Motor & generator protection example settings

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Motor & generator protective relays example settings

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Motor & generator protection example settings

  1. 1. Motor protection exampleAssume you have a motor rated 500 HP, .95 power factor & 90 % efficiency energized from a 4.16 Kvsource, using a microprocessor motor protection relay, provide the typical settings.The full load current can be taken from the motor nameplate as well as the service factor. The motorfull load current can be calculated from the following: I = 500 (.746)/1.732 (4.16)(.85)(.9) =60 amps Motor and Line Data FunctionsFunction Description Adjustment / Display Range Setting Increments SettingMotor Nameplate FLA 1 – 2000A, adjustable between 50-100% of Max Amp Rating.FLA must be programmed Upper limit of range automatically adjusts 1 60for relay to function downward as Service factor is increased.Motor Nameplate 1.00 - 1.30 SF .05 1Overload Class During Start NEMA / UL Class 5 – 20 5 Class 20Overload Class During Run NEMA / UL Class 5 – 30 5 Class 10Overload Reset 0 = Manual,1 = Auto,2 = Disabled Overload 1 1kV Voltage Input (nominal line, Medium Voltage) .60 – 15kV .01 4.16Line Frequency 50 or 60 Hz 60Acceleration Time 0-300 seconds [0=Disabled] 1 30Current Imbalance Trip % 0.1 - 30% of FLA [0=Disabled] 1(%) 15Current Imbalance Trip Delay 1 - 20 seconds 1 (Second) 5Over Current Trip % 0,.50 – 300% of FLA [0=Disabled] 1 (%) 200Over Current Trip Delay 1 - 20 seconds 1 8Under Current % 0, 10 – 90% of FLA [0=Disabled] 1 (%) 35Under Current Trip Delay 1 - 60 seconds 1 15Stall Detection Trip Level 0.100 – 600% of FLA [0=Disabled] 5 (%) 600Stall Detection Trip Delay 1 - 10 seconds 1 4Peak Current Trip % 0.800 – 1400% [0=Disabled] 10(%) 1000 (%)Peak Current Trip Delay 0..01 - .5 seconds .01 .0513/11/10 1
  2. 2. Ground Fault Current Trip Value 0.5 – 90% of CT Value [0=Disabled] 1 (%) 50Ground Fault Current Trip Delay 1 – 60 seconds 1 5 Voltage Protection SettingsVoltage Imbalance Trip % 0.1 – 30% [0=Disabled] 1 (%) 20Voltage Imbalance Trip Delay 1 – 20 seconds 1 10Over Voltage Trip % 0.1 – 10% [0=Disabled] 1 (%) 5Over Voltage Trip Delay 1 – 20 seconds 1 10Under Voltage Trip on Start % 0.1 – 20% [0=Disabled] 1 (%) 20UV Trip on Start Delay 1 – 180 seconds 1 20Under Voltage Trip on Run % 0.1 – 20% [0=Disabled] 1 (%) 20UV Trip Delay during Run 1 – 20 seconds 1 10 Phase and Frequency Protection SettingsPhase Rotation Trip 0.1 or 2 0=Disabled, 1=ABC, 2=ACB] 1 2Phase Rotation Trip Delay 1 – 20 seconds 1 2Phase Loss Trip and Delay 0.1-20 Seconds [0= Disabled] 1 5Over Frequency Trip Limit 0.1 – 10Hz [0=Disabled] 1 1Over Frequency Trip Delay 1 – 20 seconds 1 5Under Frequency Trip Limit 0.1 – 10Hz [0=Disabled] 1 1Under Frequency Trip Delay 1 – 20 seconds 1 5Motor KW Trip 0-2.0 = Disabled,1 = Over KW Trip,2 = Under KW Trip 1 0Motor KW Trip Point 20 – 100% of full load KW (disabled) 1% 20(%)Motor KW Trip Delay Time 1 – 999 minutes (disabled) 1 1Power Factor Trip Range 0.1 – 3 [0=Disabled, 1=lag, 2=lead, 3= lead/lag] 1 2Power Factor Trip Point .01 – 1 .01 .10Power Factor Trip Delay Time 1 – 20 seconds 1 1013/11/10 2
  3. 3. Power Factor Current Direction 0 - 1, [0=Normal, 1= Reversed] 1 1 Lockout / Inhibit SettingsCoast Down (Back Spin) Lockout Timer 0 = Disabled, or 1 - 60 minutes 1 minute 1Maximum Starts per Hour 0 = Disabled, or 1 – 10 starts 1 5Minimum Time Between Starts Inhibit 0 = Disabled, or 1 - 60 minutes 1 minute 12Note: NEMA Class trip curves are based on a common tripping point of 600% of motor Full LoadAmps (FLA). Curves vary by the amount of time before the unit trips. As an example, a Class 20 curvewill trip in 20 seconds at 600% of FLA. Another example, Class 10 will trip in 10 seconds at 600% ofFLA.PT Value:1-200 (: 1) 1:1 = direct voltage input, 2-200: 1 = kV Voltage Input 1 40 (4160/104) VCT Value: 5-2000 (:5) 5 60Number of Turns through CT: 1 – 5 (in 1 increments) 1 Generator protection exampleRatings of generators:Rated output (eg. 1,120 MVA), Maximum output (1230 MVA), Rated rotation speed (300 rpm), Powerfactor (0.9), Number of poles (2), Terminal voltage (27), Rated Armature current (23949), MaximumArmature current (26302), Short-circuit ratio (> or = 0.5), Hydrogen gas pressure (0.52 Mpa G),Insulation type (F), Temperature rise class (B), Cooling method (Stator: direct water), Efficiency(99 %), Hydrogen consumption (12 m3/day).Functional Specifications of generator protective relayNOMINAL SYSTEM FREQUENCY SETTING RANGE.............................................50 or 60 HzRATED PRIMARY INPUT CURRENT OF PHASE AND NEUTRAL CTS .........1 - 9999A in 1A stepsRATED PRIMARY SYSTEM PHASE-TO-PHASE VOLTAGE OF PTS......2 – 655 kV in .0.1 kV stepsRATED PT SECONDARY LINE-TO-LINE VOLTAGE ...............................50 – 125 V in 1 V stepsLOW SET OVERCURRENT ELEMENTCharacteristic: .......................................................................................Definite time or inversePickup: ...........................................................................................1.0 – 2.5 pu of rated generator currentTime delay: ...........................................................................................0.05 – 30.0 seconds (at 5pu Igen)HIGH SET OVERCURRENT ELEMENTCharacteristic: .......................................................................................Definite timePickup: ............................................................................................1.0 – 9.9pu of rated generator currentTime delay: ...........................................................................................0.05 – 3.0 seconds (at 5pu Igen)CURRENT UNBALANCE ELEMENTMaximum negative sequence current rating;.................................0.05 – 0.5pu of rated generator current13/11/10 3
  4. 4. Time multiplier of I2 t curve ...................................................................5 – 80 secondsCooling time to rated.............................................................................10 – 1800 secondsAlarm level pickup.................................................................................0.03 – 0.5pu generator currentAlarm level time delay...........................................................................1 – 100 secondsREVERSE POWER ELEMENT PICKUP ......................................0.02 to 0.2pu rated generator currentTime delay ...........................................................................................1 – 100 secondsLOSS OF FIELD ELEMENTMho circle size ..........................................................................50 – 300% of rated generator impedanceMho offset .................................................................................5 – 50% of rated generator impedanceTime delay ............................................................................................0.2 – 60 secondsIntegration time .....................................................................................0 – 10 secondsVOLTAGE ELEMENTSCharacteristic ........................................................................................Over, Under or Over+UnderPick-up level.......................................................................................1 – 50% change from rated voltageTime delay ............................................................................................0.1 – 60.0 secondsFREQUENCY ELEMENTSCharacteristic ........................................................................................Over, Under or Over+UnderPick-up level..........................................................................................0.05 – 9.99Hz from nominalTime delay ............................................................................................0.1 – 60.0 secondsTHERMAL IMAGE ELEMENTTrip level ...............................................................................................Fixed at 110% ratedThermal time constant of alternator ......................................................1 – 400 minutesPre-alarm level......................................................................................50 – 110% of ratedUNDERPOWER ELEMENT PICKUP LEVEL ..........................................................0.05 – 1.00 ofrated power outputTime delay ............................................................................................0.1 – 60.0 secondsUNDERIMPEDANCE ELEMENTSPickup level...........................................................................................01 – 1.0 pu rated impedanceTime delay ............................................................................................0.02 – 9.99 secondsFIRST LEVEL OVEREXCITATION ELEMENTCharacteristic ........................................................................................InversePickup level...........................................................................................1.0 - 2.0 puTime multiplier.......................................................................................0.5 – 5.0SECOND LEVEL OVEREXCITATION ELEMENTCharacteristic ........................................................................................Definite timePickup level...........................................................................................1.0 - 2.0 puTime multiplier.......................................................................................0.1 – 60.0 seconds95% STATOR GROUND FAULT ELEMENTSPickup level.....................................................................................5 – 99% Rated zero sequence voltageTime delay ............................................................................................0.05 – 99.0 seconds100% STATOR GROUND FAULT ELEMENT3rd Harmonic Pickup level ..............................................................1 – 30% Rated zero sequence voltageTime delay ............................................................................................0.05 – 99.0 seconds Typical Settings IEEE No. Function Typical Settings and Remarks24 Overexcitation PU: 1.1*VNOM/60; TD: 0.3; reset TD: 5 alarm P.U.: 1.18*VNOM/6013/11/10 4
  5. 5. alarm delay: 2.5s25 Synchronism Check Max Slip: 6RPM; Max phase angle error: 10° Max VMAG error: 2.5% VNOM32 Reverse Power (one stage) PU: turbine 1% of rated; 15 s . PU: Reciprocating engine: 10% of rated; 5 s32-1 Reverse Power (non-electrical, trip supervision) PU: same as 32; 3 s40 Loss-of-field (VAR Flow approach) Level 1 PU: 60% VA rating; Delay: 0.2s; Level 2 PU: 100% VA rating: 0.1s46 Negative Sequence overcurrent I2 PU: 10% Irated; K=1049 Stator Temperature (RTD) Lower: 95°C; upper: 105°C50/87 Differential via flux summation Cts PU:10% INOM or less if 1A relay may be used50/27 IE Inadvertent Energization Overcurrent with 27, 81 50: 0.5A (10% INOM) 27: 85% Supervision VNOM (81: Similar)51N Stator Ground Over- current (Low, Med Z Gnd, PU: 10% INOM; curve: EI; TD: 4. Inst: Phase CT Residual) none. Higher PU required to coordinate with load. No higher than 25% INOM.50/51N Stator Ground Over- current (Low, Med Z Gnd, P.U.: 10% INOM; Curve EI**, TD4; Inst Neutral CT or Flux Summation CT) 100% INOM. Higher PU if required to coordinate with load. No higher than 25% INOM.51GN, 51N Stator Ground Over- current (High Z Gnd) PU: 10% IFAULT at HV Term.; Curve: VI***; TD:4.51VC Voltage Controlled overcurrent PU: 50% INOM; Curve: VI***; TD: 4. Control voltage: 80%VNOM.51VR Voltage Restrained overcurrent PU: 175% INOM; Curve: VI***; TD: 4. Zero Restraint Voltage: 100% VNOM L-L59N, 27-3N, 59P Ground Overvoltage 59N: 5% VNEU during HV terminal fault; 27-3N: 25% V3rd during normal operation; TD: 10s 59P: 80% VNOM67IE Directional O/C for Inadvertent Energization PU: 75-100% INOM GEN; Definite Time (0.1- 0.25 sec.) ; Inst: 200% INOM GEN13/11/10 5
  6. 6. 81 Over/under frequency For Generator protection: 57, 62Hz, 0.5s; For Island detection condition: 59, 61Hz, 0.1s87G Generator Phase Differential Fixed: 0.4A; or Variable: Min P.U.: 0.1 * Tap; Tap: INOM; Slope: 15%87N Generator Ground Variable: Min P.U.: 0.1 times tap; Slope 15%; Differential Time delay: 0.1s; choose low tap 67N: current polarization; time: 0.25A; Curve: VI***; TD: 2; Instantaneous: disconnect87UD 13 Unit Differential Min PU: 0.35*Tap; Tap: INOM; Slope 30%**: EI: extremely inverse.***: VI: very inverse.13/11/10 6

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