Description
Key Technical Specifications
| Parameter | Value |
|---|---|
| Manufacturer | ABB |
| Product Family | REF 54x |
| Model | REF545 |
| Full Ordering Code | REF545KB133AAAA |
| Product Type | Feeder Protection and Control Terminal |
| Application | Medium-voltage feeder protection and control |
| Current Inputs | 1 A / 5 A CT configuration |
| Auxiliary Supply | 80–265 VAC/DC |
| Protection Function | Overcurrent protection |
| Earth-Fault Protection | Supported |
| Measurement | Current and electrical network measurements |
| Control | Breaker and feeder control functions, subject to configuration |
| Communication | SPA bus, LON bus, IEC 60870-5-103 |
| Additional Communication | DNP 3.0 / Modbus and other interfaces may depend on installed communication hardware |
| Automation Functions | Programmable logic / feeder control functions |
| Event/Fault Information | Event and fault recording functions |
| Display | Local LCD/operator interface |
| Intended Equipment | MV feeders, switchgear, industrial distribution systems |
ABB’s REF545 belongs to the REF54x family of microprocessor-based feeder protection and control terminals. A technical relay-model database specifically lists REF545KB133AAAA as a REF545 variant.
The exact suffix matters. REF545 units were produced with different hardware configurations, so the complete KB133AAAA ordering code should be preserved when replacing an installed relay. A procurement description such as “REF545 relay” is not precise enough.
Product Introduction
ABB REF545KB133AAAA
The ABB REF545KB133AAAA is a numerical feeder protection and control terminal for medium-voltage electrical distribution systems. It combines protection, measurement, monitoring, breaker control, programmable logic, and substation communication in one feeder-level IED. The REF545 family is documented as a microprocessor-based feeder protection and control platform.
For an operating switchgear lineup, the practical value is integration. One device can handle feeder protection and control functions while exchanging information with the station automation system. The available documentation identifies communications including SPA, LON, and IEC 60870-5-103, with other protocols depending on the installed communication arrangement.
REF545KB133AAAA
Application Scenarios & Field Pitfalls
Engineering Pain Point
A feeder relay replacement rarely ends when the new relay powers up. The real work is making sure CT ratios, protection settings, binary I/O, breaker logic, and SCADA communications reproduce the original behavior. With an older installation, this becomes more important because the exact suffix defines the hardware configuration. Replacing a with a superficially similar variant can leave an otherwise healthy feeder with missing I/O or communication functions.
Typical Applications
- Medium-Voltage Substations — Feeder overcurrent and earth-fault protection with local breaker control.
- Industrial Power Distribution — Protection and measurement of plant MV feeders supplying motors, transformers, and process loads.
- Oil & Gas Facilities — Feeder protection in process-unit and utility substations where relay information is integrated into station automation.
- Power Generation Plants — Auxiliary and distribution feeder protection with event reporting and supervisory communication.
Technical Pitfalls to Avoid
- Do not buy by the family name alone.
The exact code REF545KB133AAAA matters. ABB’s family contains multiple ordering variants, including KB133AAAA, KB133AAAB, KM133AAAA, and others. - Verify CT input configuration.
The available product references identify 1 A / 5 A CT inputs. Confirm the installed relay’s actual CT configuration and the switchgear CT secondary rating before commissioning. Never assume that a 1 A and 5 A application can be treated as interchangeable. - Back up protection settings before replacement.
Record the complete protection parameter set, logic equations, binary I/O assignments, communication settings, and breaker-control logic. A replacement relay that boots correctly can still be incorrectly configured. - Check the communication interface before ordering.
installations may use SPA, LON, IEC 60870-5-103, or other communication arrangements depending on the installed hardware. Do not assume that two units with different suffixes have identical communication hardware. - Treat CT circuits as hazardous.
Never open-circuit an energized CT secondary. During relay replacement, follow the switchgear manufacturer’s isolation procedure and use the designated CT shorting facilities before disconnecting the relay. - Verify breaker-control logic independently.
Binary outputs may be used for trip, close, alarm, interlock, or other functions. Confirm each output against the approved schematic rather than reconnecting wires solely by terminal position. - Expect legacy-system engineering work.
is an older REF54x platform. If the relay is being retained in a brownfield plant, verify engineering-software availability, configuration-file compatibility, communication converters, and spare-part availability before the shutdown begins. The product family is represented in current relay databases as a legacy-generation platform.
Related Products
- ABB REF541 — Lower-end member of the REF54x feeder protection family. It is suitable for feeder protection and control applications with a different hardware and functional configuration. Do not substitute it for without reviewing the protection scheme and I/O requirements.
- ABB REF543 — Another REF54x feeder protection and control terminal. It shares the same general platform family but uses a different configuration and ordering structure. It is relevant when maintaining older REF54x switchgear but is not automatically interchangeable with .
- ABB REF545KB133AAAB — Closely related ordering variant. The final suffix differs from KB133AAAA, so the I/O and hardware configuration must be checked before considering substitution. ABB’s relay-model database lists both variants separately.
- ABB REF545KM133AAAA — Another configuration. It belongs to the same feeder protection platform but has a different hardware code. Treat it as an alternative only after comparing the complete ordering code and installed I/O.
- ABB REF545EM133AAAA — family variant with a different hardware configuration. Useful for legacy replacement evaluation, but not a direct substitute based solely on the common designation.
- ABB REF550 — Feeder protection product in the broader ABB protection portfolio. It is a different platform and should be evaluated as a replacement or modernization option rather than treated as a plug-in substitute.
- ABB REF630 — Relion-family feeder protection and control platform intended for newer protection-system architectures. It can be relevant to a full relay modernization, but replacement requires protection coordination, wiring, I/O, communications, and panel-engineering work.
- ABB REF620 — Relion feeder protection and control relay for distribution applications. It is a newer platform option for applications where the legacy is being phased out. Physical and functional replacement must be engineered rather than assumed.
- ABB SPA-ZC 400 — Communication interface used with compatible ABB SPA-based protection equipment to provide IEC 61850 connectivity. It can be relevant when integrating legacy REF54x equipment into a newer substation communication architecture.
Procurement note: The REF545KB133AAAA is a complete feeder protection and control terminal, not a generic PLC or I/O module. The exact suffix should be copied from the installed nameplate. Before ordering, verify CT secondary rating, auxiliary supply, binary I/O arrangement, communication hardware, protection settings, and the existing configuration file. For a legacy feeder protection system, those details determine whether the replacement is actually suitable.
