Set up and arm LOMAC

Scope

This guide explains how an installer commissions LOMAC on one load bus: prerequisites, settings, dry run, arming and a test transfer. Read How LOMAC works and How plant control works first. LOMAC statuses and settings field definitions defines every status and setting.

Location

• Settings: the LOMAC tab in the settings dialog of each point, on the Diagram tab of the Plant Control System page.
• Status and plan: the LOMAC dialog, from the three-dot menu on the plant control card.

Permissions

• Viewer and higher: can read the LOMAC dialog and the LOMAC tabs.
• Editor or higher, with the advanced role: can do every step in this guide.

Step 1: Prerequisites

An interlocked grid switch cannot connect the grid to a bus a converter is forming, by its own mechanical or hardwired design. Examples: a changeover switch that cannot close both sides, or two contactors wired so that each one's auxiliary contact breaks the other's coil circuit.

• Supported converter: the Megarevo MEGA. Any other converter shows MODE_UNSUPPORTED and cannot join a forming level.

The bus needs a separate grid switch when:

• a converter on the bus does not disconnect itself from the grid
• only some of the converters on the bus form it
• the grid-side position must come from a contact independent of the converter

Step 2: Single-Line Diagram

LOMAC reads the single-line diagram on the Diagram tab. It finds the switches between the load and the grid, and the converters that feed the load bus. See Add and connect devices in plant control.

1. Make sure that the grid point, the load point and every converter on the bus are on the diagram.
2. Add each grid-side switch as its own AC Control Switch or AC Control ATS point, on the line between the grid and the load.
3. Make sure that every line on the diagram matches a cable on site.

Step 3: LoggerV IO Outputs

LOMAC operates switches only through the LoggerV IO service. The setting applies to the whole gateway, so it changes how every plant control relay on the LoggerV is driven.

1. On the Diagram tab, turn on Edit and double-click the load point.
2. On its LOMAC tab, find the LoggerV IO outputs card and click Enable.
3. Click Enable in the confirmation.
4. Reload the page.
5. Restart the LoggerV.

Step 4: Switch Feedback

LOMAC operates only a switch whose position it can read. Wire an auxiliary contact on each switch to a LoggerV input, on a different point from the output that drives the switch.

1. Double-click the switch. On an AC Control Switch, set Output ID: on the Basic tab to the output that drives it.
2. On its LOMAC tab, set LOMAC Enabled: to Enabled. LOMAC is then the only writer to that output.
3. Set Feedback Input: to the input the auxiliary contact is wired to.
4. Set Feedback Polarity: to Straight for a normally-open contact, or Reversed for a normally-closed contact.
5. On an AC Control ATS, set Transfer Output:, Output Polarity and Input 1 Feedback instead of Output ID. Input 2 Feedback is optional.
6. Operate the switch once, and make sure that its Position in the LOMAC dialog follows it.

A switch with no feedback input shows UNVERIFIED, and LOMAC does not command it.

Step 5: Converters

On the LOMAC tab of each converter on the bus:

1. Set LOMAC Enabled: to Enabled.
2. Set Forming Level:. Give two converters the same number only if they are wired to run in parallel.
3. Set Forming Mode: to the mode the converter forms the bus in.
4. Set Enter Off-grid Above: above the Leave Off-grid Below value.
5. Set Leave Off-grid Below: below the Enter Off-grid Above value.
6. Leave Off-grid Permit at Permitted, or make it a rule list (see Build a rule list).

If a converter with LOMAC support stays at LOMAC Enabled Disabled, its island cannot go off grid unless a LOMAC switch cuts it off. The converter also needs its battery bound through Storage Cluster ID on its Basic tab, or it shows SOC_MISSING.

Step 6: Load Point

On the LOMAC tab of the load point:

1. Set LOMAC Profile to On-grid priority or Off-grid priority.
2. If two or more load points on the same bus have a profile, set Primary For This Bus: to Primary on exactly one of them.
3. Leave Dry Run: at Dry run.

Step 7: Dry Run Check

In dry run LOMAC evaluates the bus and publishes a plan, and commands nothing.

1. Open the LOMAC dialog from the three-dot menu on the plant control card. The Status tab shows DRY RUN: LOMAC monitors and makes plans only. An abort that started in live mode can still complete.
2. On the Status tab, make sure that the forming level you expect is eligible and selected, and that its Blockers column is empty.
3. Make sure that the Why LOMAC does not act card shows no warning.

Step 8: Arming

1. On the LOMAC tab of the load point, set Dry Run: to Armed.
2. Click Save.
3. Make sure that the Status tab shows ARMED: LOMAC can transfer the load. The load has no supply during a transfer.

Step 9: Test Transfer

Do this test in a planned window with site staff present.

1. Open the grid supply to the site by hand.
2. On the Timeline tab, make sure that the transfer runs through its steps and a converter forms the bus.
3. Restore the grid supply, and make sure that the load returns to the grid.

During a transfer, the plant control page shows LOMAC transfer in progress. Do not change plant settings. If a transfer stops, the Timeline tab shows the step it stopped at.

Troubleshooting

• LOMAC blocked: IO service outputs off, switch positions unverifiable; enable IO service outputs: the LoggerV IO outputs are off. Do step 3.
• LOMAC blocked: [switch] position unverified, wire its feedback input: the switch has no feedback input. Do step 4.
• LOMAC blocked: 2 points with a profile, 0 flagged primary, need exactly 1: [points]: set Primary For This Bus to Primary on exactly one of the named load points.
• off-grid blocked: [converters] on the island, not LOMAC-enabled: set LOMAC Enabled to Enabled on the named converter, or cut it off with a LOMAC switch.
• MODE_UNSUPPORTED in the converter table: the driver of the converter does not support LOMAC. The converter cannot form the bus.
• SOC_MISSING in the converter table: no battery is bound to the converter. Set Storage Cluster ID.
• LOMAC [point] fault latched: reset required: transfers aborted too many times in a row. Find the cause on the Timeline tab, then click Reset fault.
• Not saved: Permission denied! Required permission [advanced] to change: [settings]. beside Save: the account does not have the advanced role. The dialog stays open. Undo the named changes, or ask a user with the advanced role.

Tips and Gotchas

• A latched fault stays after a LoggerV restart. Fix the cause, then click Reset fault.
• Disabled (holds position) stops LOMAC, and the bus stays where it is. Off grid, the load does not return to the grid by itself.
• Keep the timing settings on the LOMAC tab of the load point at their defaults, unless support asks for a change.