Load Shedding Relay. Integrated Protection System OUTPUT 1 OUTPUT 2 OUTPUT 3 OUTPUT 4 OUTPUT 5 RELAY OK DIAGNOSTIC CO. INC.

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1 TM TM TM Load Sheddng Relay M-30 PROTECTION Integrated Protecton System COM TARGET/OUTPUT RESET 59 IPSlogc TM OUTPUT 59 8R IPSlogc TM OUTPUT OUTPUT 8R 8 # 8 # OUTPUT OUTPUT 3 OUTPUT 8 # OUTPUT 3 8 # OUTPUT 8 #3 OUTPUT 5 8 # RELAY OK 8 #3 OUTPUT 5 7 DIAGNOSTIC 8 # RELAY OK 7 DIAGNOSTIC COM TARGET/OUTPUT RESET M-30 LOAD SHEDDING RELAY M-30 LOAD SHEDDING RELAY BECKWIT H CO. INC. ELECT RIC Ma de n U.S.A. BECKW ITH CO. INC. EL EC TR IC Made n U.S.A. M-30 Standard Panel M-30 Vertcal Panel (Optonal) COM IPSlogc TM M-30 LOAD SHEDDING RELAY 59 8R 8 # 8 # OUTPUT OUTPUT OUTPUT 3 OUTPUT TARGET/OUTPUT RESET 8 #3 OUTPUT 5 BECKWITH CO. INC. ELECTRIC Made n U.S.A. 8 # 7 RELAY OK DIAGNOSTIC M-30 Horzontal Panel (Optonal) Voltage Collapse Mtgaton provdng -step undervoltage and -step underfrequency load sheddng functons Undervoltage blockng and negatve sequence overvoltage blockng for system faults provdes load sheddng securty Local and remote seral communcatons (MODBUS Protocol) for montorng and control functons 5 programmable outputs and programmable nputs

2 M-30 Load Sheddng Relay Protectve Functons -Step Phase undervoltage () protecton, sngle-phase and postve sequence -Step Phase undervoltage, selectable as sngle phase or postve sequence respondng, wth Negatve sequence overvoltage and three phase undervoltage supervson Phase overvoltage (59) protecton Four-step over/under frequency (8) protecton Rate of Change of Frequency (8R) protecton IPSlogc TM takes the contact INPUT status and functon status and generates OUTPUTS by employng (OR, AND, and NOT) boolean Logc and a tmer. Standard Features 5 programmable outputs, programmable nputs, and self-test output Oscllographc recordng (COMTRADE fle format) Tme-stamped sequence of events (SOE) recordng for 3 events Meterng of Voltage and Frequency One RS-3 port (COM) on front and one RS-3 or 85 port (COM) on rear M-38 IPScom For Wndows TM Communcatons Software MODBUS protocol Supports both 50 and 60 Hz applcatons Relay voltage nputs can be drectly connected (no VT requred) for voltages 80 V ac Contnuous Self-Dagnostcs Optonal Features M-380D IPSplot PLUS Oscllograph Analyss Software Horzontal and Vertcal panel mount versons avalable (see Fgures and )

3 M-30 Load Sheddng Relay PROTECTIVE FUNCTIONS Devce Number Functon Setpont Ranges Increment Accuracy Phase Undervoltage Pckup #, #, #3, # to 00%* 0.% 0.5 V or 0.5% Tme Delay #, #, #3, # to 860 Cycles Cycle Cycles** 7S Supervson Pckup to 00%* 0.% 0.5 V or 0.5% Tme Delay to 860 Cycles Cycle Cycles** S Pckup to 00%* 0.% 0.5 V or 0.5% Tme Delay to 860 Cycles Cycle Cycles** * Of nomnal voltage. ** When RMS (total waveform) s selected, tmng accuracy s O0 cycles or % element response s selectable as postve sequence voltage or phase-to-phase voltage. Negatve Sequence Overvoltage 7 Pckup #, # to 00%* 0.% 0.5 V or 0.5% Tme Delay #, # to 860 Cycles Cycle Cycles * Of nomnal voltage. Phase Overvoltage 59 Pckup #, # 00 to 50%* 0.% 0.5 V or 0.5% Tme Delay #, # to 860 Cycles Cycle Cycles** * Of nomnal voltage. ** When RMS (total waveform) s selected, tmng accuracy s O0 cycles or % 8 Over/Under Frequency Pckup #, #, #3, # to Hz 0.0 Hz 0.03 Hz (0.00 to Hz*) Tme Delay #,#, #3, # to 65,500 Cycles Cycle Cycles or 0.0% *Ths range apples to 50 Hz nomnal frequency models. The pckup accuracy apples to 60 Hz models at a range of 57 to 63 Hz, and to 50 Hz models at a range of 7 to 53 Hz. The accuracy s 0.5 Hz for a range of 5 to 57 Hz and 63 to 67 Hz (for 60 Hz nomnal) and to 7 Hz and 53 to 57 Hz (for 50 Hz nomnal). Rate of Change of Frequency 8R Pckup #, # 0.0 to 0.00 Hz/Sec. 0.0 Hz/Sec Hz/Sec. or 5% Tme Delay #, # 3 to 860 Cycles Cycle + 0 Cycles Negatve Sequence Voltage Inhbt 0 to 99% % 0.5% 3

4 M-30 Load Sheddng Relay PROTECTIVE FUNCTIONS (cont. cont.) Devce Setpont Number Functon Ranges IPSlogc TM Increment Accuracy IPS IPSlogc uses element trp commands, control/status nput state changes, communcaton ponts, output contact close sgnals to develop programmable logc schemes. Tme Delay # # to 860 Cycles Cycle Cycle or % Nomnal Settngs Nomnal Voltage 50 to 500 V* V VT Confguraton Lne-Lne/Lne-Ground/Lne-Ground-to-Lne-Lne** Seal-n Delay to 860 Cycles Cycle Cycle or % * Maxmum measured range for (59) functon settng s < 600 V. ** When lne-ground-to-lne-lne s selected, the relay nternally calculates the lne-lne voltage from the lneground voltages for all voltage-senstve functons. When lne-ground-to-lne-lne selecton s appled, the nomnal voltage selecton should be the lne-lne nomnal voltage (not lne-ground nomnal voltage).

5 M-30 Load Sheddng Relay Descrpton The M-30 Load Sheddng Relay provdes voltage load sheddng, frequency load sheddng or supervsed voltage or frequency load sheddng to assst n voltage collapse mtgaton. The M-30 Load Sheddng Relay can be ntegrated nto load sheddng schemes that are part of an Energy Management System (EMS), or nto automatc load sheddng schemes as defned by the IEEE Power System Relayng Commttee, Substaton Protecton Subcommttee, Workng Group K-. In load sheddng as part of EMS applcaton, a control sgnal s sent to multple remote swtches at partcpatng blocks of customers to nterrupt loads for predetermned ntervals. Ths method of load sheddng can be manually performed by dspatchers at the EMS control staton, or they may be automatc from the EMS usng the logc, measurement and ntellgence of the M-30. In the Automatc Load Sheddng scheme where voltage nstablty s caused by sudden loss of crtcal transmsson equpment or VAr generatng equpment (.e. very short collapse tme), the M-30 provdes the means to quckly arrest fast voltage drop by dsconnectng selected large blocks of customer load allowng voltage to recover. The securty of an undervoltage load settng scheme s ncreased wth multple phase detecton rather than sngle phase, proper tme coordnaton between fault clearng and the tme delay for load sheddng and also by usng varous supervson technques that prevent nusance trppng for voltage condtons that do not lead to collapse. Ths M-30 offers three-phase lne to lne or lne to ground confguraton, optmal pckup/seal-n tme delays from to 860 cycles, and negatve sequence voltage (7S) as well as undervoltage (S) supervsory functons that ensure securty and relable operaton. To ensure that all data s collected durng a load-sheddng event the M-30 has oscllographc recordng, storng 80 cycles of all measured parameters. Addtonally, the M-30 has a Sequence of Events (SOE) recorder bult-n to capture and store a total of 3 events wth msec resoluton tme stamp. Undervoltage Load Sheddng Area undervoltage can occur when there s a lack of reactve support for the load. Ths lack of reactve support manfests tself as an undervoltage condton, wth the undervoltage most severe at the load area requrng the reactve support. As load n the transmsson systems are approxmately symmetrcal on all three phases, the undervoltage condton s seen on all three phases. If the power system voltage profle over the system s vewed as a plane, the undervoltage event from lack of reactve support can be conceptualzed as a depresson from the.0 pu level nomnal) to some lower level, wth the lowest pont the area of hghest reactve support requrement. A method of ganng selectvty for load sheddng s to employ multple tme undervoltage elements. In that manner, the localzed areas wth the lowest voltage (hghest reactve power support requrements) are shed frst. When mplementng an undervoltage load sheddng scheme, t must be secure from asymmetrcal voltage depressons occurrng from unbalanced faults; sngle phase-to-ground, phase-to-phase, and phase-phase to phase-ground faults as well as three-phase faults and complete system de-energzatons. Asymmetrcal voltage depressons occurrng from sngle to phase-to-ground, phase-to-phase, and phase-phase to ground faults are detected by usng a negatve sequence overvoltage element (7S) as a supervson. Typcally set to 0.05 to 0. pu of nomnal voltage, f the adjustable threshold s exceeded, the undervoltage load sheddng s blocked. Three-phase faults that decrease the voltage symmetrcally across all three phases, as well as complete de-energzatons of the parts of the power system due to fault clearng or other sectonalzng, are detected by usng undervoltage supervson (S) on all phases. The undervoltage supervson s typcally set lower than the lowest survvable undervoltage that could occur from lack of reactve support before the entre system voltage collapses, typcally from 0.9 to 0.7 pu. If any phase voltage s lower than the adjustable settng, t s assumed that the condton s from a fault (any type, ncludng three-phase) or complete de-energzaton of that part of the system. 5

6 M-30 Load Sheddng Relay Meterng The relay provdes meterng of voltages and frequency. Meterng Accuraces are: Voltage: 0.5 V or 0.5%, whchever s greater (Range 0 to 600 V) Frequency: 0.03 Hz (from 57 to 63 Hz for 60 Hz models; from 7 to 53 Hz for 50 Hz models) Oscllographc Recorder The oscllographc recorder provdes comprehensve data recordng of all montored waveforms, nput contacts and output contacts, storng up to 0 cycles of data. The total record length s confgured for one or two parttons. A programmable post trgger delay (5 to 95%) s ncorporated to capture breaker operaton. The oscllograph s trggered ether remotely usng the seral nterface, or desgnated status nput sgnals or M-30 programmable output operatons. Storage of oscllographc records s nonvolatle, and wll be retaned even wthout power, as long as the on-board battery s healthy. Oscllographc data can be downloaded va seral communcaton n Common Format For Transent Data Exchange (COMTRADE) format as specfed by IEEE Standard C Sequence of Events A total of 3 nonvolatle events can be stored. The recorded nformaton ncludes the functon(s) operated, the functon(s) pcked up, nput/output contact status and tme stamp. The events can be retreved through the communcatons port. After the 3nd event s stored, addtonal events result n the oldest event beng dropped (FIFO). The nformaton s tme-stamped to ms resoluton. Calculatons The M-30 uses dscrete fourer transform (DFT) algorthm on sampled (3 tmes per cycle) voltage sgnals to extract fundamental frequency phasors for calculatons. The 59/ functon, when set for RMS measurement, uses a tme doman algorthm to calculate the voltage magntude. Power Input Optons Nomnal / V dc 8 V dc 0 V ac/5 V ac Range 9 to 36 V dc 36 to 75 V dc 85 to 50 V ac/v dc Burden <5 VA <5 VA <5 VA Sensng Inputs 3 Voltage Inputs: Rated nomnal voltage of 69 V ac to 80 V ac, 60 Hz (50 Hz user confgurable). Wll wthstand 600 V contnuous voltage. Source voltages may be lne-to-ground or lne-to-lne connected. Phase sequence ABC/ACB s selectable. Voltage transformer burden less than 0.5 VA at 0 V ac. Control/Status Inputs The control/status nputs, INPUT and INPUT, can be programmed to block any of the M-30 functons and trgger the oscllograph recorder. The control/status nputs accept only dry contacts and are nternally wetted (9 V dc) by the relay's power supply. A mnmum current of.3 ma s requred to avod spurous trggerng of the nput. 6

7 M-30 Load Sheddng Relay Output Contacts The fve programmable output relays, each wth a contact, are rated as per ANSI/IEEE C for trppng: make 30 A for 0. seconds. The hardware confguraton conssts of the followng: self-test alarm output contact (form 'c') wth a ratng of 8 A at 0 V ac, 5 A at 30 V dc, 5 V dc 0.5 A resstve, 0. A nductve. (form 'a') contacts whch carry 8A, break 6A at 0 V ac, break 0.A at 5 V dc, nductve break at 0.A. 3 (form 'c') contacts wth a ratng of 8A at 0 V ac, 5A at 30 V dc, 5 V dc 0.5A resstve, 0.A nductve. Any of the M-30 protectve functons can be ndvdually programmed to actvate the fve programmable outputs. The user can confgure the fve programmable outputs to ether energze or de-energze to ssue an output command. The outputs (excludng the self-test) can have two modes of operaton, LATCHING and NORMAL. The LATCHING mode requres an operator nterventon to deactvate the outputs after the condton for operaton has been removed. In the NORMAL mode, when the condton for trppng has been removed, the output(s) wll deactvate automatcally after the correspondng seal-n tmers have expred. IPSlogc TM Ths feature can be programmed utlzng the IPScom Communcatons Software. IPSlogc takes the contact nput status and functon status, and by employng (OR, AND, and NOT) boolean logc and a tmer, can actvate an output or change settng profles. Target/Status Indcators and Controls The RELAY OK LED reveals proper cyclng of the mcroprocessor. The DIAGNOSTIC LED provdes ndcaton of the error code (when flashng). The OSC TRIGGER LED ndcates that the oscllograph has been trggered. The remanng LEDs are used to ndcate whch protectve functon(s) have been trpped. OUTPUT and OUTPUT are used to ndcate the status of the output contacts. The output LEDs wll llumnate when the output contact relays are trpped. The TARGET/OUTPUT RESET button resets the target LEDs f the condtons causng the operaton have been removed. Holdng the TARGET/OUTPUT RESET button dsplays the present pckup status of the M-30 functons. The TARGET/OUTPUT RESET button wll deactvate the trpped output contact f the LATCHING mode was selected. (If the seal n tmer has already expred, the output contact wll deactvate mmedately.) Communcaton Communcatons ports nclude a front panel RS-3 port and a rear port user confgurable to RS-3 or RS-85. The RS-3 ports are connected physcally wth a DB-9 connector and the RS-85 port utlzes -wre nterface mountng screw termnals. M-38 IPScom For Wndows TM utlzng the MODBUS communcatons protocol n RTU mode, mplements seral, byte-orented asynchronous communcaton wth the M-30 and provdes the followng functons: Interrogaton and modfcaton of setponts Tme-stamped sequence of events nformaton for the 3 most recent events Real-tme meterng of all quanttes measured Downloadng of recorded oscllographc data Relay Setup 7

8 M-30 Load Sheddng Relay Tests and Standards Voltage Wthstand Delectrc Wthstand IEC ,500 V dc for mnute appled to each ndependent crcut to earth 3,500 V dc for mnute appled between each ndependent crcut NOTE:,500 V dc for power supply voltage optons (,, 8 V dc nputs). Impulse Voltage IEC Insulaton Resstance Power supply nput voltages, 0 V ac/5 V dc: 5,000 V pk, +/- polarty appled to each ndependent crcut to earth 5,000 V pk, +/- polarty appled between each ndependent crcut. by 50 μs, 500 ohms mpedance, three surges at every 5 seconds Power supply nput voltages,,, 8 V dc: 3,000 V pk, +/- polarty appled to each ndependent crcut to earth 3,000 V pk, +/- polarty appled between each ndependent crcut. by 50 μs, 500 ohms mpedance, three surges at every 5 seconds IEC > 00 Megaohms Electrcal Envronment Electrostatc Dscharge Test EN Class (8 kv) pont contact dscharge EN Class (5kV) ar dscharge Fast Transent Dsturbance Test EN Class A ( kv,.5 khz) ANSI/IEEE,500 V pk oscllatory appled to each ndependent crcut to earth C ,500 V pk oscllatory appled between each ndependent crcut 00,000 V pk Fast Transent burst appled to each ndependent crcut to earth,000 V pk Fast Transent burst appled between each ndependent crcut 5,000 V pk Fast Transent appled to each ndependent crcut to earth 5,000 V pk Fast Transent appled between each ndependent crcut NOTE: The sgnal s appled to the dgtal data crcuts (RS-3, RS-85) through capactve couplng clamp. ANSI/IEEE C V/m Output Contacts ANSI/IEEE Make 30 A for 0. seconds, off for 5 seconds for,000 operatons, per Secton 6.7., C Trppng Output Performance Requrements 8

9 M-30 Load Sheddng Relay Atmospherc Envronment Temperature IEC Cold, 0 C IEC Dry Heat, +70 C IEC Damp Heat, +0 93% RH Mechancal Envronment Vbraton IEC Vbraton response Class, 0.5 g Vbraton endurance Class,.0 g Shock MIL-STD-80C Method 56., Procedure, ms, 5 g, / sne pulse, 3 pulses per axs Complance culus-lsted per 508 Industral Control Equpment Industral Control Equpment Certfed for Canada CAN/CSA C. No. -M9 culus-lsted Component per 508A Table SA. Industral Control Panels Physcal Panel Mount Sze:.0" hgh x.00" wde x.56" deep (30.99 cm x 30.8 cm x 7. cm) Approxmate Weght: 5 lbs, oz (. kg) Approxmate Shppng Weght: 9 lbs, 3 oz (.8 kg) Horzontal/Vertcal Panel Mount Sze: 3.6" hgh x 0.50" wde x.63" deep (8.8 cm x 6.7 cm x 9.5 cm) Approxmate Weght: 6 lbs, oz (.8 kg) Approxmate Shppng Weght: 0 lbs, oz (0.7 kg) Recommended Storage Parameters Temperature: 5 C to 0 C Humdty: Maxmum relatve humdty 80% for temperatures up to 3 C, decreasng to 3 C lnearly to 50% relatve humdty at 0 C. Envronment: Storage area to be free of dust, corrosve gases, flammable materals, dew, percolatng water, ran and solar radaton. See M-30 Instructon Book, Appendx D, Layup and Storage for addtonal nformaton. Patent & Warranty The M-30 Load Sheddng Relay s covered by U.S. Patent 5,59,393. The M-30 Load Sheddng Relay s covered by a fve year warranty from date of shpment. External Connectons M-30 external connecton ponts are llustrated n Fgure, Standard Panel Layout External Connectons and Fgure for the optonal Horzontal and Vertcal Panel External Connecton Layouts. Specfcaton s subject to change wthout notce. 9

10 M-30 Load Sheddng Relay TOP WARNING! RS3 CONTACT WITH TERMINALS MAY CAUSE ELECTRICAL SHOCK RX+ RX- TX+ TX- GND RS-85 COM 3 F 3.5A, 50V F 3.5A, 50V F F POWER SUPPLY 3 OUT OUT CAUTION DRY CONTACT INPUTS ONLY /60 HZ 5 VA IN RETURN IN 5 5 IN 6 7 OUT3 OUT 3 8 NOT USED 9 0 VA OR VAB OUT5 0 9 VB OR VBC 69-80VAC 50/60 HZ NOMINAL V C OR V CA SELF - TEST 6 5 BECKWITH ELECTRIC CO. INC th AVE NO. LARGO, FL Patent No. 5,59,393 Fgure Standard Panel Layout External Connectons (Elevaton Vew) NOTES:!. See M-30 Instructon Book, Secton.3, External Connectons.. See M-30 Instructon Book, Secton 3., Relay Confguraton, Output Contact Mode. 3. See M-30 Instructon Book, Secton.8, Relay Remote Communcaton Setup (PC), COM Confguraton.. See M-30 Instructon Book, Secton.3, External Connectons. 0

11 M-30 Load Sheddng Relay FRONT PANEL PANEL 5 6 SELF - TEST VC OR VCA VAC 50/60 HZ NOMINAL VB OR VBC 9 0 OUT5 VA OR VAB 0 9 NOT USED 8 OUT 7 3 OUT IN IN IN RETURN CAUTION DRY CONTACT INPUTS ONLY OUT /60 HZ 5 VA POWER SUPPLY OUT F F F 3.5A, 50V F 3.5A, 50V WARNING! CONTACT WITH TERMINALS MAY CAUSE ELECTRICAL SHOCK COM 3 RS-85 RS3 GND TX- TX+ RX- RX+ BECKWITH ELECTRIC CO. INC th AVE NO. LARGO, FLORIDA U.S.A Patent No. 5,59,393 REAR Fgure Optonal Horzontal and Vertcal Panel External Connecton Layout (Plan Vew) NOTES:!. See M-30 Instructon Book, Secton.3, External Connectons.. See M-30 Instructon Book, Secton 3., Relay Confguraton, Output Contact Mode. 3. See M-30 Instructon Book, Secton.8, Relay Remote Communcaton Setup (PC), COM Confguraton.. See M-30 Instructon Book, Secton.3, External Connectons.

12 M-30 Load Sheddng Relay.000 [30.80] [5.] [03.0].688 [.88] 0.3 [7.9].500 [63.50] COM.788 [5.] 59 8R 8 # 8 # IPSlogc TM OUTPUT OUTPUT OUTPUT 3 OUTPUT.00 [309.88].000 [9.] CUTOUT 8 #3 8 # 7 OUTPUT 5 RELAY OK DIAGNOSTIC [03.] 0.70 [.3] M-30 LOAD SHEDDING PROTECTION R TARGET/OUTPUT RESET BECKWITH ELECTRIC CO. INC. Made n U.S.A..788 [5.] [3.05] CUTOUT 0.65 [5.87] 0.80 Dameter Through [7.] Fgure 3 Standard Panel Mountng Dmensons

13 R M-30 Load Sheddng Relay.50 [37.50] 0.38 [9.53].75 [98.5] 0.8 [.9] COM IPSlogc TM 3.6 [87.88].50 [63.50] M-30 LOAD SHEDDING RELAY 59 8R 8 # 8 # 8 #3 OUTPUT OUTPUT OUTPUT 3 OUTPUT OUTPUT 5 TARGET/OUTPUT RESET 8 # RELAY OK BECKWITH ELECTRIC CO. INC. 7 DIAGNOSTIC Made n U.S.A [7.] Dameter Through 0.95 [8.8] CUTOUT OPTIONAL MOUNTING IN IN IN RETURN + SELF-TEST OUT5 OUT /60 HZ 5 VA CAUTION DRY CONTACT INPUTS ONLY POWER SUPPLY 69-80VAC 50/60 HZ NOMINAL VC,OR VCA VB OR VBC VA OR VAB NOT USED OUT3 OUT OUT [53.95].63 [95.35] F F F 3.5A, 50V F 3.5A, 50V WARNING! CONTACT WITH TERMINALS MAY CAUSE ELECTRICAL SHOCK 3 COM RS-85 RS3 RX- RX+ GND TX- TX+ RX- RX+ COM RS3 RS-85 GND TX- TX+ BECKWITH ELECTRIC CO. INC th AVE NO. LARGO, FLORIDA U.S.A Patent No. 5,59, [66.70] Fgure Optonal Horzontal/Vertcal Panel Mountng Dmensons NOTES:!. See M-30 Instructon Book, Secton.3, External Connectons. See M-30 Instructon Book, Secton 3., Relay Confguraton, Output Contacts Mode. 3. See M-30 Instructon Book, Secton.8, Relay Remote Communcaton Setup (PC), COM Confguraton. See M-30 Instructon Book, Secton.3, External Connectons. 3

14 M-30 Load Sheddng Relay Undervoltage Load Shed Element Postve Sequence Undervoltage Note V < Setpont Supervsons Undervoltage Block Negatve Sequence Overvoltage Block S Note 7S Note 3 V A < Setpont V B < Setpont V C < Setpont V > Setpont OR AND Pck Up Tmer Undervoltage Trp Fgure 5 Postve Sequence Undervoltage Element NOTES:. The undervoltage load shed element s selectable as ether postve sequence undervoltage or three phase undervoltage.. The S supervses and blocks undervoltage load sheddng when the system s de-energzed or durng three-phase faults. 3. The 7S supervses and blocks undervoltage load sheddng durng sngle and two-phase faults. Undervoltage Load Shed Element Three Phase Undervoltage Note V A < Setpont # V B < Setpont # V C < Setpont # AND Supervsons Undervoltage Block Negatve Sequence Overvoltage Block S Note 7S Note 3 V A < Setpont # V B < Setpont # V C < Setpont # V > Setpont OR AND Pck Up Tmer Undervoltage Trp Fgure 6 Three Phase Undervoltage Element NOTES:. The undervoltage load shed element s selectable as ether postve sequence undervoltage or three phase undervoltage.. The S supervses and blocks undervoltage load sheddng when the system s de-energzed or durng three-phase faults. 3. The 7S supervses and blocks undervoltage load sheddng durng sngle and two-phase faults.

15 M-30 Load Sheddng Relay Transmsson System 5 M-30 Load Sheddng Relay Programmable I/O LED Targets 8R * or 5 Meterng 7S S Sequence of Events Loggng Waveform Capture (COMTRADE) Dstrbuton Substaton User Interface wth PC Communcatons * VTs may be necessary dependng on applcaton voltage. Fgure 7 Typcal One-Lne Dagram Load Sheddng - Dstrbuton M-30 Load Sheddng Relay or * Programmable I/O LED Targets 8R Meterng 7S S System A System B Sequence of Events Loggng Waveform Capture (COMTRADE) User Interface wth PC VTs may be necessary dependng * on applcaton voltage. Communcatons Fgure 8 Typcal One-Lne Dagram Load Sheddng - Transmsson/Sub-transmsson 5

16 M-30 Typcal Connecton Dagram Alternate VT connecton, phase voltages VTs are not necessary f the Nomnal Rated Interconnecton Voltage s < 80 V ac. Three VT Wye-Wye Connecton Two VT Open-Delta Connecton M-30 M A B C A B C A B C M-30 M-30 Fgure 9 Typcal Three-Lne Dagram Load Sheddng Applcaton Regstered ISO 900:000 BECKWITH ELECTRIC CO., INC th Avenue North Largo, Florda U.S.A. PHONE (7) 5-36 FAX (7) marketng@beckwthelectrc.com WEB PAGE 00 Beckwth Electrc Co. Prnted n U.S.A. (.6.0) SP-0 0/07