Changelog

Notable changes to HERMESS. The format follows Keep a Changelog, and versions follow Semantic Versioning as spelled out in RELEASING.md.

[1.7.2] - 2026-09-04

Fixed

• Python 3.14 compatibility: the faulted-line admittance no longer passes complex values to complex() (deprecated in 3.14, an error later), the participation heatmap uses Colormap.with_extremes instead of the deprecated set_bad, and the CLI tests keep argparse help uncolored. Results are unchanged.

[1.7.1] - 2026-09-03

Changed

• The systems shipped with the package are read-only for every helper that writes system files. hermess.analysis.set_param, set_disturbances and copy_system (also with overwrite=True, before any deletion) and the GUI’s SystemDocument.save raise a PermissionError pointing to copy_system when the target resolves to a folder under hermess.SYSTEMS_DIR; the GUI’s post-save sim_settings.txt offer skips such folders. The SEA benchmark generator scripts (hermess/systems/sea14gen/*.py), which write their case folders next to themselves, are no longer packaged in the wheel.

Fixed

• DaeSim.eigenvalue_analysis (and so hermess.analysis.small_signal, modal_table, participation_table, state_matrix and plot_modes) called after a run with a disturbance linearized the post-disturbance equations at the pre-disturbance operating point, which is not an equilibrium of them: the modes moved and a spurious real eigenvalue near zero appeared with an “operating point seems unstable” log. The run now snapshots the initial equation build at the initial operating point before the stepping, and the analysis always uses it, so a post-run analysis equals the pre-run one (small_signal_analysis=True) and the disturbance-free run of the same system. Trajectories are unchanged.

[1.7.0] - 2026-09-01

All of this release grew out of one first-time Windows test drive by an external user; thanks for the reports.

Added

• Per-system defaults: an optional sim_settings.txt in a system folder carries the configuration the system needs to run out of the box (one field = value per line, JSON values, Config field names). hermess.simulate, the command line and the GUI apply it between the package defaults and explicit arguments, so anything passed explicitly still wins. The 25 shipped networks whose buses carry no shunt susceptance now default to the quasi-static network instead of failing the dynamic-network guard on a bare run.

• The GUI’s disturbance editor explains itself: every field is labeled with the core’s meaning and units, required fields are enforced per event type, optional fields show their defaults, and the equivalent sim_dist.txt line is displayed. The tables come from the core (Disturbance._EVENT_FIELDS), so editor and simulator cannot drift.

• Saving a built network whose lines carry no charging offers once to write a sim_settings.txt with line_dyn = false next to it.

Changed

• Disturbance rows are validated when the system loads: an unknown type, a misspelled field or a missing required field stops the run with the fields, units and an example row for that type, instead of the stray field being silently ignored.

• An IDACalcIC convergence failure under dynamic lines raises a readable message, separately for the initialization at t = 0 and for the restart after a disturbance, with the raw solver error attached as the cause.

Fixed

• The built-in result plots (the default hermess run path) and the participation heatmap used matplotlib APIs removed in 3.9 (cm.get_cmap, plt.get_cmap) and crashed on any current matplotlib. The plot path now has a smoke test.

• The unknown-disturbance branch called logging.ERROR(...) (an int) and would have crashed if ever reached.

• The installation guide covers the Windows case where the hermess command is not on PATH after a user-site install.

[1.6.1] - 2026-08-31

Changed

• Relaxed the dependency floors to what the suite actually requires: numpy>=2.0 (from 2.2.4), pandas>=2.2.2 (from 2.2.3, the first numpy-2-compatible pandas) and matplotlib>=3.8.4 (from 3.8.3, which declares numpy<2 and can never coexist with the required numpy). The full test suite passes against exactly this oldest stack. On environments with a preinstalled scientific stack (e.g. Google Colab), pip install hermess now leaves numpy and pandas untouched instead of upgrading them under a live kernel.

• CasADi’s numpy-mode FutureWarning (casadi issue #2959, printed at every first simulation per call site on casadi 3.7) is silenced by explicitly keeping the legacy behavior, GlobalOptions.setNumpyMode(-1): results are bit-identical, only the notice goes away. The migration to the casadi-aware numpy mode remains deliberate future work.

[1.6.0] - 2026-08-30

Added

• hermess.analysis, the post-processing and notebook workflow as a public API: signal addressing (owner:quantity with globs, lists, dicts and device objects), pandas tables and CSV export (signals, get, to_dataframe, to_csv, metrics, summary), one-line plotting including the single-line system diagram (plot, plot_states, compare, plot_frequency, plot_voltages, plot_active_power, plot_modes, plot_system, mark_events), small-signal tables (small_signal, modal_table, participation_table, state_matrix, power_flow_table), raw accessors (get_device, frequency_hz, bus_voltage, state_index, device_label) and text-level system-file helpers (copy_system, show_system, set_param, set_disturbances, read_events). One star-import gives a notebook the whole workflow. The plots follow the active matplotlib style.

• Quiet runs: the show_progress configuration field turns the progress bar off, and hermess.simulate(..., quiet=True) is the shorthand (no progress bar, warnings-only logging).

• The returned model carries the scheduled disturbances as dae.events ((time, type, where) tuples) and the resolved configuration as dae.cfg.

[1.5.1] - 2026-08-30

Fixed

• Derived outputs (omega_c, omega_pll) are reconstructed correctly across a SETPOINT disturbance. The event bakes the new setpoint into the rebuilt expressions as a numeric constant, and the post-run evaluation used those final expressions for the whole run, shifting the pre-event segment (by Kp * (Pref_new - Pref_old) for a grid-forming converter’s frequency). Each stored segment is now evaluated with the expressions of its own equation build. Affects SimulationResults and the GUI signal tree; the stored state and algebraic trajectories were always correct.

• progress_callback and init_callback cancel the run on any falsy return other than None. A callback returning numpy bools (natural when comparing against the reported fraction) previously failed the exact is False test and the cancellation was silently ignored.

• The angle-source module docstring no longer lists the shipped VSM strategy as future work.

[1.5.0] - 2026-08-30

Added

• Device-level algebraic signals in the time-domain view: the private algebraic variables (e.g. the quasi-static filter quantities) and the outputs the models expose symbolically, such as a grid-forming converter’s frequency omega_c (or a PLL’s omega_pll), evaluated over the stored trajectories and marked “(algebraic)” in the signal tree. SimulationResults carries them per device unit.

• Topology view controls: Fit (also the space bar) refits the diagram while keeping the manual arrangement, and a Labels toggle shows or hides the device names; dense systems start decluttered, with glyph hover naming the unit.

Changed

• The GUI has a refreshed visual design (underline tabs, toolbar icons, filled active states, visible splitter handles) with no new dependencies, and everyday details were polished: the window title names the shown system with an unsaved marker, the progress bar is indeterminate while the model builds, checked signals carry color chips matching their curves, and the options dialog documents every field with tooltips.

• Large one-line diagrams lay out without overlaps: minimum node spacing is enforced, device glyphs and labels go into each bus’s locally empty sector, and the bus number takes the opposite side.

• Zooming on long large-amplitude records is smooth: traces beyond 20k points render with a thin aliased pen (measured ~270x faster per zoom step), visually indistinguishable at that density.

Fixed

• Clicking an eigenvalue in the small-signal map no longer raises a numpy truthiness error when the click selects nothing.

[1.4.0] - 2026-08-29

Added

• Lines are editable in the builder: double-clicking one opens its parameter form in edit mode, and a detail pop-up with the pi-section schematic in view mode.

• Save… and Save as… buttons in the builder palette. Save as… forks the current state into a new folder (suggested next to the original) so a variant can be kept for comparison without touching the system it started from; choosing a folder that already holds a different system asks before replacing it.

• A Clear canvas button that empties the edited system after a confirmation and stays undoable, plus undo/redo shortcuts with proper enabled states, and Escape to abandon a half-drawn line.

• The validation enforces one injector per bus as an error (with the low-impedance-branch remedy) and flags unproven device pairings and duplicate unit identifiers, live in the builder’s status line and at pre-flight.

Changed

• The builder names actual defaults instead of generic placeholders: the strategy dropdowns show what the model default resolves to, the unit identifier field shows the name that will be generated, and disturbance fields show their defaults.

• Completing a line, device or delete action drops the tool back to Move so stray clicks stay inert, and the mouse cursor indicates the active tool. While a document is edited, the systems browser is deselected and its inspector emptied, restored when edit mode ends.

Fixed

• Toggling edit mode off with unsaved changes now asks (save, discard or keep editing) instead of dropping them silently.

[1.3.0] - 2026-08-29

Added

• Graphical system builder in the GUI: the Edit toggle on the topology view opens a palette to place buses, connect lines and attach any shipped or user-registered device model by clicking on the canvas. The parameter forms are generated from the model classes, so every parameter appears with the model’s own default and description, and the control strategies (AVR, governor, PSS, shaft; filter, angle, voltage, inner control, PLL) are selected from dropdowns; fields left empty are not written, keeping generated files as terse as hand-written ones. Includes a disturbance sequence editor, undo/redo, and live validation in a status line.

• Built systems are saved as ordinary system folders (sim_param.txt + sim_dist.txt) that scripts, the CLI and version control handle like any hand-written one; parameter values round-trip verbatim. File > New system starts from a blank canvas, and editing a selected system works on a copy. Running an edited system saves it automatically once a save location has been chosen.

• The GUI’s pre-flight validation checks the summed line charging per bus when dynamic lines are enabled, mirroring the setup guard from 1.2.2, so the problem surfaces before the model is built.

[1.2.2] - 2026-08-29

Fixed

• Running with line_dyn=True on a system file without line charging now fails at setup with the names of the buses that lack shunt susceptance and the remedy, instead of an opaque integrator error at the first step. With dynamic lines the charging b acts as the bus capacitance, so every bus needs a connected branch with b > 0; the system-file guide states the requirement.

[1.2.1] - 2026-08-29

Added

• Documentation link in the package metadata, pointing at the rebuilt documentation site (https://maitrayadesai.github.io/hermess/): report-style pages, a per-family model reference generated from the code, executed example notebooks and a public API page.

• Docstrings for the core classes (Grid, GridSim, Dae, DaeSim) and the entry modules, so help() on the model returned by simulate is informative.

Changed

• The example notebooks are rebuilt as five studies, one simulator aspect each: a first run, scheduled disturbances, the hybrid EMT/RMS network, small-signal analysis and parametric sensitivities. They are executed during the documentation build, so the shown outputs always match the installed version.

• hermess.utils is a regular package instead of an implicit namespace package.

Fixed

• Opening a line no longer emits a spurious numpy overflow RuntimeWarning when the opened branch’s impedance is inverted.

[1.2.0] - 2026-08-28

Added

• Real command-line interface behind the hermess console script and python -m hermess: hermess list prints the runnable systems and hermess run <system> simulates one, with --t-end, --ts, --no-plot, --small-signal, --system-root, and --set KEY=VALUE for any other Config field. --help and --version behave as expected.

Changed

• A bare hermess (or python -m hermess) now prints the usage instead of immediately running the configuration shipped in hermess/config.py; that demo run is now hermess run ieee39_conv --small-signal. In 1.1.0 every invocation, including hermess --help, started that simulation.

[1.1.0] - 2026-08-28

First release on PyPI.

Added

• Cross-tool validation suite spanning five reference families, all compared against committed CSV references so no external tool is needed at test time: frozen own baselines, ANDES (8 machine/exciter/stabilizer cases), PSS/E (GENROU trajectory via the PSID benchmark set), PowerSimulationsDynamics.jl (converter, Sauer-Pai machine, five-mass shaft, dynamic network), and PSCAD (4 converter cases). Documented in the new validation chapter.

• New models: Marconato synchronous machine, AVRCONST, AVRSimple, IEEEDC1A and AVRAC1A exciters, PSSKundur stabilizer, TGTypeII governor, and a current-injecting grid-following converter chain with the CascadedDamped, VSMAngle, KauraPLL, ReducedPLL, PLLPowerPI, QPowerPI and CurrentPI strategies.

• SETPOINT disturbance for changing a device parameter or setpoint at a given simulation time.

• Package-level API: hermess.list_systems, hermess.simulate, hermess.register.

• Parametric build (Config(parametric=True)) exposing dae.parametric_model for gradient-based studies, tested against finite differences.

• Init callback at the initialized operating point.

• GUI pre-flight checks and per-component detail views.

• Uniform model documentation: every device and strategy docstring carries the governing equations and a symbol table, with TikZ schematics in the docs.

Changed

• Breaking: the former GridFollowing converter is renamed GridSupporting; GridFollowing now denotes the new current-injecting chain. Old parameter files using the previous meaning fail with a clear error.

• Shipped system folders renamed to a uniform lowercase scheme (3bus, ieee39, kundur, smib, …); the old names still resolve and emit a DeprecationWarning.

• Packaging moved from Poetry to uv (PEP 621 metadata, uv_build backend). Wheels no longer include the test suite. The main console script is removed; use hermess or hermess-gui.

Fixed

• The loader’s registry path dropped strategy kwargs for registered devices, and system_root did not expand ~.

• Stale state names in the lazy eigenvalue analysis.

• CSV quoting in two device symbol tables.

[1.0.0] - 2026-08-22

Initial public release, deposited in the ETH Zurich Research Collection (doi: 10.3929/ethz-c-000805609).