Reformat source code

src/model/formulations/Gar1962/status.jl

@@ -2,12 +2,6 @@
 # Copyright (C) 2020, UChicago Argonne, LLC. All rights reserved.
 # Released under the modified BSD license. See COPYING.md for more details.
 
-"""
-    _add_status_vars!
-
-Adds symbols identified by `Gar1962.StatusVars` to `model`.
-Fix variables if a certain generator _must_ run or based on initial conditions.
-"""
 function _add_status_vars!(
     model::JuMP.Model,
     g::Unit,
@@ -16,93 +10,15 @@ function _add_status_vars!(
     is_on = _init(model, :is_on)
     switch_on = _init(model, :switch_on)
     switch_off = _init(model, :switch_off)
-    FIX_VARS = !formulation_status_vars.fix_vars_via_constraint
-    is_initially_on = _is_initially_on(g) > 0
     for t in 1:model[:instance].time
+        if g.must_run[t]
+            is_on[g.name, t] = 1.0
+            switch_on[g.name, t] = (t == 1 ? 1.0 - _is_initially_on(g) : 0.0)
+            switch_off[g.name, t] = 0.0
+        else
             is_on[g.name, t] = @variable(model, binary = true)
             switch_on[g.name, t] = @variable(model, binary = true)
             switch_off[g.name, t] = @variable(model, binary = true)
-
-        # Use initial conditions and whether a unit must run to fix variables
-        if FIX_VARS
-            # Fix variables using fix function
-            if g.must_run[t]
-                # If the generator _must_ run, then it is obviously on and cannot be switched off
-                # In the first time period, force unit to switch on if was off before
-                # Otherwise, unit is on, and will never turn off, so will never need to turn on
-                fix(is_on[g.name, t], 1.0; force = true)
-                fix(
-                    switch_on[g.name, t],
-                    (t == 1 ? 1.0 - _is_initially_on(g) : 0.0);
-                    force = true,
-                )
-                fix(switch_off[g.name, t], 0.0; force = true)
-            elseif t == 1
-                if is_initially_on
-                    # Generator was on (for g.initial_status time periods),
-                    # so cannot be more switched on until the period after the first time it can be turned off
-                    fix(switch_on[g.name, 1], 0.0; force = true)
-                else
-                    # Generator is initially off (for -g.initial_status time periods)
-                    # Cannot be switched off more
-                    fix(switch_off[g.name, 1], 0.0; force = true)
-                end
-            end
-        else
-            # Add explicit constraint if !FIX_VARS
-            if g.must_run[t]
-                is_on[g.name, t] = 1.0
-                switch_on[g.name, t] =
-                    (t == 1 ? 1.0 - _is_initially_on(g) : 0.0)
-                switch_off[g.name, t] = 0.0
-            elseif t == 1
-                if is_initially_on
-                    switch_on[g.name, t] = 0.0
-                else
-                    switch_off[g.name, t] = 0.0
-                end
-            end
-        end
-
-        # Use initial conditions and whether a unit must run to fix variables
-        if FIX_VARS
-            # Fix variables using fix function
-            if g.must_run[t]
-                # If the generator _must_ run, then it is obviously on and cannot be switched off
-                # In the first time period, force unit to switch on if was off before
-                # Otherwise, unit is on, and will never turn off, so will never need to turn on
-                fix(is_on[g.name, t], 1.0; force = true)
-                fix(
-                    switch_on[g.name, t],
-                    (t == 1 ? 1.0 - _is_initially_on(g) : 0.0);
-                    force = true,
-                )
-                fix(switch_off[g.name, t], 0.0; force = true)
-            elseif t == 1
-                if is_initially_on
-                    # Generator was on (for g.initial_status time periods),
-                    # so cannot be more switched on until the period after the first time it can be turned off
-                    fix(switch_on[g.name, 1], 0.0; force = true)
-                else
-                    # Generator is initially off (for -g.initial_status time periods)
-                    # Cannot be switched off more
-                    fix(switch_off[g.name, 1], 0.0; force = true)
-                end
-            end
-        else
-            # Add explicit constraint if !FIX_VARS
-            if g.must_run[t]
-                is_on[g.name, t] = 1.0
-                switch_on[g.name, t] =
-                    (t == 1 ? 1.0 - _is_initially_on(g) : 0.0)
-                switch_off[g.name, t] = 0.0
-            elseif t == 1
-                if is_initially_on
-                    switch_on[g.name, t] = 0.0
-                else
-                    switch_off[g.name, t] = 0.0
-                end
-            end
         end
     end
     return

src/model/formulations/Gar1962/structs.jl

@@ -17,53 +17,8 @@ import ..PiecewiseLinearCostsFormulation
 import ..ProductionVarsFormulation
 import ..StatusVarsFormulation
 
-"""
-Variables
----
-* `prod_above`:
-        [gen, t];
-        *production above minimum required level*;
-        lb: 0, ub: Inf.
-        KnuOstWat2020: `p'_g(t)`
-* `segprod`:
-        [gen, segment, t];
-        *how much generator produces on cost segment in time t*;
-        lb: 0, ub: Inf.
-        KnuOstWat2020: `p_g^l(t)`
-"""
 struct ProdVars <: ProductionVarsFormulation end
-
 struct PwlCosts <: PiecewiseLinearCostsFormulation end
-
-"""
-Variables
----
-* `is_on`:
-        [gen, t];
-        *is generator on at time t?*
-        lb: 0, ub: 1, binary.
-        KnuOstWat2020: `u_g(t)`
-* `switch_on`:
-        [gen, t];
-        *indicator that generator will be turned on at t*;
-        lb: 0, ub: 1, binary.
-        KnuOstWat2020: `v_g(t)`
-* `switch_off`: binary;
-        [gen, t];
-        *indicator that generator will be turned off at t*;
-        lb: 0, ub: 1, binary.
-        KnuOstWat2020: `w_g(t)`
-
-Arguments
----
-* `fix_vars_via_constraint`:
-        indicator for whether to set vars to a constant using `fix` or by adding an explicit constraint
-        (particulary useful for debugging purposes).
-"""
-struct StatusVars <: StatusVarsFormulation
-    fix_vars_via_constraint::Bool
-
-    StatusVars() = new(false)
-end
+struct StatusVars <: StatusVarsFormulation end
 
 end

src/model/formulations/GenMorRam2017/startstop.jl

@@ -0,0 +1,96 @@
+# UnitCommitment.jl: Optimization Package for Security-Constrained Unit Commitment
+# Copyright (C) 2020, UChicago Argonne, LLC. All rights reserved.
+# Released under the modified BSD license. See COPYING.md for more details.
+
+"""
+    _add_startup_shutdown_limit_eqs!(model::JuMP.Model, g::Unit)::Nothing
+
+Startup and shutdown limits from Gentile et al. (2017).
+Eqns. (20), (23a), and (23b) in Knueven et al. (2020).
+
+Creates constraints `eq_startstop_limit`,  `eq_startup_limit`, and `eq_shutdown_limit`
+using variables `Gar1962.StatusVars`, `prod_above` from `Gar1962.ProdVars`, and `reserve`.
+
+Constraints
+---
+* `eq_startstop_limit`
+* `eq_startup_limit`
+* `eq_shutdown_limit`
+"""
+function _add_startup_shutdown_limit_eqs!(
+    model::JuMP.Model,
+    g::Unit,
+    formulation_prod_vars::Gar1962.ProdVars,
+    formulation_status_vars::Gar1962.StatusVars,
+)::Nothing
+    # TODO: Move upper case constants to model[:instance]
+    RESERVES_WHEN_START_UP = true
+    RESERVES_WHEN_RAMP_UP = true
+    RESERVES_WHEN_RAMP_DOWN = true
+    RESERVES_WHEN_SHUT_DOWN = true
+
+    eq_startstop_limit = _init(model, :eq_startstop_limit)
+    eq_shutdown_limit = _init(model, :eq_shutdown_limit)
+    eq_startup_limit = _init(model, :eq_startup_limit)
+
+    is_on = model[:is_on]
+    prod_above = model[:prod_above]
+    reserve = model[:reserve]
+    switch_off = model[:switch_off]
+    switch_on = model[:switch_on]
+
+    T = model[:instance].time
+    gi = g.name
+
+    if g.initial_power > g.shutdown_limit
+        eqs.shutdown_limit[gi, 0] =
+            @constraint(mip, vars.switch_off[gi, 1] <= 0)
+    end
+
+    for t in 1:T
+        ## 2020-10-09 amk: added eqn (20) and check of g.min_uptime
+        # Not present in (23) in Kneueven et al.
+        if g.min_uptime > 1
+            # Equation (20) in Knueven et al. (2020)
+            eqs.startstop_limit[gi, t] = @constraint(
+                model,
+                prod_above[gi, t] + reserve[gi, t] <=
+                (g.max_power[t] - g.min_power[t]) * is_on[gi, t] -
+                max(0, g.max_power[t] - g.startup_limit) * switch_on[gi, t] - (
+                    t < T ?
+                    max(0, g.max_power[t] - g.shutdown_limit) *
+                    switch_off[gi, t+1] : 0.0
+                )
+            )
+        else
+            ## Startup limits
+            # Equation (23a) in Knueven et al. (2020)
+            eqs.startup_limit[gi, t] = @constraint(
+                model,
+                prod_above[gi, t] + reserve[gi, t] <=
+                (g.max_power[t] - g.min_power[t]) * is_on[gi, t] -
+                max(0, g.max_power[t] - g.startup_limit) * switch_on[gi, t] - (
+                    t < T ?
+                    max(0, g.startup_limit - g.shutdown_limit) *
+                    switch_off[gi, t+1] : 0.0
+                )
+            )
+
+            ## Shutdown limits
+            if t < T
+                # Equation (23b) in Knueven et al. (2020)
+                eqs.shutdown_limit[gi, t] = @constraint(
+                    model,
+                    prod_above[gi, t] + reserve[gi, t] <=
+                    (g.max_power[t] - g.min_power[t]) * xis_on[gi, t] - (
+                        t < T ?
+                        max(0, g.max_power[t] - g.shutdown_limit) *
+                        switch_off[gi, t+1] : 0.0
+                    ) -
+                    max(0, g.shutdown_limit - g.startup_limit) *
+                    switch_on[gi, t]
+                )
+            end
+        end
+    end
+end

src/model/formulations/MorLatRam2013/startstop.jl

@@ -0,0 +1,89 @@
+# UnitCommitment.jl: Optimization Package for Security-Constrained Unit Commitment
+# Copyright (C) 2020, UChicago Argonne, LLC. All rights reserved.
+# Released under the modified BSD license. See COPYING.md for more details.
+
+"""
+    _add_startup_shutdown_limit_eqs!(model::JuMP.Model, g::Unit)::Nothing
+
+Startup and shutdown limits from Morales-España et al. (2013a).
+Eqns. (20), (21a), and (21b) in Knueven et al. (2020).
+
+Uses variable `prod_above` from `Gar1962.ProdVars`, the variables in `Gar1962.StatusVars`, and `reserve`
+to generate constraints below.
+
+Constraints
+---
+* :eq_startstop_limit
+* :eq_startup_limit
+* :eq_shutdown_limit
+"""
+function _add_startup_shutdown_limit_eqs!(
+    model::JuMP.Model,
+    g::Unit,
+    formulation_prod_vars::Gar1962.ProdVars,
+    formulation_status_vars::Gar1962.StatusVars,
+)::Nothing
+    # TODO: Move upper case constants to model[:instance]
+    RESERVES_WHEN_START_UP = true
+    RESERVES_WHEN_RAMP_UP = true
+    RESERVES_WHEN_RAMP_DOWN = true
+    RESERVES_WHEN_SHUT_DOWN = true
+
+    eq_startstop_limit = _init(model, :eq_startstop_limit)
+    eq_shutdown_limit = _init(model, :eq_shutdown_limit)
+    eq_startup_limit = _init(model, :eq_startup_limit)
+
+    is_on = model[:is_on]
+    prod_above = model[:prod_above]
+    reserve = model[:reserve]
+    switch_off = model[:switch_off]
+    switch_on = model[:switch_on]
+
+    T = model[:instance].time
+    gi = g.name
+    for t in 1:T
+        ## 2020-10-09 amk: added eqn (20) and check of g.min_uptime
+        if g.min_uptime > 1 && t < T
+            # Equation (20) in Knueven et al. (2020)
+            # UT > 1 required, to guarantee that vars.switch_on[gi, t] and vars.switch_off[gi, t+1] are not both = 1 at the same time
+            eq_startstop_limit[gi, t] = @constraint(
+                model,
+                prod_above[gi, t] + reserve[gi, t] <=
+                (g.max_power[t] - g.min_power[t]) * is_on[gi, t] -
+                max(0, g.max_power[t] - g.startup_limit) * switch_on[gi, t] -
+                max(0, g.max_power[t] - g.shutdown_limit) * switch_off[gi, t+1]
+            )
+        else
+            ## Startup limits
+            # Equation (21a) in Knueven et al. (2020)
+            # Proposed by Morales-España et al. (2013a)
+            eqs_startup_limit[gi, t] = @constraint(
+                model,
+                prod_above[gi, t] + reserve[gi, t] <=
+                (g.max_power[t] - g.min_power[t]) * is_on[gi, t] -
+                max(0, g.max_power[t] - g.startup_limit) * switch_on[gi, t]
+            )
+
+            ## Shutdown limits
+            if t < T
+                # Equation (21b) in Knueven et al. (2020)
+                # TODO different from what was in previous model, due to reserve variable
+                # ax: ideally should have reserve_up and reserve_down variables
+                #     i.e., the generator should be able to increase/decrease production as specified
+                #     (this is a heuristic for a "robust" solution,
+                #     in case there is an outage or a surge, and flow has to be redirected)
+                # amk: if shutdown_limit is the max prod of generator in time period before shutting down,
+                #      then it makes sense to count reserves, because otherwise, if reserves ≠ 0,
+                #      then the generator will actually produce more than the limit
+                eqs.shutdown_limit[gi, t] = @constraint(
+                    model,
+                    prod_above[gi, t] +
+                    (RESERVES_WHEN_SHUT_DOWN ? reserve[gi, t] : 0.0) <=
+                    (g.max_power[t] - g.min_power[t]) * is_on[gi, t] -
+                    max(0, g.max_power[t] - g.shutdown_limit) *
+                    switch_off[gi, t+1]
+                )
+            end
+        end
+    end
+end

src/model/formulations/base/unit.jl

@@ -2,15 +2,6 @@
 # Copyright (C) 2020, UChicago Argonne, LLC. All rights reserved.
 # Released under the modified BSD license. See COPYING.md for more details.
 
-"""
-    _add_unit!(model::JuMP.Model, g::Unit, formulation::Formulation)
-
-Add production, reserve, startup, shutdown, and status variables,
-and constraints for min uptime/downtime, net injection, production, ramping, startup, shutdown, and status.
-
-Fix variables if a certain generator _must_ run or if a generator provides spinning reserves.
-Also, add overflow penalty to objective for each transmission line.
-"""
 function _add_unit!(model::JuMP.Model, g::Unit, formulation::Formulation)
     if !all(g.must_run) && any(g.must_run)
         error("Partially must-run units are not currently supported")
@@ -47,8 +38,8 @@ function _add_unit!(model::JuMP.Model, g::Unit, formulation::Formulation)
     _add_startup_shutdown_limit_eqs!(
         model,
         g,
-        formulation.status_vars,
         formulation.prod_vars,
+        formulation.status_vars,
     )
     _add_status_eqs!(model, g, formulation.status_vars)
     return
@@ -103,8 +94,8 @@ Constraints
 function _add_startup_shutdown_limit_eqs!(
     model::JuMP.Model,
     g::Unit,
-    formulation_status_vars::Gar1962.StatusVars,
     formulation_prod_vars::Gar1962.ProdVars,
+    formulation_status_vars::Gar1962.StatusVars,
 )::Nothing
     eq_shutdown_limit = _init(model, :eq_shutdown_limit)
     eq_startup_limit = _init(model, :eq_startup_limit)
@@ -124,15 +115,8 @@ function _add_startup_shutdown_limit_eqs!(
         )
         # Shutdown limit
         if g.initial_power > g.shutdown_limit
-            # TODO check what happens with these variables when exporting the model
-            # Generator producing too much to be turned off in the first time period
-            # (can a binary variable have bounds x = 0?)
-            if formulation_status_vars.fix_vars_via_constraint
             eq_shutdown_limit[g.name, 0] =
-                    @constraint(model, model[:switch_off][g.name, 1] <= 0.0)
-            else
-                fix(model[:switch_off][g.name, 1], 0.0; force = true)
-            end
+                @constraint(model, switch_off[g.name, 1] <= 0)
         end
         if t < T
             eq_shutdown_limit[g.name, t] = @constraint(