gard 8000 system

• One product for all your teleprotection and line pro-tection needs.

• Proven, high-speed, secure and reliable synchronouscommunications.

• Use as a stand-alone teleprotection channel, line dif-ferential protection, distance relay, Power Line Car-rier, or combine them in one device.

• Use 6U version for up to 8 functions, 3U version forup to 3 functions.

• Selectable redundancy for power supply, main pro-cessor, functional modules and comms interfaces.

• Customized programmable logic for your specificapplication saves commissioning time and eliminatescomplex configuration.

• Straightforward web browser user interface for set-tings and diagnostics; no proprietary application pro-gram required.

• Optional, built-in GPS receiver provides accurate timetags, independently from any station clock.

RFL Electronics Inc. (August 2004) GARD 8000

Protective Relay and Communications System

GARD 8000System

Global Architecture Relaying Device

• Efficient use of your communications channel; up to12 x 64 kbps per fiber or connection.

• Up to 10 communication interfaces in one 6U de-vice; use for redundant communication paths or todifferent remote terminals.

• A wide range of communication interfaces to choosefrom:

• T1/E1• RS-449, 56 -768 kbps• X.21, 64-768 kbps• V.35, 64-768 kbps• G.703, co-directional, 64 kbps• ANSI C37.94 fiber• Fiber, multi-mode or single-mode; up to 80 km• Audio Tone, 2 wire or 4 wire• Power Line Carrier; ON/OFF or FSK selectable

• The communication interfaces can be freely mixed-and-matched; e.g. use a 64 kbps digital channel asprimary and a leased phone line for back-up.

Proper performance of the Protection System requires afunctioning communication link and teleprotection device.While protective relays are commonly duplicated for in-creased redundancy, this is not always the case for the com-munications channel. Limited availability of external com-munication links, or the cost of adding a second channelcompromises power system protection redundancy.

Figure 1. Protection System

Figure 2. Hardware Redundancy

With the exponential growth of data communications, theuse of a dedicated fiber for a single channel, low-speeddata, might no longer be justified. The GARD 8000 systemuses the communication channel efficiently and can pro-vide up to 768 kbps on one link (twelve 64 kbps channels).

The GARD 8000 System offers interfaces for dedicated fi-ber and direct connection to T1/E1 or SONET/SDH

The telecommincations industry has very stringent require-ments for redundancy. The principle of “no single point offailure” is adopted. With the increased demands on thepower system, hardware redundancy in the protectiondevice provides an added level of insurance. GARD 8000can be equipped with redundant power supplies, redun-dant main processors, redundant input/outputs, redundantfunctional modules and redundant communication inter-faces providing an unequaled safe-guard against equip-ment failures.

System protection redundancy can be improved by theGARD 8000 System. Not only can additional channels eas-ily be made available but the built-in hardware redundancywill provide a higher degree of dependability than two sepa-rate protection systems. In addition, external relay-to-tele-protection wiring is eliminated, minimizing the risk of faultyconnections affecting the protection system.


Protection System

GARD 8000 System

Figure 3. System Block Diagram

Hardware Redundancy Economical Use of Your Com-munication Link

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It has been shown that redundancy is increased by built-in redundant modules, operating in parallel. A typical,coventional, protection system would consist of a Main 1pilot protection scheme and a Main 2 pilot or non-pilotscheme. Industry papers have suggested that the improve-ment of unavailability for a dual channel pilot scheme ascompared to a single channel is in the order of 30%. Add-ing a channel to a Main 2 non-pilot relay improves avail-ability even more.

Figure 5. Alternative Redundant Configuration


Functional Redundancy

Figure 4. Parallel, Redundant Configuration

muliplexers. For applications where no digital channelsare available, the audio tone interfaces can be used for 2wire or 4 wire FSK communications. In addition, GARD8000 can be equipped with an integral Power Line Carrier,selectable ON/OFF or FSK operation (available April 2005.)

The GARD 8000 System provides 24 channels, each carrying 64kbps data. These channels can be assigned to any communi-cations interface and operate redundantly or independently.

The GARD 8000 System is easily customized to meet theredundancy requirements for a specific application. A func-tional module can be selected to operate independently,using its own communications interface and input/outputmodules. Or, several functional modules can use the samecommunication interfaces and input/output modules.

Even though providing this extended flexibility and func-tionality, the GARD 8000 System is designed based onproven teleprotection and relaying principles. There is nocompromise on speed, security or dependability. Typicaltransfer trip speeds over digital channels are 5 ms, usingthe most secure mode.

The GARD 8000 offers full flexibility to use multiple commu-nication interfaces for Main 1 and Main 2 relay protections.Both protections can communicate over both channels orthey can use separate channels. You may also achieveredundancy by using one interface with multiple channelswhen digital media is available. Or, use one digital commu-nications interface for more data demanding protections suchas current differential and a second, independent, analogchannel for distance pilot and/or transfer trip functions.

Dedicated fiber links can be routed via the GARD 8000 Systemmaking up to 11 additional 64 kbps channels available on theexisting optical fiber. These channels can be used for proven,secure and dependable transfer trip; high speed pilot communi-cations; current differential and/or distance protections.

Optimize Existing FiberApplications

Figure 6. Dedicated Fiber Application

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The cost for external communication channels is high andit might be difficult to justify the use of an additional fiberpair or installation of additional communication devicesfor protective relaying. By use of the pass-through capabil-ity in GARD 8000, full channel redundancy can easily beachieved on a single fiber pair that has an alternative pathbetween the relay devices.

The GARD 8000 System can pass the data from one chan-nel on one communications interface directly to anotherchannel on another communications interface. The maxi-mum through-delay for this operation is less than 250 mi-croseconds. Data communication remains synchronous dur-ing the pass-through process and can be used for currentdifferential relay channels and teleprotection channels aswell as other relaying channels.

Figure 7. Pass-through functionality

Figure 8. Double circuit line application

The same type of arrangement can be made on any circuitthat has alternative communication possibilities betweentwo line terminals. The example in Figure 9 shows a threeterminal line where only one single fiber pair is used be-tween each substation. In the same way as for the doublecircuit line, full channel redundancy is accomplished byuse of the pass-through ability of GARD 8000.

Figure 9. Three terminal application

The multiple channel ability in the GARD 8000 System op-timizes use of the communication media and offers simplemeans to improve system reliability and availability.

As an example, for a double circuit line, the two parallelcommunication links can be utilized to achieve full com-munications channel redundancy. The use of a communi-cation link between the GARD 8000 systems in each end ofthe double circuit line enables two different paths, or sepa-rate communications channels, to the remote terminals.

As shown in Figure 8, each terminal has two communicationpaths to the remote end; a message from A to B is both sentdirectly on the fiber between A and B and passed-through C andD to B. In case the link between A and B is non-functional, A willstill be able to send messages to B and vice versa.

No change to the existing scheme is required. A protectionusing low-speed RS-232 communication or current differ-ential relays using 56/64 kbps over fiber will still have theuse of a functionally dedicated point-to-point connection.


Cost-Effective ChannelRedundancy

MultipleCommunication Paths

Optimize Existing FiberApplications (Cont.)

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The GARD 8000 system can be equipped with up to eight(three for 3U version) functional modules.

• Full featured teleprotection channel• High speed current differential line protection, charge

comparison• High speed pilot or stepped distance protection• ON/OFF and FSK Power Line Carrier• Digital Fault Recorder module

All modules independently provide full functionality andcan be freely combined to suit your application.

The GARD 8000 is a modular system and functional mod-ules can be added at any time as needed. This facilitatesgradual refurbishment. For instance, the teleprotection chan-nel device can be replaced with GARD 8000 using existingrelays for pilot protection. At some later time a protectionmodule can be added to replace or complement the exist-ing relays. Or, communications modules can be added asmore external channels become available.

The functional modules are truly individual devices. They allneed access to the power supply and the HMI/main pro-cessor modules but there is no direct communication be-tween functional modules. This makes it easy to change thefunctionality of the GARD 8000 as required without havingto change the entire system. Any of the functional modulescan be removed at any time (even without powering off thesystem) without affecting the other functional modules.

A functional module can be located anywhere within a chas-sis, with the exception of the 3 fixed slots required for the HMI/main processor boards. In this way, a system can containany combination of functions, with selectable redundancy.

Input and output boards are also freely selectable, and anadditional board is easily installed in the field if extra con-tacts are required.

The modular flexibility extends to the communications modulesthat may be selected to operate independently or redundantly.

Figure 11. 6U Rear View (example configuration)

Figure 12. 3U Front View (example configuration)

Architecture A Truly Modular System

Figure 10. 6U Front View (example configuration)

Figure 13. 3U Rear View (example configuration)

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Protection system reliability may be compromised by in-creased complexity of protection devices. While these pro-tection devices offer added flexibility they also increase therisk for errors. Complicated settings, configurations andinterconnections all combine to having an undesirable ef-fect on protection system security and dependability.

The GARD 8000 System is designed with ease-of-use in mind.While high functionality and great detail is provided, it is notnecessary to make field configurations, if not desired. Theweb browser User Interface makes interaction with the devicehighly intuitive and handling greatly simplified.

Two rows of ten multi-colored LED’s provides basic eventinformation. The LED operation is fully configurable andlabels can be changed to suit the application. Custom con-figuration and labeling can be factory-made by RFL with-out extra charge. Any field modifications required are sim-ply made by use of the browser interface.

Figure 15. GARD 8000 3U Front Panel

Figure 16. Front Display/PDA*

* Typical PDA is shown. PDA supplied as part of the GARD 8000 System is subject to change.


User Interface

Front Panel Display

Front Panel LED’s

An optional front panel display is available for metering,targets and settings. The front panel is making use of astandard PDA (Personal Digital Assistant) running a webbrowser application.

Figure 14. GARD 8000 Front Panel

All interaction with the GARD 8000 System is made by theuse of a standard web browser. The web server reside in thedevice; no special application software is required on the PC.

A PC is connected to the front TCP/IP port with a standard RJ45connector. Alternatively, the front (or rear) RS-232 port can beused but will not provide the same “lightning-fast” response.

Web browser technology provides a much higher level ofease-of-use as compared to the conventional “menu-driven”operation. It is fast and simple to view device status, accessdiagnostic and test functions and to change settings. Withthe same operations as a standard web site, navigation is

Web Browser User Interface

The GARD 8000 front panel has two infrared ports whenthe PDA is supplied permanently mounted on the front.One communicates with the front PDA and the other isavailable for any external PDA the user may carry. Com-munication may be established with any PDA or pocketPC via its browser application.

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Figure 18. Ethernet Connector

Figure 17. Web Browser User Interface

Input and Output ModulesThe GARD 8000 System is configured with a selectablenumber of input and output modules on the rear part ofthe chassis. Each communication interface comes withone input module with 6 opto-isolated inputs or one out-put module. Solid-state outputs, relay outputs and addi-tional inputs are mounted in sets of 6, with two sets oneach board occupying one slot. The following combina-tions are available for mounting in the up to 10 rear slots(6U) or 4 rear slots (3U):

intuitive and eliminates the need to study written instruc-tions. If needed, the instruction manual, that also resides inthe device, is simply accessed by the HELP function.

For off-line preparation of settings and configuration files,a small application program “emulating” a GARD 8000 Sys-tem can reside on the PC or local server. Archiving anddocumentation of settings and configuration is made simpleas these are stored in standard text files.

Up to 8 setting groups are available. A group does notonly contain settings but all configuration, output and in-put mapping and labels as well. Input contacts and/or HMIcommands can be used for group switching.

• 1 communication interface/6 inputs• 1 communication interface/6 outputs• 6 inputs/6 inputs• 6 inputs/6 relay outputs• 6 inputs/6 solid state outputs• 6 solid state outputs/6 solid state outputs• 6 solid state outputs/6 relay outputs• 6 relay outputs/6 relay outputs

All relay output contacts are Form A (NO) or Form B (NC)jumper selectable. Solid-state outputs are Form A. Inputsand outputs can be inverted in the system logic anddebounce, and drop-out delay timer settings can be applied.

The GARD 8000 Power Supply is provided with Form C alarmcontacts for power supply failure and system failure alarm.

Optically Isolated InputsQuant i ty :Quant i ty :Quant i ty :Quant i ty :Quant i ty : 6 per moduleInput Voltage Jumper Selectable:Input Voltage Jumper Selectable:Input Voltage Jumper Selectable:Input Voltage Jumper Selectable:Input Voltage Jumper Selectable:

24/48/125/250 VdcOperation RangeOperation RangeOperation RangeOperation RangeOperation Range:

24 Volts: 19 to 36 Vdc48 Volts: 37 to 68 Vdc125 Volts: 94 to 150 Vdc250 Volts: 189to 300 Vdc

Input Current:Input Current:Input Current:Input Current:Input Current:1.5 mA minimum

Minimum Pulse Width:Minimum Pulse Width:Minimum Pulse Width:Minimum Pulse Width:Minimum Pulse Width:0.03 ms, additional debounce time set in the logic

Solid-State OutputsQuant i ty :Quant i ty :Quant i ty :Quant i ty :Quant i ty : 6 per moduleOutput Current:Output Current:Output Current:Output Current:Output Current:

Maximum 1 A continuous, 2 A for one minute, or10 A for 100 msec

Open-Circuit Voltage:Open-Circuit Voltage:Open-Circuit Voltage:Open-Circuit Voltage:Open-Circuit Voltage:300 Vdc maximum

Pick-up Time:Pick-up Time:Pick-up Time:Pick-up Time:Pick-up Time: 0 msec

Relay OutputQuant i ty :Quant i ty :Quant i ty :Quant i ty :Quant i ty : 6 per moduleRelay Pick-up Time:Relay Pick-up Time:Relay Pick-up Time:Relay Pick-up Time:Relay Pick-up Time: 4 msecOutput Current Rating:Output Current Rating:Output Current Rating:Output Current Rating:Output Current Rating: 6 A continuousSurge:Surge:Surge:Surge:Surge: 30 A for 200 msec

Alarm RelaysQuant i ty :Quant i ty :Quant i ty :Quant i ty :Quant i ty : 2Contacts:Contacts:Contacts:Contacts:Contacts: SPDT (Form C)Output Current:Output Current:Output Current:Output Current:Output Current: 100 mA 300 Vdc resistive load

Terminal ConnectionsScrew terminals for ring lugs with wire up to AWG #10.

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GPS ModuleAccurate time stamping is essential for evaluation of protec-tion system operations, especially following a major systemdisturbance.

The substation may be equipped with a GPS central clockthat can be connected to the GARD 8000 IRIG-B port. Whena central clock is not available, or to provide an independenttime source, the GARD 8000 can have its own, built-in GPSreceiver. This module is supplied with a small antenna to bemounted outside to receive the GPS signal.

When the GARD 8000 is equipped with the internal GPS re-ceiver, the IRIG-B port can be used to supply IRIG-B to otherdevices. This enables not only the GARD 8000 System tokeep accurate time tags but other protective devices also haveaccess to a dc-powered, substation hardened, time sourcethat is independent from any centralized GPS system.

Figure 19. GPS Antenna

Teleprotection System

GARD 8000Feature Summary

Based on the RFL 9745 teleprotection channel, the GARD8000 Teleprotection System carries relaying communica-tions to the next level.

The Teleprotection System is emulating RFL 9745’s flexible,customized programmable logic but provides a higher de-gree of ease-of-use. Selection of pre-programmed schemesfor blocking, unblocking, permissive and transfer trip op-erations is simply done by a setting.

The GARD 8000 System is customized to provide the numberof channels, type and number of channel interfaces, inputsand outputs and redundancy to meet your application needs.Features include:

• 4 to 32 commands per digital interface• Settable input debounce and continuation timers• Selectable security count• Operating time is 5 ms for digital channel and from 9 ms

for analog channel• 2 or 4 commands per analog channel interface• An analog channel can be used with V.29 modem for

coded transfer trip• Redundant (hot/standby) operation with digital/analog

or digital/digital channel interfaces

The Distance Protection module in the GARD 8000 Systemcan provide back-up for the current differential protection,in case of channel failure. It can also operate in parallelwith the current differential providing an independent dif-ferent measuring principle. Or, it can be used as a stand-alone non-pilot or pilot distance protection.

Distance Relay

The GARD 8000 System is a complete Teleprotection and Re-lay Terminal for line protection and transfer trip applications.Communication interfaces for any medium are built-in, andup to 10 communication modules can be included in oneSystem for redundant or independent communications.

The “Base” configuration of the GARD 8000 System hasone teleprotection system built-in and additional telepro-tection modules can be added as required. Each digitalteleprotection system may transfer up to 32 functions, andan analog system up to 4. The GARD 8000 System can beequipped with a full Distance Protection Terminal and in-dependent Current Differential Relay.

Figure 20. Pass-through functionality

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Current DifferentialProtection

A current differential protection module can be integratedin the GARD 8000 System. Using one 64 kbps channel, thecurrent differential relay can use the same communicationlink as the teleprotection system module, or it can have itsseparate channel interface.

Duplicating the highly successful RFL 9300 measuring prin-ciple with its high speed operation, the GARD 8000 currentdifferential protection provides added flexibility and en-hanced functionality:

• Extended fault recording and oscillography with largerdynamic range and more digital signals

• Fault records directly in COMTRADE allows evaluationby use of any standard reader

• While still extremely simple to set, extended setting rangesare made available for increased system fault currentcoordination

• Transient block logic for added security at external faultclearing with ct errors

• Adjusts for different ct ratios by setting• High speed trip; ½ cycle minimum, 1 cycle typical• Is completely unaffected by channel delay errors up to

+/- 4 ms, as may be caused by asymmetric transmitand receive channels

• Optional GPS time synchronizing makes the protectionvirtually independent of channel delay errors

The protection modules in the GARD 8000 System are pro-vided with their own digital fault recorders (DFR’s). Theseare useful for evaluation of relay performance as they recordthe analog and digital quantities the relays used for theirdecision. However, the GARD 8000 System can also besupplied with an independent, separate Digital Fault Re-cording module. This module has its own input transform-ers for voltages and currents and may record the same, ordifferent analogs as the protection modules.

When the GARD 8000 System is supplied as a teleprotectionor Power Line Carrier device for use with existing, older relays,the DFR module is a cost efficient, simple way to achievefault recording capabilites for a protection terminal. Featuresinclude:

• 8 analog channels; 4 voltages and 4 currents• 64 digital channels from internal signals and/or inputs• 4000 Hz sampling rate• 10 Mb memory allows for 80 records of 500 ms duration each• Output directly in COMTRADE format for easy evalua-

tion by the use of any standard reader• Time tag by IRIG-B or the built-in GPS receiver

The Power Line Carrier (PLC) module in the GARD 8000System implements the functionality of the RFL 9785 ON/OFF PLC and the RFL 9780 FSK PLC, all in one device. FSKor ON/OFF operation is selectable and the DSP basedtransmitter and receiver allows full frequency programma-bility in the range 30 to 535 kHz.

The setting options include:• Selectable FSK or ON/OFF operation• Transmit frequency 30 to 535 kHz• Programmable receive bandwidth and frequency shift• Adjustable logic timers• Unblock, blocking, permissive, transfer trip or phase com-

parison applications

Power Line Carrier features include:• Channel monitoring• Built-in check back function; set for periodic check and/

or remotely activated• Extensive Sequence of Event Reporting• Local or remote interrogation• Built-in reflected power measurement

Power Line Carrier

Digital Fault Recorder

• Two- or three-terminal versions• Hot/stand-by redundant channel operation• Optional single pole trip logic

The distance protection has 4 measuring zones, eachsettable to forward or reverse.

The distance protection can operate as stepped distance withinstantaneous operation from Zone 1, Zone 2 and Zone 3time-delayed. It can alternatively be applied in a pilot scheme,selectable to permissive, unblocking or blocking. It may usethe same communications channel interface as the currentdifferential relay and/or teleprotection system, or a separatecommunications interface. Features include:

• 4 Zones, all reversible• Phase-phase and phase-ground mho• Selectable phase-ground quadrilateral characteristic• POTT, DCUB or DCB pilot schemes• High-set and inverse time overcurrent elements• Breaker failure protection• Redosing and sync check• Under- and overvoltage elements• Accurate Fault Locator• Digital fault records directly in COMTRADE format• Optional single pole trip logic• Dual-breaker version.

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10RFL Electronics Inc. (August 2004) GARD 8000

11RFL Electronics Inc. (August 2004) GARD 8000

gard 8000 system

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