ABB Pre-configured Matching Unit (PCMU) Protection and control

Protection and control

The PCMU MSOC is the most powerful, advanced and simplest

feeder protection relay in its class, offering time and instantane

ous overcurrent, negative sequence overcurrent, phase discon

tinuity, breaker failure, thermal overload, and voltage metering

and protection. The relay features optional high impedance fault

(HIZ) and sensitive earth fault (SEF) protection for grounded and

ungrounded distribution systems. The relay incorporates a flexi

ble three-phase multi-shot auto-reclose function for automatic

feeder restoration in temporary faults on overhead lines.

The PCMU MSOC integrates basic control functionality, which

facilitates the control of one circuit breaker via the relay’s front

panel human machine interface (HMI) or remote control system.

To protect the relay from unauthorized access and to maintain

the integrity of information, the relay has been provided with a

four-level, role-based user authentication system, with individual

passwords for the viewer, operator, engineer, and administrator

levels. The access control system applies to the front panel

HMI, embedded web browser based HMI, and the PCM600

relay setting and configuration tool.

Standardized communication

As a standard feature, PCMU MSOC supports the IEC 61850

standard for communication between devices within the subs

tations along with the industry standards DNP 3.0 and Modbus

protocols. The implementation of the IEC 61850 substation

communication standard in PCMU MSOC encompasses both

vertical and horizontal communication, including GOOSE mes

saging and parameter setting according to IEC 61850-8-1. The

substation configuration language enables the use of enginee

ring tools for automated configuration, commissioning, and

maintenance of substation devices.

Pre-emptive condition monitoring

For continuous knowledge of the operational availability of the

PCMU MSOC features, a comprehensive set of monitoring

functions to supervise the relay health, the trip circuit, and the

circuit breaker health is included. The breaker monitoring can

include checking the wear and tear of the circuit breaker, the

spring charging time of the breaker operating mechanism and

the gas pressure of the breaker chambers. The relay also mo

nitors the breaker travel time and the number of circuit breaker

operations to provide basic information for scheduling breaker

maintenance.

Bus protection via GOOSE

The IEC 61850 implementation in PCMU MSOC includes

fast peer-to-peer communication, over the substation bus.

Use GOOSE communication between PCMU MSOC relays of

the incoming and outgoing feeders of a substation to form a

stable, reliable, and high-speed busbar protection system. The

cost-effective GOOSE-based busbar protection is obtained by

configuring the relays and the operational availability of the pro

tection is assured by continuous supervision of the protection

devices and their GOOSE messaging over the station bus. No

separate hard-wiring is needed for the horizontal communica

tion between the switchgear cubicles.