1MRK002311-AAr11 Optical medium range line data communication module

Description

Product Overview

1MRK002311-AAr11 is the medium-range build of the line data communication module inside ABB Relion 670 terminals — the ordering table calls it “Optical medium range LDCM”, and the -AA suffix is what distinguishes it from the multimode short-range -AB and the 1550 nm long-range -BA. It plugs into a remote-communication position of a RED670, REG670, REL670, RET670 or REC670 chassis, but its working life is spent differently from a short-haul board: it exists in pairs, in two buildings tens of kilometers apart, and it only functions when both halves agree on framing, clock role and optical level.

The physical interface is single-mode 9/125 µm glass at 1310 nm through FC/PC connectors, with 22 dB of nominal optical budget and a working distance that lands typically between 60 and 80 km depending on the measured route. Launch level is selectable in two steps, receiver sensitivity sits near −30 dBm, and the budget is quoted together with its assumptions — 0.32 dB/km in the fiber, 0.3 dB per FC/PC mating, 0.08 dB per factory splice and a margin held back for transmitter and receiver aging across two to three decades.

What travels over the link has not changed with the distance: every 5 ms a telegram carries three-phase current samples, the time reference that keeps the two terminals aligned, trip and block indications, alarms and eight binary signals for interlocking or transfer trip. On a 70 km span, that cadence makes the channel a synchronous system rather than a message pipe, and the commissioning work is therefore about establishing and documenting a relationship between two sites, not about configuring one card.

Technical Specifications

表格

1MRK002311-AAr11

Key Features and Advantages

One channel, two sites, one commissioning record

The module is only as good as the pair. 1MRK002311-AAr11 at one end has no useful meaning without the corresponding unit, settings and optical level at the other, so commissioning produces a single record covering both stations: launch power and received level at each end, the measured route loss, the power mode chosen and the clock role assigned. That document is what makes a later fault diagnosable, because it contains the reference values for a system nobody can see in one place.

The budget is spent on glass before the first connector

Twenty-two decibels disappears quickly at 0.32 dB/km. A 70 km route consumes around 22.4 dB of fiber alone, which means the margin actually available comes from the difference between a well-surveyed route and a poorly estimated one. Selecting 1MRK002311-AAr11 against an optical time-domain reflectometer survey, rather than against a nominal distance claim, is the only way to know whether the channel has residual margin after two decades of splices and re-terminations.

Clock roles are a decision made twice

One terminal generates the timing and the other derives it from the received signal; a mismatch does not appear as an obvious configuration error but as intermittent channel failure under load. On a two-site scheme the decision must be recorded at both ends and re-verified after any board change, which is why the clock role belongs in the same commissioning document as the optical readings.

A late build in a long-lived channel

Long transmission channels outlive several generations of hardware. An r11 module represents a mature build of a board that has been in service for years, and its practical value is availability: keeping one matched spare for a critical pair avoids a redesign triggered by a single failed card in a station where a like-for-like replacement is the only acceptable repair.

Applications

Inter-substation transmission feeders are the primary case: a 220 kV or 110 kV line whose two ends sit on opposite sides of a river valley, a tie between a generation switchyard and a distant load center, or a crossing of an industrial corridor where no commercial circuit is available. With 1MRK002311-AAr11 in both terminals, the differential function runs on fiber the utility already owns, independent of any multiplexer’s availability.

Regional ties follow the same logic where an operator wants unit protection that does not inherit the failure modes of the SDH layer. Where a multiplexer is used, the LDCM terminates the optical path and C37.94 framing remains end to end, so the protection behaves identically to a dark-fiber scheme.

Hydro cascades with long valley runs link successive REG670 terminals across distances the multimode tier cannot cover, and metro transmission rings apply the board between substations on the perimeter rather than in the same compound. Binary signal transfer schemes specify it whenever the transfer trip has to reach a station beyond a few kilometers — remote trip from external protection, interlocking across a line section, or status exchange for a sequential black-start.

Industrial complexes with widely separated HV nodes complete the picture: a port area with satellite substations, an integrated steel site with outlying distribution, a refinery whose tank farm sits beyond the multimode limit.

Related Products

1MRK002122-AB — short-range LDCM, multimode 62.5/125 µm with ST connectors and 13 dB budget, about 3 km; the tier below this board. 1MRK002311-BA — long-range LDCM at 1550 nm with 26 dB budget, for 110 to 130 km routes; the tier above. 1MRK005500-AA — Ethernet SFP module with optical LC connector for IEC 61850 station bus traffic. 1MRK005500-BA — Ethernet SFP module with RJ45 connector, the copper station-bus alternative. 1MRK002266-EA — optical Ethernet module for station communication on the same IED platform. 1MRK001608-AB / 1MRK001608-BB / 1MRK001608-CB — serial modules for SPA, LON, DNP and IEC 60870-5-103 in plastic, plastic-glass and glass versions. 1MRK002309-AA — galvanic RS485 module for short copper connections inside a station. 1MRK007002-AA — GPS time module, used where the differential function takes its clock from a global reference rather than from the channel. 1MRK002282-AB — IRIG-B synchronization module, the alternative external time base. RED670 / REL670 / REG670 — terminals hosting 1MRK002311-AAr11 in line, distance and generator protection.

Installation and Maintenance

Before installation: obtain a route survey in both directions, since a single-direction measurement can hide a high-loss splice that only shows up when the far end transmits. Confirm the fiber is single-mode 9/125 µm with FC/PC terminations at both stations — a multimode patch cord left in a distribution panel is a common and silent error at this distance. Verify that the free position at each terminal is a remote-communication slot at P30:5, P30:6, P31:3, P32:2 or P32:3, calculate the margin against the 22 dB budget on 1MRK002311-AAr11, and choose the low or high power mode from that result, preferring low unless the route approaches its maximum. Isolate the IEDs before fitting the modules, and coordinate the two stations so both ends are commissioned in the same window.

Maintenance practice: clean FC/PC ferrules at every mating and record launch and received levels at both ends as the baseline. Re-measure annually and after any work at either fiber panel; a shift confined to one end indicates connectors there, while a change at both ends suggests the route itself. After any substitution, restore the channel configuration, confirm the clock roles, run a loop-back test and read the supervision counters before releasing the protection. Hold spare 1MRK002311-AAr11 units as matched pairs where a critical line depends on a single channel, with revision recorded and ports capped.

Warranty and Quality

1MRK002311-AAr11 is supplied as a plug-in module with the revision level printed on the label and repeated in the packing documentation, so each station records which build arrived. Every unit passes a single-mode loop-back verification covering launch power, received level, frame lock and channel status, and the measurement sheet ships with the module. A 12-month warranty applies under standard substation-automation practice, covering repair or replacement for quality-related failures. Because a medium-range scheme always involves two sites, orders for critical lines can be built and dispatched as matched sets, and support covers slot assignment, clock role configuration, budget review from survey data and the low or high power decision.