Description
Interfacing substation secondary devices with optical communication loops, the ABB SPA-ZC 21 functions as a high-integrity electrical-to-optical bus connection module. It plays a critical role in substation automation by converting electrical signals into optical pulses and vice versa, shielding data links against extreme electromagnetic fields and electrical line interference. The SPA-ZC 21 bus connection module provides direct conversion for TTL or RS 485 signal configurations, connecting protection relays and annunciator units to a centralized fiber-optic network infrastructure. Operating natively within the ABB SPACOM product family, this unit handles data transmission across diverse power system protection and distribution networks.
Features
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High-Isolation Signal Conversion: Seamlessly transforms TTL or RS 485 level signals into light pulses for optical loop transmission.
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Robust Interference Immunity: Offers absolute defense against electromagnetic disturbances and high-voltage transients common in medium and high-voltage substations.
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Dual-Mode Topology Compatibility: Supports dual-mode architecture, allowing field assignment in either master or slave serial communication setups.
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Host-Powered Efficiency: Draws operating power directly from the connected host secondary device, eliminating the need for independent external auxiliary power units.
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Integrated Connector Interfaces: Equipped with a reliable 9-pin D-type subminiature terminal connection for the host device alongside a dedicated optical transceiver pair.
Applications
- Connecting standard secondary substation equipment and protection relays into fiber-optic SPA bus topologies.
- Interfacing utility feeder distribution monitoring networks with centralized substation control levels.
- High-noise industrial power environments requiring complete optical isolation between communication nodes.
Ordering Information
| Type Designation |
Transmitter Type |
Receiver Type |
Order Number |
| SPA-ZC 21BB |
Plastic |
Plastic |
RS 951 021-AA |
| SPA-ZC 21BM |
Plastic |
Glass |
RS 951 021-BA |
| SPA-ZC 21MB |
Glass |
Plastic |
RS 951 021-CA |
| SPA-ZC 21MM |
Glass |
Glass |
RS 951 021-DA |
| SPA-ZC 21BB/S |
Plastic |
Plastic |
RS 951 021-AB |
| SPA-ZC 21BM/S |
Plastic |
Glass |
RS 951 021-BB |
| SPA-ZC 21MB/S |
Glass |
Plastic |
RS 951 021-CB |
| SPA-ZC 21MM/S |
Glass |
Glass |
RS 951 021-DB |
Technical Specifications
| Parameter Category |
Engineered Specification Value |
| Manufacturer |
ABB |
| Part Number / Model |
SPA-ZC 21 |
| Product Series |
SPA Series (SPACOM Product Family) |
| Part Classification |
Original New Part |
| Power Supply Source |
Powered directly from host device via D-connector (no external auxiliary source required) |
| Electrical Interfaces |
TTL level or RS 485 level configuration options |
| Optical Interfaces |
1 pair of optical transceivers (Rx/Tx) |
| Fibre Medium Options |
Plastic (980/1000 micrometers) or Glass (50/125 or 62.5/125 micrometers) fiber cable |
| Operating Modes |
Master or Slave configurable configuration |
| Country of Origin |
Finland (FI) |
Connections and Interfaces
| Connector Interface |
Function / Signal Mapping |
| 9-pin D-type Subminiature Connector |
Host device electrical interface supporting TTL / RS 485 signals and internal power draw |
| Optical Rx Port |
Fibre-optic serial input receiver line for SPA bus signals |
| Optical Tx Port |
Fibre-optic serial output transmitter line for SPA bus signals |
Installation Guidelines
1
Ensure the host protection or annunciator device is powered down completely before securing the 9-pin D-type connector block to avoid erratic interface transitions.
2
Route fiber-optic cables with a generous bend radius to avoid micro-fractures in glass or plastic cores that cause attenuation loops.
3
Clean optical connector tips with approved visual instrument solvents before final insertion into active Rx and Tx ports to guarantee signal continuity.