Motor 869 Introduction Seminar June 2015

GEDigital Energy

Motor Protection Application in 869Motor Protection Application in 869

GE Digital Energy

www.GEDigitalEnergy.com

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



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



These are calculating using: f1 = system frequencys = the motor slip at full load


Specifies the Pickup level of the element



Using the information or measurements collected during commissioning (869 installation) and configuring this PKP level around 15 dB above it.


Set minimum voltage level for power-based detection



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

Motor 869 Introduction Seminar June 2015

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