Protection settings user flows

This page describes how you set up protection devices in the single-line edit panel and in the Protection view.

Where you work

You set up a protection device in two places:

1. The edit panel on the single-line diagram, for choosing the part and its trip curve while you

draw.

1. The Protection view, for editing settings, comparing curves on TCCs, and reviewing study

results.

Both places save to the same device.

1. Choose the device and its curve

1. Select a breaker or fuse on the single-line diagram and open the Equipment tab in the edit

panel.

1. For an LV breaker, pick the part in Frame.
2. Pick the trip package in Trip Unit Model, the fuse in Fuse Model, or the relay in

Protective Relay Model. A breaker with a built-in thermal-magnetic trip shows it as Built in and skips this step.

1. For an LV breaker or fuse, pick the curve in Trip curve. A trip unit imported from an ETAP

library, such as a Siemens 3VA electronic trip unit, has no Trip curve pick: it starts on its slowest dial settings, and you set its dials in the Protection view.

Each pick saves at once. When you pick a part with only one trip curve, or a default one, ekx applies that curve for you. If the pick replaces the catalogue device already assigned, click Apply — replaces the assigned device to confirm. An Apply trip curve button appears only when a curve is shown but not yet applied; it reads Reapply trip curve when the device settings or catalogue curve changed since it was applied, and Try again after a failed apply.

The edit panel lists the device's settings read-only under Settings. Click Go to Protection View to edit them. View curve in Device Catalog opens the source curves.

2. Edit settings in the Protection view

The Settings tab of the selected device groups its settings by protection function, such as long time, short time, instantaneous and ground fault. Editing a setting re-renders the active plot immediately.

A new trip unit or adjustable breaker starts at its slowest published settings: each pickup at its highest value and each delay at its longest, with instantaneous on. A breaker whose settings come only from published curves reads as its slowest curve until you choose one. This keeps an unset device from showing less arc flash energy than its real settings could give, so set each value to match the installed device. When the catalogue has a curve for only some delays, a new device starts at the longest of those. At a delay with no published curve, the plot shows that function's pickup line and the settings say "trip time unavailable for this delay". On a saved TCC, its print preview and PDF, the device's label adds a line such as "Long-time delay: trip time not published".

A trip unit imported from an ETAP library shows the dials of the real trip unit, with the same names and positions, such as a long-time delay band "GG (8s)". The frame and sensor ratings read from the parts and cannot be edited here. Each dial change saves at once, redraws the curve, and undoes in one step. A band of 0 seconds is a real dial position: it trips as fast as the breaker can, so the curve shows the breaker's own clearing range, not 0 seconds. Pickups that accept any value in steps, such as an ETU 856 long-time pickup in 1 A steps, take a typed value; a value off the step shows an error and is not saved. These trip units offer no ground fault and no instantaneous off, because the source library does not.

A Siemens 3VA ETU 350 follows Siemens' published behaviour where its ETAP record differs: the long-time delay is timed at 6 x Ir and the short-time pickup and delay follow Ir, so lowering Ir moves the whole curve. Short-time pickup positions show their amperes at the chosen Ir, such as "300 A (BB)" at Ir 150 A.

Some settings are kept with the device but no study, curve or arc flash calculation uses them: zone selective interlocking, maintenance mode, a relay's negative-sequence, directional, reclosing and reset settings, an overload relay's trip time at 6x and thermal memory, and a fuse's tabulated melt and clear times. When a device holds one of these, it appears read-only at the end of the settings under "Not modelled in studies", in both the Protection view and the edit panel. Arc flash does not credit maintenance mode, so model a faster trip by changing the pickups and delays above it.

3. Relay and HV breaker flow

Trigger: the selected device is an HV breaker with protective relay settings.

Flow:

1. Show two related blocks:

• Breaker mechanical/electrical ratings
• Protective relay settings

1. User selects relay model.
2. User sets the overcurrent elements on the relay's settings sheet (see below). Directional or

reclose settings, when supported, keep their own rows.

1. TCC preview shows relay curves.
2. User enters the breaker's interruption time in the Breaker clearing group (see below). After a short-circuit study, the Latest study tab shows evaluated operating time and explicitly identifies whether the available curve is usable as clearing time.

UX requirements:

• Make it clear which settings belong to the relay versus the breaker.
• Do not present relay settings as breaker nameplate data.

Set the relay's overcurrent elements

In the Protection workspace, a catalogued relay's Overcurrent elements group shows every element the relay offers (51P, 50P, 51G, 50G, 51N, 50N) as one row, in that order. Each row has a switch, a pickup dial, a curve, a time dial and a time adder or delay. An element that is off reads the settings it starts at when you switch it on.

A new relay starts with 51P on, its pickup at the breaker's rated current through the CT (600 A on a 600:5 CT is 5.00 A secondary), and every other element off. Arc flash uses the 51P time until you switch 50P on.

1. Choose the CT ratio under Relay inputs and CTs. Every pickup range depends on it, so the

rows stay dimmed until a ratio is chosen.

1. Turn a dial by dragging up or down, scrolling, or using the arrow keys. It stops on round

values; hold Shift to move by the relay's own step. To set an exact value, type it in the box under the dial and press Enter. The relay rounds it to its step, so 800 A on a 600:5 CT becomes 800.4 A (6.67 A secondary).

1. Watch the plot: the setting being tried draws dashed until the dial comes to rest, then saves.

Cmd+Z (Ctrl+Z) undoes it.

A pri and A sec above the rows switch the unit pickups are shown and typed in; the relay stores secondary amps either way. A typed value outside the relay's range is refused, and the box says the limit in both units. The 51P dial marks the breaker rating and the 50P dial the reduced arcing current, so you can see where a setting sits against them.

Clears in shows how long the breaker takes to clear the bolted, arcing and reduced arcing currents through this device, from the latest arc flash run: relay operating time plus the breaker clearing time below. Fault location names the bus these currents belong to. When several buses are available, choose another in that selector to update the clearing times and dial marks. The initial choice is the bus with the highest bolted current; it does not necessarily have the slowest clearing time. The fastest element for each current is green, and a line under the rows names the element that clears each one. A current below every pickup reads "the relay does not trip". Times appear once the breaker has a clearing time and arc flash has run; neutral elements show none until the study calculates the current through the neutral CT.

The sheet shows a loading message while it opens. If its context cannot be read, use Retry relay settings. A failed refresh keeps the last loaded settings visible and says that fault-current freshness could not be checked.

The device catalogue shows the same sheet on a relay's page, where you can try settings on its plot without saving anything.

Enter breaker clearing time

A relay curve gives the relay's operating time only. Arc flash adds the breaker's own interruption time to it, so a relay-operated breaker needs that time before arc flash can use the relay.

The three times belong to the breaker, so they appear under the breaker in both the single-line edit panel and the Protection workspace's Breaker clearing group, never under the relay.

The single-line panel also lists the part's other ratings read-only: Interrupting Medium, Rated Max Voltage, Rated Current, Interrupting Rating and Close and Latch. Rated Max Voltage is the part's maximum, apart from the device's own Rated Voltage above it.

Choosing a breaker part also sets the device's Rated Current and Interrupting Rating from the part, so the short-circuit duty check and reports use them. A part's interrupting rating applies up to its rated maximum voltage, for example 40 kA @ 15,000 V. When the part lists no interrupting rating, you enter it in the panel headline. The relay never supplies one.

When you first mount a relay, its CT ratio is the smallest ratio the relay lists that covers the device's Rated Current, for example 1200:5 for a 1200 A breaker. With no rated current, it is the first ratio listed. Change it in the Protection workspace under Relay inputs and CTs.

1. Select the breaker on the single-line diagram, or in the Protection workspace.
2. Enter Total clearing time in cycles, for example 5. If the manufacturer gives only opening and arcing times, leave Total clearing time blank and enter Opening time and Arcing time instead.
3. Press Enter or leave the field. The value saves at once; Escape restores the saved value, and Cmd+Z (Ctrl+Z) undoes the change.

On a breaker with no part chosen, the first time you enter adds a generic breaker to hold it. Undo removes the generic breaker again. Choosing a breaker part under Breaker model later replaces it with that part's own times.

How arc flash uses the values:

For example, a relay that operates in 0.100 s with a 5-cycle breaker clears in 0.183 s at 60 Hz and 0.200 s at 50 Hz. Arc flash applies this at both the full and reduced arcing current.

> Note: Entering a total keeps the opening and arcing times. Clear the total to use them again.

Times must be greater than 0 and use at most three decimal places; fractions of a cycle are allowed. The values apply to every scenario. Changing them marks earlier short-circuit and arc flash results stale. The short-circuit Time column continues to show relay operating time; the arc flash results show the complete clearing time.

Project viewers see the saved values as text.

4. Protection workspace

Trigger: you open Protection from the project mode tabs, the edit panel's Go to Protection View link, or an old /protection-settings URL (those redirect).

The workspace is one page at /app/project/:id/protection. The selected device (device) drives the centre pane. The active plot (tcc) drives the right pane. Those two selections are independent, except that choosing a TCC auto-selects its first member device. A saved TCC starts with every curve equally visible. Click a curve or its label box to highlight it; that also opens the device in the centre pane. Choosing a device in the list does not highlight the plot.

Flow:

1. Left pane lists devices and transformers (search, Show, Type) or saved TCCs. Badges show only

work to do: Choose model, Add rating, No curve. To delete a device, open its row's actions menu and choose Delete. The dialog states what goes with the device, such as its trip unit and settings, and that its connections on the single-line diagram are removed too. A delete cannot be undone.

1. Centre pane shows the selected device name, an always-open Device card (frame, part, trip unit,

read-only rating chips), and settings grouped by protection function. Tabs: Settings, Latest study.

1. Right pane plots the live selected device, a multi-selection preview, or a saved TCC. Editing a

setting re-renders the active plot immediately.

1. The Latest study tab loads result detail only for the selected device, 50 rows at a time.

Previous and Next load adjacent pages without placing the full study in the browser. It shows the baseline or scenario study run, fault location, function, current, operating time, freshness, and any unavailable-current explanation. A setting, curve, catalog/SKU, CT, override, or relevant short-circuit-input change keeps the old row visible but labels it historical and requires a rerun before use. Legacy studies without fingerprints or with an unsupported current-attribution contract are explicitly unverified. Refresh checks both short-circuit and arc-flash results. Failed reads show an error; failed refreshes keep the last loaded results and say when freshness could not be checked.

1. Create a TCC by selecting devices in the list and choosing Add to TCC > New TCC, or with

New TCC in the TCC list. Add further devices with Add to plot, or select them and choose a saved TCC from the Add to TCC menu. In Plot settings, Remove takes a device or transformer off the saved TCC and Hide hides one of its curves.

1. Open on single-line returns to the same device on the SLD. Print preview stays a separate page.

Add device creates an unconnected device. Cmd+Z (Ctrl+Z) removes that creation in one step; redo restores the same device. Undo refuses if another edit or connection has changed the device. A fuse without a selected model shows no catalogue curve card.

Selecting a published setting saves its rating and curve together immediately, without a second Apply click. One undo restores the previous setting, rating and any curve edits removed by the selection. A changed device or curve is still refused when the selection was made against old data.

Fault currents on the plot

Every plot labels each bus its devices feed with that bus's fault currents, from the studies of the scenario selected in the header. A shaded band runs from the reduced to the full arcing current, and an arrow marks the bolted fault current; both stop at the same height, and a box names the bus and reads Iarc 3.83–4.37 · Ibf 6.01 kA. Bolted fault current comes from the short-circuit study and the arcing currents from the arc flash study. Values are the bus's own currents at its own voltage; the marks sit where the plot's axis puts them. The arrow marks the bus's total fault current, so a device feeding the bus can carry less when motors or another source also feed it; the Latest study tab gives each device's own current.

Each bus has its own colour. When buses sit close together their marks step down from left to right and their boxes stack beside them. A value from a study that has since gone out of date shows in grey with "stale" after the bus name until you rerun the study. Use Hide fault currents beside the pointer button to hide them; print preview and the PDF follow the same choice.

Useful actions:

• Open selected device on the diagram.
• Add the selected device to the active TCC.
• Start a new TCC from the selected devices.
• Hide or show curves from plot settings.
• Reset a setting to the catalogue default when the control allows it.

5. Undo a part choice

Cmd+Z (Ctrl+Z) undoes a part choice in one step. The previous part comes back with its settings, curve and curve overrides. A curve the edit panel applies straight after a pick is part of the same step. If the device has changed since, Undo says so and leaves it as it is.

Choose TCC label contents

Click the gear button (Configure TCC label defaults) in the catalogue TCC viewer or on a saved project TCC. It opens My TCC label defaults in the catalogue and Plot settings on a project TCC. Select Breaker, Fuse, or Relay, then check the details you want to include. The device's identifying title always remains visible. Missing details produce no empty lines and are marked unavailable in the preview. Breaker function abbreviations use ordered letters, such as LI or LSIG.

Catalogue choices are personal and apply across catalogue devices. Shared project choices apply to all saved TCCs and PDFs in that project. In Plot settings, choose Project shared to edit the project's labels or Personal preview to view the project with your own choices. A personal preview reads "Personal preview — PDF uses project labels"; Print preview always shows the project's shared labels.

TCC defaults are also available in personal Display Config, organization Defaults, project Defaults, and system Defaults settings. Each checkbox shows where its value comes from. Reset removes your explicit choice and restores inheritance. Higher scopes take precedence in this order:

• Catalogue: system → organization → user.
• Shared project drawing and PDF: system → organization → project.
• Personal project preview: system → organization → project → user.

Changing a default updates fields that still inherit it. Explicit project choices remain in place. Only authorized users can edit each shared scope; viewers can still use their own preferences.