ABB SPA Bus Modules: SPA-ZC 22 (SPA-ZC22)

Technical Dossier

Product Details And Specifications

ABB SPA Bus Series: Comprehensive Module Range and Technical Overview

The ABB SPA (Serial Protection Automation) bus system is a proprietary fiber-optic serial communication protocol developed by ABB (formerly Asea Brown Boveri) for protection relay coordination and substation automation. Deployed since the late 1980s across heavy industrial sectors — including petrochemical complexes, nuclear power stations, oil refineries, and high-voltage transmission substations — the SPA bus remains one of the most widely installed legacy protection communication architectures in the world. Installations in Europe, Asia-Pacific, and the Middle East continue to operate SPA-based relay networks with operational lifespans exceeding 25–30 years, making spare parts availability a critical infrastructure concern.

The Evolution of SPA Bus Architecture

The SPA bus protocol was introduced by ABB as a master-slave serial communication standard operating over plastic or glass fiber-optic cables at 9.6 kbps. Its primary application was the coordination of protection relays (REF, REL, RET, REB series) with substation control systems such as the SPACOM and later the MicroSCADA platform.

Generation 1 (Late 1980s – Mid 1990s): Initial SPA bus implementations used dedicated SPA-ZC interface cards installed in relay panels. Communication was strictly point-to-point or in a ring topology. Key modules from this era include the SPA-ZC 17 and SPA-ZC 21, designed for RS-232 and fiber-optic bridging respectively.

Generation 2 (Mid 1990s – 2005): ABB expanded the SPA bus ecosystem with multi-port concentrators and PC interface cards. The SPA-ZC 22 was introduced as the standard fiber-optic to RS-232 converter for connecting SPA bus relay networks to SPACOM workstations and MicroSCADA systems. Compatibility with Windows-based SCADA platforms was a key design requirement of this generation.

Generation 3 / Transition Era (2005 – Present): ABB progressively migrated substation communication to IEC 61850 (LON, GOOSE, MMS over Ethernet). The SPA bus was officially classified as a legacy protocol. However, due to the installed base of ABB REF, REL, RET, and REB relays still in service, SPA-ZC interface modules remain in active demand for maintenance, retrofit, and life extension projects. No direct plug-and-play replacement exists for SPA-ZC 22 in legacy panel configurations without relay firmware upgrades.

SPA Bus Full Catalog & Functionalities (SKU List)

The following SKUs represent verified, commonly sourced components within the ABB SPA bus ecosystem. Each module is categorized by functional role.

Bus Interface & Converter Modules

SPA-ZC 17: RS-232 to SPA bus optical interface, early-generation relay panels.
SPA-ZC 21: Fiber-optic SPA bus interface for SPACOM master stations.
SPA-ZC 22 (SPA-ZC22): Fiber-optic to RS-232 converter; standard PC/SCADA interface for SPA bus relay networks.
SPA-ZC 100: SPA bus to LON bus protocol converter for MicroSCADA integration.
SPA-ZC 101: SPA bus to Ethernet gateway module, IEC 61850 migration bridge.
SPA-ZC 102: Multi-port SPA bus concentrator with Ethernet uplink.
SPA-ZC 103: SPA bus optical repeater for extended ring topology distances.

Protection Relay Modules (SPA Bus Native)

REF 541: Feeder protection relay with integrated SPA bus port.
REF 543: Advanced feeder protection relay, dual SPA bus port configuration.
REL 316: Line differential protection relay with SPA bus communication.
RET 316: Transformer protection relay, SPA bus compatible.
REB 103: Busbar protection relay with SPA bus interface.
REF 610: Feeder protection relay, SPA bus and Modbus RTU dual protocol.
REF 615: IED with backward-compatible SPA bus port for legacy integration.
REM 543: Motor protection relay with SPA bus communication module.
REF 630: Feeder protection IED, SPA bus legacy port option.

Power Supply & Auxiliary Modules

SPGU 240A1: Auxiliary power supply unit for SPA bus relay panels, 24–240 V AC/DC input.
SPTO 1D3: Trip output module for SPA bus relay systems.

Sourcing Hard-to-Find & Obsolete SPA Bus Parts

ABB officially discontinued active production of the SPA-ZC 22 and most SPA-ZC series interface modules. Standard ABB distribution channels no longer stock these components. For operators of legacy substation protection systems, this creates a critical supply gap — particularly for utilities and industrial operators under long-term maintenance contracts that prohibit full relay replacement without regulatory re-approval.

DriveKNMS maintains a dedicated inventory of tested SPA bus modules sourced from decommissioned substation panels, authorized surplus channels, and OEM overstock. Our procurement team actively tracks global availability of SPA-ZC 22, SPA-ZC 21, SPA-ZC 100, and related interface hardware. For operators requiring long-term supply agreements or buffer stock arrangements for SPA bus components, DriveKNMS provides documented sourcing traceability and condition reports for each unit.

Quality Control for the SPA Bus Module Range

SPA bus interface modules such as the SPA-ZC 22 incorporate fiber-optic transceivers, RS-232 UART controllers, and optically isolated signal conditioning circuits. Standard visual inspection and power-on testing are insufficient to verify communication integrity for these components.

DriveKNMS applies the following test protocol to all SPA bus modules prior to dispatch:

Fiber-Optic Transceiver Verification: Optical power output measured at 660 nm wavelength against ABB factory specification (typically –15 dBm to –10 dBm). Receiver sensitivity threshold confirmed using calibrated optical attenuator.
RS-232 Signal Integrity Test: Full loopback test at 9.6 kbps, 19.2 kbps, and 38.4 kbps baud rates. Voltage levels verified per EIA-232 standard (±5 V minimum swing).
SPA Protocol Frame Test: Live SPA bus frame transmission and acknowledgment test using ABB SPACOM emulation software. Confirms correct framing, CRC, and address decoding.
Isolation Test: Optical isolation between fiber and RS-232 circuits verified at 500 V DC for 60 seconds.
Thermal Cycling: Modules operated at 0°C and 55°C for 30-minute intervals to screen for cold-solder and thermal-drift failures.

Each unit ships with a test report documenting pass/fail results for all five test stages.