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The ABB REF 545 REF545KB133AAAA Machine Protection Terminal is a protection and control device for electrical power system applications. It belongs to ABB’s REF 545 family and is used to monitor electrical operating conditions, identify abnormal states, and initiate appropriate protection or control actions within a substation or industrial power distribution system.
In a typical protection scheme, the terminal receives measurement and status information from the electrical network through current and voltage transformers, together with binary information from circuit breakers and other switching equipment. The protection functions evaluate these signals against configured operating criteria and determine whether a trip, alarm, or control response is required.
The terminal can be incorporated into protection and control panels where dependable monitoring of feeders, switchgear, and associated electrical equipment is required. It can also exchange operational information with higher-level automation or supervisory systems, allowing protection events and equipment status to be incorporated into the wider substation control architecture.
For replacement projects, the complete REF545KB133AAAA ordering code should be matched with the existing protection scheme, measurement inputs, communication arrangement, control logic, and configured protection functions. Particular attention should be given to the existing relay settings and external wiring before commissioning.
| Parameter | Specification |
|---|---|
| Model | REF 545 |
| Order Number | REF545KB133AAAA |
| Product Family | REF 545 |
| Product Type | Machine Protection Terminal |
| Manufacturer | ABB |
| Primary Function | Electrical protection and control |
| System Role | Protection, monitoring, and control terminal |
| Typical Application | Power system and industrial electrical protection |
| Dimensions | 265.9 × 223.7 × 235 mm |
| Weight | 8 kg |
The terminal receives electrical measurements and equipment status signals from the protected installation. Current and voltage information, together with breaker and switchgear status, is processed by the protection logic configured in the terminal.
CT / VT Measurements + Switchgear Status → REF 545 → Protection Logic → Trip / Alarm / Control Command
Under normal conditions, the terminal continuously evaluates incoming measurements and equipment states. When an electrical quantity or equipment condition meets a configured protection criterion, the corresponding protection function identifies the abnormal condition.
The terminal can then initiate the appropriate response through its output and control interfaces. Depending on the protection scheme, this may involve issuing a breaker trip command, generating an alarm, or communicating the event to a higher-level control system.
This arrangement allows protection decisions to be made locally at the electrical installation while maintaining communication with the broader substation or plant automation system.
The REF 545 REF545KB133AAAA operates at the protection and control layer between electrical measurement equipment and switching devices. It processes information from the power network and coordinates protection responses with circuit breakers and supervisory systems.
Power Network → CT / VT → REF 545 → Protection Decision → Circuit Breaker / Alarm → Power System
| System Element | Function |
|---|---|
| Current Transformers | Provide current measurements from the protected circuit |
| Voltage Transformers | Provide voltage information where required by the protection scheme |
| REF 545 | Processes measurements and executes configured protection logic |
| Circuit Breaker | Interrupts the protected circuit following a trip command |
| Switchgear | Performs electrical switching and isolation functions |
| Station Control System | Monitors protection and equipment status |
| HMI / SCADA | Provides operator visualization and supervisory control |
| Application | Typical Use |
|---|---|
| Electrical Substations | Protection and control of power system equipment |
| Industrial Power Distribution | Monitoring and protection of electrical feeders and switchgear |
| Manufacturing Plants | Protection of plant electrical infrastructure |
| Power Generation Facilities | Electrical protection and operational monitoring |
| Process Plants | Protection and control of critical power distribution equipment |
| Switchgear Systems | Integration of protection, measurement, and breaker control |
| Component | Function |
|---|---|
| Current Transformer | Supplies current measurement to the protection terminal |
| Voltage Transformer | Supplies voltage measurement where required |
| Circuit Breaker | Interrupts the electrical circuit following protection operation |
| Switchgear | Provides switching and isolation of electrical equipment |
| Protection Test Equipment | Used to verify configured protection functions |
| Station Control System | Collects protection and equipment information |
| SCADA System | Provides supervisory monitoring and event management |
| Communication Network | Transfers protection and operational data |
| Model / Product Family | Product Type | Typical Application |
|---|---|---|
| ABB REF 545 | Machine Protection Terminal | Electrical protection and control |
| ABB REF 54x Series | Protection and Control Terminal | Substation and industrial power systems |
| ABB REF 541 | Protection and Control Terminal | Feeder and electrical equipment protection |
| ABB REF 543 | Protection and Control Terminal | Substation protection and control |
| ABB REF 545 | Protection and Control Terminal | Machine and electrical system protection |
| ABB Relion Protection Family | Protection and Control Relay | Modern power system protection |
| ABB Current Transformers | Measurement Component | Current acquisition for protection |
| ABB Voltage Transformers | Measurement Component | Voltage acquisition for protection |
The protection scheme may include current and voltage measurements together with binary signals representing circuit breaker, disconnector, alarm, or equipment status. The exact signal arrangement depends on the configured protection application.
Incorrect CT wiring can affect the magnitude or phase relationship of measured current and may cause incorrect protection behavior. CT polarity, phase assignment, secondary connections, and applicable test procedures should therefore be verified before the protected equipment is energized.
Check the configured protection function, pickup settings, output mapping, trip circuit wiring, breaker interface, and blocking or interlocking conditions. The protection decision and the physical trip path should be tested separately to identify where the response is being interrupted.
The existing protection settings, configured functions, I/O assignments, communication parameters, and relevant event or commissioning records should be preserved where applicable. A replacement terminal should be commissioned against the documented protection scheme rather than relying only on the physical wiring.