Relay Engineering Services PCA2 Data Sheet

Relay Engineering Services Limited

Fax: [phone] E-mail: [e-mail] www.davis.com

Overview

System Concept

On-Load Current Injection

Current Output

Multichannel Current/Voltage/Contact-Event Recorder

www.relayeng.com

Power Systems Protection Test Equipment

PCA2 On-Load Protection Condition Analyser

• Tests entire system (Relay, Breaker,

Tripping Supply, Wiring etc.)
simultaneously

• Records full protection operati on

sequence (before, during and after
fault/trip/reclose)

• Captures critical ‘fir st t r i p’

• On or Off-Load Injection Test Set/Timer

• On or Off-Load Breaker Analyser

• General Purpose Oscillographic/Event

Recorder with COMTRADE export

• Quick PC data transfer via USB drive

Developed in conjunction with EDF Energy UK, the PCA2 is a complete
substation protection performance evaluati on and recording system. It tests
several elements of the protection system. Its advanced software-controlled
current source can inject a precise current into the relay even while the system
is on-load. The critical “first-trip” of both relay and breaker can then be
captured and automatically analysed.

It is well-known that some relays and breakers can become sluggish after a
long period of inactivity. The ideal way to test any protection system is to
simulate the precise conditions that occur during a fault on a previously
undisturbed system while simultaneously recording its performance.
Performing such a tes t on a system that has not operated for a long tim e then
yields very useful data as to how the system would perform given a real fault.

Traditionally the different protection system parts (relay, breaker, tripping
supply, etc.) have been tested individual ly with the circuit first being taken off­line manually. Modern maintenance strategies call for efficient and mi nimally
intrusive methods that can provide a computerised record of the performanc e
of the entire protection as a complete system and with the least outage time.

The PCA2 also records the tripping supply and trip-coil current profile and
additional voltages/contacts/currents as desired. The unit automatically
analyses this information to extract data on many aspects of breaker and
overall protection system condition. As well as performing a complete system
test, the PCA2 can be used for testing overcurrent relays and breakers
individually and for many other investigative studies on protection systems,
both on- and off-load. The PCA2 is a key tool that enables a truly cost-effective
Reliability Centred Maintenance (RCM) program for substation protection.

Basic & Optional Connections for ON-LOAD testing

625 East Bunker Court Vernon Hills, IL 60061-1844 Toll-free: 800-358-5525

The PCA2 incorporates an advanced current injection unit together with a
deep-memory high-resolution multichannel current/voltage/contact-event
recorder. Both injection and recording functions can be used together or totally

independently.

All instrument control is via a bright high-resolution colour touch-screen. The
built-in printer provides an instant hard-copy printout. The USB port enabl es
quick and convenient results transfer to a PC via “pen drives” as well as the
use of a Bar Code Reader for quick site data entry.

The advanced current output of the PC A2 can function in one of two modes:
as a general-purpose precision injection unit for off-line relay testing or as a
special ON-LOAD injection unit. W hen used for on-load injection, an external
clip-on Hall-effect CT is used to record the load current & establish main
contact time, and as a feedback element so that a precise and stable c urrent
can be injected into the relay, compensating for any load current present.

The current output of the PCA2 employs fully digital waveform generation &
low-noise switching amplifier technology. The processor generates high
precision waveforms to the required amplitude, frequency and phase angle.
The output is continuously monitored and tightly regulated, maintaining an
accurate, ultra-low distortion waveform independent of the supply input or
load. This guarantees clean sinusoidal waveforms are produced, even into
difficult saturating magnetic loads (i.e. electromagnetic relays). If the output
deviates from its programmed setting for any reason (open circuit, overburden,
etc.) then the operator is warned via a message on the display.

The PCA2 is also a fully fledged high-speed oscillographic recorder with 80Mb
of memory dedicated to high-speed/high-resolution recording of the various
current/voltage/contact input channels. Several start/stop external triggering
and event capture modes are available.
As well as providing instant hard-copy printout of measurements of waveforms
and relay/breaker timing data, the PCA2 can save the raw recorded
oscillographic data to internal mem ory or the supplied USB memory stick for
transfer to a PC. The industry standard COMTRADE file format (IEEE
Standard Common Format for Transient D ata Exchange for Power Systems)
is used.
The standard PCA2 configuration provides for 2x Current and 4x
Voltage/Contact channels. Each V oltage/Contact input can also be used with
transducers/low-level signals or for recording extra currents (using additional
clip-on current probes). The Voltage/Contact channels can also connect
directly across offline breaker main contacts for additional timing
measurements (pole-slip, etc.)