GE Digital Energy Motor Protection Application in 869 Motor Protection Application in 869
GEDigital Energy
Motor Protection Application in 869Motor Protection Application in 869
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869 Advanced Motor Protection
869
Proven Thermal
ModelDifferential
Start Supervision
InductionSynchronous
Motors
Cyclic LoadsHigh Inertia
Loads
VFD / VSDDual Speed
ESAMCSA
Monitoring & Diagnostics
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869 - Proven Thermal Model
Thermal model differentiators
869 Advantages
Accuracy • 0.25% CT accuracy delivers precise thermal replica of motor condition
Simplicity • Simple motor load current based algorithm.• Not dependent on motor equivalent circuit model.
Dependability • Dependable due to consideration for all motor operating conditions• Starting, stalling, running or stopping etc. • Interlocking with thermal lockout.
Reliability • More accurate modeling of thermal capacity for Hot stator at near full load prolonged running by considering the cooling effect.
• RTD bias thermal model to cover for change in temperatures. • Unbalance biasing to consider additional rotor heating.
Easy to setup • Thermal model can be setup with as low as 8 settings. • Even advanced applications setup is simple.
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869 - Proven Thermal Model
Thermal model differentiators
869 Advantages
Flexibility • Standard curve +• Flex curves to customize for special applications • IEC curve • Separate cooling time constants for running and stopped• Programmable Hot/Cold ratio
Special applications VFD, Cyclic loading, High inertia loads – VD : comprehensive coverage
RTD BiasingFlexCurve VD Overload CurvesUnbalance Biasing
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869 - Cyclic Load Application
1-Cycle RMS FilterInput Motor Currents Filtered Motor Load Motor Load curve
1-Cycle RMS FilterInput Motor Currents Unfiltered Motor Load Motor Load curve
Multilin 869 thermal Overload Protection
Conventional thermal Overload Protection
Thermal model response - Match heating time to cooling time constant
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869 - Cyclic Load Application
Motor Load Filter Interval• N = P/2• N – number of cycles to average• P – number of poles• Elements that use filtered current
• Acceleration Time• Current Unbalance• Mechanical Jam• Overload• Thermal Model• Undercurrent• Power Factor• Power
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869 - VFD Application
Source Side VFD Protection Load Side Motor Protection
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869 - VFD Application
Motor Load Filter Interval• Frequency tracking switched from voltages to
currents• Frequency range of 3Hz to 72Hz.• Thermal Model Voltage Dependent (VD) function is
blocked• VFD Not Bypassed operand could be used to block
the voltage elements.• All motor current functions except Short Circuit,
Ground Fault and Differential elements are using “Motor Load Filter Interval”
• When VFD configuration support “Function” is enabled and Bypass Switch is closed, then frequency tracking source will be switched back from currents to voltages, all voltages elements will work as normal
• All motor functions will then be using the normal RMS currents
869 – Stator Differential Application869 – Stator Differential Application
Differential• True differential or Core
balance differential • Proven CT saturation – DC,
AC and DIR algorithms• Restrain factor in Core
balance approach for starting period
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869 Application for Brushless Synchronous Motor
SpeedRotor MonitorStator, Air & Brg RTD’sCooling Fan MotorsAnti-condensation HeatersVibration & Key phasor sensorsAir Filter Differential Pressure Switches
Motor Exc
ProcessControl
BrushlessExcitation
Control
Differential CT’s
Phase CT’s
SurgeCapacitors
LightningArrestors
Ground CT
Line PT’sExcitation
Power Transforme
r
Motor StarterCircuit BreakerOr Contactor
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869 Application for Brushless Synchronous Motor
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Embedded Arc Flash Protection
• Platform feature….Motor, Feeder typically
• Light and overcurrent based detection
• Supports up to 4 input sensors
• Arc flash detection for major equipment compartments and bus in less than 2 msec
• Active self-diagnostics
Breaker/Contactor ControlBreaker/Contactor Control
Breaker or Contactor ControlBreaker or Contactor Control
Breaker or Contactor ControlBreaker or Contactor Control
Advantages• Control algorithm for either
breaker or contractor
• Simple inputs to select correct operating mode
• Auxiliary Relay settings enable auxiliary relay operation for Breaker Close
Breaker or Contactor Settings AutopopulateBreaker or Contactor Settings Autopopulate
Flexibility of Contact OutputsFlexibility of Contact Outputs
Trip and Close RelaysTrip and Close Relays
Can be configured for Failsafe or Non-Failsafe
869 – Motor Monitoring & Diagnostics Applications869 – Motor Monitoring & Diagnostics Applications
Motor Reports in the 869Motor Reports in the 869
869 Environmental Monitoring869 Environmental Monitoring
Histogram of operating conditions :• Temperature• Humidity• Transient voltage (Surge)• Mechanical shock (Vibration)
Historical data for Environmental Analysis
869 Motor Start Data Logger869 Motor Start Data Logger
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869 Data LoggerData Logger• 16 analog values • Recorded at the rate of:
• 1 cycle• 1 second, 30 seconds, 1 minute • 15 minutes, 30 minutes, 1 hour
• Ability to capture Minimum, Maximum and Mean over a period of time
Data Logger applications• Coordinated data capture for enhanced analysis of
protection coordination• Thermal model operational analysis using snap
shots of motor parameters• Long term temperature trending
869 Motor Learned Data869 Motor Learned Data
Advanced Motor Health ReportAdvanced Motor Health Report
High Speed IEC61850 / PRP Application
Device Overview
General information on the motor
Status Overview
Summarizes historical data and status of the motor
Trip Summary Summary of events that resulted in the motor trip
Motor History Events associated with operating conditions
Motor Starting
Collects and displays the learned data from starting
Motor Start Displays the start data, including presents the 60-second long detailed start data
Motor Stop/Trip
Provides events that are specifically related to the stopping and tripping of the motor
Broken Rotor Bar Detection Broken Rotor Bar Detection
Broken Rotor Bar OverviewBroken Rotor Bar Overview
Broken Bar Overview• A serious problem that is caused
by severe duty cycles
• Often no initial performance issues, but serious secondary effects
• Loss of production and costly repairs often required
Broken Rotor Bar Detection OverviewBroken Rotor Bar Detection Overview
Detection Overview• Under healthy rotor conditions,
only the slip frequency (s*fs) current is present in the rotor
• Rotor bar defect (negative slip frequency component) causes modulation of the stator current fs*(1-2*s)
• Electromagnetic torque and speed oscillation occur at twice the slip frequency
• Strongest fault signature at frequency fs(1±2s)
Detection Overview• Under healthy rotor conditions,
only the slip frequency (s*fs) current is present in the rotor
• Rotor bar defect (negative slip frequency component) causes modulation of the stator current fs*(1-2*s)
• Electromagnetic torque and speed oscillation occur at twice the slip frequency
• Strongest fault signature at frequency fs(1±2s)
Theoretical representation of rotor bar fault signature
Conventional Broken Rotor Bar Detection Conventional Broken Rotor Bar Detection
Conventional Broken Rotor Bar DetectionConventional Broken Rotor Bar Detection
Fast Fourier Transformation (FFT) used to analyze frequency domain of motor current
Motor Current Signature Analysis (MCSA)
• Broken Rotor Bar generates frequencies at fnom ±2s (s= slip frequency)
Conventional Detection ExampleConventional Detection Example
During commissioning (869 installation) is important to identify the component level of the healthy rotor andthen configure the Broken Rotor Bar PKP level setting around 15 dB above it.
e.g.: If the component level for healthy rotor is read as -70dB, then the Broken Rotor Bar pickup level shouldbe set at around -60 dB to detect cracked rotor and -55 dB to detect 1 Broken Bar.
Conventional Detection DisadvantagesConventional Detection Disadvantages
MCSA Disadvantages
• Frequency spectrum provides weak contrast to detect fault signature.
• Load variation can affect detection accuracy.
• Very close to the supply frequency and difficult to detect.
Motor Current Signature Analysis (MCSA)
Power-Based Detection MethodPower-Based Detection Method
869 Method: Power Based Coherent Demodulation869 Method: Power Based Coherent Demodulation
Methodology• Voltage & current samples are
multiplied, shifting the fundamental to DC
• Fault frequency shifts down and closer to DC value
• Automatically selected when voltage is wired
Voltage and current signals multiplied to increase contrast
Power Based Coherent Demodulation AlgorithmPower Based Coherent Demodulation Algorithm
• No motor parameters information needed.
• Measured low frequency fault component is divided by the DC component.
• This normalization reduces the slip or load dependency of the fault signature
869 Method Advantages869 Method Advantages
FFT of demodulated stator current of induction machine with rotor bar fault
869 Advantages• Sharper contrast between fault
signature and fundamental
• Improved accuracy—supply frequency variation and load deviation have less effect
• Result: Fault Component clearly identifiable
869 Advantages• Sharper contrast between fault
signature and fundamental
• Improved accuracy—supply frequency variation and load deviation have less effect
• Result: Fault Component clearly identifiable
Testing of Power-Based MethodTesting of Power-Based Method
Broken Rotor Bar Testing ProcedureBroken Rotor Bar Testing Procedure
• Test motor has 22 bars. Bar diameter is 18mm.
• The depth of drilled hole was increased: 4, 8, 12, 16 and 20mm.
Broken Rotor Bar Testing ResultsBroken Rotor Bar Testing Results
• Clear difference between one bar and two bar breakages
• 12 mm hole on one bar clearly detectable
Testing Shows Algorithm is Independent of LoadTesting Shows Algorithm is Independent of Load
Implementation in the 869Implementation in the 869
Broken Rotor Bar Settings in 869Broken Rotor Bar Settings in 869
Can be set for Alarm, Latched Alarm Configurable or Disabled
Simple control of detection options and settings
Simple control of detection options and settings
Broken Rotor Bar Settings in 869Broken Rotor Bar Settings in 869
Defines the end of the frequency range where the spectral component is searched
Defines the beginning of the frequency range where the spectral component is searched
Simple control of detection options and settings
Simple control of detection options and settings
These are calculating using: f1 = system frequencys = the motor slip at full load
Broken Rotor Bar Settings in 869Broken Rotor Bar Settings in 869
Simple control of detection options and settings
Simple control of detection options and settings
Broken Rotor Bar Settings in 869Broken Rotor Bar Settings in 869
Specifies the Pickup level of the element
Simple control of detection options and settings
Simple control of detection options and settings
Using the information or measurements collected during commissioning (869 installation) and configuring this PKP level around 15 dB above it.
Broken Rotor Bar Settings in 869Broken Rotor Bar Settings in 869
Set minimum voltage level for power-based detection
Simple control of detection options and settings
Simple control of detection options and settings
Value used to switch the detection technique from a Power based Coherent demodulation to a Current based FFT detection method.
869 Broken Rotor Bar Summary869 Broken Rotor Bar Summary
• 869 dynamically evaluates whether to use current or power-based detection
• Power-based detection offers improved contrast and accuracy
• Testing verifies power-based detection accuracy independent of load
• Simple control of options and settings in the relay