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Merged
merged 1 commit into from
Sep 19, 2021
Merged

Tidyup Basic Jacobian Feature #789

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3 changes: 2 additions & 1 deletion CHANGELOG.md
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Original file line number Diff line number Diff line change
Expand Up @@ -2,7 +2,8 @@ PowerModels.jl Change Log
=========================

### Staged
- Improved support in `build_pf` for slack buses with multiple generators
- Added Jacobian calculation of basic network data (#762)
- Improved support in `build_pf` for slack buses with multiple generators (#785)
- Fixed bug in `compute_ac_pf` when reporting slack bus `va` values
- Fixed bug in `constraint_ohms_yt_from_on_off` for DCP models on branches with negative reactance values

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2 changes: 2 additions & 0 deletions docs/src/basic-data-utilities.md
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Expand Up @@ -48,6 +48,7 @@ calc_basic_incidence_matrix
calc_basic_admittance_matrix
calc_basic_susceptance_matrix
calc_basic_branch_susceptance_matrix
calc_basic_jacobian_matrix
calc_basic_ptdf_matrix
calc_basic_ptdf_row
```
Expand Down Expand Up @@ -104,6 +105,7 @@ basic network data using Julia's native linear equation solver,
compute_basic_dc_pf
```


!!! tip
By default PowerModels uses Julia's SparseArrays to ensure the best
performance of matrix operations on large power network datasets.
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71 changes: 1 addition & 70 deletions src/core/data_basic.jl
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Expand Up @@ -385,76 +385,6 @@ function calc_basic_ptdf_row(data::Dict{String,<:Any}, branch_index::Int)
return ptdf_column
end

"""
Computes the jacobian submatrices
H = dP/dδ
L = dQ/dV

The derivatives are ordered according to the bus number,
H[1, 1] is ∂P_1 / ∂δ_1
H[1, 2] is ∂P_1 / ∂δ_2

It does not exclude PV buses rows and columns
"""
function calc_basic_decoupled_jacobian_matrices(data::Dict{String,<:Any})
if !get(data, "basic_network", false)
Memento.warn(_LOGGER, "calc_basic_decoupled_jacobian_matrices requires basic network data and given data may be incompatible. make_basic_network can be used to transform data into the appropriate form.")
end
num_bus = length(data["bus"])
v = calc_basic_bus_voltage(data)
vm, va = abs.(v), angle.(v)
Y = calc_basic_admittance_matrix(data)
neighbors = [Set{Int}([i]) for i in 1:num_bus]
I, J, V = findnz(Y)
for nz in eachindex(V)
push!(neighbors[I[nz]], J[nz])
push!(neighbors[J[nz]], I[nz])
end
H0_I = Int64[]; H0_J = Int64[]; H0_V = Float64[];
L0_I = Int64[]; L0_J = Int64[]; L0_V = Float64[];
for i in 1:num_bus
for j in neighbors[i]
push!(H0_I, i); push!(H0_J, j); push!(H0_V, 0.0)
push!(L0_I, i); push!(L0_J, j); push!(L0_V, 0.0)
end
end
H = sparse(H0_I, H0_J, H0_V)
L = sparse(L0_I, L0_J, L0_V)
for i in 1:num_bus
for j in neighbors[i]
bus_type = data["bus"]["$(j)"]["bus_type"]
if bus_type == 1
if i == j
y_ii = Y[i,i]
H[i, j] = + vm[i] * sum( -real(Y[i,k]) * vm[k] * sin(va[i] - va[k]) + imag(Y[i,k]) * vm[k] * cos(va[i] - va[k]) for k in neighbors[i] if k != i )
L[i, j] = - 2*imag(y_ii)*vm[i] + sum( real(Y[i,k]) * vm[k] * sin(va[i] - va[k]) - imag(Y[i,k]) * vm[k] * cos(va[i] - va[k]) for k in neighbors[i] if k != i )
else
y_ij = Y[i,j]
H[i, j] = vm[i] * vm[j] * ( real(y_ij) * sin(va[i] - va[j]) - imag(y_ij) * cos(va[i] - va[j]) )
L[i, j] = vm[i] * ( real(y_ij) * sin(va[i] - va[j]) - imag(y_ij) * cos(va[i] - va[j]) )
end
elseif bus_type == 2
if i == j
y_ii = Y[i,i]
H[i, j] = vm[i] * sum( -real(Y[i,k]) * vm[k] * sin(va[i] - va[k]) + imag(Y[i,k]) * vm[k] * cos(va[i] - va[k]) for k in neighbors[i] if k != i )
L[i, j] = 1.0
else
y_ij = Y[i,j]
H[i, j] = vm[i] * vm[j] * ( real(y_ij) * sin(va[i] - va[j]) - imag(y_ij) * cos(va[i] - va[j]) )
L[i, j] = 0.0
end
elseif bus_type == 3
if i == j
H[i, j] = 1.0
L[i, j] = 1.0
end
else
@assert false
end
end
end
return H, L
end

"""
given a basic network data dict, returns a sparse real valued Jacobian matrix
Expand All @@ -465,6 +395,7 @@ function calc_basic_jacobian_matrix(data::Dict{String,<:Any})
if !get(data, "basic_network", false)
Memento.warn(_LOGGER, "calc_basic_jacobian_matrix requires basic network data and given data may be incompatible. make_basic_network can be used to transform data into the appropriate form.")
end

num_bus = length(data["bus"])
v = calc_basic_bus_voltage(data)
vm, va = abs.(v), angle.(v)
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15 changes: 5 additions & 10 deletions test/common.jl
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Expand Up @@ -72,7 +72,7 @@ end
"""
An AC Power Flow Solver from scratch.
"""
function compute_basic_ac_pf!(data::Dict{String, Any}; decoupled=false)
function compute_basic_ac_pf!(data::Dict{String, Any})
if !get(data, "basic_network", false)
Memento.warn(_LOGGER, "compute_basic_ac_pf requires basic network data and given data may be incompatible. make_basic_network can be used to transform data into the appropriate form.")
end
Expand Down Expand Up @@ -104,16 +104,11 @@ function compute_basic_ac_pf!(data::Dict{String, Any}; decoupled=false)
if LinearAlgebra.normInf([delta_P; delta_Q]) < tol
break
end

# STEP 2 and 3: Compute the jacobian and update step
if !decoupled
J = calc_basic_jacobian_matrix(data)
x = J \ [delta_P; delta_Q]
else
H, L = calc_basic_decoupled_jacobian_matrices(data)
va = H \ delta_P
vm = L \ delta_Q
x = [va; vm]
end
J = calc_basic_jacobian_matrix(data)
x = J \ [delta_P; delta_Q]

# STEP 4
# update voltage variables
for i in 1:bus_num
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30 changes: 2 additions & 28 deletions test/data-basic.jl
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Expand Up @@ -195,7 +195,7 @@ end
for (i, bus) in data["bus"] # All buses PQ
bus["bus_type"] = 1
end
J = PowerModels.calc_basic_jacobian_matrix(data);
J = calc_basic_jacobian_matrix(data)

num_bus = length(data["bus"])

Expand All @@ -212,7 +212,7 @@ end

@testset "24-bus-case" begin
data = make_basic_network(PowerModels.parse_file("../test/data/matpower/case24.m"))
J = PowerModels.calc_basic_jacobian_matrix(data)
J = calc_basic_jacobian_matrix(data)

num_bus = length(data["bus"])

Expand Down Expand Up @@ -244,15 +244,6 @@ end
@test isapprox(J[3, num_bus+9], -2.1624; atol=1e-4) # dP/dvm non-diagonal
@test isapprox(J[num_bus+3, num_bus+9], -7.9603; atol=1e-4) # dQ/dvm non-diagonal
end

@testset "30-bus-case-decoupled-matrices" begin
data = make_basic_network(PowerModels.parse_file("../test/data/matpower/case24.m"))
H, L = calc_basic_decoupled_jacobian_matrices(data)
J = calc_basic_jacobian_matrix(data)
n = length(data["bus"])
@test isapprox(J[1:n, 1:n], H; atol=1e-6)
@test isapprox(J[n+1:end, n+1:end], L; atol=1e-6)
end
end

@testset "basic ac power flow" begin
Expand All @@ -273,23 +264,6 @@ end
end
end

@testset "9-bus-case" begin
data = make_basic_network(PowerModels.parse_file("../test/data/matpower/case9.m"))
solution = compute_ac_pf(data)["solution"]

compute_basic_ac_pf!(data; decoupled=true)

for (i, bus) in data["bus"]
@test isapprox(solution["bus"][i]["va"], bus["va"]; atol=1e-4)
@test isapprox(solution["bus"][i]["vm"], bus["vm"]; atol=1e-4)
end

for (i, gen) in data["gen"]
@test isapprox(solution["gen"][i]["pg"], gen["pg"]; atol=1e-4)
@test isapprox(solution["gen"][i]["qg"], gen["qg"]; atol=1e-4)
end
end

@testset "14-bus-case" begin
data = make_basic_network(PowerModels.parse_file("../test/data/matpower/case14.m"))
solution = compute_ac_pf(data)["solution"]
Expand Down