ```
 These rating constraints ensure that the power flow or current in each branch does not exceed the specified limits, helping to maintain the security and reliability of the power system. The upper bounds are determined based on the vector ``\mathbf{F}_{\text{max}} = [F_{ij}^\text{max}]``, ``(i,j) \in \mathcal{E}``. These bounds can be accessed using the following variable:
 ```@repl ACOptimalPowerFlow
-𝐅ₘₐₓ = system.branch.flow.longTerm
+𝐅ₘₐₓ = system.branch.flow.maxFromBus
 ```
 
 By default, JuliaGrid employs the rating constraints linked with the apparent power flow (`type = 1`). This constraint at the from-bus is specified as:

docs/src/tutorials/dcOptimalPowerFlow.md

@@ -13,9 +13,9 @@ addBus!(system; label = 2, type = 2, active = 0.1, conductance = 0.04)
 addBus!(system; label = 3, type = 1, active = 0.05)
 
 @branch(minDiffAngle = -pi, maxDiffAngle = pi)
-addBranch!(system; label = 1, from = 1, to = 2, reactance = 0.05, longTerm = 0.15)
-addBranch!(system; label = 2, from = 1, to = 3, reactance = 0.01, longTerm = 0.10)
-addBranch!(system; label = 3, from = 2, to = 3, reactance = 0.01, longTerm = 0.25)
+addBranch!(system; label = 1, from = 1, to = 2, reactance = 0.05, maxFromBus = 0.15)
+addBranch!(system; label = 2, from = 1, to = 3, reactance = 0.01, maxFromBus = 0.10)
+addBranch!(system; label = 3, from = 2, to = 3, reactance = 0.01, maxFromBus = 0.25)
 
 @generator(minActive = 0.0)
 addGenerator!(system; label = 1, bus = 1, active = 3.2, maxActive = 0.5)
@@ -229,7 +229,7 @@ The inequality constraint related to active power flow is used to represent ther
 ```
 Here, the lower and upper bounds are determined based on the vector ``\mathbf{P}_{\text{max}} = [P_{ij}^\text{max}]``, ``(i,j) \in \mathcal{E}``. These bounds can be accessed using the following variable:
 ```@repl DCOptimalPowerFlow
-𝐏ₘₐₓ = system.branch.flow.longTerm
+𝐏ₘₐₓ = system.branch.flow.maxFromBus
 ```
 
 The active power flow at branch ``(i,j) \in \mathcal{E}`` can be derived using the [Branch Network Equations](@ref DCBranchNetworkEquationsTutorials) and is given by:

src/definition/internal.jl

@@ -112,9 +112,10 @@ Base.@kwdef mutable struct BranchTemplate
     shiftAngle::ContainerTemplate = ContainerTemplate()
     minDiffAngle::ContainerTemplate = ContainerTemplate(-2*pi, true)
     maxDiffAngle::ContainerTemplate = ContainerTemplate(2*pi, true)
-    longTerm::ContainerTemplate = ContainerTemplate()
-    shortTerm::ContainerTemplate = ContainerTemplate()
-    emergency::ContainerTemplate = ContainerTemplate()
+    minFromBus::ContainerTemplate = ContainerTemplate()
+    maxFromBus::ContainerTemplate = ContainerTemplate()
+    minToBus::ContainerTemplate = ContainerTemplate()
+    maxToBus::ContainerTemplate = ContainerTemplate()
     label::String = "?"
     turnsRatio::Float64 = 1.0
     status::Int8 = Int8(1)

src/definition/system.jl

@@ -54,9 +54,10 @@ mutable struct BranchParameter
 end
 
 mutable struct BranchFlow
-    longTerm::Array{Float64,1}
-    shortTerm::Array{Float64,1}
-    emergency::Array{Float64,1}
+    minFromBus::Array{Float64,1}
+    maxFromBus::Array{Float64,1}
+    minToBus::Array{Float64,1}
+    maxToBus::Array{Float64,1}
     type::Array{Int8,1}
 end
 

src/optimalPowerFlow/acOptimalPowerFlow.jl

@@ -496,7 +496,10 @@ function addFlow(system::PowerSystem, jump::JuMP.Model, magnitude::Vector{Variab
     branch = system.branch
     ac = system.model.ac
 
-    if branch.flow.longTerm[i] ≉  0 && branch.flow.longTerm[i] < 10^16
+    fromBus = branch.flow.minFromBus[i] != 0.0 || branch.flow.maxFromBus[i] != 0.0
+    toBus = branch.flow.minToBus[i] != 0.0 || branch.flow.maxToBus[i] != 0.0
+
+    if fromBus || toBus
         from = branch.layout.from[i]
         to = branch.layout.to[i]
 
@@ -523,22 +526,42 @@ function addFlow(system::PowerSystem, jump::JuMP.Model, magnitude::Vector{Variab
             Dji = βij * (gij * bsi - bij * gsi)
 
             if branch.flow.type[i] == 1
-                refFrom[i] = @constraint(jump, 0 <= sqrt(Aij * Vi^4 + Bij * Vi^2 * Vj^2 - 2 * Vi^3 * Vj * (Cij * cosθ - Dij * sinθ)) <= branch.flow.longTerm[i])
-                refTo[i] = @constraint(jump, 0 <= sqrt(Aji * Vj^4 + Bij * Vi^2 * Vj^2 - 2 * Vi * Vj^3 * (Cji * cosθ + Dji * sinθ)) <= branch.flow.longTerm[i])
+                if fromBus
+                    refFrom[i] = @constraint(jump, branch.flow.minFromBus[i] <= sqrt(Aij * Vi^4 + Bij * Vi^2 * Vj^2 - 2 * Vi^3 * Vj * (Cij * cosθ - Dij * sinθ)) <= branch.flow.maxFromBus[i])
+                end
+                if toBus
+                    refTo[i] = @constraint(jump, branch.flow.minToBus[i] <= sqrt(Aji * Vj^4 + Bij * Vi^2 * Vj^2 - 2 * Vi * Vj^3 * (Cji * cosθ + Dji * sinθ)) <= branch.flow.maxToBus[i])
+                end
             elseif branch.flow.type[i] == 3
-                refFrom[i] = @constraint(jump,  0 <= sqrt(Aij * Vi^2 + Bij * Vj^2 - 2 * Vi * Vj * (Cij * cosθ - Dij * sinθ)) <= branch.flow.longTerm[i])
-                refTo[i] = @constraint(jump,  0 <= sqrt(Aji * Vj^2 + Bij * Vi^2 - 2 * Vi * Vj * (Cji * cosθ + Dji * sinθ)) <= branch.flow.longTerm[i])
+                if fromBus
+                    refFrom[i] = @constraint(jump, branch.flow.minFromBus[i] <= sqrt(Aij * Vi^2 + Bij * Vj^2 - 2 * Vi * Vj * (Cij * cosθ - Dij * sinθ)) <= branch.flow.maxFromBus[i])
+                end
+                if toBus
+                    refTo[i] = @constraint(jump, branch.flow.minToBus[i] <= sqrt(Aji * Vj^2 + Bij * Vi^2 - 2 * Vi * Vj * (Cji * cosθ + Dji * sinθ)) <= branch.flow.maxToBus[i])
+                end
             end
         elseif branch.flow.type[i] == 2
             if gij != 0 && bij != 0
-                refFrom[i] = @constraint(jump, -branch.flow.longTerm[i] <= βij^2 * (gij + gsi) * Vi^2 - βij * Vi * Vj * (gij * cosθ + bij * sinθ) <= branch.flow.longTerm[i])
-                refTo[i] = @constraint(jump, -branch.flow.longTerm[i] <= (gij + gsi) * Vj^2 - βij * Vi * Vj * (gij * cosθ - bij * sinθ) <= branch.flow.longTerm[i])
+                if fromBus
+                    refFrom[i] = @constraint(jump, branch.flow.minFromBus[i] <= βij^2 * (gij + gsi) * Vi^2 - βij * Vi * Vj * (gij * cosθ + bij * sinθ) <= branch.flow.maxFromBus[i])
+                end
+                if toBus
+                    refTo[i] = @constraint(jump, branch.flow.minToBus[i] <= (gij + gsi) * Vj^2 - βij * Vi * Vj * (gij * cosθ - bij * sinθ) <= branch.flow.maxToBus[i])
+                end
             elseif gij != 0
-                refFrom[i] = @constraint(jump, -branch.flow.longTerm[i] <= βij^2 * (gij + gsi) * Vi^2 - βij * Vi * Vj * gij * cosθ  <= branch.flow.longTerm[i])
-                refTo[i] = @constraint(jump, -branch.flow.longTerm[i] <= (gij + gsi) * Vj^2 - βij * Vi * Vj * gij * cosθ <= branch.flow.longTerm[i])
+                if fromBus
+                    refFrom[i] = @constraint(jump, branch.flow.minFromBus[i] <= βij^2 * (gij + gsi) * Vi^2 - βij * Vi * Vj * gij * cosθ <= branch.flow.maxFromBus[i])
+                end
+                if toBus
+                    refTo[i] = @constraint(jump, branch.flow.minToBus[i] <= (gij + gsi) * Vj^2 - βij * Vi * Vj * gij * cosθ <= branch.flow.maxToBus[i])
+                end
             elseif bij != 0
-                refFrom[i] = @constraint(jump, -branch.flow.longTerm[i] <= βij^2 * (gij + gsi) * Vi^2 - βij * Vi * Vj * bij * sinθ <= branch.flow.longTerm[i])
-                refTo[i] = @constraint(jump, -branch.flow.longTerm[i] <= (gij + gsi) * Vj^2 + βij * Vi * Vj * bij * sinθ <= branch.flow.longTerm[i])
+                if fromBus
+                    refFrom[i] = @constraint(jump, branch.flow.minFromBus[i] <= βij^2 * (gij + gsi) * Vi^2 - βij * Vi * Vj * bij * sinθ <= branch.flow.maxFromBus[i])
+                end
+                if toBus
+                    refTo[i] = @constraint(jump, branch.flow.minToBus[i] <= (gij + gsi) * Vj^2 + βij * Vi * Vj * bij * sinθ <= branch.flow.maxToBus[i])
+                end
             end
         end
     end

src/optimalPowerFlow/dcOptimalPowerFlow.jl

@@ -223,11 +223,11 @@ function addBalance(system::PowerSystem, jump::JuMP.Model, active::Vector{Variab
 end
 
 ######### Flow Constraints ##########
-function addFlow(system::PowerSystem, jump::JuMP.Model, angle::Vector{VariableRef}, ref::Dict{Int64, ConstraintRef}, index::Int64)
+function addFlow(system::PowerSystem, jump::JuMP.Model, angle::Vector{VariableRef}, ref::Dict{Int64, ConstraintRef}, i::Int64)
     branch = system.branch
-    if branch.flow.longTerm[index] ≉  0 && branch.flow.longTerm[index] < 10^16
-        restriction = branch.flow.longTerm[index] / system.model.dc.admittance[index]
-        ref[index] = @constraint(jump, - restriction + branch.parameter.shiftAngle[index] <= angle[branch.layout.from[index]] - angle[branch.layout.to[index]] <= restriction + branch.parameter.shiftAngle[index])
+
+    if branch.flow.minFromBus[i] != 0.0 || branch.flow.maxFromBus[i] != 0.0
+        ref[i] = @constraint(jump, branch.flow.minFromBus[i] <= system.model.dc.admittance[i] * (angle[branch.layout.from[i]] - angle[branch.layout.to[i]] - branch.parameter.shiftAngle[i]) <= branch.flow.maxFromBus[i])
     end
 
     return jump, ref