description: Every element in OpenDSS Designer and the OpenDSS parameters behind it: sources, busbars, transformers, breakers, lines, loads, capacitors, generators, PV systems and storage.¶
Components¶
Every element you can place from the palette, with its OpenDSS parameters. Placement is sticky — click a palette item (or press its shortcut letter), then click the canvas repeatedly to drop several; press Esc to stop. Symbols are ANSI one-line style, and every element can be rotated with R.
Parameters are edited in the properties panel (select the element) or in bulk on the Elements spreadsheet. Anything not listed here is left at its OpenDSS default.
Phases¶
Every element carries a Phases count and a Phase(s) picker. The count is how many conductors it has; the picker says which of A, B and C those are, and is what makes single-phase laterals real rather than decorative.
Left at (default) an element takes the first N phases — one phase means A,
two means A-B — which is exactly what OpenDSS assumes when a connection names
no nodes, so a drawing made before the picker existed still means what it
always did. Pick a phase and the connection is written with the matching node
suffix instead: B becomes bus1=lateral.2.
A pin follows the element. A line, a switch and a regulator keep it on both ends, because they sit inside one lateral. A transformer does not: its pin names the phase it taps off the primary, and the low side starts at A again, which is what lets a single-phase pole-top transformer feed an ordinary secondary.
Lines that are not carrying all three phases show the phase beside their name on the one-line. Nothing is labelled when it carries A-B-C, so the laterals are the ones that stand out.
Pinning is checked. The Problems list works out which phases actually reach each bus by walking out from the source, and warns when an element asks for one that never gets there — a lateral pinned to C hanging off a bus fed only by A is a dead element, and the solve would otherwise report it as a voltage of zero rather than as a mistake. Setting a 3-phase element to a single phase is an error, not a warning, since OpenDSS cannot build it.
An imported .dss connection the letters cannot spell — a neutral (.1.0), a
centre tap — is kept exactly as written and shown as "(as imported)"; the
picker leaves it alone rather than dropping a node.
Source — S¶
An OpenDSS Vsource; the first one placed defines the circuit. Every circuit
needs at least one.
| Parameter | Meaning |
|---|---|
| Base kV (LL) | Line-to-line source voltage |
| Voltage (pu) | Per-unit setpoint |
| Angle (°) | Reference angle |
| Phases | 1 / 2 / 3 |
| 3φ / 1φ short-circuit (MVA) | Thévenin strength (mvasc3, mvasc1) — drives fault-study results |
Busbar — B¶
A stretchable bus with connection handles along its top and bottom edges. Drag horizontally while placing to set its width; drag the end grips later to resize (connections re-home automatically if the bar shrinks). The declared base kV is used for validation and voltage-base calculation.
Busbars are optional: wiring elements directly together creates an implicit
junction bus. Name a busbar and that name is used in solves and .dss
exports.
Transformer — T¶
Two windings by default, three when a tertiary is added, with a per-winding editor:
| Parameter | Meaning |
|---|---|
| Phases | 1 or 3 |
| X(H-L) (%) | Leakage reactance between the primary and secondary |
| X(H-T), X(L-T) (%) | The other two leakage reactances of a three-winding unit; shown only once it has a tertiary, and taken equal to X(H-L) when left blank |
| Load loss (%) | Winding losses at rated load |
| Per winding: kV, kVA, wye/delta | Ratings and connection for each side |
Add tertiary winding in the properties panel gives the symbol a third
circle and a third terminal, t3, leaving the symbol to the right; the name
moves to the left to stay clear of it. Like the secondary, the tertiary is a
new voltage level whose phases start at A. Removing the tertiary removes the
terminal, and any wire on it. Three-winding transformers in a .dss file
import with all three windings and both extra reactances.
Regulator — V¶
A step-voltage regulator: an equal-ratio transformer plus the RegControl
that moves its taps to hold the load-side voltage. Settings are the ones on a
real control cabinet, expressed on the 120 V control base.
| Parameter | Meaning |
|---|---|
| Phases | 1 or 3 |
| Rated kV, kVA | Same kV both sides — a regulator boosts, it does not transform |
| Voltage setpoint | Target voltage on the 120 V base (122 V is typical) |
| Bandwidth | Total deadband around the setpoint, so ±half this |
| PT ratio | Turns the line voltage into the 120 V base. Left blank, it is derived from the rated kV |
| CT primary | Current transformer primary rating, used by line drop compensation |
| Line drop comp R, X | Volts of compensation, to regulate a point out on the feeder rather than at the regulator |
| Max tap change / solution | Taps the control may move in one solution |
The tap position is chosen by OpenDSS during the solve; the diagram shows the
resulting voltages. Importing a .dss file turns any transformer with a
RegControl on it back into a regulator.
Breaker / switch — K¶
Emitted as a zero-impedance OpenDSS switch. Double-click (or right-click) to open/close it; an open breaker de-energizes everything downstream.
| Parameter | Meaning |
|---|---|
| Closed | Switch state |
| Rating (A) | normamps, used for the loading overlay |
| Interrupting rating (kA) | What it can break; checked against the fault current available at its bus |
| Phases | 1 / 2 / 3 |
A breaker has no protection of its own
It carries no time-current curve and never trips by itself — it is the switch someone operates: a tie point, a sectionalizing point, an isolation switch. That is why breakers have no curve in the Protection plot; they appear in the table beneath it instead, where their interrupting rating is checked against the fault duty.
For a breaker that trips on overcurrent, use a relay — that element is exactly this breaker plus the relay that watches it, which is how the two are drawn on a real one-line.
Fuse — F, Recloser — O, Relay — Y¶
Protective devices. Each one is a switch on the diagram plus the control that watches it, and the editor keeps the pair together as a single element — the switch is what carries current, so loading and losses report against it.
Right-click (or double-click) blows a fuse or opens a recloser or relay, the same way a breaker opens. Anything downstream goes dead, which is how you check what a device protects.
Fuse
| Parameter | Meaning |
|---|---|
| Intact | Uncheck to blow it |
| Rated current | The link's rating, in amps |
| Fuse link | tlink or klink — the standard link curves |
| Added delay | Seconds added to the curve's time |
| Continuous rating | normamps, used for the loading overlay |
Recloser
| Parameter | Meaning |
|---|---|
| Phase / ground pickup | Trip current, in amps |
| Fast / delayed curve | a and d are the standard fast and delayed curves |
| Ground fast / delayed curve | Leave at none for no ground unit; the ground pickup alone does not create one |
| Fast operations | How many trips use the fast curve before switching to the delayed one |
| Shots to lockout | Trips before it stays open |
Relay (overcurrent, IEEE C37.2 device 51 — 51N once a ground curve is set)
Drawn the way a one-line draws it: the breaker sits in the line, the relay is its own circled device number beside it, and the dashed link between them is the trip signal. It is a breaker with protection — use it wherever a breaker should trip on overcurrent rather than be opened by hand.
| Parameter | Meaning |
|---|---|
| Phase / ground pickup | Trip current, in amps |
| Phase / ground curve | mod_inv, very_inv, ext_inv (IEEE moderately, very and extremely inverse) or definite |
Ground curve none |
No ground unit at all, which is different from one set to a default |
Every curve dropdown offers the ten built into the OpenDSS engine plus any curve this circuit defines in the Curves tab (bottom panel), where you can type a manufacturer's table in as pairs of "multiple of pickup, seconds". The dropdown is limited to curves that exist because naming one the engine does not hold stops the solve outright; a curve that goes missing falls back to the device's default and says so in the Problems list.
Their curves are plotted in the Graph tab → Protection — see Analysis.
What these do today
The controls describe how each device would operate, and the Protection plot shows when. OpenDSS itself runs protection in fault and time-domain studies, so in a snapshot or a time-series run these behave as closed switches with ratings — nothing trips mid-run. Automatic coordination checks between devices are the next step on the roadmap.
Load — L¶
| Parameter | Meaning |
|---|---|
| Rated kV | Line-to-line for 3φ/wye conventions per OpenDSS |
| Power (kW) | Rated demand at multiplier 1.0 |
| Power factor | Positive = lagging |
| Phases, Connection | 1/2/3, wye/delta |
| Load model | OpenDSS models 1–5 (1 = constant P/Q) |
| Loadshape | A load shape that scales the load over time-series runs |
In a snapshot solve, loads draw their full rated kW; the loadshape applies only to time-series runs.
Capacitor — C¶
Shunt capacitor bank: rated kV, size (kvar), phases, wye/delta, and number of switched steps.
Generator — G¶
| Parameter | Meaning |
|---|---|
| Rated kV, Output (kW), Power factor | Machine ratings |
| Rating (kVA) | What the loading overlay and the report judge the machine against; left blank it is 1.2 × kW, OpenDSS's own default |
| Mode | 1 = constant kW/pf; 3 = PV mode (holds a voltage setpoint) |
| V setpoint (pu) | Held voltage in mode 3 |
Reliability data¶
Every line, transformer, regulator, breaker, fuse, recloser and relay ends its property list with the inputs of the reliability study: Fault rate (per year, or per unit length per year for a line), Permanent faults (%), Repair time (h) and a Reliability meter here checkbox that makes the element the head of a metered zone. Loads have Customers. Blank fields take OpenDSS's defaults (0.1, 20 %, 3 h and 1 customer), which is also what an imported file gets unless it set them, and the export writes only what you set.
PV system — P¶
An OpenDSS PVSystem: panel + inverter, with built-in inverter efficiency
and power–temperature curves.
| Parameter | Meaning |
|---|---|
| Rated kV | Interconnection voltage |
| Inverter rating (kVA) | Caps output |
| Panel Pmpp (kW) | Array rating at 1 kW/m² and 25 °C |
| Power factor | Inverter pf |
| Irradiance (pu) | Base irradiance in kW/m²; output ≈ Pmpp × irradiance × efficiency |
| Irradiance shape | An irradiance shape that scales the base irradiance over time-series runs |
In a snapshot solve, the PV system produces at its base irradiance (the shape is not applied). Fetch real regional irradiance from the NSRDB in the Shapes tab.
Storage — A¶
An OpenDSS Storage element (battery).
| Parameter | Meaning |
|---|---|
| Power rating (kW), Energy rating (kWh) | Inverter and pack ratings |
| Initial charge (%) | State of charge at the start of a run |
| Reserve (%) | SOC floor the dispatch will not discharge below |
| Charge / discharge eff. (%) | One-way efficiencies |
| Dispatch mode | follow or default (below) |
| Dispatch shape | Shape driving follow mode |
| Charge / discharge trigger | Thresholds for default mode |
Dispatch modes:
- follow — the assigned shape drives the battery directly each step: positive multiplier = discharge (× kW rating), negative = charge. This is the primary mode; hand-craft a dispatch curve in the Shapes tab, or reuse a load shape.
- default — OpenDSS's built-in triggered dispatch, where the triggers
compare against the circuit's default loadshape multiplier. Documented as
advanced; prefer
follow.
Storage only acts during time-series runs; in a snapshot it idles. Storage elements are excluded from fault studies (a crash in the underlying DSS engine — their fault contribution is negligible anyway).
Note — N¶
A note is text on the drawing, not an element: the engine never sees it. Click to place one and type; Ctrl+Enter, Esc or clicking away finishes, and double-clicking a note edits it again. Line breaks you type are kept, and long lines wrap at the note's width, which you set by dragging either side of a selected note.
Right-click an element or a line and choose Add note pointing here to write a note with an arrow to it; the arrow follows the element when either moves, and Clean up moves the note along with it. Points at in the properties panel changes or removes the arrow, and Text size and Box set how it looks. Right-click empty canvas for Add note here.
Notes appear in image exports and study reports, Find (Ctrl+F)
searches their text, and an exported .dss file keeps each one as a
! Note: comment — above the element it points at, or after the file's
header. Importing that file back reads them as ordinary comments, not
notes. Editing a note never makes the results stale.
Zone — Z¶
A zone is a labelled, tinted rectangle drawn behind a group of elements — a substation, a feeder, a service area, the part of the drawing a note is about — the way the planning tools' one-lines mark them. Press Z (or the palette's Zone, or Edit → Add zone) and drag out the rectangle; a plain click drops a default-size one. The properties panel sets its Label and Colour; drag the handles of a selected zone to resize it.
A zone lets the pointer through: clicking or box-selecting over it works
on the elements inside, and the zone itself is picked up by its border or
its label. It is drawing only, like a note: it is never compiled, never
counts against a size limit, never makes results stale, and Clean up
redraws it around the elements it held wherever they end up. Zones go
into image exports and study reports with the drawing, Find matches
their labels, and an exported .dss file records each one as a
! Zone: <label> - <elements inside> comment.
Wires vs. Lines¶
Dragging between two terminals creates a connection whose kind follows the Wire / Line mode buttons (W / E):
- Wire — an ideal connection; the two terminals become the same OpenDSS bus (merged via union-find under the hood).
- Line — a real OpenDSS
Lineelement: length + units, ampacity, phases, and an impedance that comes from one of three places, chosen under Conductor in the properties panel: a line code the circuit carries (below), a preset fromconfig/linecodes.csvthat stamps sequence values into the R1/X1/R0/X0 fields, or those fields typed directly.
Line codes¶
A line code is a conductor definition lines share by name — OpenDSS's
LineCode. Real feeder models define their conductors this way, as a full
phase impedance matrix (R, X and optionally C, one row per phase, in ohms
and nF per unit length) rather than four sequence numbers, because the
matrix carries the mutual coupling between phases and the asymmetry of a
real pole configuration. Four sequence numbers cannot.
The Line codes tab in the bottom panel holds the circuit's library. An
imported .dss file brings the codes its lines use (a shared code file's
unused entries are left out, and the import says how many). Add your own
with + New line code: pick the phase count and units, then paste the R
and X matrices exactly as a .dss file or a conductor table writes them —
the lower triangle, rows separated by |:
0.3465 | 0.1560 0.3375 | 0.1580 0.1535 0.3414
A code can instead hold sequence values (R1/X1/R0/X0 and optional C1/C0),
which the engine expands to a balanced matrix; that is the same thing a
preset is, kept with the circuit. A line on a code hides its own R/X fields
since they would not be used, takes the code's phase count, and inherits the
code's rating unless it has one of its own. A line whose code has a
different phase count is a validation error rather than a silent resize.
Codes save with the circuit, export as LineCode objects and come back on
import unchanged; the validation page shows the IEEE test
feeders surviving that round trip to the last digit.
Picking a connect mode exits placement mode, so the next connection is always the kind you chose. While a placement mode is active, connections default to plain wires (you're dropping components and hooking them up as you go). Illegal connections — busbar-to-busbar wires, self-connections, duplicates — are refused with an explanation. Double-click any wire or line to add a draggable routing point; double-click a point to remove it. The new point lands on the wire and the elbows the router had already drawn become routing points too, so adding one never changes the shape you were looking at — right-click and Straighten hands the edge back to the auto-router.
Re-routing a connection¶
Dragging from a terminal that already holds exactly one wire picks that wire up instead of drawing a second one: its end follows the cursor while the far end stays put, so moving a line from one component to another is a single gesture. Drop it on any terminal to re-home it — the same rules apply, and a refused drop says why. Drop it on empty canvas, or press Esc mid-drag, and the wire snaps back untouched.
Terminals carrying two or more wires are left alone (there would be no telling which one the drag meant), and holding Alt always draws a new wire. A terminal never stops being a valid drop target, so a second connection is still made the usual way: start the drag at the other end.
Routing points survive a move between handles of the same component — walking a wire along a busbar keeps its shape — and are cleared when the end lands on a different component, where the old path no longer means anything.
Spreadsheet view¶
The Elements tab lists every element type in an editable table — one sub-tab per type, including PV systems and storage. Edit values in bulk with an Excel-style fill-down handle; loadshape columns are dropdowns into the shape library. Click ⌖ to locate any element on the diagram. After a solve, a read-only bus-results table appears alongside.
Editor quality of life¶
Undo/redo (Ctrl+Z / Ctrl+Y), copy/paste/duplicate (Ctrl+C / Ctrl+V / Ctrl+D), delete, rotation (R), grid snapping, pan/zoom with minimap, box-select and group-move, drag-to-re-route connections, right-click context menus, and result tooltips throughout. Your work autosaves to the browser between sessions.