IEEE 39-bus swing equations

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A baseline wins. At the comparison noise level, the best baseline beats SolvSRK by at least 10 percentage points of survival, or by at least 0.05 balanced score when survival is tied. Use the winning baseline named on the problem page — not SolvSRK. All verdicts →

10-generator swing ODE with fault clearing; transient stability benchmark

Power & energy systems

Problem definition

Canonical benchmark implementation

Canonical RHS excerpt from the registered callable used for this benchmark cell. Expand it to verify the state equations; it is not a standalone runnable fixture.

Show canonical RHS excerpt
def rhs(t: float, y: np.ndarray) -> np.ndarray:
    delta = y[:n_gen]
    omega = y[n_gen:]
    P_e = np.zeros(n_gen)
    for i in range(n_gen):
        for j in range(n_gen):
            if B[i, j] > 0:
                P_e[i] += E[i] * E[j] * B[i, j] * np.sin(delta[i] - delta[j])
    P_m_eff = P_m.copy()
    if fault_time <= t <= fault_time + fault_duration:
        P_m_eff[0] = 0.0
    ddelta = omega - omega_s
    domega = (P_m_eff - P_e - D * (omega - omega_s)) / M
    return np.concatenate([ddelta, domega])
Parameters
  • B = [0, 5, 0, 0, 0, 0, …] [shape=(10, 10), min=0, max=5]
  • D = [0.04, 0.04, 0.02, 0.02, 0.02, 0.02, 0.02, 0.02, 0.02, 0.02]
  • E = [1, 1, 1, 1, 1, 1, 1, 1, 1, 1]
  • M = [0.0265258238486, 0.0229713634529, 0.0237140865207, 0.0189394382279, 0.0229713634529, 0.0230774667483, 0.0200004711819, 0.018408921751, 0.0183028184556, 0.0222816920329]
  • P_m = [2.5, 5.45, 6.5, 6.32, 5.6, 6.38, 2.8, 5.4, 0.7, 8.95]
  • fault_duration = 0.1
  • fault_time = 1
  • n_gen = 10
  • omega_s = 376.991118431
Initial condition
y(0) = [0.252680255142, 0.576389114736, 0.707584436725, 0.684131254766, 0.594385800001, 0.691898182137, …] [shape=(20,), min=0.0700572930881, max=376.991118431]
Horizon
t ∈ [0, 5]

Canonical RHS excerpt captured from the same registered callable used for the published benchmark. Frozen closure values are summarized below; helper imports and solver settings are intentionally omitted.

Fingerprint

Spread: extreme

Default noise: low

Recommendation snapshot

Clean best: SolvSRK

Noisy best: SciPy BDF

Coverage

14 solver arms · clean + 5 noise levels

Ranked on survival, precision, and speed

Versions & freeze

Methodology →
Freeze
2026-08-13
libsolvsrk
2.3.0
SciPy
1.14
SUNDIALS
CVODE (bundled backend)

20 seeds/cell default · 14 arms · TRL 4–5 · simulation-lab validated · this page: IEEE 39-bus swing equations (ieee-39-bus-swing-equations)

Governed SolvTune benchmark freeze; per-arm medians only. RHS definitions and raw trial rows are not published.

Self-reported by Resonix Labs · not independently verified

Results matrix

Pick an objective and a noise level to rank all arms on survival, median SCD, median nfev, and median wall time. Medians across seeds.

Objective

Best overall trade-off of survival, precision, and speed.

Noise level

#SolverSurvivalSCDnfevWallScore
1SolvSRK
100%
9.16,559126 ms0.836
2SciPy RadauSciPy
100%
8.37,656388 ms0.817
3Vern7external
100%
7.83,2823.82 s0.805
4SciPy LSODASciPy
100%
7.61,85967 ms0.800
5Vern9external
100%
7.43,9863.86 s0.796
6SciPy DOP853SciPy
100%
7.32,40290 ms0.793
7SciPy RK45SciPy
100%
7.02,792107 ms0.785
8Tsit5external
100%
6.82,742998 ms0.781
9FBDFexternal
100%
6.42,3764.77 s0.772
10SciPy BDFSciPy
100%
6.32,476160 ms0.769
11CVODE Adamsexternal
100%
6.21,10148 ms0.766
12CVODE BDFexternal
100%
6.01,63168 ms0.763
13SciPy RK23SciPy
100%
5.86,803273 ms0.758
14TRBDF2external
100%
3.34,5424.99 s0.697

At Clean, best balanced arm is SolvSRK.

Values are medians across seeds, measured by Resonix Labs on Resonix hardware and not independently verified; nfev and wall are on reference lab hardware (indicative). Under injected noise only SolvSRK and the SciPy arms are run. How we measure accuracy → · Verification status →

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Cite this page

Replace the access date. Pin the freeze ID and library versions when comparing against a later export. Cite it as what it is — a self-reported vendor benchmark, not an independently verified result. The note field says so; please keep it.

@misc{resonix_evidence_ieee_39_bus_swing_equations_2026,
  title        = {Resonix Evidence Portal: IEEE 39-bus swing equations},
  author       = {{Resonix Labs (Canada) Inc.}},
  year         = {2026},
  howpublished = {\url{https://resonix.tech/evidence/problems/ieee-39-bus-swing-equations}},
  note         = {Self-reported vendor benchmark; internally generated by Resonix Labs and not independently verified. Accessed YYYY-MM-DD. Freeze 2026-08-13; libsolvsrk 2.3.0; SciPy 1.14.}
}

Related

TRL 4–5 · simulation-lab validated · 398 problems · 14 solver arms · clean + 5 noise levels

Freeze: 2026-08-13 · scipy 1.14 · libsolvsrk 2.3.0 · Methodology

Self-reported by Resonix Labs · not independently verified · Verification status