pylon.case – Case Components

Defines the Pylon power system model.

class pylon.case.Case(name=None, base_mva=100.0, buses=None, branches=None, generators=None)

Bases: pylon.util.Named, pylon.util.Serializable

Defines representation of an electric power system as a graph of Bus objects connected by Branches.

Bdc

Returns the sparse susceptance matrices and phase shift injection vectors needed for a DC power flow [2].

The bus real power injections are related to bus voltage angles by

P = Bbus * Va + Pbusinj

The real power flows at the from end the lines are related to the bus voltage angles by

Pf = Bf * Va + Pfinj

Pf | | Bff Bft | | Vaf | | Pfinj |

| = | | * | | + | |

Pt | | Btf Btt | | Vat | | Ptinj |

[2] Ray Zimmerman, “makeBdc.m”, MATPOWER, PSERC Cornell,

http://www.pserc.cornell.edu/matpower/, version 4.0b1, Dec 2009

Sbus

Net complex bus power injection vector in p.u.

Y

Returns the bus and branch admittance matrices, Yf and Yt, such that Yf * V is the vector of complex branch currents injected at each branch’s “from” bus [1].

[1] Ray Zimmerman, “makeYbus.m”, MATPOWER, PSERC Cornell,

http://www.pserc.cornell.edu/matpower/, version 4.0b1, Dec 2009

connected_buses

Returns a list of buses that are connected to one or more branches or the first bus in a branchless system.

d2AIbr_dV2(dIbr_dVa, dIbr_dVm, Ibr, Ybr, V, lam)

Computes 2nd derivatives of |complex current|**2 w.r.t. V.

d2ASbr_dV2(dSbr_dVa, dSbr_dVm, Sbr, Cbr, Ybr, V, lam)

Computes 2nd derivatives of |complex power flow|**2 w.r.t. V.

d2Ibr_dV2(Ybr, V, lam)

Computes 2nd derivatives of complex branch current w.r.t. voltage.

d2Sbr_dV2(Cbr, Ybr, V, lam)

Computes 2nd derivatives of complex power flow w.r.t. voltage.

d2Sbus_dV2(Ybus, V, lam)

Computes 2nd derivatives of power injection w.r.t. voltage.

dAbr_dV(dSf_dVa, dSf_dVm, dSt_dVa, dSt_dVm, Sf, St)

Partial derivatives of squared flow magnitudes w.r.t voltage.

Computes partial derivatives of apparent power w.r.t active and reactive power flows. Partial derivative must equal 1 for lines with zero flow to avoid division by zero errors (1 comes from L’Hopital).

dIbr_dV(Yf, Yt, V)

Computes partial derivatives of branch currents w.r.t. voltage [4].

[4] Ray Zimmerman, “dIbr_dV.m”, MATPOWER, version 4.0b1,

PSERC (Cornell), http://www.pserc.cornell.edu/matpower/

dSbr_dV(Yf, Yt, V, buses=None, branches=None)

Computes the branch power flow vector and the partial derivative of branch power flow w.r.t voltage.

dSbus_dV(Y, V)

Computes the partial derivative of power injection w.r.t. voltage [3].

[3] Ray Zimmerman, “dSbus_dV.m”, MATPOWER, version 4.0b1,

PSERC (Cornell), http://www.pserc.cornell.edu/matpower/

deactivate_isolated()

Deactivates branches and generators connected to isolated buses.

getSbus(buses=None)

Net complex bus power injection vector in p.u.

getYbus(buses=None, branches=None)

Returns the bus and branch admittance matrices, Yf and Yt, such that Yf * V is the vector of complex branch currents injected at each branch’s “from” bus [1].

[1] Ray Zimmerman, “makeYbus.m”, MATPOWER, PSERC Cornell,

http://www.pserc.cornell.edu/matpower/, version 4.0b1, Dec 2009

index_branches(branches=None)

Updates the indices for all brnaches.

index_buses(buses=None)

Updates the indices of all case buses.

classmethod load_matpower(fd)

Returns a case from the given MATPOWER file object.

classmethod load_psat(fd)

Returns a case object from the given PSAT data file.

classmethod load_psse(fd)

Returns a case from the given PSS/E file object.

makeB(buses=None, branches=None, method='XB')

Builds the FDPF matrices, B prime and B double prime.

makeBdc(buses=None, branches=None)

Returns the sparse susceptance matrices and phase shift injection vectors needed for a DC power flow [2].

The bus real power injections are related to bus voltage angles by

P = Bbus * Va + Pbusinj

The real power flows at the from end the lines are related to the bus voltage angles by

Pf = Bf * Va + Pfinj

Pf | | Bff Bft | | Vaf | | Pfinj |

| = | | * | | + | |

Pt | | Btf Btt | | Vat | | Ptinj |

[2] Ray Zimmerman, “makeBdc.m”, MATPOWER, PSERC Cornell,

http://www.pserc.cornell.edu/matpower/, version 4.0b1, Dec 2009

online_branches

Property getter for in-service branches.

online_generators

All in-service generators.

pf_solution(Ybus, Yf, Yt, V)

Updates buses, generators and branches to match power flow solution.

reset()

Resets the result variables for all of the case componenets.

s_demand(bus)

Returns the total complex power demand.

s_supply(bus)

Returns the total complex power generation capacity.

s_surplus(bus)

Return the difference between supply and demand.

save_csv(fd)

Saves the case as a series of Comma-Separated Values.

save_dot(fd)

Saves a representation of the case in the Graphviz DOT language.

save_excel(fd)

Saves the case as an Excel spreadsheet.

save_matpower(fd)

Serialize the case as a MATPOWER data file.

save_rst(fd)

Save a reStructuredText representation of the case.

sort_generators()

Reorders the list of generators according to bus index.

class pylon.case.Bus(name=None, type='PQ', v_base=100.0, v_magnitude_guess=1.0, v_angle_guess=0.0, v_max=1.1000000000000001, v_min=0.90000000000000002, p_demand=0.0, q_demand=0.0, g_shunt=0.0, b_shunt=0.0, position=None)

Bases: pylon.util.Named

Defines a power system bus node.

reset()

Resets the result variables.

class pylon.case.Branch(from_bus, to_bus, name=None, online=True, r=0.0, x=0.0, b=0.0, rate_a=999.0, rate_b=999.0, rate_c=999.0, ratio=1.0, phase_shift=0.0, ang_min=-360.0, ang_max=360.0)

Bases: pylon.util.Named

Defines a case edge that links two Bus objects.

reset()

Resets the result variables.

Defines a generator as a complex power bus injection.

class pylon.generator.Generator(bus, name=None, online=True, base_mva=100.0, p=100.0, p_max=200.0, p_min=0.0, v_magnitude=1.0, q=0.0, q_max=30.0, q_min=-30.0, c_startup=0.0, c_shutdown=0.0, p_cost=None, pcost_model='poly', q_cost=None, qcost_model=None)

Bases: pylon.util.Named

Defines a power system generator component. Fixes voltage magnitude and active power injected at parent bus. Or when at it’s reactive power limit fixes active and reactive power injected at parent bus.

bids_to_pwl(bids)

Updates the piece-wise linear total cost function using the given bid blocks.

@see: matpower3.2/extras/smartmarket/off2case.m

get_bids(n_points=6)

Returns quantity and price bids created from the cost function.

get_offers(n_points=6)

Returns quantity and price offers created from the cost function.

is_load

Returns true if the generator if a dispatchable load. This may need to be revised to allow sensible specification of both elastic demand and pumped storage units.

offers_to_pwl(offers)

Updates the piece-wise linear total cost function using the given offer blocks.

@see: matpower3.2/extras/smartmarket/off2case.m

poly_to_pwl(n_points=10)

Sets the piece-wise linear cost attribute, converting the polynomial cost variable by evaluating at zero and then at n_points evenly spaced points between p_min and p_max.

pwl_to_poly()

Converts the first segment of the pwl cost to linear quadratic. FIXME: Curve-fit for all segments.

q_limited

Is the machine at it’s limit of reactive power?

reset()

Resets the result variables.

total_cost(p=None, p_cost=None, pcost_model=None)

Computes total cost for the generator at the given output level.