Eaton CUTLER-HAMMER MD-3000 series Installation, Operation And Maintanance

MD-3000 Instruction LeafletIB02602001E Effective: Date 03/06For more information visit: www.EatonElectrical.comInitial Release1-1.1 WARRANTY AND LIABILITY INFORMATIONNO WARRANTIES, EXPRESSED OR IMPLIED,INCLUDING WARRANTIES OF FITNESS FOR APARTICULAR PURPOSE OF MERCHANTABILITY, ORWARRANTIES ARISING FROM COURSE OF DEALINGOR USAGE OF TRADE, ARE MADE REGARDING THEINFORMATION, RECOMMENDATIONS ANDDESCRIPTIONS CONTAINED HEREIN.In no event will Eaton Cutler-Hammer be responsible tothe purchaser or user in contract, in tort (includingnegligence), strict liability or otherwise for any special,indirect, incidental or consequential damage or losswhatsoever. Including but not limited to damage or loss ofuse of equipment, plant or power system, cost of capital,loss of power, additional expenses in the use of existingpower facilities or claims against the purchaser or user byits customers resulting from the use of the information anddescriptions contained herein.1-1.2 SAFETY PRECAUTIONSAll safety codes safety standards and/or regulations mustbe strictly observed in the installation, operation andmaintenance of this device.THE WARNINGS AND CAUTIONS INCLUDED ASPART OF THE PROCEDURAL STEPS IN THISDOCUMENT ARE FOR PERSONNEL SAFETY ANDPROTECTION OF EQUIPMENT FROM DAMAGE.THIS IS AN EXAMPLE OF A TYPICAL WARNINGLABEL. THIS WILL HELP TO ENSURE THATPERSONNEL ARE ALERTED TO CAUTIONS THATAPPEAR THROUGHOUT THE DOCUMENT.COMPLETELY READ AND UNDERSTAND THEMATERIAL PRESENTED IN THIS DOCUMENTBEFORE ATTEMPTING INSTALLATION,OPERATION OR APPLICATION OF THEEQUIPMENT. ONLY QUALIFIED PERSONSSHOULD BE PERMITTED TO PERFORM ANYWORK ASSOCIATED WITH THE EQUIPMENT. ANYWIRING INSTRUCTIONS PRESENTED IN THISDOCUMENT MUST BE FOLLOWED PRECISELY.FAILURE TO DO SO COULD CAUSE PERMANENTEQUIPMENT DAMAGE, BODILY INJURY ORDEATH.1-2 GENERAL INFORMATIONThe MD-3000 Protective Relay is a panel-mountedmicroprocessor based self-balancing differential currentrelay, designed for both ANSI and IEC applications(Figures 1-1 and 1-2). It is a self-contained device thatoperates from either ac or dc control power and providestrue rms sensing of each phase differential current. Onlyone relay is required per three-phase circuit. An integralpart of each device is the differential current monitoringand the ability to select protective functions.THE LOSS OF CONTROL VOLTAGE WILL CAUSETHE MD-3000 TO BE INOPERABLE. IF ACCONTROL VOLTAGE IS USED AN APPROPRIATERELIABLE POWER SOURCE/SCHEME SHOULDBE SELECTED (POSSIBLY AN UPS SYSTEM) TOSUPPLY POWER TO THE RELAY.The MD-3000 Motor/Generator Protective Relay providesdifferential current protection for motors and generators.MD-3000 Protective Relays are compatible for use with allcircuit breakers utilizing a shunt trip coil.The MD-3000 is intended to replace electromechanicaldifferential protection relays.1-3 FUNCTIONS/FEATURES/OPTIONSThe primary function of the MD-3000 Protective Relay isdifferential overcurrent protection. This is achieved byanalyzing the secondary current signals received from theswitchgear current transformers. This secondary currentrepresents the current differential between the input andoutput of a motor or generator. When the userprogrammed current levels are exceeded for a period oftime greater than the user programmed time delay setting,the closing of trip contact(s) is used to initiate breakertripping.The MD-3000 Protective Relay operates from thesecondary output of standard switchgear currenttransformers rated at 5 amperes. It is configured to fitspecific distribution system requirements. The phase CTratios can be independently programmed over a range of5:5 to 5000:5. Refer to Table 2.1 for the available CT ratiosettings.The relay automatically exits the program mode if there isno programming activity for 2-1/2 minutes. Programmingand test mode security are provided by a sealed, hingedaccess cover on the front of the relay. Displays indicatethe value currently being considered, while multi-coloredLED’s indicate operational conditions and specificfunctions.In addition to performing a continuous self-testing ofinternal circuitry, all MD-3000 Protective Relays includefield testing capabilities that are accessible from the frontpanel. To check that all tripping features are functioningproperly a test current simulates a differential overcurrentcondition. Refer to Paragraph 2-1.5 for additionalinformation.MD-3000 Motor/Generator Differential Relay operatingparameters and troubleshooting information are displayedWARNING